JP7087955B2 - Manufacturing method of power storage module and power storage module - Google Patents

Description

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

Conventionally, as a power storage module, for example, as described in Patent Document 1, a plurality of bipolar electrodes in which a current collector is arranged between a positive electrode layer and a negative electrode layer are laminated to form a laminated body, and an outer edge portion of the laminated body is formed. A power storage module sealed by a sealing body is known. As a method for manufacturing this power storage module, an outer edge portion of the laminated body is arranged inside the mold, resin is injected from the gate of the mold into the inside of the mold, and a sealed body is resin-molded on the outer edge portion of the laminated body. Thereby, it is conceivable to manufacture a power storage module.

Japanese Patent No. 4370902

By the way, in the method of manufacturing a power storage module as described above, in resin molding, the resin may flow between the laminated bipolar electrodes and the laminated body may be turned over. Further, in the method for manufacturing a power storage module as described above, the resin injected into the mold from the gate may pop out in a rod shape without getting wet and spreading on the wall surface of the mold due to jetting. When the resin that has popped out of the gate in a rod shape due to jetting comes into contact with air, a solidified layer is rapidly formed on the surface of the resin. When such rod-shaped resins are curved inside the mold and overlap each other, small welds may occur between the overlapping rod-shaped resins. Such welding may reduce the bonding strength between the laminated body and the sealed body.

Therefore, an object of the present invention is to provide a method for manufacturing a power storage module and a power storage module capable of reducing the turning of the laminated body and improving the bonding strength between the laminated body and the sealed body.

The present invention is a method for manufacturing a power storage module configured by sealing the outer edge portion of a laminated body in which a plurality of bipolar electrodes are laminated with a sealing body, and the outer edge portion of the laminated body is arranged inside a mold. It includes an arrangement process and a molding process in which resin is injected from the gate of the mold into the inside of the mold to form a sealed body on the outer edge of the laminated body with resin. In the molding process, the resin is laminated from the gate to the inside of the mold. A method for manufacturing a power storage module that ejects resin from a gate into the mold so that the resin ejected along the stacking direction of the body first contacts the outer edge of the laminate on the outermost side in the stacking direction of the laminate. Is.

According to this configuration, in a method for manufacturing a power storage module in which the outer edge portion of a laminate in which a plurality of bipolar electrodes are laminated is sealed with a sealing body, the outer edge portion of the laminate is inside the mold in the placement process. Is arranged, resin is injected from the gate of the mold into the inside of the mold in the molding process, and the sealed body is resin-molded on the outer edge of the laminated body. In the molding process, the resin injected from the gate into the mold along the stacking direction of the laminate first contacts the outer edge of the laminate on the outermost side of the laminate direction from the gate to the mold. Since the resin is injected inside the gate, the resin injected from the gate presses the laminate in the stacking direction, and the resin flows between the laminated bipolar electrodes to reduce the possibility of the laminate being turned over. In addition, the resin immediately after being ejected from the gate along the stacking direction of the laminated body first hits the outer edge of the laminated body to suppress jetting and improve the bonding strength between the laminated body and the sealed body. Can be done.

In this case, in the arranging step, the outer edge portion of the laminate provided with the primary seal on each peripheral edge of the bipolar electrode is arranged inside the mold, and in the molding step, the bipolar electrode is viewed from the stacking direction of the laminate. It is preferable to inject the resin at a position where it overlaps with the primary seal.

According to this configuration, in the arranging step, the outer edge portion of the laminated body provided with the primary seal on each peripheral edge of the bipolar electrode is arranged inside the mold, and in the molding step, it is viewed from the laminating direction of the laminated body. Since the resin is injected at a position where the bipolar electrode and the primary seal overlap each other and have high strength, it is possible to reduce the damage of the primary seal due to the injection of the resin.

On the other hand, the present invention includes a laminated body in which a plurality of bipolar electrodes are laminated and a sealed body that seals an outer edge portion of the laminated body. The sealed body is formed by resin molding, and the laminated body is laminated. It is a power storage module having a gate mark due to a gate of a resin molding mold at a position where the outer edge portion of the laminated body and the sealing body overlap when viewed from the direction.

According to this configuration, in the power storage module provided with the laminated body in which a plurality of bipolar electrodes are laminated and the sealed body for sealing the outer edge portion of the laminated body, the sealed body is formed by resin molding. At the position where the outer edge of the laminated body and the sealed body overlap when viewed from the laminating direction of the laminated body, there is a gate mark by the gate of the resin molding mold, and in resin molding, the inside of the mold is from the gate. Since the resin ejected along the stacking direction of the laminated body first contacts the outer edge of the laminated body, the turning of the laminated body due to the resin flowing between the laminated bipolar electrodes is reduced. By suppressing jetting, the bonding strength between the laminated body and the sealed body is improved.

In this case, a primary seal is provided on each peripheral edge of the bipolar electrode of the laminated body, and the sealed body has a gate mark at a position where the bipolar electrode and the primary seal overlap when viewed from the stacking direction of the laminated body. It is preferable to have.

According to this configuration, a primary seal is provided on each peripheral edge of the bipolar electrode of the laminated body, and the sealed body is gated at a position where the bipolar electrode and the primary seal overlap when viewed from the stacking direction of the laminated body. In resin molding, the resin is injected at a position where the bipolar electrode and the primary seal overlap each other when viewed from the stacking direction of the laminated body. Damage is reduced, yield is improved, and it is cheaper.

According to the method for manufacturing a power storage module and the power storage module of the present invention, it is possible to reduce the turning of the laminated body and improve the bonding strength between the laminated body and the sealed body.

It is schematic cross-sectional view of the power storage device which used the power storage module which concerns on embodiment. FIG. 3 is a schematic cross-sectional view showing the internal configuration of the power storage module shown in FIG. 1. It is a figure which shows the arrangement process of the manufacturing method of the power storage module which concerns on embodiment. It is a figure which shows the molding process of the manufacturing method of the power storage module which concerns on embodiment. It is a figure which shows the state which the outer edge part of the laminated body is arranged inside the mold in the conventional manufacturing method of a power storage module. (A) is a diagram showing an ideal hot water flow in injection molding, and (B) shows a rod-shaped resin ejected from the gate into the mold without getting wet and spreading on the wall surface of the mold by jetting. The state is shown, and (C) is a figure which shows the state which the rod-shaped resin of (B) was curved inside the mold and overlapped with each other, and the small weld was generated between the overlapping rod-shaped resins. (A) and (B) are diagrams showing the flow of hot water by a conventional method for manufacturing a power storage module. (A), (B) and (C) are diagrams showing the flow of hot water according to the method for manufacturing a power storage module according to an embodiment.

FIG. 1 is a schematic cross-sectional view showing a power storage device including the power storage module according to the embodiment. 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 in which a plurality of power storage modules 4 are laminated with each other, and a restraint member 3 for applying 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 storage modules 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 adjacent to each other in the stacking direction and outside the power storage modules 4 located at the stacking ends. 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 in parallel with each other in a direction intersecting (orthogonal) with, for example, 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 to each other, but also serves as a heat sink that dissipates heat generated by the storage modules 4. It also has a function. 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 that sandwich the power storage module laminate 2 in the stacking direction, and fastening bolts 9 and nuts 10 that fasten the end plates 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 side 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 storage module stack 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 plate 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 shown in FIG. As shown in FIG. 2, the power storage module 4 is a secondary body that seals a laminated body 11 in which a plurality of bipolar electrodes 14 laminated in the stacking direction D1 are laminated and an outer edge portion 11p of the laminated body 11. It is provided with a seal (sealing body) 22.

The laminated body 11 includes a plurality of electrodes laminated in the stacking direction D1 via the separator 13. The plurality of electrodes include a plurality of bipolar electrodes 14, a negative electrode termination electrode 18, and a positive electrode termination electrode 19. In the present embodiment, the stacking direction D1 of the laminated body 11 coincides with the stacking direction of the power storage module laminated body 2. A primary seal 21a is provided on the peripheral edge of each of the bipolar electrodes 14 of the laminated body 11. A primary seal 21b is provided on the peripheral edge of the positive electrode terminal electrode 19. By integrating the primary seals 21a and 21b and the secondary seal 22, the laminate 11 and the secondary seal 22 are sealed.

The bipolar electrode 14 includes an electrode plate 15, a positive electrode active material layer 16 provided on one surface 15a of the electrode plate 15, and a negative electrode active material layer 17 provided on the other surface 15b of the electrode plate 15. The positive electrode active material layer 16 is formed by applying a positive electrode slurry containing a positive electrode active material. The negative electrode active material layer 17 is formed by applying a negative electrode slurry containing a negative electrode active material. In the laminated body 11, the positive electrode active material layer 16 of one bipolar electrode 14 faces the negative electrode active material layer 17 of one of the bipolar electrodes 14 adjacent to each other in the stacking direction D1 with the separator 13 interposed therebetween. In the laminated body 11, the negative electrode active material layer 17 of one bipolar electrode 14 faces the positive electrode active material layer 16 of the other bipolar electrode 14 adjacent to the stacking direction D1 with the separator 13 interposed therebetween.

In the laminated body 11, the negative electrode termination electrode 18 is arranged at one end of the stacking direction D1, and the positive electrode termination electrode 19 is arranged at the other end of the stacking direction D1. The negative electrode terminal electrode 18 includes an electrode plate 15 and a negative electrode active material layer 17 provided on the other surface 15b of the electrode plate 15. The negative electrode active material layer 17 of the negative electrode terminal electrode 18 faces the positive electrode active material layer 16 of the bipolar electrode 14 at one end in the stacking direction D1 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 active material layer 16 provided on one surface 15a of the electrode plate 15. The positive electrode active material layer 16 of the positive electrode terminal electrode 19 faces the negative electrode active material layer 17 of the bipolar electrode 14 at the other end of the stacking direction D1 via the separator 13. 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 electrode plate 15 is made of metal and is made of, for example, nickel or a nickel-plated steel plate. The electrode plate 15 is a rectangular metal leaf made of, for example, nickel. The peripheral edge portion 15c of the electrode plate 15 has a rectangular frame shape, and is an uncoated region in which the positive electrode active material and the negative electrode active material are not coated. A primary seal 21a is provided on each peripheral edge portion 15c of the electrode plate 15 of the bipolar electrode 14 of the laminated body 11. Further, a primary seal 21b is provided on the peripheral edge portion 15c of the electrode plate 15 of the positive electrode terminal electrode 19 of the laminated body 11.

Examples of the positive electrode active material constituting the positive electrode active material layer 16 include nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode active material layer 17 include a hydrogen storage alloy. In the present embodiment, the formation region of the negative electrode active material layer 17 on the other surface 15b of the electrode plate 15 is slightly larger than the formation region of the positive electrode active material layer 16 on the one side surface 15a of the electrode plate 15.

The separator 13 is formed, for example, in the form of a sheet. Examples of 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, methyl cellulose and the like, or a non-woven fabric. The separator 13 may be reinforced with a vinylidene fluoride resin compound. The separator 13 is not limited to a sheet shape, and a bag shape may be used.

The primary seals 21a and 21b and the secondary seal 22 are formed in a rectangular frame shape by, for example, an insulating resin. Examples of the resin material constituting the sealing member 12 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like. The primary seals 21a and 21b and the secondary seal 22 are configured to surround the laminated body 11 and directly and indirectly hold the peripheral edge portions 15c of the plurality of electrode plates 15.

As described above, the primary seals 21a and 21b are provided on the peripheral edge portion 15c of the electrode plate 15. The secondary seal 22 surrounds the primary seal 21 when viewed from the stacking direction D1. The primary seals 21a and 21b are films having a predetermined thickness (length in the stacking direction D1). The primary seals 21a and 21b have a rectangular frame shape when viewed from the stacking direction D1, and are continuously welded over the entire circumference of the peripheral edge portion 15c of the electrode plate 15 by, for example, ultrasonic waves or heat. The primary seals 21a and 21b are provided on the peripheral edge portion 15c on the other side surface 15b side of the electrode plate 15. The primary seals 21a and 21b are provided on the peripheral edge portion 15c and cover the end surface of the electrode plate 15. The primary seals 21a and 21b are provided apart from the positive electrode active material layer 16 and the negative electrode active material layer 17 when viewed from the stacking direction D1. The primary seals 21a and 21b adjacent to each other in the stacking direction D1 are in contact with each other. The outer edge portion of the separator 13 in contact with the negative electrode active material layer 17 of the electrode plate 15 is fixed to each of the primary seals 21a provided on the peripheral edge portion 15c of the electrode plate 15, for example, by welding.

The secondary seal 22 is provided on the outside of the laminated body 11 and the primary seal 21, and constitutes an outer wall (housing) of the power storage module 4. The secondary seal 22 is formed by resin molding such as injection molding of resin, as will be described later, and extends over the entire length of the laminated body 11 in the stacking direction D1. The secondary seal 22 is a tubular member extending in the stacking direction D1 in the axial direction. The secondary seal 22 covers the outer surface of the primary seal 21 extending in the stacking direction D1. The secondary seal 22 is joined to the outer surface of the primary seal 21 and seals the outer surface of the primary seal 21. The secondary seal 22 is welded to the outer surface of the primary seal 21 by, for example, heat during injection molding. The resin material constituting the primary seal 21 and the resin material constituting the secondary seal 22 are compatible with each other. The primary seal 21 is made of, for example, PP, and the secondary seal 22 is made of, for example, modified PPE.

The secondary seal 22 is formed by resin molding such as injection molding, and is resin-molded at a position where the outer edge portion 11p of the laminated body 11 and the secondary seal 22 overlap when viewed from the stacking direction D1 of the laminated body 11. It has a gate mark of 22 g due to the gate of the mold. Having a gate mark 22g at a position where the outer edge portion 11p of the laminated body 11 and the secondary seal 22 overlap when viewed from the stacking direction D1 of the laminated body 11 means that the gate is formed when viewed from the stacking direction D1 of the laminated body 11. It is included that not only the entire mark 22g but also a part of the gate mark 22g overlaps at the position where the outer edge portion 11p of the laminated body 11 and the secondary seal 22 overlap.

More specifically, in the secondary seal 22, the position where the bipolar electrode 14 and the primary seal 21a overlap and the positive electrode terminal electrode 19 and the primary seal 21b overlap when viewed from the stacking direction D1 of the laminated body 11. There is a gate mark 22g at the overlapping portion 11l, which is the position where the gate is located. When viewed from the stacking direction D1 of the laminated body 11, the gate mark 22g is located at the overlapping portion 11l where the bipolar electrode 14 and the primary seal 21a overlap and the positive electrode terminal electrode 19 and the primary seal 21b overlap. When viewed from the stacking direction D1 of the laminated body 11, not only the entire gate mark 22g but also a part of the gate mark 22g overlaps the bipolar electrode 14 and the primary seal 21a and the positive electrode terminal electrode. It includes overlapping the overlapping portion 11l, which is the position where 19 and the primary seal 21b overlap.

The gate mark 22g is generated by the gate of the resin molding mold when the secondary seal 22 is formed by resin molding. The gate mark 22g is, for example, a recess recessed from the surface of the secondary seal 22 in the overlapping portion 11l.

The electrode plate 15, the positive electrode active material layer 16, the negative electrode active material layer 17, and the primary seals 21a and 21b cooperate to form the internal space V between the electrode plates 15 adjacent to each other in the stacking direction D1. In other words, the space surrounded by the two electrode plates 15 adjacent to each other in the stacking direction D1, the positive electrode active material layer 16 of one electrode plate 15, the negative electrode active material layer 17 of the other electrode plate 15, and the primary seals 21a and 21b. Internal space V. Therefore, an internal space V exists between the bipolar electrodes 14 adjacent to each other in the stacking direction D1. Therefore, the laminated body 11 is provided with a plurality of internal spaces V. An alkaline electrolytic solution is injected into the internal space V including the inside of the separator 13. As the alkaline electrolytic solution, for example, an alkaline solution containing an aqueous solution of potassium hydroxide or the like is used. The primary seal 21a seals the internal space V.

Hereinafter, a method of manufacturing the power storage module of the present embodiment will be described. As shown in FIG. 3, in a method of manufacturing a power storage module 4 configured by sealing the outer edge portion 11p of a laminated body 11 in which a plurality of bipolar electrodes 14 are laminated with a secondary seal 22, the layers are laminated inside the mold 50. An arrangement step of arranging the outer edge portion 11p of the body 11 is performed. In the arranging step, the outer edge portion 11p of the laminated body 11 provided with the primary seal 21a on the peripheral edge portion 15c of each electrode plate 15 of the bipolar electrode 14 is arranged inside the mold 50.

In the arranging step, the outer edge portion 11p of the laminated body 11 is arranged inside the mold 50 so that the outer edge portion 11p of the laminated body 11 and the gate 51 overlap with each other when viewed from the stacking direction D1 of the laminated body 11. More specifically, in the arrangement step, the mold is formed so that the overlapping portion 11l and the gate 51, which are the positions where the bipolar electrode 14 and the primary seal 21a overlap, are overlapped with each other when viewed from the stacking direction D1 of the laminated body 11. The outer edge portion 11p of the laminated body 11 is arranged inside the 50.

As shown in FIG. 4, a molding step is performed in which the resin 52 is injected from the gate of the mold 50 into the inside of the mold 50 to resin-mold the secondary seal 22 on the outer edge portion 11p of the laminated body 11. In the molding step, the resin 52 injected from the gate 51 into the mold 50 along the stacking direction D1 of the laminated body 11 is first formed on the outermost edge portion 11p of the laminated body 11 on the outermost side of the laminated body 11 in the stacking direction D1. The resin 52 is injected into the inside of the mold 50 from the gate 51 of the mold 50 so as to come into contact with each other.

It is said that the resin 52 ejected from the gate 51 into the mold 50 along the stacking direction D1 of the laminated body 11 first contacts the outer edge portion 11p of the laminated body 11 on the outermost side of the stacking direction D1 of the laminated body 11. This includes contacting not only the entire resin 52 but also a part of the resin 52 with the outermost edge portion 11p of the laminate 11 in the stacking direction D1 of the laminate 11. Further, the resin 52 injected along the stacking direction D1 of the laminated body 11 is, for example, the resin 52 injected in the direction parallel to the stacking direction D1 of the laminated body 11, for example, the stacking direction D1 of the laminated body 11. Contains the resin 52 injected in a direction inclined within 45 ° from a direction parallel to. In addition to being ejected downward from the gate 51, the resin 52 may be ejected upward from the gate 51. Further, the resin 52 may be injected so as to first come into contact with the outer edge portion 11p of the laminated body 11 on the outermost side of both of the laminated body 11 in the stacking direction D1.

In the molding step, the resin 52 is injected into the overlapping portion 11l at the position where the bipolar electrode 14 and the primary seals 21a and 21b overlap when viewed from the stacking direction D1 of the laminated body 11. When the resin 52 is ejected to the overlapping portion 11l at the position where the bipolar electrode 14 and the primary seals 21a and 21b overlap when viewed from the stacking direction D1 of the laminated body 11, not only the entire resin 52 but also the resin 52 is ejected. A part of the above includes the resin 52 being injected into the overlapping portion 11l at the position where the bipolar electrode 14 and the primary seals 21a and 21b overlap when viewed from the stacking direction D1 of the laminated body 11.

In the present embodiment, in the manufacturing method of the power storage module 4 configured by sealing the outer edge portion 11p of the laminated body 11 in which a plurality of bipolar electrodes 14 are laminated with a secondary seal 22, the inside of the mold 50 is formed in the placement process. The outer edge portion 11p of the laminated body 11 is arranged, the resin 52 is injected from the gate 51 of the mold 50 into the inside of the mold 50 in the molding process, and the secondary seal 22 is resin-molded on the outer edge portion 11p of the laminated body 11. In the molding step, the resin 52 injected from the gate 51 into the mold 50 along the stacking direction D1 of the laminated body 11 is first formed on the outermost edge portion 11p of the laminated body 11 on the outermost side of the stacking direction D of the laminated body 11. Since the resin 52 is injected from the gate 51 of the mold 50 into the inside of the mold 50 so as to be in contact with each other, the laminated body 11 is pressed in the stacking direction D1 by the resin 52 ejected from the gate 51, and the laminated bipolar It is possible to reduce the possibility that the resin 52 flows between the electrodes 14 and the laminated body 11 is turned over. Further, the resin 52 immediately after being ejected from the gate 51 along the stacking direction D1 of the laminated body 11 first collides with the outer edge portion 11p of the laminated body 11 to suppress jetting, and the laminated body 11 and the secondary seal 22 are suppressed. The bonding strength with and can be improved.

As shown in FIG. 5, in the conventional method for manufacturing a power storage module, when viewed from the stacking direction D1 of the laminated body 11, the outer edge portion 11p of the laminated body 11 and the gate 51 are laminated inside the mold 50 so as not to overlap with each other. The outer edge portion 11p of the body 11 is arranged. The resin 52 ejected from the gate 51 into the mold 50 does not first contact the laminate 11, but first contacts the wall surface of the mold 50. In this case, as shown in FIG. 6A, since the mold 50 is warmed in the ideal hot water flow, the formation of the solidified layer on the surface of the resin 52 ejected from the gate 51 proceeds slowly. The resin 52 ejected from the gate 51 spreads in a fan shape while getting wet on the inner wall surface of the mold 50. With such an ideal flow of hot water, it is unlikely that the laminated body 11 will be turned over or the bonding strength between the laminated body 11 and the secondary seal 22 will be lowered.

However, jetting occurs when the molten resin 52 passes through a region where flow is restricted such as a nozzle, a runner, and a gate 51, and is extruded into a thick open region at high speed without contacting the wall surface of the mold 50. Occur. When jetting occurs, as shown in FIG. 6B, the resin 52 ejected from the gate 51 pops out in a rod shape without getting wet and spreading on the wall surface of the mold 50. When the resin 52 protruding from the gate 51 in a rod shape by jetting comes into contact with air, a solidified layer is rapidly formed on the surface of the resin 52. As shown in FIG. 6C, when such rod-shaped resins 52 are curved inside the mold 50 and overlap each other, small welds may be generated between the overlapping rod-shaped resins 52. Such welds cause a decrease in the bonding strength between the laminated body 11 and the secondary seal 22.

As shown in FIG. 7A, in the conventional method for manufacturing a power storage module, the resin 52 immediately after being ejected from the gate 51 does not diffuse until it hits the wall surface of the mold 50 by jetting, and is inside the mold 50. Inflow to. As shown in FIG. 7B, the resin 52 that has flowed into the mold 50 hits the wall surface of the mold 50 and then diffuses into a fan shape at the upper part of the mold 50. Since the resin 52 flows into the stacking direction D1 at once and then diffuses at the upper part of the mold 50, the resin 52 is located between the bipolar electrodes 14 of the laminated body 11 rather than the force for pressing the laminated body 11 in the stacking direction D1. The force of invasion is greater. As a result, the resin 52 gets into the space between the bipolar electrodes 14, and the resin 52 is turned over.

On the other hand, in the present embodiment, as shown in FIGS. 8 (A), 8 (B) and 8 (C), the resin 52 ejected from the gate 51 along the stacking direction D1 of the laminated body 11 is in the stacking direction. Since the outermost layer 11 of D is first contacted with the outer edge portion 11p, the resin 52 ejected from the gate 51 presses the laminate 11 in the stacking direction D1, and the resin 52 is sandwiched between the laminated bipolar electrodes 14. Is reduced from flowing in and turning over the laminated body 11. Further, the resin 52 immediately after being ejected from the gate 51 first hits the outer edge portion 11p of the laminated body 11 to suppress jetting, and the bonding strength between the laminated body 11 and the secondary seal 22 can be improved. ..

Further, in the present embodiment, in the arrangement step, the laminated body 11 is provided with the primary seals 21a and 21b on the peripheral edge portion 15c of each electrode plate 15 of the bipolar electrode 14 and the peripheral edge portion 15c of the electrode plate 15 of the positive electrode terminal electrode 19. The outer edge portion 11p of the above is arranged inside the mold 50, and in the molding process, the strength of the bipolar electrode 14, the positive electrode terminal electrode 19 and the primary seals 21a and 21b overlapping when viewed from the stacking direction D1 of the laminated body 11 is high. Since the resin 52 is injected into the overlapping portion 11l, which is a strong position, damage to the primary seal 21a due to the injection of the resin 52 can be reduced.

Further, in the present embodiment, in the power storage module 4 provided with the laminated body 11 in which a plurality of bipolar electrodes 14 are laminated and the secondary seal 22 for sealing the outer edge portion 11p of the laminated body 11, the secondary seal 22 is used. It is formed by resin molding, and is gated by the gate 51 of the resin molding mold 50 at a position where the outer edge portion 11p of the laminated body 11 and the secondary seal 22 overlap when viewed from the stacking direction D1 of the laminated body 11. In resin molding, the resin 52 injected from the gate 51 into the inside of the mold 50 along the stacking direction D1 of the laminated body 11 has a mark of 22 g and first contacts the outer edge portion 11p of the laminated body 11. Therefore, the turning of the laminated body 11 due to the inflow of the resin 52 between the laminated bipolar electrodes 14 is reduced, and the bonding strength between the laminated body 11 and the secondary seal 22 is improved by suppressing jetting. ..

Further, in the present embodiment, a primary seal 21a is provided on the peripheral edge portion 15c of each electrode plate 15 of the bipolar electrode 14 of the laminated body 11, and the secondary seal 22 is a bipolar electrode when viewed from the stacking direction D1 of the laminated body 11. A gate mark 22g is provided at the overlapping portion 11l where the 14 and the primary seal 21a overlap, and in resin molding, the bipolar electrode 14 and the primary seal 21a overlap when viewed from the stacking direction D1 of the laminated body 11. Since the resin 52 is injected into the overlapping portion 11l, which is a position where the strength is strong, damage to the primary seal 21a due to the injection of the resin 52 is reduced, the yield is improved, and the cost is reduced.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, the shapes of the primary seals 21a and 21b and the secondary seal 22 in the above-described embodiment are arbitrary and can be changed as appropriate. Further, in the above-described embodiment, the case where the power storage module 4 is used as the power storage device 1 in which the power storage modules 4 are stacked has been described as shown in FIG. 1, but the power storage module 4 may be used in a different structure or form. Further, in the above-described embodiment, the case where the power storage module 4 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles has been described, but it may be used for other purposes.

1 ... power storage device, 2 ... power storage module laminate, 3 ... restraint member, 4 ... power storage module, 5 ... conductive plate, 5a ... flow path, 6 ... positive electrode terminal, 7 ... negative electrode terminal, 8 ... end plate, 8a ... insertion Holes, 9 ... Fastening bolts, 10 ... Nuts, 11 ... Laminates, 11p ... Outer edges, 11l ... Overlapping parts, 13 ... Separator, 14 ... Bipolar electrodes (electrodes), 15 ... Electrode plates, 15a ... One side, 15b ... On the other side, 15c ... peripheral portion, 16 ... positive electrode active material layer, 17 ... negative electrode active material layer, 18 ... negative electrode terminal electrode, 19 ... positive electrode terminal electrode, 21a, 21b ... primary seal, 22 ... secondary seal (sealed body). ), 22 g ... Gate mark, 50 ... Mold, 51 ... Gate, 52 ... Resin, F ... Film, D1 ... Laminating direction, V ... Internal space.

Claims (4)

It is a method of manufacturing a power storage module configured by sealing the outer edge of a laminated body in which a plurality of bipolar electrodes are laminated with a sealing body.
An arrangement step of arranging the outer edge portion of the laminated body inside the mold, and
A molding step of injecting resin from the gate of the mold into the inside of the mold to resin-mold the sealed body on the outer edge portion of the laminated body.
Equipped with
In the arrangement step, the laminate is arranged inside the mold so that the outer edge portion of the laminate and the gate overlap when viewed from the stacking direction of the laminate.
In the molding step, the resin ejected from the gate into the inside of the mold along the stacking direction of the laminated body is first applied to the outer edge portion of the laminated body on the outermost side of the laminated body in the stacking direction. A method for manufacturing a power storage module, in which the resin is injected from the gate into the inside of the mold so as to be in contact with the mold. In the arrangement step, the outer edge portion of the laminate provided with the primary seal on each peripheral edge portion of the bipolar electrode is arranged inside the mold.
The method for manufacturing a power storage module according to claim 1, wherein in the molding step, the resin is injected at a position where the bipolar electrode and the primary seal overlap when viewed from the stacking direction of the laminated body. A laminated body in which multiple bipolar electrodes are laminated, and
A sealing body that seals the outer edge of the laminated body and
Equipped with
The sealed body is formed by resin molding, and the outer edge portion of the laminated body and the sealed body overlap with the outermost portion of the laminated body in the laminated direction when viewed from the stacking direction of the laminated body. A power storage module having a gate mark due to the gate of the resin molding mold at the position where the metal is formed. A primary seal is provided on each peripheral edge of the bipolar electrode of the laminate.
The power storage module according to claim 3, wherein the sealed body has the gate mark at a position where the bipolar electrode and the primary seal overlap when viewed from the stacking direction of the laminated body.

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