WO2024234687A1 - Energy storage apparatus and energy storage system - Google Patents

Abstract

The embodiments of the present application provide an energy storage apparatus and an energy storage system. The energy storage apparatus comprises: a liquid collecting box, a battery capsule, a battery, and a spraying apparatus, wherein: the battery capsule is used for accommodating a battery, the battery capsule is filled with a first cooling medium, and the first cooling medium is used for cooling the battery; the liquid collecting box is used for accommodating the battery capsule; and the spraying apparatus is located above the top surface of the battery capsule, and the spraying apparatus is used for spraying a second cooling medium onto the outside of the top surface of the battery capsule. The energy storage apparatus and energy storage system provided in the embodiments of the present application enhance the heat dissipation effect and temperature uniformity of the battery, and especially can effectively solve the problem of high-temperature hot spots on a tab.

Description

Energy storage device and energy storage system

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on May 16, 2023, with application number 202310555865.3 and application name “A Energy Storage Device and Energy Storage System”, the entire contents of which are incorporated by reference into this application.

Technical Field

The embodiments of the present application relate to the field of energy technology, and more specifically to an energy storage device and an energy storage system.

Background Art

Replacing traditional fossil energy with new energy is the key to achieving the "dual carbon" goal. Energy transformation has changed the traditional energy structure and promoted the rapid development of electric vehicles and energy storage industries. However, the charging and discharging efficiency, capacity, safety and life of lithium batteries are greatly affected by temperature. Too high or too low temperature or large temperature differences between battery packs will directly affect their performance, causing the battery system to fail prematurely and even cause a series of accidents such as fire and explosion. In order to improve the performance and safety of battery packs, batteries need to be equipped with a thermal management system.

At present, indirect contact liquid cooling (i.e. cold plate liquid cooling) is often used to cool batteries, that is, the liquid cooling plate is attached to the wall of the battery module through a heat-conducting medium, and the heat generated by the battery is transferred to the cooling medium inside the liquid cooling plate through the heat-conducting medium, and then the heat is taken away by the flowing cooling medium. When using indirect contact liquid cooling to cool the battery, there is a large heat transfer resistance between the battery module and the liquid cooling plate, and the heat exchange area between the battery module and the liquid cooling plate is limited, and it is impossible to directly cool high-heating parts such as the battery tabs, resulting in high battery tab temperatures and poor overall battery temperature uniformity.

Summary of the invention

The embodiments of the present application provide an energy storage device and an energy storage system, which can improve the heat dissipation effect and temperature uniformity of the battery.

In a first aspect, an energy storage device is provided, comprising a liquid collecting tank, a battery capsule, a battery and a spraying device, wherein: the liquid collecting tank is used to accommodate the battery capsule; the battery capsule is used to accommodate the battery, the battery capsule is filled with a first cooling medium, and the first cooling medium is used to cool the battery; the spraying device is located above the top surface of the battery capsule, and the spraying device is used to spray a second cooling medium onto the outer surface of the top surface of the battery capsule.

In the embodiment of the present application, when the battery generates heat, the heat can be transferred to the first cooling medium in direct contact with the battery. After the first cooling medium absorbs the heat generated by the battery, it transfers the heat generated by the battery to the battery capsule by heat conduction, heat convection or boiling heat exchange. The battery capsule and the second cooling medium sprayed by the spraying device perform secondary heat exchange by convection heat exchange, and the heat can be carried out of the collecting tank by the flowing second cooling medium. On the one hand, the battery and the first cooling medium exchange heat by direct contact, which has a small heat transfer resistance, and thus can effectively improve the heat dissipation effect of the battery; on the other hand, the first cooling medium has a large contact area with the battery and can contact the parts with higher heat generation (such as the battery tabs). By increasing the heat exchange area, the temperature uniformity of the battery can be improved.

In combination with the first aspect, in certain implementations of the first aspect, the liquid collecting tank includes a top surface, a side surface, and a bottom surface, and the side surface of the liquid collecting tank is provided with at least one liquid inlet and at least one liquid outlet, the liquid inlet is connected to the spray device, and the second cooling medium flows into the spray device through the liquid inlet; the second cooling medium flows out of the liquid collecting tank through the liquid outlet.

In the embodiment of the present application, the second cooling medium flows into the liquid collecting tank from the liquid inlet, exchanges heat with the battery capsule, and then flows out from the liquid outlet of the liquid collecting tank. In other words, the second cooling medium circulates. Therefore, the heat can be taken out of the liquid collecting tank through the circulating flow of the second cooling medium, thereby achieving the purpose of heat dissipation of the battery.

In combination with the first aspect, in certain implementations of the first aspect, the liquid outlet is higher than the bottom surface of the battery capsule and lower than the top surface of the battery capsule. That is, the lowest point of the liquid outlet is higher than the bottom surface of the battery capsule, and the highest point of the liquid outlet is lower than the top surface of the battery capsule.

In the embodiment of the present application, by setting the liquid outlet higher than the bottom surface of the battery capsule and lower than the top surface of the battery capsule, the second cooling medium can partially or completely immerse the side of the battery capsule. Therefore, when the battery is running and generating heat, the first cooling medium around it can absorb the heat generated by the battery and conduct it to the outer surface of the battery capsule through the first cooling medium; the second cooling medium is sprayed out by the spray device located above the top surface of the battery capsule, and the top surface of the battery capsule is cooled by jet flow, and then the second cooling medium flows to the side of the battery capsule. The side of the battery capsule can be cooled by falling film or immersion, and finally the heat is taken out of the liquid collecting tank by the circulation flow of the second cooling medium, so as to achieve Continuous heat dissipation of the battery.

In some embodiments, the distance between the lowest point of the liquid outlet and the bottom surface of the battery capsule is less than a first threshold value, and the first threshold value can be set according to the bottom wall thickness of the liquid collecting tank.

In this case, it can be considered that there is no or only a small amount of the second cooling medium in contact with the side of the battery capsule. Therefore, when the battery is running and generating heat, the first cooling medium around it can absorb the heat generated by the battery and conduct it to the outer surface of the battery capsule through the first cooling medium; the second cooling medium is sprayed out by the spray device located above the top surface of the battery capsule, and cools the top surface of the battery capsule by jet mode, and then the second cooling medium flows to the side of the battery capsule, and falls under the action of gravity, and takes away the heat by convection heat exchange with the side of the battery capsule. This heat dissipation method of top jet and side falling film cooling can effectively improve the convection heat transfer coefficient between the second cooling medium and the outer surface of the battery capsule, thereby improving the overall heat dissipation effect of the battery.

In other embodiments, the lowest point of the liquid outlet is higher than the side surface of the battery capsule and lower than the top surface of the battery capsule.

In this case, it can be considered that the side of the battery capsule is immersed in the second cooling medium. Therefore, when the battery is running and generating heat, the first cooling medium around it absorbs the heat generated by the battery and conducts it to the outer surface of the battery capsule through the first cooling medium; the second cooling medium is sprayed by the spray device located above the top surface of the battery capsule, and the top surface of the battery capsule is cooled by the jet method, and then the second cooling medium flows to the side of the battery capsule. After the second cooling medium is injected for a period of time, the side of the battery capsule will be immersed in the second cooling medium, so that the heat dissipation method of top surface jet and side immersion can be realized, and the heat is taken out of the collecting tank through the circulation flow of the second cooling medium, so as to achieve continuous heat dissipation of the battery.

In combination with the first aspect, in certain implementations of the first aspect, the liquid outlet is higher than the top surface of the battery capsule. That is, the top surface of the battery capsule is located between the highest point of the liquid outlet and the lowest point of the liquid outlet. In this case, it can be considered that the battery capsule is completely immersed in the second cooling medium, that is, the top surface and side surfaces of the battery capsule are immersed in the second cooling medium.

In the embodiment of the present application, by setting the height of the liquid outlet higher than the height of the top surface of the battery capsule, the second cooling medium can completely immerse the battery capsule. Therefore, when the battery is running and generating heat, the first cooling medium around it absorbs the heat generated by the battery and conducts it to the outer surface of the battery capsule through the first cooling medium; the second cooling medium is sprayed out by the spray device located above the top surface of the battery capsule, and the top surface of the battery capsule is cooled by a jet, and then the second cooling medium flows to the side of the battery capsule. After the second cooling medium is injected for a period of time, the battery capsule will be completely immersed in the second cooling medium, so that the heat dissipation method of immersion of the top surface and the side surface can be realized, and the heat is taken out of the liquid collection tank through the circulation flow of the second cooling medium, so as to achieve continuous heat dissipation of the battery.

In combination with the first aspect, in some implementations of the first aspect, the inner surface of the battery capsule is provided with heat dissipation fins, and the heat dissipation fins are used to increase the contact area between the first cooling medium and the inner surface of the battery capsule.

In the embodiment of the present application, heat dissipation fins are arranged on the inner surface of the battery capsule to increase the contact area between the first cooling medium and the inner surface of the battery capsule, thereby enhancing the heat transfer effect between the first cooling medium and the outer surface of the battery capsule and accelerating the cooling of the first cooling medium.

In a possible implementation manner, the top surface of the battery capsule is an arc surface, and the side surface of the battery capsule is perpendicular to the bottom surface of the battery capsule.

It should be understood that when the top surface of the battery capsule is set as an arc surface and the side surface of the battery capsule is perpendicular to the bottom surface of the battery capsule, the spray device can spray the second cooling medium along the arc top surface of the battery capsule, that is, cool the top surface of the battery capsule by jetting, and then the second cooling medium will flow to the side of the battery capsule, and flow down along the side of the battery capsule under the action of gravity, that is, cool the side of the battery capsule by side falling film. Specifically, by setting the top surface of the battery capsule as an arc surface, a certain space can be reserved for the gas phase first cooling medium; under the action of jet impact, the top surface of the battery capsule exchanges heat with the fluid at a higher convection heat transfer coefficient to achieve a better heat dissipation effect; under the action of falling film cooling, the side surface of the battery capsule exchanges heat at a higher convection heat transfer coefficient to achieve a better heat dissipation effect. In addition, the distance between the side of the battery capsule and the battery is relatively small, the space occupied by the battery capsule is relatively small, and the space utilization rate is high.

In another possible implementation, the top surface and side surfaces of the battery capsule are both arc surfaces.

It should be understood that when the top and side surfaces of the battery capsule are both arc surfaces, the spray device can spray the second cooling medium along the arc top and side surfaces of the battery capsule, that is, cool the top and side surfaces of the battery capsule by jetting. The arc-shaped top and side surfaces can increase the jet area, and the fluid flow rate on the top and side surfaces of the battery capsule is faster, so that the fluid and the outer surface of the battery capsule can exchange heat with a higher convection heat transfer coefficient, achieving a better heat dissipation effect. In addition, since the top and side surfaces of the battery capsule are both arc surfaces, the height of the spray device will increase, and the distance between the side surface of the battery capsule and the battery is relatively large, so the space occupied by the battery capsule is relatively large.

In yet another possible implementation, the battery capsule is a cubic structure or a rectangular parallelepiped structure.

It should be understood that when the battery capsule is set to a cubic structure or a rectangular structure, the second cooling medium sprayed by the spray device can flow downward along the cubic or rectangular battery capsule and flow through the top and side surfaces of the battery capsule, thereby transferring the second cooling medium to the outer surface of the battery capsule. When the second cooling medium flows along the battery capsule, the heat exchange area between the second cooling medium and the battery capsule is increased compared with the first two implementations, which can ensure the heat exchange effect to a certain extent.

In combination with the first aspect, in certain implementations of the first aspect, the battery is partially or completely immersed in the first cooling medium.

In the embodiment of the present application, the first cooling medium can immerse the battery tab, thereby dissipating the heat of the battery tab, solving the problem of ineffective cooling of the battery tab and avoiding excessive temperature difference between the battery tab and the core.

In combination with the first aspect, in some implementations of the first aspect, the battery capsule is a fully sealed structure.

In the embodiment of the present application, by setting the battery capsule as a fully sealed structure, the airtightness of the cavity can be ensured, and the risk of gas phase working fluid leakage can be reduced. At the same time, by means of top jet and side falling film, the condensation of the first cooling medium can be accelerated, and the battery can be prevented from being squeezed and deformed due to excessive air pressure inside the battery capsule, thereby solving the problem of difficult to control pressure balance inside the battery capsule.

In combination with the first aspect, in certain implementations of the first aspect, the battery includes but is not limited to any of the following types: a square battery, a cylindrical battery, and a soft-pack battery.

In the embodiment of the present application, the first cooling medium can transfer the heat generated by the battery to the inner surface of the battery capsule by heat conduction, heat convection or boiling heat exchange, the inner surface of the battery capsule transfers the heat to the outer surface of the battery capsule by heat conduction, the outer surface of the battery capsule contacts the sprayed second cooling medium, transfers the heat to the second cooling medium by convection heat exchange, and is then carried out of the collecting tank by the circulating second cooling medium, so as to achieve the purpose of reducing the battery temperature.

In combination with the first aspect, in certain implementations of the first aspect, the first cooling medium is an insulating cooling medium, for example, an oil cooling medium or a fluorinated liquid cooling medium, and the second cooling medium includes any one of the following: ethylene glycol aqueous solution, nanofluid, phase change emulsion.

It should be noted that, since the first cooling medium is in direct contact with the battery, the first cooling medium is an insulating cooling medium. That is to say, the first cooling medium can be a single-phase insulating cooling medium or a two-phase insulating cooling medium. The second cooling medium can include all types of cooling media, that is, the second cooling medium can be an insulating cooling medium or a non-insulating cooling medium. Exemplarily, the second cooling medium can be: oils, fluorinated liquids, ethylene glycol aqueous solutions, nanofluids, phase change emulsions, etc., which are not limited in this application.

In a possible implementation, the first cooling medium may be a single-phase insulating cooling medium (e.g., oil). The single-phase insulating cooling medium may transfer the heat of the battery to the inner surface of the battery capsule by heat conduction and heat convection, and the inner surface of the battery capsule transfers the heat to the outer surface of the battery capsule by heat conduction. The outer surface of the battery capsule contacts the second cooling medium, transfers the heat to the second cooling medium by convection heat exchange, and is then carried out of the collecting tank by the circulating second cooling medium.

In another possible implementation, the first cooling medium can be a two-phase insulating cooling medium (for example, fluorinated liquid). The heat generated by the battery can be taken away by heat conduction, heat convection and boiling heat exchange between the two-phase insulating cooling medium and the battery surface. Specifically, when the temperature of the battery is low in the early and middle stages of charge and discharge, the first cooling medium absorbs the heat generated by the battery by heat conduction and heat convection; when the battery temperature reaches the phase change temperature of the first cooling medium, the first cooling medium boils and absorbs a large amount of heat generated by the battery; the gas phase first cooling medium moves to the top surface of the battery capsule under the action of molecular thermal motion, and exchanges heat with the top surface of the battery capsule by heat conduction and heat convection; the top surface of the battery capsule exchanges heat with the second cooling medium sprayed by the spray device by convection heat exchange, indirectly absorbing the heat of the first cooling medium, and then taking the heat out of the collecting tank by circulating flow; the cooled first cooling medium condenses and flows back into the battery capsule, and this cycle is repeated to achieve efficient heat dissipation of the battery.

In combination with the first aspect, in some implementations of the first aspect, the spray device is fixed to the outside of the top surface of the battery capsule, or the spray device is fixed to the inside of the top surface of the liquid collecting tank.

In a possible implementation, the spray device includes a main pipeline, and the main pipeline is provided with a plurality of spray points, including a first spray point, and the first spray point is provided with a first branch pipeline and a second branch pipeline, the first branch pipeline can be provided along a first direction, and the second branch pipeline can be provided along a second direction, the first direction and the second direction are oriented toward the top surface of the battery capsule, and the first direction and the second direction are provided at an angle. It should be understood that the first spray point can be a point located on the main pipeline, or a point located on two walls of the main pipeline.

In another possible implementation, the spray device includes a main pipeline, and the main pipeline is provided with a plurality of spray points, including a first spray point, and the first spray point is provided with a first branch pipeline and a second branch pipeline, and the first branch pipeline and the second branch pipeline can be arranged along a third direction, and the third direction is parallel to the top surface of the battery capsule. It should be understood that the first spray point can be a point located on the main pipeline, or can be a point located on two walls of the main pipeline.

In a second aspect, an energy storage system is provided, comprising: the energy storage device as described in the first aspect and any one of the first aspects; and a heat dissipation circuit, wherein the heat dissipation circuit is used to cool the second cooling medium.

In a possible implementation, the heat dissipation circuit includes a valve, a water pump, a flow meter, a radiator and a piping system. Used to control the flow of the second cooling medium in the energy storage system, the water pump is used to provide the circulation power of the second cooling medium in the energy storage system, the flow meter is used to measure the flow of the second cooling medium in the energy storage system, the radiator is used to dissipate heat for the second cooling medium, and the piping system is used to connect the valve, the water pump, the flow meter and the radiator.

In an embodiment of the present application, when the battery generates heat, the heat can be transferred to the first cooling medium that is in direct contact with the battery. The first cooling medium can transfer the heat of the battery to the battery capsule. The spray device can spray the second cooling medium into the battery capsule, thereby transferring the heat to the second cooling medium, which dissipates the heat. The second cooling medium can circulate to the outside of the liquid collection tank and dissipate the heat of the second cooling medium through the radiator, thereby dissipating the heat generated by the battery into the atmospheric environment.

In a possible implementation, in response to the temperature of the battery being higher than a first threshold, the energy storage system performs at least one of the following operations: increasing a valve opening, increasing a water pump power, and increasing a radiator operating power.

In this implementation, when the battery temperature is higher than a certain threshold, the heat dissipation capacity of the energy storage system needs to be enhanced. Therefore, the flow rate of the second cooling medium can be increased by increasing the opening of the valve, or the water pump power can be increased to increase the circulation speed of the second cooling medium, or the radiator operating power can be increased to enhance the heat dissipation efficiency of the second cooling medium.

In another possible implementation, in response to the temperature of the battery being lower than a first threshold, the energy storage system performs at least one of the following operations: reducing a valve opening, reducing a water pump power, and reducing a radiator operating power.

In this implementation, when the battery temperature is lower than a certain threshold, the heat dissipation capacity of the energy storage system needs to be weakened to reduce system power consumption. The flow rate of the second cooling medium can be reduced by reducing the opening of the valve, or the water pump power can be reduced to reduce the circulation speed of the second cooling medium, or the radiator operating power can be reduced to reduce the heat dissipation efficiency of the second cooling medium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of an energy storage device provided in an embodiment of the present application.

FIG. 2 is a schematic diagram of the internal structure of a battery capsule provided in an embodiment of the present application.

FIG3 is a schematic diagram of the structure of another energy storage device provided in an embodiment of the present application.

FIG. 4 is a schematic diagram of the structure of another energy storage device provided in an embodiment of the present application.

FIG. 5 is a schematic diagram of the structure of another energy storage device provided in an embodiment of the present application.

FIG6 is a schematic diagram of the structure of another energy storage device provided in an embodiment of the present application.

FIG. 7 is a schematic diagram of the structure of another energy storage device provided in an embodiment of the present application.

FIG8 is a schematic diagram of the structure of another energy storage device provided in an embodiment of the present application.

FIG. 9 is a schematic diagram of the structure of a spray device provided in an embodiment of the present application.

FIG. 10 is a schematic diagram of the structure of another spray device provided in an embodiment of the present application.

FIG. 11 is a schematic diagram of the structure of an energy storage system provided in an embodiment of the present application.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

In order to facilitate understanding of the embodiments of the present application, the following points are explained before introducing the embodiments of the present application.

In the embodiments of the present application, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may sensibly or implicitly include one or more features. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two, "at least one" and "one or more" refer to one, two or more. The singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear indication to the contrary in the context.

References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear at different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

In the description of the embodiments of the present application, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "vertical", etc. are defined relative to the directions or positions of the components schematically placed in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, rather than indicating or implying that the device or component referred to must have a specific direction, or be constructed in a specific direction. The manufacture and operation of the present invention may vary according to the changes in the orientation of the components in the drawings, and therefore cannot be understood as a limitation to the present application.

In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

The embodiment of the present application defines the coordinate system of the accompanying drawings. In this coordinate system, the x-direction, the y-direction and the z-direction intersect each other. Among them, the x-direction and the y-direction are set at an angle, the y-direction and the z-direction are set at an angle, and the z-direction and the x-direction are set at an angle. The angle can be approximately 90°, for example, it can be 85°, 90°, 95°, etc., and the present application does not limit this. For ease of description and understanding, the embodiment of the present application is described by taking the x-direction, the y-direction and the z-direction as examples of being perpendicular to each other. For example, the x-direction and the y-direction can be parallel to the ground, and the z-direction can be perpendicular to the ground.

Replacing traditional fossil energy with new energy is the key to achieving the "dual carbon" goal. Energy transformation has changed the traditional energy structure and promoted the rapid development of electric vehicles and energy storage industries. However, the charging and discharging efficiency, capacity, safety and life of lithium batteries are greatly affected by temperature. Too high or too low temperature or large temperature differences between battery packs will directly affect their performance, causing the battery system to fail prematurely and even cause a series of accidents such as fire and explosion. In order to improve the performance and safety of the battery pack, the battery pack needs to be equipped with a thermal management system.

The main ways of heat transfer include heat conduction and convection. Among them, heat conduction refers to the way of heat transfer along a solid object, where heat is transferred from the higher temperature part of the object to the lower temperature part along the object. Convection heat transfer refers to the way heat is transferred through the flow of heat in gas or liquid.

Common convective heat transfer methods include jet heat transfer and boiling heat transfer. Jet refers to a flow mode in which liquid is ejected from a nozzle or orifice and escapes the constraints of the solid boundary. Jet heat transfer refers to the heat transfer of liquid by jet. Jet heat transfer is a type of convective heat transfer. The heat transfer capacity of jet heat transfer. The heat transfer process when the boiling heat transfer liquid boils on the heating surface is a two-phase flow heat transfer with phase change characteristics. Boiling heat transfer is a type of convective heat transfer. The heat transfer coefficient of boiling heat transfer is large and the heat transfer capacity is strong. Falling film refers to the flow of liquid from top to bottom in a film shape along the wall of the container under the action of gravity. The liquid can absorb heat from the wall of the container during the falling film process.

At present, indirect contact liquid cooling (i.e. cold plate liquid cooling) is often used to cool batteries, that is, the liquid cold plate is attached to the wall of the battery module through a heat-conducting medium, and the heat generated by the battery is transferred to the cooling medium inside the cold plate through the heat-conducting medium, and then the heat is taken away by the flowing cooling medium. When using indirect contact liquid cooling for heat dissipation, there is a large heat transfer resistance between the battery module and the liquid cold plate, resulting in limited heat dissipation effect, and the heat exchange area between the battery module and the liquid cold plate is limited, and it is impossible to directly cool high-heating parts such as the battery tabs, resulting in high battery tab temperatures and poor overall battery temperature uniformity.

Immersion liquid cooling is a new type of liquid cooling technology in recent years. It refers to immersing part or all of the battery in an insulating cooling medium to remove the heat generated by the battery through convection heat transfer or two-phase boiling heat transfer. Immersion liquid cooling can achieve better heat dissipation effects by virtue of its larger heat transfer area and higher heat transfer coefficient during two-phase boiling heat transfer. On the one hand, immersion liquid cooling can increase the energy density of the battery by reducing the gap between the batteries, and on the other hand, it can increase the temperature uniformity of the battery by increasing the heat exchange area between the coolant and the battery.

Immersion liquid cooling includes single-phase immersion and two-phase immersion. In a single-phase immersion (e.g., oil immersion) cooling system, the battery and the coolant mainly dissipate heat through heat conduction and convection heat transfer; in a two-phase immersion (e.g., fluorinated liquid immersion) cooling system, the battery and the coolant mainly remove the heat of the battery through boiling heat transfer. The convection heat transfer coefficient during boiling heat transfer is greatly improved, so the heat dissipation effect is significantly improved compared to single-phase convection. In addition, the viscosity of the insulating cooling medium in single-phase immersion is relatively large, and the pump power consumption of driving the insulating cooling medium is relatively large; however, the system complexity is higher in two-phase immersion, and there is a risk of leakage after the working medium is vaporized, as well as problems such as pressure balance control in the cavity.

Therefore, the embodiments of the present application provide an energy storage device and an energy storage system to solve the above problems.

FIG1 is a schematic diagram of the structure of an energy storage device provided in an embodiment of the present application.

The energy storage device 100 may include a liquid collecting tank 110, a battery capsule 120, a battery 130 and a spraying device 140, wherein: the battery capsule 120 includes a top surface, a side surface and a bottom surface, the battery capsule 120 is used to accommodate the battery 130, the battery capsule 120 is filled with a first cooling medium, and the first cooling medium is used to cool the battery 130; the liquid collecting tank 110 is used to accommodate the battery capsule 120; the spraying device 140 is located above the top surface of the battery capsule 120, and the spraying device 140 is used to spray a second cooling medium onto the outer surface of the top surface of the battery capsule 120.

It should be understood that the battery capsule 120 is filled with a first cooling medium, and the first cooling medium can partially or completely immerse the battery 130, so that the battery 130 can be cooled by the first cooling medium, that is, the battery 130 can be cooled by immersion liquid cooling. The battery 130 can also be replaced by other electronic devices, including but not limited to the following electronic devices: servers, chips, power devices (such as power conversion systems (PCS)).

It should be noted that, since the first cooling medium is in direct contact with the battery 130, the first cooling medium is an insulating cooling medium. That is, the first cooling medium can be a single-phase insulating cooling medium (for example, an oil cooling medium) or a two-phase insulating cooling medium (for example, a fluorinated liquid cooling medium). The second cooling medium can include all types of cooling media, that is, the second cooling medium can be an insulating cooling medium or a non-insulating cooling medium. Exemplarily, the second cooling medium can be: oils, fluorinated liquids, ethylene glycol aqueous solutions, nanofluids, phase change emulsions, etc., which are not limited in this application.

It should be understood that the first cooling medium can transfer the heat generated by the battery 130 to the inner surface of the battery capsule 120 by heat conduction, heat convection or boiling heat exchange, and the inner surface of the battery capsule 120 transfers the heat to the outer surface of the battery capsule 120 by heat conduction. The outer surface of the battery capsule 120 contacts the sprayed second cooling medium, transfers the heat to the second cooling medium by convection heat exchange, and is then taken out of the collecting tank 110 by the circulating second cooling medium, so as to achieve the purpose of reducing the temperature of the battery 130. It should be noted that the energy storage device 100 provided in the embodiment of the present application, on the one hand, the battery 130 and the first cooling medium exchange heat by direct contact, and has a small heat transfer resistance, so it can effectively improve the heat dissipation effect of the battery 130; on the other hand, the first cooling medium has a large contact area with the battery 130, and can contact the parts with higher heat generation (such as the battery tabs), and improve the temperature uniformity of the battery 130 by increasing the heat exchange area.

In some embodiments, the first cooling medium may be a single-phase insulating cooling medium (e.g., oil). The single-phase insulating cooling medium may transfer the heat of the battery 130 to the inner surface of the battery capsule 120 by heat conduction and heat convection, and the inner surface of the battery capsule 120 transfers the heat to the outer surface of the battery capsule 120 by heat conduction. The outer surface of the battery capsule 120 contacts the second cooling medium sprayed by the spray device 140, transfers the heat to the second cooling medium by convection heat exchange, and is then carried out of the collecting tank 110 by the circulating second cooling medium.

In other embodiments, the first cooling medium may be a two-phase insulating cooling medium (e.g., fluorinated liquid). The heat generated by the battery 130 can be taken away by heat conduction, heat convection, and boiling heat exchange between the two-phase insulating cooling medium and the battery surface. Specifically, when the temperature of the battery 130 is low in the early and middle stages of charge and discharge, the first cooling medium absorbs the heat generated by the battery 130 by heat conduction and heat convection; when the temperature of the battery 130 reaches the phase change temperature of the first cooling medium, the first cooling medium boils and absorbs a large amount of heat generated by the battery 130; the gas phase first cooling medium moves to the top surface of the battery capsule 120 under the action of molecular thermal motion, and exchanges heat with the top surface of the battery capsule 120 by heat conduction and heat convection; the top surface of the battery capsule 120 exchanges heat with the second cooling medium sprayed by the spray device 140 by convection heat exchange, indirectly absorbing the heat of the first cooling medium, and then taking the heat out of the collecting tank 110 by circulating flow; the cooled first cooling medium condenses and flows back into the battery capsule 120, and such a cycle is repeated to achieve efficient heat dissipation of the battery.

For example, the first cooling medium is a fluorinated liquid. When the temperature of the battery 130 reaches the phase change temperature of the fluorinated liquid, the fluorinated liquid continuously absorbs the heat of the battery 130, so that the fluorinated liquid can undergo a phase change (i.e., vaporization). During the vaporization process, on the one hand, the fluorinated liquid can absorb a large amount of heat, and on the other hand, the heat transfer coefficient between the fluorinated liquid and the surface of the battery 130 is significantly improved, so that the heat generated by the battery 130 can be taken away more quickly, thereby improving the heat dissipation efficiency of the battery 130. After the fluorinated liquid absorbs heat and becomes gas, it floats to the top surface of the battery capsule 120 by molecular thermal motion, and then exchanges heat with the top surface of the battery capsule 120 by thermal conduction and thermal convection. The top surface of the battery capsule 120 and the second cooling medium sprayed by the spray device 140 then indirectly take away the heat in the first cooling medium by convection heat exchange. After the first cooling medium is cooled, it condenses into liquid and flows back into the battery capsule 120 under the action of gravity.

It should be noted that the first cooling medium can completely immerse the battery 130, that is, the liquid level of the first cooling medium can be higher than the height of the battery 130. The first cooling medium can immerse the battery tabs, thereby dissipating the heat of the battery tabs, solving the problem of ineffective cooling of the battery tabs and avoiding excessive temperature difference between the battery tabs and the core.

In some embodiments, as shown in FIG. 2 , FIG. 2 shows the internal structure of a battery capsule. The battery capsule 120 may include at least one battery 130 or multiple closely arranged batteries 130. There is a gap between two adjacent rows of batteries, and the gap may be filled with a first cooling medium. The battery 130 includes but is not limited to any of the following types: square batteries, cylindrical batteries, and soft-pack batteries. It should be understood that in the embodiments of the present application, the spacing between different single cells is greatly reduced compared to the indirect contact cooling of the prior art, and the energy density and power density of the battery pack are significantly improved.

In some embodiments, the battery capsule 120 is a fully sealed structure. By setting the battery capsule 120 to a fully sealed structure, the airtightness of the cavity can be ensured and the risk of gas phase working fluid leakage can be reduced. At the same time, the condensation of the first cooling medium can be accelerated by the top jet and side falling film, avoiding the battery extrusion and deformation caused by excessive air pressure inside the battery capsule 120, and solving the problem of difficult control of pressure balance inside the battery capsule 120.

In the embodiment of the present application, there is no limitation on the number of battery capsules 120 and batteries 130. The present application may include one or more battery capsules and one or more batteries. In practical applications, the number of battery capsules may be adjusted according to the number of batteries, that is, the batteries may be placed in one capsule or in multiple different capsules.

Optionally, as shown in FIG. 2 , the inner surface of the battery capsule 120 may be provided with heat dissipation fins 121, and the heat dissipation fins 121 may be used to increase the contact area between the first cooling medium and the inner wall of the battery capsule 120. Exemplarily, the battery capsule 120 may be a rectangular parallelepiped. At least one inner wall of the cuboid is provided with heat dissipation fins 121. Arranging the heat dissipation fins 121 on the inner surface of the battery capsule 120 can increase the contact area between the first cooling medium and the inner surface of the battery capsule 120, thereby enhancing the heat transfer effect between the first cooling medium and the battery capsule 120 and accelerating the cooling of the first cooling medium.

In some embodiments, the liquid collecting tank 110 includes a top surface, a side surface, and a bottom surface, and at least one liquid inlet and at least one liquid outlet are provided on the side surface of the liquid collecting tank 110. Exemplarily, a liquid inlet 150 and a liquid outlet 160 are provided on the side surface of the liquid collecting tank 110. The liquid inlet 150 is connected to the spray device 140, and the second cooling medium flows into the spray device 140 through the liquid inlet 150; the second cooling medium flows out of the liquid collecting tank 110 through the liquid outlet 160.

In some embodiments, the liquid inlet 150 may be connected to the spray device 140 located above the top surface of the battery capsule 120. It should be noted that the liquid outlet 160 is higher than the bottom surface of the battery capsule 120 and lower than the top surface of the battery capsule 120, or the liquid outlet 160 is higher than the top surface of the battery capsule 120.

Exemplarily, the position of the liquid outlet 160 may include the following three configurations: By changing the height of the liquid outlet 160 , various heat dissipation modes of the battery 130 may be achieved.

In the first configuration, the position of the liquid outlet 160 may be as shown in FIG3 , and the distance between the lowest point of the liquid outlet 160 and the bottom surface of the battery capsule 120 is less than a first threshold value, which may be set according to the bottom wall thickness of the liquid collecting tank 110. In this case, it can be considered that the side surface of the battery capsule 120 is not immersed in the second cooling medium.

It should be understood that the second cooling medium can enter the spray device 140 from the liquid inlet 150, and the spray device 140 can spray the second cooling medium to the battery capsule 120. The second cooling medium flows through the top surface and the side surface of the battery capsule 120 in sequence and then flows out directly from the liquid outlet 160, thereby realizing the heat dissipation method of top surface jet and side falling film.

Among them, the first cooling medium liquid level 122 can be as shown in Figure 3, that is, the height of the first cooling medium is higher than the height of the battery 130, that is, the first cooling medium completely immerses the battery 130; the second cooling medium liquid level 111 can be as shown in Figure 3. Since the position of the second cooling medium outlet 160 is lower, the second cooling medium liquid level 111 is lower, and the second cooling medium does not immerse the side of the battery capsule 120.

In this arrangement, when the battery 130 generates heat, the first cooling medium around it absorbs the heat generated by the battery 130 and conducts it to the outer surface of the battery capsule 120 through the first cooling medium; the second cooling medium is sprayed by the spray device 140 located above the top surface of the battery capsule 120, and cools the top surface of the battery capsule 120 by jet flow, and then the second cooling medium flows to the side of the battery capsule 120, and falls under the action of gravity, and takes away the heat by convection heat exchange with the side of the battery capsule 120. This heat dissipation method of top jet flow and side falling film can effectively improve the convection heat transfer coefficient between the second cooling medium and the outer surface of the battery capsule 120, thereby improving the overall heat dissipation effect of the battery.

In the second configuration, the position of the liquid outlet 160 may be as shown in FIG4 , where the lowest point of the liquid outlet 160 is higher than the side surface of the battery capsule 120 and lower than the top surface of the battery capsule 120. In this case, it can be considered that the side surface of the battery capsule 120 is partially or completely immersed in the second cooling medium.

It should be understood that the second cooling medium enters the spray device 140 from the liquid inlet 150, and the spray device 140 sprays the second cooling medium to the battery capsule 120. After the second cooling medium is injected into the collecting tank 110 for a period of time, the side of the battery capsule 120 will be immersed in the second cooling medium, and the top wall of the battery capsule 120 will exchange heat through the jet method, that is, the heat dissipation method of top jet and side immersion can be realized.

Among them, the first cooling medium liquid level 122 can be as shown in Figure 4, that is, the height of the first cooling medium is higher than the height of the battery 130, that is, the first cooling medium completely immerses the battery 130; the second cooling medium liquid level 111 can be as shown in Figure 4, and the second cooling medium can partially or completely immerse the side of the battery capsule 120.

In this arrangement, when the battery 130 generates heat during operation, the first cooling medium around it absorbs the heat generated by the battery 130 and conducts it to the outer surface of the battery capsule 120 through the first cooling medium; the second cooling medium is sprayed by the spray device 140 located on the top surface of the battery capsule 120, and cools the top surface of the battery capsule 120 by jetting, and then the second cooling medium flows to the side of the battery capsule 120. After the second cooling medium is injected for a period of time, the side of the battery capsule 120 will be immersed in the second cooling medium, so that the heat dissipation method of top jetting and side immersion can be realized, and the heat is taken out of the collecting tank 110 by the circulation flow of the second cooling medium, so as to achieve continuous heat dissipation of the battery 130. However, compared with the first heat dissipation method, the heat dissipation method of top jetting and side immersion has a lower heat transfer coefficient on the side due to the fact that the side of the battery capsule 120 is partially or completely immersed in the second cooling medium, and the fluid flow rate on the side is low. Therefore, compared with the first heat dissipation method, the heat transfer effect on the side of the battery capsule is relatively poor, and the heat dissipation efficiency of the battery is relatively low.

In the third arrangement, the position of the liquid outlet 160 may be as shown in FIG5 , wherein the liquid outlet 160 is higher than the top surface of the battery capsule 120, that is, the top surface of the battery capsule 120 is located between the highest point of the liquid outlet 160 and the lowest point of the liquid outlet 160. In this case, it can be considered that the battery capsule 120 is completely immersed in the second cooling medium, that is, the top surface and the side surface of the battery capsule 120 are immersed in the second cooling medium.

When the liquid outlet 160 is higher than the top surface of the battery capsule 120, the second cooling medium enters the spray device 140 from the liquid inlet 150 and sprays The shower device 140 sprays the second cooling medium to the battery capsule 120. After the second cooling medium is injected into the collecting tank 110 for a period of time, the battery capsule 120 is completely immersed in the second cooling medium, thereby realizing a heat dissipation mode of immersion of the top surface and the side surface.

Among them, the first cooling medium liquid level 122 can be as shown in Figure 5, that is, the height of the first cooling medium is higher than the height of the battery 130, that is, the first cooling medium completely immerses the battery 130; the second cooling medium liquid level 111 can be as shown in Figure 5, the second cooling medium completely immerses the entire battery capsule 120, that is, the height of the second cooling medium liquid level 111 can be higher than the height of the battery capsule 120.

In this arrangement, when the battery 130 generates heat during operation, the first cooling medium around it absorbs the heat generated by the battery 130 and conducts it to the outer surface of the battery capsule 120 through the first cooling medium; the second cooling medium is sprayed by the spray device 140 located above the top surface of the battery capsule 120, and cools the top surface of the battery capsule 120 by jet flow, and then the second cooling medium flows to the side of the battery capsule 120. After the second cooling medium is injected for a period of time, the battery capsule 120 is completely immersed in the second cooling medium, so that the top and side surface immersion heat dissipation method can be achieved, and the heat is taken out of the collecting tank 110 through the circulation flow of the second cooling medium, so as to achieve continuous heat dissipation of the battery 130. It should be understood that the top and side surface immersion heat dissipation method is relatively poor compared to the first heat dissipation method and the second heat dissipation method, because the top and side surfaces of the battery capsule 120 are completely immersed in the second cooling medium, the fluid flow rate of the top and side surfaces is low, resulting in a low heat transfer coefficient of the top and side surfaces, so the heat transfer effect is relatively poor, and the heat dissipation efficiency of the battery is relatively low.

In some embodiments, the appearance of the battery capsule 120 may be as shown in Figures 6 to 8, which show cross-sectional views of the energy storage device 100 along the yz plane. It should be understood that the top surface of the battery capsule 120 may be configured as an arc surface structure (as shown in Figures 6 and 7) or a flat structure (as shown in Figure 8).

In one example, the top surface of the battery capsule 120 is an arc surface, the side surface of the battery capsule 120 is perpendicular to the bottom surface of the battery capsule 120, and the shape of the battery capsule 120 may be as shown in Figure 6. The heat exchange method between the battery capsule 120 and the second cooling medium may be a top jet and a side falling film method.

It should be understood that in this example, the spray device 140 can spray the second cooling medium along the arc top surface of the battery capsule 120, that is, cool the top surface of the battery capsule 120 by jetting, and then the second cooling medium will flow to the side of the battery capsule 120, and flow down along the side of the battery capsule 120 under the action of gravity, that is, cool the side of the battery capsule 120 by side falling film. Specifically, by setting the top surface of the battery capsule 120 as an arc surface, a certain space can be reserved for the gas phase first cooling medium; under the action of jet impact, the top surface of the battery capsule 120 exchanges heat with the fluid at a higher convection heat transfer coefficient to achieve a better heat dissipation effect; under the action of falling film cooling, the side of the battery capsule 120 exchanges heat at a higher convection heat transfer coefficient to achieve a better heat dissipation effect. In addition, the distance between the side of the battery capsule 120 and the battery is relatively small, the space occupied by the battery capsule 120 is relatively small, and the space utilization rate is high.

In another example, the top and side surfaces of the battery capsule 120 are arc surfaces, and the shape of the battery capsule 120 may be as shown in Figure 7. In Figure 7, the height and spray range of the spray device 140 are increased, and the heat exchange mode between the battery capsule 120 and the second cooling medium is dominated by the jet heat exchange mode.

It should be understood that in this example, the spray device 140 can spray the second cooling medium along the arc top surface and side surface of the battery capsule 120, that is, cool the top surface and side surface of the battery capsule 120 by jetting. The arc-shaped top surface and side surface can increase the jet area, and the fluid flow rate on the top surface and side surface of the battery capsule 120 is faster, so that the fluid and the outer surface of the battery capsule 120 can exchange heat with a higher convection heat transfer coefficient, achieving a better heat dissipation effect. In addition, since the top surface and side surface of the battery capsule 120 are both arc surfaces, the height of the spray device 140 is increased, and the distance between the side surface of the battery capsule 120 and the battery is relatively large, so the space occupied by the battery capsule 120 is relatively large.

In another example, the battery capsule 120 is a cubic structure or a rectangular parallelepiped structure, and the appearance of the battery capsule 120 may be shown in Figure 8. The battery capsule 120 in Figure 8 is a rectangular parallelepiped structure, and the heat exchange area is greatly increased, which helps to enhance the heat exchange effect between the first cooling medium and the second cooling medium.

It should be understood that in this example, the second cooling medium sprayed by the spray device 140 can flow downward along the rectangular battery capsule 120, flowing through the top surface and side surfaces of the battery capsule 120, thereby taking away the heat transferred to the outer surface of the battery capsule 120. When the second cooling medium flows along the battery capsule 120 as shown in FIG8 , compared with the above two methods, the heat exchange area between the second cooling medium and the battery capsule 120 is increased, which can ensure the heat exchange effect to a certain extent.

In some embodiments, the spray device 140 is fixed to the outside of the top surface of the battery capsule 120, or the spray device 140 is fixed to the inside of the top surface of the liquid collecting tank 110. The structural schematic diagram of the spray device 140 can refer to FIG9 and FIG10.

In one example, the structure of the spray device 140 can refer to FIG9 , the spray device 140 includes a main pipe 141, the main pipe 141 is provided with a plurality of spraying points, including a first spraying point, the first spraying point is provided with two branch pipes (recorded as the first branch pipe 142 and the second branch pipe 143), the first branch pipe 142 can be arranged along a first direction, the second branch pipe 143 can be arranged along a second direction, the first direction and the second direction are toward the top surface of the battery capsule 120, and the first direction and the second direction are arranged at an angle. It should be understood that the first spraying point can be a point located on the main pipe, or a point located on two walls of the main pipe.

In another example, the structure of the spray device 140 can refer to FIG10. The spray device 140 includes a main pipeline 141, and a plurality of spray points are arranged on the main pipeline 141, including a first spray point, and two branch pipelines (recorded as a first branch pipeline 142 and a second branch pipeline 143) are arranged on the first spray point. The first branch pipeline 142 and the second branch pipeline 143 can be arranged along a third direction (such as the y direction), and the third direction is parallel to the top surface of the battery capsule 120. It should be understood that the first spray point can be a point located on the main pipeline, or a point located on two walls of the main pipeline.

It should be noted that the spray device shown in FIG. 9 or FIG. 10 can be used in combination with the energy storage device in FIG. 6 to FIG. 8, and this application does not limit this. In some embodiments, the spray device 140 shown in FIG. 9 can be used in combination with the battery capsule 120 shown in FIG. 7 and FIG. 8. In other embodiments, the spray device 140 shown in FIG. 10 can be used in combination with the battery capsule 120 shown in FIG. 8.

FIG. 11 is a schematic diagram of the structure of an energy storage system provided in an embodiment of the present application.

The energy storage system 200 may include the energy storage device 100 and a heat dissipation circuit as shown in FIG. 1 to FIG. 8 . The heat dissipation circuit is used to cool the second cooling medium.

In some embodiments, the heat dissipation circuit includes a valve 210, a water pump 220, a flow meter 230, a radiator 240, and a piping system. The valve 210 is used to control the flow of the second cooling medium in the energy storage system, the water pump 220 is used to provide the circulation power of the second cooling medium in the energy storage system, the flow meter 230 is used to measure the flow of the second cooling medium in the energy storage system, the radiator 240 is used to dissipate heat for the second cooling medium, and the piping system is used to connect the valve 210, the water pump 220, the flow meter 230, and the radiator 240.

It should be understood that the second cooling medium flows out from the liquid outlet 160 after heat exchange with the outer surface of the battery capsule 120. The liquid outlet 160 is connected to the circulating water pump 220 through a pipeline, and a valve 210 is installed in the pipeline to control the flow rate of the second cooling medium in the energy storage system. The flow meter 230 measures the flow rate of the second cooling medium in the energy storage system. The water pump 220 can be connected to the radiator 240 through a pipeline to provide the circulation power of the second cooling medium in the energy storage system; the radiator 240 can be connected to the liquid inlet 150 through a pipeline to cool the second cooling medium. The second cooling medium can eventually dissipate the heat generated by the battery 130 into the atmosphere through the radiator 240, and the second cooling medium cooled by the radiator 240 is circulated to the liquid inlet 150 of the liquid collecting tank 110, thereby completing the entire circulation heat exchange scenario.

In the energy storage system 200, the heat dissipation pathway of the battery 130 is as follows: when the battery 130 generates heat, the heat can be transferred to the first cooling medium in direct contact with the battery 130. The first cooling medium can transfer the heat generated by the battery 130 to the inner surface of the battery capsule 120 by heat conduction, heat convection or boiling heat exchange. The inner surface of the battery capsule 120 transfers the heat to the outer surface of the battery capsule 120 by heat conduction; the outer surface of the battery capsule 120 contacts the second cooling medium sprayed by the spray device 140, transfers the heat to the second cooling medium by convection heat exchange, and is then carried out of the collecting tank 110 by the circulating second cooling medium; the second cooling medium is then dissipated by the radiator 240, so that the heat generated by the battery 130 can be dissipated into the atmosphere.

In some embodiments, in response to the temperature of the battery 130 being higher than the first threshold, the energy storage system performs at least one of the following operations: increasing the opening of the valve 210 , increasing the power of the water pump 220 , and increasing the operating power of the radiator 240 .

In this embodiment, when the temperature of the battery 130 is higher than a certain threshold, the heat dissipation capacity of the energy storage system needs to be enhanced, so the flow rate of the second cooling medium can be increased by increasing the opening of the valve 210, or the power of the water pump 220 can be increased to enhance the circulation speed of the second cooling medium, or the operating power of the radiator 240 can be increased to enhance the heat dissipation efficiency of the second cooling medium.

In other embodiments, in response to the temperature of the battery 130 being lower than a first threshold, the energy storage system performs at least one of the following operations: reducing the opening of the valve 210 , reducing the power of the water pump 220 , and reducing the operating power of the radiator 240 .

In this embodiment, when the temperature of the battery 130 is lower than a certain threshold, the heat dissipation capacity of the energy storage system needs to be weakened to reduce the system power consumption. The flow rate of the second cooling medium can be reduced by reducing the opening of the valve 210, or the power of the water pump 220 can be reduced to reduce the circulation speed of the second cooling medium, or the operating power of the radiator 240 can be reduced to reduce the heat dissipation efficiency of the second cooling medium.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (14)

An energy storage device, characterized in that the energy storage device comprises a liquid collecting tank (110), a battery capsule (120), a battery (130) and a spray device (140), wherein: The liquid collecting box (110) is used to accommodate the battery capsule (120); The battery capsule (120) is used to accommodate the battery (130), and the battery capsule (120) is filled with a first cooling medium, and the first cooling medium is used to cool the battery (130); The spray device (140) is located above the top surface of the battery capsule (120), and the spray device (140) is used to spray a second cooling medium onto the outer surface of the top surface of the battery capsule (120). The energy storage device according to claim 1, characterized in that at least one liquid inlet (150) and at least one liquid outlet (160) are provided on a side of the liquid collecting tank (110), The liquid inlet (150) is in communication with the spray device, and the second cooling medium flows into the spray device (140) through the liquid inlet (150); The second cooling medium flows out of the liquid collecting tank (110) through the liquid outlet (160). The energy storage device according to claim 2, characterized in that the liquid outlet (160) is higher than the bottom surface of the battery capsule (120) and lower than the top surface of the battery capsule (120), or the liquid outlet (160) is higher than the top surface of the battery capsule (120). The energy storage device according to any one of claims 1 to 3, characterized in that the inner surface of the battery capsule (120) is provided with heat dissipation fins (121). The energy storage device according to any one of claims 1 to 4, characterized in that the top surface of the battery capsule (120) is an arc surface, and the side surface of the battery capsule (120) is perpendicular to the bottom surface of the battery capsule (120); or, The top surface and side surfaces of the battery capsule (120) are both arc surfaces; or, The battery capsule (120) is a cubic structure; or, The battery capsule (120) is a rectangular parallelepiped structure. The energy storage device according to any one of claims 1 to 5, characterized in that the battery (130) is partially or completely immersed in the first cooling medium. The energy storage device according to any one of claims 1 to 6, characterized in that the battery capsule (120) is a fully sealed structure. The energy storage device according to any one of claims 1 to 7 is characterized in that the first cooling medium is an oil cooling medium and/or a fluorinated liquid cooling medium, and the second cooling medium includes any one of the following: ethylene glycol aqueous solution, nanofluid, phase change emulsion. The energy storage device according to any one of claims 1 to 8, characterized in that the battery (130) is a square battery or a cylindrical battery or a soft-pack battery. The energy storage device according to any one of claims 1 to 9, characterized in that the spray device (140) is fixed to the outer side of the top surface of the battery capsule (120), or the spray device (140) is fixed to the inner side of the top surface of the liquid collecting tank (110). An energy storage system, characterized by comprising: The energy storage device according to any one of claims 1 to 10; A heat dissipation circuit is used to cool the second cooling medium. The energy storage system according to claim 11, characterized in that the heat dissipation circuit comprises a valve (210), a water pump (220), a radiator (240) and a piping system, wherein the valve (210) is used to control the flow rate of the second cooling medium in the energy storage system, the water pump (220) is used to provide circulation power for the second cooling medium in the energy storage system, the radiator (240) is used to dissipate heat for the second cooling medium, and the piping system is used to connect the valve (210), the water pump (220) and the radiator (240). The energy storage system according to claim 12 is characterized in that, in response to the temperature of the battery (130) being higher than a preset temperature value, the opening of the valve (210) increases or the operating power of the water pump (220) increases or the operating power of the radiator (240) increases. The energy storage system according to claim 12 or 13 is characterized in that, in response to the temperature of the battery (130) being lower than the preset temperature value, the opening of the valve (210) is reduced or the operating power of the water pump (220) is reduced or the operating power of the radiator (240) is reduced.