Battery stack and battery pack

Abstract

To provide a battery stack and a battery pack capable of suppressing deformation of a conductive member.SOLUTION: In a battery stack according to the present invention, a conductive member is disposed, via an adhesive member, at an end in a first direction of a battery module. Viewing from a second direction which is a direction perpendicular to the first direction, the conductive member has: a first flat plate part; a second flat plate part; and a connection part located between the first flat plate part and the second flat plate part. The first flat plate part is located further on the battery module side in the first direction than the second flat plate part. The Young's modulus of the adhesive member located between the first flat plate part and the battery module is lower than that of the adhesive member located between the second flat plate part and the battery module.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery stack and a battery pack. [Background technology]

[0002] Patent Document 1 discloses flat current collector plates that collect current as module positive electrodes and module negative electrodes of bipolar batteries stacked in a first direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-175828 Summary of the Invention [Problem to be solved by the invention]

[0004] When multiple types of adhesive materials are used to bond the conductive current collector plate to the battery module and to bond the current collector plate to the battery pack case, the Young's modulus varies depending on the adhesive material, which can cause variations in the normal stress on the current collector plate, battery module, and battery pack case, which can result in deformation of the current collector plate.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a battery stack and a battery pack that can suppress deformation of conductive members. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the battery stack of the present invention is a battery stack in which a conductive member is arranged at the end of a battery module in a first direction via an adhesive member, and the conductive member has, when viewed from a second direction that is perpendicular to the first direction, a first flat plate portion, a second flat plate portion, and a connection portion located between the first flat plate portion and the second flat plate portion, and the first flat plate portion is located closer to the battery module in the first direction than the second flat plate portion, and the adhesive member located between the first flat plate portion and the battery module has a smaller Young's modulus than the adhesive member located between the second flat plate portion and the battery module.

[0007] This makes it possible to suppress deformation of the conductive member caused by the difference in the compressive load required between the adhesive member located between the first flat plate portion and the battery module and the adhesive member located between the second flat plate portion and the battery module.

[0008] In the above battery stack, the connection portion may extend in the first direction.

[0009] This makes it possible to suppress the adhesive member located between the second flat plate portion and the battery module from spreading in the second direction.

[0010] Furthermore, the battery pack of the present invention is a battery pack having a case that houses the above-mentioned battery stack, wherein the conductive member is arranged in the case via the adhesive member and the insulating member in a direction away from the battery module in the first direction, and the adhesive member located between the first flat plate portion and the insulating member has a smaller Young's modulus than the adhesive member located between the second flat plate portion and the insulating member.

[0011] This makes it possible to suppress deformation of the conductive member that occurs due to the difference in compressive load required for the adhesive member on both sides of the conductive member.

[0012] In addition, in the above battery pack, a temperature measuring element for measuring the temperature of the battery module may be provided at least either between the first flat plate portion and the insulating member or between the second flat plate portion and the battery module.

[0013] This makes it possible to measure the temperature of the battery module by the temperature measuring element while suppressing an increase in the overall height of the battery pack due to the thickness of the temperature measuring element in the first direction.

[0014] In addition, in the above battery pack, the conductive member may be configured so that the end portion in a third direction, which is a direction perpendicular to both the first direction and the second direction, has lower bending rigidity than the central portion in the third direction.

[0015] This improves the ability of the conductive member to follow the battery module at the end in the third direction between the battery module and the conductive member, which is prone to separation due to vibration in the first direction, and prevents the conductive member from separating from the battery module. [Effects of the Invention]

[0016] The battery stack and battery pack according to the present invention have the advantage of being able to suppress deformation of the conductive members. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a battery pack according to a first embodiment. [Figure 2] FIG. 2 is an enlarged view showing a part of the lower portion of the battery stack in the battery pack according to the first embodiment. [Figure 3] FIG. 3 is an enlarged view showing an end portion in the third direction at the bottom of the battery stack in the battery pack according to the second embodiment. [Figure 4] FIG. 4 is an enlarged view showing the central portion in the third direction at the bottom of the battery stack in the battery pack according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] (Embodiment 1) A battery stack and a battery pack according to a first embodiment of the present invention will be described below, but the present invention is not limited to this embodiment.

[0019] FIG. 1 is a cross-sectional view showing a schematic configuration of a battery pack 1 according to the first embodiment.

[0020] The battery pack 1 in the first embodiment is mounted on an electric vehicle and serves as, for example, a power supply source that supplies power to a motor that is a drive source of the electric vehicle. The battery pack 1 according to the first embodiment includes a case 2 that is composed of an upper case 21 and a lower case 22. A battery stack 3 that is a power storage device is housed inside the case 2. The upper case 21 and the lower case 22 face each other in a first direction (the direction of arrow X in FIG. 1) of the battery pack 1 (battery stack 3). The direction of arrow Y in FIG. 1 is a second direction that is perpendicular to the first direction. The direction of arrow Z in FIG. 1 is a third direction that is perpendicular to both the first direction and the second direction.

[0021] The battery stack 3 includes a plurality of battery modules 31A, 31B, 31C, and 31D, a plurality of current collector plates 33A and 33B, a current-conducting plate 34, and a plurality of cooling plates 35A and 35B. The battery stack 3 is a stacked body formed by stacking the current collector plate 33A, the battery module 31A, the cooling plate 35A, the battery module 31B, the current-conducting plate 34, the battery module 31C, the cooling plate 35B, the battery module 31D, and the current collector plate 33B in this order from the bottom (the lower case 22 side) to the top (the upper case 21 side) in a first direction. That is, in the battery stack 3 according to the first embodiment, the current collector plates 33A and 33B are disposed at the bottom and top of the battery stack 3 in the stacking direction of the battery modules 31A, 31B, 31C, and 31D (battery stack 3). In the battery stack 3 according to the first embodiment, a current-carrying plate 34 is disposed between the battery modules 31B and 31C adjacent to each other in the stacking direction. In the battery stack 3 according to the first embodiment, cooling plates 35A and 35B are disposed between the battery modules 31A and 31B adjacent to each other in the stacking direction and between the battery modules 31C and 31D adjacent to each other in the stacking direction.

[0022] Each of the battery modules 31A, 31B, 31C, and 31D has a plurality of battery cells. The battery cells are configured, for example, by lithium ion batteries, bipolar electrode bodies, or monopolar electrode bodies. Note that the number of battery modules in the battery stack 3 according to the first embodiment is not limited to four, i.e., the battery modules 31A, 31B, 31C, and 31D.

[0023] Current collector plate 33A and current collector plate 33B are positive and negative current collector plates that serve as conductive members electrically connected to adjacent battery modules 31A and 31D. Current-carrying plate 34 electrically connects battery modules 31B and 31C. Cooling plates 35A and 35B are made of metal such as aluminum or copper and electrically connect battery modules 31A and 31B and battery modules 31C and 31D, respectively.

[0024] In the battery pack 1 according to the first embodiment, an insulating sheet 32A, which is a plate-shaped insulating member, is disposed between the lower case 32 and the current collector plate 33A. In addition, an insulating sheet 32B, which is a plate-shaped insulating member, is disposed between the upper case 31 and the current collector plate 33B.

[0025] FIG. 2 is an enlarged view showing a part of the lower portion of the battery stack 3 in the battery pack 1 according to the first embodiment.

[0026] 2, in the battery pack 1 according to the first embodiment, a current collector 33A is disposed at the lower end of the battery module 31A in the first direction via an adhesive member (first adhesive member 41 or second adhesive member 42). The thickness of the current collector 33A is, for example, approximately 0.5 mm to 3.4 mm.

[0027] When viewed from the second direction, the current collector plate 33A has a first flat plate portion 331A, a second flat plate portion 332A, and a connection portion 333A located between the first flat plate portion 331A and the second flat plate portion 332A. The first flat plate portion 331A is located closer to the battery module 31A in the first direction than the second flat plate portion 332A. The distance between the first flat plate portion 331A and the battery module 31A in the first direction is, for example, 1 mm to 2 mm. The distance between the second flat plate portion 332A and the battery module 31A in the first direction is, for example, 1 mm to 2 mm.

[0028] In the battery pack 1 according to the first embodiment, a first adhesive member 41 is disposed between the first flat plate portion 331A of the current collector 33A and the battery module 31A to bond the first flat plate portion 331A to the battery module 31A. In the battery pack 1 according to the first embodiment, a second adhesive member 42 is disposed between the second flat plate portion 332A of the current collector 33A and the battery module 31A to bond the second flat plate portion 332A to the battery module 31A.

[0029] The first adhesive member 41 is, for example, an epoxy-based conductive adhesive having higher electrical conductivity than the second adhesive member 42. The second adhesive member 42 is, for example, an epoxy-based thermally conductive adhesive having higher thermal conductivity than the first adhesive member 41. The thickness of the first adhesive member 41 is thinner than the thickness of the second adhesive member 42. This reduces the electrical resistance between the first flat plate portion 331A and the battery module 31A via the first adhesive member 41, thereby increasing the electrical conductivity. On the other hand, the thickness of the second adhesive member 42 is thicker than the thickness of the first adhesive member 41, so that the second adhesive member 42 can securely fasten the second flat plate portion 332A and the battery module 31A together.

[0030] The distance between the first adhesive member 41 and the second adhesive member 42 in the third direction is, for example, 0 mm or more and 10 mm or less. The length of the first adhesive member 41 and the second adhesive member 42 in the width direction (the direction in which the first adhesive member 41 and the second adhesive member 42 are aligned) is, for example, 3 mm or more and 20 mm or less.

[0031] In the battery pack 1 according to the first embodiment, the first adhesive member 41 has a smaller Young's modulus than the second adhesive member 42. This makes it possible to suppress deformation of the current collector plate 33A caused by the difference in the compressive load required for the first adhesive member 41 and the second adhesive member 42. Furthermore, by increasing the distance between the battery module 31A and the second adhesive member 42, which has a relatively large Young's modulus and is less likely to deform, it is possible to suppress deformation of the current collector plate 33A due to non-uniform normal stress.

[0032] Furthermore, since the connection portion 333A of the current collector plate 33A extends in the first direction, it is possible to suppress the second adhesive member 42 located between the second flat plate portion 332A and the battery module 31A from spreading in the second direction.

[0033] In the battery pack 1 according to the first embodiment, the current collector 33A is disposed on the lower case 22 in a direction away from the battery module 31A in the first direction, via the first adhesive member 41 or the second adhesive member 42 and the insulating sheet 32A. The first adhesive member 41, which is positioned between the first flat plate portion 331A of the current collector 33A and the insulating sheet 32A, has a smaller Young's modulus than the second adhesive member 42, which is positioned between the second flat plate portion 332A of the current collector 33A and the insulating sheet 32A. This makes it possible to suppress deformation of the current collector 33A and the battery module 31A that occurs due to the difference in compressive load required by the first adhesive member 41 and the second adhesive member 42 on both sides of the current collector 33A in the first direction.

[0034] Furthermore, in the battery pack 1 according to the first embodiment, a thermistor 5, which is a temperature measuring element for measuring the temperature of the battery module 31A, may be provided at least either between the first flat plate portion 331A and the insulating sheet 32A or between the second flat plate portion 332A and the battery module 31A. In Fig. 2, the thermistor 5 is provided between the second flat plate portion 332A and the battery module 31A. This allows the battery pack 1 according to the first embodiment to measure the temperature of the battery module 31A using the thermistor 5 while suppressing an increase in the overall height of the battery pack 1 due to the thickness of the thermistor 5 in the first direction.

[0035] (Embodiment 2) A battery stack and a battery pack according to a second embodiment of the present invention will be described below. Note that in the second embodiment, the same configuration as in the first embodiment will not be described as appropriate.

[0036] Fig. 3 is an enlarged view showing an end portion in the third direction at the lower part of the battery stack 3 in the battery pack 1 according to embodiment 2. Fig. 4 is an enlarged view showing an end portion in the third direction at the lower part of the battery stack 3 in the battery pack 1 according to embodiment 2.

[0037] In the battery pack 1 according to the second embodiment, the current collector 33A of the battery stack 3 is configured so that the end portions in the third direction have lower bending rigidity than the central portion in the third direction. Specifically, in the battery pack 1 according to the second embodiment, the first flat plate portion 331A or the second flat plate portion 332A of the current collector 33A is configured so that the end portions in the third direction are longer in the third direction than the central portion in the third direction. For example, in FIGS. 3 and 4, the second flat plate portion 332A of the current collector 33A is configured so that the end portions in the third direction are longer in the third direction than the central portion in the third direction.

[0038] This improves the ability of the current collector 33A to follow the battery module 31A at the end in the third direction between the battery module 31A and the current collector 33A, where the current collector 33A is likely to separate due to vibration in the first direction, etc. In the battery pack 1 according to the second embodiment, therefore, it is possible to prevent the current collector 33A from separating from the battery module 31A at the end in the third direction of the battery stack 3 due to vibration of the battery pack 1 or the like in the first direction.

[0039] Alternatively, the connecting portion 333A may be configured to be longer in the first direction at the center of the current collector 33A in the third direction than at the ends in the third direction, thereby increasing the bending rigidity of the center of the current collector 33A in the third direction compared to the ends in the third direction. In this case, the distance in the first direction between the first flat plate portion 331A and the battery module 31A at the center of the current collector 33A in the third direction is set to, for example, 3 mm to 4 mm. Furthermore, the distance in the first direction between the second flat plate portion 332A and the battery module 31A at the center of the current collector 33A in the third direction is set to, for example, 3 mm to 4 mm. [Explanation of symbols]

[0040] 1 battery pack 2 cases 3 Battery stack 5 Thermistor 21 Upper Case 22 Lower case 31A, 31B, 31C, 31D Battery Module 32A, 32B Insulation sheet 33A, 33B Current collecting plate 34 Current carrying board 35A,35B Cooling plate 331A First plate section 332A Second plate section 333A Connection

Claims

1. A battery stack in which a conductive member is disposed via an adhesive member at an end of a battery module in a first direction, the conductive member has, when viewed from a second direction that is a direction perpendicular to the first direction, a first flat plate portion, a second flat plate portion, and a connection portion located between the first flat plate portion and the second flat plate portion; the first flat plate portion is located closer to the battery module in the first direction than the second flat plate portion; a battery stack, characterized in that the adhesive member positioned between the first flat plate portion and the battery module has a smaller Young's modulus than the adhesive member positioned between the second flat plate portion and the battery module.

2. The battery stack according to claim 1 , wherein the connection portion extends in the first direction.

3. A battery pack including a case that houses the battery stack according to claim 1 or 2, the conductive member is disposed in the case via the adhesive member and the insulating member in a direction away from the battery module in the first direction; a battery pack, characterized in that the adhesive member positioned between the first flat plate portion and the insulating member has a Young's modulus smaller than that of the adhesive member positioned between the second flat plate portion and the insulating member;

4. 4. The battery pack according to claim 3, wherein a temperature measuring element for measuring the temperature of the battery module is provided at least either between the first flat plate portion and the insulating member or between the second flat plate portion and the battery module.

5. 5. The battery pack according to claim 4, wherein the conductive member has a lower bending rigidity at its end in a third direction, which is a direction perpendicular to both the first direction and the second direction, than at its central portion in the third direction.

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