WO2019031087A1

WO2019031087A1 - Electricity storage module and method for manufacturing electricity storage module

Info

Publication number: WO2019031087A1
Application number: PCT/JP2018/024205
Authority: WO
Inventors: 中村　知広; 祐貴中條; 正博山田; 貴之弘瀬; 耕二郎田丸; 伸烈芳賀; 素宜奥村; 卓郎菊池; 秀典 ▲高▼橋
Original assignee: 株式会社豊田自動織機
Priority date: 2017-08-10
Filing date: 2018-06-26
Publication date: 2019-02-14

Abstract

This electricity storage module is provided with: a plurality of bipolar electrodes which are laminated together with a separator therebetween; and a tubular resin portion which extends in a laminated direction of the plurality of bipolar electrodes and which houses the plurality of bipolar electrodes. Each of the plurality of bipolar electrodes includes an electrode plate, a positive electrode disposed on a first surface of the electrode plate, and a negative electrode disposed on a second surface of the electrode plate. The resin portion includes a seal portion comprising a plurality of frame bodies laminated in the laminated direction. Each of the plurality of frame bodies is joined to a peripheral portion of the electrode plate. At least one of the plurality of frame bodies includes a first frame body joined to the peripheral portion of the electrode plate, and a second frame body disposed on the first frame body. A step portion is formed due to an inner peripheral end of the first frame body and an inner peripheral end of the second frame body being located at different positions in a direction intersecting the laminated direction. The separator is disposed at the step portion.

Description

Power storage module and method of manufacturing power storage module

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

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

JP, 2006-86049, A

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

Therefore, it is considered to form a stepped portion in the frame by heat pressing, and to arrange the peripheral portion of the separator in the stepped portion. In this case, since the separators overlap the frame in the stacking direction, it is possible to prevent a short circuit between adjacent electrode plates.

However, in the case of forming the stepped portion by heat press, if the conditions of the heat press are not appropriate, the resin pressed by the heat press may extend sideways to form a protrusion in the vicinity of the stepped portion. In this case, the height of the step portion can not be controlled with high accuracy because the step portion is increased by the amount of the protrusion.

An object of one aspect of the present invention is to provide a storage module capable of controlling the height of a stepped portion with high accuracy and a method of manufacturing the storage module.

A storage module according to one aspect of the present invention includes a cylindrical resin portion that extends in the stacking direction of a plurality of bipolar electrodes stacked through a separator and the plurality of bipolar electrodes, and accommodates the plurality of bipolar electrodes. And each of the plurality of bipolar electrodes includes 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, and the resin portion is A sealing portion including a plurality of frames stacked in the stacking direction, each of the plurality of frames being joined to a peripheral portion of the electrode plate, and at least one of the plurality of frames; A first frame joined to the peripheral edge of the electrode plate, and a second frame disposed on the first frame, the inner circumferential end of the first frame and the first frame In the direction in which the inner peripheral ends of the two frames cross the stacking direction, Stepped portions by in a position is formed, on the step portion, the separator is arranged.

According to this storage module, since the step portion is formed by the first frame and the second frame, the step portion can be formed without using a heat press. Therefore, when forming the stepped portion, the height of the stepped portion hardly changes, so that the height of the stepped portion can be controlled with high accuracy.

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

An internal space is formed between the plurality of bipolar electrodes and the resin portion, and the second frame penetrates the second frame in a direction intersecting the stacking direction, and the internal space is formed in the second frame. A communicating opening may be formed. In this case, a pressure control valve that operates according to the pressure in the internal space can be connected to the opening of the second frame. When the pressure control valve is used, when the pressure in the internal space reaches a predetermined value or more, the pressure control valve is opened, and the gas in the internal space can be discharged to the outside of the storage module.

The first frame may include a thermoplastic elastomer. In this case, the sealability between the peripheral portion of the electrode plate and the first frame 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 seal portion is a first seal portion, and the resin portion has a second seal portion provided outside the first seal portion in a direction intersecting the stacking direction, and the second seal portion is configured. The material to be formed may be the same as the material constituting the second frame. 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 warpage of the first frame can be reduced.

The first frame may have a resin member and a member having a linear expansion coefficient smaller than the linear expansion coefficient of the resin member. Thereby, the linear expansion coefficient of the first frame can be made smaller than the linear expansion coefficient of the second frame. The member having a linear expansion coefficient smaller than the linear expansion coefficient of the resin member may be a non-woven 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. The mass percentage is calculated based on the mass of the entire resin material constituting the first frame or the second frame (100% by mass).

A method of manufacturing a storage module according to one aspect of the present invention is a method of manufacturing a storage module including a plurality of bipolar electrodes stacked via a separator, wherein each of the plurality of bipolar electrodes includes an electrode plate and the electrode plate. The manufacturing method is a step of preparing a plurality of electrode units, each of the plurality of electrode units being a positive electrode provided on the first surface of the electrode and a negative electrode provided on the second surface of the electrode plate And one of the plurality of bipolar electrodes, a first frame joined to a peripheral portion of the electrode plate, a second frame disposed on the first frame, and the separator. And laminating the plurality of electrode units such that the plurality of bipolar electrodes are stacked via the separator, and sealing between the adjacent first frames. And in the step of preparing the plurality of electrode units, the inner peripheral end of the first frame and the inner peripheral end of the second frame are different from each other in a direction intersecting the thickness direction of the electrode plate. A stepped portion is formed by being in the position, and the separator is disposed in the stepped portion.

According to the method of manufacturing the storage module, since the step portion is formed by the first frame and the second frame, the step portion can be formed without using a heat press. Therefore, when forming the stepped portion, the height of the stepped portion hardly changes, so that the height of the stepped portion can be controlled with high accuracy.

According to one aspect of the present invention, there can be provided a storage module and a method of manufacturing the storage module capable of controlling the height of the stepped portion with high accuracy.

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 cross-sectional view taken along line IV-IV of FIG. 2 and corresponds to the 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 the overlapping description is omitted. In the drawings, an XYZ orthogonal coordinate system is shown as needed.

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

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

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

The storage device 10 may include a restraint member 16 for restraining the storage modules 12 and the conductive plates 14 stacked alternately in the stacking direction. The constraining member 16 includes a pair of constraining

plates

16A and 16B and a connecting member (bolt 18 and nut 20) that interconnects the constraining

plates

16A and 16B. An insulating film 22 such as a resin film, for example, is disposed between the

restraint plates

16A and 16B and the conductive plate 14. Each

restraint plate

16A, 16B is made of, for example, a metal such as iron. When viewed from the stacking direction, each of the

restraint plates

16A, 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 restraint plates 16 </ b> A and 16 </ b> B are larger than the storage module 12. As viewed in the stacking direction, an insertion hole 16A1 for inserting the shaft of the bolt 18 is provided at a position outside the storage module 12 at the edge of the restraint plate 16A. Similarly, as viewed in the stacking direction, an insertion hole 16B1 for inserting the shaft of the bolt 18 is provided at a position outside the storage module 12 at the edge of the restraint plate 16B. When the

restraint plates

16A and 16B have a rectangular shape when viewed from the stacking direction, the insertion holes 16A1 and the insertion holes 16B1 are located at the corners of the

restraint plates

16A and 16B.

One restraint plate 16A is abutted against the conductive plate 14 connected to the negative electrode terminal 26 via the insulating film 22, and the other restraint plate 16B is attached to the conductive plate 14 connected to the positive electrode terminal 24. It is hit through. The bolt 18 is passed through the insertion hole 16A1 and the insertion hole 16B1 from, for example, one restraint plate 16A to the other restraint plate 16B. A nut 20 is screwed into the tip of a bolt 18 projecting from the other restraint plate 16B. Thus, the insulating film 22, the conductive plate 14, and the storage module 12 are sandwiched to form a unit, and a restraint 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 storage module 12 shown in FIG. 2 includes a stacked body 30 including a plurality of stacked bipolar electrodes 32. As viewed from the stacking direction of the bipolar electrodes 32, the stacked body 30 has, for example, a rectangular shape. A separator 40 may be disposed between adjacent bipolar electrodes 32.

Each bipolar electrode 32 includes an electrode plate 34, a positive electrode 36 provided on a first surface 34c of the electrode plate 34, and a negative electrode 38 provided on a second surface 34d of the electrode plate 34. In the laminated 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 with the separator 40 interposed therebetween, and the negative electrode 38 of one bipolar electrode 32 It opposes the positive electrode 36 of the other bipolar electrode 32 which adjoins in the lamination direction on both sides.

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

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

The resin portion 50 is joined to the peripheral portion 34a of the electrode plate 34, and the first seal portion 52 which holds the peripheral portion 34a, and the first seal portion 52 in the direction (X direction and Y direction) intersecting the laminating direction. And a second seal portion 54 provided on the outside of the

The first seal portion 52 constituting the inner wall of the resin portion 50 is provided over the entire circumference of the peripheral portion 34 a of the electrode plate 34 in the plurality of bipolar electrodes 32 (or the stacked body 30). The first seal portion 52 is welded, for example, to the peripheral portion 34 a of the electrode plate 34, and seals the peripheral portion 34 a. That is, the first seal portion 52 is joined to the peripheral portion 34 a of the electrode plate 34. The peripheral portion 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 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. An 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) containing an alkaline solution such as a potassium hydroxide aqueous 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. The second seal portion 54 is joined to the outer peripheral surface 52 a of the first seal portion 52. The welding surface (bonding surface) of the second seal portion 54 with respect to the first seal portion 52 has, for example, four rectangular flat surfaces.

The electrode plate 34 is, for example, a rectangular metal foil containing nickel. The peripheral portion 34 a of the electrode plate 34 is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. The electrode plate 34 is exposed in the uncoated area. The uncoated area is embedded in and held by the first seal portion 52 that constitutes the inner wall of the resin portion 50. As a positive electrode active material which comprises the positive electrode 36, nickel hydroxide is mentioned, for example. As a negative electrode active material which comprises the negative electrode 38, a hydrogen storage alloy is mentioned, for example. The formation region of the negative electrode 38 in the second surface 34 d of the electrode plate 34 may be one size larger than the formation region of the positive electrode 36 in the first surface 34 c of the electrode plate 34.

The separator 40 is formed, for example, in a sheet shape. The separator 40 has, for example, a rectangular shape. As a material for forming the separator 40, a porous film, a woven fabric, a non-woven fabric or the like containing a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is exemplified. The separator 40 may be a separator reinforced with a vinylidene fluoride resin compound. The separator 40 is not limited to a sheet, and a bag-shaped separator may be used.

The resin portion 50 (the first seal portion 52 and the second seal portion 54) is formed in a rectangular cylindrical shape, for example, by 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).

The structures of the resin portion 50 and the bipolar electrode 32 and the separator 40 in the embodiment will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, the first seal portion 52 of the resin portion 50 is a seal portion including a plurality of frames 60 stacked in the stacking direction. Each frame 60 is joined to the peripheral edge 34 a of the electrode plate 34.

The frame 60 has a thickness greater than the thickness of the separator 40 in the stacking direction. More specifically, the frame 60 has a thickness greater than the sum of the thickness of the electrode plate 34 and the thickness of the separator 40 in the stacking direction. The frame 60 abuts on the peripheral portion 34 a of the electrode plate 34 and abuts on another frame 60 adjacent in the stacking direction. When the frame 60 and another frame 60 abut on each other, the frame 60 defines the height of the internal space V formed between the electrode plates 34 adjacent in the stacking direction. In other words, the frame 60 defines the height of one cell in the storage module 12.

The “thickness” of the separator 40 here is the thickness of the separator 40 in the storage module 12. The thickness of the separator 40 in the storage module 12 may be smaller than the thickness of the separator 40 before the 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 60 has a first frame 61 joined to the peripheral edge portion 34 a of the electrode plate 34 and a second frame 62 disposed on the first frame 61. The first frame 61 is joined to the peripheral portion 34 a by welding, for example. In the stacking direction, the first frames 61 and the second frames 62 are alternately arranged. The first frame 61 is joined to the first surface 34 c of the electrode plate 34 and abuts on the outer peripheral end 34 e of the electrode plate 34. The outer peripheral end 34e of the electrode plate 34 connects the first surface 34c and the second surface 34d. The second frame 62 is disposed on the upper surface 61 a (the surface opposite to the surface joined to the first surface 34 c) of the first frame 61. The lower surface 62 b of the second frame 62 is in contact with the upper surface 61 a of the first frame 61. The upper surface 62 a of the second frame 62 is in contact with the lower surface 61 b of the adjacent first frame 61. The first frame 61 and the second frame 62 may be connected to each other, for example, by partial welding, but the space between the first frame 61 and the second frame 62 may not be sealed. This is because the second seal portion 54 keeps the internal space V airtight.

A step portion 68 is formed in the frame 60 by the inner peripheral end 61 c of the first frame 61 and the inner peripheral end 62 c of the second frame 62 being at mutually different positions in the direction intersecting the stacking direction. . The stepped portion 68 is constituted by the inner peripheral end 61 c and the upper surface 61 a of the first frame 61 and the inner peripheral end 62 c of the second frame 62. In the present embodiment, the inner peripheral end 61 c of the first frame 61 is disposed inside the inner peripheral end 62 c of the second frame 62. Therefore, the inner peripheral end 61 c of the first frame 61 corresponds to the inner peripheral end 52 c (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 (i.e., the outer peripheral surface 52 a) of the first seal portion 52.

The height H of the step portion 68 in the stacking direction is the thickness of the second frame 62 (the distance between the upper surface 62 a and the lower surface 62 b). The height H of the step portion 68 is larger than the thickness of the separator 40. In the step portion 68, a peripheral portion 40a including the outer peripheral end 40d of the separator 40 is disposed. That is, the step portion 68 formed in the frame 60 faces the inner side of the frame 60, and provides a space for arranging the outer peripheral end 40d 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 storage module 12, the separator 40 can be compressed in the stacking direction in the region where the positive electrode 36 and the negative electrode 38 are provided. On the other hand, the separator 40 does not receive the 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 (free movement) in the stacking direction in the area facing the uncoated area and in the area 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 restraint load on the restraint member 16 can be reduced. In addition, since the air gap of the separator 40 is not crushed carelessly, the internal space V can be made large. As a result, an increase in internal pressure can be suppressed.

The magnitude 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 in 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. The linear expansion coefficient of the electrode plate 34 is smaller than the linear expansion coefficient of the first frame 61, but by reducing the linear expansion coefficient of the first frame 61, the electrode plate 34 and the first frame 61 may be separated. The difference in linear expansion coefficient can be reduced. As a result, the warpage 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), and modified polyphenylene ether (modified PPE) as described above. As a member which has a linear expansion coefficient smaller than the linear expansion coefficient of a resin member, a nonwoven fabric, a metal, a ceramic etc. are mentioned, for example. 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. As such a resin material, for example, polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE), etc. may be mentioned. 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 include a thermoplastic elastomer. In this case, the sealability between the peripheral portion 34 a of the electrode plate 34 and the first frame 61 is improved. As a result, for example, the electrolytic solution containing an alkaline solution such as an aqueous solution of potassium hydroxide exudes to the outer surface side of the electrode plate through the gap between the electrode plate which is the negative electrode side termination electrode and the frame due to a so-called alkaline creep phenomenon. Can be suppressed. As a thermoplastic elastomer, the mixture of a polypropylene and EPDM (ethylene propylene rubber), the mixture of a polypropylene and a styrene rubber, etc. are mentioned, for example.

The surface of the peripheral portion 34 a 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. As described above, when the electrode plate 34 is roughened, at the bonding interface between the electrode plate 34 and the first frame 61, a recess in which the first frame 61 fluidized by heat is formed by the roughening. Go inside and 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 thicker in the direction from the proximal side to the distal side. In this case, the cross-sectional shape between the adjacent protrusions is an undercut shape, and an anchor effect is likely to occur.

The Young's modulus (bending elastic modulus) of the second frame 62 may be larger than the Young's modulus of the first frame 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 contain, for example, polypropylene (PP), polyphenylene ether (PPE), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE), a thermoplastic elastomer, or the like. When the second frame 62 includes a thermoplastic elastomer, the ratio of the mass of rubber to the mass of the entire 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 rubber to the mass of the whole thermoplastic elastomer in. Thereby, the Young's modulus of the second frame 62 can be made larger than the Young's modulus of the first frame 61.

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

The material forming the second seal portion 54 may have compatibility with the material forming the second frame 62, and may be the same as the material forming the second frame 62. If the material is the same, the types of materials constituting the resin portion 50 can be reduced. The second seal portion 54 contains, for example, modified polyphenylene ether (modified PPE) in order to obtain high rigidity. In this case, when the second frame 62 also contains the 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 61 and the second frame 62 are ring-shaped. The second frame 62 may have an opening 62 h penetrating the second frame 62 in a direction intersecting the stacking direction and communicating 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 control valve 70 is fitted in the opening 54 h. As a result, the pressure control valve 70 is connected to the opening 62 h. When the pressure control valve 70 is used, the pressure control valve 70 can be opened when the pressure in the internal space V becomes equal to or higher than a predetermined value, and the gas in the internal space V can be discharged to the outside of the storage module 12.

As shown in FIG. 4, when viewed in the stacking direction, the peripheral portion 40 a of the separator 40 overlaps the area where the first seal portion 52 is provided. In other words, when the separator 40 and the first seal portion 52 are projected in the stacking direction on a plane (XY plane) perpendicular to the stacking direction, these projected images overlap (that is, overlap). The separator 40 reaches the area 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, a portion of the separator 40 is shown as broken so that the configuration of the first seal portion 52 can be easily understood.

Also in the region near the first seal portion 52 of the electrode plate 34, the separator 40 is provided between two adjacent electrode plates 34, so the uncoated regions of the adjacent electrode plates 34 do not directly face each other. In two adjacent electrode plates 34, a separator 40 is always present between one uncoated region and the other uncoated region. The separator 40 provided so as to overlap the first seal portion 52 prevents the occurrence of a short circuit due to contact between two adjacent electrode plates 34 (in particular, an uncoated region). 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 all around the separator 40. In a part of the separator 40 in the circumferential direction, the outer circumferential end 40 d may be located between the outer circumferential end 52 d and the inner circumferential end 52 c of the first seal portion 52. As the separator 40 overlaps the first seal portion 52 in a large range in the circumferential direction of the separator 40, the occurrence of a short circuit can be more reliably prevented.

As described above, according to the storage module 12, the stepped portion 68 is formed by the first frame 61 and the second frame 62. Therefore, the stepped portion 68 can be formed without using a heat press. Therefore, when forming the stepped portion 68, the height H of the stepped portion 68 is unlikely to change, so the height H of the stepped portion 68 can be controlled with high accuracy. As a result, the distance between 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 placing the separator 40 on the first frame 61, there is no obstacle. Therefore, the separator 40 can be easily disposed in the step 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. The above-described storage module 12 can be manufactured by this method.

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

The electrode unit U is prepared, for example, as follows. First, as shown in FIG. 5A, the positive electrode 36 is formed on the first surface 34c of the electrode plate 34, and the negative electrode 38 is formed on the second surface 34d of the electrode plate 34 to obtain the bipolar electrode 32. . Next, as shown in (a) of FIG. 5, the first frame 61 is joined to the peripheral portion 34 a of the electrode plate 34. The first frame 61 is welded to the first surface 34 c of the electrode plate 34 by, for example, pressing the heat plate against the second surface 34 d of the electrode plate 34 and performing heat pressing. Thereby, the space between the first frame 61 and the peripheral portion 34 a of the electrode plate 34 is sealed. Next, as shown in (b) of FIG. 5, the second frame 62 is placed on the first frame 61. Thereby, the stepped portion 68 is formed. The second frame 62 is partially welded to the first frame 61, but the space between the first frame 61 and the second frame 62 is not sealed. By fixing the second frame 62 to the first frame 61, displacement of the second frame 62 relative to the first frame 61 is suppressed. Next, as shown in (c) of FIG. 5, the separator 40 is disposed at the stepped portion 68.

After the second frame 62 is placed on the first frame 61, the first frame 61 may be joined to the peripheral edge 34 a of the electrode plate 34. In this case, the step portion 68 is formed before the first frame 61 is joined to the peripheral 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. Thereby, 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 61 and the second frame 62 alternately stacked in the stacking direction constitute a first seal portion 52.

(Sealing process)
Next, as shown in FIG. 3, the adjacent first frames 61 are sealed. In the present embodiment, the second seal portion 54 is formed on the outer side of the outer peripheral end 52 d of the first seal portion 52. The second seal portion 54 is joined to the first frame 61 and seals between the adjacent first frames 61. The second seal portion 54 is also joined to the second frame 62, but may not be joined to the second frame 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 the 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 52 d of the first seal portion 52. In welding, for example, after the first seal portion 52 and the second seal portion 54 are heated with the heat plate interposed between the first seal portion 52 and the second seal portion 54, the heat plate is removed and the first seal portion 52 is removed. And the second seal portion 54 are welded.

(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 port 12 is manufactured by sealing the liquid injection port.

Thereafter, as shown in FIG. 1, the plurality of storage modules 12 are stacked via the conductive plate 14. The positive electrode terminal 24 and the negative electrode terminal 26 are connected in advance to the conductive plates 14 positioned at both ends in the stacking direction. Thereafter, a pair of

restraint plates

16A and 16B are disposed 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 bolts 18 and the nuts 20. Thus, power storage device 10 shown in FIG. 1 is manufactured.

According to the method of manufacturing the storage module 12 described above, since the step portion 68 is formed by the first frame 61 and the second frame 62, the step portion 68 can be formed without using a heat press. Therefore, when forming the stepped portion 68, the height H of the stepped portion 68 is unlikely to change, so the height H of the stepped portion 68 can be controlled with high accuracy.

FIG. 7 is a cross-sectional view showing a part of a storage module according to a first modification. The storage module 12A shown in FIG. 7 is the same as the storage module 12A in FIG. 3 except that a space V1 is formed between the first frame 61, the outer peripheral end 34e of the electrode plate 34 and the upper surface 62a of the second frame 62. It has the same configuration as the storage module 12 shown. In the storage module 12A, the first frame 61 is joined to the first surface 34c of the electrode plate 34, but is not in contact with the outer peripheral end 34e of the electrode plate 34. The lower surface 61b of the first frame 61 is in contact with the upper surface 62a of the second frame 62, but may not be in contact with the upper surface 62a. When the first frame 61 is joined to the peripheral portion 34 a of the electrode plate 34 by, for example, thermal welding, the resin material constituting the first frame 61 melts and sags downward. As a result, the first frame 61 has a protrusion 61 p that protrudes downward.

FIG. 8 is a cross-sectional view showing a part of a storage module according to a second modification. The storage module 12B shown in FIG. 8 is different from the storage module 12 shown in FIG. 3 in that the first frame 161 and the second frame 162 are provided instead of the first frame 61 and the second frame 62. It has the same configuration. The first frame 161 and the second frame 162 constitute a frame 160. In the storage module 12B, the inner peripheral end 161c of the first frame 161 is disposed outside the inner peripheral end 162c of the second frame 162. Accordingly, the inner peripheral end 162c of the second frame body 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 stepped portion 168 is constituted by the inner peripheral end 161 c of the first frame 161, the lower surface 162 b of the second frame 162, and the inner peripheral end 162 c of the second frame 162. A separator 40 is disposed at the stepped portion 168.

The height H1 of the step 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 1 of the step 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 160 faces the inside of the frame 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 portion 40 a of the separator 40 is in contact with the lower surface 162 b of the second frame 162.

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

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

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited to the above embodiments. The configurations of the embodiment and each modification may be combined arbitrarily.

12, 12A, 12B, 12C: storage module, 32: bipolar electrode, 34: electrode plate, 34a: peripheral portion, 34c: first surface, 34d: second surface, 36: positive electrode, 38: negative electrode, 40: separator, DESCRIPTION OF SYMBOLS 50 ... Resin part, 52 ... 1st seal part, 60, 160 ... Frame, 61, 161 ... 1st frame, 61c, 161c ... Inner peripheral end, 62, 162 ... 2nd frame, 62c, 162c ... Inside Peripheral end, 62 h ... opening, 68, 168 ... stepped portion, U ... electrode unit, V ... internal space.

Claims

A plurality of bipolar electrodes stacked via a separator,
A tubular resin portion extending in the stacking direction of the plurality of bipolar electrodes and accommodating the plurality of bipolar electrodes;
Equipped with
Each of the plurality of bipolar electrodes includes 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,
The resin portion has a seal portion including a plurality of frames stacked in the stacking direction, and each of the plurality of frames is joined to a peripheral portion of the electrode plate.
At least one frame of the plurality of frames includes a first frame joined to the peripheral edge of the electrode plate and a second frame disposed on the first frame.
A stepped portion is formed by the inner circumferential end of the first frame and the inner circumferential end of the second frame being at mutually different positions in the direction intersecting the stacking direction,
A 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 inside the inner peripheral end of the second frame.
An internal space is formed between the plurality of bipolar electrodes and the resin portion,
The power storage module according to claim 1, wherein an opening communicating with the internal space is formed in the second frame through the second frame in a direction intersecting the stacking direction.
The power storage module according to any one of claims 1 to 3, wherein the first frame includes a thermoplastic elastomer.
The power storage module according to any one of claims 1 to 4, wherein a Young's modulus of the second frame is larger than a Young's modulus of the first frame.
The seal portion is a first seal portion,
The resin portion has a second seal portion provided on the outer side of the first seal portion in a direction intersecting the stacking direction,
The power storage module according to any one of claims 1 to 5, wherein a material forming the second seal portion is the same as a material forming the second 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 a linear expansion coefficient of the resin member.
The power storage module according to claim 8, wherein the member having a linear expansion coefficient smaller than a linear expansion coefficient of the resin member is a non-woven fabric.
The resin material having the largest mass percentage of the resin materials constituting the first frame is the same as the resin material having the largest mass percentage of the resin materials constituting the second frame. The storage module according to any one of to 9.
A method of manufacturing a storage module including a plurality of bipolar electrodes stacked via a separator, comprising:
Each of the plurality of bipolar electrodes includes 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,
The manufacturing method is
The step of preparing a plurality of electrode units, wherein each of the plurality of electrode units is one bipolar electrode of the plurality of bipolar electrodes, a first frame joined to the peripheral portion of the electrode plate, and A second frame disposed on the first frame, and the separator,
Laminating the plurality of electrode units such that the plurality of bipolar electrodes are stacked via the separator;
Sealing between the adjacent first frames;
Including
In the step of preparing the plurality of electrode units, the inner peripheral end of the first frame and the inner peripheral end of the second frame are at mutually different positions in the direction intersecting the thickness direction of the electrode plate. A method of manufacturing a storage module, wherein a stepped portion is formed, and the separator is disposed in the stepped portion.