JP6948255B2 - Power storage module and its manufacturing method - Google Patents

Description

The present invention relates to a power storage module and a method for manufacturing the same.

As a conventional power storage module, a bipolar battery including a bipolar electrode having a positive electrode formed on one surface of an electrode plate and a negative electrode formed on the other surface is known. For example, the bipolar battery disclosed in Patent Document 1 includes an electrode laminate in which a plurality of bipolar electrodes are laminated, and a polypropylene cell casing (sealing body) provided on a side surface of the electrode laminate. There is. A polypropylene layer is provided on the edge of the bipolar electrode, and the bipolar electrode and the cell casing are firmly fixed by integral molding via the polypropylene layer. As a result, the electrolytic solution can be sealed.

Japanese Unexamined Patent Publication No. 2005-13576

In the power storage module as described above, when the electrolytic solution is an alkaline aqueous solution, the electrolytic solution is transmitted on the electrode plate of each electrode by the so-called alkaline creep phenomenon, and passes through the gap between the polypropylene layer and the electrode plate. It may seep out to the outer surface side of the electrode plate. If the alkaline creep phenomenon occurs at the outermost electrode, the electrolytic solution leaks to the outside of the system, and even if the alkaline creep phenomenon occurs at the inner electrode, the amount of the electrolytic solution in the cell fluctuates, which is not preferable.

The present invention has been made to solve the above problems, and provides a power storage module capable of reducing leakage of an electrolytic solution.

The power storage module according to one embodiment of the present invention includes an electrode laminate in which a plurality of bipolar electrodes are laminated, and a sealing body that seals the side surfaces of the electrode laminate. The bipolar electrode includes an electrode plate, a positive electrode provided on one surface of the electrode plate, and a negative electrode provided on the other surface of the electrode plate. The encapsulant is provided on each of the bipolar electrodes, and is provided between the annular resin portion provided along the peripheral edge portion of each electrode plate of the bipolar electrode and the peripheral edge portion and the annular resin portion of each electrode plate. It includes a bonded resin layer bonded to the portion and the cyclic resin portion, and a tubular portion surrounding the side surface of the electrode laminate and bonded to each cyclic resin portion. The bonded resin layer and the peripheral edge of the electrode plate are bonded to each other via a chemical bond. According to such a power storage module, since the encapsulant is firmly adhered to the electrode plate by the bonded resin layer, even when the annular resin portion shrinks due to cooling or solidification, the encapsulant and the electrode plate can be bonded to each other. The formation of gaps at the bonding interface can be suppressed. Therefore, leakage of the electrolytic solution can be reduced.

The chemical bond can be a covalent bond or a hydrogen bond.

The bonded resin layer can be an acid-modified polyolefin resin layer, an acrylic resin layer, or a cured product layer of an epoxy resin.

The portion of the peripheral edge of the electrode plate that comes into contact with the bonded resin layer may have protrusions. According to such an aspect, the adhesion between the sealing body and the electrode plate becomes stronger due to the anchor effect, and the formation of a gap at the bonding interface between the sealing body and the electrode plate can be further suppressed. Further, even if a gap is formed at the bonding interface between the sealing body and the electrode plate, if the portion of the peripheral edge of the electrode plate in contact with the bonding resin layer has a protrusion, the surface of the peripheral edge is smooth. Compared to the case, the path length through which the electrolytic solution passes in the gap is longer. Therefore, the leakage of the electrolytic solution can be further reduced.

The electrode laminate includes an electrode plate and a negative electrode provided on one surface of the electrode plate at the outermost side in the lamination direction, and the negative electrode is arranged so that one surface is inside the electrode laminate. Further termination electrodes can be provided. The encapsulant is a negative electrode provided between a negative electrode terminal cyclic resin portion provided along the peripheral edge of the electrode plate of the negative electrode terminal electrode and between the peripheral edge of the electrode plate of the negative electrode terminal electrode and the negative electrode terminal annular resin portion. A termination-bonded resin layer and the like can be further included. The negative electrode terminal annular resin portion is adhered to the tubular portion, and the negative electrode terminal bonding resin layer is adhered to the peripheral edge portion of the electrode plate of the negative electrode terminal electrode and the negative electrode terminal annular resin portion, and the negative electrode terminal bonding resin layer and the negative electrode terminal electrode. It is adhered to the peripheral edge of the electrode plate via a chemical bond.

The negative electrode terminal bond resin layer and the peripheral edge of the electrode plate of the negative electrode terminal electrode can be bonded via a covalent bond or a hydrogen bond.

The method for manufacturing the power storage module according to one embodiment of the present invention includes a step of applying a liquid resin that forms a chemical bond with the electrode plate to the peripheral edge of the electrode plate of the bipolar electrode to form a bonded resin layer. A step of adhering the cyclic resin portion to the bonded resin layer is provided.

According to the present invention, it is possible to provide a power storage module capable of reducing leakage of an electrolytic solution.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a power storage device. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module. FIG. 3 is a schematic cross-sectional view showing the bonding interface between the peripheral edge of the electrode plate and the sealing body. FIG. 4 is a schematic cross-sectional view showing a part of FIG. 2 in an enlarged manner.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same code will be used for the same element or the element having the same function, and duplicate description will be omitted.

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

The power storage module stack 2 is composed of a plurality of (three in this embodiment) power storage modules 4 and a plurality of (four in this embodiment) conductive plates 5. The power storage module 4 is, for example, a bipolar battery provided with a bipolar electrode 14 described later, and has a rectangular shape when viewed from the stacking direction. The power storage module 4 is, for example, a secondary battery such as a nickel hydrogen secondary battery or a lithium ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-metal hydride secondary battery will be illustrated.

The power storage modules 4 and 4 adjacent to each other in the stacking direction are electrically connected to each other via the conductive plate 5. The conductive plates 5 are arranged between the power storage modules 4 and 4 adjacent to each other in the stacking direction and outside the power storage modules 4 located at the stacking ends, respectively. A positive electrode terminal 6 is connected to one of the conductive plates 5 arranged outside the power storage module 4 located at the laminated end. The negative electrode terminal 7 is connected to the other conductive plate 5 arranged outside the power storage module 4 located at the laminated end. The positive electrode terminal 6 and the negative electrode terminal 7 are drawn out from the edge of the conductive plate 5, for example, in a direction intersecting with each other in the stacking direction. The positive electrode terminal 6 and the negative electrode terminal 7 charge and discharge the power storage device 1.

Inside each conductive plate 5, a plurality of flow paths 5a through which a refrigerant such as air flows are provided. Each flow path 5a extends parallel to each other, for example, in a direction orthogonal to the stacking direction and the drawing direction of the positive electrode terminal 6 and the negative electrode terminal 7. By circulating the refrigerant through these flow paths 5a, the conductive plate 5 not only functions as a connecting member for electrically connecting the storage modules 4 and 4 to each other, but also a heat radiating plate that dissipates heat generated by the power storage module 4. It also has the function of. In the example of FIG. 1, the area of the conductive plate 5 seen from the stacking direction is smaller than the area of the power storage module 4, but from the viewpoint of improving heat dissipation, the area of the conductive plate 5 is the area of the power storage module 4. It may be the same as, and may be larger than the area of the power storage module 4.

The restraint member 3 is composed of a pair of end plates 8 and 8 that sandwich the power storage module laminate 2 in the stacking direction, and a fastening bolt 9 and a nut 10 that fasten the end plates 8 and 8 to each other. The end plate 8 is a rectangular metal plate having an area one size larger than the area of the power storage module 4 and the conductive plate 5 when viewed from the stacking direction. A film F having electrical insulation is provided on the inner surface of the end plate 8 (the surface on the side of the storage module laminate 2). The film F insulates between the end plate 8 and the conductive plate 5.

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

Next, the configuration of the power storage module 4 will be described in more detail. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module 4 according to the embodiment. As shown in the figure, the power storage module 4 includes an electrode laminated body 11 and a sealing body 12 that seals the side surface 11a of the electrode laminated body 11.

The electrode laminate 11 has a plurality of bipolar electrodes 14 laminated via a separator 13. In this example, the stacking direction D of the electrode laminated body 11 coincides with the stacking direction of the power storage module laminated body 2. The electrode laminate 11 has a side surface 11a extending in the stacking direction D. The bipolar electrode 14 includes an electrode plate 15, a positive electrode 16 provided on one surface 15a of the electrode plate 15, and a negative electrode 17 provided on the other surface 15b of the electrode plate 15. The positive electrode 16 is a positive electrode active material layer. The negative electrode 17 is a negative electrode active material layer. Examples of the positive electrode active material constituting the positive electrode 16 include nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode 17 include a hydrogen storage alloy. In the electrode laminate 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of one of the bipolar electrodes 14 adjacent to each other in the stacking direction D with the separator 13 interposed therebetween. In the electrode laminate 11, the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of the other bipolar electrode 14 adjacent to each other in the stacking direction D with the separator 13 interposed therebetween.

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

The electrode plate 15 is a metal plate, and examples of the metal plate include a nickel foil and a nickel-plated steel plate. The nickel-plated steel sheet is a steel sheet having nickel plating on its surface. In the present embodiment, the formation region of the negative electrode 17 on the other surface 15b of the electrode plate 15 is one size larger than the formation region of the positive electrode 16 on the one surface 15a of the electrode plate 15.

The peripheral edge portion 15c of the electrode plate 15 is a region in which the positive electrode and the negative electrode are not provided on the peripheral portion 15c, and has a rectangular annular shape when viewed from the stacking direction D.

The separator 13 is formed in a sheet shape, for example. Examples of the material for forming the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric made of polypropylene or the like, or a non-woven fabric. The separator 13 may be reinforced with a vinylidene fluoride resin compound or the like. The separator 13 is not limited to a sheet shape, and a bag shape may be used.

The sealing body 12 has a plurality of annular resin portions 21, a tubular portion 22, and a plurality of bonded resin layers 23, and surrounds the side surface 11a of the electrode laminate 11.

The annular resin portion 21 is a resin film having a thickness in the stacking direction D, and is rectangular and annular when viewed from the stacking direction D.

The annular resin portion 21 is provided on one surface 15a side of each electrode plate 15 of the bipolar electrode 14, the negative electrode termination electrode 18, and the positive electrode termination electrode 19 along the peripheral edge portion 15c.

Each annular resin portion 21 and the peripheral edge portion 15c of each electrode plate 15 are adhered to each other by a bonding resin layer 23 described later. When viewed from the stacking direction D, the outer boundary of each annular resin portion 21 projects outside the outer boundary of the peripheral edge portion 15c of each electrode plate 15, and the inner portion of the annular resin portion 21 overlaps with the peripheral edge portion 15c. The outer portion of the annular resin portion 21 does not overlap with the peripheral edge portion 15c. The outer portion of each annular resin portion 21 is buried in the tubular portion 22, and each annular resin portion 21 and the tubular portion 22 are adhered to each other at their contact surfaces. The annular resin portions 21 and 21 adjacent to each other in the stacking direction D are separated from each other.

The tubular portion 22 is a cylinder having a rectangular opening cross section, which is arranged with the stacking direction D as the axial direction. The tubular portion 22 has a length capable of covering the side surface 11a of the electrode laminated body 11 over the entire length of the electrode laminated body 11 in the stacking direction D, and constitutes an outer wall (housing) of the power storage module 4. .. The inner surface of the tubular portion 22 is adhered to the outer portion of each annular resin portion 21.

The encapsulant 12 is between the bipolar electrodes 14 and 14 adjacent to the stacking direction D, between the negative electrode terminal 18 and the bipolar electrode 14 adjacent to the stacking direction D, and the positive electrode 19 adjacent to the stacking direction D. It is sealed between the bipolar electrode 14 and the bipolar electrode 14. As a result, between the bipolar electrodes 14 and 14 adjacent to each other in the stacking direction D, between the negative electrode terminal 18 and the bipolar electrode 14 adjacent to the stacking direction D, and between the positive electrode terminal 19 and the bipolar electrode 14 adjacent to each other in the stacking direction D. An internal space V that is airtightly partitioned is formed between the two. An electrolytic solution (not shown) is housed in this internal space V. The electrolytic solution is impregnated in the separator 13, the positive electrode 16 and the negative electrode 17. An example of an electrolytic solution is an alkaline aqueous solution such as an aqueous potassium hydroxide solution.

Next, the bonding interface between the peripheral edge portion 15c of the electrode plate 15 and the sealing body 12 will be described. As shown in FIG. 2, a bonding resin layer 23 is provided between the peripheral edge portion 15c of the electrode plate 15 and the cyclic resin portion 21. The bonded resin layer 23 is adhered to the cyclic resin portion 21 and to the peripheral edge portion 15c of the electrode plate 15 via a chemical bond.

The cyclic resin portion 21 can be a molded product of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin-based thermoplastic resins such as polypropylene (PP), polyphenylene ether-based resins such as modified polyphenylene ether (modified PPE), and thermoplastic elastomers. Since the electrolytic solution is alkaline, it is preferable that these resins have resistance to alkali. Examples of polypropylene include homopropylene, block polypropylene (propylene-ethylene block copolymer), and random polypropylene (propylene-ethylene random copolymer). Specific examples of the modified PPE include polymer alloys of polyphenylene ether and other resins, and examples of other resins are polystyrene, polyamide, polypropylene, and polyphenylene sulfide. Modified PPE is sometimes referred to as Zylon®. Examples of the thermoplastic elastomer include a mixture of polypropylene and EPDM (ethylene propylene diene rubber), a mixture of polypropylene and styrene rubber, and the like. The resin constituting the tubular portion 22 may or may not be the same as the resin constituting the annular resin portion 21. From the viewpoint of forming the tubular portion 22 by injection molding and from the viewpoint of alkali resistance, the resin constituting the tubular portion 22 is preferably a thermoplastic resin such as modified PPE.

The bonded resin layer 23 can be in the form of a film, and its thickness is not particularly limited, but is, for example, 0.1 to 50 μm.

The material of the bonded resin layer 23 is not particularly limited as long as it is a resin capable of forming a chemical bond (for example, a covalent bond or a hydrogen bond) with the peripheral edge portion 15c of the electrode plate 15, but the material of the bonded resin layer 23 is an acid group. Examples thereof include an acid-modified polyolefin resin having the above, a cured product of an epoxy resin, and an acrylic resin. An example of an acid-modified polyolefin resin is acid-modified polypropylene. The acid can be a carboxylic acid or a carboxylic acid anhydride, and a specific example of the acid is maleic anhydride. Since the electrolytic solution is alkaline, it is preferable that these resins have resistance to alkali. Specific examples of the acid-modified polyolefin resin include "PPET-1505SG" (manufactured by Toagosei Corporation). Specific examples of the epoxy resin include "2081D" (manufactured by ThreeBond Co., Ltd.).

When the bonded resin layer 23 is an acid-modified polyolefin resin, the acid-modified polyolefin resin has an acid group in the molecule. Therefore, at the interface of the bonded resin layer 23, the acid group in the resin and the peripheral portion 15c of the electrode plate 15 A covalent bond can be formed with the hydroxyl group on the surface. Further, a hydrogen bond may be formed between the acid group in the resin and the hydroxyl group on the surface of the peripheral portion 15c. For example, when the bonded resin layer 23 is a layer of maleic anhydride-modified polyolefin, the maleic anhydride group reacts with the hydroxyl group on the surface of the peripheral portion 15c of the electrode plate 15 at the interface of the bonded resin layer 23 to be anhydrous. Maleic anhydride opens to form a covalent bond as shown in the formula below.

When the bonded resin layer 23 is a cured product of the epoxy resin, the epoxy resin has a large number of ether groups and hydroxyl groups in the molecule. A hydrogen bond is formed between the peripheral portion 15c of the electrode plate 15 and the hydroxyl group on the surface of the peripheral portion 15c.

The materials constituting the cyclic resin portion 21, the tubular portion 22, and the bonded resin layer 23 are all resins, and as the resin, those having compatibility with each other can be used. In this case, the cyclic resin portion 21, the tubular portion 22, and the bonded resin layer 23 can be directly adhered to each other. The cyclic resin portion 21 and the tubular portion 22, and the cyclic resin portion 21 and the bonded resin layer 23 may be adhered to each other via another adhesive layer.

As shown in FIGS. 3A and 3B, the peripheral edge portion 15c can have a protrusion 15p that forms a rough surface at a portion that comes into contact with the bonded resin layer 23. In this case, as shown in FIG. 3A, the thickness of the bonded resin layer 23 may be lower than the height of the protrusions 15p and may be formed along the surface of the protrusions 15p. As shown in the above, the protrusion 15p may be buried at a height higher than the height of the protrusion 15p. The protrusion 15p can be, for example, 2 to 20 μm or 5 to 15 μm.

When the peripheral edge portion 15c has such a protrusion 15p, the adhesion between the annular resin portion 21 and the bonding resin layer 23 and the electrode plate 15 becomes stronger due to the anchor effect, and the adhesive interface between the sealing body 12 and the electrode plate 15 becomes stronger. The formation of gaps in the above can be further suppressed. Further, even if a gap is formed at the bonding interface between the sealing body 12 and the electrode plate 15, the path length through which the electrolytic solution passes in the gap is longer than in the case where the peripheral edge portion 15c is smooth, so that electrolysis is performed. Leakage of liquid can be further reduced. At least, if the surface of the peripheral edge portion 15c on the one surface 15a is a rough surface, the adhesion between the sealing body 12 and the electrode plate 15 is improved.

As shown in FIG. 3, the protrusion 15p can have a shape that becomes thicker from the proximal end side toward the distal end side, for example. In this case, the cross-sectional shape between the adjacent protrusions 15p and 15p is an undercut shape, and the anchor effect is likely to occur. Note that FIG. 3 is a schematic view, and the shape and density of the protrusions 15p are not particularly limited.

Subsequently, the manufacturing method of the power storage module 4 described above will be described. In one embodiment, the method for manufacturing the power storage module 4 includes a primary molding step, a laminating step, a secondary molding step, and an injection step.

In the primary molding step, first, a predetermined number of bipolar electrodes 14, a pair of negative electrode terminal electrodes 18 and positive electrode terminal electrodes 19 are prepared, and an electrode plate 15 is formed on a peripheral edge portion 15c on the at least one surface 15a side of each electrode plate 15. The bonded resin layer 23 is formed using a liquid resin capable of forming a chemical bond (for example, a covalent bond or a hydrogen bond). As a forming method, for example, a liquid resin may be applied and dried / cured. Examples of the liquid resin include an emulsion of acid-modified polyolefin and a curable epoxy resin. The bonded resin layer 23 is obtained by drying the solvent in the case of an emulsion and by curing in the case of a curable epoxy resin.

Next, the thermoplastic cyclic resin portion 21 is adhered onto the bonded resin layer 23. Adhesion is preferably welding such as heat welding or ultrasonic welding. In the case of welding, the cyclic resin portion 21 is temporarily heated and melted on the welded surface, and the welded surface is solidified again by the subsequent cooling. Therefore, the cyclic resin portion 21 may shrink due to cooling or solidification after welding. In the present invention, since the sealing body 12 is firmly adhered to the peripheral edge portion 15c of the electrode plate 15 by the bonded resin layer 23, the sealing body 12 is sealed even when the cyclic resin portion 21 is shrunk due to cooling or solidification. The formation of a gap at the bonding interface between the body 12 and the electrode plate 15 can be suppressed.

In the laminating step, the bipolar electrode 14, the negative electrode terminal electrode 18, and the positive electrode terminal 19 are laminated via the separator 13 so that the annular resin portion 21 is arranged between the peripheral edges 15c of the electrode plate 15. The electrode laminate 11 is formed. In the secondary molding step, after the electrode laminate 11 is placed in the injection molding mold, the molten resin is injected into the mold to form the tubular portion 22 so as to surround the electrode laminate 11. .. At this time, the tubular portion 22 is formed so as to embed the outer portion of the annular resin portion 21, and is welded (adhered) to the outer portion by the heat during injection molding. In the injection step, after the secondary molding step, the electrolytic solution is injected into the internal space V between the bipolar electrodes 14 and 14. As a result, the power storage module 4 is obtained.

The power storage device 1 shown in FIG. 1 includes a step of laminating the obtained power storage module 4 and a conductive plate 5 to form a power storage module stack 2, a step of restraining the power storage module stack 2 by a restraint member 3, and the like. Obtained through.

Subsequently, the effects of the present invention will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing a part of FIG. 2 in an enlarged manner.

In the power storage module 4, the electrolytic solution L is transmitted on the electrode plate 15 due to the so-called alkaline creep phenomenon, passes between the annular resin portion 21 of the sealing body 12 and the electrode plate 15, and is on the one side 15a side of the electrode plate 15. May exude. The alkaline creep phenomenon occurs in each of the bipolar electrodes 14 and the negative electrode termination electrodes 18 in the electrode laminate 11 when the power storage device 1 is charged, discharged, and unloaded due to an electrochemical factor and a fluid phenomenon. In FIG. 4, as an example, the movement path of the electrolytic solution L when the alkaline creep phenomenon occurs in the negative electrode terminal electrode 18 is indicated by an arrow A. The alkaline creep phenomenon is caused by the existence of paths for the negative electrode potential, the electrolytic solution L, and the electrolytic solution L, respectively. In order to suppress the alkaline creep phenomenon, it is conceivable to take measures for the path of the electrolytic solution L. It is presumed that this path is formed as follows. When the cyclic resin portion 21 is welded, the cyclic resin portion 21 is temporarily heated and melted on the welded surface, and the welded surface is solidified again by the subsequent cooling. It is considered that the cyclic resin portion 21 contracts during this solidification and during cooling to room temperature, and a passage is formed between the annular resin portion 21 and the electrode plate 15. Further, when the annular resin portion 21 is heated during the welding of the tubular portion 22, a gap (passage) may be formed in the same manner.

According to the power storage module 4 according to the above embodiment of the present invention, since the cyclic resin portion 21 of the sealing body 12 is firmly adhered to the electrode plate 15 by chemical bonding by the binding resin layer 23, the cyclic resin portion 21 or Even when the cyclic resin portion 21 shrinks due to cooling or solidification after the tubular portion 22 is welded, the formation of a gap (that is, the path of the electrolytic solution L) at the adhesive interface between the sealing body 12 and the electrode plate 15 is suppressed. be able to. Therefore, the alkaline creep phenomenon can be suppressed and the leakage of the electrolytic solution L can be reduced.

The present invention is not limited to the above-described embodiment, and various modifications are possible. The annular resin portion 21 may be provided along the peripheral edge portion 15c so as to cover not only one surface 15a of the electrode plate 15 but also the end surface of the electrode plate 15. In this case, it is preferable that the bonding resin layer 23 is also adhered to the peripheral edge portion 15c so as to cover not only one surface 15a of the electrode plate 15 but also the end surface. By making the adhesive surface between the electrode plate 15 and the sealing body 12 wider in this way, leakage of the electrolytic solution L can be further reduced.

Further, the shape of the annular resin portion 21 is not limited to a rectangular ring as long as it has a hole corresponding to the electrode plate 15 in the central portion, and various forms can be formed according to the shape of the electrode plate 15. ..

Further, in the above embodiment, the binding resin layer 23 is adhered not only to the bipolar electrode 14, but also to the negative electrode terminal electrode 18 and the positive electrode terminal electrode 19, but the negative electrode terminal electrode 18 and the positive electrode terminal electrode 19 When the sealing mode is different from the above, it is not necessary to provide the bonding resin layer 23 between these electrodes and the cyclic resin portion 21.

4 ... Energy storage module, 11 ... Electrode laminate, 11a ... Side surface, 12 ... Encapsulant, 14 ... Bipolar electrode, 15 ... Electrode plate, 15a ... One side, 15b ... Other side, 15c ... Peripheral part, 16 ... Positive electrode, 17 ... Negative electrode, 21 ... Cyclic resin portion, 22 ... Cylindrical portion, 23 ... Bonded resin layer, D ... Lamination direction.

Claims (6)

An electrode laminate in which a plurality of bipolar electrodes are laminated and a sealing body that seals the side surface of the electrode laminate are provided.
The electrode laminate contains an electrolytic solution composed of an alkaline aqueous solution and contains an electrolytic solution.
The bipolar electrode includes an electrode plate, a positive electrode provided on one surface of the electrode plate, and a negative electrode provided on the other surface of the electrode plate.
The sealant is
An annular resin portion provided on each of the bipolar electrodes and provided along the peripheral edge of each electrode plate of the bipolar electrode,
A bonded resin layer provided between the peripheral edge portion and the annular resin portion of each of the electrode plates and adhered to the peripheral edge portion and the annular resin portion.
A tubular portion that surrounds the side surface of the electrode laminate and is adhered to each of the annular resin portions is included.
The bonded resin layer is an acid-modified polyolefin resin layer, and is
The bonded resin layer and the peripheral portion of the electrode plate are adhered to each other via a chemical bond.
The cyclic resin portion is made of a thermoplastic resin containing the bonded resin layer and a resin having compatibility with the tubular portion.
The cyclic resin portion and the bonded resin layer are welded to each other.
The tubular portion is made of a thermoplastic resin containing a resin compatible with the cyclic resin portion.
The cyclic resin portion and the tubular portion are welded to each other.
A power storage module having a plurality of protrusions on the peripheral edge of the electrode plate, and the protrusions have a shape that becomes thicker from the proximal end side toward the distal end side. The power storage module according to claim 1, wherein the chemical bond is a covalent bond or a hydrogen bond. The annular resin portion has a portion that projects outward from the peripheral edge portion of each electrode plate and is buried in the tubular portion when viewed from the stacking direction of the electrode laminate, and the buried portion has the portion. The power storage module according to claim 1 or 2, which is welded to each other with a tubular portion. The electrode laminate includes an electrode plate and a negative electrode provided on one surface of the electrode plate at the outermost side in the lamination direction, and is arranged so that the one surface is inside the electrode laminate. In addition, it is equipped with a negative electrode terminal electrode.
The sealant is
A negative electrode terminal annular resin portion provided along the peripheral edge of the electrode plate of the negative electrode terminal electrode, and a negative electrode terminal annular resin portion.
Further includes a negative electrode termination bonding resin layer provided between the peripheral edge portion of the electrode plate of the negative electrode termination electrode and the negative electrode termination annular resin portion.
The negative electrode terminal bonding resin layer is an acid-modified polyolefin resin layer.
The negative electrode terminal annular resin portion is made of a thermoplastic resin containing the negative electrode terminal bonding resin layer and a resin having compatibility with the tubular portion.
The tubular portion is made of a thermoplastic resin containing a resin having compatibility with the cyclic resin portion and the negative electrode terminal annular resin portion.
The negative electrode terminal annular resin portion and the tubular portion are welded to each other .
The negative electrode terminal cyclic resin portion and the negative electrode terminal bonding resin layer are welded to each other .
The negative electrode termination bond resin layer and the peripheral edge portion of the electrode plate of the negative electrode termination electrode are adhered to each other via a chemical bond.
Any one of claims 1 to 3 , wherein the peripheral edge portion of the electrode plate of the negative electrode terminal electrode has a plurality of protrusions, and the protrusions have a shape that becomes thicker from the proximal end side toward the distal end side. The power storage module described in the section. The power storage module according to claim 4 , wherein the negative electrode termination bond resin layer and the peripheral edge portion of the electrode of the negative electrode termination electrode are bonded via a covalent bond or a hydrogen bond. The method for manufacturing a power storage module according to any one of claims 1 to 5.
A step of applying a liquid resin that forms a chemical bond with the electrode plate to the peripheral portion of the electrode plate of the bipolar electrode to form the bonded resin layer.
A manufacturing method comprising a step of adhering the cyclic resin portion to the bonded resin layer.

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