Power storage device and power storage system

Abstract

To provide a power storage device capable of continuing to apply appropriate restraining force to a laminated electrode body even when air enters an interior space of the power storage device from an exterior space of the power storage device.SOLUTION: A power storage device includes: a power storage module having a laminated electrode body; an outer sheath for accommodating the power storage module and forming an interior space sealed between the power storage module and the outer sheath; and a first piping for discharging gas contained in the interior space to the outside of the power storage device. The pressure in the interior space of the power storage device is maintained in a negative pressure against the pressure in the exterior space of the power storage device by a suction device which draws gas through the first piping.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a power storage device and a power storage system including a plurality of power storage devices.

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. As each laminate sheet, a polymer-metal composite film in which a heat-sealable resin film, a metal foil, and a rigid resin film are laminated in this order is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, due to the above-described reduced pressure, a pressure difference is generated between the internal space and the external space of the laminated battery. In Patent Document 1, a restraining force is applied to the laminated electrodes (laminated electrode body) by the pressure difference.

[0006] In a laminated battery as described in Patent Document 1, there is a risk that the pressure difference between the internal space and the external space of the laminated battery may decrease due to air intrusion from the joint of the laminate sheet. In this case, it becomes impossible to apply an appropriate restraining force to the laminated electrode body.

[0007] The present disclosure provides a power storage device capable of continuously applying an appropriate restraining force to a laminated electrode body even when air intrudes from the external space of the power storage device into the internal space thereof, and a power storage system including a plurality of such power storage devices.

Means for Solving the Problems

[0008] According to an aspect of the present disclosure, a power storage device includes a power storage module having a laminated electrode body, an exterior body that houses the power storage module and forms an internal space sealed between the exterior body and the power storage module, and a first pipe that discharges the gas contained in the internal space to the outside of the power storage device. The power storage device maintains the air pressure in the internal space such that the air pressure in the internal space becomes a negative pressure with respect to the air pressure in the external space of the power storage device by a suction device that sucks the gas through the first pipe.

[0009] According to such a configuration, even if air intrudes into the internal space, the air in the internal space is sucked by the first pipe and the suction device, so that the air pressure in the internal space does not become a negative pressure with respect to the air pressure in the external space. Therefore, even when air intrudes from the external space of the power storage device into the internal space of the power storage device, it is possible to continuously apply an appropriate restraining force to the laminated electrode body.

[0010] Preferably, the power storage device further includes a structure housed in the exterior body. The power storage module has a main surface and a peripheral surface perpendicular to the main surface. The structure has an outer surface and an inner surface on the peripheral surface side rather than the outer surface, and is disposed in a state of facing the peripheral surface. The exterior body includes a laminate sheet body disposed so as to cover the outer surface. The internal space is formed between the inner surface and the peripheral surface by being sealed by the laminate sheet body. A through hole penetrating from the outer surface to the inner surface is formed in the structure. The first pipe reaches the internal space through the through hole.

[0011] According to such a configuration, the air in the internal space can be sucked through the first pipe. Further, the structure can suppress the first pipe from being blocked inside the exterior body.

[0012] Preferably, the power storage device further includes a suction device. The suction device includes a pump that sucks the gas contained in the internal space through the first pipe, a control device that controls the operation of the pump, and a pressure gauge that measures the air pressure in the first pipe. The control device controls the operation of the pump so that the air pressure measured by the pressure gauge is equal to or lower than a threshold value lower than the air pressure in the external space.

[0013] According to such a configuration, it is possible to keep the air pressure in the internal space equal to or lower than a threshold value lower than the air pressure in the external space.

[0014] According to another aspect of the present disclosure, the power storage system includes a plurality of the above-described power storage devices. The power storage system further includes the above-described suction device. The suction device includes a pump, a first pipe of each power storage device, a second pipe that connects the pump and the first pipes, a control device that controls the operation of the pump, and a pressure gauge that measures the air pressure in the second pipe. The pump can suck the gas contained in the internal space of each power storage device through the first pipe and the second pipe. The control device controls the operation of the pump so that the air pressure measured by the pressure gauge is equal to or lower than a threshold value lower than the air pressure in the external space.

[0015] According to such a configuration, the internal spaces of the respective power storage devices can be simultaneously depressurized by one pump. Therefore, it is possible to keep the air pressure in the internal space of each power storage device equal to or lower than a threshold value lower than the air pressure in the external space.

Advantages of the Invention

[0016] According to the present disclosure, even when air enters the internal space of the power storage device from the external space of the power storage device, it is possible to continuously apply an appropriate restraining force to the laminated electrode body.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0018] 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.

[0019] Hereinafter, as an example of a power storage device, a stacked battery will be described as an example. The stacked 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.

[0020] Furthermore, hereinafter, the stacking direction of the electrodes in the stacked battery is also referred to as the "DR3 direction". The direction perpendicular to the stacking direction and the short side direction of the stacked battery are also referred to as the "DR1 direction". The direction perpendicular to the stacking direction and the long side direction of the stacked battery are also referred to as the "DR2 direction". The DR1 direction, the DR2 direction, and the DR3 direction are orthogonal to each other.

[0021] FIG. 1 is a perspective view of a stacked battery 100 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 stacked battery 100 according to the present embodiment will be described.

[0022] As shown in FIGS. 1 to 3, the stacked battery 100 includes a power storage module 1 having a stacked electrode body 10 in which a plurality of electrodes (electrode plates 11), which will be described later, are stacked in the stacking direction and a resin sealing body 40, a structure 60 (FIG. 3), an exterior body 20 that houses the power storage module 1 and the structure 60, a pipe 90, and a suction device 900. The exterior body 20 forms a sealed internal space 800 (see FIGS. 2 and 3) between it and the power storage module 1.

[0023] The suction device 900 includes a suction machine 910 and a pressure gauge 920. As shown in FIG. 3, the suction machine 910 incorporates a suction pump 911 and a control device 912.

[0024] The pipe 90 is used to discharge the gas contained in the internal space 800 of the stacked battery 100 to the outside of the stacked battery 100. The pipe 90 is connected to the suction machine 910 and the pressure gauge 920. The pipe 90 is connected to the suction machine 910. The pipe 90 is inserted into the internal space 800. The pipe 90 branches in the middle. The pipe 90 has three ends. The first end is connected to the suction machine 910. The second end is connected to the pressure gauge 920. The third end is inserted into the stacked battery 100.

[0025] 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, which will be described later. The second main surface 92 is a surface that contacts a second conductive plate 19, which will be described later.

[0026] The circumferential surface 93 is a surface 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. Each of the end surfaces 93a to 93d is a rectangular flat surface in this example.

[0027] The exterior body 20 is electrically connected to the terminal electrodes of the stacked electrode body 10 described later and is provided so as to be able to extract current to the outside from the stacking 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, a resin sheet 50, and a resin sheet 80. The stacked battery 100 is a secondary battery such as a lithium-ion battery, for example.

[0028] The stacked 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 stacked in the stacking direction (DR3 direction in FIGS. 2 and 3) with the separator 15 interposed therebetween.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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).

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In the laminated battery 100, it is possible to draw out the current to the outside from the power storage module 1 housed 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.

[0042] 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.

[0043] In this example, the first conductive plate 18 and the second conductive plate 19 are aluminum (Al) plates. 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). Further, the current collector 12 may be a metal foil with plating applied to its surface.

[0044] 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.

[0045] The resin sheet 50 adheres the first conductive plate 18 and the first laminate sheet portion 21. The resin sheet 50 adheres the second conductive plate 19 and the second laminate sheet portion 22. 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.

[0046] 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.

[0047] The resin layers 51, 53 are sealant resin layers. As also shown in states (B) and (C) of FIG. 5 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 a layer of polypropylene (PP) in this example.

[0048] 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 employed.

[0049] The resin sheet 80 is provided for insulation measures. The resin sheet 80 is provided to prevent short-circuiting of the outermost electrodes via the first and second metal layers 310 and 320 (Figs. 2 and 3) described later. Specifically, the resin sheet 80 prevents short-circuiting and liquid leakage between the first and second metal layers 310 and 320 and the first conductive plate 18. The resin sheet 80 prevents short-circuiting and liquid leakage between the first and second metal layers 310 and 320 and the second conductive plate 19.

[0050] The resin sheet 80 is formed of a resin material having insulating properties. The resin sheet 80 is formed of a resin material that can be welded to the resin sheet 50 and the first and second laminate sheet portions 21 and 22. Specifically, the resin sheet 80 is welded to the resin layer 53, the sealant resin layer 312 (Fig. 2) described later, and the fourth resin layer 324 (Fig. 3). The resin sheet 80 includes at least a layer of acid-modified PP (PPa). In this example, the resin sheet 80 has the same layer configuration as the resin sheet 50.

[0051] 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.

[0052] 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.

[0053] 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. 5 to be 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 permeability resistance, air permeability resistance, and chemical resistance to the first sheet 31.

[0054] 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.

[0055] 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. For example, heat-sealable resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene may be employed for the sealant resin layers 311 and 312.

[0056] 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 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.

[0057] 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, from the inside to the outside of the laminated battery 100, 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. The fourth resin layer 324 is the outermost layer in the second sheet 32.

[0058] In this example, as also shown in state (F) of FIG. 5 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.

[0059] 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 inner side (the side where the laminated electrode body 10 is located), and the second main surface 320b is a surface facing the outer side (the side opposite to the side where the laminated electrode body 10 is located).

[0060] The second metal layer 320 is not limited to 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 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 may be the same.

[0061] 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 employed. For the fourth resin layer 324, it is preferable to use a resin material that is incompatible with the sealant resin layer 312.

[0062] 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 has higher 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 high tensile strength. This can preferably prevent the second metal layer 320 from being damaged when the second sheet 32 receives an external force such as being pierced.

[0063] By the way, 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 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, it is possible to preferably prevent the second sheet 32 from being damaged during the deep drawing forming described later.

[0064] The first laminated sheet portion 21 is deep drawn in a state of being joined to the first conductive plate 18. That is, drawing processing 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.

[0065] The second laminated sheet portion 22 is deep drawn in a state of being joined to the second conductive plate 19. That is, similar to the first laminated sheet portion 21, drawing processing 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 bent outward is provided at the upper opening end of the second laminated sheet portion 22.

[0066] The first laminate sheet portion 21 and the second laminate sheet portion 22 are provided with accommodation recesses 21c and 22c for accommodating the power storage module 1 therein. By the accommodation recesses 21c and 22c, 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 are covered.

[0067] Specifically, by the accommodation recesses 21c and 22c, the peripheral portions of the upper surface and the lower surface of the power storage module 1, as well as the peripheral surface of the power storage module 1, are covered. Specifically, by the accommodation recesses 21c and 22c, the peripheral portions of the upper surface and the lower surface of the laminated electrode body 10, as well as the peripheral surface of the laminated electrode body 10, are covered. 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.

[0068] The accommodation recesses 21c and 22c are constituted by, for example, portions formed by performing the above-described drawing process on the first laminate sheet portion 21 and the second laminate sheet portion 22. Note that the accommodation 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. Further, in the above description, the case where the accommodation recesses are provided in both the first laminate sheet portion 21 and the second laminate sheet portion 22 is exemplified, but the accommodation recess may be provided only in one of the first laminate sheet portion 21 and the second laminate sheet portion 22.

[0069] 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.

[0070] In order to ensure the 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 closer to the center of the laminated electrode body 10 than the inner ends 31i, 32i.

[0071] The first conductive plate 18 has an outer edge portion 18c. The second conductive plate 19 has an outer edge portion 19c. The inner ends 31i, 32i are located closer to the center of the laminated electrode body 10 than the outer edge portions 18c, 19c.

[0072] The portions where the first conductive plate 18 and the second conductive plate 19 overlap with the resin sheet 50 are welded. The joint interface of the overlapping portions is sealed.

[0073] The outer edge portion 50c of the resin sheet 50 is located outside the outer edge portions 18c, 19c, but is not limited thereto, and the outer edge portion 50c and the outer edge portions 18c, 19c may be flush.

[0074] 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.

[0075] 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.

[0076] 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 portion 61 extending in the DR3 direction in a side view of the power storage module 1 (see FIG. 3).

[0077] The structure 60 further includes two wall portions 62 and 64 that extend from the base portion 61 in the DR2 direction parallel to the first main surface 91 of the power storage module 1 and toward the circumferential surface 93. The structure 60 further includes two wall portions 63 and 65 that extend from the base portion 61 in the DR2 direction perpendicular to the first main surface 91 and toward the circumferential surface 93.

[0078] Each of the wall portions 62, 63, 64, and 65 rising from the base portion 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 portion 61 and the wall portions 62, 63, 64, and 65 form a rectangular parallelepiped-shaped space 690 having an opening.

[0079] The structure 60 has an outer surface 60s and an inner surface 60t on the circumferential surface 93 side of 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 base portion 61. The through hole 60h is formed in the central portion of the base portion 61 in the DR2 direction.

[0080] 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.

[0081] An internal space 800 (FIG. 3) sealed as described above is formed between the inner surface 60t of the portion of the base portion 61 in the structure 60 and the end surface 93a of the power storage module 1 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 (atmospheric pressure in this example) of the external space of the laminated battery 100. In this example, the internal space 800 is depressurized to about 1 kPa (kilopascal) in the initial state. The internal space 800 is in a low vacuum state by evacuation. The pressure (atmospheric pressure) difference between the internal space 800 of the laminated battery 100 and the external space generated by such depressurization applies a restraining force to the laminated electrode body 10.

[0082] As shown in FIG. 3, the pipe 90 is passed through the through hole 60h. In this example, the tip of the pipe 90 reaches the internal space 800. The outer peripheral surface of the pipe 90 is in contact with the wall surface of the through hole 60h. A part of the pipe 90 is sandwiched between the second sheet 32 of the first laminate sheet portion 21 and the second sheet 32 of the second laminate sheet portion 22. The innermost third resin layer 323 of each second sheet 32 is welded to the outer peripheral surface of the pipe 90.

[0083] The suction device 910 sucks the air in the internal space 800 of the laminated battery 100 through the pipe 90. The pressure gauge 920 measures the air pressure in the internal space 800 of the laminated battery 100 by measuring the air pressure inside the pipe 90. The pressure gauge 920 notifies the measured air pressure to the suction device 910 through a signal line (not shown).

[0084] The control device 912 controls the suction pump 911. The control device 912 controls the operation of the suction pump 911 based on a program stored in a memory (not shown). The control device 912 receives the value of the air pressure measured by the pressure gauge 920 from the pressure gauge 920.

[0085] When the value of the air pressure exceeds the threshold Th1, the control device 912 operates the suction pump 911. When the value of the air pressure becomes equal to or lower than the threshold Th2, which is lower than the threshold Th1, the control device 912 stops the suction pump 911. In this way, the control device 912 controls the operation of the suction pump 911 so that the value (hereinafter, P) indicated by the pressure gauge 920 falls within a predetermined range (threshold Th1 ≥ P ≥ threshold Th2). The threshold Th1 is a value (for example, 5 kPa) that is sufficiently lower than the atmospheric pressure (about 101.325 kPa). The threshold Th2 is, for example, 1 kPa.

[0086] As described above, the laminated battery 100 includes a power storage module 1 having a laminated electrode body 10, an exterior body 20 that houses the power storage module 1 and forms an internal space 800 sealed between the exterior body 20 and the power storage module 1, and a pipe 90 that discharges the gas contained in the internal space 800 to the outside of the laminated battery 100. In the laminated battery 100, the air pressure in the internal space 800 is maintained such that it is negative pressure with respect to the air pressure in the external space of the laminated battery 100 by a suction device 900 that suctions the gas through the pipe 90.

[0087] By the way, there is a possibility that air (such as nitrogen and oxygen) from the outside of 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.

[0088] However, in the laminated battery 100, even if air enters the internal space 800, the air in the internal space 800 is suctioned by the pipe 90 and the suction device 900, so that the air pressure in the internal space 800 does not become negative pressure with respect to the air pressure in the external space. Therefore, even if air from the outside space of the laminated battery 100 enters the internal space 800 of the laminated battery 100, it is possible to continuously apply an appropriate restraining force to the laminated electrode body 10.

[0089] Specifically, focusing on the first main surface 91 out of the first main surface 91 and the second main surface 92, the laminated battery 100 has the following configuration. The power storage module 1 has the first main surface 91 and a peripheral surface 93 perpendicular to the first main surface 91. As shown in FIG. 3, the laminated battery 100 further includes a structure 60 housed in the exterior body 20. As shown in FIG. 4, 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, and is arranged in a state of facing the peripheral surface 93. The exterior body 20 further includes a second sheet 32 arranged to cover the outer surface 60s. The internal space 800 is formed between the inner surface 60t and the peripheral surface 93 by being sealed by the second sheet 32. A through hole 60h penetrating from the outer surface 60s to the inner surface 60t is formed in the structure 60. The pipe 90 reaches the internal space 800 through the through hole 60h.

[0090] According to such a configuration, the air in the internal space 800 can be sucked through the pipe 90. Further, the structure 60 can suppress the pipe 90 from being blocked in the exterior body 20.

[0091] More specifically, the laminated battery 100 includes a suction device 900. The suction device 900 has a suction pump 911 that sucks the gas contained in the internal space 800 through the pipe 90, a control device 912 that controls the operation of the suction pump 911, and a pressure gauge 920 that measures the air pressure in the pipe 940. The control device 912 controls the operation of the suction pump 911 so that the air pressure measured by the pressure gauge 920 is equal to or lower than a threshold value Th1 that is at least lower than the air pressure in the external space. According to such a configuration, it is possible to keep the air pressure in the internal space 800 equal to or lower than the threshold value Th1 that is lower than the air pressure in the external space.

[0092] FIG. 5 is a diagram for explaining a method of manufacturing the first laminate sheet portion 21. As shown in state (A) of FIG. 5, an aluminum plate to be the first conductive plate 18 is prepared. As shown in state (B), two resin sheets 50 are welded along two long sides of the aluminum plate. Next, as shown in state (C), two resin sheets 50 are welded along 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).

[0093] As shown in state (D), two resin sheets 70 are welded to each of the two resin sheets 50 on the long side. In this example, each resin sheet 70 has the same layer structure as the resin sheet 50. 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.

[0094] As shown in state (E), one first sheet 31 is welded to the resin sheet 50 and the two resin sheets 70 on the right side of the figure. Similarly, one first sheet 31 is also welded to the resin sheet 50 and the two resin sheets 70 on the left side of the figure. 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.

[0095] 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 of 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 of the figure). The second sheets 32 are spaced apart from each other and are in a state of facing each other in the DR2 direction. Note that the intermediate body of the first laminate sheet portion 21 shown as state (F) is line-symmetric in each of the DR1 direction and the DR2 direction.

[0096] By performing a drawing process on the intermediate body 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.

[0097] 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.

[0098] FIG. 6 is a diagram for explaining a method of manufacturing the laminated battery 100 using the power storage module 1 and the exterior body 20. As shown in states (A) and (B) of FIG. 6, 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.

[0099] 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. However, through holes 60h are not formed in the structures 60A and 60B. The structure 60A is shorter in length in the DR1 direction than the structure 60. The structure 60B is longer in length in the DR1 direction than the structure 60. The structures 60A and 60B are housed in the exterior body 20 in the same manner as the structure 60.

[0100] 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.

[0101] As shown in the state (C), the pipe 90 is passed through the through hole 60h of the structure 60. Further, 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, as shown in the state (D), the laminated battery 100 is completed.

[0102] <Modification Example> In the above, the configuration in which the laminated battery 100 includes the pipe 90 and the suction device 900 has been described. Hereinafter, a configuration in which a plurality of laminated batteries 100 share a suction device will be described.

[0103] FIG. 7 is a diagram for explaining the power storage system SYS. As shown in FIG. 7, the power storage system SYS includes a plurality of laminated batteries 100 and a suction device 900A.

[0104] The suction device 900A includes a suction machine 910, a pressure gauge 920A, a pipe 950, and a plurality of valves 960.

[0105] The pipe 950 connects the pipe 90 of the stacked battery 100 and the suction pump 911 of the suction device 900. The pipe 950 has one main pipe 951 and a plurality of branch pipes 952. Each branch pipe 952 is connected to the main pipe 951. The suction pump 911 is connected to the main pipe 951. Each branch pipe 952 is connected to a different valve 960. Each valve 960 is connected to a different pipe 90. One valve 960 connects one pipe 90 and one branch pipe 952.

[0106] The pressure gauge 920A measures the air pressure in the pipe 950. The pressure gauge 920A measures the air pressure in the main pipe 951. When each valve 960 is in the open state, the pressure gauge 920A will measure the average air pressure in the internal spaces 800 of the plurality of stacked batteries 100.

[0107] The suction pump 911 can suck the gas contained in the internal space 800 of each stacked battery 100 through each pipe 90 and the pipe 950. Specifically, when each valve 960 is in the open state, the suction pump 911 can suck the gas contained in each internal space 800.

[0108] In this example, the control device 912 controls the operation of the suction pump 911 so that the air pressure measured by the pressure gauge 920A is at least lower than the threshold Th1 of the air pressure in the external space. Specifically, when the value of the air pressure measured by the pressure gauge 920A exceeds the threshold Th1, the control device 912 operates the suction pump 911. When the value of the air pressure is lower than the threshold Th2 which is lower than the threshold Th1, the control device 912 stops the suction pump 911. In this way, the control device 912 controls the operation of the suction pump 911 so that the value P indicated by the pressure gauge 920A falls within a predetermined range (threshold Th1 ≥ P ≥ threshold Th2).

[0109] According to such a configuration, one suction pump 911 can simultaneously decompress the internal spaces 800 of each stacked battery 100. Therefore, it is possible to keep the air pressure in the internal space 800 of each stacked battery 100 below the threshold Th1 which is lower than the air pressure in the external space.

[0110] Each valve 960 may be configured to automatically open and close based on an instruction from the control device 912. In the case of such a configuration, the control device 912 controls the opening and closing of each valve so that only one of the plurality of valves 960 is sequentially opened. The control device 912 controls the operation of the suction pump 911 so that the air pressure in the internal space 800 measured by the pressure gauge 920A is equal to or lower than the threshold value Th1. According to such a configuration, the air pressure in each internal space 800 can be individually measured by the pressure gauge 920A, and the air pressure in each internal space 800 can be individually made equal to or lower than the threshold value Th1.

[0111] As described above, the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

Description of Reference Numerals

[0112] 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 part, 19 Second conductive plate, 20 Exterior body, 21 First laminate sheet part, 22 Second laminate sheet part, 21c, 22c Accommodation recess, 21f, 22f Flange part, 31 First sheet, 31i, 32i Inner end part, 32 Second sheet, 40 Resin sealing body, 50, 70, 80 Resin sheet, 50i Inner edge part, 51, 52, 53 Resin layer, 60, 60A, 60B Structure, 60h Through hole, 60s Outer surface, 60t Inner surface, 61 Base part, 62, 63, 64, 65 Wall part, 90, 950 Pipe, 91, 320a First main surface, 92, 320b Second main surface, 93 Peripheral surface, 93a, 93c, 93d End surface, 100 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, 900A Suction device, 910 Suction machine, 911 Suction pump, 912 Control device, 920, 920A Pressure gauge, 951 Main pipe, 952 Branch pipe, 960 Valve, L Virtual line, SYS Energy storage system.

Claims

1. A power storage device comprising: a power storage module having a laminated electrode body; an exterior body that houses the power storage module and forms an internal space sealed between the power storage module; and a first pipe that discharges gas contained in the internal space to the outside of the power storage device. The power storage device is a power storage device in which the air pressure in the internal space is maintained such that the air pressure in the internal space becomes a negative pressure with respect to the air pressure in the external space of the power storage device by a suction device that sucks the gas through the first pipe.

2. The power storage device further comprises a structure housed in the exterior body. The power storage module has a main surface and a peripheral surface perpendicular to the main surface. The structure has an outer surface and an inner surface on the peripheral surface side rather than the outer surface, and is arranged in a state of facing the peripheral surface. The exterior body includes a laminate sheet body arranged to cover the outer surface. The internal space is formed between the inner surface and the peripheral surface by being sealed by the laminate sheet body. A through hole penetrating from the outer surface to the inner surface is formed in the structure. The first pipe reaches the internal space through the through hole. The power storage device according to claim 1.

3. Further comprising the suction device, The suction device includes a pump that sucks the gas contained in the internal space through the first pipe, a control device that controls the operation of the pump, and a pressure gauge that measures the air pressure in the first pipe. The control device controls the operation of the pump such that the air pressure measured by the pressure gauge is equal to or lower than a threshold value lower than the air pressure in the external space. The power storage device according to claim 1 or 2.

4. A power storage system comprising a plurality of the power storage devices according to claim 1 or 2, further comprising the suction device, The suction device includes a pump, a second pipe that connects the first pipe of each power storage device and the pump, a control device that controls the operation of the pump, and a pressure gauge that measures the air pressure in the second pipe. The pump is capable of sucking the gas contained in the internal space of each power storage device through each first pipe and the second pipe. The control device controls the operation of the pump such that the air pressure measured by the pressure gauge is equal to or lower than a threshold value lower than the air pressure in the external space. The power storage system.

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