Power storage module

Abstract

To provide a power storage module that can restrain electrolyte leakage from a liquid injection port provided at a middle point in a stacking direction when a plurality of liquid injection ports arranged side by side in the stacking direction are sealed with a single sealing member.SOLUTION: A power storage module 100 includes a plurality of stacked battery cells 10a, a plurality of liquid injection ports (20a, 20c, 20e), and a seal member 30. The seal member 30 seals each of three adjacent liquid injection ports (20a, 20c, 20e). The liquid injection port 20e (third liquid injection port) is disposed between the liquid injection port 20a (first liquid injection port) and the liquid injection port 20c (second liquid injection port). The melting amount of the liquid injection port 20e due to welding to the seal member 30 is greater than the melting amount of each of the liquid injection port 20a and the liquid injection port 20c due to welding to the seal member 30.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a power storage module.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2023-080893 (Patent Document 1) discloses a power storage module in which a plurality of power storage cells are stacked in one direction. The power storage module includes a liquid injection member. The liquid injection member is provided with liquid injection ports for injecting an electrolytic solution into each power storage cell. The liquid injection ports are sealed by welding a sealing member to each liquid injection port.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although not described in the above Patent Document 1, there are cases where liquid injection ports arranged in one direction (stacking direction) are sealed by a single sealing member (sealing member). In this configuration, due to the height variation of a plurality of liquid injection ports sealed by a common sealing member, it is conceivable that the intermediate liquid injection port and the sealing member in the stacking direction are not welded, and a gap is formed between the intermediate liquid injection port and the sealing member. As a result, the electrolytic solution may leak from the intermediate liquid injection port.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a power storage module capable of suppressing leakage of an electrolytic solution from a liquid injection part provided in the middle in the stacking direction when a plurality of liquid injection ports arranged in the stacking direction are sealed by a single sealing member.

Means for Solving the Problems

[0006] A power storage module according to one aspect of the present disclosure includes a plurality of battery cells stacked in a stacking direction, a plurality of liquid injection ports connected to different battery cells among the plurality of battery cells and arranged side by side in the stacking direction, and a sealing member for sealing the plurality of liquid injection ports. Each of the plurality of liquid injection ports protrudes from the connected battery cell in a direction intersecting the stacking direction. The sealing member seals each of at least three liquid injection ports adjacent to each other in the stacking direction by being welded to each of the at least three liquid injection ports. The at least three liquid injection ports include a first liquid injection port, a second liquid injection port, and at least one third liquid injection port. The first liquid injection port is arranged on one side most in the stacking direction among the at least three liquid injection ports. The second liquid injection port is arranged on the other side most in the stacking direction among the at least three liquid injection ports. The at least one third liquid injection port is arranged between the first liquid injection port and the second liquid injection port in the stacking direction. The melting amount of the at least one third liquid injection port due to welding with the sealing member is larger than the melting amount of each of the first liquid injection port and the second liquid injection port due to welding with the sealing member.

[0007] In the power storage module according to one aspect of the present disclosure, as described above, the melting amount of the at least one third liquid injection port is larger than the melting amount of each of the first liquid injection port and the second liquid injection port. Thereby, the at least one third liquid injection port can be more reliably welded to the sealing member. As a result, it is possible to suppress the formation of a gap between the at least one third liquid injection port and the sealing member. Thereby, when a plurality of liquid injection ports arranged in the stacking direction are sealed by a single sealing member, it is possible to suppress the leakage of the electrolytic solution from the at least one third liquid injection port provided in the middle in the stacking direction.

Effects of the Invention

[0008] According to the present disclosure, when a plurality of liquid injection ports arranged in the stacking direction are sealed by a single sealing member, it is possible to suppress the leakage of the electrolytic solution from the liquid injection port provided in the middle in the stacking direction.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated.

[0011] <Configuration of Power Storage Module> FIG. 1 is a diagram showing the configuration of a power storage module 100 according to the present embodiment. The power storage module 100 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. Note that the power storage module 100 may be used other than in vehicles.

[0012] The power storage module 100 includes a module laminate 10, a plurality of liquid injection members 20, and a plurality of seal members 30. The module laminate 10 includes a plurality of battery cells 10a (only three are shown in FIG. 1) and a fixing member 15. The plurality of battery cells 10a are stacked in the Z direction. Note that the Z direction is an example of the "stacking direction" of the present disclosure.

[0013] The liquid injection member 20 is a member for injecting electrolytic solution into the module laminate 10. Thereby, the electrolytic solution penetrates into the separator 14 described later. A plurality of liquid injection members 20 are arranged side by side in the X direction on the side surface 1 on the Y1 side of the module laminate 10. Each of the plurality of liquid injection members 20 is sealed by a seal member 30. The liquid injection member 20 protrudes from the module laminate 10 (side surface 1) to the Y1 side in the Y direction orthogonal to the Z direction. Note that the liquid injection member 20 may protrude in a direction that intersects without being orthogonal to the Z direction.

[0014] The liquid injection member 20 is provided with a liquid injection port 20a, a liquid injection port 20c, and a liquid injection port 20e that are adjacent to each other in the Z direction. The liquid injection port 20a, the liquid injection port 20c, and the liquid injection port 20e are integrally formed in the liquid injection member 20. The electrolytic solution is introduced into each of the liquid injection port 20a, the liquid injection port 20c, and the liquid injection port 20e. That is, three electrolytic solution injection ports (20a, 20c, 20e) are formed in one liquid injection member 20. Note that the liquid injection port 20a and the liquid injection port 20c are examples of the "first liquid injection port" and the "second liquid injection port" of the present disclosure, respectively. The liquid injection port 20e is an example of the "third liquid injection port" of the present disclosure.

[0015] The liquid injection port 20a, the liquid injection port 20c, and the liquid injection port 20e are arranged side by side in the Z direction. They are arranged in the order of the liquid injection port 20a, the liquid injection port 20e, and the liquid injection port 20c from the Z1 side.

[0016] The liquid injection port 20a, the liquid injection port 20c, and the liquid injection port 20e are each connected to a different battery cell 10a. Specifically, the liquid injection port 20a is connected to the battery cell 10a arranged on the most Z1 side among the three battery cells 10a laminated in the Z direction. The liquid injection port 20c is connected to the battery cell 10a arranged on the most Z2 side among the three battery cells 10a laminated in the Z direction. The liquid injection port 20e is connected to the battery cell 10a arranged at the center in the Z direction among the three battery cells 10a laminated in the Z direction. Each of the liquid injection port 20a, the liquid injection port 20c, and the liquid injection port 20e protrudes to the Y1 side from the battery cell 10a to which (itself) is connected.

[0017] Note that the injection port being connected to the battery cell means that the space inside the injection port (S1 to S3 described later) communicates with the space where the battery cell 10a is provided.

[0018] The injection ports 20a, 20c, and 20e are each provided with openings 20b, 20d, and 20f into which the electrolytic solution is introduced.

[0019] The sealing member 30 seals the injection ports 20a, 20c, and 20e. Specifically, the sealing member 30 is arranged to close the openings 20b, 20d, and 20f. That is, the three openings (20b, 20d, and 20f) are sealed by one sealing member 30. The sealing member 30 is formed of a sheet-like resin material or the like formed to extend in the Z direction.

[0020] The sealing member 30 is welded to the injection member 20 (each of the injection ports 20a, 20c, and 20e).

[0021] FIG. 2 is a cross-sectional view of the power storage module 100 taken along the line II-II of FIG. 1. Each of the plurality of battery cells 10a includes a current collector 11, a positive electrode active material layer 12, a negative electrode active material layer 13, and a separator 14. The battery cell 10a is composed of a laminate in which the current collector 11, the positive electrode active material layer 12, the separator 14, the negative electrode active material layer 13, and the current collector 11 are laminated in this order from the Z2 side. Note that the power storage module 100 is a bipolar type power storage module.

[0022] The fixing member 15 fixes the peripheral edges of the plurality of current collectors 11 to each other. The fixing member 15 is formed of, for example, resin or the like. The fixing member 15 is provided with a communication port 15a that communicates the inside of the battery cell 10a with the injection ports (20a, 20c, 20e).

[0023] The liquid injection member 20 is fixed to the fixing member 15. The liquid injection member 20 is fixed to the fixing member 15 such that each liquid injection port (20a, 20c, 20e) surrounds the communication port 15a when viewed from the Y1 side.

[0024] As shown in FIG. 2, the liquid injection member 20 is provided with a side wall 21, a side wall 22, a partition wall 23, and a partition wall 24. The side wall 21 is a wall portion constituting the liquid injection port 20a. The side wall 21 is disposed at the end portion of the liquid injection member 20 on the Z1 side. The side wall 22 is a wall portion constituting the liquid injection port 20c. The side wall 22 is disposed at the end portion of the liquid injection member 20 on the Z2 side.

[0025] The partition wall 23 is a wall portion constituting each of the liquid injection port 20a and the liquid injection port 20e. The partition wall 23 is a wall portion that separates the space S1 (space through which the electrolytic solution flows) of the liquid injection port 20a from the space S3 (space through which the electrolytic solution flows) of the liquid injection port 20e. The partition wall 24 is a wall portion constituting each of the liquid injection port 20c and the liquid injection port 20e. The partition wall 24 is a wall portion that separates the space S2 (space through which the electrolytic solution flows) of the liquid injection port 20c from the space S3 of the liquid injection port 20e.

[0026] The seal member 30 is welded to the end portion 21a on the Y1 side of the side wall 21. The seal member 30 is welded to the end portion 22a on the Y1 side of the side wall 22. The seal member 30 is welded to the end portion 23a on the Y1 side of the partition wall 23. The seal member 30 is welded to the end portion 24a on the Y1 side of the partition wall 24.

[0027] In the space S1, a lump portion 21b melted and solidified from the end portion 21a remains due to the welding of the side wall 21 and the seal member 30. Further, in the space S1, a lump portion 23b melted and solidified from the end portion 23a remains due to the welding of the partition wall 23 and the seal member 30.

[0028] In the space S2, a lump portion 22b melted and solidified from the end portion 22a remains due to the welding of the side wall 22 and the seal member 30. Further, in the space S2, a lump portion 24b melted and solidified from the end portion 24a remains due to the welding of the partition wall 24 and the seal member 30.

[0029] In the space S3, there remains a lump portion 23c that has melted and solidified from the end portion 23a due to the welding of the partition wall 23 and the seal member 30. Also, in the space S3, there remains a lump portion 24c that has melted and solidified from the end portion 24a due to the welding of the partition wall 24 and the seal member 30.

[0030] Here, in a conventional power storage module, due to the height variation of a plurality of liquid injection ports sealed by a common seal member, it is conceivable that the intermediate liquid injection port and the seal member in the stacking direction are not welded, and a gap is formed between the intermediate liquid injection port and the seal member. As a result, the electrolytic solution may leak from the intermediate liquid injection port.

[0031] Therefore, in the present embodiment, the melting amount of the liquid injection port 20e due to welding with the seal member 30 is larger than the melting amount of each of the liquid injection ports 20a and 20c due to welding with the seal member 30. Specifically, the total volume of the lump portion 23c and the lump portion 24c (the volume of the lump portion in the space S3) is larger than each of the total volume of the lump portion 21b and the lump portion 23b (the volume of the lump portion in the space S1), and the total volume of the lump portion 22b and the lump portion 24b (the volume of the lump portion in the space S2). Note that the volume of each of the lump portion 23b, the lump portion 23c, the lump portion 24b, and the lump portion 24c is larger than the volume of each of the lump portion 21b and the lump portion 22b.

[0032] Thereby, it is possible to suppress the melting amount of the liquid injection port 20e from becoming insufficient, so that it is possible to suppress the formation of a gap between the liquid injection port 20e and the seal member 30. As a result, it is possible to suppress the electrolytic solution introduced into the liquid injection port 20e from leaking to the liquid injection ports 20a and 20c. Thereby, it is possible to suppress the conduction (liquid connection) of the battery cells 10a through the electrolytic solution.

[0033] Also, since the volume of the lump portion is controlled as described above, the volume of the remaining space in the space S3 (the volume of the portion without the lump portion) is smaller than each of the volume of the remaining space in the space S1 and the volume of the remaining space in the space S2.

[0034] Figure 3 is an exploded perspective view of the power storage module 100 before the sealing member 30 is welded to the liquid injection member 20. As shown in Figure 3, each of the partition walls 23 and 24 protrudes toward the Y1 side from each of the side walls 21 and 22.

[0035] The liquid injection port 20a (opening 20b) has a width W1 in the X direction. The liquid injection port 20c (opening 20d) has a width W2 in the X direction. The liquid injection port 20e (opening 20f) has a width W3 in the X direction. The width W1, the width W2, and the width W3 are equal.

[0036] Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3. The side walls 21 and 22 each have a length L1 and a length L2 in the Y direction. The length L1 is equal to the length L2.

[0037] The partition walls 23 and 24 each have a length L3 and a length L4 in the Y direction. The length L3 is equal to the length L4. Each of the length L3 and the length L4 is greater than each of the length L1 and the length L2.

[0038] The liquid injection port 20a (opening 20b, see Figure 3) has a width W11 in the Z direction. The liquid injection port 20c (opening 20d, see Figure 3) has a width W12 in the Z direction. The liquid injection port 20e (opening 20f, see Figure 3) has a width W13 in the Z direction. The width W11, the width W12, and the width W13 are equal.

[0039] The side wall 21 has a thickness t1 in the Z direction. The side wall 22 has a thickness t2 in the Z direction. The partition wall 23 has a thickness t3 in the Z direction. The partition wall 24 has a thickness t4 in the Z direction. The thickness t1, the thickness t2, the thickness t3, and the thickness t4 are equal.

[0040] After the electrolytic solution is introduced into each liquid injection port (20a, 20c, 20e), the seal member 30 is welded to the liquid injection member 20. At this time, the seal member 30 is pressed against the liquid injection member 20 while being heated. As a result, the end portions (such as 21a, 22a, 23a, and 24a on the Y1 side of the liquid injection member 20, see FIG. 2) are melted.

[0041] As described above, in the present embodiment, the melting amount of the liquid injection port 20e due to welding with the seal member 30 is larger than the melting amount of each of the liquid injection ports 20a and 20c due to welding with the seal member 30. Thereby, it is possible to suppress the formation of a gap between the liquid injection port 20e and the seal member 30 due to insufficient welding between the liquid injection port 20e and the seal member 30. As a result, it is possible to suppress the electrolytic solution introduced into the liquid injection port 20e from leaking from the liquid injection port 20e to the outside (such as the liquid injection ports 20a and 20c) through the above gap.

[0042] In the above embodiment, an example in which a plurality of liquid injection ports (20a, 20c, 20e) are integrally formed is shown, but the present disclosure is not limited to this. The plurality of liquid injection ports may be provided separately from each other.

[0043] For example, in the power storage module 200 shown in FIG. 5, a liquid injection member 120 is provided. The liquid injection member 120 includes a liquid injection port 120a, a liquid injection port 120c, and a liquid injection port 120e. Each of the liquid injection port 120a, the liquid injection port 120c, and the liquid injection port 120e has a rectangular cylindrical shape. The liquid injection port 120a has a length L11 in the Y direction. The liquid injection port 120c has a length L12 in the Y direction. The liquid injection port 120e has a length L13 in the Y direction. The length L13 is larger than each of the length L11 and the length L12. Note that the length L11 is equal to the length L12. The seal member 30 is disposed (welded) on the liquid injection member 120 so as to seal each of the liquid injection port 120a, the liquid injection port 120c, and the liquid injection port 120e. Note that the liquid injection port 120a and the liquid injection port 120c are examples of the "first liquid injection port" and the "second liquid injection port" of the present disclosure, respectively. The liquid injection port 120e is an example of the "third liquid injection port" of the present disclosure.

[0044] In the above embodiment, an example in which one sealing member 30 seals three liquid injection ports (20a, 20c, 20e) has been shown, but the present disclosure is not limited thereto. One sealing member may seal four or more liquid injection ports arranged side by side.

[0045] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the description of the above embodiments but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0046] 10a battery cell, Z direction (stacking direction), 20a, 120a liquid injection port (first liquid injection port), 20c, 120c liquid injection port (second liquid injection port), 20e, 120e liquid injection port (third liquid injection port), 30 sealing member, 100, 200 power storage module.

Claims

【Claim 1】 a plurality of battery cells stacked in a stacking direction; a plurality of liquid injection ports connected to different battery cells among the plurality of battery cells and arranged side by side in the stacking direction; a sealing member for sealing the plurality of liquid injection ports; and each of the plurality of liquid injection ports protrudes from the connected battery cell in a direction intersecting the stacking direction; the sealing member is welded to each of at least three liquid injection ports adjacent to each other in the stacking direction among the plurality of liquid injection ports to seal each of the at least three liquid injection ports; the at least three liquid injection ports include a first liquid injection port, a second liquid injection port, and at least one third liquid injection port; the first liquid injection port is arranged on one side most in the stacking direction among the at least three liquid injection ports; the second liquid injection port is arranged on the other side most in the stacking direction among the at least three liquid injection ports; the at least one third liquid injection port is arranged between the first liquid injection port and the second liquid injection port in the stacking direction; a power storage module in which the melting amount of the at least one third liquid injection port due to welding with the sealing member is larger than the melting amount of each of the first liquid injection port and the second liquid injection port due to welding with the sealing member.

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