JP2019212422A - Power storage module - Google Patents

Abstract

To provide a power storage module capable of suppressing pressure rise in an internal space.SOLUTION: A power storage module 4 comprises: an electrode laminate 11 in which a plurality of bipolar electrodes 14 are laminated via a separator 13; and a sealing body 12 which seals a portion between the bipolar electrodes 14 that are adjacent to each other in a lamination direction D in the electrode laminate 11. The sealing body 12 has: primary sealing bodies 21A, 21B provided on an outer edge 15c of each of the bipolar electrodes 14; and a secondary sealing body 22 provided around the primary sealing bodies 21A, 21B. The primary sealing body 21B has: a first resin layer 23 bonded to the outer edge 15c; and a second resin layer 24 laminated on the first resin layer 23 in the lamination direction D. When viewed in the lamination direction D, the first resin layer 23 has an exposed region 23c which is exposed from the second resin layer 24, and in which an outer edge 13a of the separator 13 is located. In the lamination direction D, a thickness t1 of the first resin layer 23 is thinner than a thickness t2 of the second resin layer 24.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power storage module.

  As a conventional power storage module, a so-called bipolar power storage module including a bipolar electrode in which a positive electrode is formed on one surface of an electrode plate and a negative electrode is formed on the other surface is known (see Patent Document 1). Such a power storage module includes an electrode laminate formed by laminating a plurality of bipolar electrodes via a separator. A sealing body that seals between the bipolar electrodes adjacent in the stacking direction is provided on the side surface of the electrode stack. An electrolytic solution is accommodated in the internal space formed by the bipolar electrode and the sealing body adjacent in the stacking direction.

JP 2011-204386 A

  In the above-described power storage module, the pressure in the internal space may increase due to the generation of gas. When the pressure in the internal space rises, there is a risk that problems such as leakage of electrolyte from the joint between the sealing body and the bipolar electrode may occur.

  Then, an object of this invention is to provide the electrical storage module which can suppress the raise of the pressure of internal space.

  An electricity storage module according to the present invention includes an electrode stack including a plurality of bipolar electrodes stacked via separators, and a sealing body that seals between bipolar electrodes adjacent in the stacking direction in the electrode stack. The stationary body includes a primary sealing body provided at an outer edge portion of the bipolar electrode, and a secondary sealing body provided around the primary sealing body, and the primary sealing body is an outer edge of the bipolar electrode. A first resin layer bonded to the portion and a second resin layer laminated in the lamination direction on the first resin layer, and the first resin layer is formed from the second resin layer as viewed from the lamination direction. It has an exposed region where the outer edge portion of the separator is exposed, and the thickness of the first resin layer is smaller than the thickness of the second resin layer in the stacking direction.

  In this power storage module, between the bipolar electrodes adjacent in the stacking direction in the electrode stack is sealed with a seal. Thus, an internal space is formed by the bipolar electrode and the sealing body that are adjacent in the stacking direction. The sealing body is provided at the outer edge portion of the bipolar electrode and has a primary sealing body. The primary sealing body has a first resin layer and a second resin layer, and the first resin layer includes an exposed region in which an outer edge portion of the separator is disposed. In the laminating direction, the thickness of the first resin layer is smaller than the thickness of the second resin layer, so that the internal space is smaller than when the thickness of the first resin layer is equal to or greater than the thickness of the second resin layer. Can be spread. Thereby, the rise in the pressure of the internal space due to the generation of gas can be suppressed.

  In the electricity storage module of the present invention, the outer edge of the first resin layer may coincide with the outer edge of the second resin layer as viewed from the stacking direction. In this case, since the position of the end surface on the outer edge portion side of the primary sealing body is aligned, it is difficult for a gap to be generated between the end surface on the outer edge portion side of the primary sealing body and the inner surface of the secondary sealing body. Thereby, the joint strength of a primary sealing body and a secondary sealing body can be raised.

  In the electricity storage module of the present invention, the first resin layer and the second resin layer may be configured by a single folded resin layer. In this case, it is not necessary to prepare separate resin layers for the first resin layer and the second resin layer.

  In the electricity storage module of the present invention, the joint surface of the electrode plate constituting the bipolar electrode with the first resin layer is a rough plating surface, and the thickness of the first resin layer is a protrusion on the rough plating surface. It may be larger than the maximum height. In this case, since the protrusion is suppressed from being exposed from the first resin layer, the insulation between the adjacent bipolar electrodes can be maintained.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage module which can suppress the raise of the pressure of internal space can be provided.

It is a schematic sectional drawing which shows one Embodiment of an electrical storage apparatus. It is a schematic sectional drawing which shows the internal structure of the electrical storage module shown by FIG. It is a principal part expansion schematic diagram which shows the structure of a sealing body. It is a schematic sectional drawing which shows the joining interface of an electrode plate and a primary sealing body. FIG. 5A is a schematic diagram illustrating a primary sealing body according to a comparative example, and FIG. 5B is a schematic diagram illustrating a primary sealing body according to the embodiment. It is a principal part expansion schematic diagram which shows the structure of the sealing body of the electrical storage module which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or equivalent part, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a power storage device. The power storage device 1 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 includes a module stack 2 including a plurality of stacked power storage modules 4 and a restraining member 3 that applies a restraining load to the module stack 2 in the stacking direction.

  The module laminate 2 includes a plurality (here, three) of power storage modules 4 and a plurality (here, four) of conductive plates 5. The power storage module 4 is a bipolar battery, and has a rectangular shape when viewed from the stacking direction. The power storage module 4 is, for example, a secondary battery such as a nickel hydride secondary battery or a lithium ion secondary battery, or an electric double layer capacitor. In the following description, a nickel metal hydride secondary battery is illustrated.

  The power storage modules 4 adjacent to each other in the stacking direction are electrically connected via the conductive plate 5. The conductive plates 5 are respectively disposed between the power storage modules 4 adjacent to each other in the stacking direction and the outside of the power storage module 4 positioned at the stacking end. A positive electrode terminal 6 is connected to one conductive plate 5 disposed outside the power storage module 4 located at the end of the stack. A negative electrode terminal 7 is connected to the other conductive plate 5 disposed outside the power storage module 4 located at the stacking end. The positive electrode terminal 6 and the negative electrode terminal 7 are drawn out, for example, from the edge of the conductive plate 5 in a direction crossing the stacking direction. The power storage device 1 is charged and discharged by the positive electrode terminal 6 and the negative electrode terminal 7.

  Inside the conductive plate 5, a plurality of flow paths 5 a for circulating a refrigerant such as air are provided. The flow path 5a extends, for example, along a direction intersecting (orthogonal) with each other in the stacking direction and the drawing direction of the positive electrode terminal 6 and the negative electrode terminal 7. In addition to the function as a connection member for electrically connecting the power storage modules 4 to each other, the conductive plate 5 serves as a heat dissipation plate that dissipates heat generated in the power storage module 4 by circulating a refrigerant through these flow paths 5a. It has both functions. In the example of FIG. 1, the area of the conductive plate 5 viewed from the stacking direction is smaller than the area of the power storage module 4, but from the viewpoint of improving heat dissipation, the area of the conductive plate 5 is the area of the power storage module 4. It may be the same as or larger than the area of the power storage module 4.

  The restraining member 3 includes a pair of end plates 8 that sandwich the module laminate 2 in the stacking direction, and fastening bolts 9 and nuts 10 that fasten the end plates 8 together. The end plate 8 is a rectangular metal plate having an area that is slightly larger than the areas of the power storage module 4 and the conductive plate 5 as viewed from the stacking direction. On the inner side surface of the end plate 8 (surface on the module laminate 2 side), a film F having electrical insulation is provided. The film F insulates the end plate 8 from the conductive plate 5.

  An insertion hole 8 a is provided at the edge of the end plate 8 at a position outside the module laminate 2. The fastening bolt 9 is passed from the insertion hole 8 a of one end plate 8 toward the insertion hole 8 a of the other end plate 8, and at the tip of the fastening bolt 9 protruding from the insertion hole 8 a of the other end plate 8. The nut 10 is screwed together. As a result, the power storage module 4 and the conductive plate 5 are sandwiched between the end plates 8 and unitized as the module stacked body 2, and a restraining load is applied to the module stacked body 2 in the stacking direction.

  Next, the configuration of the power storage module 4 will be described in detail. FIG. 2 is a schematic cross-sectional view showing an internal configuration of the power storage module shown in FIG. As shown in FIG. 2, the power storage module 4 includes an electrode stack 11 and a sealing body 12 that seals the electrode stack 11. The electrode laminate 11 has a plurality of bipolar electrodes 14 laminated via separators 13. Here, the stacking direction D of the electrode stack 11 coincides with the stacking direction of the module stack 2. The electrode stack 11 has a side surface 11a extending in the stacking direction D.

  The bipolar electrode 14 includes an electrode plate 15, a positive electrode 16 provided on one surface 15 a of the electrode plate 15, and a negative electrode 17 provided on the other surface 15 b of the electrode plate 15. The positive electrode 16 is a positive electrode active material layer formed by coating a positive electrode active material. The negative electrode 17 is a negative electrode active material layer formed by coating a negative electrode active material. In the electrode stack 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of one bipolar electrode 14 adjacent in the stacking direction D across the separator 13. In the electrode stack 11, the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of the other bipolar electrode 14 adjacent in the stacking direction D with the separator 13 interposed therebetween.

  In the electrode stack 11, a negative electrode termination electrode 18 is disposed at one end in the stacking direction D. A positive electrode termination electrode 19 is disposed at the other end in the stacking direction D. The negative electrode termination electrode 18 includes an electrode plate 15 and a negative electrode 17 provided on the other surface 15 b of the electrode plate 15. The negative electrode 17 of the negative electrode termination electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D through the separator 13. One conductive plate 5 adjacent to the power storage module 4 is in contact with one surface 15 a of the electrode plate 15 of the negative electrode termination electrode 18. The positive electrode termination electrode 19 includes an electrode plate 15 and a positive electrode 16 provided on one surface 15 a of the electrode plate 15. The other conductive plate 5 adjacent to the power storage module 4 is in contact with the other surface 15 b of the electrode plate 15 of the positive electrode termination electrode 19. The positive electrode 16 of the positive electrode termination electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D through the separator 13.

  The conductive plate 5 (see FIG. 1) is in contact with one surface 15a of the electrode plate 15 of the negative terminal electrode 18. Further, the other conductive plate 5 (see FIG. 1) adjacent to the power storage module 4 is in contact with the other surface 15 b of the electrode plate 15 of the positive electrode termination electrode 19. The restraining load from the restraining member 3 (see FIG. 1) is applied to the electrode laminate 11 from the negative terminal electrode 18 and the positive terminal electrode 19 via the conductive plate 5. That is, the conductive plate 5 is also a restraining member that applies a restraining load to the electrode laminate 11 along the stacking direction D.

  The electrode plate 15 is made of, for example, a metal foil made of nickel or a nickel-plated steel plate, and has a rectangular shape. The outer edge portion 15c of the electrode plate 15 is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. An example of the positive electrode active material constituting the positive electrode 16 is nickel hydroxide. As a negative electrode active material which comprises the negative electrode 17, a hydrogen storage alloy is mentioned, for example. In the present embodiment, the formation region of the negative electrode 17 on the other surface 15 b of the electrode plate 15 is slightly larger than the formation region of the positive electrode 16 on the one surface 15 a of the electrode plate 15.

  The separator 13 is formed in a sheet shape, for example. Examples of the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose, and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound.

  FIG. 3 is an enlarged schematic view of the main part showing the configuration of the sealing body. The sealing body 12 shown in FIG.2 and FIG.3 is formed in the rectangular cylinder shape, for example with insulating resin. The sealing body 12 is configured to hold the outer edge portion 15c of the electrode plate 15 on the side surface 11a of the electrode stacked body 11 extending in the stacking direction D and surround the side surface 11a. The sealing body 12 seals between the bipolar electrodes 14 adjacent in the stacking direction D in the electrode stack 11.

  The sealing body 12 has primary sealing bodies 21A and 21B and a secondary sealing body 22 provided around the primary sealing bodies 21A and 21B. 21 A of primary sealing bodies are provided in the outer edge part 15c by the side of the one surface 15a of the electrode plate 15 which comprises the negative electrode termination electrode 18, and the outer edge part 15c by the side of the other surface 15b of the electrode plate 15 which comprises the positive electrode termination electrode 19. ing. The primary sealing body 21 </ b> B is provided on the outer edge portion 15 c on the one surface 15 a side of the electrode plate 15 that constitutes each bipolar electrode 14 and the positive electrode termination electrode 19. The secondary sealing body 22 is provided so as to surround the group of the primary sealing bodies 21A and 21B from the outside.

  The primary sealing bodies 21A and 21B are formed by, for example, resin injection molding. The primary sealing bodies 21A and 21B are rectangular frame films having a predetermined thickness (length in the stacking direction D). The primary sealing bodies 21 </ b> A and 21 </ b> B are continuously provided over the entire circumference (all sides) of the electrode plate 15 at the outer edge portion 15 c (uncoated region) on the one surface 15 a side of the electrode plate 15. The primary sealing bodies 21A and 21B or the primary sealing bodies 21B that are adjacent along the stacking direction D are separated from each other. 2 and 3, the primary sealing body 21B provided on one electrode plate 15 and the other surface 15b of one electrode plate 15 adjacent in the stacking direction D are separated from each other but are in contact with each other. May be.

  The primary sealing bodies 21A and 21B have an inner edge portion 21a and an outer edge portion 21b. The inner edge portion 21 a overlaps the electrode plate 15 when viewed from the stacking direction D. The outer edge portion 21 b protrudes outside the electrode plate 15 when viewed from the stacking direction D. At least a part of the inner edge portion 21 a is airtightly joined to the outer edge portion 15 c of the electrode plate 15. The end surfaces of the primary sealing bodies 21 </ b> A and 21 </ b> B on the outer edge portion 21 b side are airtightly joined to the inner surface 22 a of the secondary sealing body 22.

  The primary sealing body 21A has a single layer structure. The primary sealing body 21 </ b> B has a laminated structure in which the first resin layer 23 and the second resin layer 24 are laminated in the lamination direction D. The first resin layer 23 and the second resin layer 24 are rectangular frame films having the same outer edge size and different inner edge sizes. When viewed from the stacking direction D, the outer edge 23 a of the first resin layer 23 coincides with the outer edge 24 a of the second resin layer 24. When viewed from the stacking direction D, the inner edge 23 b of the first resin layer 23 is located inside the inner edge 24 b of the second resin layer 24. As a result, the primary sealing body 21 </ b> B is formed with a step whose height matches the thickness t <b> 2 (the length in the stacking direction D) of the second resin layer 24.

  In the present embodiment, the first resin layer 23 and the second resin layer 24 are separate members. The first resin layer 23 is bonded (welded) to the outer edge portion 15c on the one surface 15a side of the electrode plate 15 by, for example, heat or ultrasonic waves. The second resin layer 24 is laminated on the first resin layer 23. The second resin layer 24 faces the one surface 15 a of the electrode plate 15 in the stacking direction D with the first resin layer 23 interposed therebetween. The second resin layer 24 is bonded (welded) to the first resin layer 23 by heat, for example. For example, the second resin layer 24 may be partially welded to the first resin layer 23 at a plurality of points arranged along the outer edge portion 15c, or may be welded to the first resin layer 23 entirely. Also good.

  The first resin layer 23 includes an exposed region 23 c exposed from the second resin layer 24 and a covering region 23 d covered with the second resin layer 24 when viewed from the stacking direction D. The outer edge portion 13a of the separator 13 is disposed (placed) in the exposed region 23c. The adjacent electrode plates 15 are kept insulated from each other by the separator 13 and the primary sealing bodies 21A and 21B.

  The covering region 23d is disposed outside the exposed region 23c. When viewed from the stacking direction D, the outer edge of the separator 13 is located between the inner edge 23 b of the first resin layer 23 and the inner edge 24 b of the second resin layer 24. When viewed from the stacking direction D, the inner edge of the covering region 23 d (the inner edge 24 b of the second resin layer 24) is located inside the outer edge of the electrode plate 15. The entire exposed region 23c and a part of the covering region 23d and the second resin layer 24 constitute an inner edge portion 21a. The remaining portion of the covering region 23d and the second resin layer 24 constitutes an outer edge portion 21b.

  In the stacking direction D, the thickness t1 of the first resin layer 23 (length in the stacking direction D) is smaller than the thickness t2 of the second resin layer 24 (length in the stacking direction D). For example, the thickness t1 can be made smaller than the thickness t2 by joining the first resin layer 23 to the outer edge portion 15c by hot pressing and compressing (crushing) the first resin layer 23. In this case, it is not necessary to prepare films having different thicknesses for the first resin layer 23 and the second resin layer 24, and films having the same thickness can be prepared. The size of the thickness t1 can be appropriately adjusted by the amount of compression (crushing amount) of the film by hot pressing.

  The thickness t2 is set to be larger than the thickness of the separator 13 (the length in the stacking direction D). Thereby, for example, even when the outer edge portion of the electrode laminate 11 is pressed in the lamination direction D by the mold during the injection molding of the secondary sealing body 22, the separator 13 does not interfere with the electrode plate 15, The deformation of the electrode plate 15 due to the interference of the separator 13 can be suppressed. The thickness t2 is, for example, 150 μm. The thickness t1 is, for example, not less than 70 μm and not more than 200 μm because of easy compression by hot pressing.

  FIG. 4 is a schematic cross-sectional view showing the bonding interface between the electrode plate constituting the bipolar electrode and the primary sealing body. As shown in FIG. 4, one surface 15a of the electrode plate 15 constituting the bipolar electrode 14 is roughened. The entire surface 15a is a roughened plated surface that is roughened by forming a plurality of protrusions 15p by electrolytic plating, for example. The one surface 15a is a joint surface with the first resin layer 23 of the primary sealing body 21B. Thus, when the joint surface with the 1st resin layer 23 in the electrode plate 15 which comprises the bipolar electrode 14 is a roughening plating surface, in a joining interface of the electrode plate 15 and the primary sealing body 21B, it is a molten state. The primary sealing body 21B enters the recess formed by the roughening, and the anchor effect is exhibited. Thereby, in the bipolar electrode 14, the coupling force and liquid tightness of the electrode plate 15 and the primary sealing body 21B can be improved.

  In the present embodiment, the entire surface of the one surface 15a is roughened, but only the outer edge portion 15c of the one surface 15a may be roughened. In addition to the one surface 15a, the other surface 15b and the end surface of the electrode plate 15 may be roughened. The protrusion 15p has, for example, a shape that tapers from the proximal end side toward the distal end side. In this case, the cross-sectional shape between the adjacent protrusions 15p is an undercut shape, and an anchor effect is likely to occur. FIG. 4 is a schematic diagram, and the shape and density of the protrusions 15p are not particularly limited.

  In the present embodiment, the one surface 15 a of the electrode plate 15 in the negative electrode termination electrode 18 and the positive electrode termination electrode 19 is also roughened. Thereby, in the negative electrode termination electrode 18, the coupling force between the electrode plate 15 and the primary sealing body 21A can be improved, and in the positive electrode termination electrode 19, the coupling force between the electrode plate 15 and the primary sealing body 21B is improved. Can be made.

  The thickness t1 of the first resin layer 23 shown in FIG. 3 is set to be larger than the maximum height of the protrusion 15p shown in FIG. The maximum height of the protrusion 15p is the maximum value of the height h from the one surface 15a of the top of the protrusion 15p. The maximum height of the protrusion 15p is, for example, less than 10 μm. In this case, if the thickness t1 is set to 10 μm or more, the protrusion 15p is suppressed from being exposed from the first resin layer 23, so that the insulating state between the adjacent electrode plates 15 can be maintained.

  The secondary sealing body 22 is provided outside the electrode stack 11 and the primary sealing bodies 21 </ b> A and 21 </ b> B, and constitutes the outer wall (housing) of the power storage module 4. The secondary sealing body 22 is formed by, for example, resin injection molding, and extends along the stacking direction D over the entire length of the electrode stack 11. The secondary sealing body 22 has a cylindrical shape (annular shape) extending with the stacking direction D as the axial direction. The secondary sealing body 22 is welded (joined) to the end face on the outer edge portion 21b side of the primary sealing bodies 21A and 21B, for example, by heat during injection molding.

  The secondary sealing body 22, together with the primary sealing bodies 21 </ b> A and 21 </ b> B, is connected between the pair of bipolar electrodes 14 adjacent to each other along the stacking direction D and between the negative electrode termination electrode 18 and the bipolar electrode adjacent to each other along the stacking direction D. 14 and between the positive electrode termination electrode 19 and the bipolar electrode 14 adjacent to each other along the stacking direction D are sealed. As a result, airtightly partitioned internal spaces V are formed between the pair of bipolar electrodes 14, between the negative electrode termination electrode 18 and the bipolar electrode 14, and between the positive electrode termination electrode 19 and the bipolar electrode 14, respectively. Has been. Each internal space V includes a space between a pair of outer edge portions 21b adjacent in the stacking direction D. In each internal space V, an electrolytic solution (not shown) made of an alkaline aqueous solution such as an aqueous potassium hydroxide solution is accommodated. The electrolytic solution is impregnated in the separator 13, the positive electrode 16, and the negative electrode 17.

  The primary sealing bodies 21A and 21B and the secondary sealing body 22 are, for example, insulating resins, and can be made of polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), or the like. .

  FIG. 5A is a schematic diagram illustrating a primary sealing body according to a comparative example, and FIG. 5B is a schematic diagram illustrating a primary sealing body according to the embodiment. As shown in FIG. 5A, in the primary sealing body 121 </ b> B according to the comparative example, the thickness t <b> 1 of the first resin layer 23 is larger than the thickness t <b> 2 of the second resin layer 24. In contrast, as illustrated in FIG. 5B, in the primary sealing body 21 </ b> B according to the embodiment, the thickness t <b> 1 of the first resin layer 23 is smaller than the thickness t <b> 2 of the second resin layer 24. For this reason, the volume of the primary sealing body 21B is smaller than the volume of the primary sealing body 121B by the space S having the upper surface of the exposed region 23c as the bottom surface.

  Thus, since the thickness t1 is smaller than the thickness t2 in the power storage module 4, the internal space V is expanded by the space S compared to the comparative example in which the thickness t1 is equal to or greater than the thickness t2. Can do. Thereby, the raise of the pressure of the internal space V by generation | occurrence | production of gas can be suppressed. As a result, it is possible to suppress problems such as abnormal operation of the safety valve and leakage of the electrolyte due to peeling of the joint between the primary sealing body 21B and the outer edge 15c. Moreover, the usage-amount of the pressure rise inhibitor added to an electrode active material and electrolyte solution can be reduced. Furthermore, the SOC (State Of Charge) area can be expanded.

  In the power storage module 4, the outer edge 23 a of the first resin layer 23 coincides with the outer edge 24 a of the second resin layer 24 as viewed from the stacking direction D. For this reason, since the position of the end surface on the outer edge portion 21b side of the primary sealing body 21B is aligned, a gap is generated between the end surface on the outer edge portion 21b side of the primary sealing body 21B and the inner surface 22a of the secondary sealing body 22. hard. Thereby, the joint strength of the primary sealing body 21B and the secondary sealing body 22 can be improved.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

  FIG. 6 is a main part enlarged schematic view showing the configuration of the sealed body of the power storage module according to the modification. As shown in FIG. 6, in the power storage module 4A according to the modification, the first resin layer 23 and the second resin layer 24 are configured by a single folded film (resin layer). The module 4 is different from the module 4 (see FIG. 3) and is otherwise identical to the power storage module 4. The first resin layer 23 and the second resin layer 24 of the primary sealing body 21B are continuous with each other at the outer edge portion 21b (the outer edge portions of the first resin layer 23 and the second resin layer 24). In order to form the primary sealing body 21B, for example, first, a single film is prepared. Then, while joining the part used as the 1st resin layer 23 of a film to the outer edge part 15c by hot press, the 1st resin layer 23 is compressed. Next, the film is folded back at the portion that becomes the outer edge portion 21 b, and the portion that becomes the second resin layer 24 of the film is arranged (laminated) on the first resin layer 23. Thereafter, the second resin layer 24 is welded to the first resin layer 23.

  As described above, in the power storage module 4A, the first resin layer 23 and the second resin layer 24 can be configured by a single folded film. There is no need to prepare separate films.

  In the embodiment, a film having the same thickness is prepared for each of the first resin layer 23 and the second resin layer 24 and the first resin layer 23 is compressed by hot pressing. Also, different thickness films may be prepared for each of the second resin layers 24. If the first resin layer 23 and the second resin layer 24 that satisfy the relationship that the thickness t1 is smaller than the thickness t2 are prepared in advance, the first resin layer 23 may not be compressed by hot pressing.

  In the embodiment, each of the first resin layer 23 and the second resin layer 24 itself has a single layer structure, but may have a laminated structure including a plurality of layers. For example, when the first resin layer 23 has a single-layer structure and the second resin layer 24 has a two-layer structure, the thickness t1 can be easily made smaller than the thickness t2, regardless of hot pressing. In the above modification, the film is folded only once, but it may be folded twice and the second resin layer 24 may have a two-layer structure.

  4, 4A ... Power storage module, 11 ... Electrode laminated body, 12 ... Sealed body, 13 ... Separator, 13a ... Outer edge part, 14 ... Bipolar electrode, 15 ... Electrode plate, 15c ... Outer edge part, 15p ... Projection, 21A, 21B ... primary sealing body, 21b ... outer edge part, 22 ... secondary sealing body, 23 ... first resin layer, 23a ... outer edge, 23c ... exposed region, 24 ... second resin layer, 24a ... outer edge, D ... stacking direction , T1, t2 ... thickness.

Claims (4)

An electrode laminate having a plurality of bipolar electrodes laminated via separators;
A sealing body for sealing between the bipolar electrodes adjacent in the stacking direction in the electrode stack,
The sealing body has a primary sealing body provided at an outer edge portion of the bipolar electrode, and a secondary sealing body provided around the primary sealing body,
The primary sealing body has a first resin layer bonded to an outer edge portion of the bipolar electrode, and a second resin layer laminated on the first resin layer in the lamination direction,
As viewed from the laminating direction, the first resin layer is exposed from the second resin layer, and has an exposed region in which an outer edge portion of the separator is disposed.
In the stacking direction, the thickness of the first resin layer is smaller than the thickness of the second resin layer.   2. The power storage module according to claim 1, wherein an outer edge of the first resin layer coincides with an outer edge of the second resin layer when viewed from the stacking direction.   The power storage module according to claim 2, wherein the first resin layer and the second resin layer are configured by a single folded resin layer. The bonding surface with the first resin layer in the electrode plate constituting the bipolar electrode is a rough plating surface,
The thickness of said 1st resin layer is an electrical storage module as described in any one of Claims 1-3 larger than the largest height of the protrusion in the said roughening plating surface.

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