Power storage module and method for manufacturing same

Abstract

The invention provides a power storage module and a method of manufacturing the same. In a power storage module, a sealing sheet covers an end portion of a current collector foil of a plurality of electrode plates in a first direction. The sealing sheet comprises a plurality of side wall parts, a plurality of fold-in parts and a fold-back part. The plurality of side wall portions are respectively disposed on the outer side of the collector foil of the plurality of electrode plates in the first direction. The plurality of folded portions are folded from each of the plurality of side wall portions toward between the plurality of electrode plates. The folded-back portion connects the plurality of folded-in portions adjacent to each other between the plurality of electrode plates. At least a portion of each of the plurality of fold-in portions is welded to the collector foil of the corresponding plurality of electrode plates.

Description

Technical Field

[0001] The present disclosure relates to a power storage module and a method for manufacturing the same. Background Art

[0002] A power storage device including a plurality of bipolar batteries is disclosed in Japanese Unexamined Patent Application Publication No. 2019-91606. The bipolar battery includes an electrode laminate portion and a sealing frame. The electrode laminate portion is formed by laminating a plurality of bipolar electrodes with a spacer interposed therebetween. The bipolar electrode has a nickel foil, a positive electrode, and a negative electrode. The sealing frame is disposed so as to surround the electrode laminate portion. The sealing frame has a plurality of primary sealing portions and secondary sealing portions. The plurality of primary sealing portions respectively hold the edges of the nickel foils. An internal space partitioned by the nickel foil, the positive electrode, the negative electrode, and the primary sealing portion is provided between the nickel foils adjacent in the stacking direction. The primary sealing portion seals the internal space. The secondary sealing portion surrounds each primary sealing portion and further seals the internal space. Summary of the Invention

[0003] In a power storage device including a conventional power storage module, a plurality of sealing members are used to seal between electrode plates. Therefore, in the power storage module, the number of parts increases due to these sealing members, and the structure of the power storage module is complicated. In addition, there is a limit to reducing each sealing member, so there is a possibility that the space efficiency deteriorates, and it is difficult to increase the energy density of the power storage module.

[0004] The present disclosure has been made in view of the above problems, and an object thereof is to provide a power storage module that can reduce the number of parts in the power storage module, simplify the structure of the power storage module, and increase the possibility of providing a power storage module with a high energy density.

[0005] The power storage module according to the first aspect of the present disclosure includes a plurality of electrode plates, a plurality of spacers, and a sealing sheet. Each of the plurality of electrode plates includes a current collector foil and at least one active material layer applied to the current collector foil. The surface direction of each of the plurality of electrode plates extends along a first direction. The plurality of electrode plates are arranged adjacent to each other in a second direction orthogonal to the first direction. The plurality of spacers are respectively disposed between the active material layers of the plurality of adjacent electrode plates. The sealing sheet covers the end portions of the current collector foils of the plurality of electrode plates in the first direction. The sealing sheet includes a plurality of side wall portions, a plurality of folded portions, and a folded-back portion. The plurality of side wall portions are respectively disposed outside the current collector foils of the plurality of electrode plates in the first direction. The plurality of folded portions are folded from each of the plurality of side wall portions toward between the plurality of electrode plates. The folded-back portion connects the plurality of adjacent folded portions to each other between the plurality of electrode plates. At least a part of the plurality of folded portions is fused to the current collector foils of the corresponding plurality of electrode plates.

[0006] Thus, the sealing sheet can seal between multiple electrode plates and can function as an exterior member for the multiple electrode plates. Therefore, the number of components of the power storage module can be reduced. Moreover, the structure of the power storage module can be simplified. Further, according to the above structure, the current collector foils can be sealed by a relatively thin sealing sheet, so that the volume ratio of the multiple electrode plates in the power storage module can be increased, and the energy density of the power storage module can be improved.

[0007] In the above power storage module, the sealing sheet may also include a resin layer and a metal layer. The metal layer may be provided on the surface of the resin layer opposite to the surface facing the multiple electrode plates. Thus, it is possible to suppress moisture permeation in the power storage module without providing other components different from the sealing sheet.

[0008] In the above power storage module, the resin layer may also contain a polypropylene-based resin or a polyethylene-based resin. Thus, the water absorption rate of the resin layer can be reduced.

[0009] In the above power storage module, a groove portion may be formed in the resin layer at the folded-back portion. Thus, the stress at the folded-back portion of the sealing sheet can be alleviated.

[0010] In the above power storage module, the sealing sheet may also further include an outer resin layer. The outer resin layer may be provided on the surface of the metal layer opposite to the surface in contact with the resin layer. Thus, it is possible to easily insulate the outside of the metal layer.

[0011] In the above power storage module, at least a part of the outer resin layers of the multiple folded-in portions may be fused to each other between the multiple electrode plates. Thus, the shape of the sealing sheet can be maintained more firmly.

[0012] In the above power storage module, each of the multiple electrode plates may include a first active material layer coated on the current collector foil and a second active material layer coated on the current collector foil. The first active material layer may be located on one side in the second direction of the current collector foil. The second active material layer may be located on the other side in the second direction of the current collector foil. One of the first active material layer and the second active material layer may be a negative electrode active material layer, and the other may be a positive electrode active material layer. Multiple spacers may be respectively disposed between the adjacent first active material layer and second active material layer.

[0013] Thus, each of the plurality of electrode plates becomes a bipolar electrode, and the power storage module becomes a bipolar battery. In the power storage module as a bipolar battery, the potentials of the plurality of current collector foils are different from each other. In order to suppress short circuit occurrence, it is important to suppress the plurality of current collector foils from contacting each other. Here, according to the above-described power storage module, by forming a plurality of folded portions and folded-back portions with one sealing sheet material, contact between the current collector foils can be suppressed. Furthermore, as described above, the sealing sheet material can also function as an exterior member. Therefore, when the power storage module is a bipolar battery, the number of component parts can be made extremely small compared to conventional bipolar batteries.

[0014] The above-described power storage module may also be a power storage module including a bipolar battery.

[0015] In a power storage module including a bipolar battery, the potentials of the plurality of current collector foils are different from each other. In order to suppress short circuit occurrence, it is important to suppress the plurality of current collector foils from contacting each other. Here, according to the above-described power storage module, by forming a plurality of folded portions and folded-back portions with one sealing sheet material, contact between the current collector foils can be suppressed. Furthermore, as described above, the sealing sheet material can also function as an exterior member. Therefore, the number of component parts can be made extremely small compared to conventional bipolar batteries.

[0016] The method for manufacturing a power storage module according to the second aspect of the present disclosure includes: disposing a spacer on an active material layer on one surface side of a first electrode plate, the first electrode plate including a current collector foil and at least one active material layer coated on the current collector foil; folding a sealing sheet material from the other surface side of the current collector foil of the first electrode plate so as to cover an end portion of the current collector foil of the first electrode plate and a part of one surface of the current collector foil of the first electrode plate; fusing the sealing sheet material to a part of one surface of the current collector foil of the first electrode plate; folding back the sealing sheet material on the one surface side of the current collector foil of the first electrode plate; fusing the folded-back sealing sheet material to a part of the other surface, opposite to the one surface, of the current collector foil in a second electrode plate, the second electrode plate including a current collector foil and at least one active material layer coated on the current collector foil; folding the folded-back sealing sheet material from the other surface side of the current collector foil of the second electrode plate so as to cover an end portion of the current collector foil of the second electrode plate and a part of one surface of the current collector foil of the second electrode plate; and disposing the active material layer of the second electrode plate on the spacer.

[0017] Thus, the sealing sheet can seal between the current collector foil of the first electrode plate and the current collector foil of the second electrode plate, and can function as an exterior member of the first electrode plate and the second electrode plate. Therefore, the number of components of the power storage module can be reduced. Moreover, the structure of the power storage module can be simplified. Further, according to the above structure, since the sealing sheet with a relatively thin thickness can seal between the current collector foil of the first electrode plate and the current collector foil of the second electrode plate, the volume ratio of the first electrode plate and the second electrode plate in the power storage module can be increased, and the energy density of the power storage module can be improved.

[0018] In the method for manufacturing the power storage module described above, the step of disposing the active material layer of the second electrode plate on the spacer may also be performed after a part of one side of the sealing sheet is melted and adhered to the current collector foil of the first electrode plate and after a part of the other side of the folded-back sealing sheet is melted and adhered to the current collector foil of the second electrode plate.

[0019] Thus, the sealing sheet can be melted and adhered in the process of laminating the first electrode plate, the spacer, and the second electrode plate to each other. Moreover, the number of manufacturing processes of the power storage module can be reduced.

[0020] The above and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the present invention understood in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a perspective view schematically showing a power storage module according to Embodiment 1 of the present disclosure.

[0022] Figure 2 is a cross-sectional view of a part of the power storage module viewed in the direction of the arrow along line II-II Figure 1 of the power storage module.

[0023] Figure 3 is a cross-sectional view of a part of the power storage module according to the comparative example.

[0024] Figure 4 FIG. is a flowchart showing a method for manufacturing the power storage module according to Embodiment 1 of the present disclosure.

[0025] Figure 5 is a flowchart showing Step S1 of the method for manufacturing the power storage module.

[0026] Figures 6A - 6E is a schematic cross-sectional view schematically showing the process of Step S1.

[0027] Figure 7 is a flowchart showing a part of Step S2 of the method for manufacturing the power storage module.

[0028] Figures 8A - 8FIt is a schematic cross-sectional view showing a part of the process of step S2.

[0029] Figures 9A - 9F is schematically shown Figures 8A - 8F A continued schematic cross-sectional view showing a part of the process of step S2 shown above.

[0030] Figure 10 It is a flowchart showing step S3 of the manufacturing method of the power storage module.

[0031] Figures 11A - 11E It is a schematic cross-sectional view showing the process of step S3.

[0032] Figure 12 It is a cross-sectional view showing a part of the power storage module according to Embodiment 2 of the present disclosure.

[0033] Figure 13 It is a cross-sectional view showing a part of the power storage module according to Embodiment 3 of the present disclosure. Detailed Embodiments

[0034] Hereinafter, with reference to the drawings, the power storage module according to each embodiment of the present disclosure will be described. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

[0035] (Embodiment 1)

[0036] Figure 1 It is a perspective view schematically showing the power storage module according to Embodiment 1 of the present disclosure. Figure 2 It is viewed from the direction of the arrow along line II-II Figure 1 A cross-sectional view of a part of the power storage module.

[0037] As Figure 1 and Figure 2 shown, the power storage module 1 according to Embodiment 1 of the present disclosure includes a plurality of electrode plates 10, a first terminal electrode 20, a second terminal electrode 30, a plurality of spacers 40, and a sealing sheet 50.

[0038] The power storage module 1 can be a secondary battery such as a lithium-ion battery. The first terminal electrode 20, the second terminal electrode 30, and the sealing sheet 50 can also be the outer package of the secondary battery. Either one of the first terminal electrode 20 and the second terminal electrode 30 can be the positive external terminal of the secondary battery, and the other can be the negative external terminal. The power storage module 1 is arranged so that current can be taken out to the outside from the first terminal electrode 20 and the second terminal electrode 30.

[0039] The surface directions of the respective electrode plates 10 of the plurality of electrode plates are along the first direction D1. The plurality of electrode plates 10 are arranged side by side in the second direction D2 orthogonal to the first direction D1. The electrode plate 10 has an outer shape, for example, a rectangular shape when viewed from the second direction D2.

[0040] The electrode plate 10 has an end portion 11. The end portion 11 is located at one end of the electrode plate 10 in the first direction D1. The electrode plate 10 has a first surface 12 and a second surface 13. The first surface 12 is located on one side of the second direction D2. The second surface 13 is located on the other side of the second direction D2.

[0041] The electrode plate 10 is, for example, a bipolar electrode. Therefore, in the present embodiment, the power storage module 1 is exemplified as a bipolar battery (a bipolar-type battery). The electrode plate 10 includes a current collector foil 110, a first active material layer 120, and a second active material layer 130.

[0042] The current collector foil 110 extends along the first direction D1. The current collector foil 110 forms the end portion 11 of the electrode plate 10. The current collector foil 110 forms a part of the first surface 12 and a part of the second surface 13 of the electrode plate 10.

[0043] The current collector foil 110 includes a first current collector 112 and a second current collector 113. The first current collector 112 and the second current collector 113 are laminated on each other in the second direction D2. The first current collector 112 forms a part of the first surface 12 of the electrode plate 10. The second current collector 113 forms a part of the second surface 13 of the electrode plate 10. The first current collector 112 and the second current collector 113 may contain different metals from each other. In addition, the current collector foil 110 may be composed of one component.

[0044] The current collector foil 110 (each current collector of the first current collector 112 and the second current collector 113) may also 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), copper (Cu), and zinc (Zn). The current collector foil 110 may also be a current collector foil obtained by performing plating processing on the surface of a metal foil.

[0045] Regarding the first current collector 112 and the second current collector 113, one of them may be a negative electrode current collector and the other may be a positive electrode current collector. In the present embodiment, the first current collector 112 is a negative electrode current collector and the second current collector 113 is a positive electrode current collector. The negative electrode current collector preferably contains copper (Cu). The positive electrode current collector preferably contains aluminum (Al).

[0046] The first active material layer 120 is located on one side of the current collector foil 110 in the second direction D2. The first active material layer 120 is disposed on the first current collector 112. The first active material layer 120 forms another part of the first surface 12 of the electrode plate 10. The first active material layer 120 is formed by coating the first active material on one side in the second direction D2. More specifically, it is formed by coating the first active material on the first current collector 112.

[0047] The second active material layer 130 is located on the other side of the current collector foil 110 in the second direction D2. The second active material layer 130 is disposed on the second current collector 113. The second active material layer 130 forms another part of the second surface 13 of the electrode plate 10. The second active material layer 130 is formed by coating the second active material on the other side in the second direction D2. More specifically, it is formed by coating the second active material on the second current collector 113.

[0048] Regarding the first active material layer 120 and the second active material layer 130, one of them can be a negative electrode active material layer and the other can be a positive electrode active material layer. Regarding the first active material and the second active material, one of them can be a negative electrode active material and the other can be a negative electrode active material. In the present embodiment, the first active material layer 120 is a negative electrode active material layer, the first active material is a negative electrode active material, the second active material layer 130 is a positive electrode active material layer, and the second active material is a positive electrode active material.

[0049] As the negative electrode active material, for example, lithium, carbon, metal compounds, and elements or their compounds that can be alloyed with lithium can be used.

[0050] As the positive electrode active material, for example, a material that can occlude and release 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-based compound, and the like, which can be used as the positive electrode active material of a lithium ion secondary battery, can be used. In addition, two or more positive electrode active materials can be used in combination. For example, the positive electrode active material can also contain olivine-type lithium iron phosphate (LiFePO4).

[0051] The first terminal electrode 20 has an end portion 21. The end portion 21 is located at one end of the first terminal electrode 20 in the first direction D1. The first terminal electrode 20 has a first surface 22 and a second surface 23. The first surface 22 is located on one side of the second direction D2. The second surface 23 is located on the other side of the second direction D2.

[0052] The first terminal electrode 20 includes a current collector foil 110 and a first active material layer 120. Except for the second surface 23 side, the current collector foil 110 and the first active material layer 120 of the first terminal electrode 20 may also have the same structures as those that the current collector foil 110 and the first active material layer 120 of the electrode plate 10 may respectively have. In the present embodiment, except for the second surface 23 side, the current collector foil 110 and the first active material layer 120 of the first terminal electrode 20 have the same structures as those of the current collector foil 110 and the first active material layer 120 of the electrode plate 10 respectively.

[0053] In the first terminal electrode 20, the current collector foil 110 (the second current collector 113) forms the entirety of the second surface 23 of the first terminal electrode 20. The first terminal electrode 20 is located more outward in the second direction D2 than the plurality of electrode plates 10. The plurality of electrode plates 10 are located on the first surface 22 side of the first terminal electrode 20.

[0054] The second terminal electrode 30 has an end portion 31. The end portion 31 is located at one end of the second terminal electrode 30 in the first direction D1. The second terminal electrode 30 has a first surface 32 and a second surface 33. The first surface 32 is located on one side of the second direction D2. The second surface 33 is located on the other side of the second direction D2.

[0055] The second terminal electrode 30 includes a current collector foil 110 and a second active material layer 130. Except for the first surface 32 side, the current collector foil 110 and the second active material layer 130 of the second terminal electrode 30 may also have the same structures as those that the current collector foil 110 and the second active material layer 130 of the electrode plate 10 may respectively have. In the present embodiment, except for the first surface 22 side, the current collector foil 110 and the second active material layer 130 of the second terminal electrode 30 have the same structures as those of the current collector foil 110 and the second active material layer 130 of the electrode plate 10 respectively.

[0056] In the second terminal electrode 30, the current collector foil 110 (the first current collector 112) forms the entirety of the first surface 32 of the second terminal electrode 30. The second terminal electrode 30 is located more outward in the second direction D2 than the plurality of electrode plates 10. The plurality of electrode plates 10 are located on the second surface 33 side of the second terminal electrode 30.

[0057] Regarding the first terminal electrode 20 and the second terminal electrode 30, one of them may be a negative terminal electrode and the other may be a positive terminal electrode. In the present embodiment, the first terminal electrode 20 is a negative terminal electrode and the second terminal electrode 30 is a positive terminal electrode.

[0058] A plurality of spacers 40 are respectively disposed between the mutually adjacent first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30. The first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30 are laminated in the second direction D2 with the spacers 40 therebetween.

[0059] The spacers 40 are disposed between the active material layers adjacent to each other in the second direction D2. More specifically, the spacers 40 are in contact with both the first active material layer 120 and the second active material layer 130 adjacent in the second direction D2. The spacer 40 may also be fused to any one of the two current collector foils 110 adjacent in the second direction D2. When viewed from the electrode plate 10 or the first terminal electrode 20, the spacer 40 located on the side of the first surfaces 12 and 22 is fused to the current collector foil 110 of the electrode plate 10 or the first terminal electrode 20. That is, the spacer 40 is fused to the adjacent first current collector 112.

[0060] The spacer 40 is formed in a sheet shape. Examples of the spacer 40 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, etc. The spacer 40 may also be a material reinforced with a vinylidene fluoride resin compound.

[0061] The sealing sheet 50 covers the respective ends 21, 11, and 31 of the first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30 in the first direction D1. The sealing sheet 50 includes a plurality of side wall portions 51, a plurality of folded-in portions 52, a plurality of folded-back portions 53, a first edge portion 54, and a second edge portion 55.

[0062] The plurality of side wall portions 51 are respectively disposed outside the first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30 in the first direction D1. The side wall portion 51 faces the ends 21, 11, and 31 of the first terminal electrode 20, the plurality of electrode plates 10, or the second terminal electrode 30 adjacent in the first direction D1. Specifically, the side wall portion 51 is in contact with the ends 21, 11, and 31. The side wall portion 51 may not be in contact with the ends 21, 11, and 31.

[0063] The plurality of folded-in portions 52 are folded in from each of the plurality of side wall portions 51 toward between the first terminal electrode 20 and the electrode plate 10, between the plurality of mutually adjacent electrode plates 10, and between the electrode plate 10 and the second terminal electrode 30. Each of the plurality of folded-in portions 52 extends parallel to the first direction D1.

[0064] A pair of folded-in portions 52 are respectively located between the first terminal electrode 20 and the electrode plate 10, between a plurality of mutually adjacent electrode plates 10, and between the electrode plate 10 and the second terminal electrode 30. The pair of folded-in portions 52 are arranged in the second direction D2. The pair of folded-in portions 52 may be in contact with each other or isolated. In the present embodiment, the pair of folded-in portions 52 are in contact with each other.

[0065] A plurality of folded-in portions 52 are respectively fused to the corresponding plurality of electrode plates 10. Specifically, the folded-in portion 52 facing the first surface 12, 22 of the electrode plate 10 or the first terminal electrode 20 is fused to the first surface 12, 22 of the collector foil 110 (the first collector 112) in the first surface 12, 22 of the electrode plate 10 or the first terminal electrode 20. The folded-in portion 52 facing the second surface 13, 23 of the electrode plate 10 or the second terminal electrode 30 is fused to the second surface 13, 23 of the collector foil 110 (the second collector 113) in the second surface 13, 23 of the electrode plate 10 or the second terminal electrode 30.

[0066] A plurality of folded-back portions 53 connect the mutually adjacent folded-in portions 52 to each other between the first terminal electrode 20 and the electrode plate 10, between a plurality of mutually adjacent electrode plates 10, and between the electrode plate 10 and the second terminal electrode 30. That is, the folded-back portion 53 connects the pair of folded-in portions 52 to each other.

[0067] The first edge portion 54 is located at one edge of the sealing sheet 50. The first edge portion 54 extends from the side wall portion 51 outside in the first direction D1 of the first terminal electrode 20. The first edge portion 54 extends parallel to the first direction D1. The first edge portion 54 faces the second surface 23 of the first terminal electrode 20 in the second direction D2. The first edge portion 54 is in contact with the second surface 23 of the first terminal electrode 20. The first edge portion 54 is fused to the second surface 23 of the first terminal electrode 20. The first edge portion 54 is in contact with the second collector 113 of the first terminal electrode 20. The first edge portion 54 is fused to the second collector 113 of the first terminal electrode 20.

[0068] The second edge portion 55 is located at the edge of the sealing sheet 50 opposite to the first edge portion 54. The second edge portion 55 extends from the side wall portion 51 outside in the first direction D1 of the second terminal electrode 30. The second edge portion 55 extends parallel to the first direction D1. The second edge portion 55 faces the first surface 32 of the second terminal electrode 30 in the second direction D2. The second edge portion 55 is in contact with the first surface 32 of the second terminal electrode 30. The second edge portion 55 is fused to the first surface 32 of the second terminal electrode 30. The second edge portion 55 is in contact with the first collector 112 of the second terminal electrode 30. The second edge portion 55 is fused to the first collector 112 of the second terminal electrode 30.

[0069] The sealing sheet 50 includes a resin layer 501 and a metal layer 502. The resin layer 501 is formed of a resin composition containing a hot-melt resin. In the present embodiment, the resin layer 501 contains a polypropylene-based resin such as polypropylene or modified polypropylene, or a polyethylene-based resin such as polyethylene or modified polyethylene.

[0070] The metal layer 502 is provided on the surface of the resin layer 501 opposite to the surface facing the first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30. As the metal layer 502, for example, metal foils such as Al foil, Ni foil, Cu foil, and stainless steel foil can be used. In the present embodiment, the metal layer 502 is Al foil.

[0071] The thickness of the sealing sheet 50 is not particularly limited. For example, the thickness of the sealing sheet 50 is preferably 1 mm or less. Thereby, the formation of the folded portion 52 and the folded-back portion 53 becomes easy. In addition, the total thickness in the second direction D2 of the first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30 in the power storage module 1 is, for example, 15 mm or more and 20 mm or less.

[0072] In the power storage module 1 according to the present embodiment, an internal space defined by the first terminal electrode 20, the electrode plate 10, and the sealing sheet 50, a plurality of internal spaces defined by the plurality of adjacent electrode plates 10 and the sealing sheet 50, and an internal space defined by the electrode plate 10 and the second terminal electrode 30 are formed. That is, the sealing sheet 50 seals the power storage module 1.

[0073] An electrolytic solution (not shown) may be injected into these internal spaces. An electrolytic solution may not be injected into these internal spaces. When the power storage module 1 does not include an electrolytic solution, the spacer 40 may also be a solid electrolyte.

[0074] Here, the power storage module according to the comparative example will be described. The power storage module according to the comparative example is a bipolar battery. The same structures as those of the power storage module according to the first embodiment in the power storage module according to the comparative example will not be repeatedly described.

[0075] Figure 3 It is a cross-sectional view showing a part of the power storage module according to the comparative example. As Figure 3 shown, the power storage module 9 according to the comparative example does not include the sealing sheet in the first embodiment. The power storage module 9 according to the comparative example further includes a plurality of first sealing materials 91, a plurality of spacers 92, a second sealing material 93, and an outer package 94.

[0076] A plurality of first sealing materials 91 are arranged on both sides of each electrode plate of the plurality of electrode plates 10 (current collector foils 110) in the second direction D2 of the end portion 11. A plurality of spacers 92 are respectively arranged between a pair of first sealing materials 91 arranged between the current collector foils 110 adjacent to each other in the second direction D2. In the power storage module 9 according to the comparative example, an internal space defined by the plurality of electrode plates 10 adjacent to each other, the plurality of first sealing materials 91, and the spacers 92 is formed. In other words, the plurality of first sealing materials 91 and the spacers 92 seal between the electrode plates 10. Further, since the spacer 92 has a predetermined thickness, a space for injecting an electrolytic solution into the internal space is ensured. Furthermore, the plurality of first sealing materials 91 and the spacers 92 prevent the first current collector 112 of a certain current collector foil 110 from coming into contact with the second current collector 113 of another adjacent current collector foil 110. Here, in a stacked unipolar battery different from the comparative example, there is a case where a plurality of positive electrode foils have the same potential as each other and a plurality of negative electrode foils have the same potential as each other. However, in the power storage module 9 as a bipolar battery, the plurality of current collector foils 110 must have different potentials from each other. Therefore, the plurality of first sealing materials 91 and the spacers 92 prevent a short circuit from occurring due to contact between the plurality of current collector foils 110. A part of the plurality of first sealing materials 91 and the plurality of spacers 92 is embedded in the second sealing material 93. Thereby, leakage of the electrolytic solution in the internal space to the outside of the power storage module 9 can be further suppressed. The exterior body 94 covers the outside of the second sealing material 93.

[0077] In the power storage module 9 according to the comparative example, as described above, the plurality of first sealing materials 91, the plurality of spacers 92, and the second sealing material 93 are formed of mutually independent components. In addition, it is difficult to manufacture a molded product in which these three types of multiple components are all formed integrally. Further, it is also difficult to manufacture a molded product in which a pair of first sealing materials 91 and the spacer 92 are integrated. Even if it is assumed that such a molded product can be formed, it is difficult to insert and arrange it between the current collector foils 110. In addition, when forming a molded product in which a pair of first sealing materials 91 and the spacer 92 are integrated, there is a possibility that the manufacturing cost increases.

[0078] However, as described above, in the power storage module 1 according to Embodiment 1 of the present disclosure, the sealing sheet 50 covers the end portions 11 in the first direction D1 of the current collecting foils 110 of the plurality of electrode plates 10. The sealing sheet 50 includes a plurality of side wall portions 51, a plurality of folded-in portions 52, and a folded-back portion 53. The plurality of side wall portions 51 are respectively disposed outside the current collecting foils 110 of the plurality of electrode plates 10 in the first direction D1. The plurality of folded-in portions 52 are folded in from each of the side wall portions 51 of the plurality of side wall portions toward between the plurality of electrode plates 10. The folded-back portion 53 connects the plurality of folded-in portions 52 adjacent to each other to each other between the plurality of electrode plates 10. At least a part of the plurality of folded-in portions 52 is respectively fused to the current collecting foils 110 of the corresponding plurality of electrode plates 10.

[0079] Accordingly, the sealing sheet 50 can seal between the plurality of electrode plates 10 and can function as an exterior member of the plurality of electrode plates 10. Therefore, the number of components of the power storage module 1 can be reduced. In addition, the volume ratio of the plurality of electrode plates 10 in the power storage module 1 can be increased, and the energy density of the power storage module 1 can be improved. Further, in the present embodiment, the power storage module 1 is exemplified as a bipolar battery, but even if the power storage module 1 is a unipolar battery, the same effect can be achieved by having the above-described structure.

[0080] In addition, in the present embodiment, the sealing sheet 50 includes a resin layer 501 and a metal layer 502. The metal layer 502 is provided on the surface of the resin layer 501 opposite to the surface facing the plurality of electrode plates 10. Accordingly, it is possible to suppress moisture permeation in the power storage module 1 without further providing other components different from the sealing sheet 50.

[0081] Further, it is preferable that the metal layer 502 is the outermost layer of the sealing sheet 50. Accordingly, it is possible to suppress moisture from permeating through the sealing sheet 50 and to make the thickness of the sealing sheet 50 relatively thin. By making the thickness of the sealing sheet 50 relatively thin, it is possible to make the power storage module 1 space-saving.

[0082] Furthermore, in the present embodiment, the resin layer 501 contains a polypropylene-based resin or a polyethylene-based resin. Accordingly, the water absorption rate of the resin layer 501 can be reduced.

[0083] In addition, in the present embodiment, each of the plurality of electrode plates 10 includes a first active material layer 120 coated on the current collector foil 110 and a second active material layer 130 coated on the current collector foil 110. The first active material layer 120 is located on one side of the current collector foil 110 in the second direction D2. The second active material layer 130 is located on the other side of the current collector foil 110 in the second direction D2. One of the first active material layer 120 and the second active material layer 130 is a negative electrode active material layer, and the other is a positive electrode active material layer. The plurality of spacers 40 are respectively disposed between the mutually adjacent first active material layer 120 and second active material layer 130.

[0084] According to the above structure, each of the plurality of electrode plates 10 becomes a bipolar electrode, and the power storage module 1 becomes a bipolar battery. In the power storage module 1 as a bipolar battery, the potentials of the plurality of current collector foils 110 are different from each other. In order to suppress the occurrence of a short circuit, it is important to suppress the plurality of current collector foils 110 from contacting each other. In order to suppress the current collector foils 110 from contacting each other, in the comparative example, a plurality of first sealing materials 91, a plurality of spacers 92, a second sealing material 93 for fixing them, and an exterior body 94 covering the second sealing material 93 are provided. However, according to the above structure in the present embodiment, a plurality of folded portions 52 and folded-back portions 53 are formed by one sealing sheet 50 to suppress the current collector foils 110 from contacting each other. Further, as described above, the sealing sheet 50 also functions as an exterior member. Therefore, when the power storage module 1 in the present embodiment is a bipolar battery, the number of components can be made very small compared to the bipolar battery in the comparative example.

[0085] Next, a method for manufacturing the power storage module 1 according to Embodiment 1 of the present disclosure will be described. Figure 4 It is a flowchart showing a method for manufacturing the power storage module according to Embodiment 1 of the present disclosure. As Figures 1 - 4 shown, the method for manufacturing the power storage module according to Embodiment 1 of the present disclosure sequentially includes: Step S1 of covering the end portion 21 of the first terminal electrode 20 with the sealing sheet 50; Step S2 of laminating the plurality of electrode plates 10 on the first terminal electrode 20 and covering the end portions 11 of the plurality of electrode plates 10 (current collector foils 110) with the sealing sheet 50; and Step S3 of laminating the second terminal electrode 30 on the electrode plates 10 and covering the end portion 31 of the second terminal electrode 30 with the sealing sheet 50.

[0086] First, Step S1 will be described. Figure 5 It is a flowchart showing Step S1 of the method for manufacturing the power storage module. Figures 6A - 6E It is a schematic cross-sectional view schematically showing the process of Step S1.

[0087] As Figure 5 and Figure 6AAs shown, in step S1, first, the first terminal electrode 20 is prepared (step S10). Moreover, the spacer 40 is disposed on one surface (the first surface 22) of the first terminal electrode 20 (step S11).

[0088] Next, as Figure 5 , Figure 6A and Figure 6B shown, the sealing sheet 50 is fused to a part of the other surface (the second surface 23) of the first terminal electrode 20 (step S12). Specifically, the first edge portion 54 of the sealing sheet 50 is fused to the second surface 23 of the end portion 21 of the first terminal electrode 20. The end portion 21 of the first terminal electrode 20 and the first edge portion 54 of the sealing sheet 50 are heated from both sides in the second direction D2 and clamped by a pair of heaters 6. Thereby, the surface of the resin layer 501 of the first edge portion 54 is melted and heat-fused to the first terminal electrode 20.

[0089] Next, as Figure 5 , Figure 6B and Figure 6C shown, the sealing sheet 50 is folded from the other surface (the second surface 23) side of the first terminal electrode 20 so as to cover the end portion 21 of the first terminal electrode 20 and a part of the one surface (the first surface 22) of the first terminal electrode 20 (step S13). Thereby, a side wall portion 51 is formed on the outside of the first terminal electrode 20 in the first direction D1. Further, a folded-in portion 52 is formed on the first surface 22 side of the first terminal electrode 20.

[0090] Next, as Figure 5 , Figure 6C and Figure 6D shown, the sealing sheet 50 is fused to a part of the one surface (the first surface 22) of the first terminal electrode 20 (step S14). Specifically, the folded-in sealing sheet 50 (the folded-in portion 52) is fused to the first surface 22 of the end portion 21 of the first terminal electrode 20. The end portion 21 of the first terminal electrode 20 and the folded-in portion 52 are heated from both sides in the second direction D2 together with the first edge portion 54 and clamped. Thereby, the surface of the resin layer 501 of the folded-in portion 52 is melted and heat-fused to the first terminal electrode 20.

[0091] At the end of step S1, as Figure 5 , Figure 6D and Figure 6E shown, the sealing sheet 50 is turned back on the one surface (the first surface 22) side of the first terminal electrode 20 (step S15). Thereby, the sealing sheet 50 extends outward from the first terminal electrode 20 in the first direction D1. Specifically, the vicinity of the inside of the portion of the folded-in sealing sheet 50 that is fused to the first surface 22 of the first terminal electrode 20 is turned back.

[0092] Thus, in the present embodiment, step S1 successively includes steps S10 to S15. However, the order of steps S10 to S15 is not limited to the above.

[0093] Next, step S2 will be described. In step S2, a series of steps are repeated. Therefore, hereinafter, steps included in a part of step S2 will be described.

[0094] Figure 7 It is a flowchart showing a part of step S2 of the manufacturing method of the power storage module. Figures 8A - 8F It is a schematic cross-sectional view showing a part of the flow of step S2.

[0095] A step of covering the end portion 11 of the first electrode plate 10A (collecting foil 110) with the sealing sheet 50 for the electrode plate 10 will be described. First, as Figure 7 and Figure 8A shown, the first electrode plate 10A is prepared (step S20A). And, the first spacer 40A is disposed on one surface (first surface 12) of the first electrode plate 10A (step S21A).

[0096] Next, as Figure 7 , Figure 8A and Figure 8B shown, the folded-back sealing sheet 50 is fused to a part of the other surface (second surface 13) of the first electrode plate 10A (step S22A). Specifically, a part of the folded-back sealing sheet 50 is fused to the second surface 13 of the end portion 11 of the first electrode plate 10A (collecting foil 110). The end portion 11 of the first electrode plate 10A (collecting foil 110) and a part of the folded-back sealing sheet 50 are heated from both sides in the second direction D2 and clamped by a pair of heaters 6. Thereby, the surface of the resin layer 501 of the folded-back sealing sheet 50 is melted and heat-fused to the first electrode plate 10A.

[0097] The above-mentioned folded-back sealing sheet 50 is a sealing sheet 50 having a folded-in portion 52 fused to the first surface 12 of another electrode plate 10 different from the first electrode plate 10A. In addition, when the first electrode plate 10A is an electrode plate 10 adjacent to the first terminal electrode 20, the above-mentioned folded-back sealing sheet 50 may be a sealing sheet 50 having a folded-in portion 52 fused to the first surface 22 of the first terminal electrode 20.

[0098] Next, as Figure 7 , Figure 8B and Figure 8CAs shown, the sealing sheet 50 is folded from the other surface (second surface 13) side of the first electrode plate 10A so as to cover the end portion 11 of the first electrode plate 10A (current collecting foil 110) and a part of one surface (first surface 12) of the first electrode plate 10A (step S23A). Thereby, an inserted portion 52 is formed on the second surface 13 side of the first electrode plate 10A. Moreover, a side wall portion 51 is formed on the outer side in the first direction D1 of the first electrode plate 10A. Further, an inserted portion 52 is also formed on the first surface 12 side of the first electrode plate 10A.

[0099] Next, as Figure 7 , Figure 8C and Figure 8D shown, the sealing sheet 50 is fused to a part of one surface (first surface 12) of the first electrode plate 10A (step S24A). Specifically, the folded sealing sheet 50 (inserted portion 52) is fused to the first surface 12 of the end portion 11 of the first electrode plate 10A (current collecting foil 110). The folded portion 52 on the second surface 13 and the end portion 11 of the first electrode plate 10A (current collecting foil 110) are heated from both sides in the second direction D2 by a pair of heaters 6 and clamped. Thereby, the surface of the resin layer 501 of the inserted portion 52 on the first surface 12 is melted and heat-fused to the first electrode plate 10A.

[0100] Next, as Figure 7 , Figure 8D and Figure 8E shown, the first electrode plate 10A is disposed on the spacer 40 of the other electrode plate 10 (step S25A). Specifically, the second active material layer 130 of the first electrode plate 10A is disposed on the other spacer 40 of the other electrode plate 10. And the inserted portion 52 disposed on the second surface 13 of the first electrode plate 10A is disposed on the inserted portion 52 disposed on the first surface 12 of the other electrode plate 10. Thereby, a folded-back portion 53 connecting these inserted portions 52 to each other is formed between the first electrode plate 10A and the other electrode plate 10. In addition, even when the first electrode plate 10A is an electrode plate 10 adjacent to the first terminal electrode 20, similarly, a folded-back portion 53 is formed between the first electrode plate 10A and the first terminal electrode 20.

[0101] Next, as Figure 7 , Figure 8E and Figure 8F shown, the sealing sheet 50 is folded back on the one surface (first surface 12) side of the first electrode plate 10A (step S26A). Thereby, the sealing sheet 50 extends outward from the first electrode plate 10A in the first direction D1. Specifically, the vicinity of the inside of the portion of the folded sealing sheet 50 that is fused to the first surface 12 of the first electrode plate 10A is folded back.

[0102] Thus, in the present embodiment, step S2 successively includes steps S20A to S26A. In steps S20A to S26A, the first electrode plate 10A is stacked on the other electrode plates 10 with the spacer 40 interposed therebetween, and the end portion 11 of the first electrode plate 10A (collecting foil 110) is covered with a sealing sheet material. However, the order of steps S20A to S26A is not limited to the above.

[0103] In step S2, the above steps S20A to S26A are repeated by the number of the electrode plates 10. Figures 9A - 9F schematically shows Figures 8A - 8F a continuation of a part of the process of step S2 shown. For example, as Figure 7 and Figures 9A - 9F shown, in steps S20B to S26B, the second electrode plate 10B is stacked on the first electrode plate 10A with the first spacer 40A interposed therebetween, and the end portion 11 of the second electrode plate 10B (collecting foil 110) is covered with a sealing sheet material 50. Steps S20B to S26B can be implemented by replacing the other electrode plates 10 and the first electrode plate 10A and the other spacer 40 and the first spacer 40A in steps S20A to S26A with the first electrode plate 10A and the second electrode plate 10B and the first spacer 40A and the second spacer 40B, respectively.

[0104] Thus, as Figure 7 , Figures 8A - 8F and Figures 9A - 9FAs shown, the manufacturing method of the power storage module 1 according to the embodiments of the present disclosure includes: disposing a first spacer 40A on the active material layer on one side (the first surface 12) of the first electrode plate 10A including a current collector foil 110 and at least one active material layer coated on the current collector foil (step S21A); folding the sealing sheet 50 from the other side (the second surface 13) of the current collector foil 110 of the first electrode plate 10A so that the sealing sheet 50 covers the end portion 11 of the current collector foil 110 of the first electrode plate 10A and a part of one side (the first surface 12) of the current collector foil 110 of the first electrode plate 10A (step S23A); fusing the sealing sheet 50 to a part of one side (the first surface 12) of the current collector foil 110 of the first electrode plate 10A (step S24A); turning back the sealing sheet 50 on the side of the first surface 12 of the current collector foil 110 of the first electrode plate 10A (step S26A); fusing the turned-back sealing sheet 50 to a part of the other side (the second surface 13) of the current collector foil 110 of the second electrode plate 10B, which is opposite to one side (the first surface 12), in the second electrode plate 10B including the current collector foil 110 and at least one active material layer coated on the current collector foil (step S22B); folding the sealing sheet 50 from the other side (the second surface 13) of the current collector foil 110 of the second electrode plate 10B so that the turned-back sealing sheet 50 covers the end portion 11 of the current collector foil 110 of the second electrode plate 10B and a part of one side (the first surface 12) of the current collector foil 110 of the second electrode plate 10B (step S23B); and disposing the active material layer of the second electrode plate 10B on the first spacer 40A (step S25B).

[0105] Thereby, the sealing sheet 50 can seal between the current collector foil 110 of the first electrode plate 10A and the current collector foil 110 of the second electrode plate 10B, and can function as an exterior member of the first electrode plate 10A and the second electrode plate 10B. Therefore, the number of components of the power storage module 1 can be reduced. Even more, the structure of the power storage module 1 can be simplified. Furthermore, according to the above structure, the current collector foil 110 of the first electrode plate 10A and the current collector foil 110 of the second electrode plate 10B can be sealed by the relatively thin sealing sheet 50, so the volume ratio of the first electrode plate 10A and the second electrode plate 10B in the power storage module 1 can be increased, and the energy density of the power storage module 1 can be improved.

[0106] In addition, the step of disposing the active material layer of the second electrode plate 10B on the first spacer 40A (step S25B) is performed after the step of fusing the sealing sheet 50 to a part of one side (the first surface 12) of the current collector foil 110 of the first electrode plate 10A (step S24A) and after the step of fusing the turned-back sealing sheet 50 to a part of the other side (the second surface 13) of the current collector foil 110 of the second electrode plate 10B (step S22B).

[0107] Thus, it is possible to fuse the sealing sheet 50 in the process of laminating the first electrode plate 10A, the spacer 40, and the second electrode plate 10B to each other. Moreover, it is possible to reduce the number of manufacturing processes of the power storage module 1.

[0108] Finally, step S3 will be described. Figure 10 FIG. is a flowchart of step S3 of a method for manufacturing a power storage module. Figures 11A - 11E FIG. is a schematic cross-sectional view schematically showing the flow of step S3.

[0109] As Figure 10 and Figure 11A shown, first, the second terminal electrode 30 is prepared (step S30). Next, as Figure 10 , Figure 11A and Figure 11B shown, a folded-back sealing sheet 50 is fused to a part of the other surface (second surface 33) of the second terminal electrode 30 (step S31). Specifically, a part of the folded-back sealing sheet 50 is fused to the second surface 33 of the end portion 31 of the second terminal electrode 30. The end portion 31 of the second terminal electrode 30 and a part of the folded-back sealing sheet 50 are heated from both sides in the second direction D2 and clamped by a pair of heaters 6. As a result, the surface of the resin layer 501 of the folded-back sealing sheet 50 melts and is heat-fused to the second terminal electrode 30. The above-mentioned folded-back sealing sheet 50 is a sealing sheet 50 formed with a folded-in portion 52 by being fused to the first surface 12 of the electrode plate 10 adjacent to the second terminal electrode 30.

[0110] Next, as Figure 10 , Figure 11B and Figure 11C shown, the sealing sheet 50 is folded from the side of the other surface (second surface 33) of the second terminal electrode 30 so as to cover the end portion 31 of the second terminal electrode 30 and a part of one surface (first surface 32) of the second terminal electrode 30 (step S32). As a result, a folded-in portion 52 is formed on the second surface 13 side of the second terminal electrode 30. Moreover, a side wall portion 51 is formed on the outer side in the first direction D1 of the second terminal electrode 30. Further, the second edge portion 55 of the sealing sheet 50 is disposed on the first surface 32 side of the second terminal electrode 30.

[0111] Next, as Figure 10 , Figure 11C and Figure 11DAs shown, the sealing sheet 50 is fused to a part of one surface (the first surface 32) of the second terminal electrode 30 (step S33). Specifically, the second edge portion 55 of the sealing sheet 50 is fused to the end portion 31 of the second terminal electrode 30 on the first surface 32. The end portion 31 of the second terminal electrode 30 and the second edge portion 55 on the first surface 32 are heated from both sides in the second direction D2 together with the folded portion 52 on the second surface 33 by a pair of heaters 6 and clamped. As a result, the surface of the resin layer 501 of the second edge portion 55 on the first surface 32 melts and is thermally fused to the second terminal electrode 30.

[0112] Finally, as shown in Figure 10 , Figure 11D and Figure 11E shown, the second terminal electrode 30 is disposed on the spacer 40 of the electrode plate 10 (step S34). Specifically, the second active material layer 130 of the second terminal electrode 30 is disposed on the spacer 40 of the electrode plate 10 adjacent to the second terminal electrode 30. And, the folded portion 52 disposed on the second surface 33 of the second terminal electrode 30 is disposed on the folded portion 52 disposed on the first surface 12 of the electrode plate 10 adjacent to the second terminal electrode 30. As a result, a folded-back portion 53 connecting these folded portions 52 to each other is formed between the second terminal electrode 30 and the electrode plate 10.

[0113] Thus, in the present embodiment, step S3 sequentially includes steps S30 to S34. However, the order of steps S30 to S34 is not limited to the above.

[0114] Through steps S1, S2, and S3 described above, the power storage module according to Embodiment 1 of the present disclosure can be manufactured.

[0115] (Embodiment 2)

[0116] Next, the power storage module according to Embodiment 2 of the present disclosure will be described. In the power storage module according to Embodiment 2, the structure of the plurality of folded-back portions is different from that of the power storage module according to Embodiment 1. In addition, the same structures and effects as those of the power storage module according to Embodiment 1 will not be repeatedly described.

[0117] Figure 12 is a cross-sectional view showing a part of the power storage module according to Embodiment 2 of the present disclosure. In Figure 12 , the power storage module is illustrated in the same cross-sectional view as Figure 2 in Embodiment 1.

[0118] As shown in Figure 12As shown, in the power storage module 1a according to Embodiment 2 of the present disclosure, a groove portion 56a is formed in the resin layer 501 of at least one folded-back portion 53a. Thereby, the stress of the folded-back portion 53 of the sealing sheet 50 can be alleviated.

[0119] The groove portion 56a may be formed in any folded-back portion 53a. One or more groove portions 56a may be respectively formed in one or more folded-back portions 53a located between the electrode plates 10. The groove portion 56a may be formed in the folded-back portion 53a located between the first terminal electrode 20 and the adjacent electrode plate 10. The groove portion 56a may be formed in the folded-back portion 53a located between the second terminal electrode 30 and the adjacent electrode plate 10. In the present embodiment, the groove portion 56a is formed in all the folded-back portions 53a.

[0120] The groove portion 56a may also be Figure 12 extending in the direction orthogonal to the paper surface (i.e., the direction orthogonal to the first direction D1 and the second direction D2). The groove portion 56a is formed in the resin layer 501. The metal layer 502 may also be exposed in the groove portion 56a. The resin layer 501 may be divided into a plurality of portions via the groove portion 56a.

[0121] (Embodiment 3)

[0122] Next, the power storage module according to Embodiment 3 of the present disclosure will be described. In the power storage module according to Embodiment 3, the structure of the sealing sheet is different from that of the power storage module according to Embodiment 1. In addition, the same structures and effects as those of the power storage module according to Embodiment 1 will not be repeatedly described.

[0123] Figure 13 is a cross-sectional view showing a part of the power storage module according to Embodiment 3 of the present disclosure. In Figure 13 it, the power storage module is illustrated in the same cross-sectional view as that in Embodiment 1. Figure 2 is the same cross-sectional view as that in Embodiment 1.

[0124] As Figure 13 shown, in the power storage module 1b according to Embodiment 3 of the present disclosure, the sealing sheet 50b further includes an outer resin layer 503b. The outer resin layer 503b is provided on the surface of the metal layer 502b opposite to the surface in contact with the resin layer 501b. Thereby, the outside of the metal layer 502b can be easily insulated.

[0125] Between the plurality of electrode plates 10, at least a part of the outer resin layers 503b of the plurality of folded-in portions 52b (a pair of folded-in portions 52b) are fused to each other. Thereby, the shape of the sealing sheet 50b can be maintained more firmly.

[0126] In addition, in the manufacturing method of the power storage module 1b according to the present embodiment, in the same manner as steps S1 to S3 in the manufacturing method of the power storage module according to Embodiment 1, after covering each of the end portions 21, 11, and 31 with the sealing sheet 50b, a plurality of pairs of folded portions 52b are heated. As a result, the outer resin layers 503b of the respective pairs of folded portions 52b are heat-fused to each other. At this time, the pairs of folded portions 52b can be heated from the side opposite to the side of the folded-back portion 53.

[0127] In the description of the above embodiments, structures that can be combined may be combined with each other.

[0128] Embodiments of the present invention have been described, but it should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown by the claims, and it is intended to include meanings equivalent to the claims and all modifications within the scope.

Claims

1. A power storage module, comprising: a plurality of electrode plates; a plurality of separators; and a sealing sheet, each of the plurality of electrode plates includes a current collector foil and at least one active material layer coated on the current collector foil, the plane direction of each of the plurality of electrode plates extends along a first direction, the plurality of electrode plates are arranged adjacent to each other in a second direction orthogonal to the first direction, the plurality of separators are respectively disposed between the active material layers of the plurality of electrode plates adjacent to each other, the sealing sheet covers the end portions of the current collector foils of the plurality of electrode plates in the first direction, the sealing sheet includes: a plurality of side wall portions respectively disposed outside the current collector foils of the plurality of electrode plates in the first direction; a plurality of folded-in portions folded from each of the plurality of side wall portions toward between the plurality of electrode plates; and a folded-back portion connecting the plurality of folded-in portions adjacent to each other between the plurality of electrode plates, at least a part of the plurality of folded-in portions is fused to the current collector foils of the corresponding plurality of electrode plates respectively.

2. The power storage module according to claim 1, wherein the sealing sheet includes a resin layer and a metal layer provided on a surface of the resin layer opposite to the surface facing the plurality of electrode plates.

3. The power storage module according to claim 2, wherein the resin layer contains a polypropylene-based resin or a polyethylene-based resin.

4. The power storage module according to claim 2 or 3, wherein a groove portion is formed in the resin layer of the folded-back portion.

5. The power storage module according to claim 2 or 3, wherein the sealing sheet further includes an outer resin layer provided on a surface of the metal layer opposite to the surface in contact with the resin layer.

6. The power storage module according to claim 5, wherein at least a part of the outer resin layers of the plurality of folded-in portions is fused to each other between the plurality of electrode plates.

7. The power storage module according to claim 1, wherein each of the plurality of electrode plates includes a first active material layer coated on the current collector foil and a second active material layer coated on the current collector foil, the first active material layer is located on one side of the current collector foil in the second direction, the second active material layer is located on the other side of the current collector foil in the second direction, one of the first active material layer and the second active material layer is a negative electrode active material layer and the other is a positive electrode active material layer, the plurality of separators are respectively disposed between the first active material layer and the second active material layer adjacent to each other.

8. The power storage module according to claim 1, wherein the power storage module is a power storage module including bipolar batteries.

9. A method for manufacturing a power storage module, comprising: disposing a separator on the active material layer on one side of a first electrode plate, the first electrode plate including a current collector foil and at least one active material layer coated on the current collector foil; Fold the sealing sheet from the other side of the current collector foil of the first electrode plate in such a manner that the sealing sheet covers the end portion of the current collector foil of the first electrode plate and a part of one surface of the current collector foil of the first electrode plate; Fuse the sealing sheet to a part of one surface of the current collector foil of the first electrode plate; Turn back the sealing sheet on one surface side of the current collector foil of the first electrode plate; Fuse the turned-back sealing sheet to a part of the other surface, opposite to one surface, of the current collector foil in the second electrode plate, the second electrode plate including a current collector foil and at least one active material layer coated on the current collector foil; Fold the sealing sheet from the other side of the current collector foil of the second electrode plate in such a manner that the turned-back sealing sheet covers the end portion of the current collector foil of the second electrode plate and a part of one surface of the current collector foil of the second electrode plate; and Dispose the active material layer of the second electrode plate on the spacer.

10. The method for manufacturing an electric storage module according to claim 9, wherein the step of disposing the active material layer of the second electrode plate on the spacer is performed after the step of fusing the sealing sheet to a part of one surface of the current collector foil of the first electrode plate and after the step of fusing the turned-back sealing sheet to a part of the other surface of the current collector foil of the second electrode plate.

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