Electricity storage device

Abstract

The invention relates to a power storage device. A power storage device includes: a power storage module having an electrode body, a main surface, and an outer peripheral surface perpendicular to the main surface; a structural body having an outer surface and an inner surface further on the outer peripheral surface side than the outer surface, and disposed in a state facing the outer peripheral surface; and an outer body accommodating the power storage module and the structure. The outer body includes a laminated sheet body arranged to cover an outer surface. A sealed internal space is formed between the inner surface and the outer peripheral surface by the laminated sheet body. The internal space is evacuated so as to have a negative pressure with respect to the pressure of the external space of the electricity storage device. A through hole penetrating from the inner surface to the outer surface is formed in the structure.

Description

Technical Field

[0001] The present disclosure relates to an electricity storage device. Background Art

[0002] Various conventional electricity storage devices are known. Japanese Unexamined Patent Application Publication No. 2004-134210 (JP2004-134210 A) discloses a bipolar laminated battery as an example of an electricity storage device. In this laminated battery, a plurality of sheet-like electrodes are laminated, and an electrolyte layer is interposed therebetween. In the laminated battery, the electrodes are laminated at the outermost layer of the laminate such that a current collector included in the electrodes is exposed to the outside of the battery in the lamination direction of the electrodes and serves as a terminal.

[0003] Specifically, on the current collectors of the two outermost electrodes, a plurality of laminated sheets are placed, and the laminated sheets have an opening provided at the center thereof. By sealing the four sides of each laminated sheet and attaching the edge of the opening of the laminated sheet to the current collector using a sealing resin, the four sides of each of the bipolar electrodes and the electrolyte layer are sealed under reduced pressure. Summary of the Invention

[0004] With the laminated battery of JP 2004-134210 A, it is difficult to measure the internal pressure of the laminated battery after sealing under reduced pressure. Therefore, the present disclosure provides an electricity storage device capable of easily measuring the internal pressure after sealing under reduced pressure.

[0005] According to one aspect of the present disclosure, an electricity storage device includes: an electricity storage module having an electrode body and having a main surface and an outer peripheral surface perpendicular to the main surface; a structure having an outer surface and an inner surface further on the outer peripheral surface side than the outer surface, and arranged in a state facing the outer peripheral surface; and an outer body accommodating the electricity storage module and the structure. The outer body includes a laminated sheet body arranged to cover the outer surface. A sealed internal space is formed between the inner surface and the outer peripheral surface using the laminated sheet body. The internal space is evacuated to have a negative pressure with respect to the pressure of the external space of the electricity storage device. A through hole penetrating from the inner surface to the outer surface is formed in the structure.

[0006] According to such a configuration, when an external position corresponding to the through hole in the laminated sheet body is suctioned (specifically, vacuum suctioned), this position is pulled under a pressure equal to the pressure of the internal space. As a result, this position deforms outward. By checking the pressure when such a state change occurs by an inspector or the like, the pressure of the internal space of the electricity storage device can be known. Therefore, according to this electricity storage device, it is possible to easily measure the internal pressure of the internal space after sealing under reduced pressure of the electricity storage device.

[0007] The electrode body may be a stacked electrode body having a plurality of electrodes stacked in a first direction perpendicular to the main surface. The through-hole may extend in the first direction.

[0008] According to such a configuration, an inspector or the like can bring the suction part of the suction device into contact with the main surface side of the power storage module so that the stacked sheet body is sucked in the stacking direction of the electrodes in the stacked electrode body. Therefore, compared with the configuration of sucking from the outer peripheral surface side of the power storage module, the inspection can be more easily performed.

[0009] The structure body may have a base portion extending in the first direction in a side view of the power storage module, and a wall portion extending from the base portion in a second direction oriented toward the outer peripheral surface, the wall portion being parallel to the main surface. The through-hole may be formed in the wall portion.

[0010] According to such a configuration, the through-hole may extend in the first direction, and the internal space may be fixed by the structure body.

[0011] The structure body may have a box shape. According to this configuration, the internal space can be sufficiently fixed by the structure body. In addition, the stacked sheet body can be strengthened from the inside of the power storage device by the structure body.

[0012] According to this power storage device, the internal pressure after decompression sealing can be easily measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the drawings, in which the same reference numerals denote the same elements, and in which:

[0014] Figure 1 is a perspective view of a stacked battery;

[0015] Figure 2 is a sectional view taken along line II-II shown in Figure 1 ;

[0016] Figure 3 is a sectional view taken along line III-III shown in Figure 1 ;

[0017] Figure 4 is a perspective view of the structure body;

[0018] Figure 5 is a view for explaining a measurement technique of the internal pressure of the internal space in the stacked battery;

[0019] Figure 6A is a view for explaining a method of manufacturing the first stacked sheet portion;

[0020] Figure 6B is a view for explaining a method of manufacturing the first stacked sheet portion;

[0021] Figure 6C is a view for explaining a method of manufacturing the first laminated sheet portion;

[0022] Figure 6D is a view for explaining a method of manufacturing the first laminated sheet portion;

[0023] Figure 6E is a view for explaining a method of manufacturing the first laminated sheet portion;

[0024] Figure 6F is a view for explaining a method of manufacturing the first laminated sheet portion;

[0025] Figure 6G is a view for explaining a method of manufacturing the first laminated sheet portion;

[0026] Figure 7A is a view for explaining a method of manufacturing the laminated battery and the outer body of the power storage module;

[0027] Figure 7B is a view for explaining a method of manufacturing the laminated battery and the outer body of the power storage module;

[0028] Figure 7C is a view for explaining a method of manufacturing the laminated battery and the outer body of the power storage module;

[0029] Figure 7D is a view for explaining a method of manufacturing the laminated battery and the outer body of the power storage module; and

[0030] Figure 8 is a view showing a modification of the laminated battery. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that, for the embodiments described below, the same or common parts are given the same reference signs in the drawings, and their descriptions will not be repeated.

[0032] Hereinafter, as an example of the power storage device, a laminated battery will be described by way of example. The laminated battery is mounted on an electric vehicle, such as a hybrid electric vehicle that travels using power from at least one of a motor and an engine, or an electric vehicle that travels using driving power obtained from electric energy.

[0033] In addition, hereinafter, the stacking direction of the electrodes in the laminated battery is also referred to as the "DR3 direction". The lateral direction perpendicular to the stacking direction of the laminated battery is also referred to as the "DR1 direction". The longitudinal direction perpendicular to the stacking direction of the laminated battery is also referred to as the "DR2 direction". The DR1 direction, the DR2 direction, and the DR3 direction are perpendicular to each other.

[0034] Figure 1 is a perspective view of the stacked battery according to the present embodiment. Figure 2 is along Figure 1 the cross-sectional view taken along the line II-II shown. Figure 3 is along Figure 1 the cross-sectional view taken along the line III-III shown. Refer to Figures 1 to 3 to describe the stacked battery 100 according to the present embodiment.

[0035] As Figures 1 to 3 shown, the stacked battery 100 includes a power storage module 1, a structure body 60 ( Figure 3 ), and an outer body 20 that houses the power storage module 1 and the structure body 60. The power storage module 1 has a stacked electrode body 10 and a resin sealing body 40 obtained by stacking a plurality of electrodes (electrode plates 11) mentioned later in the stacking direction.

[0036] The power storage module 1 further has a first main surface 91, a second main surface 92 on the opposite side of the first main surface 91, and an outer 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 to each other. The first main surface 91 and the second main surface 92 are surfaces extending in the DR1 direction and the DR2 direction. The first main surface 91 is the surface that contacts the first conductive plate 18 mentioned later. The second main surface 92 is the surface that contacts the second conductive plate 19 mentioned later.

[0037] The outer peripheral surface 93 is a surface perpendicular to the first main surface 91 and the second main surface 92. In this example, the outer peripheral surface 93 is composed of four end surfaces 93a to 93d (refer to Figure 2 , Figure 3 , Figure 7A , Figure 7B , Figure 7C , Figure 7D ). Each of the end surfaces 93a - 93d is a side surface of the resin sealing body 40. In this example, each of the end surfaces 93a to 93d is a rectangular plane.

[0038] The outer body 20 is electrically connected to a terminal electrode of the stacked electrode body 10 mentioned later, and is arranged to be able to take out current to the outside in the stacking direction. The outer body 20 includes a first conductive plate 18, a second conductive plate 19, a first laminated sheet portion 21, a second laminated sheet portion 22, and a plurality of resin sheets 50. An example of the stacked battery 100 is a secondary battery such as a lithium-ion battery.

[0039] The stacked electrode body 10 includes a plurality of electrode plates 11, a plurality of separators 15, a positive terminal electrode 16, and a negative terminal electrode 17. The plurality of electrode plates 11, the positive terminal electrode 16, and the negative terminal electrode 17 are stacked in the stacking direction (Figure 2 and Figure 3 stacked in the DR3 direction in Figure 3 .

[0040] Each separator 15 is formed in a sheet shape. Examples of the separator 15 include a porous membrane made of a polyolefin-based resin such as polyethylene (PE) and polypropylene (PP), a woven or non-woven fabric made of polypropylene, methyl cellulose, etc. The separator 15 can be reinforced with a vinylidene fluoride resin compound.

[0041] A plurality of electrode plates 11 are provided between the positive terminal electrode 16 and the negative terminal electrode 17. An example of the electrode plate 11 is a bipolar electrode. The electrode plate 11 includes a current collector 12, a positive electrode layer 13, and a negative electrode layer 14.

[0042] For example, the current collector 12 may include 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). In addition, the current collector 12 may be a metal foil plated on the surface.

[0043] The current collector 12 has a first surface 12a on one side in the stacking direction and a second surface 12b on the other side in the stacking direction. On the first surface 12a, the negative electrode layer 14 is provided. On the second surface 12b, the positive electrode layer 13 is provided.

[0044] The positive terminal electrode 16 is located on one side in the stacking direction. The positive terminal electrode 16 includes a current collector 12 and a positive electrode layer 13. Specifically, in the positive terminal electrode 16, neither the negative electrode layer 14 nor the positive electrode layer 13 is 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. On the first surface 12a of the current collector 12 in the positive terminal electrode 16, a first conductive plate 18 is arranged. Note that the central portion (the portion other than the peripheral portion) of the first surface 12a of the current collector 12 in the positive 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 terminal electrode 16 and the upper surface of the resin seal 40.

[0045] The negative terminal electrode 17 is located on the other side in the stacking direction. The negative terminal electrode 17 includes a current collector 12 and a negative electrode layer 14. Specifically, in the negative terminal electrode 17, the negative electrode layer 14 is provided on the first surface 12a of the current collector 12, and neither the negative electrode layer 14 nor the positive electrode layer 13 is provided on the second surface 12b of the current collector 12. On the second surface 12b of the current collector 12 in the negative terminal electrode 17, a second conductive plate 19 is arranged. Note that the central portion (the portion other than the peripheral portion) of the second surface 12b of the current collector 12 in the negative 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 terminal electrode 17 and the lower surface of the resin sealing body 40.

[0046] The positive electrode layer 13 is formed by applying a positive electrode active material on the second surface 12b. For example, a positive electrode active material that can store and release charge carriers such as lithium ions can be used. Specifically, a positive electrode active material that can be used as the positive electrode active material of a lithium ion secondary battery can be used, such as a lithium ion composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, and a polyanion-based compound. In addition, two or more positive electrode active materials can be used together, and, for example, the positive electrode active material can include olivine lithium iron phosphate (LiFePO4).

[0047] The negative electrode layer 14 is formed by applying a negative electrode active material on the first surface 12a. As the negative electrode active material, for example, lithium, carbon, a metal compound, an element that can be alloyed with lithium or its compound, etc. can be used.

[0048] Note that in any of the plurality of electrode plates 11, the negative terminal electrode 17, and the positive terminal electrode 16, the peripheral portion of the current collector 12 is an unapplied area where neither the positive electrode layer 13 nor the negative electrode layer 14 is provided.

[0049] The resin sealing body 40 is provided to seal the periphery of the stacked electrode body 10. Specifically, the resin sealing body 40 seals the monomer space formed between two adjacent electrode plates 11. An electrolyte solution is injected into each monomer space. The resin sealing body 40 is formed by hardening a resin member such as a hot melt material, a thermoplastic resin, a thermosetting resin, a photocurable resin, etc. The resin sealing body 40 is provided in the aforementioned unapplied area.

[0050] The first conductive plate 18 and the second conductive plate 19 are arranged such that the laminated electrode body 10 is interposed therebetween in the lamination 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. By being arranged in contact with the first surface 12a, the first conductive plate 18 is electrically connected to the positive terminal electrode 16. By being electrically connected to the positive terminal electrode 16, the first conductive plate 18 serves as the positive terminal of the laminated battery 100.

[0051] 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. By being arranged in contact with the second surface 12b, the second conductive plate 19 is electrically connected to the negative terminal electrode 17. By being electrically connected to the negative terminal electrode 17, the second conductive plate 19 serves as the negative terminal of the laminated battery 100.

[0052] With the laminated battery 100, without using a tab for taking out current to the outside, current can be taken out from the power storage module 1 accommodated inside to the outside via the first conductive plate 18 serving as the positive terminal and the second conductive plate 19 serving as the negative terminal.

[0053] Each of the first conductive plate 18 and the second conductive plate 19 has a rectangular shape with a plurality of corner portions. The peripheries of the first conductive plate 18 and the second conductive plate 19 are located on the resin sealing body 40.

[0054] In this example, the first conductive plate 18 and the second conductive plate 19 are aluminum (Al) plates. However, the first conductive plate 18 and the second conductive plate 19 may include at least one selected from 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 a metal foil plated on the surface.

[0055] The first laminated sheet portion 21 is joined to the periphery of the first conductive plate 18. The first laminated sheet portion 21 is joined to the first conductive plate 18 in a state where the resin sheet 50 is interposed between the first laminated sheet portion 21 and the periphery of the first conductive plate 18. The second laminated sheet portion 22 is joined to the periphery of the second conductive plate 19. The second laminated sheet portion 22 is joined to the second conductive plate 19 in a state where the resin sheet 50 is interposed between the second laminated sheet portion 22 and the periphery of the second conductive plate 19.

[0056] In this example, the resin sheet 50 is formed of a resin material having insulating ability. 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 sealant film for insulation.

[0057] Specifically, each 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 interposed between the resin layer 51 and the resin layer 53.

[0058] The resin layers 51, 53 are sealant resin layers. Similarly, as shown in Figure 6B and Figure 6C in this embodiment, the resin layers 51, 53 are acid-modified PP (PPa) layers. The resin layer 51 is thermally welded to the first conductive plate 18. In this example, the resin layer 52 is a polypropylene (PP) layer.

[0059] Note that the resin types forming each of the resin layers 51 to 53 are not limited to the above resin types, and for example, heat-sealing resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene can be appropriately employed.

[0060] The central portions of the first conductive plate 18 and the second conductive plate 19 are exposed areas where the resin sheet 50, the first laminate sheet portion 21, or the second laminate sheet portion 22 is not coated. Through this exposed area, current can be directly taken out from the power storage module 1 accommodated inside to the outside.

[0061] The first laminate sheet portion 21 includes a plurality of first sheets 31 and a plurality of second sheets 32 (refer to Figure 2 , Figure 3 , Figure 6A , Figure 6B , Figure 6C , Figure 6D , Figure 6E , Figure 6F , Figure 6G ). The plurality of first sheets 31 and the plurality of second sheets 32 together 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 together cover the periphery of the second conductive plate 19.

[0062] Each first sheet 31 (refer to Figure 2 ) has a first metal layer 310 and sealant resin layers 311, 312. The first metal layer 310 has a sheet shape. In this example, also as mentioned later in Figure 6EAs shown, the first metal layer 310 is an aluminum foil (Al foil) layer. 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 permeability resistance, gas permeability resistance, and chemical resistance to the first sheet 31.

[0063] Sealant resin layers 311 and 312 are provided on two surfaces 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.

[0064] The sealant resin layers 311 and 312 are compatible with the resin sheet 50. In this example, the sealant resin layers 311 and 312 are made of polypropylene (PP). Not limited thereto, the sealant resin layers 311 and 312 can be made of heat-sealing resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene.

[0065] The sealant resin layers 311 and 312 serve as the sealing layers of the outer body 20. In addition, the sealant resin layers 311 and 312 also function as insulating layers and insulate the first laminated sheet portion 21 and the second laminated sheet portion 22 when the first laminated sheet portion 21 and the second laminated sheet portion 22 are joined.

[0066] Each second sheet 32 (refer to Figure 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 sequence from the inside of the laminated battery 100 toward the outside. The fourth resin layer 324 is the outermost layer of the second sheet 32.

[0067] In this example, as also mentioned later Figure 6F shown, the second metal layer 320 is an Al foil layer. The first resin layer 321 is an acid-modified PP (PPa) layer. The second resin layer 322 is a nylon layer. The third resin layer 323 is a polypropylene (PP) layer. The fourth resin layer 324 (the outermost layer) is a polyethylene terephthalate (PET) layer. 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.

[0068] 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 oriented inward (oriented toward the side where the laminated electrode body 10 is located), and the second main surface 320b is a surface oriented outward (oriented toward the opposite side of the side where the laminated electrode body 10 is located).

[0069] 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 can be greater than the thickness of the first metal layer 310. The thickness of the second metal layer 320 and the thickness of the first metal layer 310 can be made equal.

[0070] 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-sealing resins such as polyethylene, modified polyethylene, and modified polypropylene can also be used. Preferably, for the fourth resin layer 324, a resin material incompatible with the sealant resin layer 312 can be employed.

[0071] In the second sheet 32, a nylon layer (second resin layer 322) and a polyethylene terephthalate layer (fourth resin layer 324) overlap on the outer side of the second metal layer 320. Therefore, the combination of the multiple layers on the outer side of the second metal layer 320 in the second sheet 32 has higher strength than the combination of the two layers (first resin layer 321 and third resin layer 323) on the inner side of the second metal layer 320. Note that the term "high strength" means high rigidity or tensile strength. Thus, damage to the second metal layer 320 can be appropriately prevented when the second sheet 32 receives an external force such as a stab wound.

[0072] Now, the sealant resin layer 312 (refer to Figure 2 ) of the first sheet 31 is a polypropylene (PP) layer as described above. Therefore, the combination of the layers on the outer side of the second metal layer 320 of the second sheet 32 has higher 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 has higher strength than the sealant resin layer 312 of the first sheet 31. By increasing the strength of the second sheet 32, damage to the second sheet 32 can be appropriately prevented in the deep drawing described later.

[0073] The first laminated sheet portion 21 is obtained by deep drawing in a state of being joined to the first conductive plate 18. That is, a stretching process 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 that bends outward is provided at the lower opening end of the first laminated sheet portion 21.

[0074] The second laminated sheet portion 22 is obtained by deep drawing in a state of being joined to the second conductive plate 19. That is, similar to the first laminated sheet portion 21, a stretching process is also performed on the second laminated sheet portion 22. As a result, the second laminated sheet portion 22 has a shape that opens upward and downward. A flange portion 22f that bends outward is provided at the upper opening end of the second laminated sheet portion 22.

[0075] The first laminated sheet portion 21 and the second laminated sheet portion 22 have accommodation recesses 21c, 22c for accommodating the power storage module 1 inside. The accommodation recesses 21c, 22c cover a part of the first main surface 91, a part of the second main surface 92, and the outer peripheral surface 93 in the power storage module 1.

[0076] Specifically, the accommodation recesses 21c, 22c cover the peripheral portions of the upper surface and the lower surface of the power storage module 1, and the outer peripheral surface of the power storage module 1. Specifically, the accommodation recesses 21c, 22c cover the peripheral portions of the upper surface and the lower surface of the laminated electrode body 10 and the outer 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.

[0077] For example, the accommodation recesses 21c, 22c are constituted by portions formed on the first laminated sheet portion 21 and the second laminated sheet portion 22 through the aforementioned stretching process. Note that it is not limited to these portions, and the accommodation recesses 21c and 22c can be provided so as to be able to accommodate the laminated electrode body 10. In addition, although the case where the accommodation recesses are provided in both the first laminated sheet portion 21 and the second laminated sheet portion 22 has been exemplarily described above, the accommodation recess can be provided only in one of the first laminated sheet portion 21 and the second laminated sheet portion 22.

[0078] 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. Each resin sheet 50 has an inner edge portion 50i located on the central side of the laminated electrode body 10, and an outer edge portion 50c.

[0079] In order to ensure the insulation distance between both the first metal layer 310 included in the first sheet 31 and the second metal layer 320 included in the second sheet 32 and both the first conductive plate 18 and the second conductive plate 19, the inner edge portion 50i is further positioned on the central side of the laminated electrode body 10 compared with the inner end portions 31i, 32i.

[0080] 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, 32i are further positioned on the central side of the laminated electrode body 10 compared with the outer edge portions 18c, 19c.

[0081] The portions where both the first conductive plate 18 and the second conductive plate 19 overlap with the resin sheet 50 are welded. The bonding interface at the overlapping portion is sealed.

[0082] Although the outer edge portion 50c of the resin sheet 50 is positioned outside the outer edge portions 18c and 19c, it is not limited thereto, and the outer edge portion 50c may be flush with the outer edge portions 18c and 19c.

[0083] 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, the first conductive plate 18 and the second conductive plate 19 can be constrained to prevent short - circuiting via the first sheet 31 having the first metal layer 310 or the second sheet 32 having the second metal layer 320.

[0084] Next, the structure 60 will be described. As described above, the structure 60 is accommodated in the outer body 20. As Figure 3 shown, the structure 60 is arranged in a state facing the outer peripheral surface 93 (specifically, the end surfaces 93a and 93c) of the power storage module 1.

[0085] Figure 4 is a perspective view of the structure 60. In this example, as Figure 4 shown, the structure 60 has a box shape. The structure 60 is generally formed of resin. The structure 60 includes a base portion 61, and the base portion 61 extends in the DR3 direction in a side view of the power storage module 1 (refer to Figure 3 ).

[0086] The structure 60 further includes two wall portions 62 and 64 extending from the base portion 61 in the DR2 direction oriented toward the outer peripheral surface 93, and the two wall portions 62 and 64 are parallel to the first main surface 91 of the power storage module 1. The structure 60 further includes two wall portions 63 and 65 extending from the base portion 61 in the DR2 direction oriented toward the outer peripheral surface 93, and the two wall portions 63 and 65 are perpendicular to the first main surface 91.

[0087] The wall portions 62, 63, 64, and 65 standing up from the base portion 61 are continuous in this order. The wall portion 62 is positioned on the side of the first conductive plate 18. The wall portion 64 is positioned on the side of the second conductive plate 19. The base portion 61 and the wall portions 62, 63, 64, and 65 form a rectangular parallelepiped space 690 having an opening.

[0088] The structure 60 has an outer surface 60s and an inner surface 60t, and the inner surface 60t is further on the side of the outer peripheral surface 93 compared with the outer surface 60s. In the structure 60, a through - hole 60h is formed penetrating from the inner surface 60t to the outer surface 60s. Specifically, in this example, the through - hole 60h is formed in the wall portion 62. The through - hole 60h is formed at the central portion of the wall portion 62 along the DR3 direction.

[0089] The first laminated sheet portion 21 and the second laminated sheet portion 22 constituting the outer body 20 (refer to Figure 1is arranged to cover the outer surface 60s of the structure 60. Specifically, the second sheet 32 of the first laminated sheet portion 21 and the second laminated sheet portion 22 (see Figure 3 is arranged to cover the outer surface 60s of the structure 60. As Figure 3 shown, the second sheet 32 of the first laminated sheet portion 21 covers the open end of the through hole 60h on the outer surface 60s side.

[0090] Between the inner surface 60t, which is part of the base 61 in the structure 60, and the end face 93a of the power storage module 1, the second sheets 32 of the first laminated sheet portion 21 and the second laminated sheet portion 22 form a sealed internal space 800 as Figure 3 shown. The internal space 800 is evacuated to have a negative pressure with respect to the pressure of the external space of the laminated battery 100 (atmospheric pressure in this example). In this example, the internal space 800 is evacuated to about 1 kPa (kilopascal) in the initial state. The internal space 800 is in a low vacuum state by this vacuum pumping. In the case of the pressure difference resulting from this evacuation between the internal space 800 and the external space of the laminated battery 100, a binding force is applied to the laminated electrode body 10.

[0091] As described above, the laminated battery 100, as an example of a power storage device, includes a power storage module 1 having a laminated electrode body 10, and having a first main surface 91, a second main surface 92, and an outer peripheral surface 93 perpendicular to the first main surface 91 and the second main surface 92. As Figure 3 and Figure 4 shown, the laminated battery 100 further includes a structure 60 having an outer surface 60s and an inner surface 60t. The inner surface 60t is further on the outer peripheral surface 93 side compared to the outer surface 60s, and the structure 60 is arranged in a state facing the outer peripheral surface 93. As Figure 2 and Figure 3 shown, the laminated battery 100 further includes an outer body 20 that houses the power storage module 1 and the structure 60.

[0092] As Figure 3 shown, the outer body 20 further includes a first laminated sheet portion 21 and a second laminated sheet portion 22 arranged to cover the outer surface 60s. As Figure 3 shown, between the inner surface 60t and the outer peripheral surface 93, an internal space 800 sealed by the first laminated sheet portion 21 and the second laminated sheet portion 22 is formed. The internal space 800 is evacuated to have a negative pressure with respect to the pressure of the external space of the laminated battery 100. As Figure 3 and Figure 4 shown, in the structure 60, a through hole 60h is formed that penetrates from the inner surface 60t to the outer surface 60s.

[0093] Currently, there is also a problem that air (nitrogen, oxygen, etc.) invades from the outside of the laminated battery 100 into the internal space 800 of the laminated battery 100. For example, when there are some troubles in the welding of the first laminated sheet portion 21 and the second laminated sheet portion 22, air may invade the gap between the flange portion 21f and the flange portion 22f. Therefore, after manufacturing the laminated battery 100 and before transporting the laminated battery 100 or loading it into a vehicle, it is necessary to check the pressure (internal pressure) of the internal space 800.

[0094] Figure 5 It is a view for explaining a measurement technique of the internal pressure of the internal space 800 in the laminated battery 100. As Figure 5 shown, the internal pressure of the internal space 800 is measured by the 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 communicate with each other through the pipe 940. Note that in this example, the chamber does not mean the space itself, but means a member for forming the space.

[0095] 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 the shape of an inverted container. 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 has a ring shape. The O-ring 932 is attached to the open end by an adhesive or the like. A through hole 933 for inserting the pipe 940 into the chamber 930 is formed on the side surface of the main body 931.

[0096] When inspecting using 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, 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 in the plan view of the laminated battery 100, and the O-ring 932 is pressed against the fourth resin layer 324 of the second sheet 32. That is, 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 in the plan view of the laminated battery 100, 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 can be moved.

[0097] In this state, the inspector operates the suction device 910 to suck the air inside the chamber 930. The suction starts to reduce the pressure inside the chamber 930. The inspector can check the pressure inside the chamber 930 with the pressure gauge 920.

[0098] Suction is further carried out. When the pressure in the chamber 930 is lower than the pressure in the internal space 800 of the laminated battery 100, the second sheet 32 of the first laminated sheet portion 21 is pulled toward the chamber 930 side. Therefore, as Figure 5 shown, the second sheet 32 is in a state of being partially sucked into the chamber 930. That is, a state of bulging upward is presented from the position where the second sheet 32 covers the through-hole 60h. By checking the value of the pressure gauge 920 (the memory in this example) when this state change occurs, the inspector can know the pressure in the internal space 800 of the laminated battery 100. That is, according to the laminated battery 100, the internal pressure of the internal space 800 after the decompression sealing of the laminated battery 100 can be easily measured.

[0099] Since the pressure in the internal space 800 of the laminated battery 100 can be measured by using the above-described inspection device 900, the pressure in the internal space 800 can be measured even when vacuum suction is performed without putting the entire power storage device into the chamber. If vacuum suction is performed with the power storage device placed in the chamber, the following problem occurs: the constraint on the laminated electrode body 10 is released due to deformation of the conductors at the outermost layer (the conductors corresponding to the first conductive plate 18 and the second conductive plate 19), etc.

[0100] However, according to the laminated battery 100 of this example, it is not necessary to put the entire laminated battery 100 into a chamber. Therefore, the constraint on the laminated electrode body 10 is not released due to the measurement of the pressure in the internal space 800. Therefore, a high-quality laminated battery 100 can be provided.

[0101] In this example, as Figure 4 shown, the through-hole 60h extends in the DR3 direction. Therefore, the inspector presses the chamber 930 onto the second sheet 32 of the first laminated sheet portion 21 from above. Therefore, the inspection is easy. In addition, compared with the structure in which the through-hole 60h is formed in the base portion 61 (refer to Figure 8 ), this further enhances the flexibility of the arrangement piping 940 caused by its interval.

[0102] As Figure 4 shown, the through-hole 60h is formed in the wall portion 62. Therefore, the through-hole 60h can extend in the DR3 direction (lamination direction), and the internal space 800 can be ensured by the structure body 60. In addition, the open end of the through-hole 60h on the outer surface 60s side can be covered by the second sheet 32.

[0103] The structure body 60 has a box shape. Therefore, the internal space 800 can be sufficiently ensured by the structure body 60. In addition, the second sheet 32 can be strengthened from the inside of the laminated battery 100 by the structure body 60.

[0104] Figure 6A , Figure 6B , Figure 6C , Figure 6D , Figure 6E , Figure 6F and Figure 6G are views for explaining a method of manufacturing the first laminated sheet portion 21. As Figure 6A shown, an aluminum plate for the first conductive plate 18 is prepared. As Figure 6B shown, two resin sheets 50 are welded along two long sides of the aluminum plate. Next, as Figure 6C shown, two resin sheets 50 are welded along two short sides of the aluminum plate. The resin sheets 50 on the long sides and the resin sheets 50 on the short sides overlap at the four corners as Figure 6C shown.

[0105] As Figure 6D shown, two resin sheets 70 are welded to each of the two resin sheets 50 on the long sides. In this example, each resin sheet 70 has a layer structure equivalent to that of the resin sheet 50. The two resin sheets 70 on the right side in the figure are spaced apart from each other in the DR2 direction and extend in the DR1 direction. Similarly, the two resin sheets 70 on the left side in the figure are also spaced apart from each other in the DR2 direction and extend in the DR1 direction. The four resin sheets 70 are welded to the resin sheets 50 on the long sides in a state of protruding from the resin sheets 50 in a direction opposite to the aluminum plate.

[0106] As Figure 6E shown, a first sheet 31 is welded to the resin sheet 50 and the two resin sheets 70 on the right side in the figure. Similarly, a first sheet 31 is also welded to the resin sheet 50 and the two resin sheets 70 on the left side in the figure. Each first sheet extends in the DR2 direction. The first sheet is longer than the spacing distance between the resin sheets 70 in the DR2 direction.

[0107] As Figure 6F shown, a second sheet 32 is welded to the resin sheet 50 on the upper side in the figure, the two resin sheets 70 on the upper side in the figure, and the ends (the upper ends in the figure) of the two first sheets 31. The second sheet 32 has a U-shaped configuration. Similarly, a second sheet 32 is welded to the resin sheet 50 on the lower side in the figure, the two resin sheets 70 on the lower side in the figure, and the ends (the lower ends in the figure) of the two first sheets 31. The second sheets 32 are in a state of being spaced apart from each other and facing each other in the DR2 direction. Note that Figure 6F the middle portion of the first laminated sheet portion 21 shown is axisymmetric with respect to both the DR1 direction and the DR2 direction.

[0108] By performing a stretching process along the dashed line L on the middle portion, as Figure 6GThe first laminated sheet portion 21 is formed as shown. The flange portion 21f of the first laminated sheet portion 21 is formed by a stretching process.

[0109] Note that the first laminated sheet portion 21 and the second laminated sheet portion 22 have identical shapes. The second laminated sheet portion 22 is also manufactured by a method similar to that of the first laminated sheet portion 21. Therefore, the description of the method for manufacturing the second laminated sheet portion 22 will not be repeated here.

[0110] Figure 7A and Figure 7B are views for explaining the method of manufacturing the laminated battery 100, the structure body 60, and the outer body 20 of the power storage module 1. As Figure 7A and Figure 7B shown, the structure body 60 is mounted on one of the two short sides of the power storage module 1. The structure body 60 is mounted at a position facing the end face 93a that constitutes the outer peripheral surface 93 of the power storage module 1.

[0111] In this example, the laminated battery 100 further includes structure bodies 60A and 60B. The structure bodies 60A and 60B have structures and functions similar to those of the structure body 60. Through holes 60h are formed in the structure bodies 60A and 60B. The structure body 60A has a length smaller than that of the structure body 60 in the DR1 direction. The structure body 60A has a length larger than that of the structure body 60 in the DR1 direction. Like the structure body 60, the structure bodies 60A and 60B are accommodated in the outer body 20.

[0112] The structure body 60A is mounted on the same side as the structure body 60. Like the structure body 60, the structure body 60A is mounted such that the opening side faces the end face 93a. The structure body 60B is mounted on the short side opposite to the structure body 60. The structure body 60B is mounted at a position facing the end face 93c of the power storage module 1. Specifically, the structure body 60B is mounted such that the opening side faces the end face 93c. In the DR1 direction, the through holes 60h of the structure body 60, the through holes 60h of the structure body 60A, and the through holes 60h of the structure body 60B are located at different positions.

[0113] As Figure 7C shown, the power storage module 1 and the three structure bodies 60, 60A, and 60B are sandwiched between the first laminated sheet portion 21 and the second laminated sheet portion 22. Note that the second laminated sheet portion 22 is in a flipped state. Thereafter, the laminated battery 100 is completed by welding the first laminated sheet portion 21 and the second laminated sheet portion 22 together, as Figure 7D shown.

[0114] Note that, in order to make the position of the through hole 60h visually recognizable, the marks 990, 991, and 992 may be printed on the first laminated sheet portion 21. 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.

[0115] Note that the through hole 60h is not necessarily formed in the structures 60A and 60B. Any one of the structures 60, 60A, and 60B may be formed with a through hole 60h. In the case of a configuration in which the pressure in the internal space 800 is automatically inspected by the inspection device 900, the marks 990, 991, and 992 are not required.

[0116] Variant

[0117] (1) Figure 8 is a view showing a variant of the laminated battery 100. As Figure 8 shown, the laminated battery 100A is different from the laminated battery 100 in that it includes a structure 60Z instead of the structure 60.

[0118] The structure 60Z has a through hole 60h formed in the base portion 61 (refer to Figure 4 ), rather than in the wall portion 62. In this configuration, the chamber 930 of the inspection device 900 ( Figure 5 ) can be pressed against the side portion of the second sheet 32 so as to move relatively in the DR2 direction.

[0119] (2)The shape of the structure 60 is not limited to a box shape. The structure 60 may have a shape like an H-shaped steel extending in the DR2 direction. The structure 60 may have a shape having at least a base portion 61 and a wall portion 62. The shape of the base portion 61 is not limited to a rectangular parallelepiped shape. In order to reduce the weight, notches (through holes, etc.) may be formed in the base portion 61 and the wall portions 62 to 65.

[0120] The embodiments disclosed above are illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims, and all changes thereof are included in the spirit and scope of the claims and their equivalents.

Claims

1. An electric storage device, comprising: A power storage module having an electrode body and having a main surface and an outer peripheral surface perpendicular to the main surface; a structure having an outer surface and an inner surface, wherein the inner surface is further on the outer peripheral surface side than the outer surface, and the structure is arranged in a state facing the outer peripheral surface; and An outer body, the outer body accommodating the power storage module and the structure, wherein: The outer body comprises a laminated sheet body arranged to cover the outer surface; Between the inner surface and the outer peripheral surface, a sealed internal space is formed by the laminated sheet body; The internal space is evacuated so as to have a negative pressure relative to the pressure of the external space of the power storage device; and A through hole is formed in the structure body, penetrating from the inner surface to the outer surface.

2. The power storage device according to claim 1, wherein: The electrode body is a stacked electrode body having a plurality of electrodes stacked in a first direction perpendicular to the main surface; and The through hole extends in the first direction.

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

4. The power storage device according to claim 3, wherein: The structure has a box shape.

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