Lamination electrode body and power storage module

Abstract

To provide a lamination electrode body capable of suppressing the space that does not contribute to charging and discharging while preventing the displacement of each separator.SOLUTION: A lamination electrode body includes a plurality of electrodes and a plurality of separators. The electrodes and the separators are stacked alternately in a first direction. The lamination electrode body extends in a second direction that is perpendicular to the first direction. The lamination electrode body further includes a peripheral surface extending in the second direction. The length of each separator in a third direction perpendicular to the first and second directions is longer than the length of each electrode in the third direction. The peripheral surface includes first and second main surfaces on the first direction side and first and second side surfaces on the third direction side, which are continuous to the first and second main surfaces, respectively. In at least one of the first side surface and the second side surface, the separators are welded along the length of the lamination electrode body in the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a stacked electrode assembly and an electricity storage module. [Background technology]

[0002] Electricity storage modules have been known for some time. JP 2012-209054 A (Patent Document 1) discloses an electrode stack (laminated electrode body) for a stacked battery, which is an electricity storage module. The electrode stack is formed by stacking a plurality of electrodes, each disposed between separators. The electrode stack has separator joints, which join the stacked separators together, provided at a plurality of positions around the electrodes. The plurality of positions are positions that restrict movement of the electrodes in a direction intersecting the stacking direction of the electrode stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-209054 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the separator joint position in the stacking direction of the electrode stack is the same as that of the separator arranged at the bottom or middle of the stacking direction. A portion of each separator, except for the separator arranged at the bottom or middle, extends from the outer edge of each stacked positive electrode and negative electrode toward the separator joint. Therefore, in Patent Document 1, a large space that does not contribute to charge and discharge must be provided from the outer edge of each stacked positive electrode and negative electrode to the separator joint.

[0005] The present disclosure provides a stacked electrode assembly that can prevent misalignment of separators while minimizing space that does not contribute to charge and discharge. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a laminated electrode assembly includes a plurality of electrodes and a plurality of separators. The electrodes and separators are alternately stacked in a first direction. The laminated electrode assembly extends in a second direction perpendicular to the first direction. The laminated electrode assembly further includes a peripheral surface extending in the second direction. The length of each separator in a third direction perpendicular to the first and second directions is longer than the length of each electrode in the third direction. 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, each of which is continuous with the first and second main surfaces. Each separator is welded to at least one of the first side surface and the second side surface along the length of the laminated electrode assembly in the first direction.

[0007] According to the above configuration, each separator is welded to at least one of the first side surface and the second side surface along the length of the stacked electrode body in the first direction. Therefore, movement of each separator in the third direction within the stacked electrode body is restricted. Therefore, it is possible to prevent displacement of each separator. Furthermore, according to the above configuration, it is possible to reduce the amount of each separator protruding from the outer edge of each electrode. Therefore, it is possible to reduce the space that does not contribute to charging and discharging.

[0008] Preferably, the separators are welded to each other at each of a plurality of locations spaced apart in the second direction over the length of the stacked electrode assembly in the first direction.

[0009] According to the above configuration, the electrolyte can be impregnated into the inside of the laminated electrode body from the unwelded portion of the second side surface, making it easier to impregnate the inside of the laminated electrode body with the electrolyte than when the entire second side surface is welded.

[0010] According to another aspect of the present disclosure, an energy storage module includes a stacked electrode assembly and a housing that houses the stacked electrode assembly. The housing has a liquid inlet formed therein for injecting an electrolyte into the housing. The liquid inlet is formed at an end of the housing on the second direction side and is closer to the first side surface than the second side surface. Of the first side surface and the second side surface, each separator is welded only to the second side surface.

[0011] According to the above configuration, the electrolyte solution passes more easily through the first side surface than through the second side surface. Although the welded portion prevents the electrolyte solution from flowing into the stacked electrode body, because the welded portion is only on the second side surface, the electrolyte solution is more easily impregnated into the stacked electrode body than when the welded portion is on the first side surface. Therefore, according to the energy storage module, the electrolyte solution can be more efficiently impregnated into the stacked electrode body when the electrolyte solution is injected into the container than when the injection hole is formed closer to the second side surface than to the first side surface.

[0012] Preferably, the separators are welded to each other at a plurality of locations spaced apart in the second direction over the length of the stacked electrode body in the first direction, with the lengths of the locations in the second direction becoming shorter as the locations become farther from the liquid inlet.

[0013] When the electrolyte solution is injected into the container, most of the electrolyte solution does not immediately impregnate the laminated electrode body, but instead passes around the laminated electrode body and moves toward the opposite side of the inlet. The electrolyte solution then moves through the laminated electrode body 100 from the opposite side of the inlet toward the inlet due to capillary action. This action allows the electrolyte solution to be supplied throughout the entire laminated electrode body. Additionally, as the amount of electrolyte solution injected increases over time, the electrolyte solution can be supplied into the laminated electrode body from the periphery of the laminated electrode body. As described above, the length in the second direction is shorter at locations farther from the through-holes. Therefore, the electrolyte solution can be efficiently impregnated into the interior of the laminated electrode body 100C from the portion of the second side surface of the laminated electrode body farther from the through-holes. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to prevent the positional deviation of each separator while suppressing the space that does not contribute to charge and discharge. [Brief explanation of the drawings]

[0015] [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] 4 is a view of the laminated electrode body of FIG. 3 viewed in a predetermined direction. [Figure 5] FIG. 10 is a diagram showing a first modified example of a laminated electrode body. [Figure 6] FIG. 10 is a diagram showing a second modified example of the laminated electrode body. [Figure 7] FIG. 10 is a diagram showing a third modified example of the laminated electrode body. [Figure 8] FIG. 10 is a diagram showing a fourth modified example of the laminated electrode body. [Figure 9] FIG. 10 is a diagram showing a fifth modified example of the laminated electrode body. [Figure 10] FIG. 10 is a diagram showing a sixth modified example of the laminated electrode body. [Figure 11] FIG. 10 is a cross-sectional view of another power storage module. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each embodiment 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.

[0017] [Embodiment 1] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] As shown in FIG. 2, the laminated electrode body 100 has multiple electrodes (negative electrodes 110, positive electrodes 120) and multiple separators 130. In the laminated electrode body 100, multiple electrodes are stacked in the D1 direction (stacking direction). More specifically, in the laminated electrode body 100, the negative electrodes 110 and the positive electrodes 120 are stacked alternately in the D1 direction with the separators 130 interposed therebetween. That is, in the laminated electrode body 100, the negative electrodes 110, the separators 130, the positive electrodes 120, and the separators 130 are arranged repeatedly in this order. The D1 direction is the width direction of the energy storage module 1. The positive electrodes 120 have the same size. The negative electrodes 110 have the same size. The separators 130 have the same size.

[0022] The length of each separator 130 in the D3 direction is longer than the length of each positive electrode 120 in the D3 direction. Similarly, the length of each separator 130 in the D3 direction is longer than the length of each negative electrode 110 in the D3 direction.

[0023] 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. The tab 150 is made of a copper foil, and the tab 160 is made of an aluminum foil.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. Fig. 3 is a diagram showing a cross section of the energy storage module 1. As shown in Fig. 3, the energy storage module 1 further includes plate-like members 201 and 202, tape materials 301 and 302, and an insulating sheet 500 in addition to the housing 2 and the stacked electrode body 100.

[0028] The plate-shaped members 201 and 202, the tape materials 301 and 302, and the insulating sheet 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 500 are disposed between the laminated electrode body 100 and the housing 2 (in the gap).

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The plate-shaped member 201 is fixed to the laminated electrode assembly 100 by a tape material 301. The plate-shaped member 202 is fixed to the laminated electrode assembly 100 by a tape material 302. The tapes 301 and 302 extend in the D2 direction. The tapes 301 and 302 cover a portion of the laminated electrode assembly 100.

[0036] The laminated electrode body 100 has a circumferential surface 180. The circumferential surface 180 extends in the D2 direction. FIG. 3 shows a cross section of the circumferential surface 180. The cross section of the circumferential surface 180 has a rectangular shape. The circumferential surface 180 faces the housing 2. The circumferential surface 180 faces the inner circumferential surface of the housing 2. The circumferential surface 180 faces the housing 2 via a member such as an insulating sheet 500.

[0037] The peripheral surface 180 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.

[0038] 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.

[0039] The first side surface 181 is parallel to the first surface 21 of the housing 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 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 width of the first and second side surfaces 181, 182 in the D1 direction is narrower than the width of the first and second main surfaces 183, 184 in the D3 direction.

[0040] The insulating sheet 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 500 insulates the laminated electrode body 100 from the housing 2. The insulating sheet 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 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.

[0041] More specifically, the insulating sheet 500 covers the plate-shaped members 201 and 202. The insulating sheet 500 covers the plate-shaped member 201 via the tape material 301. Similarly, the insulating sheet 500 covers the plate-shaped member 202 via the tape material 302.

[0042] The insulating sheet 500 has both ends welded together. With the plate-shaped members 201, 202 fixed to the laminated electrode assembly 100 by the tape materials 301, 302, the insulating sheet 500 is wrapped around the tape materials 301, 302, the plate-shaped members 201, 202, and the laminated electrode assembly 100. Then, both ends of the insulating sheet 500 are welded together to obtain the insulating sheet 500 shown in FIG. 3. In the welded region T, the ends of the insulating sheet 500 overlap. The welded region T extends in the D2 direction. The insulating sheet 500 may also be formed by connecting multiple insulating sheets.

[0043] For example, polypropylene is used as the material for insulating sheet 500. However, without being limited to this, polyethylene, polyphenylene sulfide, polyether ether ketone, nylon, or PET (polyethylene terephthalate) may also be used.

[0044] Fig. 4 is a view of the laminated electrode body 100 of Fig. 3 viewed in the direction of arrow B. As shown in Fig. 4, the laminated electrode body 100 has a first side surface 181, a second side surface 182, a first main surface 183, and a second main surface 184, as well as a first end surface 185 and a second end surface 186.

[0045] The first end surface 185 is the surface on the fifth surface 25 side where the negative electrode side external connection terminal 27 (FIG. 1) is provided. The second end surface 186 is the surface on the sixth surface 26 (FIG. 1) side where the positive electrode side external connection terminal is provided.

[0046] Each separator 130 is welded to the second side surface 182 along the length of the laminated electrode body 100 in the D1 direction. With this configuration, movement of each separator 130 in the D3 direction within the laminated electrode body 100 is restricted. Therefore, the laminated electrode body 100 can prevent displacement of each separator 130. Furthermore, the laminated electrode body 100 can reduce the amount of each separator 130 protruding from the outer edges of the negative electrode 110 and the positive electrode 120. Therefore, the laminated electrode body 100 can reduce space that does not contribute to charge and discharge.

[0047] Specifically, the separators 130 are welded to each other at multiple locations spaced apart in the D2 direction along the length of the stacked electrode body 100 in the D1 direction. In this embodiment, the separators 130 are directly welded to each other. In the stacked electrode body 100, there are multiple welded parts U1 formed by welding the separators 130 to each other.

[0048] The length of each welded portion U1 in the D1 direction is the same. The length in the D1 direction is approximately the same as the length of the laminated electrode body 100 in the D1 direction. The length of each welded portion U1 in the D2 direction is the same. In this example, each welded portion U1 is formed evenly in the D2 direction. The distance between adjacent welded portions U1 is the same. Each welded portion U1 is typically formed by contacting each separator 130 with a hot iron.

[0049] Each welded portion U1 covers a part of the positive electrode 120 and a part of the negative electrode 110 in the direction D1 when the laminated electrode body 100 is viewed from the second side surface 182 side. Each welded portion U1 may be in contact with the outer edge of the positive electrode 120 and the outer edge of the negative electrode 110.

[0050] The multiple separators 130 are fixed to one another by the welded portions U1. The relative positions of the separators 130 are fixed on the second side surface 182 side. Therefore, movement of the separators 130 in the direction D3 within the stacked electrode body 100 is restricted. In this way, the energy storage module 1 can prevent misalignment of the separators 130. Furthermore, the welded portions can be made smaller than when the separators 130 are welded to one another over the entire surface of the second side surface 182.

[0051] As described above, the separators 130 are directly welded to each other, so the positions of the separators 130 can be fixed without using any other members. Furthermore, in the energy storage module 1, the welded portions U1 are formed evenly in the D2 direction as described above, so the separators 130 are more effectively prevented from shifting positions than if they were not formed evenly.

[0052] Each positive electrode 120 and each negative electrode 110 is sandwiched between separators 130. This makes it possible to restrict movement of each positive electrode 120 and each negative electrode 110 in the D3 direction relative to each separator 130. More specifically, it is also possible to suppress positional deviation of each positive electrode 120 and each negative electrode 110 in the D31 direction relative to each separator 130.

[0053] Furthermore, the energy storage module 1 has the following advantages when the electrolyte is injected into the container 2 through the injection hole 2h (FIG. 1). When the electrolyte is injected through the injection hole 2h during manufacturing of the energy storage module 1, the orientation of the energy 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 weight of the electrolyte causes the electrolyte to flow from the fifth surface 25 side to the sixth surface 26 side. Note that the electrolyte 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.

[0054] In this regard, on the second side surface 182 of the laminated electrode body 100, the separators 130 are not welded to each other between the welded portions U1 as described above. Therefore, when the electrolyte solution falls inside the container 2 or when the fallen electrolyte solution rises up, the electrolyte solution can be impregnated into the interior of the laminated electrode body 100 from the unwelded portions of the second side surface 182 (hereinafter also referred to as "unwelded portions"). Note that on the first side surface 181, since there are no welded portions U1, when the electrolyte solution falls inside the container 2, the electrolyte solution can be impregnated into the interior of the laminated electrode body 100 from the entire first side surface 181.

[0055] In this way, by welding the separators 130 to each other at multiple locations on the second side surface 182 along the length of the laminated electrode body 100 in the D1 direction, it is easier to impregnate the interior of the laminated electrode body 100 with the electrolyte than if the entire second side surface 182 were welded.

[0056] As described above, the liquid inlet 2h is formed closer to the first surface 21 than to the second surface 22 of the container 2. In the D3 direction, the liquid inlet 2h is located closer to the first side surface 181 than to the second side surface 182 of the stacked electrode body 100. In other words, the first side surface 181, on which the welded portion U1 is not formed, is located closer to the liquid inlet 2h than the second surface 22, on which the welded portion U1 is formed.

[0057] When the electrolyte is poured in the direction D2 by gravity through the liquid inlet 2h, the liquid inlet 2h is closer to the first side surface 181 than to the second side surface 182, and therefore the electrolyte is more likely to pass through the first side surface 181 side than the second side surface 182. The welded portion U1 prevents the electrolyte from flowing into the laminated electrode body 100, but because the welded portion U1 is only on the second side surface 182 side, the electrolyte is more likely to permeate the laminated electrode body 100 than if it were on the first side surface 181 side.

[0058] Therefore, with this configuration, when the electrolyte solution is injected into the container 2, the electrolyte solution can be more efficiently impregnated into the interior of the laminated electrode body 100 than when the injection hole 2h is formed closer to the second side surface 182 than to the first side surface 181.

[0059] Note that, similar to the second side surface 182, a plurality of welded portions U1 may be formed on the first side surface 181 (FIG. 3). In this case, it is possible to further prevent misalignment of the separators 130 compared to when the separators 130 are welded on the second side surface 182. Furthermore, with this configuration, it is possible to prevent misalignment of the positive electrodes 120 and negative electrodes 110 relative to the separators 130 in the direction D32. Therefore, with this configuration, it is possible to prevent misalignment of the positive electrodes 120 and negative electrodes 110 relative to the separators 130 in the direction D3.

[0060] The present invention is not limited to the above, and the welded portion U1 may be formed only on the first side surface 181 out of the first side surface 181 and the second side surface 182. It is sufficient that each separator 130 is welded to at least one of the first side surface 181 and the second side surface 182 over the length of the laminated electrode body 100 in the D1 direction.

[0061] 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.

[0062] 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.

[0063] <Summary> As described above, the energy storage module 1 includes a stacked electrode assembly 100 impregnated with an electrolyte solution and a housing 2 that houses the stacked electrode assembly 100. As shown in Fig. 2, the stacked electrode assembly 100 has positive electrodes 120, separators 130, and negative electrodes 110 stacked alternately in the direction D1, and extends in the direction D2 perpendicular to the direction D1.

[0064] As shown in Fig. 3, the laminated electrode assembly 100 has a circumferential surface 180 that extends in the D2 direction and faces the housing 2 (more specifically, the inner circumferential surface of the housing). The length of each separator 130 in the D3 direction, which is perpendicular to the D1 and D2 directions, is longer than the length of each positive electrode 120 and each negative electrode 110 in the D3 direction. As shown in Fig. 3, the circumferential 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 that are continuous with the first and second main surfaces 183, 184, respectively.

[0065] 3, the width in the D1 direction of the first and second side surfaces 181, 182 is narrower than the width in the D3 direction of the first and second main surfaces 183, 184. In the example of FIG. 4, each separator 130 is welded to the second side surface 182 over the length of the stacked electrode body 100 in the D1 direction.

[0066] Specifically, as shown in FIG. 4, the separators 130 are welded to each other at each of a plurality of locations spaced apart in the D2 direction over the length of the stacked electrode assembly 100 in the D1 direction.

[0067] More specifically, as shown in Fig. 1, the accommodating body 2 has an inlet 2h formed therein for injecting an electrolyte solution into the electricity storage module 100. As shown in Fig. 1, the inlet 2h is formed at the end of the accommodating body 2 on the D2 direction side, and is closer to the first side surface 181 than to the second side surface 182. As shown in Fig. 4, of the first side surface 181 and the second side surface 182, each separator 130 is welded only to the second side surface 182. However, this is not a limitation, and it is sufficient that each separator 130 is welded to at least one of the first side surface 181 and the second side surface 182 over the length of the stacked electrode body 100 in the D1 direction.

[0068] <Modification> The following describes modified examples of the laminated electrode assembly 100. In particular, modified examples of the positions where the welded portions of the separators 130 are formed will be described.

[0069] (1) First Modification Fig. 5 is a diagram showing a first modified example of the laminated electrode body 100. As shown in Fig. 5, in the laminated electrode body 100A, like the laminated electrode body 100, the separators 130 are welded to each other on the second side surface 182 along the length of the laminated electrode body 100A in the D1 direction. Specifically, the separators 130 are welded to each other at multiple locations spaced apart in the D2 direction along the length of the laminated electrode body 100A in the D1 direction. The separators 130 are directly welded to each other. In the laminated electrode body 100A, there are multiple welded portions U1 formed by welding the separators 130 to each other.

[0070] In the laminated electrode body 100A, the welded portion U1 is biased toward the center in the D2 direction of the second side surface 182. In the laminated electrode body 100A, the welded portion U1 is not present at the end of the second side surface 182 in the D2 direction.

[0071] The laminated electrode body 100A configured in this manner can achieve the same effects as the laminated electrode body 100. Furthermore, the laminated electrode body 100A allows the electrolyte to be impregnated into the laminated electrode body more easily than the laminated electrode body 100. In particular, the laminated electrode body 100A allows the electrolyte to be impregnated from both ends in the D2 direction of the second side surface 182 more easily than the laminated electrode body 100.

[0072] (2) Second Modification FIG. 6 is a diagram showing a second modified example of the laminated electrode body 100. As shown in FIG. 6, in the laminated electrode body 100B, like the laminated electrode body 100, the separators 130 are welded to each other on the second side surface 182 along the length of the laminated electrode body 100B in the D1 direction. Specifically, the separators 130 are welded to each other at multiple locations spaced apart in the D2 direction along the length of the laminated electrode body 100B in the D1 direction. The separators 130 are welded directly to each other. In the laminated electrode body 100B, there are multiple welded portions U1 formed by welding the separators 130 to each other.

[0073] In the laminated electrode body 100B, the welded parts U1 are biased in the D2 direction towards the end of the second side surface 182. In the laminated electrode body 100B, the welded parts U1 are not present in the center in the D2 direction.

[0074] The laminated electrode body 100B configured in this manner can achieve the same effects as the laminated electrode body 100. Furthermore, the laminated electrode body 100B allows the electrolyte to be impregnated into the laminated electrode body more easily than the laminated electrode body 100. In particular, the laminated electrode body 100B allows the electrolyte to be impregnated from the center of the second side surface 182 in the D2 direction more easily than the laminated electrode body 100.

[0075] (3) Third Modification Fig. 7 is a diagram showing a third modified example of the laminated electrode body 100. As shown in Fig. 7, in the laminated electrode body 100C, like the laminated electrode body 100, the separators 130 are welded to each other on the second side surface 182 along the length of the laminated electrode body 100C in the D1 direction. Specifically, the separators 130 are welded to each other at each of a plurality of locations spaced apart in the D2 direction along the length of the laminated electrode body 100C in the D1 direction. The separators 130 are welded to each other directly.

[0076] The stacked electrode body 100C has a plurality of welded portions U2, U3, U4, and U5 formed by welding the separators 130 together. The welded portions U2, U3, U4, and U5 are arranged in this order from the second end face 186 toward the first end face 185.

[0077] The lengths of the welded portions U2, U3, U4, and U5 in the D1 direction are the same as the length of the welded portion U1 in the D1 direction. The lengths (widths) of the welded portions U2, U3, U4, and U5 in the D2 direction are shorter in this order. The welded portions U2, U3, U4, and U5 that are farther from the fifth surface 25 (the surface on the first end surface 185 side) of the container 2 have shorter lengths (widths) in the D2 direction. In other words, the welded portions U2, U3, U4, and U5 that are farther from the liquid inlet 2h have shorter lengths (widths) in the D2 direction.

[0078] When the electrolyte solution is poured into the container 2, most of the electrolyte solution does not immediately soak into the laminated electrode body 100C, but first passes around the laminated electrode body 100C and moves (falls) from the first end face 185 side to the side opposite the liquid inlet hole 2h (the second end face 186 side). Then, due to capillary action, the electrolyte solution moves (rises) within the laminated electrode body 100C from the side opposite the liquid inlet hole 2h (the second end face 186 side) toward the first end face 185 side (the liquid inlet hole 2h side). This action allows the electrolyte solution to be supplied throughout the entire interior of the laminated electrode body 100C.

[0079] In addition, if the amount of electrolyte injected increases over time, the electrolyte can be supplied from the periphery into the laminated electrode body 100C. At this time, since the welded portion farther from the liquid inlet 2h has a shorter length (width) in the D2 direction, the electrolyte can be efficiently impregnated into the laminated electrode body 100C from the portion of the second side surface 182 of the laminated electrode body 100C farther from the liquid inlet 2h (more specifically, the non-welded portion).

[0080] (4) Fourth Modification Fig. 8 is a diagram showing a fourth modified example of the laminated electrode body 100. As shown in Fig. 8, in the laminated electrode body 100D, like the laminated electrode body 100, the separators 130 are welded to each other on the second side surface 182 along the length of the laminated electrode body 100D in the D1 direction. Specifically, the separators 130 are welded to each other at each of a plurality of locations spaced apart in the D2 direction along the length of the laminated electrode body 100D in the D1 direction. The separators 130 are welded to each other directly.

[0081] Similar to the laminated electrode body 100C, the laminated electrode body 100D has multiple welded portions U2, U3, U4, and U5 formed by welding the separators 130 together. Unlike the laminated electrode body 100C, the laminated electrode body 100D has welded portions U5, U4, U3, and U2, which are present in this order from the second end face 186 toward the first end face 185.

[0082] In the stacked electrode body 100D, the length (width) of the welded portions U2, U3, U4, and U5 in the direction D2 is shorter the closer the welded portion is to the fifth surface 25 (the surface on the first end surface 185 side) of the container 2. That is, the closer the welded portions U2, U3, U4, and U5 are to the liquid inlet 2h, the shorter the length (width) of the welded portions in the direction D2.

[0083] The laminated electrode body 100D configured in this manner can provide the same effects as the laminated electrode body 100. In addition, when the electrolyte solution is poured into the container 2, the electrolyte solution that moves (falls) from the first end face 185 side to the opposite side from the pouring hole 2h can be efficiently impregnated into the laminated electrode body 100D.

[0084] (5) Fifth Modification Fig. 9 is a diagram showing a fifth modified example of the laminated electrode body 100. As shown in Fig. 9, in the laminated electrode body 100E, like the laminated electrode body 100, the separators 130 are welded to each other on the second side surface 182 along the length of the laminated electrode body 100E in the D1 direction. Specifically, the separators 130 are welded to each other at multiple locations spaced apart in the D2 direction along a length that is shorter than the length (thickness) of the laminated electrode body 100E in the D1 direction. The separators 130 are welded to each other directly.

[0085] The stacked electrode body 100E has a plurality of welded portions U6 and a plurality of welded portions U7 formed by welding the separators 130 together. In the stacked electrode body 100E, the welded portions U6 and the welded portions U7 are formed alternately in the D2 direction. When the stacked electrode body 100E is viewed, for example, in the D21 direction, the welded portions U6 and the welded portions U7 partially overlap in the D1 direction. This overlap fixes the positions of all the separators 130 relative to one another.

[0086] More specifically, the welded portions U6 are formed at equal intervals in the D2 direction. The welded portions U6 are formed in the D1 direction from the second main surface 184 toward the first main surface 183. The welded portions U6 do not reach the first main surface 183. The welded portions U6 extend from the second main surface 184 to a position between the middle of the second side surface 182 and the position of the first main surface 183 in the D1 direction.

[0087] Similarly, the welded portions U7 are formed at equal intervals in the D2 direction. The welded portions U7 are formed in the D1 direction from the first main surface 183 toward the second main surface 184. The welded portions U7 do not reach the second main surface 184. The welded portions U7 extend from the first main surface 183 to a position between the middle of the second side surface 182 and the position of the second main surface 184 in the D1 direction.

[0088] According to the laminated electrode body 100E having such a configuration, the same effects as those of the laminated electrode body 100 can be obtained.

[0089] (6) Sixth Modification Fig. 10 is a diagram showing a sixth modified example of the laminated electrode body 100. As shown in Fig. 10, in the laminated electrode body 100F, similar to the laminated electrode body 100, the separators 130 are welded to each other on the second side surface 182 along the length of the laminated electrode body 100F in the D1 direction. The separators 130 are welded directly to each other.

[0090] One welded portion U8 is formed in the laminated electrode body 100F. When the second side surface 182 is viewed in the direction D31, the welded portion U8 has an X-shape. At both ends of the second side surface 182 in the direction D2, the welded portion U8 welds the separators 130 to each other in two regions spaced apart in the direction D1. At the center of the second side surface 182 in the direction D2, the separators 130 are welded to each other only in one continuous region in the direction D1.

[0091] The laminated electrode body 100C having such a configuration can provide the same effects as the laminated electrode body 100. Furthermore, it becomes easy to weld all of the separators 130 in a single welding process.

[0092] [Embodiment 2] In this embodiment, differences from the power storage module 1 according to the first embodiment will be described.

[0093] 11 is a cross-sectional view of an energy storage module 1A according to the present embodiment. As shown in Fig. 11, the energy storage module 1A includes a housing 2, a stacked electrode assembly 100, plate-like members 201 and 202, tape members 301 and 302, an insulating sheet 500, and a plate-like member 400.

[0094] The energy storage module 1A differs from the energy storage module 1 of the first embodiment in that it includes a plate-shaped member 400. The plate-shaped member 400 is located between the stacked electrode body 100 and the plate-shaped member 202. The plate-shaped member 400 also extends in the D2 direction. The plate-shaped member 400 is typically made of a resin material.

[0095] In the energy storage module 1A, similarly to the energy storage module 1, the separators 130 are welded to the second side surface 182 along the length of the stacked electrode body 100 in the D1 direction. More specifically, in the energy storage module 1A, the separators 130 of the stacked electrode body 100 are welded to the plate-shaped member 400. In this way, in the energy storage module 1A, the separators 130 are welded to each other via the plate-shaped member 400.

[0096] The plate-like member 400 is preferably made up of a plurality of element members arranged at intervals in the direction D2. Each element member may be placed, for example, at a position corresponding to the welded portion U1 in Fig. 4, and each separator 130 and each element member may be thermally welded. The arrangement of each element member is not limited to this, and they may also be placed at positions corresponding to the welded portions in Figs. 5 to 11.

[0097] The energy storage module 1A configured as described above can achieve the same effects as those achieved by the energy storage module 1 of embodiment 1. Furthermore, since the energy storage module 1A uses the plate-like members 400, it is easier to fix the separators 130 in position compared to the configuration in which the separators 130 are directly welded to each other as in embodiment 1.

[0098] Like the energy storage module 1 according to embodiment 1, the energy storage module 1A includes a stacked electrode body 100. Therefore, as described in embodiment 1, this embodiment also makes it possible to prevent the separators 130 from shifting in position, and to reduce the space that does not contribute to charging and discharging.

[0099] The plate-shaped member 400 may be located between the laminated electrode body 100 and the plate-shaped member 201. A plate-shaped member 400 may be provided between the laminated electrode body 100 and the plate-shaped member 202, and between the laminated electrode body 100 and the plate-shaped member 201.

[0100] 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]

[0101] 1, 1A Energy storage module, 2 Housing, 2h Inlet hole, 21 First surface, 22 Second surface, 23 Third surface, 24 Fourth surface, 25 Fifth surface, 26 Sixth surface, 27 External connection terminal, 100, 100A, 100B, 100C, 100D, 100E, 100F 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, 185 First end surface, 186 Second end surface, 201, 202, 400 Plate-shaped member, 301, 302 Tape material, 500 Insulating sheet, T Weld area, U1, U2, U3, U4, U5, U6, U7, U8 weld area.

Claims

1. A laminated electrode body, A plurality of electrodes; a plurality of separators; the electrodes and the separators are stacked alternately in a first direction, The laminated electrode body is extending in a second direction perpendicular to the first direction; further comprising a circumferential surface extending in the second direction; a length of each of the separators in a third direction perpendicular to the first direction and the second direction is longer than a length of each of the electrodes in the third direction; 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, each of which is continuous with the first and second main surfaces; A laminated electrode body, wherein each of the separators is welded to at least one of the first side surface and the second side surface over the length of the laminated electrode body in the first direction.

2. The stacked electrode body according to claim 1 , wherein the separators are welded to each other at each of a plurality of locations spaced apart in the second direction over the length of the stacked electrode body in the first direction.

3. The laminated electrode body according to claim 1 ; a housing that houses the stacked electrode body, The container has a liquid injection hole formed therein for injecting an electrolyte into the container, the liquid injection hole is formed at an end of the container on the second direction side and is closer to the first side surface than to the second side surface; The energy storage module, wherein each of the separators is welded only to the second side surface out of the first side surface and the second side surface.

4. the separators are welded to each other at each of a plurality of locations spaced apart in the second direction over the length of the stacked electrode body in the first direction, The energy storage module according to claim 3 , wherein the lengths of the plurality of locations in the second direction are shorter as the locations become more distant from the liquid injection hole.

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