DE102024104888A1 - Energy storage device - Google Patents

Abstract

The invention relates to an energy storage device comprising an energy storage medium and a protective structure enclosing the energy storage medium with a fiber-matrix composite protector, a fiber-matrix composite protector and a fiber-matrix semi-finished product for producing this fiber-matrix composite protector.

Description

SUBJECT OF THE INVENTION

The invention relates to an energy storage device comprising an energy storage medium and a protective structure enclosing the energy storage medium with a fiber-matrix composite protector, a fiber-matrix composite protector and a fiber-matrix semi-finished product for producing this fiber-matrix composite protector.

BACKGROUND OF THE INVENTION

Due to the increasing demand for modern energy storage concepts, particularly in the field of hydrogen or battery-electric vehicles, ever larger energy storage units with ever higher energy densities, especially hydrogen tanks or battery modules, are being installed. An uncontrolled release of the (chemically) stored energy can lead to catastrophic fires. Among other things, such a process can be triggered by mechanical damage to the energy storage device. Protective structures made of fiber composite materials are increasingly being used in such energy storage devices, as they offer advantages over metals in combining the requirements of fire protection, crash safety, insulation, and lightweight construction. Due to their typical layer-based structure and the process-related simultaneous production of the material and the resulting component, fiber composite materials offer much better adaptation options to the specific requirements of the component than metals.

Fiber composite components are already known from the state of the art which can better meet the above requirement profile, in particular by combining different functionalities, such as flame-retardant properties, special mechanical stability, tightness or electromagnetic shielding.

The US 2020/0152926 A1 describes a cover for a battery pack of an electric vehicle with a frame consisting of a layered composite. A first layer of the composite comprises a so-called "shear plate," which has a fiber-reinforced composite layer designed to counteract shear deformation in the event of an impact. As a separate element, the layered composite comprises a fire- and abrasion-resistant second functional layer, which is deposited on the shear plate and faces the battery when the shear plate is connected to the vehicle frame.

Although the fiber composite components described above can provide better protection for energy storage media, such as batteries or tanks, against external influences such as flame activity or mechanical stress, in many applications, particularly in battery technology, this protection is inadequate and/or requires such a massive protective structure that the use of composite materials is no longer competitive. Alternatively, significant amounts of flame-retardant or flame-extinguishing additives, such as phosphates or aluminum hydroxide, can be added to the composite component to improve fire protection properties. However, these adjustments lead to performance losses both on the process side (increased scrap and/or longer production times) and on the product side (increased weight). In addition, the continuously increasing power density of batteries requires ever-increasing fire protection performance, which cannot be achieved due to the limitations of current technology (additive content cannot be increased indefinitely). Furthermore, the release of such flame-retardant compounds in the event of a fire often requires critical consideration from an environmental perspective.

TASK

Against this background, the object of the present invention was therefore to provide an energy storage device with which the disadvantages described above can be overcome and which enables a functional integration of different functionalities and/or in particular has an improved protective effect with regard to flame-abrasive and/or mechanical loads, without this being accompanied by reduced processability and/or increased component weight and/or increased installation space.

DESCRIPTION OF THE INVENTION

This object is achieved according to the invention by an energy storage device, in particular for supplying a drive, such as an electric traction drive, for example for a hybrid or electric vehicle, with one or more energy storage media and a protective structure that at least partially, preferably completely, envelops the energy storage medium. The energy storage device can of course also comprise several energy storage media, e.g. several batteries. The protective structure comprises or consists of a fiber-matrix composite protector, which comprises a matrix material and a fiber material with long and/or continuous fibers, at least partially, preferably completely, embedded in the matrix material. The matrix material comprises a mat matrix polymer material or consists of it, wherein the carbon content of the matrix polymer material is ≥ 30 wt.%, preferably ≥ 40 wt.%, more preferably ≥ 50 wt.%, even more preferably ≥ 60 wt.%, even considerably more preferably ≥ 60 wt.%, even considerably more preferably ≥ 65 wt.% or ≥ 70 wt.%, and most preferably ≥ 75 wt.% or ≥ 80 wt.% or even ≥ 85 wt.%.

Preferably, the carbon content of the matrix material is ≥ 30 wt.%, preferably ≥ 40 wt.%, more preferably ≥ 50 wt.%, even more preferably ≥ 60 wt.%, even more preferably ≥ 60 wt.%, even more preferably ≥ 65 wt.% or ≥ 70 wt.%, and most preferably ≥ 75 wt.% or ≥ 80 wt.% or even ≥ 85 wt.%.

The proportion of the element carbon in the elemental composition of the matrix material and the matrix polymer material can be determined using quantitative elemental analysis.

The energy storage device according to the invention comprises an enveloping protective structure, such as a housing or a frame, i.e., a structural unit or device that serves to preserve and protect its contents from external influences. Enveloping in this context means that the protective structure completely or partially envelops the surface of the energy storage medium and thereby protects it. For example, the protective structure can directly or indirectly envelop one side of a battery or a portion thereof, for example, by partially directly covering one side of the battery. These influences can be mechanical, thermal, chemical, or electrical in nature. The protective structure comprises at least one protector, which according to the invention is a fiber-matrix composite. This protector serves in the protective structure to protect the energy storage medium at least from thermal and mechanical stress, for example, from externally acting objects, particularly in a crash scenario when the energy storage device is installed in a vehicle. An energy storage medium is a system that stores energy in a form that can be used at a later time.

These include, and are particularly preferred according to the invention, chemical storage media such as batteries.

The protective structure may comprise multiple elements, one of which is the fiber-matrix composite protector. The protective structure may also comprise multiple fiber-matrix composite protectors. However, the protective structure may also consist of the fiber-matrix composite protector, for example, a plate-shaped fiber-matrix composite protector.

In a preferred embodiment, the protective structure covers ≥ 20% of the surface of the energy storage medium, more preferably ≥ 40% of the surface, even more preferably ≥ 50% of the surface, even more preferably ≥ 60% of the surface and most preferably ≥ 70% of the surface of the energy storage medium.

In a preferred embodiment, the fiber-matrix composite protector covers ≥ 10% of the surface of the energy storage medium, more preferably ≥ 20% of the surface, even more preferably ≥ 25% of the surface, even more preferably ≥ 30% of the surface and most preferably ≥ 40% of the surface of the energy storage medium.

If the energy storage device is a battery structure for a means of transport, such as a battery-electric vehicle, then the fiber-matrix composite protector is preferably aligned with the energy storage medium—e.g., the battery—such that, during intended use in the means of transport, it is arranged beneath the energy storage medium. This allows an energy storage medium arranged in the underbody of a means of transport, such as a motor vehicle, to be protected from impact loads such as bollards. The fiber-matrix composite protector preferably covers ≥ 20% of the downward-facing surface of the energy storage medium during intended use, more preferably ≥ 40% of the surface, even more preferably ≥ 60% of the surface, even more preferably ≥ 80% of the surface, and most preferably ≥ 90% of the surface of the energy storage medium. Preferably, the fiber matrix composite protector extends even beyond this surface, thus enabling even more extensive protection of the battery and/or the battery housing.

The invention also includes a means of transport with an energy storage device arranged and designed in this way.

Battery modules are often used in modern battery structures. These are arrangements with several batteries that are combined in a generally closed frame and connected to the outside by a uniform boundary. As a rule, several such structurally subordinate battery modules are arranged in a battery housing. The protective structure according to the invention can be such a battery housing and can be used to protect an individual module, e.g., by protecting this or a part of it, in particular the fiber matrix component. posit protector, arranged between the battery housing and a battery module contained therein. However, the protective structure according to the invention can also protect multiple modules or even all modules.

The protective structure and/or fiber-matrix composite protector according to the invention can also be a so-called "intercell barrier" of a battery module, i.e., a protective plate that separates individual batteries of the battery module from one another. Such a plate prevents flames from one battery from spreading to the neighboring one(s) in the event of a fire. Particularly preferably, the protective structure and/or fiber-matrix composite protector according to the invention is an "intercell barrier" between pouch cells or prismatic cells of a battery module.

Since the fiber-matrix composite protector according to the invention protects the energy storage medium, in particular against thermal stress, such as flame exposure, it at least partially, preferably completely, covers the energy storage medium.

In a preferred embodiment, the fiber-matrix composite protector covers ≥ 20% of the surface of the energy storage medium, more preferably ≥ 40% of the surface, even more preferably ≥ 50% of the surface, even more preferably ≥ 60% of the surface and most preferably ≥ 70% of the surface of the energy storage medium.

In a preferred embodiment, the protective structure comprises a battery housing and a preferably separate fiber-matrix composite protector, wherein the fiber-matrix composite protector is preferably arranged on the inside of the battery housing, preferably between the battery and the battery housing. In another embodiment of the invention, the fiber-matrix composite protector according to the invention is arranged on the outside of the battery housing. "Separate" in this context means that the fiber-matrix composite protector is an additional component that is attached directly or indirectly to the battery housing in a detachable or non-destructively detachable manner.

In the context of the invention, polymer is understood to mean a chemical substance which has more than 50 wt.%, preferably more than 70 wt.%, more preferably more than 80 wt.%, even more preferably more than 90 wt.% and most preferably more than 95 wt.% macromolecules.

“Macromolecules” are molecules that are made up of one or more identical or similar structural units, the constitutional repeating units ( IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”), AD McNaught, A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), SJ Chalk. ISBN 0-9678550-9-8 ). Such macromolecules have more than 10 repeating units, preferably more than 15 repeating units. The molecular mass is preferably at least 3,000 g/mol, preferably at least 5,000 g/mol, particularly preferably at least 7,000 g/mol, and most preferably at least 10,000 g/mol.

Polymers are typically produced by the reaction of monomers or oligomers containing one or more of the constitutional repeating units in a polymerization reaction. An oligomer is a molecule formed from several monomers and therefore composed of a large number of structurally identical or similar structural units. In the context of the invention, oligomers are referred to when the molecule is produced from a reaction of 2-10, preferably 2-8, preferably 3-7 monomers.

According to the invention, “resins” are understood to mean precursors of thermosetting plastics, i.e. polymers (cf. IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”), AD McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997 )), which can be used in particular as components of coatings, varnishes, and paints. These are particularly preferably resins, in particular resins obtained by polyaddition or polycondensation, in particular polyurethane (PU), polyester, polyamide, urea, melamine, formaldehyde, PVC, acrylic, or epoxy resins.

A "fiber composite component" or "fiber-matrix composite" is understood to mean a material made of two or more bonded materials that has different material properties than its individual components and can serve as a component of a technical article. Such a component can be, for example, a panel or a housing, or a part of a housing, such as a base or cover plate. However, the term "fiber composite component" also encompasses fiber composite components that can form a technical article per se. The fiber composite component comprises at least one fiber material and a matrix material. The fiber composite component according to the invention is preferably a glass fiber reinforced plastic (GRP) or a carbon fiber reinforced plastic (CFRP).

The protective structure according to the invention including the fiber matrix compost protector is used to protect the energy storage medium and/or to protect against the energy storage medium, more specifically, for protection against hazards posed by the energy storage medium, such as the release of chemicals in the event of an impact. In particular, the protective structure is suitable for protecting the energy storage medium from mechanical stress and thermal stress, for example, if a fire occurs due to overheating or an uncontrolled chemical reaction of the battery chemicals. This means that the protective structure protects the energy storage medium from compressive and/or tensile and/or shear and/or impact loads, usually introduced from the outside, which could damage the energy storage medium. Furthermore, in the event of a chemical reaction and/or fire, it prevents, or at least reduces, or delays thermal stress on the components surrounding the energy storage device (such as another housing component, if present). If the fiber-matrix compost protector is a separate component and does not form the protective structure alone, it can also serve to protect the other components. For example, the protector can be a component that can be attached to a housing surrounding the energy storage medium, so that protection is provided by both the housing and the protector.

Long fibers are understood to mean fibers with a length L = 1 to 50 mm, continuous fibers (also unidirectional fibers) are understood to mean fibers with a length L > 50 mm, preferably L > 110 mm, more preferably L > 150 mm, particularly preferably L > 200 mm, and most preferably L > 500 mm. The length of the fibers of the fiber material is preferably > 30 mm, more preferably L > 150 mm, particularly preferably L > 250 mm and most preferably L > 300 mm, but generally not longer than L = 10,000 mm. Preference is given to the use of continuous fibers in the fiber-matrix composite protector according to the invention and/or the fiber-matrix semi-finished product according to the invention, in particular continuous fibers which are part of a preferably textile surface structure, such as a scrim. This results in components with particularly advantageous mechanical properties.

The matrix material of the protective structure according to the invention serves to at least partially, preferably completely embed the fiber material and optionally also to at least partially, preferably completely embed an optional additive and/or to at least partially, preferably completely dissolve an optional additive. It holds the fibers of the fiber material in their position and transfers and distributes stresses between them. It comprises a polymer material, the so-called matrix polymer material, which can in particular be a thermosetting polymer material. Examples of this are cured resins selected from the group consisting of phenol-formaldehyde resins, allyl resins, or polyester resins. This is preferably a thermosetting polymer material made from a resin and a hardener.

During the production and/or curing of a thermosetting or thermoplastic matrix polymer material, accelerators, activators, and release agents are preferably used that are soluble in the matrix material and, in the context of the present invention, are then preferably part of the matrix material. Since their presence can disrupt the advantageous carbonization of the matrix material under thermal stress, the total proportion of these additional components in the matrix material is preferably ≤ 10 wt.% or ≤ 5 wt.%, more preferably ≤ 2 wt.%, even more preferably ≤ 1 wt.%, and most preferably ≤ 0.5 wt.% or even ≤ 0.1 wt.%.

The presence of chlorine and/or heavy metals can also interfere with the carbonization process advantageous according to the invention due to radical formation. Therefore, the weight fraction of chlorine and/or metals with a density > 5 g/cm ³ in relation to the weight of the matrix material and/or the matrix polymer material is preferably ≤ 1 wt%, preferably ≤ 0.1 wt% and most preferably ≤ 0.05 wt% or even ≤ 0.01 wt%. This corresponds to the definition of a “heavy metal” according to Technical Textbook on Metals, 56th edition. Europa Lehrmittel, p. 268: Table 1: Classification of non-ferrous metals These include, for example, copper, iron and zinc.

The heteroatoms oxygen and sulfur can also slow down or disrupt carbonization due to radical formation. The weight fraction of these elements in the matrix material and/or matrix polymer material is therefore advantageously ≤ 5 wt.%, more preferably ≤ 2 wt.%, even more preferably ≤ 1 wt.%, and most preferably ≤ 0.5 wt.% or even ≤ 0.1 wt.%. The weight fraction of the sum of these elements in the matrix material is advantageously ≤ 10 wt.%, more preferably ≤ 7 wt.%, even more preferably ≤ 5 wt.%, and most preferably ≤ 3 wt.% or even ≤ 1 wt.%.

In a preferred embodiment of the invention, the matrix material comprises a thermoplastic as the matrix polymer material, wherein the thermoplastic is preferably selected from the group consisting of polyolefins, polyamides, polyether ketones, and polyterephthalates. These typically have a high carbon content in the polymer backbone, whereby a correspondingly high proportion of carbon in the matrix polymer material can be achieved by selecting the appropriate polymer. By appropriate selection of the further Components of the matrix material can be easily combined with this selection to achieve a high carbon content in the matrix material.

The weight fraction of matrix polymer material in the matrix material is preferably ≥ 50 wt.%, more preferably ≥ 60 wt.%, more preferably ≥ 70 wt.%, even more preferably ≥ 80 wt.%, and most preferably ≥ 90 wt.% or even ≥ 95 wt.%. In a preferred embodiment, the matrix material consists of the matrix polymer material.

Preferably, the matrix material has a substantially homogeneous chemical composition with the exception of optionally heterogeneous, i.e. dispersed, incorporated additives and the incorporated fiber material, i.e. that substance boundaries, with the exception of the optionally incorporated additive and the incorporated fiber material, are not present at all or only to adjacent areas of the protective device.

The spatial dimensions of the protective structure itself, as well as those of the fiber-matrix composite protector, are not restricted within the scope of the invention. The protective structure and/or the fiber-matrix composite protector can preferably be a plate, such as a fire protection plate. Preferably, the protective structure and/or the fiber-matrix composite protector is monolithic or a fiber composite sandwich plate, i.e., a plate-shaped component in a sandwich construction. In a sandwich construction, materials with different properties are combined in layers to form a component or semi-finished product. Typically, a sandwich plate comprises force-absorbing, solid, outer cover layers that are held at a distance by a relatively soft, lightweight core material. The core preferably consists of solid material (e.g., polyethylene, balsa wood), foam (e.g., rigid foam, metal foam), insulating material (e.g., rigid foam, mineral wool), or honeycomb lattice (e.g., paper, cardboard, metal, plastic). Recycled materials such as recycled polyurethane are advantageously used to increase the sustainability of the product. The core transfers any shear forces that occur and supports the outer cover layers. In a fiber composite sandwich panel, at least one of the layers, usually one of the cover layers, is formed from a fiber composite. Preferably, all outer cover layers are made of a fiber composite. Preferably, at least one, and preferably all, cover layers have a corrugated structure. The protective structure preferably comprises surface, handling, protective (in particular UV-protective), marking, and color films, as well as preferably metallic film to improve electromagnetic compatibility (EMC). Particularly preferred are also cover functional layers such as protective films for transport and in-mold coatings, for example for improved paintability.

The protective structure and/or the fiber-matrix composite protector may also comprise pores, i.e. air and/or gas inclusions, which, however, preferably do not constitute more than 5 vol.% of the total volume of the protective structure.

The protective structure and/or the fiber-matrix composite protector are often exposed to high mechanical loads in their intended use and therefore preferably have a particularly pronounced mechanical resistance and/or strength.

In a preferred embodiment of the invention, the fiber-matrix composite protector and/or the protective structure therefore has a DIN EN ISO 14125:2011-05 certain flexural strength of ≥ 100 MPa, preferably ≥ 200 MPa, more preferably ≥ 400 MPa, even more preferably ≥ 600 MPa, even more preferably ≥ 750 MPa and most preferably ≥ 1,000 MPa, but usually not more than 5,000 MPa.

In a preferred embodiment of the invention, the fiber-matrix composite protector and/or the protective structure has a DIN EN ISO 14125:2011-05 certain flexural modulus of elasticity of ≥ 5 GPa, preferably ≥ 20 GPa, more preferably ≥ 30 GPa, even more preferably ≥ 50 GPa, even more preferably ≥ 70 GPa and most preferably ≥ 100 GPa, but usually not more than 300 GPa.

In a preferred embodiment of the invention, the fiber-matrix composite protector and/or the protective structure has a DIN 14126 certain compressive strength of ≥ 100 MPa, preferably ≥ 200 MPa, more preferably ≥ 500 MPa, even more preferably ≥ 600 MPa, even more preferably ≥ 800 MPa and most preferably ≥ 1000 MPa, but usually not more than 3000 MPa.

The energy storage device according to the invention can preferably be a stationary energy storage device, but in another embodiment it can also be a battery structure for a means of transport, for example a motor vehicle or an aircraft. A preferred embodiment is a battery structure including a battery (= energy storage medium). The term battery, in the sense of the invention, is not limited to primary batteries, i.e., non-rechargeable batteries, but also includes—even more preferably—accumulators, also called secondary batteries, i.e., rechargeable batteries. rien. The battery is particularly preferably a lithium-ion accumulator, in particular a lithium-ion accumulator used for a battery-powered electric vehicle. Another preferred embodiment is an energy storage device in which the energy storage medium is a fuel storage device, such as a fuel storage device for supplying a fuel cell with fuel.

In an energy storage device, the tracking resistance of the components is of particular importance. Surface coatings of dust and moisture can cause tracking paths to form on the surfaces, allowing tracking currents to flow. This can ultimately lead to breakdown and, under certain circumstances, fire in materials that are not tracking-resistant. Particularly in fuel storage systems or lithium-ion-based battery systems, this results in designs that pose safety problems. According to the invention, it is therefore advantageous if the fiber-matrix composite protector and/or the protective structure have a high tracking resistance. Preferably, the fiber-matrix composite protector and/or the protective structure has a comparative tracking index (CTI) determined according to IEC Standard 60112 of ≥ 50, more preferably ≥ 10, more preferably ≥ 175, even more preferably ≥ 250, and most preferably ≥ 400.

Conventional protective structures with a low carbon content in the matrix polymer material are essentially completely oxidized to gaseous products such as _CO2 and thus decompose during a flame strike, e.g., when an energy storage medium explodes due to overheating or sparking, especially if the matrix polymer materials are saturated materials or materials with a high heteroatom content. One example of this is filled epoxy composites with a high oxygen content. This essentially leads to radical decomposition with CO/ _CO2 as the end product. Other non-carbon-based matrix polymer materials, such as silicones, serve as insulators, but they are equipped with non-temperature-stable binders that fail early under thermal and mechanical loads.

The inventors discovered that the use of a matrix polymer material with a minimum carbon content can significantly improve the flame retardancy. Without being bound by this theory, the inventors assume that the cyclization, dehydrogenation, and aromatization processes, which lead to a (partially) aromatic, carbonaceous structure under thermal stress (e.g., flame exposure), proceed particularly efficiently with a correspondingly high carbon content. The density of "active" conversion centers achieved by a correspondingly high carbon content during the carbonization process prevents the termination of cyclization, dehydrogenation, and aromatization processes, for example, through radical side reactions, which has a positive effect on the carbonization.

The highly endothermic carbonization process absorbs and dissipates the energy impinging on the protector during the flame impact. The carbonized layer, acting as an insulator, also shields the heat from the matrix material beyond the carbonized layer. Electrical insulation can also be achieved through the non-carbonized areas of the matrix material. The long-fiber or continuous-fiber structure stabilizes the carbon structure formed during the flame impact and enables the absorption of mechanical loads that occur during thermal stress, for example, in the form of a battery explosion, while allowing only minimal deformation of the protector. In other words, the synergistic interaction of fiber material and matrix material enables carbonization without the resulting slightly brittle structure being damaged by cracks or similar damage. In most cases, this can prevent burn-through through the composite structure. In addition, the long and/or continuous fibers enable improved properties of the protector with respect to mechanically transferable loads (tensile, compressive, shear) and improve the flame retardant effect. In contrast to short fibers, inhomogeneities (e.g., local fluctuations in fiber volume content) occur only to a minor extent in the component, and unstable structures, such as exposed short fibers, can be avoided during combustion. If necessary, a corresponding matrix polymer material can also be used only in partial sections of the fiber-matrix composite protector to achieve the desired effect in a localized manner, especially if only certain areas of the fiber-matrix composite protector are located in the immediate vicinity of the energy storage device.

The inventors also assume that the more brittle nature associated with a high carbon content ensures better impact performance.

These functions described above can be enhanced by using an unsaturated polymer material as the polymer matrix material.

The matrix material according to the invention can also be a multi-component matrix material, in particular one formed from a mixture of different polymer materials, wherein at least one of these polymer materials has a carbon content ≥ 50 wt.% and is preferably an unsaturated polymer material. The polymer material is then preferably arranged in regions in the immediate vicinity of the energy storage device or potentially other elements of the protective structure. With such a multi-material matrix approach, for example, a phenolic resin, such as a novolak with a high carbon content, can first be applied to a mold and consolidated at locally critical points that, for example, are in direct contact with the energy storage device during later use. In the subsequent step, a second saturated resin system (e.g., an epoxy resin) is applied to the consolidated structure, and the component is finally cured.

In a preferred embodiment of the invention, the matrix polymer material is a matrix polymer material cured by adding a hardener.

In a preferred embodiment of the invention, the matrix material comprises an unsaturated compound, wherein the weight fraction of the unsaturated, preferably polymeric, particularly preferably thermosetting, compound in the matrix material is ≥ 10 wt.%, preferably ≥ 20 wt.%, more preferably ≥ 40 wt.%, even more preferably ≥ 60 wt.%, even more preferably ≥ 80 wt.%, and most preferably ≥ 90 wt.%. In a particularly preferred embodiment, the matrix material consists of the unsaturated compound, which is preferably present in the form of a thermosetting polymer material. Preferably, the carbon content of this unsaturated compound is ≥ 30 wt.%, preferably ≥ 40 wt.%, more preferably ≥ 50 wt.%, even more preferably ≥ 60 wt.%, even considerably more preferably ≥ 60 wt.%, even considerably more preferably ≥ 65 wt.% or ≥ 70 wt.%, and most preferably ≥ 75 wt.% or even ≥ 80 wt.%.

In a preferred embodiment, the volume ratio of matrix polymer material to fiber material in the fiber-matrix composite protector, i.e. the fiber composite component, is 8:1 to 1:10, preferably 5:1 to 1:8 and particularly preferably 2:1 to 1:5.

In a preferred embodiment, the weight ratio of matrix polymer material to fiber material in the fiber-matrix composite protector is 5:1 to 1:20, preferably 3:1 to 1:10 and particularly preferably 1:1 to 1:8.

In a preferred embodiment, the volume ratio of matrix polymer material to optional additive in the fiber-matrix composite protector is 100:1 to 1:5, preferably 50:1 to 1:3 and particularly preferably 2:1 to 1:2.

In a preferred embodiment, the weight ratio of matrix polymer material to optional additive in the fiber-matrix composite protector is 100:1 to 1:10, preferably 50:1 to 1:6 and particularly preferably 4:1 to 1:4.

In a preferred embodiment, the volume ratio of matrix material to fiber material in the fiber-matrix composite protector, i.e. the fiber composite component, is 8:1 to 1:10, preferably 5:1 to 1:8 and particularly preferably 2:1 to 1:5.

In a preferred embodiment, the weight ratio of matrix material to fiber material in the fiber-matrix composite protector is 5:1 to 1:20, preferably 3:1 to 1:10 and particularly preferably 1:1 to 1:8.

In a preferred embodiment, the volume ratio of matrix material to optional additive in the fiber-matrix composite protector is 100:1 to 1:5, preferably 50:1 to 1:3 and particularly preferably 2:1 to 1:2.

In a preferred embodiment, the weight ratio of matrix material to optional additive in the fiber-matrix composite protector is 100:1 to 1:10, preferably 50:1 to 1:6 and particularly preferably 4:1 to 1:4.

In a preferred embodiment, the weight fraction of fiber material in the total mass of the fiber-matrix composite protector is 10 to 95 wt.%, preferably 20 to 90 wt.%, more preferably 30 to 85 wt.%, even more preferably 40 to 80 wt.% and most preferably 50 to 75 wt.%.

In the fiber-matrix composite protector, the fiber volume content is preferably in a range of 30-70 vol%, preferably 35-65 vol%, even more preferably 40-60 vol%, and most preferably 45-55 vol%. This achieves suitable mechanical properties for the protection, in particular suitable ductility.

In a preferred embodiment of the invention, the fiber material has at least in sections, preferably completely, a surface structure, preferably a textile surface structure, which is partially, substantially (i.e., to more than 90 vol%), or even completely embedded in the matrix material.

Particularly preferably, the surface structure is selected from the group consisting of scrims, knitwear, woven fabrics, braids, nonwovens or mixtures thereof.

According to the invention, a nonwoven is understood to be a structure made of fibers of limited length, continuous fibers (filaments), or cut yarns of any type and origin, which have been joined together in any way to form a fiber layer and bonded together in any way. This excludes the crossing or entangling of yarns, as occurs in weaving, knitting, lacemaking, braiding, and the production of tufted products. This definition corresponds to the DIN EN ISO 9092 standard. According to the invention, the term "nonwoven" also includes felt materials. Films and papers, however, are not considered nonwovens.

For the purposes of the invention, braiding refers to the regular interlacing of several strands of flexible material. The difference from weaving is that in braiding, the threads are not fed at right angles to the main product direction.

Particularly preferred within the scope of the invention is the use of a fiber material in the form of a woven fabric. According to the invention, a woven fabric is understood to be a textile fabric consisting of two thread systems, warp (warp threads) and weft (weft threads), which, viewed on the fabric surface, intersect in a pattern at an angle of exactly or approximately 90°. Each of the two systems can be composed of several warp or weft types (e.g., ground, pile, and filling warp; ground, binding, and filling weft). The warp threads run in the longitudinal direction of the fabric, parallel to the fabric edge, and the weft threads run in the transverse direction, parallel to the fabric edge. The threads are connected to the fabric primarily by friction. In order for a fabric to be sufficiently slip-resistant, the warp and weft threads must usually be woven relatively tightly. Therefore, with few exceptions, the fabrics also have a closed appearance. This definition corresponds to the DIN 61100, Part 1 standard.

According to the invention, the terms woven and nonwoven also include tufted textile materials. Tufting is a process in which yarns are anchored into a woven or nonwoven fabric using a machine powered by compressed air and/or electricity.

According to the invention, knitwear refers to textile fabrics made from thread systems by stitch formation. This includes both crocheted and knitted fabrics.

According to the invention, a scrim is understood to be a fabric consisting of one or more layers of parallel, stretched threads. The threads are typically fixed at the intersection points. Fixation occurs either by a bonded connection or mechanically through friction and/or form fit. The scrim is preferably selected from a monoaxial or unidirectional, a biaxial, or a multiaxial scrim.

The fiber material preferably comprises multiple layers, each layer having an anisotropic structure, i.e., the fibers within the layer exhibit a specific fiber orientation. This can produce an anisotropic mechanical behavior of the layered composite. Particularly preferably, the layers are formed by non-crimp fabrics, thereby creating a non-crimp stack, with the non-crimp fabrics preferably having different fiber orientations (such as 0°, + and - 45°, and 90° relative to the longitudinal axis if the fiber-matrix composite protector is a rectangular plate) to thereby achieve a "quasi-isotropic arrangement."

The fibers of the fiber material are preferably selected from the group consisting of glass fibers, carbon fibers, ceramic fibers, basalt fibers, boron fibers, steel fibers, polymer fibers such as synthetic fibers, in particular aramid and nylon fibers, or mixtures of the aforementioned. Glass fibers and carbon fibers are particularly preferred. Using such fibers, protective structures according to the invention with particularly high mechanical resistance can be produced.

Carbon fibers are particularly preferred for protective structures for aircraft applications, particularly due to their weight advantage and higher modulus of elasticity, while glass fibers are particularly preferred in automotive applications.

In another preferred embodiment, the fibers of the fiber material are natural fibers, in particular natural polymer fibers.

Natural fibers are fibers that originate from natural sources such as plants, animals, or minerals and can be used directly without further chemical conversion reactions. Examples of these according to the invention are flax, jute, sisal, or hemp fibers, as well as protein fibers or cotton. Regenerated fibers, i.e., fibers that come from naturally occurring, growing raw materials using chemical processes.

Corresponding fiber materials are characterized by improved recyclability and thus particularly high sustainability.

The fiber-matrix composite protector can also be used in the protective structure in combination with a separate, second metallic protector. In a preferred embodiment of the invention, the energy storage device therefore comprises a second, preferably plate-shaped protector made of a metallic material, in particular steel, which is preferably bonded to the fiber-matrix composite protector in a material-to-material, form-fitting, or cohesive manner, preferably by bonding.

The fiber composite component, i.e., the fiber-matrix composite protector, is preferably integral, i.e., monolithic. Particularly preferably, the fiber composite component is obtained by integral curing during its production. In another preferred embodiment, the fiber composite component is a fiber composite sandwich panel, i.e., a panel-shaped component with a sandwich construction.

However, the fiber composite component, i.e. the fiber-matrix composite protector, can also comprise several layers, preferably in a sandwich construction, wherein one of the layers can be a metal plate, in particular a steel or copper plate.

In a preferred embodiment of the invention, one of the layers of the fiber-matrix composite protector is a layer with a matrix material having a carbon content ≥ 50 wt.%, e.g., a cured phenolic resin, and a further layer can be a layer with a lower carbon content, e.g., a cured epoxy resin layer.

As already described, the matrix material preferably comprises an unsaturated compound, more preferably an unsaturated polymer.

The one or more unsaturated carbon-carbon and/or carbon-nitrogen bonds of the unsaturated compound are very efficiently converted into a (partially) aromatic, carbonaceous structure during a flame reaction. The inventors assume that the use of an unsaturated carbon-nitrogen bond results in _N2 elimination, which is part of the carbonization process. In a preferred embodiment of the invention, the unsaturated compound therefore has a carbon-nitrogen bond, in particular a carbon-nitrogen double bond.

In another preferred embodiment of the invention, the unsaturated compound has an unsaturated carbon-carbon bond, in particular a carbon-carbon double bond.

More preferably, the unsaturated compound has two, three, four, five or more unsaturated carbon-carbon bonds and/or unsaturated carbon-nitrogen bonds.

In a preferred embodiment of the invention, the unsaturated compound is a thermosetting polymer material having at least one constitutional repeating unit which has at least one functional group comprising an unsaturated carbon-carbon bond and/or an unsaturated carbon-nitrogen bond.

In a preferred embodiment, the unsaturated compound has two or more bonds selected from the group consisting of unsaturated carbon-carbon bonds and unsaturated carbon-nitrogen bonds, and at least two of these bonds are conjugated. Conjugation of the unsaturated bonds facilitates the formation of an aromatic structure, whereby the carbonization processes occur preferentially and thus to a greater extent.

Preferably, the functional group is part of an aromatic system, such as a furanyl, thiophenyl, pyrolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, phenyl, benzoyl, hydroxyphenyl, or pyridinyl group. The presence of an aromatic system energetically favors further aromatization during the carbonization process. The aforementioned groups are particularly preferably part of a repeating unit(s) when the unsaturated compound is a polymer.

Preferably, the unsaturated compound is a thermosetting polymer selected from the group consisting of phenolic resins, cured melamine resins, cured furan resins, and cured polyurethane resins. Materials obtained from the curing of phenolic resins, preferably novolaks, are particularly preferred. The thermosetting polymer materials are preferably almost completely crosslinked, where almost completely means that at least 40%, preferably at least 50%, more preferably at least 60%, even more preferably at least 70%, and most preferably tensile tests at least 80% of the potentially crosslinkable functional groups are crosslinked.

The thermosetting polymer material is preferably a phenolic resin obtained by crosslinking a thermosetting phenol-formaldehyde resin. The molar ratio of formaldehyde to phenol (F/P ratio) in the reaction mixture for producing the thermosetting phenol-formaldehyde resin is particularly preferably ≤ 1, preferably ≤ 0.9, in particular in the range 0.6-0.9, preferably 0.75-0.85.

The thermosetting polymer material according to the invention is preferably obtained by reacting a resin, such as a phenolic resin, with a hardener. The hardener is preferably selected from the group consisting of formaldehyde donors, such as hexamethylenetetramine, or melamine or urea condensates containing methylol groups. The hardeners are preferably used in an amount of 1 to 50 wt.%, preferably 2 to 15 wt.%, more preferably 2 to 5 wt.%, based on the phenolic resin.

In a preferred embodiment of the invention, the matrix material and/or the matrix polymer material has a carbon yield upon thermal pyrolysis of ≥ 40%, preferably ≥ 50%, even more preferably ≥ 55%, even more preferably ≥ 60%, and most preferably ≥ 65%. The carbon yield can be determined in a thermogravimetric analysis, whereby the thermal treatment of an approximately 30 mg sample is carried out in an N ₂ atmosphere (60 ml/min purge gas rate) and a linear heating program is run from 20 °C to 1000 °C at a heating rate of 10 °C/min. The carbon yield corresponds to the ratio of residual mass to the initial mass of the matrix material or the matrix polymer material. With a correspondingly high yield, the advantages of the invention are particularly pronounced.

The matrix material of the protective structure according to the invention may further comprise an additive.

The additive is particularly preferably a flame retardant, which is preferably selected from the group consisting of nitrogen-based flame retardants, inorganic flame retardants such as graphite salts, aluminum trihydroxide, antimony trioxide, ammonium polyphosphate, phosphinates such as aluminum diethylphosphinate, mica, muscovite, guanidines, triazines, sulfates, borates, cyanurates, salts thereof, and mixtures thereof. This can further increase the flame retardancy of the fiber-matrix composite protector. In contrast to the protective structures known from the prior art, a significantly lower content of additives, in particular flame retardants, can be used due to the intrinsic flame retardancy resulting from the carbonization behavior, which has a particularly positive effect on the mechanical properties of the protective structures. In a preferred embodiment of the invention, the matrix material comprises ≤ 50 wt.% additives, preferably ≤ 45 wt.% additives, more preferably ≤ 40 wt.% additives, even more preferably ≤ 35 wt.%, even more preferably ≤ 30 wt.% additives and most preferably ≤ 25 wt.% additives, but preferably also ≥ 0.01 wt.%.

The flame retardant is preferably present in the fiber-matrix composite protector in a flat form, for example, in the form of a plate. In this case, the flame retardant is preferably mica.

Flame-retardant reinforcement can also be provided only on specific sections of the fiber-matrix composite protector. For example, in a flat design of the fiber-matrix composite protector, a flame-retardant plate can be applied or incorporated only on a portion of the surface. Alternatively, a varying concentration of flame-retardant additive can also be provided in the matrix material.

For flame retardancy, a fiber reinforcement structure with flame retardancy properties can also be provided as fiber material in the fiber-matrix composite protector.

In other preferred embodiments, the additive is selected from the group consisting of antioxidants, light, in particular UV stabilizers, plasticizers, foaming agents, electrical conductors, heat conductors, dyes, electrical insulators, fillers, in particular for improving the mechanical properties such as impact modifiers or rubber or thermoplastic particles as well as mixtures of the aforementioned.

The additive can be dissolved or dispersed in the matrix material. If dispersed, it is preferably in the form of a powder, flakes, tubes, or mixtures of the aforementioned forms.

If the additive is a flame retardant, it is preferably selected from the group of active, i.e., cooling, flame retardants or from the group of passive, i.e., insulating, flame retardants. The flame retardant is particularly preferably an intumescent flame retardant.

Finally, the matrix materials according to the invention can also contain wetting agents. Wetting agents are surface-active substances that typically have a hydrophobic and a hydrophilic molecular moiety. A distinction is made between nonionic, anionic, and cationic wetting agents. Wetting agents reduce the viscosity of the resin. This improves the penetration of the fiber material, ultimately leading to a stronger bond between the fiber material and the matrix material. The synergistic effect, particularly the stabilization of the (partially) carbonized structure, is thereby enhanced.

Nonionic wetting agents include, for example, esters and amides of fatty acids (saturated or unsaturated carboxylic acids, which generally have 4 to 26 carbon atoms in the molecule), fatty amines (primary amines, which generally have 6 to 22 carbon atoms in the molecule), or polyethylene glycol ethers or polypropylene glycol ethers of alcohols, alkylphenols, or fatty acid alkanolamides. Anionic wetting agents include, for example, salts of alkylmalonic or alkylsuccinic acid, alkylsulfonates, fatty acid ester sulfonates, perfluorinated alkylsulfonates, or sulfated fatty acid amides. Cationic wetting agents include substances such as fatty amine salts, salts of alkylenediamines and polyamines, alkylbenzylammonium salts, or alkylpyridinium salts.

In a preferred embodiment of the invention, the fiber-matrix composite protector comprises connecting elements, for example for further elements of the protective structure, wherein the connecting elements are preferably selected from the group consisting of retainers, embossments, ribs, through holes and blind holes.

The provision of ribs is particularly preferred, since corresponding ribbing leads to higher mechanical strength.

In this context, the semi-finished product according to the invention has the advantage of enabling very precise positioning of several semi-finished products relative to one another. This allows, for example, ribs to be applied as semi-finished products to a monolithically formed semi-finished plate with great precision. Through subsequent thermal finalization, i.e., consolidation, fiber-matrix composite protectors with a reinforcing corrugated rib pattern can then be generated very easily.

Likewise, the semi-finished product according to the invention can also be used very easily to produce hole reinforcements or to incorporate inserts into the fiber-matrix composite protector. Therefore, the fiber-matrix composite protector preferably comprises one or more inserts and/or one or more hole reinforcements.

The inventors have also discovered that the semi-finished product according to the invention allows for the particularly efficient and simple production of a fiber-matrix composite protector with varying wall thickness. For this purpose, plate-shaped layers of semi-finished products can be stacked on top of one another and then thermally finished. Varying the wall thickness of such a plate, in particular reducing it in the area of a curve, is particularly preferred.

The invention also relates to a fiber-matrix composite protector for a protective structure for an energy storage device as defined in any of the claims and/or the preceding and following sections of the description.

The invention also relates to a protective structure for an energy storage device as defined in one of the claims and/or the preceding and following sections of the description text.

Particularly preferably, the protective structure is a battery housing, in particular a battery housing for the battery of a battery electric vehicle, such as a lithium-ion accumulator.

Preferably, the protective structure is the underrun protection or part of the underrun protection of a motor vehicle and the invention preferably relates to a motor vehicle comprising an energy storage device with a corresponding protective structure.

The protective structure is preferably a vehicle component, in particular a motor vehicle component such as a body component. Particularly preferably, the protective structure is an underbody protection (also called an impact protection plate or underride protection) or bumper, or a battery housing, or battery housing part, and is preferably in the form of a protective plate.

The protective structure can also be part of an aircraft or spacecraft, a rail vehicle component, or a part of the aforementioned. Further preferred motor vehicle components are selected from the group consisting of trunk loading floors, instrument panels, door and roof panels, underbody protection parts, structural components, wheelhouses, engine compartment parts, brake and clutch linings and discs, sound insulation, shear panels, and seals.

The invention preferably also relates to a vehicle, in particular an automobile, comprising the energy storage device according to the invention and/or the protective structure according to the invention.

Particularly preferred is the use of the fiber-matrix composite protector as part of a battery housing (which does not necessarily have to be part of a motor vehicle), especially for a lithium-ion battery. Particularly preferred is the fiber-matrix composite protector and/or the protective structure as the base or cover plate.

The protective structure and/or fiber-matrix composite protector can also be an “intercell barrier.”

The invention also relates to a fiber-matrix semi-finished product, preferably a prepreg, for producing a fiber-matrix composite protector according to the invention, comprising a fiber material comprising or consisting of long and/or continuous fibers and a preferably curable, in particular heat-curable, resin composition, wherein the carbon content of the curable resin composition is ≥ 50 wt. %, preferably ≥ 70 wt. %. The curable resin composition at least partially, preferably completely, envelops the long and/or continuous fibers of the fiber material. The fiber material is at least partially, preferably completely, in the form of a preferably textile surface structure.

Preferably, the curable resin composition comprises an unsaturated compound, preferably in the form of a resin having at least one constitutional repeating unit.

Particularly when using a phenolic resin, such as a novolak, as a thermosetting resin composition, the semi-finished product according to the invention enables good positioning and thus near-net-shape pressing due to its low tack. This is significantly easier and better than with dry textiles, as the semi-finished product according to the invention offers excellent handling due to its low tack and sufficient, but not excessive, rigidity. Individual modeling of the protector's shape is therefore very simple.

For example, ribbing, local patches, i.e. thickening, hole reinforcement and stacks can be manufactured very easily.

The value of the semi-finished product according to the invention determined with an ASTM D3121 Rolling Ball Tack Tester is preferably > 15 cm, more preferably > 20 cm, even more preferably > 25 cm and most preferably > 30 cm.

Inserts can also be incorporated into the fiber-matrix composite protector in a very simple manner. For this purpose, appropriate inserts can be incorporated into the semi-finished products, or the semi-finished products can be placed around the inserts. After thermal finalization, an integral component is then obtained.

Preferably, the resin used comprises a constitutional repeating unit which comprises at least one functional group having an unsaturated carbon-carbon bond or an unsaturated carbon-nitrogen bond.

The fiber-matrix semi-finished product is preferably designed such that at least one surface of the semi-finished product is substantially completely covered, i.e., ≥ 70%, preferably completely, with matrix material. Such a fiber-matrix semi-finished product is characterized by particularly good processability. In particular, contact with additional fiber layers to produce complex components can be made via the completely covered side, thus creating the smallest possible interlaminar pore volume. The resulting protective structures can therefore withstand particularly strong mechanical loads. The invention also relates to a protective structure obtained by thermally joining such semi-finished products.

The preferably used curable resin composition of the fiber-matrix semi-finished product preferably comprises or is a phenolic resin, in particular a novolak, which is particularly preferably dry, i.e., contains less than 10 wt. %, preferably less than 5 wt. %, even more preferably less than 1 wt. % solvent. Such dry, preferably thermosetting resin compositions of the fiber-matrix semi-finished product are preferably obtained by partial curing with a curing agent, preferably an amine curing agent such as hexamethylenetetramine. The aforementioned phenolic resins, in particular novolaks, particularly in the aforementioned preferred embodiments, exhibit high storage and handling stability (in particular, low or no tackiness) at room temperature, but also up to temperatures of 60°C. This high stability is particularly pronounced when the phenolic resins, in particular novolaks, are in the "B-stage," since then further polymerization and crosslinking reactions do not occur or only occur to a minor extent. This is particularly preferably achieved by partially curing the preferably thermosetting compositions using an amine hardener such as hexamine.

The preferably thermosetting resin composition, which in particular comprises a novolak, preferably has a glass transition temperature (T _g ) of ≥ 4 °C, preferably ≥ 8 °C, more preferably ≥ 12 °C, even more preferably ≥ 15 °C and most preferably ≥ 20 °C. The use of a novolak, especially with the T _g values described above, prevents the fiber-matrix semi-finished product from feeling sticky. This also results in particularly good cuttability of the fiber-matrix semi-finished product.

The weight fraction of the fiber material in the fiber-matrix semi-finished product is preferably in the range of 25-60 wt.%, preferably 30-55 wt.%, even more preferably 35-50 wt.%, and most preferably 35-50 wt.%. Within these value ranges, both dry spots in the fiber-matrix semi-finished product and excessive matrix outflow during processing can be avoided.

By using a novolak, coloration, such as that which occurs with resoles, can generally be avoided or at least reduced in the fiber-matrix semi-finished product and/or the protective structure.

When using a phenolic resin for the fiber-matrix semi-finished product, in particular a novolak, the thermosetting composition is preferably in the so-called "B-stage," i.e., the composition is still swellable and meltable, but is already insoluble in solvents. This state is generally achieved by thermal treatment at a maximum temperature of 160°C. Such resins enable, in particular, the easy integration of surface, handling, protective, in particular UV-protective, marking, and color films, as well as films to improve electromagnetic compatibility (EMC). Cover functional layers such as protective films for transport and in-mold coating, for example, for improved paintability, are also particularly preferred. Therefore, the fiber-matrix semi-finished product preferably comprises such films. The protective structure according to the invention preferably also comprises such films. The use of phenolic resins, in particular in the "B-stage," also enables near-net-shape pressing due to their low flowability.

In terms of process technology, the use of the above-described "B-stage" phenolic resins, particularly novolaks, enables further simplification, as the reaction has already progressed to the final curing stage during the final component production. This simplifies and accelerates the overall process. However, when using a novolak with an amine hardener, the basic structure of the curable composition in the "B-stage" is no longer altered during the final curing of the fiber-matrix semi-finished product, which produces the protective structure according to the invention. This leads to high application variability (a type of "phenolic resin-based organosheet") and a very short reaction time during the final curing step. Furthermore, ammonia escapes from the resin matrix much more easily, resulting in significantly less pore formation compared to water-separating curing (e.g., curing with compounds containing hydroxymethyl groups). This allows for the creation of thicker-walled and more stable protective structures.

The invention also relates to a system (“kits of parts”) for producing a fiber-matrix semi-finished product, as defined in claim 14 and above, wherein the composition comprises a fiber material and a preferably thermosetting resin composition in powder form. The resin composition is preferably dry, i.e., contains less than 10 wt. %, preferably less than 5 wt. %, even more preferably less than 1 wt. %, of solvent. The dry, preferably thermosetting compositions preferably contain hardeners, in particular amines such as hexamethylenetetramine (also “hexamine”). The preferably thermosetting composition is preferably in the “A state,” in particular in the “A2 state,” in this powdered system.

The invention also relates to a system (“kits-of-parts”) for producing a fiber-matrix semi-finished product, wherein the composition comprises a fiber material and a preferably thermosetting resin composition in powder form, wherein the thermosetting resin composition is an epoxy resin whose carbon content is ≥ 30 wt.%, preferably ≥ 40 wt.%, more preferably ≥ 50 wt.%, even more preferably ≥ 60 wt.%, even considerably more preferably ≥ 60 wt.%, even considerably more preferably ≥ 65 wt.% or ≥ 70 wt.%, and most preferably ≥ 75 wt.% or ≥ 80 wt.% or even ≥ 85 wt.%.

The addition of additives can be carried out easily during handling using a powder spreader. The additives can be mixed in as a separate powder. Preferably, the addition of additives, in particular the hardener, is carried out in such a way that they are distributed essentially homogeneously in the resin powder. In contrast to the use of individual powders of thermosetting composition and hardener, this avoids segregation of the powders due to density differences during the manufacturing process, thereby ensuring a homogeneous distribution of the hardener in the fiber-matrix semi-finished product. The system therefore preferably also comprises a hardener that is dissolved and/or dispersed in the powdered, thermosetting resin composition. In another embodiment, the system comprises the hardener as a separate powder. The additives, in particular the hardener, are preferably but dissolved and/or dispersed in the resin composition.

The invention also relates to the use of the fiber-matrix composite protector according to the invention in an energy storage device such as a battery structure. The invention also relates to the use of the fiber-matrix composite protector according to the invention for protecting an energy storage device and/or a protective structure for protecting against a battery, more specifically for protecting against hazards posed by a battery.

The invention also relates to the use of a matrix polymer material and/or a matrix material with ≥ 50 wt. %, preferably ≥ 70 wt. %, carbon content in a protective structure for an energy storage device, in particular in a protective structure of an energy storage device of an electric vehicle. A matrix material and/or matrix polymer material with an unsaturated compound is particularly preferred, in particular the use of a thermosetting polymer material with at least one constitutional repeating unit having an unsaturated carbon-carbon bond and/or an unsaturated carbon-nitrogen bond.

Particularly preferred is the use of a thermosetting polymer material obtained from a phenolic resin, in particular a novolak, by curing as a matrix polymer material for a fiber-matrix composite protector for an energy storage device, in particular for a protective structure for a battery housing of an electric vehicle. The invention also relates to the use of a thermosetting polymer material obtained from a phenolic resin, in particular a novolak, by crosslinking as a matrix polymer material in a fiber-matrix composite protector for an energy storage device with an energy storage medium and a protective structure that at least partially, preferably completely, envelops the energy storage medium, wherein the protective structure and/or the energy storage device/or the fiber-matrix composite protector are preferably connected to one another. Particularly preferably, the fiber-matrix composite protector is arranged, in particular fastened, on one of the inner or outer sides of the protective structure and/or on the energy storage medium.

The invention also relates to the production of a fiber-matrix semi-finished product and a fiber-matrix composite protector from this fiber-matrix semi-finished product. A method for producing the fiber-matrix composite protector comprises a first step for producing the fiber-matrix semi-finished product and a subsequent thermal finishing step, and is presented below as an example.

Step 1: Production of the fiber matrix semi-finished product by powder lamination

In the first step of producing the protective structure, novolak (obtained from formaldehyde and phenol, F/P ratio <1) with a weight-average molecular weight of ~500 g/mol and the hexamethylenetetramine hardener contained therein is applied to a textile, melted at a temperature of 100-150 °C, and then introduced into the fiber material by applying force into the textile structure using a double-belt press. The carbon content of the novolak with hardener is > 74 wt.%. Cooling produces a fiber-matrix semi-finished product. The degree of conversion, i.e., the extent of partial curing, of the thermosetting matrix material can be regulated via the pressing time and/or pressing temperature and/or pressing pressure. This allows the brittleness of the material to be controlled. After cooling, the novolak is in the "B-stage," with a carbon content of > 76 wt.%.

Step 2: Thermal finalization to produce the protective structure

In the subsequent second process step, the fiber-matrix semi-finished product obtained in step 1 is formed into the desired final contour (e.g., L-shaped profile, etc.) at elevated temperature using shaping tools (approx. 140-200°C). Preferably, several fiber-matrix semi-finished products can be stacked on top of each other, i.e., forming a so-called stack, in order to obtain a uniform end product after final curing.

Steps 1 and 2 can be performed both continuously, i.e., directly following one another in time, or discontinuously, i.e., separated in time. Using the method according to the invention, significantly thicker-walled components, such as laminates, can be produced than those known from the prior art. Conventional potting resin systems are generally difficult to process due to the resin quantity, the impregnation distance, and the exothermic nature, so the component thickness is limited. This applies particularly to the conventional wet-molding process, in which, beyond a certain thickness, the resin system can no longer fully infiltrate the fiber layers.

When using an RTM process, however, one or more gate points are used, which usually cannot be perfectly concealed. Furthermore, the gate always causes an uneven distribution of the matrix material, since the fiber material is not evenly distributed due to the above-mentioned described problems, especially in large structures, are very difficult to infiltrate completely.

Since in the process according to the invention the final component is achieved by joining thin layers that are almost completely impregnated with resin, these problems do not exist here.

• I) Herstellung des Faser-Matrix-Halbzeugs durch
  1. a) Aufbringen einer trockenen, pulverförmigen und wärmehärtbaren Harzzusammensetzung, mit einem Kohlenstoffanteil ≥ 50 Gew.-%, insbesondere eines Novolaks, zur Herstellung eines Phenoplasts, auf ein Textil,
  2. b) Aufschmelzen der Harzzusammensetzung bei 100-240 °C und
  3. c) Infiltrieren des Textils mit Harz, vorzugsweise durch Anwenden einer Kraft,
• II) Herstellung eines Faser-Matrix-Komposit-Protektors aus einem oder mehreren der unter Schritt I) hergestellten Faser-Matrix-Halbzeuge durch
  1. a) Optional: Stapeln mehrerer Faser-Matrix-Halbzeuge in einer Presse
  2. b) Verpressen des Faser-Matrix-Halbzeuges oder des Stapels der Faser-Matrix-Halbzeuge bei einer Temperatur von 150 °C bis 250° C, insbesondere 160 °C bis 180 °C.

In a preferred embodiment of the invention, the fiber-matrix composite protector according to the invention is therefore a plate having a thickness of ≥ 0.3 mm, preferably ≥ 1 mm, more preferably ≥ 1.5 mm, even more preferably ≥ 2.5 mm, even more preferably ≥ 3.5 mm, and most preferably ≥ 5 mm. In such a plate, the fiber material is preferably substantially completely embedded (i.e., more than 95 vol%). This fiber-matrix composite protector is preferably obtained by a process comprising the following steps:

• I) Production of the fiber-matrix semi-finished product by
  1. a) applying a dry, powdery and thermosetting resin composition, with a carbon content ≥ 50 wt.%, in particular a novolak, to produce a phenolic resin, to a textile,
  2. b) Melting the resin composition at 100-240 °C and
  3. c) Infiltrating the textile with resin, preferably by applying a force,
• II) Production of a fiber-matrix composite protector from one or more of the fiber-matrix semi-finished products produced under step I) by
  1. a) Optional: Stacking of several fiber matrix semi-finished products in one press
  2. b) Pressing the fiber-matrix semi-finished product or the stack of fiber-matrix semi-finished products at a temperature of 150 °C to 250 °C, in particular 160 °C to 180 °C.

The process according to the invention also enables the use of fine-mesh fabrics with a low basis weight (≤ 200 g/m ² ), which cannot be processed in conventional manufacturing processes, such as wet pressing, due to difficult infiltration. The invention therefore preferably relates to a fiber-matrix semi-finished product and a fiber-matrix composite protector comprising fine-mesh fabric with a basis weight ≤ 200 g/m ² , preferably ≤ 150 g/m ² , even more preferably ≤ 120 g/m ² , and most preferably ≤ 90 g/m ² . The fiber-matrix composite protector with a corresponding fabric is preferably obtained by a process comprising the steps defined above.

Preferably, the method also includes the mechanical processing of the semi-finished products and/or the fiber-matrix composite protector.

The invention also includes a method for repairing fiber-matrix composites, in which a fiber-matrix semi-finished product according to the invention is applied to a defect or flaw in a preferably cured fiber-matrix composite component and a thermal finalization is subsequently carried out.

LIST OF FIGURES

• 1 und 4 zeigen schematisch Schritt 1 eines Verfahrens zur Herstellung eines erfindungsgemäßen Faser-Matrix-Komposit-Protektors.
• 2 zeigt schematisch Schritt 2 eines Verfahrens zur Herstellung eines erfindungsgemäßen Faser-Matrix-Komposit-Protektors.
• 3 zeigt schematisch einen Multimatrix-Faser-Matrix-Komposit-Protektor mit lokal unterschiedlichen Matrixsystemen.

The present invention is explained in more detail below with reference to the exemplary embodiments shown in the figures.

• 1 and 4 show schematically step 1 of a method for producing a fiber-matrix composite protector according to the invention.
• 2 shows schematically step 2 of a method for producing a fiber-matrix composite protector according to the invention.
• 3 shows a schematic representation of a multimatrix fiber-matrix composite protector with locally different matrix systems.

DESCRIPTION OF AN EMBODIMENT

1 and 4 show schematically and by way of example a method for producing the fiber-matrix composite protector according to the invention, ie the composite component, as can be used for example for a cover or base of a battery housing for an electric vehicle.

To manufacture such a composite component, a winder is loaded with a glass fabric. The total grammage of the glass fabric and the distribution of the proportions of different fiber orientations (e.g., at 0°, + and - 45°, and 90° relative to the vehicle's longitudinal axis) are determined during the design process according to the mechanical and other loads on the cover/floor. In a simple basic structure, the proportions of the orientations at 0°, - 45°, 45°, and 90° are equal, resulting in a so-called quasi-isotropic laminate.

With the help of the unwinder, the glass fabric is fed to a powder lamination system with a powder spreader. With the help of the powder spreader, a resin-hardener mixture is applied to the fabric in the form of a The powder is distributed over the entire surface and then fed into a double-belt press (press temperature -120 °C). The resin material is a novolak (obtained from formaldehyde and phenol, F/P ratio 0.75) with a weight-average molecular weight of -500 g/mol and contains hexamethylenetetramine hardener. The resin material is pressed into the fabric, embedding the reinforcing fibers in the resin. This process step is schematically shown in 1 and 4 After cooling to room temperature, the resulting prepreg material is cut and/or rolled or stacked.

The resulting fiber-matrix semi-finished product, in this case the prepreg material, is storage-stable at room temperature (~23 °C) (i.e., no conversion to the "C-state" occurs over a period of at least 2 days) and exhibits essentially no stickiness.

To produce the fiber-matrix composite protector, the semi-finished product is cut to the desired contour in step 2 of the process and stacked to the desired thickness. The stack is then placed in an open press with a crimping edge, the press is closed, and the component is pressed at a temperature of 140-200 °C in a controlled manner, thus completely curing the matrix polymer material. The curing time is several minutes. This process step is carried out in 2 shown schematically.

The component is then removed from the mold and moved on to the final processing steps.

Depending on the arrangement of the battery cells in the housing, certain areas of the cover are exposed to particularly high temperatures in the event of a battery fire. In one embodiment of the invention, the matrix polymer material of the fiber-matrix protector therefore only comprises a matrix material with a correspondingly high carbon content, e.g., a novolak with a carbon content of ≥ 70 wt. %, at these locations exposed to particularly high stresses. Such locations are shown in the schematic representation of the 3 highlighted in black.

Reference symbol

1

Curable resin composition in powder form

2

Textile fiber material layer

3

Fully resin-coated surface side fiber matrix semi-finished product

4

Fiber-matrix semi-finished product

5

protective structure

6

Novolak-enriched matrix zone of the protective structure

7

Unwinder with glass fiber fabric

8

Powder spreader

9

Heating zone of the double belt press

10

Cooling zone of the double belt press

11

Winding device semi-finished product

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2020/0152926 A1 [0004]

Cited non-patent literature

• IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”), A. D. McNaught, A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), S. J. Chalk. ISBN 0-9678550-9-8 [0023]
• IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”), A. D. McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997 [0025]
• Technical Textbook on Metals, 56th edition. Europa Lehrmittel, p. 268: Table 1: Classification of non-ferrous metals [0031]
• DIN EN ISO 14125:2011-05 [0039, 0040]
• DIN 14126 [0041]

Claims (15)

Energy storage device, in particular for supplying an electric traction drive, with • an energy storage medium, • a protective structure which at least partially, preferably completely, covers the energy storage medium, with o a fiber-matrix composite protector which has a matrix material which comprises a matrix polymer material, and a fiber material with long and/or continuous fibers which is at least partially, preferably completely, embedded in the matrix material, characterized in that the carbon content of the matrix polymer material is ≥ 50% by weight, preferably ≥ 70% by weight. Energy storage device according to Claim 1 , wherein the matrix polymer material comprises or consists of a preferably cross-linked and cured epoxy resin or a polyaramid. Energy storage device according to Claim 1 or Claim 2 , wherein the fiber-matrix composite protector comprises the fiber material at least in sections, preferably completely, in the form of a preferably textile surface structure. Energy storage device according to Claim 3 , wherein the preferably textile surface structure is selected from the group consisting of scrims, woven fabrics, fleece or combinations of the aforementioned. Energy storage device according to one of the preceding claims, wherein the fibers of the fiber material are selected from the group consisting of glass fibers, carbon fibers, basalt fibers, ceramic fibers, steel fibers, polymer fibers such as synthetic fibers, in particular aramid and nylon fibers, or natural polymer fibers such as flax, hemp, or protein fibers. Energy storage device according to one of the preceding claims, wherein the fiber-matrix composite protector is plate-shaped. Energy storage device according to one of the preceding claims, wherein the protective structure further comprises one or more metal elements, such as metal plates, which are preferably connected to the fiber-matrix composite protector. Energy storage device according to one of the preceding claims, wherein the fiber-matrix composite protector is monolithic. Energy storage device according to Claims 1 - 7 , whereby the fiber-matrix composite protector comprises several layers. Energy storage device according to Claim 9 , wherein at least one of the plurality of layers is a metal plate or a metal mesh, for example made of steel or copper. Energy storage device according to one of the preceding claims, wherein the protective structure and/or the fiber-matrix composite protector further comprises a flame retardant, such as a plate of refractory material such as mica. Energy storage device according to one of the preceding claims, wherein the protective structure and/or the fiber-matrix composite protector has connecting elements which are preferably selected from the group consisting of retainers, embossments, ribs, through holes and blind holes. A fiber-matrix composite protector as defined in any preceding claim. Fiber-matrix semi-finished product for the production of a fiber-matrix composite protector according to Claim 13 , comprising a curable resin composition, and a fiber material with long and/or continuous fibers at least partially, preferably completely, embedded in the curable resin composition, wherein the carbon content of the curable resin composition is ≥ 50 wt.%, preferably ≥ 70 wt.%. Use of a matrix material with a carbon content ≥ 50 wt.% in a fiber-matrix composite protector to improve fire protection properties.