JP5556629B2 - Sealed battery - Google Patents

Description

  The present invention relates to a sealed battery (hereinafter also simply referred to as a battery) provided with a safety mechanism that performs a predetermined safety ensuring operation.

In recent years, a chargeable / dischargeable battery has been used as a driving power source for vehicles such as hybrid vehicles and electric vehicles, and portable electronic devices such as notebook computers and video camcorders.
As such a battery, for example, Patent Document 1 includes a non-aqueous electrolyte battery (sealed battery) that includes a current interruption mechanism (safety mechanism) and includes lithium carbonate (gas generating agent) in the positive electrode mixture of the positive electrode plate. Is disclosed. In this battery, when overcharged, lithium carbonate in the positive electrode mixture is decomposed and gas is generated, and the internal pressure of the battery case is increased, so that the current interruption mechanism can be operated.

JP 2008-159536 A

  However, the battery described in Patent Document 1 is overcharged, and even when gas is generated from the positive electrode mixture, a part of the generated gas continues to be retained in the electrode body and does not escape from the electrode body. Case) The internal pressure may not be sufficiently increased. For this reason, the operation of the current cutoff valve (safety mechanism) may be difficult or delayed in spite of the fact that gas has already been generated due to overvoltage.

  This invention is made | formed in view of this problem, Comprising: It aims at providing the sealed battery which can operate a safety mechanism reliably, when it becomes an overcharge.

One aspect of the present invention includes an electrode body including a positive electrode plate and a negative electrode plate, a battery case containing the electrode body, and a battery case that operates when an internal pressure of the battery case exceeds a predetermined operating pressure. A positive electrode that is disposed outside the electrode body and is electrically connected to the positive electrode plate so that its own potential becomes the positive electrode potential of the positive electrode plate. A potential generating member and a gas generating agent that generates a gas when its own potential is equal to or greater than a predetermined gas generation potential, and is disposed in contact with the positive electrode potential member in the battery case. An overcharge gas generating agent in the range of the overcharge positive electrode potential that is the positive electrode potential when the sealed battery is overcharged, and an electrolyte solution, the electrolyte solution comprising: Includes the overcharge gas generating agent, and the electrode body In the battery case, and the positive electrode potential member is in a position to normally take the sealed battery, and the stored electrolytic solution is stored in the battery case outside the electrode body. It is a sealed battery formed in contact with a liquid .

The above-described battery includes a positive electrode potential member and an overcharge gas generating agent disposed outside the electrode body. Moreover, the overcharge gas generating agent is disposed in contact with the positive electrode potential member in the battery case. For this reason, when the battery is overcharged and the potential of the positive electrode plate and the positive electrode potential member conducted to the positive electrode plate is equal to or higher than the overcharge positive electrode potential, the overcharge gas generating agent in contact with the positive electrode potential member generates gas. . Since this gas is not held in the electrode body, the internal pressure in the battery case can be immediately increased. Therefore, the above-described battery can reliably operate the safety mechanism when overcharged.
Moreover, when the above-described battery is overcharged, the overcharge gas generating agent in the stored electrolyte that contacts the positive electrode potential member generates gas. In addition, the overcharge gas generating agent in the retained electrolyte in contact with the positive electrode plate in the electrode body can also generate gas. Therefore, in the case of overcharging, a battery that can reliably operate the safety mechanism can be obtained.

The positive electrode potential member is a member that conducts with the positive electrode plate to become a positive electrode potential, and examples thereof include a positive electrode current collecting terminal member connected to the positive electrode plate. Further, as the positive electrode potential member, in order to make contact with the overcharge gas generating agent in the battery case, a member provided separately from the positive electrode current collector terminal member or extended from the positive electrode current collector terminal member Part can also be used. Further, when the battery case itself is conducted to the positive electrode plate, the battery case can be used as a positive electrode potential member. That is, the battery case can also serve as the battery case and the positive electrode potential member.
Examples of the shape of the positive electrode potential member include a plate shape, a rod shape, a mesh shape, and a porous shape. In particular, when the positive electrode potential member has a plate-like or rod-like shape, a surface area increasing process for increasing the surface area of the contacted part is performed on the contacted part of the positive electrode potential member that is contacted by the overcharge gas generating agent. Good to be.

Further, as the arrangement form of the overcharge gas generating agent, for example, a positive electrode potential member such as applying a paste containing an overcharge gas generating agent to the positive electrode potential member or depositing the overcharge gas generating agent on the positive electrode potential member. The form which forms an overcharge gas generating agent in the form of a film | membrane on the surface of this is mentioned. Moreover, while mixing an overcharge gas generating agent with electrolyte solution, it is set as the form which an overcharge gas generator contacts a positive electrode potential member by setting it as the form which contacts a positive electrode potential member with the stored electrolyte stored in the battery case. Also good.
Moreover, as an overcharge gas generating agent arrange | positioned in the form of a film | membrane on the surface of a positive electrode potential member, lithium carbonate (oxidative decomposition potential 4.5V vs. Li < ⁺ > / Li) is mentioned, for example. Examples of the overcharge gas generating agent that can be mixed in the electrolyte include cyclohexylbenzene (oxidative decomposition potential 4.7 V vs. Li ⁺ / Li), transbutyl cyclohexylbenzene (4.7 V vs. Li ⁺ / Li), 4-fluorophenyl-acetate (4.8V vs.Li ⁺ / Li), Bicester tertiary butyl phenyl carbonate (4.8V vs.Li ⁺ / Li), tris-4-tert-butylphenyl phosphate (4.9 V vs. Li ⁺ / Li), methyl phenyl carbonate (4.9 V vs. Li ⁺ / Li), diphenyl carbonate (5.0 V vs. Li ⁺ / Li), phenyl fluoride (5.0 V vs. Li ⁺ / Li) Can be mentioned. In addition, when mixing the overcharge gas generating agent with the electrolytic solution, in consideration of the posture normally taken by the battery, as much as possible of the surface of the positive electrode potential member normally contacts the stored electrolytic solution. It is good to arrange a member. This is because, even in the positive electrode potential member, gas is generated at the time of overcharge from a portion where the electrolyte containing the overcharge gas generating agent is in contact.
Moreover, the arrangement | positioning form mentioned above can also be used together. For example, the portion of the positive electrode potential member that contacts the stored electrolyte when in a normal posture is exposed to the electrolyte solution containing the overcharge gas generating agent by exposing the surface of the positive electrode potential member. An overcharge gas generating agent is formed in a film shape on the surface of the site. In this way, two types of overcharge gas generating agents can be disposed in contact with the positive electrode potential member.

In addition, as a safety mechanism, for example, when the internal pressure of the battery case becomes equal to or higher than the operating pressure due to overcharging or the like, a current interruption mechanism that performs a safety ensuring operation that interrupts the current flowing through the electrode body, along with the interruption of the current, An internal pressure reduction mechanism for interrupting current and performing a safety ensuring operation for releasing gas to the outside of the battery to reduce the internal pressure can be mentioned.
Further, at the time of overcharging, gas generation by contact between the positive electrode plate and the overcharge gas generating agent in the electrode body may be performed in parallel with gas generation by contact between the positive electrode potential member and the overcharge gas generating agent. good. For example, an overcharge gas generating agent may be included in the positive electrode active material layer (positive electrode mixture layer) of the positive electrode plate. In addition, when an overcharge gas generating agent is mixed with the electrolytic solution, the retained electrolytic solution held in the electrode body in parallel with gas generation due to contact between the stored electrolytic solution stored outside the electrode body and the positive electrode potential member Gas generation also occurs due to contact between the electrode and the positive electrode plate.

  Further, in the above-described sealed battery, the contacted portion that is in contact with the overcharge gas generating agent of the positive electrode potential member is sealed by a surface area increasing process for increasing the surface area of the contacted portion. Type battery.

  In the above-described battery, the surface area increasing process is performed on the contacted portion with which the overcharge gas generating agent contacts among the positive electrode potential members. For this reason, compared with the battery using the positive electrode potential member which has the to-be-contacted part which is not processed like this, the quantity of the overcharge gas generating agent exposed to a positive electrode potential can be increased. Therefore, when the battery is overcharged, more gas can be efficiently generated from the overcharge gas generating agent that contacts the positive electrode potential member.

  Examples of the surface area increasing process applied to the contacted part of the positive electrode potential member include, for example, a process of providing an uneven shape such as a comb tooth shape or a slit in the contacted part of the positive electrode member, sandblasting, roughening etching, acicular plating, etc. The surface roughening treatment can increase the surface area by increasing the surface roughness of the contacted part.

  Furthermore, in any of the above-described sealed batteries, the battery case is preferably a sealed battery made of metal and also serving as the positive electrode potential member.

  In the battery described above, the battery case is made of metal and also serves as a positive electrode potential member. Therefore, it is not necessary to separately provide a positive electrode potential member, and a battery having a simple structure can be obtained. Alternatively, in addition to the existing positive electrode potential member, the positive electrode potential member can be easily increased.

  Examples of the method for electrically connecting the battery case to the positive electrode plate include a method for bringing the positive electrode current collecting terminal member taken outside into direct contact with the battery case, and a method for electrically connecting both of them through a conductive material.

It is a perspective view of the battery concerning an embodiment. It is a partial fracture top view of the battery concerning an embodiment. It is a partial expanded sectional view (A section of Drawing 2) of the battery concerning an embodiment. It is explanatory drawing of the electric current interruption apparatus of embodiment. It is a partial expanded sectional view (B section of Drawing 2) of the battery concerning an embodiment. It is a graph which shows the time-dependent change of the temperature of a battery, a positive electrode electric potential, and the internal pressure of a battery case in an overcharge test. It is explanatory drawing of the manufacturing method of the battery concerning embodiment. It is explanatory drawing of the manufacturing method of the battery concerning embodiment. It is explanatory drawing of the manufacturing method of the battery concerning embodiment. It is explanatory drawing which illustrates the reference form of a battery. It is explanatory drawing which illustrates further another form of a battery. It is explanatory drawing which illustrates the reference form of a battery. It is explanatory drawing which illustrates further another form of a battery. It is explanatory drawing which illustrates further another form of a battery.

(Embodiment)
Next, embodiments of the present invention will be described with reference to the drawings.
First, the battery 1 according to the present embodiment will be described. The battery 1 includes an electrode body 20 including a positive electrode plate 21 and a negative electrode plate 22, a gas generating agent GS made of cyclohexylbenzene, an electrolytic solution 30 containing the gas generating agent GS, and the electrode body 20 and the electrolytic solution 30. It is a sealed lithium ion secondary battery having a battery case 10 containing (gas generating agent GS) (see FIGS. 1 and 2). In addition, the battery 1 includes a negative electrode terminal structure 70, a positive electrode terminal structure 60, and a current interrupt device SD that blocks the current flowing through the electrode body 20 (safety ensuring operation) in the positive electrode terminal structure 60. (See FIGS. 1 and 2).

  Among these, the battery case 10 includes a case main body member 11 including an opening and a sealing lid 12. Among these, the sealing lid 12 has a rectangular plate shape, closes the opening of the case body member 11, and is welded to the case body member 11.

  The electrode body 20 is formed by winding a belt-like positive electrode plate 21 and a negative electrode plate 22 into a flat shape via a belt-like separator (not shown) made of polyethylene (see FIG. 1). The positive electrode plate 21 and the negative electrode plate 22 of the electrode body 20 are respectively joined to a positive electrode internal terminal structure 63 (positive electrode current collecting member 64) or a negative electrode internal terminal member 73 described later (see FIG. 2).

  The positive electrode plate 21 of the electrode body 20 is formed by carrying a positive electrode active material layer (not shown) on both surfaces of the strip-shaped aluminum foil, leaving a positive electrode lead portion 21f along one side. Moreover, the negative electrode plate 22 carries the negative electrode active material layer which is not shown in figure on both surfaces, leaving the negative electrode lead part 22f along one side among strip | belt-shaped copper foil.

The electrolytic solution 30 was prepared by adding LiPF ₆ as a solute to a mixed organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were adjusted to a volume ratio of EC: EMC = 3: 7, and lithium ions 1 Organic electrolyte having a concentration of 0.0 mol / l. Further, 2 wt% of cyclohexylbenzene (gas generating agent) GS is added to the electrolytic solution 30.
In the present embodiment, the electrolytic solution 30 is classified according to the difference in the parts to be held. That is, the electrolytic solution impregnated in the electrode body 20 and retained in the electrode body 20 is referred to as a retained electrolytic solution 30H. In addition, as a result of injecting more electrolytic solution into the battery case 10 than impregnating and holding the electrode body 20, as shown in FIG. 2, the electrolytic solution stored in the battery case 10 outside the electrode body 20 is stored. This is referred to as an electrolytic solution 30S.
In the battery 1 of the present embodiment, in the battery 1, the ratio of the amount of the retained electrolyte 30H and the stored electrolyte 30S is retained electrolyte 30H: stored electrolyte 30S = 90: 10.

Cyclohexylbenzene (gas generant) GS has an oxidative decomposition potential of 4.7 V vs. Li ⁺ / Li. Therefore, the potential of the gas generating agent GS itself is 4.7 V vs. When it becomes more than Li ⁺ / Li, an oxidative decomposition reaction occurs to generate gas from itself.
The oxidative decomposition potential of the gas generating agent GS is the positive electrode potential (4.15 V vs. Li ⁺ / Li) when the battery 1 according to the present embodiment is fully charged (SOC is 100% in the charged state (SOC)). Higher). That is, the potential at which gas is generated from the gas generating agent GS (oxidative decomposition potential: 4.7 V vs. Li ⁺ / Li in the present embodiment) exceeds 100% of the SOC 1 and is in an overcharged state. It is in the range of the overcharged positive electrode potential (in this embodiment, more than 4.15 V vs. Li ⁺ / Li) which is the positive electrode potential of the positive electrode plate 21.

The negative electrode terminal structure 70 includes a negative electrode external terminal member 71 made of aluminum, a negative electrode internal terminal member 73 which is also made of aluminum, and is mainly located inside the battery case 10, and a gasket 72 made of an insulating resin ( (See FIG. 2).
Among these, the negative electrode internal terminal member 73 is joined to the negative electrode lead portion 22f of the negative electrode plate 22 in the battery case 10, and on the other hand, penetrates the sealing lid 12 of the battery case 10, and the negative electrode external terminal member 71 and The gasket 72 is caulked to the sealing lid 12 and is electrically connected to the negative external terminal member 71.
Further, the negative external terminal member 71 bent in a crank shape has a through hole 71H for fastening a bus bar or the like with a bolt on the tip side. A gasket 72 is interposed between the negative electrode external terminal member 71 and the negative electrode internal terminal member 73 and the battery case 10 to insulate them.

On the other hand, the positive electrode terminal structure 60 includes a positive electrode external terminal member 61 made of copper, a positive electrode internal terminal structure 63 positioned mainly inside the battery case 10, and a gasket 62 made of an insulating resin.
Among these, the positive electrode external terminal member 61 bent in a crank shape has a through hole 61H for fastening a bus bar or the like with a bolt on the tip side. A gasket 62 is interposed between the positive electrode external terminal member 61 and the positive electrode internal terminal structure 63 and the battery case 10 to insulate them.

2 and 3, the positive electrode internal terminal structure 63 includes a rectangular concave relay member 66, a caulking member 65, a positive electrode current collecting member 64, and a substantially flat diaphragm as shown in FIGS. 67. Among these, the caulking member 65 penetrates the through hole 12H of the sealing lid 12 and caulks the relay member 66, the positive external terminal member 61, and the gasket 62 to the sealing lid 12. In addition, the relay member 66 and the positive external terminal member 61 are electrically connected. Further, the positive electrode current collecting member 64 is joined to the positive electrode lead portion 21 f of the positive electrode plate 21. Further, the diaphragm 67 is interposed between the positive electrode current collecting member 64 and the relay member 66 to turn on / off the conduction between the two.
The positive electrode internal terminal structure 63 is made of polypropylene and includes an enclosing member 68 that encloses the flat plate-like main body portion 64 </ b> X of the positive electrode current collecting member 64.

  In the positive electrode internal terminal structure 63, the relay member 66 is airtightly joined to the peripheral portion 67E of the diaphragm 67 at the peripheral portion 66E. Thereby, the relay member 66, the caulking member 65, and the diaphragm 67 form a space C. In the present embodiment, since the space C communicates with the outside of the battery case 10 through the through-hole 65H of the caulking member 65, the air pressure in the space C is atmospheric pressure (see FIG. 3). ).

On the other hand, the positive electrode current collecting member 64 has a rectangular plate-shaped main body portion 64X as shown in FIG. 7A, and extends downward from the main body portion 64X in the shape of a crank in FIG. 7A. It consists of a strip-shaped current collector 64Y. Among these, the main body portion 64X is formed with two through holes 64H and 64H that pass through the main body portion 64X itself. Further, as shown in FIG. 7B, in a state where the main body portion 64X is surrounded by the surrounding member 68, an exposed portion 64A which is a part of the main body portion 64X is interposed between the two through holes 64H and 64H. It is exposed from the surrounding member 68. Further, the positive electrode current collecting member 64 is joined to the positive electrode lead portion 21f of the positive electrode plate 21 in the current collecting portion 64Y.
Moreover, the surrounding member 68 has the through-hole 68H which coat | covers the through-hole 64H of the positive electrode current collection member 64 (refer FIG. 3). For this reason, the internal pressure of the battery case 10 is applied to the diaphragm 67 through the through hole 68H.

  The diaphragm 67 protrudes toward the main body portion 64X described above, and bends in a U-shape with a contact portion 67A that contacts the exposed portion 64A of the positive electrode current collecting member 64 when the internal pressure of the battery case 10 shown in FIG. 3 is low. And a bent portion 67D that annularly surrounds the contact portion 67A outside the through hole 68H of the surrounding member 68 (see FIGS. 3, 4, and 8).

  The positive electrode current collecting member 64, the diaphragm 67, and the surrounding member 68 form a current interrupt device SD that interrupts the current flowing through the electrode body 20 (safety ensuring operation) when the internal pressure of the battery case 10 increases. . Specifically, for example, when the internal pressure of the battery case 10 increases due to overcharging of the battery 1 and becomes equal to or higher than the operating pressure (450 kPa in the present embodiment), as shown in FIG. The internal pressure F of the battery 1 is applied to the lower surface of the diaphragm 67 in the drawing through the through hole 68H and the through hole 64H of the main body portion 64X. When the internal pressure F exceeds the operating pressure (F> 450 kPa), the diaphragm 67 is lifted upward in FIG. As a result, the contact portion 67A of the diaphragm 67 is separated from the exposed portion 64A of the positive current collecting member 64, so that the positive electrode external terminal member 61-caulking member 65-relay member 66-diaphragm 67-positive current collecting member 64 are routed. The current flowing through the electrode body 20 is interrupted, and charging (overcharge) of the battery 1 is stopped.

  In addition, as shown in FIG. 2, the positive electrode current collecting member 64 of the positive electrode internal terminal structure 63 and the battery case 10 disposed outside the electrode body 20 are connected via a conductor CL. For this reason, the battery case 10 is electrically connected to the positive electrode plate 21 of the electrode body 20 through the conductor CL. Therefore, in the battery 1 of this embodiment, the potential of the battery case 10 is equal to the positive electrode potential of the positive electrode plate 21.

Further, as shown in FIG. 2 and FIG. 5 which is an enlarged cross-sectional view of a portion B of FIG. 2, the battery case 10 has a cyclohexylbenzene (gas generating agent) GS in the stored electrolyte 30S on its inner peripheral surface. The contact part 16 which contacts is attached. When the contact portion 16 is in a posture in which the battery 1 is normally taken (specifically, in the battery 1 in FIGS. 2 and 5, a posture in which gravity works downward from the top in the figure), the stored electrolyte 30 </ b> S ( It is a part which contacts gas generating agent GS). For this reason, when the positive electrode potential of the positive electrode plate 21 (potential of the battery case 10) becomes equal to or higher than the oxidative decomposition potential (4.7 V vs. Li ⁺ / Li) of the gas generating agent GS during overcharging, the contact portion A gas is generated from the gas generating agent GS that contacts 16.
Moreover, the contact portion 16 is subjected to a surface area increasing process for increasing the surface area in contact with the stored electrolyte 30S. Specifically, by using surface roughening with sandpaper, the 10-point average roughness Rz (JIS Standard B0601 Annex 1) of the contact portion 16 is 6.0 μm, which is rougher than normal (2.0 μm). It is. For this reason, in the battery 1 of the present embodiment, the surface area where the stored electrolyte 30S is in contact with the contact portion 16 can be increased as compared with a battery using a battery case having a contact portion that has not been processed in this way. The amount of the gas generating agent GS exposed to the positive electrode potential can be increased.

By the way, the present inventors prepared the battery 1 described above and the comparative battery C1 of the battery 1, and performed an overcharge test on each battery. And about each battery, time after starting an overcharge test until the electric current interruption apparatus SD act | operated was measured and compared.
In addition, the comparative battery C1 does not have the conducting wire CL that connects the positive electrode current collecting member 64 and the battery case 10, and the battery 1 is not electrically connected (insulated) to the positive electrode plate. And different.
Specifically, constant current charging was performed at a constant current value (2C) for each of the batteries 1 and C1 in which the state of charge (SOC) was SOC 0%.

The relationship between the time from the start of the overcharge test of each battery 1 and C1, the temperature of each battery, the positive electrode potential, and the internal pressure of the battery case is shown in the graph of FIG.
In each of the batteries 1 and C1, the positive electrode potential is 4.7 V vs. about 900 seconds. Li ⁺ / Li, and the internal pressure of each battery 1 and C1 starts to increase from the initial 100 kPa. Therefore, the positive electrode potential is 4.7 V vs. Since Li ⁺ / Li, the gas generating agent GS in the electrolytic solution 30 is decomposed in each of the batteries 1 and C1, and it can be seen that gas is generated therefrom.

However, the time required for the internal pressure of each of the batteries 1 and C1 to reach the operating pressure (450 kPa) of the current interrupt device SD is different. Specifically, the time required for the internal pressure of the comparative battery C1 to reach the operating pressure of the current interrupt device SD was about 1700 seconds after the start of the test. On the other hand, the time required for the internal pressure of the battery 1 to reach the operating pressure of the current interrupt device SD is about 1100 seconds later than the comparative battery C1.
In the comparative battery C1, the gas generating agent GS contained in the retained electrolyte 30H in the electrode body 20 is decomposed in the electrolyte 30 and gas is generated. On the other hand, in the battery 1, in addition to the decomposition of the gas generating agent GS in the retained electrolyte 30H, the decomposition also proceeds in the gas generating agent GS in the stored electrolyte 30S, so that much gas is generated accordingly.
Even when gas is generated from the gas generating agent GS of the retained electrolyte 30H, since the positive electrode plate 21 and the negative electrode plate 22 are in close contact with the separator in the electrode body 20, a part of the generated gas is in the electrode body 20. It is difficult to slip out of the electrode body 20 while being held in place. The gas kept in the electrode body 20 hinders the contact between the gas generating agent GS of the retained electrolyte 30H and the positive electrode plate 21, so that even if the positive electrode potential of the positive electrode plate 21 exceeds the oxidative decomposition potential, the gas is retained. A case where the decomposition of the gas generating agent GS of the electrolytic solution 30H is difficult to proceed can be considered.
Therefore, it can be seen that the battery 1 whose decomposition progresses even with the gas generating agent GS in the stored electrolyte 30S has a faster internal pressure rise than the comparative battery C1, and reaches the operating pressure of the current interrupter SD earlier.
In addition, the battery temperature of the comparative battery C1 when the operating pressure of the current interrupting device SD was reached was about 100 ° C., whereas the battery temperature of the battery 1 was about 60 ° C. From this, it is possible to suppress an increase in battery temperature early by operating the current interrupt device SD early.

As described above, the battery 1 of the present embodiment includes the battery case 10 and the gas generating agent GS disposed outside the electrode body 20. Moreover, the gas generating agent GS is disposed in contact with the contact portion 16 of the battery case 10. For this reason, when the battery 1 is overcharged and the potential of the positive electrode plate 21 and the battery case 10 conducted to the positive electrode plate 21 becomes equal to or higher than the overcharged positive electrode potential (4.7 V vs. Li ⁺ / Li), the battery 1 The gas generating agent GS in contact with the case 10 generates gas. Since this gas is generated from the gas generating agent GS in the stored electrolyte 30S in contact with the battery case 10, it is not held in the electrode body 20, and the internal pressure in the battery case 10 can be immediately increased. Therefore, the battery 1 can reliably operate the current interrupting device SD when overcharged.

  Moreover, the surface area increase process is given about the contact part 16 which the gas generating agent GS contacts among the battery cases 10. FIG. For this reason, compared with the battery using the battery case which has the contact part 16 which is not processed like this, the quantity of gas generating agent GS exposed to a positive electrode electric potential can be increased. Therefore, when the battery 1 is overcharged, more gas can be efficiently generated from the gas generating agent GS that contacts the battery case 10.

  Further, since the battery case 10 is made of metal and also serves as a positive electrode potential member, it is not necessary to separately provide a positive electrode potential member, and the battery 1 having a simple structure can be obtained.

  Further, when the battery 1 is overcharged, gas is generated from the gas generating agent GS that is opposed to the stored electrolyte 30 </ b> S that contacts the battery case 10. In addition, gas can also be generated from the gas generating agent GS in the retained electrolyte 30 </ b> H that contacts the positive electrode plate 21 in the electrode body 20. Therefore, in the case of overcharging, the battery 1 can reliably operate the current interrupt device SD.

Next, a method for manufacturing the battery 1 according to the embodiment will be described with reference to the drawings.
First, a positive electrode paste containing positive electrode active material particles (not shown) made of lithium cobaltate was applied to both surfaces of an aluminum foil, and then dried and pressed to form a positive electrode plate 21. On the other hand, a negative electrode paste containing negative electrode active material particles (not shown) made of natural graphite was applied to both surfaces of the copper foil, and then dried and pressed to form a negative electrode plate 22.
The electrode body 20 is formed by winding a separator (not shown) between the positive electrode plate 21 and the negative electrode plate 22 thus manufactured.

  On the other hand, the main body portion 64X of the positive electrode current collector member 64 shown in FIG. 7A is covered with an enclosing member 68 made of an insulating resin member. Specifically, the main body portion 64X of the positive electrode current collecting member 64 is sandwiched between two plate-like insulating resin members 68A and 68B, and these are bonded and fixed. Note that the two plate-like insulating resin members 68A and 68B have through-holes at positions that overlap the through-holes 64H of the main body portion 64X and intermediate positions thereof. Therefore, the completed surrounding member 68 has two through holes 68H and 68H, and the exposed portion 64A of the positive electrode current collecting member 64 is exposed from the surrounding member 68 (see FIG. 7B).

Further, as shown in FIG. 8, the metal member 66, the positive electrode external terminal member 61, and the gasket 62 are caulked to the sealing lid 12 in the sealing lid 12 in which the gasket 62 is disposed. Specifically, a copper rivet 65B whose one end is not expanded in the radial direction was inserted through the metal member 66, the gasket 62 (sealing lid 12), and the positive electrode external terminal member 61 in this order. Then, using a known method, the tip of the rivet 65B was expanded in the radial direction, and the metal member 66, the positive external terminal member 61, and the gasket 62 were caulked to the sealing lid 12.
Thereafter, the peripheral edge portion 66E of the metal member 66 and the peripheral edge portion 67E of the diaphragm 67 were overlapped and welded.

Next, the current collecting portion 64 </ b> Y of the positive electrode current collecting member 64 described above was welded to the positive electrode lead portion 21 f of the positive electrode plate 21 of the electrode body 20. On the other hand, the negative electrode internal terminal member 73 was welded to the negative electrode lead portion 22 f of the negative electrode plate 22.
The electrode body 20 thus formed is connected to the sealing lid 12. Specifically, on the positive electrode side, the exposed portion 64 </ b> A of the positive electrode current collecting member 64 is connected so as to contact the contact portion 67 </ b> A of the diaphragm 67. Then, the peripheral edge 67E of the diaphragm 67 was adhered and fixed to the surrounding member 68. On the other hand, on the negative electrode side, a cylindrical rivet portion 73B whose tip is not expanded in the radial direction among the negative electrode internal terminal member 73 is inserted through the gasket 72 (sealing lid 12) and the negative electrode external terminal member 71 in this order. The tip of the rivet portion 73B was expanded in the radial direction. Thereby, the negative electrode internal terminal member 73 and the negative electrode external terminal member 71 are made conductive while the negative electrode external terminal member 71 and the gasket 72 are caulked to the sealing lid 12.
In addition, the positive electrode current collecting member 64 and the case main body member 11 are electrically connected through a conductive wire CL made of a metal wire. Specifically, one end of the conducting wire CL is previously welded to the positive electrode current collecting member 64 and the other end is welded to the inner peripheral surface of the case main body member 11.

Next, the electrode body 20 is accommodated in the case body member 11, and the case body member 11 is sealed with the sealing lid 12. The contact portion 16 of the case main body member 11 is subjected to a surface area increasing process in advance. Specifically, the contact portion 16 is subjected to surface roughening using sandpaper, and the ten-point average roughness Rz is set to 6.0 μm.
Thereafter, the electrolytic solution 30 is injected from the injection hole 12J of the sealing lid 12, and the injection hole 12J is sealed to complete the battery 1 (see FIG. 1).

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, the current interrupting device that performs a safety ensuring operation that interrupts the current flowing through the electrode body 20 when the internal pressure of the battery case 10 (battery 1) becomes equal to or higher than the operating pressure due to overcharging or the like. SD was shown. However, the current interruption is not limited to this, and the current interruption that performs two safety ensuring operations, such as the operation of interrupting the current of the electrode body and the operation of reducing the internal pressure of the battery case by releasing gas to the outside of the battery case. A combined internal pressure lowering mechanism may be used.

Further, in the embodiment, as an arrangement form of the overcharge gas generating agent, an arrangement form in which the gas generating agent GS (cyclohexyl benzene) is mixed with the electrolytic solution 30 and the battery case 10 as the positive electrode potential member is brought into contact with the stored electrolytic solution 30S. showed that. However, for example, the paste containing the overcharge gas generating agent is applied to the positive electrode potential member, and the overcharge gas generating agent is deposited on the positive electrode potential member. It is good also as a form formed and arranged in the form of a film. Moreover, for example, in a positive electrode potential member having an opening-like cage-shaped housing portion, an embodiment in which an overcharge gas generating agent is disposed in the housing portion can be mentioned.
Further, cyclohexylbenzene was used as an overcharge gas generating agent to be mixed with the electrolytic solution. For example, transbutylcyclohexylbenzene, 4-fluorophenylacetate, bisterly butylphenyl carbonate, tris-4-tertiarybutylphenyl phosphate, methyl Phenyl carbonate, diphenyl carbonate, and phenyl fluoride may be used. Moreover, as an overcharge gas generating agent used when arrange | positioning in the shape of a film | membrane on the surface of a positive electrode potential member among overcharge gas generating agents, lithium carbonate is mentioned, for example. In addition, among the overcharge gas generating agents, in the positive electrode potential member having the accommodating portion, as the overcharge gas generating agent used when being arranged in the accommodating portion, for example, lithium carbonate can be cited.

  Further, in the embodiment, the battery case 10 is configured to serve as the battery case and the positive electrode potential member. However, the positive electrode potential member may be, for example, the positive electrode current collecting member 164 joined to the positive electrode plate 21 (positive electrode lead portion 21f) (see FIG. 10). As an arrangement form of the overcharge gas generating agent in such a case, for example, an overcharge gas generating agent is formed in a film shape on the surface of the positive electrode current collector 164 (positive electrode potential member) and arranged. Is mentioned. Specifically, in the battery 101, a paste obtained by kneading the above-described overcharge gas generating agent GS1 made of lithium carbonate together with a binder and a solvent is applied to the surface of the positive electrode current collector 164, and then dried. A coating film WP is formed and disposed on the surface of the current collecting member 164. When the battery 101 is overcharged and the potential of the positive electrode plate 21 and the positive electrode current collector 164 conducted to the positive electrode plate 21 is equal to or higher than the overcharge positive electrode potential, the overcharge in the coating WP in contact with the positive electrode current collector 164 is exceeded. The charging gas generating agent GS1 generates gas.

  Further, for example, a member provided separately from the positive electrode current collector described above may be used. Specifically, as shown in FIG. 11, a battery 201 including a flat plate-like positive electrode potential member 240 made of a metal and immersed in a stored electrolyte 30 </ b> S is exemplified. In the battery 201, the positive electrode current collecting member 264 and the positive electrode potential member 240 are electrically connected through the conducting wire CL. Therefore, when the battery 201 is overcharged and the potential of the positive electrode potential member 240 conducted to the positive electrode plate 21 becomes equal to or higher than the overcharge positive electrode potential, the gas generating agent GS in the stored electrolyte 30S in contact with the positive electrode potential member 240 is gas. Is generated.

  Further, for example, a portion extended from the positive electrode current collector described above may be used for the positive electrode potential member. Specifically, as shown in FIG. 12, a battery 301 having an extended portion A <b> 10 that extends from the positive electrode current collector 364 can be given. On the surface of the extending portion A10 of the battery 301, a coating film WP containing an overcharge gas generating agent GS1 made of lithium carbonate is disposed. For this reason, when the battery 301 is overcharged and the potential of the extension portion A10 becomes equal to or higher than the overcharge positive electrode potential, the overcharge gas generating agent GS1 in the coating WP in contact with the extension portion A10 generates gas.

  Moreover, for example, as shown in FIG. 13, a battery 401 having a configuration in which an extending portion A <b> 20 extending from the positive electrode current collecting member 464 is immersed in the stored electrolyte 30 </ b> S is also included. When the battery 401 is overcharged, the gas generating agent GS in contact with the contact portion A21 of the extending portion A20 generates gas.

Further, for example, two types of overcharge gas generating agents (a gas generating agent GS made of cyclohexylbenzene and an overcharge gas generating agent GS1 made of lithium carbonate) may be disposed in contact with the positive electrode potential member. Specifically, a battery 501 including an extension part A30 (a positive electrode potential member) extended from the positive electrode current collector 564 can be given (see FIG. 14). The extending portion A30 includes a contact portion A31 immersed in the stored electrolyte 30S, and an intermediate portion A32 located between the contact portion A31 and the positive electrode current collector 564.
Among these, the intermediate part A32 is placed in the stored electrolyte 30S when the battery 501 is in a normal posture (specifically, in the battery 501 in FIG. 14, a posture in which gravity works downward from the top in the drawing). Does not touch. A coating film WP containing an overcharge gas generating agent GS1 made of lithium carbonate is disposed on the surface of the intermediate portion A32. For this reason, when the battery 501 is overcharged and the potential of the extension part A30 becomes equal to or higher than the overcharged positive electrode potential, the coating material disposed in the intermediate part A32 together with the gas generating agent GS in the stored electrolyte 30S that contacts the contact part A31. The overcharge gas generating agent GS1 in the membrane WP generates gas.

  The shape of the positive electrode potential member can be, for example, a plate shape, a rod shape, a mesh shape, or a porous shape. In particular, when the positive electrode potential member has a plate-like or rod-like shape, a surface area increasing process for increasing the surface area of the contacted part is performed on the contacted part of the positive electrode potential member that comes into contact with the overcharge gas generating agent. It is good to leave.

  In the embodiment, the contacted portion (contact surface 16) of the battery case 10 has been subjected to surface area increasing processing with a ten-point average roughness Rz of 6.0 μm by surface roughening using sandpaper. The surface area of the contacted part is increased and the surface area is increased by processing the surface to be contacted such as a comb-like shape or slits, or by surface roughening such as sandblasting, roughening etching, or needle-like plating. Processing may be performed.

1,101,201,301,401,501 Battery (sealed battery)
10 Battery case (positive potential member)
16 Contact part (contacted part)
20 Electrode body 21 Positive electrode plate 22 Negative electrode plate 30 Electrolytic solution 30H Holding electrolytic solution 30S Storage electrolytic solution 164 Positive electrode current collecting member (positive electrode potential member)
240 Positive electrode potential member A10, A20, A30 Distraction part (positive electrode potential member)
A21, A31, A32 Contact part (contacted part)
GS, GS1 Gas generant (overcharge gas generant)
SD Current interrupt device (safety mechanism)

Claims (3)

An electrode body including a positive electrode plate and a negative electrode plate;
A battery case containing the electrode body;
A safety mechanism that operates when the internal pressure of the battery case exceeds a predetermined operating pressure and performs a predetermined safety ensuring operation,
A positive electrode potential member disposed outside the electrode body, electrically connected to the positive electrode plate, and having its own potential at the positive electrode potential of the positive electrode plate;
A gas generating agent that generates gas when its own potential is equal to or greater than a predetermined gas generation potential, and is disposed in contact with the positive electrode potential member in the battery case. An overcharge gas generating agent having an electric potential within a range of an overcharge positive electrode potential that is the positive electrode potential when the sealed battery is overcharged;
An electrolyte solution ,
The electrolyte is
Including the overcharge gas generating agent,
The holding electrolyte solution held in the electrode body, and the stored electrolyte solution stored in the battery case outside the electrode body,
The positive electrode potential member is
A sealed battery, which is configured to come into contact with the stored electrolyte when the sealed battery is in a normal posture . The sealed battery according to claim 1,
Of the positive electrode potential member, a contacted part to which the overcharge gas generating agent contacts is a sealed battery in which a surface area increasing process for increasing the surface area of the contacted part is performed. The sealed battery according to claim 1 or 2,
The battery case is
A sealed battery made of metal and also serving as the positive electrode potential member.

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