Power storage module and manufacturing method thereof

Abstract

To simplify the structure of a power storage module and improve the energy density of the power storage module.SOLUTION: In a power storage module according to the present disclosure, a sealing sheet 50 covers the ends 11 of the current collecting foils 110 of multiple electrode plates 10 in the first direction D1. The sealing sheet 50 includes multiple side wall portions 51, multiple folded portions 52, and a folded-back portion 53. The multiple side wall portions 51 are respectively disposed on the outer sides of the current collecting foils 110 of the multiple electrode plates 10 in the first direction D1. The multiple folded portions 52 are folded from each of the multiple side wall portions 51 toward the spaces between the multiple electrode plates 10. The folded-back portion 53 connects adjacent folded portions 52 between the multiple electrode plates 10. At least a portion of the multiple folded portions 52 is welded to the current collecting foils 110 of the corresponding multiple electrode plates 10.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-91606) discloses a power storage device including a plurality of bipolar batteries. The bipolar battery includes an electrode laminate and a seal frame. The electrode laminate is formed by laminating a plurality of bipolar electrodes with a separator interposed therebetween. The bipolar electrode has a nickel foil, a positive electrode, and a negative electrode. The seal frame is disposed so as to surround the electrode laminate. The seal frame has a plurality of primary seal portions and a secondary seal portion. The plurality of primary seal portions each hold an edge portion of each nickel foil. An internal space defined by the nickel foil, the positive electrode, the negative electrode, and the primary seal portion is provided between adjacent nickel foils in the stacking direction. The primary seal portion seals the internal space. The secondary seal portion surrounds each primary seal portion and further seals the internal space.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power storage device including a conventional power storage module, the space between electrode plates is sealed with a plurality of seal members. For this reason, in the power storage module, the number of components increases due to these seal members, and the structure of the power storage module is complicated. In addition, since there is a limit to reducing the size of each seal member, the space efficiency may deteriorate, and it has been difficult to increase the energy density of the power storage module.

[0005] The present disclosure has been made in view of the above problems, and aims to simplify the structure of the power storage module by reducing the number of components in the power storage module, and to enhance the possibility of providing a power storage module with a high energy density.

Means for Solving the Problems

[0006] The power storage module according to the first aspect of the present disclosure includes 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 surface direction of each of the plurality of electrode plates extends along a first direction. The plurality of electrode plates are arranged side by side with 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 adjacent electrode plates. The sealing sheet covers the ends 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 welded to the current collector foils of the corresponding plurality of electrode plates respectively.

[0007] Thereby, the sealing sheet can seal between the plurality of electrode plates and can function as an exterior material for the plurality of electrode plates. Therefore, the number of components of the power storage module can be reduced. As a result, the structure of the power storage module can be simplified. Further, according to the above configuration, since the relatively thin sealing sheet can seal between the current collector foils, the volume ratio of the plurality of electrode plates in the power storage module can be increased, and the energy density of the power storage module can be improved.

[0008] In the above-described power storage module, the sealing sheet may include a resin layer and a metal layer. The metal layer may be provided on a surface of the resin layer opposite to the surface facing the plurality of electrode plates. Thereby, moisture permeation in the power storage module can be suppressed without further providing another member different from the sealing sheet.

[0009] In the above-described power storage module, the resin layer may include a polypropylene-based resin or a polyethylene-based resin. Thereby, the water absorption rate of the resin layer can be lowered.

[0010] In the above-described power storage module, a groove portion may be formed in the resin layer of the folded portion. Thereby, the stress at the folded portion of the sealing sheet can be relaxed.

[0011] In the above-described power storage module, the sealing sheet may further include an outer resin layer. The outer resin layer may be provided on a surface of the metal layer opposite to the surface in contact with the resin layer. Thereby, the outside of the metal layer can be easily insulated.

[0012] In the above-described power storage module, between the plurality of electrode plates, at least a part of the outer resin layers of the plurality of folded portions may be welded to each other. Thereby, the shape of the sealing sheet can be maintained more firmly.

[0013] In the above-described power storage module, each of the plurality of electrode plates may include a first active material layer applied to a current collector foil and a second active material layer applied to 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. The plurality of separators may be respectively disposed between the first active material layer and the second active material layer adjacent to each other.

[0014] As a result, 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 which is a bipolar battery, the potentials of the plurality of current collector foils 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 from coming into contact with each other. Here, according to the above-described power storage module, by forming a plurality of folded portions and folded-back portions in one sealing sheet, contact between the current collector foils can be suppressed. Furthermore, as described above, the sealing sheet can also function as an exterior material. Therefore, when the power storage module is a bipolar battery, the number of components can be made extremely small compared to a conventional bipolar battery.

[0015] The above-described power storage module may be a power storage module composed of a bipolar type battery.

[0016] In a power storage module composed of a bipolar type battery, the potentials of the plurality of current collector foils 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 from coming into contact with each other. Here, according to the above-described power storage module, by forming a plurality of folded portions and folded-back portions in one sealing sheet, contact between the current collector foils can be suppressed. Furthermore, as described above, the sealing sheet can also function as an exterior material. Therefore, the number of components can be made extremely small compared to a conventional bipolar type battery.

[0017] The method for manufacturing an energy storage module according to the second aspect of the present disclosure includes arranging a separator on the active material layer located on one surface side of a first electrode plate including a current collector foil and at least one active material layer applied to the current collector foil; folding a sealing sheet from the other surface side of the current collector foil of the first electrode plate so that the sealing sheet covers the end of the current collector foil of the first electrode plate and a part of one surface of the first electrode plate; welding the sealing sheet to a part of the current collector foil on one surface of the first electrode plate; folding back the sealing sheet on one surface side of the current collector foil of the first electrode plate; welding the folded-back sealing sheet to a part of the other surface of the current collector foil in a second electrode plate including a current collector foil and at least one active material layer applied to the current collector foil, which is opposite to one surface; folding the sealing sheet from the other surface side of the current collector foil of the second electrode plate so that the folded-back sealing sheet covers the end 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 arranging the active material layer of the second electrode plate on the separator.

[0018] Thereby, 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 material for the first electrode plate and the second electrode plate. Therefore, the number of members of the energy storage module can be reduced. As a result, the structure of the energy storage module can be simplified. Further, according to the above configuration, since the relatively thin sealing sheet 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 energy storage module can be increased, and the energy density of the energy storage module can be improved.

[0019] In the above method for manufacturing an energy storage module, arranging the active material layer of the second electrode plate on the separator may be performed after welding the sealing sheet to a part of one surface of the current collector foil of the first electrode plate and after welding the folded-back sealing sheet to a part of the other surface of the current collector foil of the second electrode plate.

[0020] Thereby, the sealing sheet can be welded in the process of laminating the first electrode plate, the separator, and the second electrode plate to each other. As a result, the number of manufacturing steps of the energy storage module can be reduced.

Advantages of the Invention

[0021] According to the present disclosure, the number of components in the power storage module can be relatively reduced, and the structure of the power storage module can be simplified. In addition, the possibility of providing a power storage module with a high energy density can be enhanced.

Brief Description of the Drawings

[0022]

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Mode for Carrying Out the Invention

[0023] Hereinafter, the power storage module according to each embodiment of the present disclosure will be described with reference to the drawings. 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.

[0024] (Embodiment 1) FIG. 1 is a perspective view schematically showing a power storage module according to Embodiment 1 of the present disclosure. FIG. 2 is a cross-sectional view of a part of the power storage module of FIG. 1 as viewed from the direction of the arrow II-II.

[0025] As shown in FIGS. 1 and 2, 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 separators 40, and a sealing sheet 50.

[0026] 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 may be used as the exterior of the secondary battery. Either one of the first terminal electrode 20 and the second terminal electrode 30 may be the positive electrode external terminal of the secondary battery, and the other may be the negative electrode external terminal. The power storage module 1 is provided so that current can be taken out from the first terminal electrode 20 and the second terminal electrode 30 to the outside.

[0027] The plane direction of each of the plurality of electrode plates 10 is along the first direction D1. The plurality of electrode plates 10 are arranged side by side with each other in a second direction D2 orthogonal to the first direction D1. The electrode plate 10 has, for example, a rectangular outer shape when viewed from the second direction D2.

[0028] 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 in the second direction D2. The second surface 13 is located on the other side in the second direction D2.

[0029] The electrode plate 10 is, for example, a bipolar electrode. Therefore, in this 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.

[0030] 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.

[0031] 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. Note that the current collector foil 110 may be composed of a single member.

[0032] The current collector foil 110 (each of the first current collector 112 and the second current collector 113) may contain at least one selected from the group consisting of, for example, 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 be a metal foil with a plating process applied to its surface.

[0033] It is sufficient that one of the first current collector 112 and the second current collector 113 is a negative electrode current collector and the other is a positive electrode current collector. In this 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).

[0034] 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, the first active material layer 120 is formed by coating the first active material on the first current collector 112.

[0035] 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, the second active material layer 130 is formed by coating the second active material on the second current collector 113.

[0036] For the first active material layer 120 and the second active material layer 130, one of them may be the negative electrode active material layer and the other may be the positive electrode active material layer. For the first active material and the second active material, one of them may be the negative electrode active material and the other may be the positive electrode active material. In this embodiment, the first active material layer 120 is the negative electrode active material layer, the first active material is the negative electrode active material, the second active material layer 130 is the positive electrode active material layer, and the second active material is the positive electrode active material.

[0037] 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 adopted.

[0038] As the positive electrode active material, for example, those capable of occluding and releasing charge carriers such as lithium ions can be adopted. Specifically, as the positive electrode active material, a lithium ion composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, a polyanion-based compound, etc., which can be used as the positive electrode active material of a lithium ion secondary battery, can be adopted. Also, two or more positive electrode active materials may be used in combination. For example, the positive electrode active material may contain olivine-type lithium iron phosphate (LiFePO4).

[0039] 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 electrode plate 10 has a first surface 22 and a second surface 23. The first surface 22 is located on one side in the second direction D2. The second surface 23 is located on the other side in the second direction D2.

[0040] 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 have the same configuration as each of the current collector foil 110 and the first active material layer 120 of the electrode plate 10 can 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 configuration as each of the current collector foil 110 and the first active material layer 120 of the electrode plate 10.

[0041] In the first terminal electrode 20, the current collector foil 110 (the second current collector 113) forms the entire second surface 23 of the first terminal electrode 20. The first terminal electrode 20 is located further outside the plurality of electrode plates 10 in the second direction D2. A plurality of electrode plates 10 are located on the first surface 22 side of the first terminal electrode 20.

[0042] 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 in the second direction D2. The second surface 33 is located on the other side in the second direction D2.

[0043] 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 have the same configuration as the configurations 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 configuration as those of the current collector foil 110 and the second active material layer 130 of the electrode plate 10 respectively.

[0044] In the second terminal electrode 30, the current collector foil 110 (the first current collector 112) forms all of the first surface 32 of the second terminal electrode 30. The second terminal electrode 30 is located further outside the plurality of electrode plates 10 in the second direction D2. The plurality of electrode plates 10 are located on the second surface 33 side of the second terminal electrode 30.

[0045] The first terminal electrode 20 and the second terminal electrode 30 may be such that one of them is a negative terminal electrode and the other is 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.

[0046] The plurality of separators 40 are respectively disposed between the 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 via the separator 40 in the second direction D2.

[0047] The separator 40 is disposed between the active material layers adjacent to each other in the second direction D2. More specifically, the separator 40 is in contact with both the first active material layer 120 and the second active material layer 130 adjacent to each other in the second direction D2. The separator 40 may be welded to either one of the two current collector foils 110 adjacent to each other in the second direction D2. When viewed from the electrode plate 10 or the first terminal electrode 20, the separator 40 located on the first surface 12, 22 side is welded to the current collector foil 110 of the electrode plate 10 or the first terminal electrode 20. That is, the separator 40 is welded to the adjacent first current collector 112.

[0048] The separator 40 is formed in a sheet shape. Examples of the separator 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, or the like. The separator 40 may be reinforced with a vinylidene fluoride resin compound.

[0049] The sealing sheet 50 covers the respective ends 21, 11, 31 in the first direction D1 of the first terminal electrode 20, the plurality of electrode plates 10, and the second terminal electrode 30. The sealing sheet 50 includes a plurality of side wall portions 51, a plurality of folding portions 52, a plurality of folded-back portions 53, a first edge portion 54, and a second edge portion 55.

[0050] 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, 31 of the first terminal electrode 20, the plurality of electrode plates 10, or the second terminal electrode 30 adjacent to each other in the first direction D1. Specifically, the side wall portion 51 is in contact with the ends 21, 11, 31. The side wall portion 51 may not be in contact with the ends 21, 11, 31.

[0051] The plurality of folding portions 52 are folded 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 adjacent electrode plates 10, and between the electrode plate 10 and the second terminal electrode 30. Each of the plurality of folding portions 52 extends parallel to the first direction D1.

[0052] Between the first terminal electrode 20 and the electrode plate 10, between the plurality of adjacent electrode plates 10, and between the electrode plate 10 and the second terminal electrode 30, a pair of folding portions 52 are respectively located. The pair of folding portions 52 are arranged in the second direction D2. The pair of folding portions 52 may be in contact with each other or separated from each other. In the present embodiment, the pair of folding portions 52 are in contact with each other.

[0053] The plurality of folding portions 52 are respectively welded to the corresponding plurality of electrode plates 10. Specifically, the folding portion 52 facing the first surface 12, 22 of the electrode plate 10 or the first terminal electrode 20 is welded to the first surface 12, 22 of the current collecting foil 110 (first current collecting body 112) among the first surfaces 12, 22 of the electrode plate 10 or the first terminal electrode 20. The folding portion 52 facing the second surface 13, 23 of the electrode plate 10 or the second terminal electrode 30 is welded to the second surface 13, 23 of the current collecting foil 110 (second current collecting body 113) among the second surfaces 13, 23 of the electrode plate 10 or the second terminal electrode 30.

[0054] The plurality of folding-back portions 53 connect the plurality of adjacent folding portions 52 to each other between the first terminal electrode 20 and the electrode plate 10, between the plurality of adjacent electrode plates 10, and between the electrode plate 10 and the second terminal electrode 30. That is, the folding-back portion 53 connects the pair of folding portions 52 to each other.

[0055] The first edge portion 54 is located at one edge of the sealing sheet 50. The first edge portion 54 extends from a side wall portion 51 located outside the first terminal electrode 20 in the first direction D1. 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 welded to the second surface 23 of the first terminal electrode 20. The first edge portion 54 is in contact with the second current collector 113 of the first terminal electrode 20. The first edge portion 54 is welded to the second current collector 113 of the first terminal electrode 20.

[0056] The second edge portion 55 is located at an edge opposite to the first edge portion 54 of the sealing sheet 50. The second edge portion 55 extends from a side wall portion 51 located outside the second terminal electrode 30 in the first direction D1. 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 welded to the first surface 32 of the second terminal electrode 30. The second edge portion 55 is in contact with the first current collector 112 of the second terminal electrode 30. The second edge portion 55 is welded to the first current collector 112 of the second terminal electrode 30.

[0057] 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 heat-sealable 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.

[0058] The metal layer 502 is provided on a 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, a metal foil such as Al foil, Ni foil, Cu foil, or stainless steel foil can be used. In the present embodiment, the metal layer 502 is Al foil.

[0059] The thickness of the sealing sheet 50 is not particularly limited. The thickness of the sealing sheet 50 is preferably, for example, 1 mm or less. This facilitates the formation of the folding portion 52 and the folding-back portion 53. Note that 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.

[0060] 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.

[0061] An electrolytic solution (not shown) may be injected into these internal spaces. The electrolytic solution may not be injected into these internal spaces. When the power storage module 1 does not include the electrolytic solution, the separator 40 may be a solid electrolyte.

[0062] 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. Regarding the same configuration as the power storage module according to Embodiment 1 among the power storage modules according to the comparative example, the description will not be repeated.

[0063] FIG. 3 is a cross-sectional view showing a part of the power storage module according to the comparative example. As shown in FIG. 3, the power storage module 9 according to the comparative example does not include the sealing sheet in Embodiment 1. The power storage module 9 according to the comparative example further includes a plurality of first sealing members 91, a plurality of spacers 92, a second sealing member 93, and an exterior body 94.

[0064] The plurality of first sealing materials 91 are arranged on both sides of each of the plurality of electrode plates 10 (current collector foils 110) in the second direction D2 of the end portion 11. The 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 the electrolytic solution into the internal space is secured. Furthermore, the plurality of first sealing materials 91 and the spacers 92 suppress the contact between the first current collector 112 of a certain current collector foil 110 and the second current collector 113 of another adjacent current collector foil 110. Here, in a laminated monopolar battery different from the comparative example, the plurality of positive electrode foils may have the same potential as each other, and the plurality of negative electrode foils may have the same potential as each other. However, in the power storage module 9 which is a bipolar battery, the plurality of current collector foils 110 always have different potentials from each other. Therefore, the plurality of first sealing materials 91 and the spacers 92 suppress the occurrence of a short circuit due to the 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 are buried in the second sealing material 93. Thereby, the 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.

[0065] 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 plurality of second sealing materials 93 are formed as separate members from each other. Note that it is difficult to manufacture all of these three types of plurality of members as an integral molded product. Further, it is also difficult to manufacture the first sealing material 91 and the pair of spacers 92 as an integral molded product, and even if such a molded product could be formed, it would be difficult to insert and arrange it between the current collecting foils 110. Further, if the first sealing material 91 and the pair of spacers 92 are formed as an integral molded product, the manufacturing cost may increase.

[0066] 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 of the current collecting foils 110 of the plurality of electrode plates 10 in the first direction D1. The sealing sheet 50 includes a plurality of side wall portions 51, a plurality of folded portions 52, and a folded-back portion 53. The plurality of side wall portions 51 are respectively arranged outside the current collecting foils 110 of the plurality of electrode plates 10 in the first direction D1. The plurality of folded portions 52 are folded from the respective plurality of side wall portions 51 toward between the plurality of electrode plates 10. The folded-back portion 53 connects the plurality of adjacent folded portions 52 to each other between the plurality of electrode plates 10. At least a part of the plurality of folded portions 52 is welded to the current collecting foils 110 of the corresponding plurality of electrode plates 10, respectively.

[0067] Thereby, the sealing sheet 50 can seal between the plurality of electrode plates 10 and can function as an exterior material for the plurality of electrode plates 10. Therefore, the number of members of the power storage module 1 can be reduced. Further, 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. Note that although the power storage module 1 is exemplified as a bipolar battery in the present embodiment, even if the power storage module 1 is a monopolar battery, the same effects can be achieved by having the above configuration.

[0068] Also, 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. Thereby, moisture permeation in the power storage module 1 can be suppressed without further providing another member different from the sealing sheet 50.

[0069] In addition, it is also preferable that the metal layer 502 is the outermost layer of the sealing sheet 50. Thereby, it is possible to suppress moisture from permeating through the sealing sheet 50, and the thickness of the sealing sheet 50 can be made relatively thin. By making the thickness of the sealing sheet 50 relatively thin, the power storage module 1 can be made more space-saving.

[0070] Furthermore, in the present embodiment, the resin layer 501 contains a polypropylene-based resin or a polyethylene-based resin. Thereby, the water absorption rate of the resin layer 501 can be lowered.

[0071] Also, 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 in the second direction D2 of the current collector foil 110. The second active material layer 130 is located on the other side in the second direction D2 of the current collector foil 110. 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 separators 40 are respectively disposed between the adjacent first active material layer 120 and second active material layer 130.

[0072] According to the above configuration, 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 which is 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 contact of the plurality of current collector foils 110 with each other. In order to suppress the contact between the current collector foils 110, 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 configuration in the present embodiment, by forming a plurality of folding portions 52 and folding-back portions 53 in one sealing sheet 50, the contact between the current collector foils 110 is suppressed. Furthermore, as described above, the sealing sheet 50 also functions as an exterior material. Therefore, the power storage module 1 in the present embodiment can significantly reduce the number of components compared to the bipolar battery in the comparative example when it is a bipolar battery.

[0073] Next, a method for manufacturing the power storage module 1 according to Embodiment 1 of the present disclosure will be described. FIG. 4 is a flowchart showing a method for manufacturing the power storage module according to Embodiment 1 of the present disclosure. As shown in FIGS. 1 to 4, the method for manufacturing the power storage module according to Embodiment 1 of the present disclosure includes a step S1 of covering the end portion 21 of the first terminal electrode 20 with the sealing sheet 50, and while laminating the plurality of electrode plates 10 on the first terminal electrode 20, covering the end portions 11 of the plurality of electrode plates 10 (current collector foils 110 thereof) with the sealing sheet 50 in step S2, and while laminating the second terminal electrode 30 on the electrode plate 10, covering the end portion 31 of the second terminal electrode 30 with the sealing sheet 50 in step S3, in this order.

[0074] First, step S1 will be described. FIG. 5 is a flowchart showing step S1 of the method for manufacturing the power storage module. FIGS. 6A to 6E are schematic cross-sectional views schematically showing the flow of step S1.

[0075] As shown in FIGS. 5 and 6A, in step S1, first, a first terminal electrode 20 is prepared (step S10). Then, a separator 40 is disposed on one surface (the first surface 22) of the first terminal electrode 20 (step S11).

[0076] Next, as shown in FIGS. 5, 6A, and 6B, a sealing sheet 50 is welded to a part of the other surface (the second surface 23) of the first terminal electrode 20 (step S12). Specifically, a first edge portion 54 of the sealing sheet 50 is welded 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 sandwiched while being heated from both sides in the second direction D2 by a pair of heaters 6. Thereby, the surface of the resin layer 501 of the first edge portion 54 melts and is thermally welded to the first terminal electrode 20.

[0077] Next, as shown in FIGS. 5, 6B, and 6C, the sealing sheet 50 is folded from the other surface (the second surface 23) side of the first terminal electrode 20 so that the sealing sheet 50 covers the end portion 21 of the first terminal electrode 20 and a part of one surface (the first surface 22) of the first terminal electrode 20 (step S13). Thereby, a side wall portion 51 is formed on the outer side of the first terminal electrode 20 in the first direction D1. Further, a folded portion 52 is formed on the first surface 22 side of the first terminal electrode 20.

[0078] Next, as shown in FIGS. 5, 6C, and 6D, a sealing sheet 50 is welded to a part of one surface (the first surface 22) of the first terminal electrode 20 (step S14). Specifically, the folded sealing sheet 50 (the folded portion 52) is welded 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 portion 52, together with the first edge portion 54, are sandwiched while being heated from both sides in the second direction D2 by a pair of heaters 6. Thereby, the surface of the resin layer 501 of the folded portion 52 melts and is thermally welded to the first terminal electrode 20.

[0079] At the end of step S1, as shown in FIGS. 5, 6D, and 6E, on one side (the first surface 22) of the first terminal electrode 20, the sealing sheet 50 is folded back (step S15). As a result, the sealing sheet 50 extends outward toward the outside of the first terminal electrode 20 in the first direction D1. Specifically, the vicinity of the inside of the portion of the folded sealing sheet 50 that is welded to the first surface 22 of the first terminal electrode 20 is folded back.

[0080] Thus, in this embodiment, step S1 includes steps S10 to S15 in this order. However, the order of steps S10 to S15 is not limited to the above.

[0081] Next, step S2 will be described. In step S2, a series of steps are repeated. Therefore, in the following, some of the steps included in step S2 will be described.

[0082] FIG. 7 is a flowchart showing a part of step S2 of the method for manufacturing a power storage module. FIGS. 8A to 8F are schematic cross-sectional views schematically showing a part of the flow of step S2.

[0083] The step of covering the end portion 11 of the first electrode plate 10A (the current collector foil 110 thereof) with the sealing sheet 50 as the electrode plate 10 will be described. First, as shown in FIGS. 7 and 8A, the first electrode plate 10A is prepared (step S20A). Then, the first separator 40A is disposed on one surface (the first surface 12) of the first electrode plate 10A (step S21A).

[0084] Next, as shown in FIGS. 7, 8A, and 8B, a folded sealing sheet 50 is welded to a part of the other surface (the second surface 13) of the first electrode plate 10A (step S22A). Specifically, a part of the folded sealing sheet 50 is welded to the second surface 13 of the end portion 11 of the first electrode plate 10A (the current collecting foil 110). The end portion 11 of the first electrode plate 10A (the current collecting foil 110) and a part of the folded sealing sheet 50 are sandwiched while being heated from both sides in the second direction D2 by a pair of heaters 6. Thereby, the surface of the resin layer 501 of the folded sealing sheet 50 melts and is heat-welded to the first electrode plate 10A.

[0085] The above-mentioned folded sealing sheet 50 is a sealing sheet 50 having a folded portion 52 welded to the first surface 12 of another electrode plate 10 different from the first electrode plate 10A. When the first electrode plate 10A is an electrode plate 10 adjacent to the first terminal electrode 20, the above-mentioned folded sealing sheet 50 may be a sealing sheet 50 having a folded portion 52 welded to the first surface 22 of the first terminal electrode 20.

[0086] Next, as shown in FIGS. 7, 8B, and 8C, the sealing sheet 50 is folded from the other surface (the second surface 13) side of the first electrode plate 10A so as to cover the end portion 11 of the first electrode plate 10A (the current collecting foil 110) and a part of the one surface (the first surface 12) of the first electrode plate 10A (step S23A). Thereby, a folded portion 52 is formed on the second surface 13 side of the first electrode plate 10A. And a side wall portion 51 is formed outside the first electrode plate 10A in the first direction D1. Furthermore, a folded portion 52 is also formed on the first surface 12 side of the first electrode plate 10A.

[0087] Next, as shown in FIGS. 7, 8C, and 8D, a sealing sheet 50 is welded to a part of one surface (the first surface 12) of the first electrode plate 10A (step S24A). Specifically, the folded sealing sheet 50 (the folded portion 52) is welded to the first surface 12 of the end portion 11 of the first electrode plate 10A (the current collector foil 110). The end portion 11 of the first electrode plate 10A (the current collector foil 110) and the folded portion 52 on the first surface 12 are sandwiched while being heated from both sides in the second direction D2 by a pair of heaters 6 together with the folded portion 52 on the second surface 13. Thereby, the surface of the resin layer 501 of the folded portion 52 on the first surface 12 melts and thermally welds to the first electrode plate 10A.

[0088] Next, as shown in FIGS. 7, 8D, and 8E, the first electrode plate 10A is disposed on the separator 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 separator 40 of the other electrode plate 10. At the same time, the folded portion 52 disposed on the second surface 13 of the first electrode plate 10A is disposed on the folded portion 52 disposed on the first surface 12 of the other electrode plate 10. Thereby, a folded-back portion 53 that connects these folded portions 52 to each other is formed between the first electrode plate 10A and the other electrode plate 10. Even when the first electrode plate 10A is an electrode plate 10 adjacent to the first terminal electrode 20, the folded-back portion 53 is formed between the first electrode plate 10A and the first terminal electrode 20 in the same manner as described above.

[0089] Next, as shown in FIGS. 7, 8E, and 8F, the sealing sheet 50 is folded back on the side of one surface (the first surface 12) of the first electrode plate 10A (step S26A). Thereby, the sealing sheet 50 extends outward of 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 welded to the first surface 12 of the first electrode plate 10A is folded back.

[0090] As described above, in the present embodiment, step S2 includes steps S20A to S26A in this order. In steps S20A to S26A, while laminating the first electrode plate 10A on the other electrode plate 10 via the separator 40, the end portion 11 of the first electrode plate 10A (the current collector foil 110 thereof) is covered with a sealing sheet. However, the order of steps S20A to S26A is not limited to the above.

[0091] In step S2, the above-described steps S20A to S26A are repeated the number of times equal to the number of electrode plates 10. FIGS. 9A to 9F are schematic cross-sectional views schematically showing a continuation of a part of the flow of step S2 shown in FIGS. 8A to 8F. For example, as shown in FIGS. 7 and 9A to 9F, in steps S20B to S26B, while laminating the second electrode plate 10B on the first electrode plate 10A via the first separator 40A, the end portion 11 of the second electrode plate 10B (the current collector foil 110 thereof) is covered with a sealing sheet 50. Steps S20B to S26B can be implemented by replacing the other electrode plate 10 and the first electrode plate 10A and the other separator 40 and the first separator 40A in steps S20A to S26A with the first electrode plate 10A and the second electrode plate 10B and the first separator 40A and the second separator 40B, respectively.

[0092] As shown in FIGS. 7, 8A to 8F, and 9A to 9F, the method for manufacturing the power storage module 1 according to the embodiment of the present disclosure includes disposing the first separator 40A on the active material layer located on one side (the first surface 12) of the first electrode plate 10A including the current collector foil 110 and at least one active material layer applied to the current collector foil (step S21A); folding the sealing sheet 50 from the other side (the second surface 13) side 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); welding 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); folding back the sealing sheet 50 on the one side (the first surface 12) side of the current collector foil 110 of the first electrode plate 10A (step S26A); welding the folded 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 the 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 applied to the current collector foil (step S22B); folding the sealing sheet 50 from the other side (the second surface 13) side of the current collector foil 110 of the second electrode plate 10B so that the folded 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 separator 40A (step S25B).

[0093] 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 material for the first electrode plate 10A and the second electrode plate 10B. Therefore, the number of members of the power storage module 1 can be reduced. As a result, the structure of the power storage module 1 can be simplified. Further, according to the above configuration, since the relatively thin 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, 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.

[0094] Also, the step of disposing the active material layer of the second electrode plate 10B on the first separator 40A (step S25B) is performed after welding the sealing sheet 50 to a part of one surface (the first surface 12) of the current collector foil 110 of the first electrode plate 10A (step S24A) and after welding the folded-back sealing sheet 50 to a part of the other surface (the second surface 13) of the current collector foil 110 of the second electrode plate 10B (step S22B).

[0095] Thereby, in the process of laminating the first electrode plate 10A, the separator 40, and the second electrode plate 10B on each other, the sealing sheet 50 can be welded. As a result, the number of manufacturing steps of the power storage module 1 can be reduced.

[0096] Finally, step S3 will be described. FIG. 10 is a flowchart showing step S3 of the method for manufacturing a power storage module. FIGS. 11A to 11E are schematic cross-sectional views schematically showing the flow of step S3.

[0097] As shown in FIGS. 10 and 11A, first, a second terminal electrode 30 is prepared (step S30). Next, as shown in FIGS. 10, 11A, and 11B, a folded-back sealing sheet 50 is welded to a part of the other surface (the second surface 33) of the second terminal electrode 30 (step S31). Specifically, a part of the folded-back sealing sheet 50 is welded 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 sandwiched while being heated from both sides in the second direction D2 by a pair of heaters 6. Thereby, the surface of the resin layer 501 of the folded-back sealing sheet 50 melts and is thermally welded to the second terminal electrode 30. The above-mentioned folded-back sealing sheet 50 is the sealing sheet 50 in which a folded portion 52 is formed by being welded to the first surface 12 of the electrode plate 10 adjacent to the second terminal electrode 30.

[0098] Next, as shown in FIGS. 10, 11B, and 11C, the sealing sheet 50 is folded from the other surface (second surface 33) side 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 portion 52 is formed on the second surface 13 side of the second terminal electrode 30. And a side wall portion 51 is formed outside the second terminal electrode 30 in the first direction D1. 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.

[0099] Next, as shown in FIGS. 10, 11C, and 11D, the sealing sheet 50 is welded to a part of one surface (first surface 32) of the second terminal electrode 30 (step S33). Specifically, the second edge portion 55 of the sealing sheet 50 is welded to the first surface 32 of the end portion 31 of the second terminal electrode 30. The end portion 31 of the second terminal electrode 30 and the second edge portion 55 on the first surface 32 are sandwiched while being heated from both sides in the second direction D2 by a pair of heaters 6 together with the folded portion 52 on the second surface 33. 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 welded to the second terminal electrode 30.

[0100] Finally, as shown in FIGS. 10, 11D, and 11E, the second terminal electrode 30 is disposed on the separator 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 separator 40 of the electrode plate 10 adjacent to the second terminal electrode 30. At the same time, 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 that connects these folded portions 52 to each other is formed between the second terminal electrode 30 and the electrode plate 10.

[0101] Thus, in the present embodiment, step S3 includes steps S30 to S34 in this order. However, the order of steps S30 to S34 is not limited to the above.

[0102] Through the above-described step S1, step S2, and step S3, the power storage module according to Embodiment 1 of the present disclosure can be manufactured.

[0103] (Embodiment 2) Next, a power storage module according to Embodiment 2 of the present disclosure will be described. The configuration of the plurality of folded portions of the power storage module according to Embodiment 2 is different from that of the power storage module according to Embodiment 1. Note that descriptions of the same configurations and effects as those of the power storage module according to Embodiment 1 will not be repeated.

[0104] FIG. 12 is a cross-sectional view showing a part of the power storage module according to Embodiment 2 of the present disclosure. In FIG. 12, the power storage module is illustrated in the same cross-sectional view as FIG. 2 in Embodiment 1.

[0105] As shown in FIG. 12, 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 portion 53a. Thereby, the stress of the folded portion 53 of the sealing sheet 50 can be relaxed.

[0106] The groove portion 56a may be formed in any of the folded portions 53a. One or more groove portions 56a may be respectively formed in one or more folded portions 53a located between the electrode plates 10. The groove portion 56a may be formed in the folded 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 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 portions 53a.

[0107] The groove portion 56a may extend in a direction orthogonal to the plane of the paper in FIG. 12 (that is, a 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 be exposed in the groove portion 56a. Through the groove portion 56a, the resin layer 501 may be divided into a plurality of portions.

[0108] (Embodiment 3) Next, a power storage module according to Embodiment 3 of the present disclosure will be described. The power storage module according to Embodiment 3 is different from the power storage module according to Embodiment 1 in the configuration of the sealing sheet. Regarding the same configurations and effects as those of the power storage module according to Embodiment 1, the description will not be repeated.

[0109] FIG. 13 is a cross-sectional view showing a part of the power storage module according to Embodiment 3 of the present disclosure. In FIG. 13, the power storage module is illustrated in the same cross-sectional view as FIG. 2 in Embodiment 1.

[0110] As shown in FIG. 13, in the power storage module 1b according to Embodiment 2 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.

[0111] Between the plurality of electrode plates 10, at least a part of the outer resin layers 503b of the plurality of folding portions 52b (a pair of folding portions 52b) are welded to each other. Thereby, the shape of the sealing sheet 50b can be maintained more firmly.

[0112] In the manufacturing method of the power storage module 1b according to the present embodiment, after covering each end portion 21, 11, 31 with the sealing sheet 50b in the same manner as steps S1 to S3 in the manufacturing method of the power storage module according to Embodiment 1, the plurality of pairs of folding portions 52b are heated. Thereby, the outer resin layers 503b of the respective pairs of folding portions 52b are heat-welded to each other. At this time, the pair of folding portions 52b can be heated from the side opposite to the folded-back portion 53 side.

[0113] In the description of the above-described embodiments, combinable configurations may be combined with each other.

[0114] The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Description of Reference Numerals

[0115] 1, 1a, 1b Battery module, 10 Electrode plate, 10A First electrode plate, 10B Second electrode plate, 11 End portion, 12 First surface, 13 Second surface, 110 Current collector foil, 112 First current collector, 113 Second current collector, 120 First active material layer, 130 Second active material layer, 20 First terminal electrode, 21 End portion, 22 First surface, 23 Second surface, 30 Second terminal electrode, 31 End portion, 32 First surface, 33 Second surface, 40 Separator, 40A First separator, 40B Second separator, 50, 50b Sealing sheet, 51 Side wall portion, 52, 52b Folded portion, 53, 53a Turned-back portion, 54 First edge, 55 Second edge, 56a Groove portion, 501, 501b Resin layer, 502, 502b Metal layer, 503b Outer resin layer, 6 Heater.

Claims

1. 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 surface direction of each of the plurality of electrode plates extends along a first direction, the plurality of electrode plates are arranged side by side with each other in a second direction orthogonal to the first direction, the plurality of separators are respectively arranged between the active material layers of the plurality of electrode plates adjacent to each other, the sealing sheet covers the ends of the current collector foils of the plurality of electrode plates in the first direction, the sealing sheet, a plurality of side wall portions respectively arranged outside the current collector foils of the plurality of electrode plates in the first direction, a plurality of folding portions folded from each of the plurality of side wall portions toward between the plurality of electrode plates, and a folding-back portion connecting the plurality of folding portions adjacent to each other between the plurality of electrode plates, at least a part of the plurality of folding portions is welded to the current collector foils of the corresponding plurality of electrode plates, a power storage module.

2. 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, the power storage module according to claim 1.

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

4. A groove portion is formed in the resin layer of the folding-back portion, the power storage module according to claim 2 or claim 3.

5. 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, the power storage module according to claim 2 or claim 3.

6. Between the plurality of electrode plates, at least a part of the outer resin layers of the plurality of folding portions are welded to each other, the power storage module according to claim 5.

7. 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 power storage module according to claim 1, wherein 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, which is a power storage module composed of bipolar batteries.

9. Disposing a separator on the active material layer located on one side of the first electrode plate including a current collector foil and at least one active material layer coated on the current collector foil; Folding the sealing sheet from the other side of the current collector foil of the first electrode plate so that the sealing sheet covers an end of the current collector foil of the first electrode plate and a part of the one side of the current collector foil of the first electrode plate; Welding the sealing sheet to a part of the one side of the current collector foil of the first electrode plate; Folding back the sealing sheet on the one side of the current collector foil of the first electrode plate; Welding the folded sealing sheet to a part of the other side of the current collector foil of the second electrode plate, which is opposite to the one side of the current collector foil of the second electrode plate including a current collector foil and at least one active material layer coated on the current collector foil; Folding the sealing sheet from the other side of the current collector foil of the second electrode plate so that the folded sealing sheet covers an end of the current collector foil of the second electrode plate and a part of the one side of the current collector foil of the second electrode plate; A method for manufacturing a power storage module, comprising disposing the active material layer of the second electrode plate on the separator.

10. The step of disposing the active material layer of the second electrode plate on the separator is performed after welding the sealing sheet to a part of the one side of the current collector foil of the first electrode plate and after welding the folded sealing sheet to a part of the other side of the current collector foil of the second electrode plate. The method for manufacturing a power storage module according to claim 9.

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