Power storage device

Abstract

To provide a power storage device that can easily measure an internal pressure after reduced-pressure sealing.SOLUTION: A power storage device includes: a power storage module having an electrode body and a main surface and a peripheral surface perpendicular to the main surface; a structure having an outer surface and an inner surface on a peripheral surface side of the outer surface and disposed in a state of facing the peripheral surface; and an exterior body that accommodates the power storage module and the structure. The exterior body includes a laminate sheet body disposed so as to cover the outer surface. Between the inner surface and the peripheral surface, an internal space sealed by the laminate sheet body is formed. The internal space is decompressed so as to have a negative pressure relative to an air pressure of an outer space of the power storage device. In the structure, a penetration hole penetrating from the inner surface to the outer surface is formed.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Conventionally, various power storage devices have been known. Japanese Patent Application Laid-Open No. 2004-134210 (Patent Document 1) discloses a bipolar laminated battery as an example of a power storage device. In the laminated battery, sheet-like electrodes are laminated with an electrolyte layer interposed therebetween. In the laminated battery, the electrodes are laminated on the outermost layer of the lamination so that the current collector contained in the electrode is exposed to the outside of the battery in the lamination direction of the electrode and functions as a terminal.

[0003] Specifically, a laminate sheet having an opening provided in the center is placed on each current collector of the two outermost electrodes. The four sides of each laminate sheet are sealed, and further, the edge of the opening of each laminate sheet is attached to the current collector with a seal resin, whereby the four sides of the bipolar electrode and the electrolyte layer are hermetically sealed under reduced pressure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the laminated battery of Patent Document 1, it is difficult to measure the internal pressure of the laminated battery after hermetic sealing under reduced pressure. Therefore, the present disclosure provides a power storage device capable of easily measuring the internal pressure after hermetic sealing under reduced pressure.

Means for Solving the Problems

[0006] According to an aspect of the present disclosure, an energy storage device includes an energy storage module having an electrode body and having a main surface and a peripheral surface perpendicular to the main surface, a structure having an outer surface and an inner surface on the peripheral surface side rather than the outer surface, and being disposed in a state facing the peripheral surface, and an exterior body that houses the energy storage module and the structure. The exterior body includes a laminate sheet body disposed so as to cover the outer surface. An internal space sealed by the laminate sheet body is formed between the inner surface and the peripheral surface. The internal space is depressurized so as to be in a negative pressure with respect to the atmospheric pressure of the external space of the energy storage device. A through hole penetrating from the inner surface to the outer surface is formed in the structure.

[0007] According to such a configuration, when the outer portion corresponding to the through hole in the laminate sheet body is sucked (specifically, evacuated), when the pressure becomes the same as that of the internal space, the said portion is pulled. As a result, the said portion deforms outward. By an inspector or the like confirming the pressure at the time when such a change in state occurs, the pressure of the internal space of the energy storage device can be known. Therefore, according to the energy storage device, the internal pressure of the internal space after depressurization and sealing of the energy storage device can be easily measured.

[0008] Preferably, the electrode body is a laminated electrode body including a plurality of electrodes laminated in a first direction orthogonal to the main surface. The through hole extends in the first direction.

[0009] According to such a configuration, an inspector or the like may bring the suction portion of the suction device into contact with the main surface side of the energy storage module so that the laminate sheet body is sucked in the electrode lamination direction in the laminated electrode body. Therefore, the inspection becomes easier compared to a configuration in which suction is performed from the peripheral surface side of the energy storage module.

[0010] Preferably, the structure has a base portion extending in the first direction and a wall portion extending in a second direction parallel to the main surface and toward the peripheral surface from the base portion in a side view of the energy storage module. The through hole is formed in the wall portion.

[0011] According to such a configuration, the through hole can be extended in the first direction, and the internal space can be secured by the structure.

[0012] Preferably, the structure is box-shaped. According to such a configuration, the internal space can be sufficiently secured by the structure. Further, the laminate sheet body can be reinforced from the inside of the power storage device by the structure.

Effects of the Invention

[0013] According to the power storage device, the internal pressure after reduced-pressure sealing can be easily measured.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0016] Hereinafter, as an example of the power storage device, a laminated battery will be described as an example. The laminated battery is mounted on an electric vehicle such as a hybrid vehicle that can travel using the power of at least one of a motor and an engine, or an electric vehicle that travels with a driving force obtained by electric energy.

[0017] Furthermore, hereinafter, the stacking direction of the electrodes in the laminated battery will also be referred to as the "DR3 direction". The direction perpendicular to the stacking direction and the short-side direction of the laminated battery will also be referred to as the "DR1 direction". The direction perpendicular to the stacking direction and the long-side direction of the laminated battery will also be referred to as the "DR2 direction". The DR1 direction, the DR2 direction, and the DR3 direction are perpendicular to each other.

[0018] FIG. 1 is a perspective view of the laminated battery according to the present embodiment. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 1. With reference to FIGS. 1 to 3, the laminated battery 100 according to the present embodiment will be described.

[0019] As shown in FIGS. 1 to 3, the laminated battery 100 includes a power storage module 1 having a laminated electrode body 10 in which a plurality of electrodes (electrode plates 11) described later are laminated in the stacking direction and a resin sealing body 40, a structure 60 (FIG. 3), and an exterior body 20 that houses the power storage module 1 and the structure 60.

[0020] The power storage module 1 further has a first main surface 91, a second main surface 92 opposite to the first main surface 91, and a peripheral surface 93. The first main surface 91 and the second main surface 92 are end surfaces in the DR3 direction. The first main surface 91 and the second main surface 92 are parallel. The first main surface 91 and the second main surface 92 are surfaces that extend in the DR1 direction and the DR2 direction. The first main surface 91 is a surface that contacts a first conductive plate 18 described later. The second main surface 92 is a surface that contacts a second conductive plate 19 described later.

[0021] The circumferential surface 93 is a plane perpendicular to the first main surface 91 and the second main surface 92. In this example, the circumferential surface 93 is composed of four end surfaces 93a to 93d (see FIGS. 2, 3, and 7). Each of the end surfaces 93a to 93d is a side surface of the resin-sealed body 40. In this example, each of the end surfaces 93a to 93d is a rectangular plane.

[0022] The exterior body 20 is electrically connected to the terminal electrodes of the laminated electrode body 10 described later and is provided so as to be able to extract current to the outside from the above-described lamination direction. The exterior body 20 includes a first conductive plate 18, a second conductive plate 19, a first laminate sheet portion 21, a second laminate sheet portion 22, and a resin sheet 50. The laminated battery 100 is, for example, a secondary battery such as a lithium-ion battery.

[0023] The laminated electrode body 10 includes a plurality of electrode plates 11, a plurality of separators 15, a positive electrode terminal electrode 16, and a negative electrode terminal electrode 17. The plurality of electrode plates 11, the positive electrode terminal electrode 16, and the negative electrode terminal electrode 17 are laminated in the lamination direction (DR3 direction in FIGS. 2 and 3) with the separator 15 interposed therebetween.

[0024] The separator 15 is formed in a sheet shape. Examples of the separator 15 include a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, methyl cellulose, or the like. The separator 15 may be reinforced with a vinylidene fluoride resin compound.

[0025] The plurality of electrode plates 11 are provided between the positive electrode terminal electrode 16 and the negative electrode terminal electrode 17. The electrode plate 11 is, for example, a bipolar electrode. The electrode plate 11 includes a current collector 12, a positive electrode layer 13, and a negative electrode layer 14.

[0026] The current collector 12 may contain, for example, at least one selected from the group consisting of aluminum (Al), stainless steel, nickel (Ni), chromium (Cr), platinum (Pt), niobium (Nb), iron (Fe), titanium (Ti), and zinc (Zn). Further, the current collector 12 may be obtained by plating the surface of a metal foil.

[0027] The current collector 12 has a first surface 12a located on one side in the stacking direction and a second surface 12b located on the other side in the stacking direction. The negative electrode layer 14 is provided on the first surface 12a. The positive electrode layer 13 is provided on the second surface 12b.

[0028] The positive electrode terminal electrode 16 is located on one side in the stacking direction. The positive electrode terminal electrode 16 includes the current collector 12 and the positive electrode layer 13. Specifically, in the positive electrode terminal electrode 16, the negative electrode layer 14 and the positive electrode layer 13 are not provided on the first surface 12a of the current collector 12, and the positive electrode layer 13 is provided on the second surface 12b of the current collector 12. A first conductive plate 18 is disposed on the first surface 12a of the current collector 12 in the positive electrode terminal electrode 16. Note that the central portion (portion excluding the peripheral portion) of the first surface 12a of the current collector 12 in the positive electrode terminal electrode 16 constitutes a part of the first main surface 91. The first main surface 91 includes the central portion of the first surface 12a of the current collector 12 in the positive electrode terminal electrode 16 and the upper surface of the resin sealing body 40.

[0029] The negative electrode terminal electrode 17 is located on the other side in the stacking direction. The negative electrode terminal electrode 17 includes the current collector 12 and the negative electrode layer 14. Specifically, in the negative electrode terminal electrode 17, the negative electrode layer 14 is provided on the first surface 12a of the current collector 12, and the negative electrode layer 14 and the positive electrode layer 13 are not provided on the second surface 12b of the current collector 12. A second conductive plate 19 is disposed on the second surface 12b of the current collector 12 in the negative electrode terminal electrode 17. Note that the central portion (portion excluding the peripheral portion) of the second surface 12b of the current collector 12 in the negative electrode terminal electrode 17 constitutes a part of the second main surface 92. The second main surface 92 includes the central portion of the second surface 12b of the current collector 12 in the negative electrode terminal electrode 17 and the lower surface of the resin sealing body 40.

[0030] The positive electrode layer 13 is formed by coating a positive electrode active material on the second surface 12b. As the positive electrode active material, for example, those capable of occluding and releasing charge carriers such as lithium ions can be adopted. Specifically, as the positive electrode active material, a lithium ion composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, a polyanion-based compound, etc., which can be used as the positive electrode active material of a lithium ion secondary battery, can be adopted. Also, two or more positive electrode active materials may be used in combination. For example, the positive electrode active material may contain olivine-type lithium iron phosphate (LiFePO4).

[0031] The negative electrode layer 14 is formed by coating a negative electrode active material on the first surface 12a. As the negative electrode active material, for example, lithium, carbon, a metal compound, and an element or its compound capable of alloying with lithium, etc., can be adopted.

[0032] Note that in any of the plurality of electrode plates 11, the negative electrode terminal electrode 17, and the positive electrode terminal electrode 16, the peripheral portion of the current collector 12 is an uncoated region where the positive electrode layer 13 and the negative electrode layer 14 are not provided.

[0033] The resin sealing body 40 is provided so as to seal the periphery of the laminated electrode body 10. Specifically, the resin sealing body 40 seals the cell space formed between two adjacent electrode plates 11. An electrolytic solution is injected into the cell space. The resin sealing body 40 is formed by curing a resin member such as a hot melt member, a thermoplastic resin, a thermosetting resin, or a photocurable resin. The resin sealing body 40 is provided in the above-mentioned uncoated region.

[0034] The first conductive plate 18 and the second conductive plate 19 are provided so as to sandwich the laminated electrode body 10 in the stacking direction. Specifically, the first conductive plate 18 is disposed on the first surface 12a of the current collector 12 included in the positive terminal electrode 16. That is, the first conductive plate 18 is disposed on the first main surface 91 of the current collector 12 included in the positive terminal electrode 16. The first conductive plate 18 is electrically connected to the positive terminal electrode 16 by being disposed in contact with the first surface 12a. The first conductive plate 18 functions as the positive electrode terminal of the laminated battery 100 by being electrically connected to the positive terminal electrode 16.

[0035] The second conductive plate 19 is disposed on the second surface 12b of the current collector 12 included in the negative terminal electrode 17. That is, the second conductive plate 19 is disposed on the second main surface 92 of the current collector 12 included in the negative terminal electrode 17. The second conductive plate 19 is electrically connected to the negative terminal electrode 17 by being disposed in contact with the second surface 12b. The second conductive plate 19 functions as the negative electrode terminal of the laminated battery 100 by being electrically connected to the negative terminal electrode 17.

[0036] In the laminated battery 100, it is possible to draw out the current to the outside from the power storage module 1 accommodated inside through the first conductive plate 18 functioning as the positive electrode terminal and the second conductive plate 19 functioning as the negative electrode terminal without using a tab for drawing out the current to the outside.

[0037] The first conductive plate 18 and the second conductive plate 19 have a rectangular shape having a plurality of corners. The peripheries of the first conductive plate 18 and the second conductive plate 19 are located on the resin sealing body 40.

[0038] In this example, the first conductive plate 18 and the second conductive plate 19 are plates made of aluminum (Al). However, they are not limited to this. The first conductive plate 18 and the second conductive plate 19 may contain at least one selected from the group consisting of aluminum (Al), stainless steel, nickel (Ni), chromium (Cr), platinum (Pt), niobium (Nb), iron (Fe), titanium (Ti), and zinc (Zn). Also, the current collector 12 may be a metal foil with plating applied to its surface.

[0039] The first laminate sheet portion 21 is joined to the peripheral edge of the first conductive plate 18. The first laminate sheet portion 21 is joined to the first conductive plate 18 with a resin sheet 50 interposed between the first laminate sheet portion 21 and the peripheral edge of the first conductive plate 18. The second laminate sheet portion 22 is joined to the peripheral edge of the second conductive plate 19. The second laminate sheet portion 22 is joined to the second conductive plate 19 with a resin sheet 50 interposed between the second laminate sheet portion 22 and the peripheral edge of the second conductive plate 19.

[0040] In this example, the resin sheet 50 is formed of a resin material having insulating properties. The resin sheet 50 is formed of a resin material that can be welded to the first conductive plate 18 and the second conductive plate 19. In this example, the resin sheet 50 is a sealing film for insulation.

[0041] Specifically, the resin sheet 50 has resin layers 51, 52, 53. The resin layer 51 is the inner layer. The resin layer 53 is the outer layer. The resin layer 52 is sandwiched between the resin layer 51 and the resin layer 53.

[0042] The resin layers 51, 53 are sealant resin layers. As also shown in states (B) and (C) of FIG. 6 described later, in this example, the resin layers 51, 53 are layers of acid-modified PP (PPa). The resin layer 51 is thermally welded to the first conductive plate 18. The resin layer 52 is, in this example, a layer of polypropylene (PP).

[0043] Note that the types of resins constituting the resin layers 51 to 53 are not limited to the above. For example, heat-sealable resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene can be appropriately adopted.

[0044] The central portions of the first conductive plate 18 and the second conductive plate 19 are exposed areas that are not covered by the resin sheet 50, the first laminate sheet portion 21, and the second laminate sheet portion 22. Through the exposed areas, current can be directly taken out from the power storage module 1 housed inside to the outside.

[0045] The first laminate sheet portion 21 includes a plurality of first sheets 31 and a plurality of second sheets 32 (see FIGS. 2, 3, and 6). The plurality of first sheets 31 and the plurality of second sheets 32 cooperate to cover the periphery of the first conductive plate 18. The second laminate sheet portion 22 includes a plurality of first sheets 31 and a plurality of second sheets 32. The plurality of first sheets 31 and the plurality of second sheets 32 included in the second laminate sheet portion 22 cooperate to cover the periphery of the second conductive plate 19.

[0046] The first sheet 31 (see FIG. 2) has a first metal layer 310 and sealant resin layers 311 and 312. The first metal layer 310 has a sheet shape. In this example, as shown in state (E) of FIG. 6 described later, the first metal layer 310 is a layer of aluminum foil (Al foil). The first metal layer 310 is not limited to Al foil, and metal foils such as Ni foil, Cu foil, and stainless steel foil can also be used. The first metal layer 310 imparts moisture resistance, air permeability resistance, and chemical resistance to the first sheet 31.

[0047] The sealant resin layers 311 and 312 are provided on both sides of the first metal layer 310. Specifically, the sealant resin layer 311 is provided on the inner surface of the first metal layer 310. The sealant resin layer 312 is provided on the outer surface of the first metal layer 310.

[0048] The sealant resin layers 311 and 312 are compatible with the resin sheet 50. In this example, the sealant resin layers 311 and 312 employ polypropylene (PP), but are not limited thereto. The sealant resin layers 311 and 312 may employ, for example, heat-sealable resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene.

[0049] The sealant resin layers 311 and 312 function as a seal layer of the exterior body 20. Further, the sealant resin layers 311 and 312 also have a function as an insulating layer, and insulate the first laminate sheet portion 21 and the second laminate sheet portion 22 when the first laminate sheet portion 21 and the second laminate sheet portion 22 are joined.

[0050] The second sheet 32 (see FIG. 3) has a second metal layer 320, a first resin layer 321, a second resin layer 322, a third resin layer 323, and a fourth resin layer 324. In the second sheet 32, the third resin layer 323, the first resin layer 321, the second metal layer 320, the second resin layer 322, and the fourth resin layer 324 are laminated in this order from the inside to the outside of the laminated battery 100. The fourth resin layer 324 is the outermost layer of the second sheet 32.

[0051] In this example, as also shown in the state (F) of FIG. 6 described later, the second metal layer 320 is a layer of Al foil. The first resin layer 321 is a layer of acid-modified PP (PPa). The second resin layer 322 is a layer of nylon. The third resin layer 323 is a layer of polypropylene (PP). The outermost fourth resin layer 324 is a layer of polyethylene terephthalate (PET). The first resin layer 321 is provided on the first main surface 320a. The second resin layer 322 is provided on the second main surface 320b.

[0052] The second metal layer 320 has a sheet shape. The second metal layer 320 has a first main surface 320a and a second main surface 320b. The first main surface 320a is a surface facing the inside (the side where the laminated electrode body 10 is located), and the second main surface 320b is a surface facing the outside (the side opposite to the side where the laminated electrode body 10 is located).

[0053] The second metal layer 320 is not limited to an Al foil, and metal foils such as Ni foil, Cu foil, and stainless steel foil can be used. The thickness of the second metal layer 320 may be thicker than that of the first metal layer 310. The thickness of the second metal layer 320 and the thickness of the first metal layer 310 may be the same.

[0054] The third resin layer 323 is compatible with the sealant resin layer 312. As the third resin layer 323, in addition to polypropylene (PP), for example, heat-sealable resins such as polyethylene, modified polyethylene, and modified polypropylene can also be adopted. For the fourth resin layer 324, it is preferable to use a resin material that is incompatible with the sealant resin layer 312.

[0055] In the second sheet 32, a nylon layer (second resin layer 322) and a polyethylene terephthalate layer (fourth resin layer 324) are stacked outside the second metal layer 320. Therefore, the combination of the layers outside the second metal layer 320 is higher in strength than the combination of the two layers (first resin layer 321, third resin layer 323) inside the second metal layer 320 in the second sheet 32. Note that "higher strength" means high rigidity or tensile strength. Thereby, breakage of the second metal layer 320 when the second sheet 32 receives an external force such as being pierced can be suitably prevented.

[0056] Incidentally, as described above, the sealant resin layer 312 of the first sheet 31 (see FIG. 2) is a layer of polypropylene (PP). Therefore, the combination of the layers outside the second metal layer 320 of the second sheet 32 is higher in strength than the sealant resin layer 312 of the first sheet 31. Therefore, the combination of the layers outside the second metal layer 320 in the second sheet 32 becomes higher in strength than the sealant resin layer 312 of the first sheet 31. By increasing the strength of the second sheet 32, breakage of the second sheet 32 during the deep drawing forming described later can be suitably prevented.

[0057] The first laminated sheet portion 21 is drawn deep in a state of being joined to the first conductive plate 18. That is, drawing is performed on the first laminated sheet portion 21. As a result, the first laminated sheet portion 21 has a shape that opens upward and downward. A flange portion 21f bent outward is provided at the lower opening end of the first laminated sheet portion 21.

[0058] The second laminated sheet portion 22 is drawn deep in a state of being joined to the second conductive plate 19. That is, drawing is also performed on the second laminated sheet portion 22 in the same manner as the first laminated sheet portion 21. As a result, the second laminated sheet portion 22 has a shape that opens upward and downward. A flange portion 22f bent outward is provided at the upper opening end of the second laminated sheet portion 22.

[0059] The first laminated sheet portion 21 and the second laminated sheet portion 22 are provided with accommodation recesses 21c and 22c for accommodating the power storage module 1 inside. The accommodation recesses 21c and 22c cover a part of the first main surface 91, a part of the second main surface 92, and the peripheral surface 93 of the power storage module 1.

[0060] Specifically, the accommodation recesses 21c and 22c cover the peripheral portions of the upper surface and the lower surface of the power storage module 1, and the peripheral surface of the power storage module 1. Specifically, the accommodation recesses 21c and 22c cover the peripheral portions of the upper surface and the lower surface of the laminated electrode body 10, and the peripheral surface of the laminated electrode body 10. The central portion of the upper surface of the laminated electrode body 10 is covered by the first conductive plate 18. The central portion of the lower surface of the laminated electrode body 10 is covered by the second conductive plate 19.

[0061] The accommodating recesses 21c and 22c are constituted by, for example, portions formed by subjecting the first laminate sheet portion 21 and the second laminate sheet portion 22 to the above-described squeezing process. Note that the accommodating recesses 21c and 22c are not limited to such portions, and may be provided as long as they can accommodate the laminated electrode body 10. In the above description, the case where accommodating recesses are provided in both the first laminate sheet portion 21 and the second laminate sheet portion 22 is exemplified, but the accommodating recess may be provided in only one of the first laminate sheet portion 21 and the second laminate sheet portion 22.

[0062] The first sheet 31 has an inner end portion 31i located on the central side of the laminated electrode body 10. The second sheet 32 has an inner end portion 32i located on the central side of the laminated electrode body 10. The resin sheet 50 has an inner edge portion 50i and an outer edge portion 50c located on the central side of the laminated electrode body 10.

[0063] In order to ensure an insulation distance between the first metal layer 310 of the first sheet 31 and the second metal layer 320 of the second sheet 32, and the first conductive plate 18 and the second conductive plate 19, the inner edge portion 50i is located on the central side of the laminated electrode body 10 with respect to the inner end portions 31i and 32i.

[0064] The first conductive plate 18 has an outer edge portion 18c. The second conductive plate 19 has an outer edge portion 19c. The inner end portions 31i and 32i are located on the central side of the laminated electrode body 10 with respect to the outer edge portions 18c and 19c.

[0065] The portions where the first conductive plate 18 and the second conductive plate 19 overlap with the resin sheet 50 are welded. The bonding interface of the overlapping portions is sealed.

[0066] The outer edge portion 50c of the resin sheet 50 is located outside the outer edge portions 18c and 19c, but is not limited thereto, and the outer edge portion 50c and the outer edge portions 18c and 19c may be flush.

[0067] By joining the first sheet 31 and the second sheet 32 to the first conductive plate 18 and the second conductive plate 19 via the resin sheet 50, short - circuiting between the first conductive plate 18 and the second conductive plate 19 through the first sheet 31 having the first metal layer 310 or the second sheet 32 having the second metal layer 320 is suppressed.

[0068] Next, the structure 60 will be described. As described above, the structure 60 is housed in the exterior body 20. As shown in FIG. 3, the structure 60 is arranged in a state of facing the peripheral surface 93 (specifically, the end surfaces 93a, 93c) of the power storage module 1.

[0069] FIG. 4 is a perspective view of the structure 60. As shown in FIG. 4, in this example, the structure 60 is box - shaped. The structure 60 is typically formed of resin. The structure 60 includes a base 61 extending in the DR3 direction in a side view (see FIG. 3) of the power storage module 1.

[0070] The structure 60 further includes two wall portions 62, 64 extending in the DR2 direction parallel to the first main surface 91 of the power storage module 1 and toward the peripheral surface 93 from the base 61. The structure 60 further includes two wall portions 63, 65 extending in the DR2 direction perpendicular to the first main surface 91 and toward the peripheral surface 93 from the base 61.

[0071] Each of the wall portions 62, 63, 64, 65 rising from the base 61 is continuous in this order. The wall portion 62 is located on the side of the first conductive plate 18. The wall portion 64 is located on the side of the second conductive plate 19. The base 61 and the wall portions 62, 63, 64, 65 form a rectangular parallelepiped - shaped space 690 having an opening.

[0072] The structure 60 has an outer surface 60s and an inner surface 60t on the side of the peripheral surface 93 rather than the outer surface 60s. A through - hole 60h penetrating from the inner surface 60t to the outer surface 60s is formed in the structure 60. Specifically, in this example, the through - hole 60h is formed in the wall portion 62. The through - hole 60h is formed in the central portion of the wall portion 62 in the DR3 direction.

[0073] The first and second laminate sheet portions 21 and 22 (see FIG. 1) constituting the exterior body 20 are arranged to cover the outer surface 60s of the structure 60. Specifically, each second sheet 32 (see FIG. 3) of the first and second laminate sheet portions 21 and 22 is arranged to cover the outer surface 60s of the structure 60. As shown in FIG. 3, the opening end on the outer surface 60s side of the through hole 60h is covered by the second sheet 32 of the first laminate sheet portion 21.

[0074] Between the inner surface 60t of the portion of the base 61 in the structure 60 and the end face 93a of the power storage module 1, as shown in FIG. 3, a sealed internal space 800 is formed by each second sheet 32 of the first and second laminate sheet portions 21 and 22. The internal space 800 is depressurized to a negative pressure with respect to the atmospheric pressure (in this example, atmospheric pressure) of the external space of the laminated battery 100. In this example, the internal space 800 is depressurized to about 1 kPa (kilo Pascal) in the initial state. The internal space 800 is in a low vacuum state by evacuation. Due to the pressure difference between the internal space 800 of the laminated battery 100 and the external space caused by such depressurization, a restraining force is applied to the laminated electrode body 10.

[0075] As described above, the laminated battery 100, which is an example of a power storage device, has a laminated electrode body 10 and includes a power storage module 1 having first and second main surfaces 91 and 92 and a peripheral surface 93 perpendicular to the first and second main surfaces 91 and 92. As shown in FIGS. 3 and 4, the laminated battery 100 has an outer surface 60s and an inner surface 60t on the side of the peripheral surface 93 rather than the outer surface 60s, and further includes a structure 60 arranged in a state facing the peripheral surface 93. As shown in FIGS. 2 and 3, the laminated battery 100 further includes an exterior body 20 that houses the power storage module 1 and the structure 60.

[0076] As shown in FIG. 3, the outer package 20 further includes first and second laminate sheet portions 21 and 22 arranged to cover the outer surface 60s. As shown in FIG. 3, an internal space 800 sealed by the first and second laminate sheet portions 21 and 22 is formed between the inner surface 60t and the peripheral surface 93. The internal space 800 is depressurized to a negative pressure with respect to the atmospheric pressure in the external space of the laminated battery 100. As shown in FIGS. 3 and 4, a through hole 60h penetrating from the inner surface 60t to the outer surface 60s is formed in the structure 60.

[0077] Incidentally, there is a possibility that air (nitrogen, oxygen, etc.) from outside the laminated battery 100 may enter the internal space 800 of the laminated battery 100. For example, when there is a problem with the welding between the first laminate sheet portion 21 and the second laminate sheet portion 22, air may enter through the gap between the flange portion 21f and the flange portion 22f. Therefore, after the laminated battery 100 is manufactured and before shipment of the laminated battery 100 or before mounting on a vehicle, it is required to inspect the pressure (internal pressure) of the internal space 800.

[0078] FIG. 5 is a diagram for explaining a method of measuring the internal pressure of the internal space 800 in the laminated battery 100. As shown in FIG. 5, the internal pressure of the internal space 800 is measured by an inspection device 900. The inspection device 900 includes a suction device 910, a pressure gauge 920, a chamber 930, and a pipe 940. The suction device 910, the pressure gauge 920, and the chamber 930 are connected to each other by the pipe 940. In this example, the chamber means a member that forms a space, not the space itself.

[0079] The suction device 910 includes a pump, a control device, etc. (not shown). The chamber 930 includes a main body 931 and an O-ring 932. In this example, the main body 931 has a shape with the container upside down. In this example, the main body 931 is transparent. The main body 931 is formed of resin or the like. The open end (lower end) of the main body 931 is ring-shaped. The O-ring 932 is attached to the open end with an adhesive or the like. A through hole 923 for inserting the pipe 940 into the chamber 930 is formed on the side surface of the main body 931.

[0080] During the inspection by the inspection device 900, the inspector moves at least one of the inspection device 900 and the laminated battery 100 so that the chamber 930 is positioned above the through hole 60h of the structure 60 and the O-ring 932 is pressed against the second sheet 32. Specifically, in a top view of the laminated battery 100, the inspector relatively moves the inspection device 900 and the laminated battery 100 so that the through hole 60h is positioned inside the O-ring 932 and the O-ring 932 is pressed against the fourth resin layer 324 of the second sheet 32. That is, in a top view of the laminated battery 100, the inspection device 900 and the laminated battery 100 are relatively moved so that the open end of the outer surface 60s of the through hole 60h is surrounded by the O-ring 932 and the O-ring 932 contacts the fourth resin layer 324. Note that at least one of the inspection device 900 and the laminated battery 100 may be moved.

[0081] In this state, the inspector operates the suction device 910 to suck the air in the chamber 930. Due to this suction, the pressure in the chamber 930 begins to decrease. The inspector can confirm the pressure in the chamber 930 with the pressure gauge 920.

[0082] As suction further progresses and the pressure in the chamber 930 falls below the pressure in the internal space 800 of the laminated battery 100, the second sheet 32 of the first laminate sheet portion 21 is pulled toward the chamber 930 side. As a result, as shown in FIG. 5, a part of the second sheet 32 is drawn into the chamber 930. That is, the portion of the second sheet 32 that covered the through-hole 60h assumes a convex state upward. The inspector can know the pressure in the internal space 800 of the laminated battery 100 by checking the value (in this example, the memory) of the pressure gauge 920 when such a change in state occurs. That is, according to the laminated battery 100, the internal pressure of the internal space 800 after decompression sealing of the laminated battery 100 can be easily measured.

[0083] With the inspection device 900 as described above, since the pressure in the internal space 800 of the laminated battery 100 can be measured, the pressure in the internal space 800 can be measured without putting the entire power storage device in a chamber and evacuating it. If the power storage device is put in a chamber and evacuated, there is a risk that the restraint of the laminated electrode body 10 will be released due to deformation of the outermost conductor (the conductor corresponding to the first conductive plate 18 and the second conductive plate 19).

[0084] However, according to the laminated battery 100 of this example, it is not necessary to put the entire laminated battery 100 in a chamber. Therefore, the restraint of the laminated electrode body 10 is not released by measuring the pressure in the internal space 800. For this reason, a high-quality laminated battery 100 can be provided.

[0085] In this example, as shown in FIG. 4, the through-hole 60h extends in the D3 direction. Therefore, the inspector may press the chamber 930 against the second sheet 32 of the first laminate sheet portion 21 from above. Therefore, the inspection becomes easy. Further, compared with the configuration in which the through-hole 60h is formed in the base portion 61 (see FIG. 8), the degree of freedom in arranging the pipe 940 increases due to space constraints.

[0086] As shown in FIG. 4, the through hole 60h is formed in the wall portion 62. Therefore, the through hole 60h can be extended in the DR3 direction (lamination direction), and the internal space 800 can be secured by the structure 60. Further, the opening end on the outer surface 60s side of the through hole 60h can also be covered with the second sheet 32.

[0087] The structure 60 is box-shaped. Therefore, the internal space 800 can be sufficiently secured by the structure 60. Further, the second sheet 32 can be reinforced from the inside of the laminated battery 100 by the structure 60.

[0088] FIG. 6 is a diagram for explaining a method of manufacturing the first laminate sheet portion 21. As shown in state (A) of FIG. 6, an aluminum plate to be the first conductive plate 18 is prepared. As shown in state (B), two resin sheets 50 are welded along the two long sides of the aluminum plate. Next, as shown in state (C), two resin sheets 50 are welded along the two short sides of the aluminum plate. The resin sheets 50 on the long side and the resin sheets 50 on the short side overlap at the four corners shown in state (C).

[0089] As shown in state (D), two resin sheets 70 are welded to each of the two resin sheets 50 on the long side. Each resin sheet 70 has the same layer structure as the resin sheet 50 in this example. The two resin sheets 70 on the right side of the figure are spaced apart from each other in the DR2 direction and extend in the D1 direction. Similarly, the two resin sheets 70 on the left side of the figure are also spaced apart from each other in the DR2 direction and extend in the D1 direction. The four resin sheets 70 are welded to the resin sheets 50 on the long side in a state of protruding from the resin sheets 50 in the direction opposite to the aluminum plate.

[0090] As shown in state (E), one first sheet 31 is welded to the resin sheets 50 on the right side of the figure and the two resin sheets 70. Similarly, one first sheet 31 is also welded to the resin sheets 50 on the left side of the figure and the two resin sheets 70. Each first sheet extends in the DR2 direction. Each first sheet is longer than the separation distance between the resin sheets 70 in the DR2 direction.

[0091] As shown in state (F), one second sheet 32 is welded to the resin sheet 50 on the upper side of the figure, the two resin sheets 70 on the upper side of the figure, and the ends of the two first sheets 31 (the upper ends in the figure). The second sheet 32 is U-shaped. Similarly, one second sheet 32 is also welded to the resin sheet 50 on the lower side of the figure, the two resin sheets 70 on the lower side of the figure, and the ends of the two first sheets 31 (the lower ends in the figure). The second sheets 32 are spaced apart and face each other in the DR2 direction. Note that the intermediate of the first laminate sheet portion 21 shown as state (F) is line-symmetric in each of the DR1 direction and the DR2 direction.

[0092] By performing a drawing process on the intermediate along the virtual line L, as shown in state (G), the first laminate sheet portion 21 is generated. By the drawing process, the flange portion 21f of the first laminate sheet portion 21 is formed.

[0093] Note that the first laminate sheet portion 21 and the second laminate sheet portion 22 have the same shape. The second laminate sheet portion 22 is also manufactured in the same manner as the first laminate sheet portion 21. Therefore, the description of the manufacturing method of the second laminate sheet portion 22 will not be repeated here.

[0094] FIG. 7 is a diagram for explaining a method of manufacturing a laminated battery 100 using the power storage module 1, the structure 60, and the exterior body 20. As shown in states (A) and (B) of FIG. 7, the structure 60 is installed on one of the two short sides of the power storage module 1. The structure 60 is installed at a position facing the end face 93a that constitutes the peripheral surface 93 of the power storage module 1.

[0095] In this example, the laminated battery 100 further includes structures 60A and 60B. The structures 60A and 60B have the same structure and function as the structure 60. Through holes 60h are formed in the structures 60A and 60B. The structure 60A is shorter than the structure 60 in the DR1 direction. The structure 60B is longer than the structure 60 in the DR1 direction. The structures 60A and 60B are housed in the exterior body 20 in the same manner as the structure 60.

[0096] The structure 60A is installed on the same side as the structure 60. The structure 60A is installed such that the opening side faces the end face 93a, similar to the structure 60. The structure 60B is installed on the short side opposite to the structure 60. The structure 60B is installed at a position facing the end face 93c of the power storage module 1. Specifically, the structure 60B is installed such that the opening side faces the end face 93c. In the DR1 direction, the through hole 60h of the structure 60, the through hole 60h of the structure 60A, and the through hole 60h of the structure 60B are at different positions.

[0097] As shown in state (C), the power storage module 1 and the three structures 60, 60A, and 60B are sandwiched between the first laminate sheet portion 21 and the second laminate sheet portion 22. Note that the second laminate sheet portion 22 is in a reversed state. Then, by welding the first laminate sheet portion 21 and the second laminate sheet portion 22 to each other, the laminated battery 100 is completed as shown in state (D).

[0098] In addition, marks 990, 991, and 992 may be printed on the first laminate sheet portion 21 so that the positions of the through holes 60h are easily visible. The mark 990 indicates the position of the through hole 60h of the structure 60. The mark 991 indicates the position of the through hole 60h of the structure 60A. The mark 992 indicates the position of the through hole 60h of the structure 60B.

[0099] Note that the through holes 60h do not necessarily have to be formed in the structures 60A and 60B. It is sufficient if the through hole 60h is formed in any one of the structures 60, 60A, and 60B. When the pressure in the internal space 800 is automatically inspected by the inspection device 900, the marks 990, 991, and 992 are unnecessary.

[0100] <Modification Example> (1) FIG. 8 is a diagram showing a modification example of the laminated battery 100. As shown in FIG. 8, the laminated battery 100A is different from the laminated battery 100 in that it includes a structure 60Z instead of the structure 60.

[0101] In the structure 60Z, the through hole 60h is formed in the base portion 61 (see FIG. 4) instead of the wall portion 62. In such a configuration, the chamber 930 (FIG. 5) of the inspection device 900 may be pressed against the side portion of the second sheet 32 so as to move relatively in the DR2 direction.

[0102] (2) The shape of the structure 60 is not limited to a box shape. The structure 60 may have a shape such as an H-shaped steel extending in the DR2 direction. The structure 60 may have at least a shape having the base portion 61 and the wall portion 62. The shape of the base portion 61 is not limited to a rectangular parallelepiped shape. Notches (through holes or the like) may be formed in the base portion 61 and each of the wall portions 62 to 65 for weight reduction.

[0103] The embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

Description of Reference Numerals

[0104] 1 Energy storage module, 10 Stacked electrode body, 11 Electrode plate, 12 Current collector, 12a First surface, 12b Second surface, 13 Positive electrode layer, 14 Negative electrode layer, 15 Separator, 16 Positive electrode terminal electrode, 17 Negative electrode terminal electrode, 18 First conductive plate, 18c, 19c, 50c Outer edge portion, 19 Second conductive plate, 20 Exterior body, 21 First laminate sheet portion, 22 Second laminate sheet portion, 21c, 22c Accommodation recess, 21f, 22f Flange portion, 31 First sheet, 31i, 32i Inner end portion, 32 Second sheet, 40 Resin sealing body, 50, 70 Resin sheet, 50i Inner edge portion, 51, 52, 53 Resin layer, 60, 60A, 60B, 60Z Structure, 60h, 923 Through hole, 60s Outer surface, 60t Inner surface, 61 Base portion, 62, 63, 64, 65 Wall portion, 91, 320a First main surface, 92, 320b Second main surface, 93 Peripheral surface, 93a, 93b, 93c, 93d End face, 100, 100A Stacked battery, 310 First metal layer, 311, 312 Sealant resin layer, 320 Second metal layer, 321 First resin layer, 322 Second resin layer, 323 Third resin layer, 324 Fourth resin layer, 800 Internal space, 900 Inspection device, 910 Suction device, 920 Pressure gauge, 930 Chamber, 931 Body portion, 932 Ring, 940 Pipe, 990, 991, 992 Mark, L Virtual line.

Claims

1. A power storage device comprising: a power storage module having an electrode body and having a main surface and a peripheral surface perpendicular to the main surface; a structure having an outer surface and an inner surface on the peripheral surface side rather than the outer surface, and being arranged in a state of facing the peripheral surface; an exterior body that houses the power storage module and the structure; the exterior body includes a laminate sheet body arranged so as to cover the outer surface; an internal space sealed by the laminate sheet body is formed between the inner surface and the peripheral surface; the internal space is depressurized so as to have a negative pressure with respect to the atmospheric pressure of the external space of the power storage device; a power storage device, wherein a through hole penetrating from the inner surface to the outer surface is formed in the structure.

2. The electrode body is a laminated electrode body including a plurality of electrodes laminated in a first direction orthogonal to the main surface; The power storage device according to claim 1, wherein the through hole extends in the first direction.

3. The structure is: in a side view of the power storage module, a base portion extending in the first direction; and a wall portion extending from the base portion in a second direction parallel to the main surface and facing the peripheral surface; The power storage device according to claim 2, wherein the through hole is formed in the wall portion.

4. The power storage device according to claim 3, wherein the structure is box-shaped.

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