JP7103033B2 - Power storage module and manufacturing method of power storage module - Google Patents

Description

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

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 (see Patent Document 1). The bipolar battery includes a laminate formed by laminating a plurality of bipolar electrodes via a separator. On the side surface of the laminated body, a sealing body for sealing between the bipolar electrodes adjacent to each other in the stacking direction is provided, and the electrolytic solution is housed in the internal space formed between the bipolar electrodes.

Japanese Unexamined Patent Publication No. 2011-204386

In the battery as described above, a liquid injection port for injecting the electrolytic solution into the internal space is formed in the sealing body. After injecting the electrolyte, the injection port is sealed and the internal space is sealed. When gas is generated in the internal space with the use of the battery, the pressure in the internal space rises. In this case, the pressure tends to concentrate on the inner surface of the liquid injection port communicating with the internal space. If pressure is applied to the inner surface of the liquid injection port in the stacking direction, the liquid injection port may be deformed and the sealed body may be broken.

One aspect of the present invention is to provide a power storage module and a method for manufacturing a power storage module capable of suppressing deformation of a communication hole communicated with an internal space.

In the power storage module according to one aspect of the present invention, an electrode laminate including a plurality of electrodes laminated in the first direction and a communication hole communicating with an internal space provided between the plurality of adjacent electrodes are formed. The plurality of electrodes include a bipolar electrode, and the sealing member has a plurality of gate marks, and the plurality of adjacent electrodes are adjacent to each other when viewed from the first direction. The intermediate point of the gate mark is located so as not to overlap with the communication hole.

In this power storage module, when forming a seal member, resin materials flowing in from a plurality of adjacent gates collide with each other at an intermediate point between the plurality of adjacent gates. Therefore, in the obtained seal member, a fragile portion (weld portion) may be formed at an intermediate point between a plurality of adjacent gate marks. Even in such a case, when viewed from the first direction, the intermediate points of the plurality of adjacent gate marks are located so as not to overlap the communication holes, so that the seal member is located in the first direction from the communication holes. No fragile part is formed in the part located on the outside. Therefore, due to the increase in pressure in the internal space, even if pressure is applied to the inner surface of the communication hole in the first direction, deformation of the communication hole is suppressed.

A plurality of the communication holes are formed in the seal member, and the intermediate point may be located between the plurality of communication holes when viewed from the first direction. In this case, the intermediate points can be arranged so that the intermediate points do not overlap with the plurality of communication holes when viewed from the first direction.

The sealing member may have a surface on which a hole is formed, and the gate mark may be arranged in the hole. In this case, it is possible to prevent the protruding gate marks from protruding from the region of the surface of the sealing member where the holes are not formed.

The hole may be positioned so as not to overlap the communication hole when viewed from the first direction. In this case, since the hole portion is not formed in the portion of the seal member located outside the communication hole in the first direction, the thickness of the portion can be increased. Therefore, the deformation of the communication hole is further suppressed.

The method for manufacturing a power storage module according to one aspect of the present invention is an electrode laminate including a plurality of electrodes laminated in the first direction, and the plurality of electrodes are adjacent to the electrode laminate including a bipolar electrode. A method for manufacturing a power storage module including an internal space provided between a plurality of electrodes and a resin sealing member having a communication hole formed therein, wherein the electrode laminate is formed in a mold having a plurality of gates. In the step of forming the seal member, the step of forming the seal member by injection molding by pouring the resin material into the mold from the plurality of gates includes the step of arranging the seal member. The intermediate points of the plurality of adjacent gates are located so as not to overlap with the communication holes.

In this method of manufacturing a power storage module, resin materials flowing in from a plurality of adjacent gates collide with each other at an intermediate point between the plurality of adjacent gates. Therefore, in the obtained seal member, a fragile portion (weld portion) may be formed at the intermediate point. Even in such a case, when viewed from the first direction, the intermediate points of the plurality of adjacent gates are located so as not to overlap the communication holes, so that the seal member is located in the first direction as compared with the communication holes. No fragile part is formed in the part located on the outside. Therefore, due to the increase in pressure in the internal space, even if pressure is applied to the inner surface of the communication hole in the first direction, deformation of the communication hole is suppressed.

According to one aspect of the present invention, it is possible to provide a power storage module and a method for manufacturing a power storage module capable of suppressing deformation of a communication hole communicated with the internal space.

It is schematic cross-sectional view which shows the power storage device which includes the power storage module which concerns on one Embodiment. It is the schematic sectional drawing which shows the internal structure of the power storage module shown in FIG. It is a perspective view of the power storage module shown in FIG. It is a partial exploded perspective view of the power storage module shown in FIG. It is a partial cross-sectional view of the power storage module shown in FIG. It is a partial plan view of the power storage module shown in FIG. FIG. 6 is a cross-sectional view taken along the line VII-VII shown in FIG. It is a partial plan view of the mold in the step of arranging the electrode laminated body in the manufacturing method of the power storage module which concerns on one Embodiment. It is sectional drawing along the IX-IX line shown in FIG. It is a partial plan view of the seal member and the electrode laminate in the step of forming a seal member in the manufacturing method of the power storage module which concerns on one Embodiment.

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 duplicate description is omitted.

FIG. 1 is a schematic cross-sectional view showing a power storage device including a power storage module according to an 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 formed by stacking a plurality of power storage modules 4 on each other, 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 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 parallel to 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 power storage modules 4 to each other, but also serves as a heat sink that dissipates heat generated by the power 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 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 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 the figure, the power storage module 4 includes an electrode laminate 11 and a resin sealing member 12 surrounding the electrode laminate 11. The electrode laminate 11 and the sealing member 12 are sealed.

The electrode laminate 11 includes a plurality of electrodes E laminated in the stacking direction D (first direction) via the separator 13. The plurality of electrodes E include a plurality of bipolar electrodes 14, a negative electrode termination electrode 18, and a positive electrode termination electrode 19. 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 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 coated with a positive electrode active material. The negative electrode 17 is a negative electrode active material layer coated with a negative electrode active material. 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 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 (peripheral portion of the bipolar electrode 14) 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. 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 present embodiment, the formation region of the negative electrode 17 on the other surface 15b of the electrode plate 15 is slightly larger than the formation region of the positive electrode 16 on the one surface 15a of the electrode plate 15.

The separator 13 is formed in a sheet shape, for example. Examples of the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric 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 seal member 12 is formed in a rectangular frame shape by, for example, an insulating resin. Examples of the resin material constituting the seal member 12 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like. The seal member 12 is configured to surround the electrode laminate 11 and hold peripheral portions 15c of the plurality of electrode plates 15.

The seal member 12 has a primary seal 21 provided on the peripheral edge portion 15c and a secondary seal 22 provided around the primary seal 21. The primary seal 21 is a film having a predetermined thickness (length in the stacking direction D). The primary seal 21 has a rectangular frame shape when viewed from the stacking direction D, and is continuously welded over the entire circumference of the peripheral edge portion 15c by, for example, ultrasonic waves or heat. The primary seal 21 is provided on the peripheral edge portion 15c on the other surface 15b side of the electrode plate 15. The primary seal 21 is provided on the peripheral edge portion 15c in a state where the peripheral edge portion 15c is embedded, and covers the end surface of the electrode plate 15. The primary seal 21 is provided apart from the positive electrode 16 and the negative electrode 17 when viewed from the stacking direction D. The primary seals 21 adjacent to each other in the stacking direction D are in contact with each other.

The primary seal 21 has a first portion 21a and a second portion 21b. The first portion 21a is provided on the other surface 15b and overlaps with the electrode plate 15 when viewed from the stacking direction D. The second portion 21b is integrally formed with the first portion 21a and is provided outside the electrode plate 15 when viewed from the stacking direction D. The thickness of the first portion 21a is thinner than the thickness of the second portion 21b and is equal to or greater than the thickness of the negative electrode 17. A stepped surface 21c extending in the stacking direction D is formed between the first portion 21a and the second portion 21b.

An outer edge portion of the separator 13 is arranged on the upper surface of the first portion 21a. Seen from the stacking direction D, the first portion 21a and the outer edge portion of the separator 13 overlap each other. The outer edge portion of the separator 13 is fixed to the upper surface of the first portion 21a at a plurality of locations arranged along the outer edge of the separator 13 by, for example, welding. The outer edge of the separator 13 may be in contact with the stepped surface 21c or may be separated from the stepped surface 21c. In the present embodiment, the height of the stepped surface 21c (the length in the stacking direction D) is equal to or greater than the sum of the thickness of the separator 13 and the thickness of the positive electrode 16.

The secondary seal 22 is provided on the outside of the electrode laminate 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 injection molding of a resin, as will be described later, and extends over the entire length of the electrode laminate 11 in the lamination direction D. The secondary seal 22 is a tubular portion extending with the stacking direction D as the axial direction. The secondary seal 22 covers the outer surface of the primary seal 21 extending in the stacking direction D. 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 secondary seal 22 may be welded to the outer surface of the primary seal 21 by hot plate welding. 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.

A plurality of internal spaces V are provided in the electrode laminate 11. Each internal space V is provided between a plurality of adjacent electrodes E. The internal space V is a space between the electrode plates 15 adjacent to each other in the stacking direction D, which is airtightly and watertightly partitioned by the electrode plates 15 and the sealing member 12. The internal space V contains an electrolytic solution (not shown) composed of an alkaline aqueous solution such as an aqueous potassium hydroxide solution. The electrolytic solution is impregnated in the separator 13, the positive electrode 16 and the negative electrode 17. Since the electrolytic solution is strongly alkaline, the sealing member 12 is made of a resin material having strong alkali resistance.

FIG. 3 is a perspective view of the power storage module shown in FIG. FIG. 4 is a partially exploded perspective view of the power storage module shown in FIG. FIG. 5 is a partial cross-sectional view of the power storage module shown in FIG. As shown in FIGS. 3 to 5, the power storage module 4 further includes a plurality of (here, four) base members 27 and a plurality of (here, the same number as the number of base members 27) pressure regulating valves 28. ing. The base member 27 may be integrated with the pressure regulating valve 28 or may be integrated with the secondary seal 22.

The seal member 12 is formed with a plurality of (here, four) mounting recesses 24 to which the plurality of pressure regulating valves 28 are mounted. The mounting recess 24 is formed in the secondary seal 22. The base member 27 and the pressure adjusting valve 28 are provided in each of the mounting recesses 24.

The seal member 12 is formed with a plurality of (24 in this case) communication holes 25 that are communicated with a plurality of (24 in this case) internal spaces V. In one example, six communication holes 25 are formed in each of the four mounting recesses 24. Each communication hole 25 functions as a liquid injection port for injecting the electrolytic solution into the internal space V, and also functions as a connection port for the pressure regulating valve 28 after the electrolytic solution is injected. That is, the communication hole 25 is sealed by the pressure regulating valve 28. The open end of the communication hole 25 is located in the mounting recess 24. The communication hole 25 is provided so as to penetrate the seal member 12. The cross section of the communication hole 25 has, for example, a rectangular shape.

A plurality of (six in this case) communication holes 29 are formed inside each of the base members 27. The base member 27 is provided in the mounting recess 24 so that each of the communication holes 29 communicates with the internal space V through the communication holes 25. Further, the pressure adjusting valve 28 is provided in each of the base members 27 so as to seal the communication hole 29 (and the internal space V).

The base member 27 includes a base end surface 27a which is one end surface in the direction from the seal member 12 toward the pressure regulating valve 28, and a tip end surface 27b which is the other end surface. The communication hole 29 is provided so as to penetrate from the base end surface 27a to the tip end surface 27b. A joining protrusion 30 is provided so as to project from the tip surface 27b of the base member 27.

The pressure regulating valve 28 has a case 31, a plurality of (six in this case) valve bodies 32, and a cover 33. The case 31 is made of a resin such as polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE) (eg, by injection molding). As shown in FIG. 5, the case 31 has a bottom wall portion 34 including a bottom surface 34a joined to the base member 27.

The bottom wall portion 34 of the case 31 is provided with a plurality of (six in this case) communication holes 35 penetrating from the bottom surface 34a toward the opening 31a of the case 31. These communication holes 35 communicate with the communication holes 29 of the base member 27, respectively. The communication hole 35 has a circular cross section. Two joining protrusions 36 formed so as to partition the communication holes 35 are projected from the bottom surface 34a of the case 31. The joining protrusion 36 has a shape and dimensions corresponding to the joining protrusion 30.

Further, as shown in FIGS. 4 and 5, the case 31 has an inner wall portion 37 forming a plurality of (six in this case) accommodating recesses 37a for accommodating the valve body 32. The inner wall portion 37 is integrated with the bottom wall portion 34. The accommodating recess 37a has a circular cross section. The accommodating recess 37a can communicate with the communication hole 35. The valve body 32 is accommodated in the accommodating recess 37a so as to close the communication hole 35. The valve body 32 is a columnar member formed of an elastic body such as rubber. The valve body 32 opens and closes the communication hole 35. A gap GP is provided between the side surface of the valve body 32 and the inner surface surface of the accommodating recess 37a.

The cover 33 is a plate-shaped member that closes the opening 31a of the case 31. The cover 33 is made of a resin such as polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE). The cover 33 is joined to the open end surface of the case 31 by welding. The cover 33 also functions as a pressing member that presses the plurality of valve bodies 32 against the bottom wall portion 34 of the case 31. A storage space S communicating with the storage recess 37a is provided between the inner wall portion 37 of the case 31 and the cover 33. Further, the cover 33 is provided with a plurality of (two in this case) exhaust ports 38. The exhaust port 38 communicates with the accommodation space S. The pressure regulating valve 28 is joined to the base member 27. Specifically, the joining protrusion 30 and the joining protrusion 36 are welded to each other in a state where the joining protrusion 30 of the base member 27 and the joining protrusion 36 of the case 31 are aligned with each other. ..

In such a pressure adjusting valve 28, the communication hole 35 of the case 31 communicates with the internal space V through the communication hole 29 and the communication hole 25. Therefore, when the pressure in the internal space V is lower than the set pressure, the communication hole 35 is maintained in a valve closed state closed by the valve body 32 (the internal space V is sealed). On the other hand, when the pressure in the internal space V rises to exceed the set pressure, the valve body 32 is elastically deformed so as to be separated from the bottom wall portion 34 of the case 31, and the communication hole 35 is released from the closed state. Become. As a result, the gas in the internal space V escapes to the accommodation space S through the gap GP between the side surface of the valve body 32 and the inner surface of the accommodation recess 37a.

FIG. 6 is a partial plan view of the power storage module shown in FIG. FIG. 6 shows a part of the power storage module 4 as seen from the stacking direction D. FIG. 7 is a cross-sectional view taken along the line VII-VII shown in FIG.

As shown in FIGS. 6 and 7, the seal member 12 has a plurality of gate marks 40 formed by injection molding. Each gate mark 40 is provided on the secondary seal 22. The plurality of gate marks 40 are arranged along the frame-shaped seal member 12 on the surface 12s of the seal member 12 intersecting the stacking direction D. Each gate mark 40 is provided, for example, between the four corners of the sealing member 12 which is rectangular when viewed from the stacking direction D and between the two adjacent corners. Seen from the stacking direction D, the intermediate points 40M of the plurality of adjacent gate marks 40 are located so as not to overlap with the communication holes 25. That is, when viewed from the stacking direction D, the intermediate point 40M of the plurality of adjacent gate marks 40 is located offset from the communication hole 25. The outer shape of each gate mark 40 is, for example, circular when viewed from the stacking direction D. The intermediate point 40M is an intermediate point of a line segment connecting the centers of a plurality of adjacent gate marks 40. In the present embodiment, the intermediate point 40M is located between the plurality of communication holes 25 (that is, the region where the communication holes 25 are not provided) when viewed from the stacking direction D. The intermediate point 40M is located, for example, between the regions of the seal member 12 where the base member 27 and the pressure regulating valve 28 are attached.

A plurality of hole portions 41 are formed on the surface 12s of the seal member 12, and each gate mark 40 is arranged in each hole portion 41. The hole 41 is, for example, a hole having a circular cross section recessed in the stacking direction D. The hole 41 is located so as not to overlap the communication hole 25 when viewed from the stacking direction D. The gate mark 40 is, for example, a conical protrusion protruding in the stacking direction D. The height D1 of the gate mark 40 can be set to be equal to or less than the depth D2 of the hole 41. The height D1 of the gate mark 40 is, for example, 0.5 mm to 1 mm.

As described above, in the power storage module 4, the intermediate point 40M of the plurality of adjacent gate marks 40 is located so as not to overlap with the communication hole 25 when viewed from the stacking direction D. When the seal member 12 is formed, as will be described later, the resin materials (resin materials constituting the secondary seal 22) that have flowed in from the plurality of adjacent gates G are at the intermediate point GM of the plurality of adjacent gates G. Collision (see FIGS. 8 to 10). Therefore, in the obtained seal member 12, a fragile portion (weld portion) may be formed at an intermediate point 40M of a plurality of adjacent gate marks 40. Even in such a case, when viewed from the stacking direction D, the intermediate point 40M of the plurality of adjacent gate marks 40 is located so as not to overlap the communication hole 25, so that the stacking direction D of the sealing members 12 No fragile portion is formed in the portion located outside the communication hole 25. Therefore, even if pressure is applied to the inner surface of the communication hole 25 in the stacking direction D due to the pressure increase in the internal space V, the deformation of the communication hole 25 is suppressed. Therefore, deformation of the portion of the seal member 12 located outside the communication hole 25 in the stacking direction D is also suppressed. Therefore, it is possible to prevent the secondary seal 22 from peeling from the primary seal 21 at the edge P (see FIG. 7) of the joint surface between the secondary seal 22 and the primary seal 21.

On the joint surface between the secondary seal 22 and the primary seal 21 (the surface including the edge P), when the secondary seal 22 is formed by injection molding, the heat of the resin material of the molten secondary seal 22 causes the secondary seal to be sealed. The resin material of 22 and the resin material of the primary seal 21 are melted and compatible with each other. As a result, the secondary seal 22 and the primary seal 21 are welded. When the temperature of the resin material of the molten secondary seal 22 is high, the compatibility state becomes good, so that the joint strength of the joint surface between the secondary seal 22 and the primary seal 21 becomes high. The molten resin material of the secondary seal 22 is gradually cooled as it flows from the gate G (corresponding to the gate mark 40) to the intermediate point GM (corresponding to the intermediate point 40M) (see FIGS. 8 to 10). .. Therefore, the temperature of the resin material of the molten secondary seal 22 decreases from the gate G toward the intermediate point GM. Therefore, the joint strength of the joint surface between the secondary seal 22 and the primary seal 21 closest to the intermediate point 40M when viewed from the stacking direction D is the joint surface between the secondary seal 22 and the primary seal 21 closest to the gate mark 40. It is smaller than the joint strength of. Therefore, usually, in the vicinity of the intermediate point 40M, the secondary seal 22 is more easily peeled from the primary seal 21 than in the vicinity of the gate mark 40. However, in the power storage module 4, peeling can be suppressed in the vicinity of the intermediate point 40M.

Further, when viewed from the stacking direction D, the intermediate point 40M of the plurality of adjacent gate marks 40 is located between the plurality of communication holes 25. Therefore, the intermediate point 40M can be arranged so that the intermediate point 40M does not overlap with the plurality of communication holes 25 when viewed from the stacking direction D.

The gate mark 40 is arranged in the hole 41. Therefore, it is possible to prevent the protruding gate mark 40 from protruding from the region of the surface 12s of the sealing member 12 where the hole 41 is not formed.

The hole 41 is located so as not to overlap the communication hole 25 when viewed from the stacking direction D. Therefore, since the hole 41 is not formed in the portion of the seal member 12 located outside the communication hole 25 in the stacking direction D, the thickness of the portion can be increased. Therefore, the deformation of the communication hole 25 is further suppressed.

Next, a method of manufacturing the power storage module 4 will be described. FIG. 8 is a partial plan view of the mold in the step of arranging the electrode laminate in the method of manufacturing the power storage module according to the embodiment. FIG. 8 shows a part of the mold M as seen from the stacking direction D. FIG. 9 is a cross-sectional view taken along the line IX-IX shown in FIG. FIG. 10 is a partial plan view of the seal member and the electrode laminate in the step of forming the seal member in the method for manufacturing the power storage module according to the embodiment. FIG. 10 shows a part of the seal member 12 and the electrode laminate 11 as viewed from the stacking direction D.

First, as shown in FIGS. 8 and 9, the electrode laminate 11 is arranged in the mold M having a plurality of gates G. The mold M is, for example, a mold. The electrode laminate 11 is provided with a primary seal 21 in advance. The shape of the void Mh in the mold M corresponds to the shape of the secondary seal 22. The shape of each gate G is, for example, a columnar shape extending in the stacking direction D. An annular protrusion Mp is provided around the open end of the gate G in the mold M, for example. The protrusion Mp forms a hole 41 in the secondary seal 22.

Next, as shown in FIG. 10, the seal member 12 is formed by injection molding by pouring a resin material into the mold M from a plurality of gates G. Here, when viewed from the stacking direction D, the intermediate points GM of the plurality of adjacent gates G are located so as not to overlap with the communication holes 25. The resin material that has flowed from each gate G into the void Mh of the mold M moves along the direction A. Since the moving speeds of the resin materials are usually the same, the resin materials flowing in from the plurality of adjacent gates G collide with each other at the intermediate point GM of the plurality of adjacent gates G. Therefore, the joint surface W including the intermediate point GM is the reaching end of the resin material that has flowed in from each gate G. The secondary seal 22 is formed by joining the resin materials to each other on the joint surface W. As a result, the seal member 12 is formed. The communication hole 25 formed in the seal member 12 can be manufactured by forming the secondary seal 22 using, for example, a metal member (nesting).

Subsequently, the electrolytic solution is injected into the internal space V through the communication hole 25, and the communication hole 25 is sealed by the base member 27 and the pressure regulating valve 28, whereby the power storage module 4 is manufactured.

In the method of manufacturing the power storage module 4, the resin materials flowing in from the plurality of adjacent gates G are joined at the joint surface W including the intermediate point GM of the plurality of adjacent gates G. The temperature of the resin material flowing in from the gate G gradually decreases as the distance from the gate G increases. Therefore, the temperature of the resin material on the joint surface W is the lowest. As a result, in the obtained seal member 12, a fragile portion (weld portion) may be formed at the intermediate point GM. Even in such a case, since the intermediate point GM of the plurality of adjacent gates G is located so as not to overlap the communication hole 25 when viewed from the stacking direction D, the sealing member 12 is located in the stacking direction D. A fragile portion is not formed in a portion located outside the communication hole 25. Therefore, even if pressure is applied to the inner surface of the communication hole 25 in the stacking direction D due to the pressure increase in the internal space V, the deformation of the communication hole 25 is suppressed.

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment.

For example, the power storage module 4 may include a single pressure regulating valve 28. In that case, the intermediate point 40M of the plurality of adjacent gate marks 40, as viewed from the stacking direction D, is located so as not to overlap the communication holes 25, but may not be located between the plurality of communication holes 25. ..

Further, the gate mark 40 does not have to be arranged in the hole 41. In this case, the gate mark 40 may protrude from the surface 12s of the sealing member 12.

Further, in the seal member 12, the primary seal 21 and the secondary seal 22 may be integrated.

4 ... Power storage module, 11 ... Electrode laminate, 12 ... Seal member, 12s ... Surface, 14 ... Bipolar electrode, 25 ... Communication hole, 40 ... Gate mark, 40M ... Midpoint, 41 ... Hole, E ... Electrode, G ... Gate, GM ... Midpoint, M ... Type, V ... Internal space.

Claims (5)

An electrode laminate containing a plurality of electrodes laminated in the first direction,
A resin sealing member having a communication hole formed between the plurality of adjacent electrodes and communicating with the internal space.
With
The plurality of electrodes include bipolar electrodes.
The seal member has a plurality of gate marks and has a plurality of gate marks.
When viewed from the first direction, the intermediate points of the plurality of adjacent gate marks are located so as not to overlap the communication holes .
A power storage module in which each of the plurality of gate marks is located so as not to overlap the communication hole when viewed from the first direction . A plurality of the communication holes are formed in the seal member.
The power storage module according to claim 1, wherein the intermediate point is located between the plurality of communication holes when viewed from the first direction. The sealing member has a surface on which a hole is formed, and the sealing member has a surface on which a hole is formed.
The power storage module according to claim 1 or 2, wherein the gate mark is arranged in the hole. The power storage module according to claim 3, wherein the hole is located so as not to overlap the communication hole when viewed from the first direction. It is an electrode laminate including a plurality of electrodes laminated in the first direction, and the plurality of electrodes are communicated with the electrode laminate including a bipolar electrode and an internal space provided between the plurality of adjacent electrodes. It is a method of manufacturing a power storage module including a resin sealing member having a communication hole formed therein.
A step of arranging the electrode laminate in a mold having a plurality of gates, and
A step of forming the seal member by injection molding by pouring a resin material into the mold from the plurality of gates.
Including
In the step of forming the seal member, the intermediate points of the plurality of adjacent gates are located so as not to overlap with the communication holes when viewed from the first direction, and the plurality of gates are located when viewed from the first direction. A method for manufacturing a power storage module, wherein each of the gates of the above gates is located so as not to overlap with the communication hole .

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