Battery cell and battery module

Abstract

To obtain a battery cell and a battery module, capable of suppressing an over charging so as to be stable only in an abnormal state of the battery cell.SOLUTION: A battery cell 20 contains: a laminate outer casing body 22 that is formed by a laminate material containing a metal layer; an electrode body 25 that is constructed so that a positive electrode 25A and a negative electrode 25B are alternately laminated while nipping a separator, and which is houses in an internal part of the laminate outer casing body 22; a pair of tubs 26 and 28 that is connected to each of the positive electrode 25A and a negative electrode 25B, and is extended to an external part of the laminate outer casing body 22; and a pair of conductive members 30 and 32 that is electrically connected to the metal layer, is arranged so as to be separated from the tubs 26 and 28, and is contacted to the pair of tubs 26 and 28 in accordance with an expansion of the laminate outer casing body 22.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a battery cell and a battery module. [Background technology]

[0002] Patent Document 1 discloses a pouch-type secondary battery including an electrode assembly (electrode body) and a pouch exterior body. Specifically, the pouch exterior body of the pouch-type secondary battery described in Patent Document 1 is composed of a first pouch part and a second pouch part, with a first electrode lead attached to the first pouch part and a second electrode lead attached to the second pouch part. In addition, in the pouch-type secondary battery described in Patent Document 1, the first electrode lead and the second electrode lead are electrically connected by a film-type connecting member, and when the pouch exterior body expands due to overcharging or the like, the film-type connecting member breaks and charging is cut off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-64881 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the structure of Patent Document 1, it is difficult to stably break the film-type connecting member when the pouch exterior body expands. Also, even when the pouch exterior body is in a normal state where it is not expanded, the film-type connecting member may break unintentionally due to the input of an external force, etc.

[0005] In consideration of the above, an object of the present invention is to provide a battery cell and a battery module that can stably suppress overcharging only when an abnormality occurs in a battery cell. [Means for solving the problem]

[0006] The battery cell of claim 1 comprises a laminated exterior body formed of a laminate material including a metal layer, an electrode body constructed by alternately stacking positive and negative electrodes with a separator sandwiched therebetween and contained inside the laminated exterior body, a pair of tabs connected to the positive and negative electrodes, respectively, and extending to the outside of the laminated exterior body, and a pair of conductive members electrically connected to the metal layer, positioned at a distance from the tabs, and coming into contact with each of the pair of tabs as the laminated exterior body expands.

[0007] In the battery cell according to claim 1, the laminated exterior body is formed of a laminate material including a metal layer, and an electrode assembly is housed inside the laminated exterior body. Furthermore, tabs are connected to the positive and negative electrodes constituting the electrode assembly, and these tabs extend to the outside of the laminated exterior body. This allows the battery cell to be charged and discharged via the tabs.

[0008] Furthermore, the battery includes a pair of conductive members arranged at a distance from the tabs, and each of these conductive members is electrically connected to a metal layer of the laminate material. Each of the pair of conductive members comes into contact with the tab as the laminate exterior body expands. As a result, when the laminate exterior body expands, the tab on the positive electrode side and the tab on the negative electrode side are short-circuited via the metal layer, thereby preventing overcharging. When the laminate exterior body returns from the expanded state to its original state, the short-circuit state is released.

[0009] The battery cell according to claim 2 is the battery cell according to claim 1, wherein the laminate exterior body has an exposed portion where the metal layer is exposed, and the pair of conductive members are joined to the metal layer at the exposed portion.

[0010] In the battery cell according to claim 2, the exposed metal layer and the conductive member are joined together to provide electrical continuity between them. This eliminates the need for a component for connecting the conductive member and the metal layer, and enables the pair of tabs to be short-circuited with a simple structure.

[0011] The battery cell according to claim 3 is the battery cell according to claim 2, wherein the exposed portion is provided at a position that does not overlap with the tab when viewed from the stacking direction of the electrode body.

[0012] In the battery cell according to claim 3, by arranging the exposed portion in a position that does not overlap with the tab when viewed in the stacking direction of the electrode body, unintentional electrical connection between the tab and the metal layer can be suppressed.

[0013] The battery cell according to claim 4 is the battery cell according to claim 1, wherein the conductive member is provided at a position that does not overlap the electrode body when viewed from the stacking direction of the electrode body.

[0014] In the battery cell according to claim 4, the conductive member is provided in a position that does not overlap with the electrode body when viewed from the stacking direction of the electrode body. This places the conductive member in a position where the cell is likely to expand, making it easier for the tab and the conductive member to come into contact with each other as the cell expands.

[0015] A battery cell according to claim 5 is the battery cell according to claim 1, wherein at least a part of the conductive member is arranged in a position overlapping with the tab when viewed in the stacking direction of the electrode assembly.

[0016] In the battery cell according to claim 5, by arranging at least a part of the conductive member in a position overlapping the tab when viewed in the stacking direction of the electrode assembly, the tab and the conductive member are more likely to come into contact with each other as the cell expands.

[0017] The battery cell according to claim 6 is the battery cell according to claim 1, wherein the tab entirely overlaps the conductive member when viewed in the stacking direction of the electrode assemblies.

[0018] In the battery cell according to claim 6, the entirety of the tab overlaps the conductive member when viewed in the stacking direction of the electrode assembly, so that the tab and the conductive member are more likely to come into contact with each other reliably as the cell expands.

[0019] The battery cell of claim 7 is similar to claim 2, in that the conductive member has a tab side contact portion on one side thereof that can come into contact with the tab, across a joint portion joined to the metal layer, when viewed from the stacking direction of the electrode body, and the conductive member has a laminate side contact portion on the other side thereof that is opposite the joint portion.

[0020] In the battery cell according to claim 7, the conductive member has a tab-side contact portion on one side and a laminate-side contact portion on the other side, sandwiching a joint portion joined to the metal layer when viewed from the stacking direction of the electrode body. This allows the laminate-side contact portion and the tab-side contact portion to move in opposite directions with the joint portion as a fulcrum when the laminate exterior body expands, making it easy for the tab-side contact portion to come into contact with the tab.

[0021] The battery cell according to claim 8 is the battery cell according to claim 7, wherein the tab side contact portion extends in the width direction of the tab by a distance equal to or greater than the width dimension of the tab.

[0022] In the battery cell according to claim 8, when the laminate exterior body expands, the tab-side contact portion can be brought into contact with the entire area of ​​the tab in the width direction, allowing a stable short circuit to be achieved.

[0023] The battery cell of claim 9 is the same as claim 8, wherein the conductive member has a pair of bridging portions connecting the tab side contact portion and the laminate side contact portion, and each of the pair of bridging portions is joined to the metal layer at the exposed portion.

[0024] In the battery cell according to claim 9, the pair of bridging parts are joined to the metal layer, so that the joined state between the conductive member and the metal layer can be reliably maintained even when vibration, external force, etc. are input. Also, compared to a structure in which the conductive member and the metal layer are joined at only one point, the operation of the tab-side contact part when the laminate exterior body expands can be stabilized.

[0025] A battery module according to a tenth aspect of the present invention includes a battery module in which a plurality of battery cells according to any one of the first to ninth aspects are housed in an arranged state.

[0026] In the battery module according to claim 10, only the abnormal battery cell in which the laminate exterior body is expanded can be short-circuited among the plurality of battery cells.

[0027] The battery module according to claim 11 is the battery module according to claim 10, wherein the tab is bent in a direction away from the conductive member.

[0028] In the battery cell according to claim 11, by bending the tab in a direction away from the conductive member, unintentional contact between the conductive member and the tab can be prevented when the laminate exterior body is not expanded. Effect of the Invention

[0029] As described above, the battery cell and battery module according to the present invention can stably suppress overcharging only when an abnormality occurs in the battery cell. [Brief description of the drawings]

[0030] [Figure 1] 1 is a schematic plan view showing a main part of a vehicle to which a battery pack is applied; [Diagram 2] FIG. 2 is a schematic perspective view of a battery module. [Diagram 3] FIG. 2 is a plan view of the battery module with the top cover removed. [Figure 4] 3 is a schematic diagram of a battery cell accommodated in a battery module as viewed from the thickness direction. FIG. [Diagram 5] 2 is an enlarged view showing a main part of the battery cell according to the first embodiment. FIG. [Figure 6] 6 is a cross-sectional view showing a state cut along line 6-6 in FIG. 5. [Figure 7] 7 is a cross-sectional view corresponding to FIG. 6 when the battery cell is expanded. FIG. [Figure 8] FIG. 11 is an enlarged view showing a main part of a battery cell according to a second embodiment. [Figure 9] 9 is a cross-sectional view showing a state cut along line 9-9 in FIG. 8. [Figure 10]10 is a cross-sectional view corresponding to FIG. 9 when the battery cell is expanded. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] First Embodiment A battery pack 10 including a battery module 11 according to a first embodiment will be described with reference to the drawings.

[0032] (Overall configuration of vehicle 100) Fig. 1 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. As shown in Fig. 1, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) in which the battery pack 10 is mounted under the floor. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle vertical direction, the front side in the vehicle longitudinal direction, and the left side in the vehicle width direction, respectively. When describing using the front-rear, left-right, up-down directions, they refer to the front-rear in the vehicle longitudinal direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0033] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are disposed on the vehicle front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are disposed on the vehicle rear side of the battery pack 10.

[0034] The direct current output from the battery pack 10 has its voltage adjusted by a DC / DC converter 102, and is then supplied to an electric compressor 104, a PTC heater 106, an inverter 112, etc. In addition, power is supplied to a motor 108 via the inverter 112, causing the rear wheels to rotate and causing the vehicle 100 to run.

[0035] A charging port 116 is provided on the right side at the rear of the vehicle 100, and by connecting a charging plug of an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the on-board charger 114.

[0036] The arrangement and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle in which the motor 108 is mounted at the rear of the vehicle, but the present invention is not limited to this. The vehicle may be a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, the vehicle may be equipped with an in-wheel motor on each wheel.

[0037] Here, the battery pack 10 is configured to include a plurality of battery modules 11. As an example in this embodiment, ten battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle front-rear direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle front-rear direction. In addition, each battery module 11 is electrically connected.

[0038] Fig. 2 is a schematic perspective view of the battery module 11. As shown in Fig. 2, the battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is formed of an aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die castings to both ends of an aluminum alloy extrusion material by laser welding or the like.

[0039] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, which will be described later, is connected to the connector 14. In addition, bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0040] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle up-down direction is, for example, 80 mm to 110 mm.

[0041] Fig. 3 is a plan view of the battery module 11 with the top cover removed. As shown in Fig. 3, a plurality of battery cells 20 are housed in an arranged state inside the battery module 11. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to one another.

[0042] A flexible printed circuit (FPC) 21 is disposed on the battery cells 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and a thermistor 23 is provided on each of both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cells 20, and is configured to be pressed towards the battery cells 20 by the upper lid of the battery module 11.

[0043] Fig. 4 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 4, the battery cell 20 is formed in a substantially rectangular plate shape, and an electrode body 25 is housed therein. The electrode body 25 is sealed by a laminate exterior body 22 formed from a laminate material. For ease of explanation, FIG. 4 omits illustration of conductive members 30, 32, which are essential parts of the present invention. The structure of the end portion of the battery cell 20, including the conductive members 30, 32, will be described in detail later.

[0044] As an example, the battery cell 20 of this embodiment has an electrode assembly housing formed by folding and pasting an embossed sheet-like laminate exterior body 22. Note that while both a single cup embossed structure in which one place is embossed and a double cup embossed structure in which two places are embossed can be used, this embodiment uses a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0045] The upper ends of the battery cells 20 at both ends in the longitudinal direction are bent to form corners. The upper end of the battery cells 20 is also bent, and a fixing tape 24 is wound around the upper end of the battery cells 20 along the longitudinal direction.

[0046] Here, tabs (terminals) are provided at both longitudinal ends of the battery cell 20. Specifically, a positive electrode side tab 26 is provided at one longitudinal end of the battery cell 20, and a negative electrode side tab 28 is provided at the other longitudinal end of the battery cell 20.

[0047] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, the length CW2 of the area in which the electrode body is housed is, for example, 500 mm to 520 mm, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm. The thickness of the battery cell 20 is 7.0 mm to 9.0 mm, and the height TH of the terminals is 40 mm to 50 mm.

[0048] (20 battery cells) Fig. 5 is an enlarged view of a main part of the battery cell 20 according to the first embodiment. As shown in Fig. 5, the laminated exterior body 22 constituting the battery cell 20 of this embodiment is formed by coating a metal layer with resin, and exposed parts 22A where part of the metal layer is exposed are provided at both ends in the longitudinal direction of the laminated exterior body 22.

[0049] The exposed portions 22A are provided as a pair at positions offset vertically from the center in the short side direction (vertical direction) at both ends in the longitudinal direction of the laminate exterior body 22. Therefore, the exposed portions 22A are provided at positions that do not overlap with the positive electrode side tab 26 and the negative electrode side tab 28 when viewed from the stacking direction of the electrode body 25. Also, each exposed portion 22A is formed, for example, by removing a resin layer of the laminate exterior body 22 to expose a metal layer.

[0050] The electrode assembly 25 housed inside the laminated outer casing 22 is configured by alternately stacking positive electrodes 25A and negative electrodes 25B with a separator (not shown) sandwiched therebetween, and in this embodiment, the negative electrodes 25B are slightly larger than the positive electrodes 25A. When forming a battery module, the positive electrode side tab 26 is folded in the opposite direction to the positive electrode side conductive member 30 described later, and the negative electrode side tab 28 is folded in the opposite direction to the negative electrode side conductive member 32 described later. Specifically, the positive electrode side tab 26 is folded toward the back of the paper on the opposite side to the surface on which the positive electrode side conductive member 30 is provided in the stacking direction of the electrode assembly 25. The negative electrode side tab 28 is folded toward the back of the paper on the opposite side to the surface on which the negative electrode side conductive member 32 is provided in the stacking direction of the electrode assembly 25.

[0051] The positive electrode side tab 26 is a metal plate formed in a substantially rectangular shape when viewed from the stacking direction of the electrode body 25, and one end of the positive electrode side tab 26 is connected to an end of the positive electrode 25A inside the laminated exterior body 22. In addition, the other end of the positive electrode side tab 26 extends to the outside of the laminated exterior body 22.

[0052] The negative electrode side tab 28 is a metal plate formed in a substantially rectangular shape when viewed from the stacking direction of the electrode body 25, and one end of the negative electrode side tab 28 is connected to an end of the negative electrode 25B inside the laminated exterior body 22. The other end of the negative electrode side tab 28 extends to the outside of the laminated exterior body 22.

[0053] The positive electrode side conductive member 30 is provided on the positive electrode side of the battery cell 20, and is formed in a substantially rectangular frame shape when viewed from the stacking direction of the electrode body 25. Specifically, the positive electrode side conductive member 30 includes a laminate side contact portion 30A extending in the short direction of the battery cell 20 on the laminate exterior body 22, and a tab side contact portion 30B located above the positive electrode side tab 26 and substantially parallel to the laminate side contact portion 30A. The positive electrode side conductive member 30 also includes a pair of bridging portions 30C extending in the longitudinal direction of the battery cell 20 and connecting the ends of the laminate side contact portion 30A and the tab side contact portion 30B.

[0054] The laminate side contact portion 30A of the positive electrode side conductive member 30 is located closer to the end of the battery cell 20 than the positive electrode 25A and the negative electrode 25B of the electrode body 25, and is joined to the surface of the laminate exterior body 22 with an adhesive, tape, or the like. Therefore, in the event of an abnormality such as when the inside of the laminate exterior body 22 is filled with gas, the laminate side contact portion 30A is displaced as the laminate exterior body 22 expands. Note that the laminate side contact portion 30A does not have to be joined to the laminate exterior body 22. Even in this case, the laminate side contact portion 30A is pushed up as the laminate exterior body 22 expands, and is thereby displaced.

[0055] The tab side contact portion 30B of the positive side conductive member 30 is normally disposed apart from the positive side tab 26 and extends beyond the width dimension of the positive side tab 26. As shown in FIG. 6, the cross-sectional shape of the tab side contact portion 30B is formed into a substantially hat shape with the positive side tab 26 side open, so as to avoid the positive side tab 26.

[0056] 5, the pair of bridging portions 30C are overlapped with the exposed portions 22A and are joined at the exposed portions 22A to the metal layer of the laminate exterior body 22. The joining of the bridging portions 30C to the metal layer may be performed by, for example, ultrasonic bonding.

[0057] In this way, the positive electrode side conductive member 30 is electrically connected to the metal layer at the exposed portion 22A, and is disposed spaced apart from the positive electrode side tab 26. When viewed from the lamination direction of the electrode body 25, the positive electrode side conductive member 30 has one side sandwiching a joint portion joined to the metal layer as a tab side contact portion 30B that can come into contact with the positive electrode side tab 26, and the other side of the joint portion as a laminate side contact portion 30A that is disposed in a region of the laminate exterior body 22 that does not overlap with the electrode body 25.

[0058] Here, the tab side contact portion 30B of the positive electrode side conductive member 30 is configured to come into contact with the positive electrode side tab 26 as the laminate exterior body 22 expands. That is, when the laminate exterior body 22 expands, the laminate side contact portion 30A is pushed up by the laminate exterior body 22 and attempts to be displaced toward the front side of the page.

[0059] On the other hand, since the exposed portion 22A is located at the end of the laminate exterior body 22 and is joined to the pair of bridging portions 30C, the laminate exterior body 22 does not expand, or the laminate exterior body 22 expands very little. Therefore, the tab side contact portion 30B of the positive electrode side conductive member 30 is displaced to the opposite side from the laminate side contact portion 30A, that is, toward the back side of the paper, with the exposed portion 22A as a fulcrum. Therefore, as shown in Fig. 7, the tab side contact portion 30B comes into contact with the positive electrode side tab 26, and the positive electrode side tab 26 and the metal layer of the exposed portion 22A are electrically connected to each other.

[0060] On the other hand, the negative electrode side conductive member 32 is provided on the negative electrode side of the battery cell 20, and is formed in a symmetrical shape to the positive electrode side conductive member 30. Specifically, the negative electrode side conductive member 32 includes a laminate side contact portion 32A extending in the short direction of the battery cell 20 on the laminate exterior body 22, and a tab side contact portion 32B located above the negative electrode side tab 28 and approximately parallel to the laminate side contact portion 32A. The negative electrode side conductive member 32 also includes a pair of bridging portions 32C extending in the longitudinal direction of the battery cell 20 and connecting the ends of the laminate side contact portion 32A and the tab side contact portion 32B.

[0061] The laminate side contact portion 32A of the negative electrode side conductive member 32 is located closer to the end of the battery cell 20 than the positive electrode 25A and the negative electrode 25B of the electrode assembly 25, and is joined to the surface of the laminate exterior body 22 with an adhesive, tape, or the like. Therefore, in the event of an abnormality such as when the inside of the laminate exterior body 22 is filled with gas, the laminate side contact portion 32A is displaced as the laminate exterior body 22 expands. Note that the laminate side contact portion 32A does not have to be joined to the laminate exterior body 22. Even in this case, the laminate side contact portion 32A is pushed up as the laminate exterior body 22 expands, and is thereby displaced.

[0062] The tab side contact portion 32B of the negative electrode side conductive member 32 is normally disposed apart from the negative electrode side tab 28 and extends beyond the width dimension of the negative electrode side tab 28. Similarly to the positive electrode side conductive member 30, the tab side contact portion 32B has a substantially hat-shaped cross section so as to avoid the negative electrode side tab 28.

[0063] The pair of bridging portions 32C are overlapped with the exposed portions 22A and are joined at the exposed portions 22A to the metal layer of the laminate exterior body 22. The joining of the bridging portions 32C to the metal layer may be performed by, for example, ultrasonic bonding.

[0064] In this manner, the negative electrode side conductive member 32 is electrically connected to the metal layer at the exposed portion 22A, and is disposed spaced apart from the negative electrode side tab 28. Moreover, one side of the negative electrode side conductive member 32 facing the joint portion joined to the metal layer is a tab side contact portion 32B that can come into contact with the negative electrode side tab 28, and the other side facing the joint is a laminate side contact portion 32A that is disposed in a region of the laminate exterior body 22 that does not overlap with the electrode body 25.

[0065] Here, the tab side contact portion 32B of the negative electrode side conductive member 32 is configured to come into contact with the negative electrode side tab 28 as the laminate exterior body 22 expands. That is, when the laminate exterior body 22 expands, the laminate side contact portion 32A is pushed up by the laminate exterior body 22 and attempts to be displaced toward the front side of the page.

[0066] On the other hand, the tab side contact portion 32B of the negative electrode side conductive member 32 is displaced toward the opposite side to the laminate side contact portion 32A, i.e., toward the back side of the paper, with the exposed portion 22A as a fulcrum. As a result, the tab side contact portion 32B comes into contact with the negative electrode side tab 28, and the negative electrode side tab 28 and the metal layer of the exposed portion 22A are electrically connected. In this manner, when the laminate exterior body 22 expands, the positive electrode side tab 26 and the negative electrode side tab 28 are short-circuited via the positive electrode side conductive member 30, the negative electrode side conductive member 32, and the metal layer.

[0067] (action) Next, the operation of the battery cell 20 and the battery module 11 according to this embodiment will be described.

[0068] In the battery cell 20 according to this embodiment, the laminate exterior body 22 is formed of a laminate material including a metal layer, and an electrode assembly 25 is housed inside this laminate exterior body 22. A positive electrode side tab 26 is connected to a positive electrode 25A constituting the electrode assembly 25, and a negative electrode side tab 28 is connected to a negative electrode 25B, and the positive electrode side tab 26 and the negative electrode side tab 28 extend to the outside of the laminate exterior body 22. This allows the battery cell to be charged and discharged via the positive electrode side tab 26 and the negative electrode side tab 28.

[0069] Furthermore, the battery cell 20 includes a positive electrode side conductive member 30 arranged at a distance from the positive electrode side tab 26, and a negative electrode side conductive member 32 arranged at a distance from the negative electrode side tab 28, and the positive electrode side conductive member 30 and the negative electrode side conductive member 32 are each electrically connected to the metal layer of the laminate material. As the laminate exterior body 22 expands, the positive electrode side conductive member 30 comes into contact with the positive electrode side tab 26, and the negative electrode side conductive member 32 comes into contact with the negative electrode side tab 28. This causes a short circuit between the positive electrode side tab 26 and the negative electrode side tab 28, thereby preventing overcharging. When the laminate exterior body 22 returns from the expanded state to its original state, the short circuit state is released.

[0070] In this embodiment, the metal layer of the exposed portion 22A is electrically connected to the positive electrode side conductive member 30 and the negative electrode side conductive member 32 by joining them. This makes it possible to short-circuit the positive electrode side tab 26 and the negative electrode side tab 28 with a simple structure without requiring any parts for connecting the conductive members to the metal layer.

[0071] Furthermore, in this embodiment, by arranging the exposed portion 22A at a position that does not overlap with the positive electrode side tab 26 and the negative electrode side tab 28 when viewed from the stacking direction of the electrode body 25, unintentional electrical conduction between these tabs and the metal layer can be prevented.

[0072] Furthermore, in this embodiment, the positive electrode side conductive member 30 and the negative electrode side conductive member 32 are provided with tab side contact portions 30B, 32B on one side and laminate side contact portions 30A, 30B on the other side, sandwiching a joint portion joined to the metal layer. As a result, when the laminate exterior body 22 expands, the laminate side contact portions 30A, 32A and the tab side contact portions 30B, 32B move in opposite directions with the joint portion as a fulcrum, and the tab side contact portions 30B, 32B can easily come into contact with the positive electrode side tab 26 and the negative electrode side tab 28.

[0073] In addition, in this embodiment, when the laminate exterior body 22 expands, the tab side contact portion 30B can be brought into contact with the entire widthwise area of ​​the positive electrode side tab 26, and the tab side contact portion 32B can be brought into contact with the entire widthwise area of ​​the negative electrode side tab 28. This allows for stable short-circuiting.

[0074] Furthermore, in this embodiment, since the pair of bridging portions 30C are joined to the metal layer, the joined state between the positive electrode side conductive member 30 and the metal layer can be reliably maintained even when vibration or external force is input. Similarly, since the pair of bridging portions 32C are joined to the metal layer, the joined state between the negative electrode side conductive member 32 and the metal layer can be reliably maintained even when vibration or external force is input. Furthermore, compared with a structure in which the positive electrode side conductive member 30 and the negative electrode side conductive member 32 are joined to the metal layer at only one point, the operation of the tab side contact portions 30B and 32B when the laminate exterior body 22 expands can be stabilized.

[0075] Furthermore, in this embodiment, by bending the positive electrode side tab 26 in a direction away from the positive electrode side conductive member 30, it is possible to prevent unintended contact between the positive electrode side conductive member 30 and the positive electrode side tab 26 when the laminate exterior body 22 is not expanded. Similarly, by bending the negative electrode side tab 28 in a direction away from the negative electrode side conductive member 32, it is possible to prevent unintended contact between the negative electrode side conductive member 32 and the negative electrode side tab 28 when the laminate exterior body 22 is not expanded.

[0076] In the battery module 11 according to this embodiment, the battery cells 20 according to this embodiment are housed in an array. Therefore, among the multiple battery cells 20, only the abnormal battery cell 20 in which the laminated outer casing 22 is expanded can be short-circuited, and the other normal battery cells 20 can be charged and discharged.

[0077] <Second embodiment> Next, a battery cell 50 according to a second embodiment will be described with reference to the drawings. Note that the same components as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0078] Fig. 8 is an enlarged view of a main part of a battery cell 50 according to the second embodiment. Fig. 9 is a cross-sectional view taken along line 9-9 in Fig. 8, and Fig. 10 is a cross-sectional view corresponding to Fig. 9 when the battery cell 50 has expanded. As shown in Fig. 8, the laminated exterior body 22 constituting the battery cell 50 according to this embodiment is formed by coating a metal layer with resin, and exposed portions 22A in which the metal layer is partially exposed are provided at both longitudinal ends of the laminated exterior body 22.

[0079] The exposed portion 22A is provided at a position that does not overlap with the positive electrode side tab 26 and the negative electrode side tab 28 when viewed from the stacking direction of the electrode body 25. Also, each exposed portion 22A is formed, for example, by removing a resin layer of the laminate exterior body 22 to expose a metal layer.

[0080] The electrode assembly 25 housed inside the laminated outer casing 22 is constructed by alternately stacking positive electrodes 25A and negative electrodes 25B with a separator (not shown) sandwiched therebetween, and in this embodiment, the negative electrodes 25B are slightly larger than the positive electrodes 25A.

[0081] When forming a battery module, the positive electrode side tab 26 is bent away from a positive electrode side conductive member 52, which will be described later, and the negative electrode side tab 28 is bent away from a negative electrode side conductive member 54, which will be described later. In this embodiment, as an example, the positive electrode side tab 26 and the negative electrode side tab 28 are provided at positions offset downward from the center of the battery cell 50 in the up-down direction. For example, the positive electrode side tab 26 and the negative electrode side tab 28 are joined to a bus bar (not shown) by laser welding or the like.

[0082] The positive electrode side conductive member 52 includes a laminate side contact portion 52A, a tab side contact portion 52B, and a connecting portion 52C. The laminate side contact portion 52A is disposed on the laminate exterior body 22 at a position not overlapping with the electrode body 25, and is joined to the surface of the laminate exterior body 22 with an adhesive, tape, or the like. Therefore, in the event of an abnormality such as when the inside of the laminate exterior body 22 is filled with gas, the laminate side contact portion 52A is displaced as the laminate exterior body 22 expands.

[0083] The tab side contact portion 52B is disposed above the positive electrode side tab 26, outside the laminated exterior body 22. As shown in Fig. 9, the tab side contact portion 52B is bent with respect to the connecting portion 52C in a direction away from the positive electrode side tab 26, and has a shape that prevents the positive electrode side conductive member 52 and the positive electrode side tab 26 from unintentionally contacting each other when the laminated exterior body 22 is not expanded.

[0084] 8, the connecting portion 52C connects the laminate side contact portion 52A and the tab side contact portion 52B. A part of the connecting portion 52C overlaps with the exposed portion 22A to form a joint portion 52D joined to the exposed portion 22A. Therefore, one side of the positive electrode side conductive member 52 facing the joint portion 52D is the tab side contact portion 52B, and the other side facing the joint portion 52D is the laminate side contact portion 52A.

[0085] The negative electrode side conductive member 54 has substantially the same shape as the positive electrode side conductive member 52, is arranged symmetrically, and includes a laminate side contact portion 54A, a tab side contact portion 54B, and a connecting portion 54C. The laminate side contact portion 54A is arranged on the laminate exterior body 22 at a position not overlapping with the electrode body 25, and is joined to the surface of the laminate exterior body 22 with an adhesive, tape, or the like. Therefore, in the event of an abnormality such as when the inside of the laminate exterior body 22 is filled with gas, the laminate side contact portion 54A is displaced as the laminate exterior body 22 expands.

[0086] The tab side contact portion 54B is disposed above the negative electrode side tab 28 and outside the laminate exterior body 22. Similarly to the tab side contact portion 52B of the positive electrode side conductive member 52, the tab side contact portion 54B is bent with respect to the connecting portion 54C in a direction away from the negative electrode side tab 28, and has a shape that prevents unintended contact between the negative electrode side conductive member 54 and the positive electrode side tab 26 when the laminate exterior body 22 is not expanded.

[0087] 8, the connecting portion 52C connects the laminate side contact portion 52A and the tab side contact portion 52B. A part of the connecting portion 52C overlaps with the exposed portion 22A to form a joint portion 52D joined to the exposed portion 22A. Therefore, one side of the positive electrode side conductive member 52 facing the joint portion 52D is the tab side contact portion 52B, and the other side facing the joint portion 52D is the laminate side contact portion 52A.

[0088] The positive electrode side conductive member 52 and the negative electrode side conductive member 54 are configured as described above, and when the laminate outer casing 22 expands, the laminate side contact portion 52A of the positive electrode side conductive member 52 and the laminate side contact portion 54A of the negative electrode side conductive member 54 are pushed up by the laminate outer casing 22 and attempt to be displaced toward the front of the paper.

[0089] On the other hand, the tab side contact portion 52B of the positive side conductive member 52 and the tab side contact portion 54B of the negative side conductive member 54 are displaced to the opposite side to the laminate side contact portion 52A and the laminate side contact portion 54A, i.e., toward the depth of the page, with the exposed portion 22A as a fulcrum. Therefore, as shown in Fig. 10, the tab side contact portion 52B of the positive side conductive member 52 comes into contact with the positive side tab 26, and the positive side tab 26 and the metal layer of the exposed portion 22A are electrically connected to each other.

[0090] Like the tab side contact portion 52B, the tab side contact portion 54B of the negative electrode side conductive member 54 comes into contact with the negative electrode side tab 28, and electrical conduction is established between the negative electrode side tab 28 and the metal layer of the exposed portion 22A. In this manner, when the laminate exterior body 22 expands, the positive electrode side tab 26 and the negative electrode side tab 28 are short-circuited via the positive electrode side conductive member 52, the negative electrode side conductive member 54, and the metal layer.

[0091] (Conductive material) The shape of the conductive member is not limited to the shapes shown in the first and second embodiments. Examples of the shape of the conductive member include a rectangular shape, a circular shape, a trapezoidal shape, and a triangular shape.

[0092] (action) Next, the operation of the battery cell 50 according to this embodiment will be described.

[0093] In the battery cell 50 according to this embodiment, the positive electrode tab 26 and the negative electrode tab 28 can be short-circuited with a simpler structure than in the first embodiment. Other operations are similar to those of the first embodiment.

[0094] The battery cell 20 and the battery module 11 according to the present embodiment have been described above, but the present invention is not limited thereto and may be embodied in various forms without departing from the spirit and scope of the present invention. In the above embodiment, the positive electrode side conductive member 30 and the metal layer are joined at the exposed portion 22A, but the present invention is not limited thereto. For example, the exposed portion 22A may not be provided on the laminated exterior body 22, and a terminal may be extended from the metal layer to the outside of the laminated exterior body 22, and the terminal and the positive electrode side conductive member 30 may be joined.

[0095] Regarding the above embodiment, the following notes are disclosed.

[0096] (Appendix 1) A laminate exterior body formed by a laminate material including a metal layer; An electrode assembly that is configured by alternately stacking positive electrodes and negative electrodes with separators sandwiched therebetween and is housed inside the laminate exterior body; a pair of tabs connected to the positive electrode and the negative electrode, respectively, and extending to the outside of the laminate exterior body; a pair of conductive members electrically connected to the metal layer, spaced apart from the tabs, and coming into contact with the pair of tabs as the laminate exterior body expands; A battery cell having (Appendix 2) The laminate exterior body has an exposed portion where the metal layer is exposed, 2. The battery cell of claim 1, wherein the pair of conductive members are joined to the metal layer at the exposed portions. (Appendix 3) 3. The battery cell according to claim 2, wherein the exposed portion is provided at a position that does not overlap with the tab when viewed from the stacking direction of the electrode body. (Appendix 4) 4. The battery cell according to claim 1, wherein the conductive member is provided at a position where it does not overlap with the electrode body when viewed from the stacking direction of the electrode body. (Appendix 5) 5. The battery cell according to claim 1, wherein at least a portion of the conductive member is disposed in a position overlapping with the tab when viewed from the stacking direction of the electrode assembly. (Appendix 6) 5. The battery cell according to claim 1, wherein the tab entirely overlaps with the conductive member when viewed from the stacking direction of the electrode assembly. (Appendix 7) 3. A battery cell as described in Appendix 2, wherein the conductive member has a tab-side contact portion on one side thereof that can come into contact with the tab, across a joint portion joined to the metal layer, when viewed from the stacking direction of the electrode body, and the conductive member has a laminate-side contact portion on the other side thereof that is opposite the joint portion. (Appendix 8) 8. The battery cell according to claim 7, wherein the tab-side contact portion extends in a width direction of the tab to a width dimension of the tab or greater. (Appendix 9) the conductive member includes a pair of bridge portions connecting the tab-side contact portion and the laminate-side contact portion, 9. The battery cell of claim 8, wherein each of the pair of bridging portions is joined to the metal layer at the exposed portion. (Appendix 10) A battery module in which a plurality of battery cells according to any one of claims 1 to 9 are housed in an arranged state. (Appendix 11) 11. The battery module of claim 10, wherein the tab is bent in a direction away from the conductive member. [Explanation of symbols]

[0097] 11 Battery module 20, 50 battery cells 22 Laminate exterior body 22A Exposed part 25 Electrode body 25A positive electrode 25B negative electrode 26 Positive tab 28 Negative tab 30, 52 Positive electrode conductive member 32, 54 Negative electrode conductive member

Claims

1. A laminate exterior body formed by a laminate material including a metal layer; An electrode assembly that is configured by alternately stacking positive electrodes and negative electrodes with separators sandwiched therebetween and is housed inside the laminate exterior body; a pair of tabs connected to the positive electrode and the negative electrode, respectively, and extending to the outside of the laminate exterior body; a pair of conductive members electrically connected to the metal layer, spaced apart from the tabs, and coming into contact with the pair of tabs as the laminate exterior body expands; A battery cell having

2. The laminate exterior body has an exposed portion where the metal layer is exposed, The battery cell according to claim 1 , wherein the pair of conductive members are joined to the metal layer at the exposed portions.

3. The battery cell according to claim 2 , wherein the exposed portion is provided at a position that does not overlap with the tab when viewed from the stacking direction of the electrode body.

4. The battery cell according to claim 1 , wherein the conductive member is provided at a position that does not overlap the electrode body when viewed from a stacking direction of the electrode body.

5. The battery cell according to claim 1 , wherein at least a portion of the conductive member is disposed in a position overlapping with the tab when viewed from the stacking direction of the electrode assemblies.

6. The battery cell according to claim 1 , wherein the tab entirely overlaps with the conductive member when viewed from the stacking direction of the electrode assemblies.

7. 3. The battery cell according to claim 2, wherein the conductive member has a tab side contact portion on one side thereof that can come into contact with the tab, the tab side contact portion being sandwiched between the conductive member and the metal layer when viewed from the stacking direction of the electrode body, and the conductive member has a laminate side contact portion on the other side thereof that is opposite the joint portion.

8. The battery cell according to claim 7 , wherein the tab-side contact portion extends in a width direction of the tab by a width dimension of the tab or more.

9. the conductive member includes a pair of bridge portions connecting the tab-side contact portion and the laminate-side contact portion, The battery cell according to claim 8 , wherein each of the pair of bridge portions is joined to the metal layer at the exposed portion.

10. A battery module in which a plurality of battery cells according to any one of claims 1 to 9 are housed in an arranged state.

11. The battery module according to claim 10 , wherein the tab is bent in a direction away from the conductive member.

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