Electricity storage device and electricity storage system

Abstract

The invention relates to a power storage device and a power storage system. A power storage device includes: a power storage module having stacked electrode bodies; an outer body accommodating the power storage module, and forming a sealed internal space between the outer body and the power storage module; and a first pipe that discharges the gas contained in the internal space to the outside of the electricity storage device. The air pressure in the internal space of the electricity storage device is maintained at a negative pressure with respect to the air pressure in the external space of the electricity storage device by a suction device that sucks air through the first piping.

Description

Technical Field

[0001] The present disclosure relates to an electricity storage device and an electricity storage system including a plurality of electricity storage devices. Background Art

[0002] To date, various electricity storage devices have been known. Japanese Unexamined Patent Application Publication No. 2004-134210 (JP2004-134210 A) discloses a bipolar stacked battery as an example of an electricity storage device. In the stacked battery, sheet-like electrodes are stacked across an electrolyte layer. In the stacked battery, the electrodes are stacked in the outermost layer of the stack such that the current collectors included in the electrodes are exposed to the outside of the battery in the stacking direction of the electrodes and serve as terminals.

[0003] Specifically, each of the current collectors of the two electrodes in the outermost layer is covered with a laminated sheet in which an opening is provided at the center. The four edges of each laminated sheet are sealed, and the edge of the opening of each laminated sheet is attached to the current collector by a sealing resin. As a result, the four edges of the bipolar electrode and the electrolyte layer are depressurized and hermetically sealed. As each laminated sheet, a polymer metal composite film is used in which a heat-melting resin film, a metal foil, and a rigid resin film are stacked in the above order. Summary of the Invention

[0004] In JP 2004-134210 A, a pressure difference is generated between the internal space and the external space of the stacked battery by the above-described depressurization. In JP 2004-134210 A, a binding force is applied to the stacked electrodes (stacked electrode body) by the pressure difference.

[0005] In a stacked battery such as that described in JP 2004-134210 A, there is a risk that the pressure difference between the internal space and the external space of the stacked battery decreases due to air entering the joint portion of the laminated sheet. In this case, an appropriate binding force cannot be applied to the stacked electrode body.

[0006] The present disclosure provides an electricity storage device and an electricity storage system including a plurality of electricity storage devices, in which the electricity storage device can continue to apply an appropriate binding force to the stacked electrode body even when air enters the internal space of the electricity storage device from the external space.

[0007] According to one aspect of the present disclosure, an electricity storage device includes: an electricity storage module having stacked electrode bodies; an outer body that houses the electricity storage module and forms a sealed internal space between the outer body and the electricity storage module; and a first pipe that discharges gas contained in the internal space to the outside of the electricity storage device. By a suction device that sucks gas via the first pipe, the air pressure in the internal space of the electricity storage device is maintained at a negative pressure relative to the air pressure in the external space of the electricity storage device.

[0008] According to this configuration, even when air enters the internal space, the air in the internal space is sucked by the first pipe and the suction device, so the air pressure in the internal space does not become negative relative to the air pressure in the external space. Therefore, even when air enters the internal space of the electricity storage device from the external space, an appropriate binding force can continue to be applied to the stacked electrode bodies.

[0009] The electricity storage device may further include a structure housed in the outer body. The electricity storage module has a main surface and a peripheral surface perpendicular to the main surface. The structure has an outer front surface and an inner front surface on the peripheral surface side of the outer front surface, and is disposed in a state facing the peripheral surface. The outer body includes a laminated sheet body that is disposed to cover the outer front surface. The internal space is formed between the inner front surface and the peripheral surface by being sealed by the laminated sheet body. A through hole passing through the structure from the outer front surface to the inner front surface is formed in the structure. The first pipe reaches the internal space via the through hole.

[0010] According to this configuration, the air in the internal space can be sucked via the first pipe. The situation where the first pipe is closed in the outer body can be reduced by the structure.

[0011] The electricity storage device may further include a suction device. The suction device includes: a pump that sucks gas contained in the internal space via 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 becomes equal to or less than a threshold value lower than the air pressure in the external space.

[0012] According to this configuration, the air pressure in the internal space can be maintained at equal to or less than a threshold value lower than the air pressure in the external space.

[0013] According to another aspect of the present disclosure, an electricity storage system includes a plurality of the above-described electricity storage devices. The electricity storage system further includes the suction device as described above. The suction device includes: a pump; a second pipe that connects the first pipe of each electricity storage device and the pump to each other; 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 electricity storage device via the 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 becomes equal to or less than a threshold value lower than the air pressure in the external space.

[0014] According to this configuration, the internal space of each electricity storage device can be depressurized simultaneously by one suction pump. Therefore, the air pressure in the internal space of each electricity storage device can be maintained equal to or less than a threshold value lower than the air pressure in the external space.

[0015] According to the present disclosure, even when air enters the internal space of the electricity storage device from the external space, it is possible to continue to apply an appropriate binding force to the stacked electrode bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Hereinafter, the 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:

[0017] Figure 1 is a perspective view of a stacked battery;

[0018] Figure 2 is a cross-sectional view taken along line II-II shown in Figure 1 ;

[0019] Figure 3 is a cross-sectional view taken along line III-III shown in Figure 1 ;

[0020] Figure 4 is a perspective view of a structure;

[0021] Figure 5A is a view for describing a method of manufacturing a first laminated sheet portion;

[0022] Figure 5B is a view for describing a method of manufacturing a first laminated sheet portion;

[0023] Figure 5C is a view for describing a method of manufacturing a first laminated sheet portion;

[0024] Figure 5D is a view for describing a method of manufacturing a first laminated sheet portion;

[0025] Figure 5EIt is a diagram for describing a method of manufacturing a first laminated sheet portion;

[0026] Figure 5F It is a diagram for describing a method of manufacturing a first laminated sheet portion;

[0027] Figure 5G It is a diagram for describing a method of manufacturing a first laminated sheet portion;

[0028] Figure 6A It is a diagram for describing a method of manufacturing a stacked battery by a power storage module and an outer body;

[0029] Figure 6B It is a diagram for describing a method of manufacturing a stacked battery by a power storage module and an outer body;

[0030] Figure 6C It is a diagram for describing a method of manufacturing a stacked battery by a power storage module and an outer body;

[0031] Figure 6D It is a diagram for describing a method of manufacturing a stacked battery by a power storage module and an outer body; and

[0032] Figure 7 It is a diagram for describing a power storage system. Detailed Description of the Invention

[0033] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated.

[0034] As an example of the power storage device, a stacked battery will be described below as an example. The stacked battery is installed in an electric vehicle, such as a hybrid electric vehicle that travels using the power of at least one of a motor and an engine, and an electric vehicle that travels by a driving force obtained from electric energy.

[0035] The stacking direction of the electrodes in the stacked battery is also referred to as the "DR3 direction" hereinafter. The direction perpendicular to the stacking direction and being the short side direction of the stacked battery is also referred to as the "DR1 direction". The direction perpendicular to the stacking direction and being the longitudinal direction of the stacked battery is also referred to as the "DR2 direction". The DR1 direction, the DR2 direction, and the DR3 direction are orthogonal to each other.

[0036] Figure 1 It is a perspective view of a stacked battery 100 according to an embodiment of the present invention. Figure 2 It is along Figure 1 the cross-sectional view taken along line II-II shown. Figure 3 It is along Figure 1 the cross-sectional view taken along line III-III shown. Refer to Figures 1 to 3, which describes the stacked battery 100 according to this embodiment.

[0037] As Figures 1 to 3 shown, the stacked battery 100 includes a power storage module 1 having a resin seal 40 and stacked electrode bodies 10 (wherein a plurality of electrodes (electrode plates 11), which will be described later, are stacked in the stacking direction), a structure body 60 ( Figure 3 ), an outer body 20 that houses the power storage module 1 and the structure body 60, a pipe 90, and a suction device 900. The outer body 20 forms a sealed internal space 800 between the outer body 20 and the power storage module 1 (see Figure 2 and Figure 3 ).

[0038] The suction device 900 has a suction machine 910 and a pressure gauge 920. As Figure 3 shown, the suction machine 910 has a built-in suction pump 911 and a control device 912.

[0039] 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.

[0040] The power storage module 1 also has a first main surface 91, a second main surface 92 on the side 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 to each other. 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 the surface that contacts the first conductive plate 18, which will be described later. The second main surface 92 is the surface that contacts the second conductive plate 19, which will be described later.

[0041] The peripheral surface 93 is a surface perpendicular to the first main surface 91 and the second main surface 92. In this example, the peripheral surface 93 is constructed by four end surfaces 93a to 93d (see Figure 2 , Figure 3 and Figure 7 ). Each of the end surfaces 93a to 93d is a side surface of the resin seal 40. In this example, each of the end surfaces 93a to 93d is a flat surface having a rectangular shape.

[0042] The outer body 20 is electrically connected to the terminal electrodes of the stacked electrode body 10 described later, and is arranged such that current can be led 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, a resin sheet 50, and a resin sheet 80. The stacked battery 100 is a secondary battery, such as a lithium-ion battery.

[0043] 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 via the separators 15 in the stacking direction ( Figure 2 and Figure 3 the DR3 direction in

[0044] The separator 15 is formed in a sheet-like manner. Examples of the separator 15 include a porous film formed of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), and a woven or non-woven fabric formed of polypropylene, methyl cellulose, etc. The separator 15 can be reinforced with a vinylidene fluoride resin compound.

[0045] The plurality of electrode plates 11 are disposed between the positive terminal electrode 16 and the negative 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.

[0046] The current collector 12 may contain at least one type selected from the group consisting of, for example, aluminum (Al), stainless steel, nickel (Ni), chromium (Cr), platinum (Pt), niobium (Nb), iron (Fe), titanium (Ti), and zinc (Zn). The current collector 12 can be obtained by applying an electroplating process to the front surface of a metal foil.

[0047] 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. The negative electrode layer 14 is disposed on the first surface 12a. The positive electrode layer 13 is disposed on the second surface 12b.

[0048] 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, the negative electrode layer 14 and the positive electrode layer 13 are not disposed on the first surface 12a of the current collector 12, and the positive electrode layer 13 is disposed on the second surface 12b of the current collector 12. The first conductive plate 18 is disposed on the first surface 12a of the current collector 12 in the positive terminal electrode 16. 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.

[0049] 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 the negative electrode layer 14 and the positive electrode layer 13 are not provided on the second surface 12b of the current collector 12. The second conductive plate 19 is provided on the second surface 12b of the current collector 12 in the negative terminal electrode 17. 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.

[0050] The positive electrode layer 13 is formed by applying a positive electrode active material to the second surface 12b. For example, as the positive electrode active material, a material capable of blocking and releasing charge carriers (such as lithium ions) can be used. 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 compound, and a material capable of being used as a positive electrode active material of a lithium-ion secondary battery can be used. For example, two or more types of positive electrode active materials can be used together, and the positive electrode active material can contain olivine-type lithium iron phosphate (LiFePO 4 )

[0051] The negative electrode layer 14 is formed by applying a negative electrode active material to the first surface 12a. As the negative electrode active material, for example, lithium, carbon, metal compounds, elements that can be alloyed with lithium, and their compounds can be used.

[0052] In all 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 uncoated area where the positive electrode layer 13 and the negative electrode layer 14 are not provided.

[0053] The resin sealing body 40 is provided to seal the outer periphery of the stacked electrode body 10. Specifically, the resin sealing body 40 seals the battery space formed between two adjacent electrode plates 11. An electrolytic solution is injected into the battery space. The resin sealing body 40 is formed by curing a resin member such as a hot melt member, a thermoplastic resin, or a photocurable resin. The resin sealing body 40 is provided on the above-mentioned uncoated area.

[0054] The first conductive plate 18 and the second conductive plate 19 are arranged to sandwich the stacked 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. In other words, the first conductive plate 18 is disposed on the first major 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 arranged to abut against the first surface 12a. The first conductive plate 18 serves as the positive terminal of the stacked battery 100 by being electrically connected to the positive terminal electrode 16.

[0055] The second conductive plate 19 is disposed on the second surface 12b of the current collector 12 included in the negative terminal electrode 17. In other words, the second conductive plate 19 is disposed on the second major 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 arranged to abut against the second surface 12b. The second conductive plate 19 serves as the negative terminal of the stacked battery 100 by being electrically connected to the negative terminal electrode 17.

[0056] In the stacked battery 100, current can be taken out from the internally accommodated power storage module 1 via the first conductive plate 18 serving as the positive terminal and the second conductive plate 19 serving as the negative terminal, without using a tab for taking out current externally.

[0057] The first conductive plate 18 and the second conductive plate 19 have 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.

[0058] In this example, the first conductive plate 18 and the second conductive plate 19 are aluminum (Al) plates. The first conductive plate 18 and the second conductive plate 19 are not limited thereto, and 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). The current collector 12 can be obtained by applying an electroplating process to the front surface of a metal foil.

[0059] The first laminate sheet portion 21 is joined to the periphery of the first conductive plate 18. The first laminate sheet portion 21 is joined to the first conductive plate 18 in a state where the resin sheet 50 is interposed between the first laminate sheet portion 21 and the periphery of the first conductive plate 18. The second laminate sheet portion 22 is joined to the periphery of the second conductive plate 19. The second laminate sheet portion 22 is joined to the second conductive plate 19 in a state where the resin sheet 50 is interposed between the second laminate sheet portion 22 and the periphery of the second conductive plate 19.

[0060] The resin sheet 50 adheres the first conductive plate 18 and the first laminated sheet portion 21 to each other. The resin sheet 50 adheres the second conductive plate 19 and the second laminated sheet portion 22 to each other. 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 an insulating sealant film.

[0061] Specifically, the resin sheet 50 has resin layers 51, 52, 53. The resin layer 51 is the layer on the inner side. The resin layer 53 is the layer on the outer side. The resin layer 52 is sandwiched between the resin layer 51 and the resin layer 53.

[0062] The resin layers 51, 53 are sealant resin layers. Also as described later Figure 5B and Figure 5C as shown in, in this example, 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.

[0063] The type of resin constituting each of the resin layers 51 to 53 is not limited to the above, and a hot-melt resin such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene can be appropriately used.

[0064] The resin sheet 80 is provided as an insulation measure. The resin sheet 80 is provided to prevent short-circuiting of the outermost electrodes via the first and second metal layers 310, 320 ( Figure 2 , Figure 3 ). Specifically, the resin sheet 80 prevents short-circuiting and liquid bonding between the first and second metal layers 310, 320 ( Figure 2 , Figure 3 ) and the first conductive plate 18. The resin sheet 80 prevents short-circuiting and liquid bonding between the first metal layer 310 and the second metal layer 320 and the second conductive plate 19.

[0065] 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 laminated sheet portion 21 and the second laminated sheet portion 22. Specifically, the resin sheet 80 is welded to the resin layer 53 and the sealant resin layer 312 ( Figure 2 ) and the fourth resin layer 324 ( Figure 3 ) described later. The resin sheet 80 at least includes an acid-modified PP (PPa) layer. In this example, the resin sheet 80 has a layer structure similar to that of the resin sheet 50.

[0066] The central portions of the first conductive plate 18 and the second conductive plate 19 are exposed areas not covered by the resin sheet 50, the first laminated sheet portion 21, and the second laminated sheet portion 22. Current can be directly obtained from the internal storage battery module 1 to the outside via the exposed areas.

[0067] The first laminated sheet portion 21 includes a plurality of first sheets 31 and a plurality of second sheets 32 (see Figure 2 , Figure 3 , Figure 6A , Figure 6B , Figure 6C and Figure 6D ). The plurality of first sheets 31 and the plurality of second sheets 32 cooperate with each other to cover the peripheral edge of the first conductive plate 18. The second laminated 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 laminated sheet portion 22 cooperate with each other to cover the peripheral edge of the second conductive plate 19.

[0068] The first sheet 31 (see Figure 2 ) has a first metal layer 310 and sealant resin layers 311, 312. The first metal layer 310 has a sheet-like shape. In this example, as also shown in Figure 5E described later, 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 provides moisture permeation resistance, air permeability resistance, and chemical resistance to the first sheet 31.

[0069] The sealant resin layers 311, 312 are provided on both surfaces of the first metal layer 310. Specifically, the sealant resin layer 311 is provided on the inner front surface of the first metal layer 310. The sealant resin layer 312 is provided on the outer front surface of the first metal layer 310.

[0070] The sealant resin layers 311, 312 are compatible with the resin sheet 50. In this embodiment, polypropylene (PP) is used as the sealant resin layers 311, 312, but the present invention is not limited thereto, and thermoplastic resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene can be used as the sealant resin layers 311, 312.

[0071] The sealant resin layers 311, 312 serve as the sealing layer of the outer body 20. The sealant resin layers 311, 312 also have the function of an insulating layer, 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 to each other.

[0072] The second sheet 32 (see Figure 3)(2) 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 stacked in this order from the inside to the outside of the stacked battery 100. The fourth resin layer 324 is the outermost layer in the second sheet 32.

[0073] In this example, as also described later Figure 5F as 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 as 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.

[0074] The second metal layer 320 has a sheet-like shape. The second metal layer 320 has a first main surface 320a and a second main surface 320b. The first main surface 320a is the surface facing the inside (the side on which the stacked electrode body 10 is located), and the second main surface 320b is the surface facing the outside (the side opposite to the side on which the stacked electrode body 10 is located).

[0075] 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 can be thicker than the thickness of the first metal layer 310. The thickness of the second metal layer 320 can be the same as the thickness of the first metal layer 310.

[0076] The third resin layer 323 is compatible with the sealant resin layer 312. As the third resin layer 323, in addition to polypropylene (PP), hot-melt resins such as polyethylene, modified polyethylene, and modified polypropylene can also be used. Preferably, a resin material having immiscibility with the sealant resin layer 312 is used in the fourth resin layer 324.

[0077] In the second sheet 32, the nylon layer (second resin layer 322) and the polyethylene terephthalate layer (fourth resin layer 324) overlap on the outside of the second metal layer 320. Therefore, the combination of the layers on the outside of the second metal layer 320 has higher strength than the combination of the two layers (first resin layer 321 and third resin layer 323) on the inside of the second metal layer 320 in the second sheet 32. The expression "higher strength" means high rigidity or tensile strength. Therefore, damage to the second metal layer 320 can be appropriately prevented when the second sheet 32 receives a force such as piercing from the outside.

[0078] The sealant resin layer 312 of the first sheet 31 (see Figure 2 ) 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 on the outer side of 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 enhancing the strength of the second sheet 32, damage to the second sheet 32 during the deep drawing forming described later can be appropriately prevented.

[0079] The first laminated sheet portion 21 is deep drawn in a state of being joined to the first conductive plate 18. In other words, a stamping process is applied to the first laminated sheet portion 21. Therefore, the first laminated sheet portion 21 has a shape that is open upward and downward. A flange portion 21f that bends outward is provided at the open end on the lower side of the first laminated sheet portion 21.

[0080] The second laminated sheet portion 22 is deep drawn in a state of being joined to the second conductive plate 19. In other words, like the first laminated sheet portion 21, a stamping process is also applied to the second laminated sheet portion 22. Therefore, the second laminated sheet portion 22 has a shape that is open upward and downward. A flange portion 22f that bends outward is provided at the open end on the upper side of the second laminated sheet portion 22.

[0081] Accommodating recesses 21c and 22c for accommodating the inner power storage module 1 are provided on the first laminated sheet portion 21 and the second laminated sheet portion 22. A part of the first main surface 91, a part of the second main surface 92, and the peripheral surface 93 in the power storage module 1 are covered by the accommodating recesses 21c and 22c.

[0082] Specifically, the peripheral portions of the upper surface and the lower surface of the power storage module 1 and the peripheral surface of the power storage module 1 are covered by the accommodating recesses 21c and 22c. Specifically, the peripheral portions of the upper surface and the lower surface of the stacked electrode body 10 and the peripheral surface of the stacked electrode body 10 are covered by the accommodating recesses 21c and 22c. The central portion of the upper surface of the stacked electrode body 10 is covered by the first conductive plate 18. The central portion of the lower surface of the stacked electrode body 10 is covered by the second conductive plate 19.

[0083] For example, the accommodation recesses 21c and 22c are formed by sections obtained by applying the above stamping process to the first laminated sheet portion 21 and the second laminated sheet portion 22. The accommodation recesses 21c and 22c are not limited to these sections and only need to be provided so as to be able to accommodate the stacked electrode bodies 10. In the above description, 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 illustrated, but the accommodation recesses may be provided only in one of the first laminated sheet portion 21 and the second laminated sheet portion 22.

[0084] The first sheet 31 has an inner end portion 31i on the central side of the stacked electrode bodies 10. The second sheet 32 has an inner end portion 32i on the central side of the stacked electrode bodies 10. The resin sheet 50 has an inner edge portion 50i and an outer edge portion 50c on the central side of the stacked electrode bodies 10.

[0085] The inner edge portion 50i is positioned closer to the central side of the stacked electrode bodies 10 than the inner end portions 31i and 32i, so as to ensure an insulation distance between the first metal layer 310 included in the first sheet 31 and the second metal layer 320 included in the second sheet 32 and the first conductive plate 18 and the second conductive plate 19.

[0086] The first conductive plate 18 has an outer edge portion 18c. The second conductive plate 19 has an outer edge portion 19c. The inner end portions 31i and 32i are positioned closer to the central side of the stacked electrode bodies 10 than the outer edge portions 18c and 19c.

[0087] The portions of the first conductive plate 18 and the second conductive plate 19 that overlap with the resin sheet 50 are welded. The joint interface of the overlapping portions is sealed.

[0088] The outer edge portion 50c of the resin sheet 50 is located outside the outer edge portions 18c and 19c, but is not limited thereto, and the outer edge portion 50c and the outer edge portions 18c and 19c may be flush with each other.

[0089] 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 cases where the first conductive plate 18 and the second conductive plate 19 are short-circuited via the first sheet 31 having the first metal layer 310 or the second sheet 32 having the second metal layer 320 are reduced.

[0090] 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 provided in a state facing the peripheral surface 93 (specifically, the end surfaces 93a and 93c) of the power storage module 1.

[0091] Figure 4 is a perspective view of the structure 60. As Figure 4As shown, in this example, the structure 60 has a box-like shape. The structure 60 is generally 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 Figure 3 ).

[0092] The structure 60 further includes two wall portions 62 and 64 which extend from the base portion 61 parallel to the first main surface 91 of the power storage module 1 and extend in the DR2 direction toward the peripheral surface 93. The structure 60 further includes two wall portions 63 and 65 which extend from the base portion 61 perpendicular to the first main surface 91 and extend in the DR2 direction toward the peripheral surface 93.

[0093] The wall portions 62, 63, 64, and 65 standing up from the base portion 61 are continuous with each other in the above 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. A rectangular parallelepiped space 690 having an opening is formed by the base portion 61 and each of the wall portions 62, 63, 64, and 65.

[0094] The structure 60 has an outer front surface 60s and an inner front surface 60t on the peripheral surface 93 side of the outer front surface 60s. In the structure 60, a through hole 60h is formed which passes through the structure 60 from the inner front surface 60t to the outer front surface 60s. 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.

[0095] The first laminate sheet portion 21 and the second laminate sheet portion 22 (see Figure 1 ), which construct the outer body 20, are provided to cover the outer front surface 60s of the structure 60. Specifically, each of the first laminate sheet portion 21 and the second sheet 32 of the second laminate sheet portion 22 (see Figure 3 ) is provided to cover the outer front surface 60s of the structure 60.

[0096] As described above, the sealed internal space 800 ( Figure 3 ) is formed between the inner front surface 60t of a part of the base portion 61 in the structure 60 and the end surface 93a of the power storage module 1 by each of the second sheets 32 of the first laminate sheet portion 21 and the second laminate sheet portion 22. The internal space 800 is decompressed so as to have a negative pressure with respect to the air pressure (atmospheric pressure in this example) of the external space of the stacked battery 100. In this example, the internal space 800 is decompressed to about 1 kilopascal (kPa) in the initial state. The internal space 800 is placed in a low vacuum state by evacuation. A binding force is applied to the stacked electrode bodies 10 by the pressure (air pressure) difference between the internal space 800 and the external space of the stacked battery 100 generated by this decompression.

[0097] As Figure 3 shown, the pipe 90 is passed through the through-hole 60h. In this example, the distal end of the pipe 90 reaches the internal space 800. The outer peripheral surface of the pipe 90 contacts the wall surface of the through-hole 60h. A part of the pipe 90 is sandwiched between the second sheet 32 of the first laminated sheet portion 21 and the second sheet 32 of the second laminated sheet portion 22. The third resin layer 323, which is the innermost layer of each second sheet 32, is welded to the outer peripheral surface of the pipe 90.

[0098] The suction machine 910 sucks the air in the internal space 800 of the stacked battery 100 via the pipe 90. The pressure gauge 920 measures the air pressure in the internal space 800 of the stacked battery 100 by measuring the air pressure inside the pipe 90. The pressure gauge 920 notifies the measured air pressure to the suction machine 910 via a signal line (not shown).

[0099] 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.

[0100] 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 less than the threshold Th2, which is lower than the threshold Th1, the control device 912 stops the suction pump 911. As described above, the control device 912 controls the operation of the suction pump 911 such that the value indicated by the pressure gauge 920 (hereinafter referred to as P) falls within a predetermined range (threshold Th1 ≥ P ≥ threshold Th2). The threshold Th1 is a value (e.g., 5 kPa) that is sufficiently lower than the atmospheric pressure (about 101.325 kPa). The threshold Th2 is, for example, 1 kPa.

[0101] As described above, the stacked battery 100 includes: a power storage module 1 having a stacked electrode body 10; an outer body 20 that houses the power storage module 1 and forms a sealed internal space 800 between the outer 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 stacked battery 100. In the stacked battery 100, the air pressure in the internal space 800 is maintained at a negative pressure with respect to the air pressure in the external space of the stacked battery 100 by a suction device 900 that sucks the gas via the pipe 90.

[0102] There is a risk that air (nitrogen, oxygen, etc.) enters the internal space 800 of the stacked battery 100 from the outside of the stacked battery 100. For example, when there is a problem in the welding between the first laminated sheet portion 21 and the second laminated sheet portion 22, air can enter through the gap between the flange portion 21f and the flange portion 22f.

[0103] However, in the stacked battery 100, even when air enters the internal space 800, the air in the internal space 800 is sucked through the pipe 90 and the suction device 900. Therefore, the air pressure in the internal space 800 does not become negative relative to the air pressure in the external space. Accordingly, even when air enters the internal space 800 of the stacked battery 100 from the external space, an appropriate binding force can continue to be applied to the stacked electrode bodies 10.

[0104] Specifically, when focusing on the first main surface 91 among the first main surface 91 and the second main surface 92, the stacked battery 100 has the following configuration. The power storage module 1 has a first main surface 91 and a peripheral surface 93 perpendicular to the first main surface 91. As Figure 3 shown, the stacked battery 100 further includes a structure body 60 accommodated in the outer body 20. As Figure 4 shown, the structure body 60 has an outer front surface 60s and an inner front surface 60t on the peripheral surface 93 side of the outer front surface 60s, and is disposed in a state facing the peripheral surface 93. The outer body 20 further includes a second sheet 32 provided to cover the outer front surface 60s. The internal space 800 is formed between the inner front surface 60t and the peripheral surface 93 by being sealed by the second sheet 32. In the structure body 60, a through hole 60h is formed, which passes through the structure body 60 from the outer front surface 60s to the inner front surface 60t. The pipe 90 reaches the internal space 800 via the through hole 60h.

[0105] According to this configuration, the air in the internal space 800 can be sucked through the pipe 90. The case where the pipe 90 is closed in the outer body 20 can be reduced by the structure body 60.

[0106] More specifically, the stacked 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 via 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 such that the air pressure measured by the pressure gauge 920 becomes at least equal to or less than a threshold Th1 lower than the air pressure in the external space. According to this configuration, the air pressure in the internal space 800 can be maintained equal to or less than the threshold Th1 lower than the air pressure in the external space.

[0107] Figure 5A 、 Figure 5B 、 Figure 5C 、 Figure 5D 、 Figure 5E 、 Figure 5F and Figure 5G are diagrams for describing the manufacturing method of the first laminated sheet portion 21. AsFigure 5A As shown, an aluminum plate is prepared to be used as the first conductive plate 18. As Figure 5B shown, two resin sheets 50 are welded along two long edges of the aluminum plate. Next, as Figure 5C shown, two resin sheets 50 are welded along two short sides of the aluminum plate. The resin sheets 50 on the long edge side and the resin sheets 50 on the short edge side overlap at the four corner portions as Figure 5C shown.

[0108] As Figure 5D shown, two resin sheets 70 are welded to each of the two resin sheets 50 on the long edge side. Each resin sheet 70 has the same layer structure as the resin sheet 50 in this example. The two resin sheets 70 on the right side 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 edge side in a state of protruding from the resin sheets 50 in a plurality of directions on the side opposite to the aluminum plate.

[0109] As Figure 5E shown, a first sheet 31 is welded to the resin sheet 50 and the two resin sheets 70 on the right side of the drawing. Similarly, a first sheet 31 is also welded to the resin sheet 50 and the two resin sheets 70 on the left side of the drawing. Each first sheet extends in the DR2 direction. Each first sheet is longer than the spacing distance between the resin sheets 70 in the DR2 direction.

[0110] As Figure 5F shown, a second sheet 32 is welded to the resin sheet 50 on the upper side of the drawing, the two resin sheets 70 on the upper side of the drawing, and the ends of the two first sheets 31 (the upper ends in the drawing). The second sheet 32 has a U shape. Similarly, a second sheet 32 is also welded to the resin sheet 50 on the lower side of the drawing, the two resin sheets 70 on the lower side of the drawing, and the ends of the two first sheets 31 (the lower ends in the drawing). The second sheets 32 are in a state of facing the DR2 direction by being spaced apart from each other. As Figure 5F shown, the intermediate body of the first laminated sheet portion 21 is line-symmetric in each of the DR1 direction and the DR2 direction.

[0111] By applying a stamping process to the intermediate body along the dotted line L, as Figure 5G shown, the first laminated sheet portion 21 is generated. By the stamping process, the flange portion 21f of the first laminated sheet portion 21 is formed.

[0112] The first laminated sheet portion 21 and the second laminated sheet portion 22 have the same shape. The second laminated sheet portion 22 is also manufactured by a method similar to the method of the first laminated sheet portion 21. Therefore, the description of the manufacturing method of the second laminated sheet portion 22 will not be repeated here.

[0113] Figure 6A , Figure 6B , Figure 6C and Figure 6D are diagrams for describing the method of manufacturing the stacked battery 100 from the power storage module 1 and the outer body 20. As Figure 6A and Figure 6B shown, the structure 60 is mounted on one of the two short-edge sides of the power storage module 1. The structure 60 is mounted at a position facing the end surface 93a of the peripheral surface 93 of the power storage module 1.

[0114] In this example, the stacked battery 100 further includes structures 60A, 60B. The structures 60A, 60B have a structure and function similar to that of the structure 60. However, the through holes 60h are not formed in the structures 60A, 60B. The length of the structure 60A in the DR1 direction is shorter than the length of the structure 60 in the DR1 direction. The length of the structure 60B in the DR1 direction is longer than the length of the structure 60 in the DR1 direction. Like the structure 60, the structures 60A, 60B are accommodated in the outer body 20.

[0115] The structure 60A is mounted on the same side as the structure 60. Like the structure 60, the structure 60A is mounted such that the opening side faces the end surface 93a. The structure 60B is mounted on the short side on the opposite side of the structure 60. The structure 60B is mounted at a position facing the end surface 93c of the power storage module 1. Specifically, the structure 60B is mounted such that the opening side faces the end surface 93c.

[0116] As Figure 6C shown, the pipe 90 is passed through the through hole 60h in the structure 60. The power storage module 1 and the three structures 60, 60A, 60 are sandwiched between the first laminated sheet portion 21 and the second laminated sheet portion 22. The second laminated sheet portion 22 is in a face-down state. Then, the first laminated sheet portion 21 and the second laminated sheet portion 22 are welded to each other. As a result, the stacked battery 100 is completed, as Figure 6D shown.

[0117] Improved example

[0118] In the above description, the configuration in which the stacked battery 100 includes the pipe 90 and the suction device 900 has been described. The configuration in which a plurality of stacked batteries 100 share one suction device will be described below.

[0119] Figure 7 This is a diagram for describing the energy storage system SYS. As Figure 7 shown, the energy storage system SYS includes a plurality of stacked batteries 100 and a suction device 900A.

[0120] The suction device 900A has a suction machine 910, a pressure gauge 920A, a pipe 950, and a plurality of valves 960.

[0121] The pipe 950 connects the pipe 90 of the stacked battery 100 and the suction pump 911 of the suction device 900 to each other. The pipe 950 has a main pipe 951 and a plurality of branch pipes 952. Each branch pipe 952 is joined to the main pipe 951. The suction pump 911 is connected to the main pipe 951. Each branch pipe 952 is connected to each valve 960 that is different from each other. Each valve 960 is connected to each pipe 90 that is different from each other. A pipe 90 and a branch pipe 952 are connected to each other through a valve 960.

[0122] 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 an open state, the pressure gauge 920A measures the average value of the air pressure in the internal space 800 of the plurality of stacked batteries 100.

[0123] The suction pump 911 can suck the gas contained in the internal space 800 of each stacked battery 100 via each pipe 90 and the pipe 950. Specifically, when each valve 960 is in an open state, the suction pump 911 can suck the gas contained in each internal space 800.

[0124] In this example, the control device 912 controls the operation of the suction pump 911 such that the air pressure measured by the pressure gauge 920A becomes at least equal to or less than a threshold Th1 that is lower than 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 causes the suction pump 911 to operate. When the value of the air pressure becomes equal to or less than a threshold Th2 that is lower than the threshold Th1, the control device 912 stops the suction pump 911. As described above, the control device 912 controls the operation of the suction pump 911 such that the value P indicated by the pressure gauge 920A falls within a predetermined range (threshold Th1 ≥ P ≥ threshold Th2).

[0125] According to this configuration, the internal space 800 of each stacked battery 100 can be simultaneously depressurized by one suction pump 911. Therefore, the air pressure in the internal space 800 of each stacked battery 100 can be maintained equal to or less than the threshold Th1 that is lower than the air pressure in the external space.

[0126] Each valve 960 may have a configuration that automatically opens and closes based on instructions from the control device 912. In the case of this configuration, the control device 912 controls the opening and closing of each valve such that only one of the plurality of valves 960 is continuously placed in the open state. The control device 912 controls the operation of the suction pump 911 such that the air pressure in the internal space 800 measured by the pressure gauge 920A becomes equal to or less than the threshold Th1. According to this configuration, the air pressure in each internal space 800 can be measured individually by the pressure gauge 920A, and the air pressure in each internal space 800 can be individually set to be equal to or less than the threshold Th1.

[0127] The embodiments disclosed above are merely examples in all respects and are in no way intended to limit the present invention. The scope of the present disclosure is defined by the scope of the claims. All variations made within the scope and spirit equivalent to the claims are included in the present disclosure.

Claims

1. An electric storage device, comprising: A power storage module having stacked electrode bodies; an outer body, the outer body accommodating the power storage module and forming a sealed internal space between the outer body and the power storage module; as well as A first piping that discharges the gas contained in the internal space to the outside of the power storage device, wherein the air pressure of the internal space of the power storage device is maintained at a negative pressure relative to the air pressure of the external space of the power storage device by a suction device that sucks the gas through the first piping.

2. The power storage device according to claim 1, further comprising a structure housed in the outer body, wherein: The power storage module has a main surface and a peripheral surface perpendicular to the main surface; The structure has an outer front surface and an inner front surface on the peripheral surface side of the outer front surface, and is disposed in a state facing the peripheral surface; The outer body comprises a laminated sheet body, the laminated sheet body being arranged to cover the outer front surface; The internal space is formed between the inner front surface and the peripheral surface by sealing with the laminate sheet body; a through hole is formed in the structure body, the through hole passing through the structure body from the outer front surface to the inner front surface; and The first pipe reaches the internal space through the through hole.

3. The power storage device according to claim 1 or 2, further comprising the suction device, wherein: The suction device comprises: 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 for measuring the air pressure in the first pipe, and The control device controls the operation of the pump so that the air pressure measured by the pressure gauge becomes equal to or less than a threshold value, which is lower than the air pressure of the external space.

4. A power storage system comprising a plurality of power storage devices according to claim 1 or 2, the power storage system further comprising the pumping device, wherein: The suction device comprises: Pumps; a second pipe connecting the first pipe of each of the power storage devices and the pump to each other; a control device that controls the operation of the pump; and a pressure gauge for measuring the air pressure in the second pipe, The pump is capable of sucking gas contained in an internal space of each of the power storage devices through the first pipe and the second pipe, and The control device controls the operation of the pump so that the air pressure measured by the pressure gauge becomes equal to or less than a threshold value, which is lower than the air pressure of the external space.

Images