Power storage module

Abstract

To provide a power storage module in which the permeation of an electrolyte solution injected from a liquid injection hole into a lamination electrode body is increased while the insulation between the lamination electrode body and an accommodation body that accommodates the lamination electrode body is secured.SOLUTION: In a lamination electrode body of a power storage module, a plurality of electrodes are stacked in a first direction and extend in a second direction that is perpendicular to the first direction. The lamination electrode body includes a peripheral surface that extends in the second direction and faces an accommodation body. The power storage module includes an insulating sheet part provided between the peripheral surface and the accommodation body and covering the peripheral surface. The insulating sheet part includes first and second insulating sheets that extend in the second direction and cover a part of the peripheral surface. The first and second insulating sheets overlap partially in a peripheral direction of the lamination electrode body. An overlap region where the first and second insulating sheets overlap uses the second direction as a longitudinal direction. The first and second insulating sheets are welded together at a plurality of places apart from each other in the second direction out of the overlap region.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage module. [Background technology]

[0002] Conventionally, energy storage modules equipped with a laminated electrode assembly have been known. JP 2022-79186 A (Patent Document 1) discloses a prismatic secondary battery as such an energy storage module. The prismatic secondary battery includes an exterior body including an opening and a sidewall defining the opening, a sealing plate that seals the opening, an electrode assembly (laminated electrode assembly) housed in the exterior body, a current interruption mechanism provided between the sealing plate and the electrode assembly, and an insulating sheet disposed between the exterior body and the electrode assembly, the insulating sheet having a folded portion on the surface of the electrode assembly facing the current interruption mechanism.

[0003] Specifically, in the prismatic secondary battery, the electrode assembly is wrapped in a box- or bag-shaped insulating sheet and housed in an exterior body that constitutes a battery case, and the sealing plate is provided with an electrolyte injection hole for injecting electrolyte into the battery case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-79186 Summary of the Invention [Problem to be solved by the invention]

[0005] In a storage module such as that described in Patent Document 1, an insulating sheet is placed between the stacked electrode body and a housing (battery case) that houses the stacked electrode body, which may make it difficult for the electrolyte injected through the injection hole to penetrate into the stacked electrode body.

[0006] The present disclosure provides an energy storage module that improves the impregnation of the stacked electrode body with an electrolyte solution injected through an injection hole, while ensuring insulation between the stacked electrode body and a housing that houses the stacked electrode body. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, the energy storage module includes a stacked electrode assembly impregnated with an electrolyte solution and a housing that houses the stacked electrode assembly. The stacked electrode assembly has a plurality of electrodes stacked in a first direction and extending in a second direction perpendicular to the first direction. The stacked electrode assembly has a peripheral surface that extends in the second direction and faces the housing. The energy storage module further includes an insulating sheet portion that is provided between the peripheral surface and the housing and covers the peripheral surface. The insulating sheet portion includes a first insulating sheet and a second insulating sheet that each extend in the second direction and each cover a portion of the peripheral surface. The first insulating sheet and the second insulating sheet partially overlap in the circumferential direction of the stacked electrode assembly. The overlapping region where the first insulating sheet and the second insulating sheet overlap has the second direction as its longitudinal direction. The first insulating sheet and the second insulating sheet are welded to each other at multiple locations in the overlapping region that are spaced apart from each other in the second direction.

[0008] According to the above configuration, the injected electrolyte can be supplied to the stacked electrode body through the gap between the first insulating sheet and the second insulating sheet in the overlapping region where the first insulating sheet and the second insulating sheet are not welded. Therefore, the electricity storage module can improve the impregnation of the stacked electrode body with the electrolyte injected from the outside of the electricity storage module into the interior of the electricity storage module while ensuring insulation between the container and the stacked electrode body.

[0009] Preferably, there are two overlapping regions spaced apart in the circumferential direction, and in each overlapping region, the first insulating sheet and the second insulating sheet are welded to each other at a plurality of locations spaced apart from each other in the second direction.

[0010] According to the above configuration, the impregnation of the electrolyte into the laminated electrode body can be improved compared to a configuration in which one of the two overlapping regions is completely welded in the second direction.

[0011] Preferably, the container has an end face on the second direction side. A liquid injection hole is formed in the end face to inject the electrolyte into the energy storage module. The peripheral surface has first and second main surfaces on the first direction side and first and second side surfaces on the third direction side perpendicular to the first and second directions. The first and second side surfaces are respectively continuous with the first and second main surfaces. One of the two overlapping regions covers at least a portion of the first side surface in the first direction, and the other of the two overlapping regions covers at least a portion of the second side surface in the first direction.

[0012] According to the above configuration, since the electrodes are stacked in the first direction in the stacked electrode body, when the electrolyte is poured in the second direction through the injection hole by gravity, the electrolyte flows more easily toward the first and second side surfaces than toward the first and second main surfaces. In particular, since the overlapping regions create a step, the electrolyte flows more easily toward the first and second side surfaces. Furthermore, in the two overlapping regions, there are areas where the first insulating sheet and the second insulating sheet are not welded. Therefore, the energy storage module can improve the impregnation of the electrolyte into the stacked electrode body.

[0013] Preferably, the length of the container and the electrode in a third direction perpendicular to the first and second directions is longer than the length of the container and the electrode in the first direction. The length of the container and the electrode in the second direction is longer than the length of the container and the electrode in the third direction. The container has an end face on the second direction side. Terminals for external connection are formed on the end face. The terminals are electrically connected to the stacked electrode body.

[0014] According to the above configuration, the length of the energy storage module in the second direction is the longest among the lengths in the first, second, and third directions. Generally, energy storage modules with this shape tend to have poor injectability in the second direction, which is the longitudinal direction. However, according to the energy storage module with the above configuration, the electrolyte can be supplied to the stacked electrode body through the gap between the first insulating sheet and the second insulating sheet, as described above, and therefore the injectability in the second direction can be ensured. Therefore, according to this energy storage module, it is possible to improve the impregnation of the injected electrolyte into the stacked electrode body. [Effects of the Invention]

[0015] According to the present disclosure, it is possible to improve the impregnation of the laminated electrode body with the electrolyte injected through the injection hole while ensuring insulation between the laminated electrode body and the container that houses the laminated electrode body. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a perspective view of the storage module. [Figure 2] 2 is a diagram showing a stacked electrode body included in the electricity storage module of FIG. 1. FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 4 is a diagram in which the laminated electrode body and the insulating sheet portion are extracted from FIG. [Figure 5] 5 is a view of the insulating sheet portion of FIG. 4 as viewed in the direction of arrow V. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0018] FIG. 1 is a perspective view of an energy storage module according to the present embodiment. FIG. 2 is a diagram showing a laminated electrode body included in the energy storage module of FIG. 1. As shown in FIGS. 1 and 2, the energy storage module 1 has a blade shape. The energy storage module 1 includes a laminated electrode body 100 and a housing body 2 that houses the laminated electrode body 100. For ease of explanation, the energy storage module 1 will be described below using as an example a case in which the energy storage module 1 is oriented such that the D3 direction shown in FIGS. 1 and 2 is vertical (more specifically, the direction of D31, which will be described later, faces vertically upward) except during injection of an electrolyte solution, which will be described later.

[0019] In this example, the energy storage module 1 is a lithium iron phosphate (LFP) battery. However, the energy storage module 1 is not limited to this, and may be a ternary (NMC) battery. The energy storage module 1 is mounted, for example, on an electric vehicle that runs on driving force obtained from electric energy. More specifically, a battery pack including a plurality of energy storage modules 1 arranged in a predetermined direction is mounted on the electric vehicle. The battery pack is attached to the body of the electric vehicle. The battery pack forms part of the body. The battery pack serves as a structural component of the body.

[0020] As shown in FIG. 1 , the housing 2 has a substantially rectangular parallelepiped shape. In this example, the housing 2 is a metal housing. The housing 2 has first to sixth surfaces 21 to 26. The first surface 21, the second surface 22, the third surface 23, and the fourth surface 24 are continuous in this order. The first surface 21, the second surface 22, the third surface 23, and the fourth surface 24 form the outer peripheral surface of the housing 2.

[0021] The fifth surface 25 and the sixth surface 26 are end surfaces of the housing body 2. The first surface 21 is the top surface, the second surface 22 is the bottom surface, and the third surface 23 and the fourth surface 24 are side surfaces. A negative electrode side external connection terminal 27 is provided on the fifth surface 25. A positive electrode side external connection terminal (not shown) is provided on the sixth surface 26.

[0022] The D1 direction is the width direction of the energy storage module 1. As shown in FIG. 2, the laminated electrode body 100 has multiple electrodes stacked in the D1 direction (stacking direction). More specifically, in the laminated electrode body 100, a negative electrode 110 and a positive electrode 120 are stacked in the D1 direction with a separator 130 interposed between them. The laminated electrode body 100 further includes a tab 150 connected to the negative electrode side external connection terminal 27, and a tab 160 connected to the positive electrode side external connection terminal. In this way, the laminated electrode body 100 is electrically connected to the negative electrode side external connection terminal 27 and the positive electrode side external connection terminal. The tab 150 is made of a copper foil. The tab 160 is made of an aluminum foil.

[0023] As shown in FIG. 1, the energy storage module 1 and the housing body 2 extend in the D2 direction. As shown in FIG. 2, the stacked electrode body 100 extends in the D2 direction. The D2 direction is perpendicular to the D1 direction. The D2 direction is the longitudinal direction of the energy storage module 1, the housing body 2, and the stacked electrode body 100. The D3 direction is perpendicular to the D1 and D2 directions. The D3 direction is the height direction of the energy storage module 1.

[0024] The D1 direction is the short-side direction of each of the first surface 21, the second surface 22, the fifth surface 25, and the sixth surface 26. The D2 direction is the long-side direction of the first to fourth surfaces 21 to 24. The D3 direction is the short-side direction of the third and fourth surfaces 23 and 24, and the long-side direction of the fifth and sixth surfaces 25 and 26.

[0025] A liquid inlet 2h for injecting the electrolyte into the container 2 is formed on the fifth surface 25. The liquid inlet 2h is formed closer to the first surface 21 than the second surface 22 of the container 2. The liquid inlet 2h is formed closer to the first surface 21 than the external connection terminal 27. In the state shown in FIG. 1, the liquid inlet 2h is blocked because the electrolyte has already been injected into the container 2. The liquid inlet 2h may be temporarily blocked by inserting a removable plug into the liquid inlet 2h. Alternatively, the liquid inlet 2h may be blocked with resin or metal, so that the electrolyte cannot be reinjected unless a through-hole is opened.

[0026] When injecting the electrolyte solution through the injection hole 2h during manufacturing of the electricity storage module 1, the attitude of the electricity storage module 1 is maintained so that the D2 direction is substantially vertical and the fifth surface 25 is higher than the sixth surface 26. The electrolyte solution flows from the fifth surface 25 side to the sixth surface 26 side due to its own weight. Note that the electrolyte solution has a certain degree of viscosity, and therefore falls within the container 2 at a relatively slow speed. This allows the stacked electrode body 100 to be impregnated with the electrolyte solution.

[0027] In this example, the liquid inlet 2h is formed closer to the first surface 21 than the external connection terminal 27, but is not limited to this. The liquid inlet 2h may be formed closer to the second surface 22 than the external connection terminal 27. The liquid inlet 2h may be formed closer to the third surface 23 than the external connection terminal 27. The liquid inlet 2h may be formed closer to the fourth surface 24 than the external connection terminal 27.

[0028] Furthermore, in this example, the configuration in which the liquid inlet 2h is formed on the fifth surface 25 has been described as an example, but the present invention is not limited to this. For example, the liquid inlet 2h may be formed on the sixth surface 26. The liquid inlet 2h may be formed on the first surface 21 or the second surface 22. When the liquid inlet 2h is formed on the first surface 21 or the second surface 22, from the viewpoint of liquid inlet performance, it is preferable that the liquid inlet 2h be formed closer to the end portion (the fifth surface 25 side or the sixth surface 26 side) than to the center in the longitudinal direction of the container 2. The liquid inlet 2h may be formed on the third surface 23 or the fourth surface 24. The position in which the liquid inlet 2h is formed is not particularly limited.

[0029] As described above, the energy storage module 1 has a blade shape. Therefore, the housing 2 also has a blade shape. The stacked electrode assembly 100 housed in the housing 2 also has a blade shape. Therefore, the length in the D3 direction of the housing 2, the negative electrode 110, and the positive electrode 120 is longer than the length in the D1 direction of the housing 2, the negative electrode 110, and the positive electrode 120. Furthermore, the length in the D2 direction of the housing 2, the negative electrode 110, and the positive electrode 120 is longer than the length in the D3 direction of the housing 2, the negative electrode 110, and the positive electrode 120.

[0030] As an example, the length of the housing body 2 in the D3 direction is 6 to 7 times the length of the housing body 2 in the D1 direction. As an example, the length of the housing body 2 in the D2 direction is 10 to 11 times the length of the housing body 2 in the D3 direction. However, the ratio between the length of the housing body 2 in the D1 direction, the length of the housing body 2 in the D2 direction, and the length of the housing body 2 in the D3 direction is not limited to this.

[0031] Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. As shown in Fig. 3, the energy storage module 1 further includes, in addition to the housing 2 and the stacked electrode assembly 100, plate-like members 201 and 202, tape materials 301 and 302, and an insulating sheet unit 500. The insulating sheet unit 500 includes a first insulating sheet 501 and a second insulating sheet 502.

[0032] The plate-shaped members 201 and 202, the tape materials 301 and 302, and the insulating sheet portion 500 are housed in the housing 2, similar to the laminated electrode body 100. The plate-shaped members 201 and 202, the tape materials 301 and 302, and the insulating sheet portion 500 are disposed between the laminated electrode body 100 and the housing 2 (in the gap).

[0033] The plate-shaped members 201 and 202 extend in the D2 direction. The plate-shaped members 201 and 202 are arranged in the housing 2 so that the D3 direction is the thickness direction of the plate-shaped member 201. In this example, the plate-shaped member 202 has a shape symmetrical to the plate-shaped member 201 with respect to the stacked electrode body 100. However, the present invention is not limited to this.

[0034] A plurality of through holes extending in the D3 direction are formed in the plate-shaped members 201 and 202. A plurality of through holes are formed side by side in the D2 direction in the plate-shaped members 201 and 202. Note that the energy storage module 1 does not necessarily have to include the plate-shaped members 201 and 202.

[0035] The plate-shaped members 201 and 202 are insulators. In this example, the plate-shaped members 201 and 202 are made of resin. In this example, the plate-shaped members 201 and 202 are made of an insulating material from the viewpoint of preventing a short circuit between the positive electrode 120 and the negative electrode 110 in the laminated electrode body 100. Note that, if a sufficient insulation distance is ensured between the plate-shaped members 201 and 202 and the laminated electrode body 100, the plate-shaped members 201 and 202 do not necessarily need to be insulators.

[0036] For example, polypropylene is used as the material for forming the plate-like members 201 and 202. However, without being limited to this, polyethylene, polyphenylene sulfide, polyether ether ketone, PET (polyethylene terephthalate), or the like may also be used.

[0037] The plate-shaped member 201 is placed on the laminated electrode body 100. More specifically, the plate-shaped member 201 is placed directly above the laminated electrode body 100. The plate-shaped member 201 is placed on the first surface 21 side of the housing 2. The plate-shaped member 201 is placed in the direction D31 of the D3 direction with respect to the laminated electrode body 100. As described above, the direction D31 is vertically upward.

[0038] The plate-shaped member 202 is disposed below the laminated electrode body 100. More specifically, the plate-shaped member 202 is disposed directly below the laminated electrode body 100. The plate-shaped member 202 is installed on the second surface 22 side of the housing body 2. The plate-shaped member 202 is installed in a direction D32 of the D3 direction relative to the laminated electrode body 100. The direction D32 is vertically downward.

[0039] The plate-shaped member 201 is fixed to the laminated electrode body 100 by a tape material 301. The tape material 301 extends in the D2 direction. The tape material 301 covers all or part of the first surface 211 of the plate-shaped member 201. The tape material 301 covers all or part of the third and fourth surfaces 213, 214 of the plate-shaped member 201. The tape material 301 covers a portion of the laminated electrode body 100.

[0040] The plate-shaped member 202 is fixed to the laminated electrode body 100 by a tape material 302. The tape material 302 extends in the D2 direction. The tape material 302 covers all or part of the first surface 221 of the plate-shaped member 202. The tape material 302 covers all or part of the third and fourth surfaces 223, 224 of the plate-shaped member 202. The tape material 302 covers a portion of the laminated electrode body 100.

[0041] The laminated electrode body 100 has a peripheral surface 180. The peripheral surface 180 extends in the D2 direction. Fig. 3 shows a cross section of the peripheral surface 180. The cross section of the peripheral surface 180 has a rectangular shape. Each surface that constitutes the peripheral surface 180 will be described later.

[0042] The insulating sheet portion 500 is provided between the peripheral surface 180 of the laminated electrode body 100 and the housing 2, and covers the peripheral surface 180. The insulating sheet portion 500 insulates the laminated electrode body 100 from the housing 2. The insulating sheet portion 500 covers the laminated electrode body 100 so that the laminated electrode body 100 does not come into contact with the housing 2. The insulating sheet portion 500 is provided between the laminated electrode body 100 and the housing 2 (more specifically, the inner surface of the housing) to prevent a short circuit of the laminated electrode body 100.

[0043] More specifically, the first insulating sheet 501 partially covers the plate-shaped members 201 and 202. The first insulating sheet 501 covers the plate-shaped member 201 via the tape material 301. Similarly, the first insulating sheet 501 covers the plate-shaped member 202 via the tape material 302.

[0044] More specifically, the second insulating sheet 502 partially covers the plate-shaped members 201 and 202. The second insulating sheet 502 covers the plate-shaped member 201 via the tape material 301. Similarly, the second insulating sheet 502 covers the plate-shaped member 202 via the tape material 302.

[0045] The ends of the first insulating sheet 501 and the second insulating sheet 502 are welded together. With the plate-shaped members 201 and 202 fixed to the laminated electrode body 100 by the tape materials 301 and 302, the first and second insulating sheets 501 and 502 are wrapped around the tape materials 301 and 302, the plate-shaped members 201 and 202, and the laminated electrode body 100. Thereafter, the end of the first insulating sheet 501 and the end of the second insulating sheet 502 are welded together to obtain the insulating sheet part 500 shown in FIG. 3.

[0046] For example, polypropylene is used as the material for forming the first and second insulating sheets 501, 502. However, the material is not limited to this, and polyethylene, polyphenylene sulfide, polyether ether ketone, nylon, or PET (polyethylene terephthalate) may also be used.

[0047] Fig. 4 is a diagram illustrating the laminated electrode body 100 and the insulating sheet portion 500 extracted from Fig. 3. As shown in Fig. 4, the peripheral surface 180 of the laminated electrode body 100 has first and second side surfaces 181, 182 on the D3 direction side and first and second main surfaces 183, 184 on the D1 direction side. That is, the peripheral surface 180 has the first and second side surfaces 181, 182 whose normal direction is the D3 direction, and the first and second main surfaces 183, 184 whose normal direction is the D1 direction.

[0048] The first side surface 181 is continuous with the first and second main surfaces 183 and 184. The first side surface 181 is the top surface. Similarly, the second side surface 182 is continuous with the first and second main surfaces 183 and 184. The second side surface 182 is the bottom surface.

[0049] As shown in FIGS. 3 and 4, the first side surface 181 is parallel to the first surface 21 of the housing body 2. The second side surface 182 is parallel to the second surface 22. The first side surface 181 is closer to the first surface 21 of the housing body 2 than the second side surface 182. The first main surface 183 is parallel to the third surface 23. The second main surface 184 is parallel to the fourth surface 24. The first main surface 183 is closer to the third surface 23 than the second main surface 184. The length (width) of the first and second side surfaces 181, 182 in the D1 direction is narrower than the length (width) of the first and second main surfaces 183, 184 in the D3 direction.

[0050] The first insulating sheet 501 and the second insulating sheet 502 partially overlap in the circumferential direction of the laminated electrode body 100. The overlapping regions T1 and T2 where the first insulating sheet 501 and the second insulating sheet 502 overlap have the longitudinal direction in the D2 direction. The overlapping regions T1 and T2 extend in the D2 direction. In this way, the two overlapping regions T1 and T2 are located at positions spaced apart in the circumferential direction of the laminated electrode body 100.

[0051] The "circumferential direction" refers to the direction of the circumferential surface 180. In this example, the "circumferential direction" refers to the direction in which the first side surface 181, the second main surface 184, the second side surface 182, and the first main surface 183 are arranged in this order in Fig. 4 (the clockwise direction in Fig. 4).

[0052] In the overlapping region T1, the D31 side end of the first insulating sheet 501 and the D31 side end of the second insulating sheet 502 are welded to each other in an overlapping state. In the overlapping region T2, the D32 side end of the first insulating sheet 501 and the D32 side end of the second insulating sheet 502 are welded to each other in an overlapping state.

[0053] In this example, the overlapping region T1 covers the first side surface 181. The overlapping region T2 covers the second side surface 182. The overlapping region T1 covers a portion of the first side surface 181 in the D1 direction. The overlapping region T2 covers a portion of the second side surface 182 in the D1 direction. This is not limiting, and the overlapping region T1 may cover the entire first side surface 181 in the D1 direction. The overlapping region T2 may cover the entire second side surface 182 in the D1 direction. However, from the viewpoint of the impregnation of the electrolyte solution into the laminated electrode body, it is preferable that the overlapping regions T1 and T2 cover a portion of the first and second side surfaces 181 and 182, respectively, as described above.

[0054] In the overlapping region T1, the second insulating sheet 502 is located closer to D31 than the first insulating sheet 501. In the overlapping region T2, the second insulating sheet 502 is also located closer to D31 than the first insulating sheet 501. However, the order of overlapping is not limited to this.

[0055] Fig. 5 is a view of the insulating sheet part 500 of Fig. 4 as viewed in the direction of arrow V. Fig. 5 is a view of the insulating sheet part 500 in the state of Fig. 4 as viewed from above.

[0056] As shown in Fig. 5, the first insulating sheet 501 and the second insulating sheet 502 are welded to each other at a plurality of locations W that are spaced apart from each other in the direction D2 in the overlapping region T1. Similarly, the first insulating sheet 501 and the second insulating sheet 502 are welded to each other at a plurality of locations W that are spaced apart from each other in the direction D2 in the overlapping region T2 (not shown in Fig. 5). Each location W is thermally welded with a hot iron or the like. Each location W is a welded location.

[0057] In this example, the multiple locations W are spaced apart at equal intervals in the D2 direction. However, this is not limited to this, and the intervals between adjacent locations W do not have to be constant. For example, the closer to the center in the D2 direction, the longer the separation distance between locations W may be.

[0058] <Summary> (1) As described above, the energy storage module 1 includes a laminated electrode assembly 100 impregnated with an electrolyte solution and a housing 2 that houses the laminated electrode assembly 100. The laminated electrode assembly 100 has multiple electrodes (negative electrodes 110 and positive electrodes 120) stacked in the D1 direction and extending in the D2 direction perpendicular to the D1 direction. The laminated electrode assembly 100 extends in the D2 direction and has a peripheral surface 180 that faces the housing 2.

[0059] The energy storage module 1 further includes an insulating sheet portion 500 that is provided between the peripheral surface 180 and the housing 2 and covers the peripheral surface 180. The insulating sheet portion 500 includes a first insulating sheet 501 and a second insulating sheet 502 that each extend in the D2 direction and each cover a portion of the peripheral surface 180.

[0060] The first insulating sheet 501 and the second insulating sheet 502 partially overlap in the circumferential direction of the laminated electrode body 100. The D2 direction is the longitudinal direction of the overlapping regions T1, T2 where the first insulating sheet 501 and the second insulating sheet 502 overlap. The first insulating sheet 501 and the second insulating sheet 502 are welded to each other at multiple locations W in the overlapping regions T1, T2 that are spaced apart from each other in the D2 direction.

[0061] With this configuration, the injected electrolyte solution can be supplied to the stacked electrode body 100 through the gap between the first insulating sheet 501 and the second insulating sheet 502 in the non-welded portions of the overlapping regions T1, T2 of the first insulating sheet 501 and the second insulating sheet 502. Therefore, with the electricity storage module 1, the insulation between the container 2 and the stacked electrode body 100 can be ensured, while the impregnation of the stacked electrode body 100 with the electrolyte solution injected from the outside of the electricity storage module 1 into the inside of the electricity storage module 1 can be improved.

[0062] (2) Two overlapping regions T1 and T2 are present at positions spaced apart in the circumferential direction. In each overlapping region T1 and T2, the first insulating sheet 501 and the second insulating sheet 502 are welded to each other at multiple locations W that are spaced apart from each other in the D2 direction.

[0063] With this configuration, the impregnation of the electrolyte into the laminated electrode body 100 can be improved compared to a configuration in which one of the two overlapping regions T1, T2 is completely welded across the D2 direction.

[0064] (3) The housing body 2 has a fifth surface 25 on the D2 direction side. A liquid injection hole 2h is formed in the fifth surface 25, through which an electrolyte solution is injected into the electricity storage module 1. The peripheral surface 180 has first and second main surfaces 183, 184 on the D1 direction side and first and second side surfaces 181, 182 on the D3 direction side. The first and second side surfaces 181, 182 are continuous with the first and second main surfaces 183, 184, respectively. One of the two overlapping regions T1, T2 (in this example, overlapping region T1) covers at least a portion of the first side surface 181 in the first direction, and the other of the two overlapping regions T1, T2 (overlapping region T2) covers at least a portion of the second side surface 182 in the first direction.

[0065] With this configuration, since multiple electrodes are stacked in the D1 direction in the laminated electrode body 100, when the electrolyte is poured by gravity in the D2 direction through the liquid inlet 2h, the electrolyte flows more easily toward the first and second side faces 181 and 182 than toward the first and second main faces 183 and 184. In particular, since the overlapping regions T1 and T2 create steps, the electrolyte flows more easily toward the first and second side faces 181 and 182. Furthermore, in each of the overlapping regions T1 and T2, there are portions where the first insulating sheet 501 and the second insulating sheet 502 are not welded together. Therefore, the energy storage module 1 can improve the impregnation of the electrolyte into the laminated electrode body 100.

[0066] (4) The length in the D3 direction of the container 2 and the electrodes (negative electrode 110 and positive electrode 120) is longer than the length in the D1 direction of the container 2 and the electrodes. The length in the D2 direction of the container 2 and the electrodes is longer than the length in the D3 direction of the container 2 and the electrodes. As shown in FIG. 1 , the container 2 has a fifth surface 25 on the D2 direction side. An external connection terminal 27 is formed on the fifth surface 25. The external connection terminal 27 is electrically connected to the laminated electrode body 100.

[0067] With this configuration, the length of the energy storage module 1 in the D2 direction is the longest among the lengths in the D1 direction, the D2 direction, and the D3 direction. Generally, energy storage modules with this shape tend to have poor injectability in the longitudinal direction, that is, the D2 direction. However, with the energy storage module 1, as described above, the electrolyte can be supplied to the stacked electrode body 100 through the gap between the first insulating sheet 501 and the second insulating sheet 502. This ensures injectability in the D2 direction. Therefore, with the energy storage module 1, even if the length in the D2 direction is the longest among the lengths in the D1 direction, the D2 direction, and the D3 direction, it is possible to improve the impregnation of the injected electrolyte into the stacked electrode body 100.

[0068] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present disclosure is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0069] 1 storage module, 2 container, 2h liquid hole, 21, 211, 221 first surface, 22, 212, 222 second surface, 23, 213, 223 third surface, 24, 214, 224 fourth surface, 25 fifth surface, 26 sixth surface, 27 external connection terminal, 100 laminated electrode body, 110 negative electrode, 120 positive electrode, 130 separator, 150, 160 tab, 180 peripheral surface, 181 first side surface, 182 second side surface, 183 first main surface, 184 second main surface, 201, 202 plate-shaped member, 301, 302 tape material, 500 insulating sheet portion, 501 first insulating sheet, 502 second insulating sheet, T1, T2 overlapping region.

Claims

1. A power storage module, a laminated electrode body impregnated with an electrolyte; a housing that houses the stacked electrode body, The laminated electrode body is A plurality of electrodes are stacked in a first direction and extend in a second direction perpendicular to the first direction; a peripheral surface extending in the second direction and facing the container; the energy storage module further includes an insulating sheet portion provided between the peripheral surface and the housing and covering the peripheral surface; the insulating sheet portion includes a first insulating sheet and a second insulating sheet, each of which extends in the second direction and covers a portion of the circumferential surface; the first insulating sheet and the second insulating sheet are partially overlapped in the circumferential direction of the laminated electrode body, and the overlapping region where the first insulating sheet and the second insulating sheet overlap has the second direction as its longitudinal direction; the first insulating sheet and the second insulating sheet are welded to each other at a plurality of locations in the overlapping region that are spaced apart from each other in the second direction.

2. two overlapping regions are present at positions spaced apart in the circumferential direction, The energy storage module according to claim 1 , wherein in each of the overlapping regions, the first insulating sheet and the second insulating sheet are welded to each other at a plurality of locations spaced apart from each other in the second direction.

3. the container has an end surface on the second direction side, a liquid injection hole for injecting the electrolyte into the electricity storage module is formed in the end surface; the peripheral surface has first and second main surfaces on the first direction side and first and second side surfaces on the third direction side perpendicular to the first and second directions, the first and second side surfaces are continuous with the first and second main surfaces, respectively; 3. The energy storage module according to claim 2, wherein one of the two overlapping regions covers at least a portion of the first side surface in the first direction, and the other of the two overlapping regions covers at least a portion of the second side surface in the first direction.

4. a length of the container and the electrode in a third direction perpendicular to the first direction and the second direction is longer than a length of the container and the electrode in the first direction; a length of the housing and the electrode in the second direction is longer than a length of the housing and the electrode in the third direction; the container has an end surface on the second direction side, A terminal for external connection is formed on the end surface, The energy storage module according to claim 1 , wherein the terminal is electrically connected to the laminated electrode body.

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