JP2019036514A - Power storage module and method for manufacturing power storage module - Google Patents

Abstract

To provide a power storage module capable of controlling the height of a step part at highly precisely and a manufacturing method of the power storage module.SOLUTION: A power storage module 12 comprises a cylindrical resin part 50 that is extended in a laminate direction of a bipolar electrode 32, and houses the bipolar electrode 32. The resin part 50 includes a first seal part 52 in which a frame body 60 bonded to a peripheral edge part 34a of an electrode plate 34 is laminated in a laminate direction. The frame body 60 includes: a first frame body 61 bonded to the peripheral edge part 34a of the electrode plate 34; and a second frame body 62 arranged on the first frame body 61. A step part 68 is formed by positioning an inner peripheral end 61c of the first frame body 61 and an inner peripheral end 62c of the second frame body 62 at a position different from each other in a direction intersecting with the lamination direction. A separator 40 is arranged in the step part 68.SELECTED DRAWING: Figure 3

Description

  One aspect of the present invention relates to a power storage module and a method for manufacturing the power storage module.

  A bipolar battery described in Patent Document 1 is known as a secondary battery. In this bipolar battery, a bipolar electrode in which a positive electrode is formed on one surface of a current collector and a negative electrode is formed on the other surface is laminated via an electrolyte layer. A resin seal is provided between the current collectors.

JP 2006-86049 A

  While the separator contained in the electrolyte layer can permeate the electrolytic solution, it is disposed between the adjacent current collectors (electrode plates) to prevent these short circuits. A gap may exist between the separator and the resin seal portion (frame body) in a direction intersecting the stacking direction. If this gap exists, when the electrode plate is deformed for some reason, there is a possibility that a short circuit between adjacent electrode plates may occur through the gap. Such deformation of the electrode plate can occur both when the frame is formed and when internal pressure fluctuations occur during use of the battery.

  Therefore, it is considered that a step portion is formed in the frame body by hot pressing, and the peripheral portion of the separator is disposed at the step portion. In this case, since the separator overlaps the frame in the stacking direction, a short circuit between adjacent electrode plates can be prevented.

  However, when the step portion is formed by hot pressing, if the conditions of the hot pressing are inappropriate, the resin pressed by the hot press may protrude laterally and form a protrusion in the vicinity of the step portion. In this case, since the stepped portion becomes higher by the amount of the protrusion, the height of the stepped portion cannot be controlled with high accuracy.

  An object of one aspect of the present invention is to provide a power storage module that can control the height of a stepped portion with high accuracy and a method for manufacturing the power storage module.

  In a power storage module according to one aspect of the present invention, a plurality of bipolar electrodes each including an electrode plate, a positive electrode provided on a first surface of the electrode plate, and a negative electrode provided on a second surface of the electrode plate include a separator. And a cylindrical resin portion that extends in the stacking direction of the plurality of bipolar electrodes and accommodates the plurality of bipolar electrodes, the resin portion being a peripheral edge of the electrode plate The frame body joined to the part has a first seal part laminated in the laminating direction, and the frame body is joined to the peripheral edge part of the electrode plate, and the first frame body A second frame body disposed on the first frame body, and an inner circumferential edge of the first frame body and an inner circumferential edge of the second frame body are located at different positions in a direction intersecting the stacking direction. A step portion is formed, and the step portion includes the separator. There are located.

  According to this power storage module, since the step portion is formed by the first frame body and the second frame body, the step portion can be formed without using hot pressing. For this reason, since the height of the stepped portion hardly changes when the stepped portion is formed, the height of the stepped portion can be controlled with high accuracy.

  The inner peripheral end of the first frame body may be arranged inside the inner peripheral end of the second frame body. In this case, since there is no obstacle when placing the separator on the first frame in a state where the frame is joined to the peripheral edge of the electrode plate, the separator can be easily disposed on the stepped portion.

  An internal space is formed between the plurality of bipolar electrodes and the resin portion, and the second frame passes through the second frame in a direction intersecting the stacking direction, and the internal space An opening that communicates may be formed. In this case, a pressure regulating valve that operates according to the pressure in the internal space can be connected to the opening of the second frame. When the pressure regulating valve is used, when the pressure in the internal space becomes a predetermined value or more, the pressure regulating valve is opened, and the gas in the internal space can be released to the outside of the power storage module.

  The first frame body may be made of a thermoplastic elastomer. In this case, the sealing performance between the peripheral edge portion of the electrode plate and the first frame body is improved.

  The Young's modulus of the second frame may be greater than the Young's modulus of the first frame. In this case, the handleability of the second frame is improved.

  The resin part has a second seal part provided outside the first seal part in a direction intersecting the stacking direction, and the material constituting the second seal part constitutes the second frame body It may be the same as the material to be used. In this case, the kind of material which comprises a resin part can be decreased.

  The linear expansion coefficient of the first frame may be smaller than the linear expansion coefficient of the second frame. When the linear expansion coefficient of the first frame is reduced, the difference in linear expansion coefficient between the electrode plate and the first frame can be reduced. As a result, the warp of the first frame can be reduced.

  The first frame may include a resin member and a member having a linear expansion coefficient smaller than that of the resin member. Thereby, the linear expansion coefficient of a 1st frame can be made smaller than the linear expansion coefficient of a 2nd frame. The member having a linear expansion coefficient smaller than the linear expansion coefficient of the resin member may be a nonwoven fabric.

  The resin material having the largest mass percentage among the resin materials constituting the first frame may be the same as the resin material having the largest mass percentage among the resin materials constituting the second frame. In this case, the base material of the first frame and the base material of the second frame are the same. In addition, a mass percentage is calculated on the basis of the mass of the whole resin material which comprises a 1st frame or a 2nd frame (100 mass%).

  A method of manufacturing a power storage module according to one aspect of the present invention includes a plurality of bipolar electrodes each including an electrode plate, a positive electrode provided on a first surface of the electrode plate, and a negative electrode provided on a second surface of the electrode plate. Is a method of manufacturing a power storage module laminated via a separator, wherein the bipolar electrode, a first frame joined to a peripheral edge of the electrode plate, and a second arranged on the first frame. A step of preparing an electrode unit having a frame and the separator, a step of laminating the electrode units such that the plurality of bipolar electrodes are laminated via the separator, and the adjacent first frame And a step of preparing the electrode unit, wherein an inner peripheral end of the first frame body and an inner peripheral end of the second frame body intersect a thickness direction of the electrode plate. Different from each other Position and the step portion is formed by in, in the step portion, the separator is arranged.

  According to the method for manufacturing the power storage module, the step portion is formed by the first frame body and the second frame body, and thus the step portion can be formed without using a hot press. For this reason, since the height of the stepped portion hardly changes when the stepped portion is formed, the height of the stepped portion can be controlled with high accuracy.

  According to one aspect of the present invention, a power storage module and a method for manufacturing a power storage module that can control the height of the stepped portion with high accuracy can be provided.

It is a schematic sectional drawing which shows embodiment of an electrical storage apparatus provided with an electrical storage module. It is a schematic sectional drawing which shows the electrical storage module which comprises the electrical storage apparatus of FIG. It is sectional drawing which shows the periphery structure of the resin part in embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2 and corresponds to the first embodiment shown in FIG. 3. It is sectional drawing which shows each process of the manufacturing method of the electrical storage module which concerns on embodiment. It is sectional drawing which shows 1 process of the manufacturing method of the electrical storage module which concerns on embodiment. It is sectional drawing which shows a part of electrical storage module which concerns on a 1st modification. It is sectional drawing which shows a part of electrical storage module which concerns on a 2nd modification. It is sectional drawing which shows a part of electrical storage module which concerns on a 3rd modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and redundant descriptions are omitted. In the drawing, an XYZ orthogonal coordinate system is shown as necessary.

  An embodiment of a power storage device will be described with reference to FIG. The power storage device 10 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 10 includes a plurality (three in the present embodiment) of power storage modules 12, but may include a single power storage module 12. The power storage module 12 is a bipolar battery. The power storage module 12 is a secondary battery such as a nickel hydride secondary battery or a lithium ion secondary battery, but may be an electric double layer capacitor. In the following description, a nickel metal hydride secondary battery is illustrated.

  The plurality of power storage modules 12 can be stacked via a conductive plate 14 such as a metal plate. When viewed from the stacking direction, the power storage module 12 and the conductive plate 14 have, for example, a rectangular shape. Details of each power storage module 12 will be described later. The conductive plates 14 are also arranged outside the power storage modules 12 positioned at both ends in the stacking direction (Z direction) of the power storage modules 12. The conductive plate 14 is electrically connected to the adjacent power storage module 12. Thereby, the some electrical storage module 12 is connected in series in the lamination direction. In the stacking direction, a positive electrode terminal 24 is connected to the conductive plate 14 located at one end, and a negative electrode terminal 26 is connected to the conductive plate 14 located at the other end. The positive terminal 24 may be integrated with the conductive plate 14 to be connected. The negative electrode terminal 26 may be integrated with the conductive plate 14 to be connected. The positive electrode terminal 24 and the negative electrode terminal 26 extend in a direction (X direction) intersecting the stacking direction. The positive and negative terminals 24 and 26 can charge and discharge the power storage device 10.

  The conductive plate 14 can also function as a heat radiating plate for releasing heat generated in the power storage module 12. When a refrigerant such as air passes through the plurality of gaps 14a provided inside the conductive plate 14, heat from the power storage module 12 can be efficiently released to the outside. Each gap 14a extends, for example, in a direction (Y direction) intersecting the stacking direction. When viewed from the stacking direction, the conductive plate 14 is smaller than the power storage module 12, but may be the same as or larger than the power storage module 12.

  The power storage device 10 may include a restraining member 16 that restrains the alternately stacked power storage modules 12 and conductive plates 14 in the stacking direction. The restraining member 16 includes a pair of restraining plates 16A and 16B and a connecting member (bolt 18 and nut 20) for joining the restraining plates 16A and 16B to each other. An insulating film 22 such as a resin film is disposed between the restraining plates 16A and 16B and the conductive plate. Each restraint plate 16A, 16B is comprised, for example with metals, such as iron. When viewed from the stacking direction, each of the restraining plates 16A and 16B and the insulating film 22 has, for example, a rectangular shape. The insulating film 22 is larger than the conductive plate 14, and the restraining plates 16 </ b> A and 16 </ b> B are larger than the power storage module 12. When viewed from the stacking direction, an insertion hole 16A1 through which the shaft portion of the bolt 18 is inserted is provided at a position on the outer side of the power storage module 12 at the edge portion of the restraint plate 16A. Similarly, an insertion hole 16 </ b> B <b> 1 through which the shaft part of the bolt 18 is inserted is provided at a position on the outer side of the power storage module 12 at the edge of the restraint plate 16 </ b> B when viewed from the stacking direction. When each restraint plate 16A, 16B has a rectangular shape when viewed from the stacking direction, the insertion hole 16A1 and the insertion hole 16B1 are located at the corners of the restraint plates 16A, 16B.

  One constraining plate 16A is abutted against the conductive plate 14 connected to the negative terminal 26 via the insulating film 22, and the other constraining plate 16B has the insulating film 22 applied to the conductive plate 14 connected to the positive terminal 24. Has been hit through. For example, the bolt 18 is passed through the insertion hole 16A1 and the insertion hole 16B1 from the one restraint plate 16A side toward the other restraint plate 16B side. A nut 20 is screwed onto the tip of the bolt 18 protruding from the other restraining plate 16B. Accordingly, the insulating film 22, the conductive plate 14, and the power storage module 12 are sandwiched and unitized, and a restraining load is applied in the stacking direction.

  With reference to FIG. 2, a power storage module constituting the power storage device will be described. The power storage module 12 illustrated in FIG. 2 includes a stacked body 30 in which a plurality of bipolar electrodes 32 are stacked. When viewed from the stacking direction of the bipolar electrode 32, the stacked body 30 has, for example, a rectangular shape. A separator 40 may be disposed between the adjacent bipolar electrodes 32.

  Each bipolar electrode 32 includes an electrode plate 34, a positive electrode 36 provided on the first surface 34 c of the electrode plate 34, and a negative electrode 38 provided on the second surface 34 d of the electrode plate 34. In the stacked body 30, the positive electrode 36 of one bipolar electrode 32 faces the negative electrode 38 of one bipolar electrode 32 adjacent in the stacking direction across the separator 40, and the negative electrode 38 of one bipolar electrode 32 connects the separator 40. It faces the positive electrode 36 of the other bipolar electrode 32 that is adjacent in the stacking direction.

  In the stacking direction, an electrode plate 34 having a negative electrode 38 disposed on the inner surface (the lower surface in the drawing) is disposed at one end of the stacked body 30. The electrode plate 34 corresponds to a negative terminal electrode. In the stacking direction, an electrode plate 34 having a positive electrode 36 disposed on the inner surface (the upper surface in the drawing) is disposed at the other end of the stacked body 30. This electrode plate 34 corresponds to a positive terminal electrode. The negative electrode 38 of the negative electrode-side termination electrode faces the positive electrode 36 of the uppermost bipolar electrode 32 with the separator 40 interposed therebetween. The positive electrode 36 of the positive terminal electrode is opposed to the negative electrode 38 of the lowermost bipolar electrode 32 with the separator 40 interposed therebetween. The electrode plates 34 of these termination electrodes are connected to the adjacent conductive plates 14 (see FIG. 1).

  The power storage module 12 includes a cylindrical resin portion 50 that extends in the stacking direction of the bipolar electrodes 32 and accommodates the stacked body 30. The resin part 50 holds the peripheral edge part 34 a of the plurality of electrode plates 34. The resin part 50 is configured to surround the laminated body 30. The resin portion 50 has, for example, a rectangular shape when viewed from the lamination direction of the bipolar electrode 32. That is, the resin part 50 is, for example, a rectangular tube shape.

  The resin part 50 is joined to the peripheral part 34a of the electrode plate 34, and the first seal part 52 that holds the peripheral part 34a and the first seal part 52 in the direction (X direction and Y direction) intersecting the stacking direction. 2nd seal part 54 provided in the outside.

  The first seal portion 52 constituting the inner wall of the resin portion 50 is provided over the entire circumference of the peripheral edge portion 34a of the electrode plate 34 in the plurality of bipolar electrodes 32 (that is, the stacked body 30). The first seal portion 52 is welded, for example, to the peripheral portion 34a of the electrode plate 34, and seals the peripheral portion 34a. That is, the first seal part 52 is joined to the peripheral edge part 34 a of the electrode plate 34. The peripheral edge 34 a of the electrode plate 34 of each bipolar electrode 32 is held in a state of being buried in the first seal portion 52. The peripheral portions 34 a of the electrode plates 34 disposed at both ends of the stacked body 30 are also held in a state of being buried in the first seal portion 52. Thus, an internal space V that is airtightly partitioned by the electrode plates 34 and 34 and the first seal portion 52 is formed between the electrode plates 34 and 34 adjacent in the stacking direction. That is, the internal space V is formed between the bipolar electrode 32 and the resin portion 50. In the internal space V, for example, an electrolytic solution (not shown) made of an alkaline solution such as an aqueous potassium hydroxide solution is accommodated.

  The second seal portion 54 constituting the outer wall of the resin portion 50 covers the outer peripheral surface 52 a of the first seal portion 52 extending in the stacking direction of the bipolar electrode 32. The inner peripheral surface 54a of the second seal portion 54 is welded, for example, to the outer peripheral surface 52a of the first seal portion 52, and seals the outer peripheral surface 52a. That is, the second seal portion 54 is joined to the outer peripheral surface 52 a of the first seal portion 52. The welding surface (joint surface) of the second seal portion 54 with respect to the first seal portion 52 forms, for example, four rectangular planes.

  The electrode plate 34 is a rectangular metal foil made of nickel, for example. The peripheral edge 34a of the electrode plate 34 is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. In the uncoated region, the electrode plate 34 is exposed. The uncoated region is buried and held in the first seal portion 52 constituting the inner wall of the resin portion 50. An example of the positive electrode active material constituting the positive electrode 36 is nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode 38 include a hydrogen storage alloy. The formation region of the negative electrode 38 on the second surface 34 d of the electrode plate 34 may be slightly larger than the formation region of the positive electrode 36 on the first surface 34 c of the electrode plate 34.

  The separator 40 is formed in a sheet shape, for example. The separator 40 has a rectangular shape, for example. Examples of the material forming the separator 40 include porous films, woven fabrics, and nonwoven fabrics made of polyolefin resins such as polyethylene (PE) and polypropylene (PP). The separator 40 may be reinforced with a vinylidene fluoride resin compound. The separator 40 is not limited to a sheet shape, and may be a bag shape.

  The resin portion 50 (the first seal portion 52 and the second seal portion 54) is formed in a rectangular cylindrical shape by, for example, injection molding using an insulating resin. Examples of the resin material constituting the resin portion 50 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and polyphenylene ether (PPE).

  With reference to FIG.3 and FIG.4, the structure of the resin part 50 in 1st Embodiment, the bipolar electrode 32, and the separator 40 is demonstrated. As shown in FIG. 3, the first seal portion 52 of the resin portion 50 is a seal portion in which a plurality of frame bodies 60 are stacked in the stacking direction. Each frame 60 is joined to the peripheral edge 34 a of the electrode plate 34.

  The frame body 60 has a thickness larger than the thickness of the separator 40 in the stacking direction. More specifically, the frame body 60 has a thickness larger than the sum of the thickness of the electrode plate 34 and the thickness of the separator 40 in the stacking direction. The frame body 60 abuts on the peripheral edge 34 a of the electrode plate 34 and abuts on another frame body 60 adjacent in the stacking direction. When the frame body 60 and another frame body 60 come into contact with each other, the frame body 60 defines the height of the internal space V formed between the electrode plates 34 adjacent to each other in the stacking direction. In other words, the frame 60 defines the height of one cell in the power storage module 12.

  Here, the “thickness” of the separator 40 is the thickness of the separator 40 in the power storage module 12. The thickness of the separator 40 in the power storage module 12 can be smaller than the thickness of the separator 40 before the power storage module 12 is assembled. That is, the separator 40 can be compressed by being sandwiched between the positive electrode 36 and the negative electrode 38. The “thickness” of the separator 40 means the thickness after compression.

  The frame body 60 includes a first frame body 61 joined to the peripheral edge 34 a of the electrode plate 34, and a second frame body 62 disposed on the first frame body 61. The first frame 61 is joined to the peripheral edge 34a by welding, for example. In the stacking direction, the first frame body 61 and the second frame body 62 are alternately arranged. The first frame 61 is joined to the first surface 34 c of the electrode plate 34 and is in contact with the outer peripheral end 34 e of the electrode plate 34. An outer peripheral end 34e of the electrode plate 34 connects the first surface 34c and the second surface 34d. The second frame body 62 is disposed on the upper surface 61a of the first frame body 61 (the surface opposite to that bonded to the first surface 34c). The lower surface 62 b of the second frame body 62 is in contact with the upper surface 61 a of the first frame body 61. The upper surface 62 a of the second frame body 62 is in contact with the lower surface 61 b of the adjacent first frame body 61. The first frame body 61 and the second frame body 62 may be connected to each other by partial welding, for example, but the first frame body 61 and the second frame body 62 may not be sealed. This is because the internal space V is kept airtight by the second seal portion 54.

  A stepped portion 68 is formed in the frame 60 because the inner peripheral end 61c of the first frame 61 and the inner peripheral end 62c of the second frame 62 are at different positions in the direction intersecting the stacking direction. . The step portion 68 is configured by the inner peripheral end 61 c and the upper surface 61 a of the first frame body 61 and the inner peripheral end 62 c of the second frame body 62. In the present embodiment, the inner peripheral end 61 c of the first frame body 61 is disposed inside the inner peripheral end 62 c of the second frame body 62. Therefore, the inner peripheral end 61c of the first frame 61 corresponds to the inner peripheral end 52c (see FIG. 2) of the first seal portion 52. The outer peripheral end 61 d of the first frame 61 and the outer peripheral end 62 d of the second frame 62 correspond to the outer peripheral end 52 d (that is, the outer peripheral surface 52 a) of the first seal portion 52.

  The height H of the stepped portion 68 in the stacking direction is the thickness of the second frame 62 (the distance between the upper surface 62a and the lower surface 62b). The height H of the stepped portion 68 is larger than the thickness of the separator 40. In the stepped portion 68, a peripheral portion 40a including the outer peripheral end 40d of the separator 40 is disposed. That is, the stepped portion 68 formed in the frame body 60 faces the inside of the frame body 60, and provides a space for arranging the outer peripheral end 40 d of the separator 40 in the first seal portion 52. . For example, the peripheral portion 40 a of the separator 40 is in contact with the upper surface 61 a of the first frame 61.

  In the power storage module 12, the separator 40 can be compressed in the stacking direction in a region where the positive electrode 36 and the negative electrode 38 are provided. On the other hand, the separator 40 does not receive a pressing force in the stacking direction and is not compressed in the stacking direction in the region facing the uncoated region and the region disposed inside the first seal portion 52. In other words, the separator 40 has play (movable freely) in the stacking direction in the region facing the uncoated region and the region disposed inside the first seal portion 52. With this configuration, the compression portion of the separator 40 can be minimized, and the compression reaction force of the separator 40 can be minimized. As a result, the restraining load on the restraining member 16 can be reduced. Moreover, since the gap of the separator 40 is not inadvertently crushed, the internal space V can be increased. As a result, an increase in internal pressure can be suppressed.

  The size relationship between the size of the separator 40 and the size of the electrode plate 34 may be any relationship. In FIG. 3, the separator 40 is smaller than the electrode plate 34 when viewed from the stacking direction, but may be the same as or larger than the electrode plate 34.

  The linear expansion coefficient of the first frame 61 may be smaller than the linear expansion coefficient of the second frame 62. Although the linear expansion coefficient of the electrode plate 34 is smaller than the linear expansion coefficient of the first frame body 61, the linear expansion coefficient of the first frame body 61 is reduced to reduce the linear expansion coefficient between the electrode plate 34 and the first frame 61. The difference in linear expansion coefficient can be reduced. As a result, the warp of the first frame 61 can be reduced. For example, the first frame 51 includes a resin member and a member having a linear expansion coefficient smaller than the linear expansion coefficient of the resin member. Examples of the resin material constituting the resin member include polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE) as described above. Examples of the member having a linear expansion coefficient smaller than that of the resin member include non-woven fabric, metal, ceramic and the like. The resin material having the largest mass percentage among the resin materials constituting the first frame 61 may be the same as the resin material having the largest mass percentage among the resin materials constituting the second frame 62. Examples of such a resin material include polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE). In this case, the base material (resin member) of the first frame 61 and the base material (resin member) of the second frame 62 are the same.

  The first frame 61 may be made of a thermoplastic elastomer. In this case, the sealing performance between the peripheral edge 34a of the electrode plate 34 and the first frame 61 is improved. As a result, for example, an electrolyte solution made of an alkaline solution such as an aqueous potassium hydroxide solution oozes out to the outer surface side of the electrode plate through a gap between the electrode plate that is the negative terminal electrode and the frame due to a so-called alkali creep phenomenon. Can be suppressed. Examples of the thermoplastic elastomer include a mixture of polypropylene and EPDM (ethylene propylene rubber), a mixture of polypropylene and styrene rubber, and the like.

  The surface of the peripheral edge 34a of the electrode plate 34 may be roughened. For example, the entire surface of the electrode plate 34 may be roughened. The surface of the electrode plate 34 is roughened by, for example, forming a plurality of protrusions by electrolytic plating. When the electrode plate 34 is roughened in this way, a concave portion formed by roughening the first frame 61 fluidized by heat at the bonding interface between the electrode plate 34 and the first frame 61. The anchor effect is exhibited. Thereby, the coupling force between the electrode plate 34 and the first frame 61 can be improved. The protrusion has, for example, a shape that becomes tapered from the proximal end side toward the distal end side. In this case, the cross-sectional shape between adjacent protrusions becomes an undercut shape, and an anchor effect is likely to occur.

  The Young's modulus (bending elastic modulus) of the second frame body 62 may be larger than the Young's modulus of the first frame body 61. In this case, the handleability of the second frame 62 is improved. As a result, the second frame 62 can be easily placed on the first frame 61. The second frame 62 may be made of, for example, polypropylene (PP), polyphenylene ether (PPE), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), thermoplastic elastomer, or the like. When the second frame 62 is made of a thermoplastic elastomer, the ratio of the mass of rubber to the total mass of the thermoplastic elastomer in the thermoplastic elastomer constituting the second frame 62 is the thermoplastic elastomer constituting the first frame 61. It may be smaller than the ratio of the mass of the rubber to the mass of the entire thermoplastic elastomer. Thereby, the Young's modulus of the second frame body 62 can be made larger than the Young's modulus of the first frame body 61.

  The first frame body 61 and the second frame body 62 have a film shape, and the thickness of the second frame body 62 may be smaller than the thickness of the first frame body 61. Thus, even when the thickness of the second frame body 62 is thin, the handling property of the second frame body 62 can be improved by increasing the Young's modulus of the second frame body 62.

  The material constituting the second seal portion 54 may be compatible with the material constituting the second frame body 62, and may be the same as the material constituting the second frame body 62. If the materials are the same, the types of materials constituting the resin portion 50 can be reduced. The second seal portion 54 is made of, for example, modified polyphenylene ether (modified PPE) in order to obtain high rigidity. In this case, if the second frame 62 is also made of modified polyphenylene ether (modified PPE), the types of materials constituting the resin portion 50 can be reduced.

  As shown in FIG. 4, the first frame body 61 and the second frame body 62 are ring-shaped. The second frame 62 may be formed with an opening 62h that penetrates the second frame 62 in a direction intersecting the stacking direction and communicates with the internal space V (see FIG. 2). The opening 62 h communicates with the opening 54 h formed in the second seal portion 54. A pressure regulating valve 70 is fitted in the opening 54h. As a result, the pressure regulating valve 70 is connected to the opening 62h. When the pressure regulating valve 70 is used, the pressure regulating valve 70 is opened when the pressure in the internal space V becomes a predetermined value or more, and the gas in the internal space V can be released to the outside of the power storage module 12.

  As shown in FIG. 4, when viewed from the stacking direction, the peripheral edge 40 a of the separator 40 overlaps the region where the first seal portion 52 is provided. In other words, when the separator 40 and the first seal portion 52 are projected on the plane perpendicular to the stacking direction (XY plane) in the stacking direction, these projected images overlap (ie, overlap). The separator 40 reaches the region where the first seal portion 52 is provided. The outer peripheral end 40 d of the separator 40 is located between the outer peripheral end 52 d and the inner peripheral end 52 c of the first seal portion 52. In FIG. 4, the separator 40 is partially broken so that the configuration of the first seal portion 52 can be easily understood.

  Even in the region near the first seal portion 52 of the electrode plate 34, the separator 40 is provided between the two adjacent electrode plates 34, so that the uncoated region of the adjacent electrode plates 34 does not directly face. In the two adjacent electrode plates 34, the separator 40 always exists between one uncoated region and the other uncoated region. The separator 40 provided so as to overlap the first seal portion 52 prevents two adjacent electrode plates 34 (particularly uncoated areas) from coming into contact with each other and causing a short circuit. The outer peripheral end 40 d may be located between the outer peripheral end 52 d and the inner peripheral end 52 c of the first seal portion 52 over the entire circumference of the separator 40. In a part in the circumferential direction of the separator 40, the outer peripheral end 40 d may be located between the outer peripheral end 52 d and the inner peripheral end 52 c of the first seal portion 52. In the circumferential direction of the separator 40, as the separator 40 overlaps the first seal portion 52 in a larger range, the occurrence of a short circuit can be prevented more reliably.

  As described above, according to the power storage module 12, the stepped portion 68 is formed by the first frame body 61 and the second frame body 62, and thus the stepped portion 68 can be formed without using hot press. Therefore, when the stepped portion 68 is formed, the height H of the stepped portion 68 is unlikely to fluctuate, so that the height H of the stepped portion 68 can be controlled with high accuracy. As a result, the distance between the adjacent electrode plates 34 can be controlled with high accuracy.

  In addition, since the inner peripheral end 61 c of the first frame 61 is disposed on the inner side than the inner peripheral end 62 c of the second frame 62, the frame 60 is joined to the peripheral edge 34 a of the electrode plate 34. When the separator 40 is placed on the first frame 61, there is no obstacle. Therefore, the separator 40 can be easily disposed on the stepped portion 68.

  Next, with reference to FIG.5 and FIG.6, the manufacturing method of the electrical storage module which concerns on embodiment is demonstrated. By this method, the above-described power storage module 12 can be manufactured.

(Preparation process)
First, as shown in FIGS. 5A to 5C, the bipolar electrode 32, the first frame body 61 joined to the peripheral edge 34 a of the electrode plate 34, and the first frame body 61 are arranged. An electrode unit U having the second frame body 62 and the separator 40 is prepared. A stepped portion 68 is formed by the inner peripheral end 61c of the first frame 61 and the inner peripheral end 62c of the second frame 62 being at different positions in the direction intersecting the thickness direction (stacking direction) of the electrode plate 34. Has been. The separator 40 is disposed at the stepped portion 68.

  The electrode unit U is prepared as follows, for example. First, as shown in FIG. 5A, the positive electrode 36 is formed on the first surface 34 c of the electrode plate 34, and the negative electrode 38 is formed on the second surface 34 d of the electrode plate 34 to obtain the bipolar electrode 32. Next, as shown in FIG. 5A, the first frame body 61 is joined to the peripheral edge 34 a of the electrode plate 34. The first frame 61 is welded to the first surface 34c of the electrode plate 34, for example, by pressing the hot plate against the second surface 34d of the electrode plate 34 and performing hot pressing. Thereby, the space between the first frame body 61 and the peripheral edge portion 34a of the electrode plate 34 is sealed. Next, as shown in FIG. 5B, the second frame body 62 is placed on the first frame body 61. Thereby, the step part 68 is formed. The second frame body 62 is partially welded to the first frame body 61, but the space between the first frame body 61 and the second frame body 62 is not sealed. By fixing the second frame body 62 to the first frame body 61, the second frame body 62 is prevented from being displaced with respect to the first frame body 61. Next, as shown in FIG. 5C, the separator 40 is disposed on the stepped portion 68.

  After placing the second frame body 62 on the first frame body 61, the first frame body 61 may be joined to the peripheral edge 34 a of the electrode plate 34. In this case, the stepped portion 68 is formed before the first frame body 61 is joined to the peripheral edge portion 34 a of the electrode plate 34.

(Lamination process)
Next, as shown in FIG. 6, the electrode unit U is stacked such that the plurality of bipolar electrodes 32 are stacked via the separator 40. Thus, the first frame 61 of the adjacent electrode unit U is placed on the second frame 62 of one electrode unit U. The first frame body 61 and the second frame body 62 that are alternately stacked in the stacking direction constitute a first seal portion 52.

(Sealing process)
Next, as shown in FIG. 3, the space between the adjacent first frame bodies 61 is sealed. In the present embodiment, the second seal portion 54 is formed outside the outer peripheral end 52 d of the first seal portion 52. The second seal portion 54 is joined to the first frame body 61 and seals between the adjacent first frame bodies 61. The second seal portion 54 is also joined to the second frame body 62, but may not be joined to the second frame body 62. The second seal portion 54 is formed by, for example, injection molding. For example, the second seal portion 54 can be formed by pouring a resin material of the second seal portion 54 having fluidity into the mold. The second seal portion 54 may be formed, for example, by welding a cylindrical resin member to the outer peripheral end 52d of the first seal portion 52. In welding, for example, the first seal portion 52 and the second seal portion 54 are sandwiched between the first seal portion 52 and the second seal portion 54, and then the first seal portion 52 and the second seal portion 54 are heated. And the second seal portion 54 are welded.

(Liquid injection and sealing process)
Next, an electrolytic solution is injected into the resin portion 50 through a liquid injection port or the like. After injecting the electrolytic solution, the storage module 12 is manufactured by sealing the injection port.

  Thereafter, as shown in FIG. 1, a plurality of power storage modules 12 are stacked via the conductive plate 14. A positive electrode terminal 24 and a negative electrode terminal 26 are connected in advance to the conductive plates 14 located at both ends in the stacking direction. Then, a pair of restraint plates 16A and 16B are respectively arranged at both ends in the stacking direction via the insulating film 22, and the restraint plates 16A and 16B are connected to each other using the bolt 18 and the nut 20. In this way, the power storage device 10 shown in FIG. 1 is manufactured.

  According to the method for manufacturing the power storage module 12 described above, the stepped portion 68 is formed by the first frame body 61 and the second frame body 62, and therefore the stepped portion 68 can be formed without using hot pressing. Therefore, when the stepped portion 68 is formed, the height H of the stepped portion 68 is unlikely to fluctuate, so that the height H of the stepped portion 68 can be controlled with high accuracy.

  FIG. 7 is a cross-sectional view illustrating a part of the power storage module according to the first modification. The storage module 12A shown in FIG. 7 is similar to FIG. 3 except that a gap V1 is formed between the first frame 61, the outer peripheral edge 34e of the electrode plate 34, and the upper surface 62a of the second frame 62. It has the same configuration as the power storage module 12 shown. In the power storage module 12 </ b> A, the first frame 61 is joined to the first surface 34 c of the electrode plate 34, but is not in contact with the outer peripheral end 34 e of the electrode plate 34. Although the lower surface 61b of the first frame 61 is in contact with the upper surface 62a of the second frame 62, it may not be in contact. When the first frame 61 is joined to the peripheral edge 34a of the electrode plate 34 by, for example, heat welding, the resin material constituting the first frame 61 melts and hangs downward. As a result, the first frame 61 has a protrusion 61p protruding downward.

  FIG. 8 is a cross-sectional view showing a part of the power storage module according to the second modification. The power storage module 12B shown in FIG. 8 includes the power storage module 12 shown in FIG. 3 except that the first frame body 161 and the second frame body 162 are provided instead of the first frame body 61 and the second frame body 62. The same configuration is provided. The first frame body 161 and the second frame body 162 constitute a frame body 160. In the power storage module 12 </ b> B, the inner peripheral end 161 c of the first frame 161 is disposed outside the inner peripheral end 162 c of the second frame 162. Therefore, the inner peripheral end 162c of the second frame 162 corresponds to the inner peripheral end 52c (see FIG. 2) of the first seal portion 52. A stepped portion 168 is formed in the frame 160 by the first frame 161 and the second frame 162. The step portion 168 is configured by an inner peripheral end 161 c of the first frame body 161, a lower surface 162 b of the second frame body 162, and an inner peripheral end 162 c of the second frame body 162. A separator 40 is disposed at the stepped portion 168.

  The height H1 of the stepped portion 168 in the stacking direction is the distance from the first surface 34c of the electrode plate 34 to the lower surface 162b of the second frame 162. The height H <b> 1 of the stepped portion 168 is larger than the thickness of the separator 40. In the stepped portion 168, a peripheral portion 40a including the outer peripheral end 40d of the separator 40 is disposed. That is, the step portion 168 formed in the frame body 160 faces the inside of the frame body 160 and provides a space for arranging the outer peripheral end 40 d of the separator 40 in the first seal portion 52. . For example, the peripheral edge portion 40a of the separator 40 is in contact with the lower surface 162b of the second frame body 162.

  In the power storage module 12 </ b> B, the outer peripheral end 40 d of the separator 40 is inserted between the electrode plate 34 and the second frame 162 in a state where the frame body 160 is joined to the peripheral edge 34 a of the electrode plate 34.

  FIG. 9 is a cross-sectional view showing a part of the power storage module according to the third modification. The power storage module 12C illustrated in FIG. 9 has the same configuration as the power storage module 12 illustrated in FIG. 3 except that the second seal portion 154 is provided instead of the second seal portion 54. The second seal portion 154 is formed, for example, by welding the outer peripheral end 61d of the first frame 61 and the outer peripheral end 62d of the second frame 62 together. Examples of the welding method include hot plate welding, hot air welding, and laser welding. In hot plate welding, for example, the second seal portion 154 is formed by pressing the hot plate against the outer peripheral end 61 d of the first frame 61 and the outer peripheral end 62 d of the second frame 62.

  As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment. The configurations of the embodiment and each modification may be arbitrarily combined.

  12, 12A, 12B, 12C ... power storage module, 32 ... bipolar electrode, 34 ... electrode plate, 34a ... peripheral edge, 34c ... first surface, 34d ... second surface, 36 ... positive electrode, 38 ... negative electrode, 40 ... separator, 50 ... Resin part, 52 ... First seal part, 60, 160 ... Frame, 61, 161 ... First frame, 61c, 161c ... Inner peripheral edge, 62, 162 ... Second frame, 62c, 162c ... Inside Peripheral end, 62h ... opening, 68,168 ... stepped portion, U ... electrode unit, V ... internal space.

Claims (11)

A power storage module in which a plurality of bipolar electrodes each including an electrode plate, a positive electrode provided on the first surface of the electrode plate, and a negative electrode provided on the second surface of the electrode plate are stacked via a separator,
Extending in the laminating direction of the plurality of bipolar electrodes, comprising a cylindrical resin portion for accommodating the plurality of bipolar electrodes;
The resin part has a first seal part in which a frame body joined to a peripheral part of the electrode plate is laminated in the lamination direction,
The frame has a first frame joined to the peripheral edge of the electrode plate, and a second frame arranged on the first frame,
The step portion is formed by the inner peripheral end of the first frame and the inner peripheral end of the second frame being at different positions in the direction intersecting the stacking direction,
The power storage module, wherein the separator is disposed at the stepped portion.   The power storage module according to claim 1, wherein the inner peripheral end of the first frame is disposed on an inner side than the inner peripheral end of the second frame. An internal space is formed between the plurality of bipolar electrodes and the resin portion,
3. The power storage module according to claim 1, wherein the second frame has an opening penetrating the second frame in a direction intersecting the stacking direction and communicating with the internal space.   The power storage module according to any one of claims 1 to 3, wherein the first frame body is made of a thermoplastic elastomer.   5. The power storage module according to claim 1, wherein a Young's modulus of the second frame body is larger than a Young's modulus of the first frame body. The resin portion has a second seal portion provided outside the first seal portion in a direction intersecting the stacking direction,
The material which comprises a said 2nd seal | sticker part is an electrical storage module as described in any one of Claims 1-5 which is the same as the material which comprises a said 2nd frame.   The power storage module according to any one of claims 1 to 3, wherein a linear expansion coefficient of the first frame is smaller than a linear expansion coefficient of the second frame.   The power storage module according to claim 7, wherein the first frame body includes a resin member and a member having a linear expansion coefficient smaller than that of the resin member.   The power storage module according to claim 8, wherein the member having a linear expansion coefficient smaller than that of the resin member is a nonwoven fabric.   The resin material having the largest mass percentage among the resin materials constituting the first frame is the same as the resin material having the largest mass percentage among the resin materials constituting the second frame. The electrical storage module as described in any one of -9. A method of manufacturing a power storage module in which a plurality of bipolar electrodes each including an electrode plate, a positive electrode provided on a first surface of the electrode plate, and a negative electrode provided on a second surface of the electrode plate are stacked via a separator. There,
Preparing an electrode unit having the bipolar electrode, a first frame joined to a peripheral portion of the electrode plate, a second frame arranged on the first frame, and the separator;
Laminating the electrode units such that the bipolar electrodes are laminated via the separator;
Sealing between the adjacent first frame bodies;
Including
In the step of preparing the electrode unit, the step portion is formed by the inner peripheral end of the first frame and the inner peripheral end of the second frame being at different positions in the direction intersecting the thickness direction of the electrode plate. Is formed, and the separator is disposed at the step portion.

Images