JP7102912B2 - 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 method for manufacturing a power storage module and a power storage module, for example, as described in Japanese Patent Application Laid-Open No. 2007-128792, a laminate in which a separator is arranged between a positive electrode and a negative electrode is produced, and the laminate is laminated. There is known a power storage module that is wrapped in a film and the periphery thereof is resin-molded and sealed.

Japanese Unexamined Patent Publication No. 2007-128792

Such a method for manufacturing a power storage module and a power storage module may cause molding defects during the manufacture of the power storage module. For example, when a sealing body is provided around a rectangular laminated body by resin molding, sink marks or voids may occur at the corners of the sealing body. More specifically, as shown in FIG. 13, when a sealed body is formed around the laminated body 101 by resin molding, the molten resin 103 flows in a large direction at the corners of the molded region 102 of the sealed body. Since it changes, shearing heat is generated between the flowing resin 103 and the mold 104. As a result, it is considered that the resin 103 locally becomes hot at the corners, and the amount of shrinkage becomes larger than that of other parts due to the subsequent cooling, resulting in poor molding of 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 appropriately manufacturing a power storage module by suppressing molding defects of a sealed body.

That is, in the method for manufacturing a power storage module according to the present invention, a plurality of bipolar electrodes are laminated to prepare a laminated body having a rectangular cross section orthogonal to the stacking direction, and a sealed body is placed on the outer edge of the laminated body when viewed from the stacking direction. In the method of manufacturing a power storage module provided and configured, a manufacturing step of laminating a plurality of bipolar electrodes to prepare a laminated body, an arranging step of arranging the laminated body having a notch formed inside a mold, and a gold Including a molding step of injecting resin into the mold and resin-molding the sealed body over the entire circumference of the outer edge of the laminate, in the manufacturing step, a notch portion having a shape in which the corners of the rectangle were cut off was formed. A laminate has been produced. According to this method of manufacturing a power storage module, notches are formed at the corners of the laminate, and the sealant is resin-molded on the outer edge of the laminate, so that the sealant is sealed when the sealant is resin-molded. The resin can flow smoothly at the corners of the molded area of the body. Therefore, molding defects can be suppressed at the corners of the sealed body, and the power storage module can be appropriately manufactured.

Further, in the method for manufacturing a power storage module according to the present invention, a rectangular frame-shaped outer edge resin portion continuously formed over the entire circumference is provided on the outer edge of the bipolar electrode, and the outer edge resin portion is provided in the manufacturing process. A laminated body may be produced in which an outer edge resin portion having a notch formed at a corner portion when viewed from the laminating direction is provided. In this case, since the notch portion is formed by cutting off the corner portion of the outer edge resin portion, the notch portion can be formed without notching the electrically functioning portion such as the electrode of the bipolar electrode.

Further, in the method for manufacturing a power storage module according to the present invention, in the manufacturing process, the outer edge resin portion is formed so as to project outward from the electrode plate of the bipolar electrode when viewed from the stacking direction, and the outer edge resin portion at the corner portion is formed to the outside. The notch portion may be formed so that the protruding width is the same as the outward protruding width of the outer edge resin portion other than the corner portion. In this case, a notch portion having a sufficient size can be formed, and when the encapsulant is resin-molded, the resin can be smoothly flowed at the corner portion of the molding region of the encapsulant. Therefore, molding defects can be suppressed at the corners of the sealed body, and the power storage module can be appropriately manufactured.

The power storage module according to the present invention is a power storage module configured by providing a sealing body on the outer edge of a laminated body having a rectangular cross section orthogonal to the stacking direction when a plurality of bipolar electrodes are stacked and viewed from the stacking direction. Is configured by forming a notch portion having a shape in which the corners of a rectangle are cut off. According to this power storage module, notches are formed at the corners of the laminated body, so that when the sealed body is resin-molded on the outer edge of the laminated body, the sealed body is formed when the sealed body is resin-molded. The resin can be smoothly flowed at the corners of the molding region. Therefore, molding defects can be suppressed at the corners of the sealed body, and the power storage module can be appropriately manufactured.

Further, in the power storage module according to the present invention, a rectangular frame-shaped outer edge resin portion formed continuously over the entire circumference is provided on the outer edge of the bipolar electrode, and the notch portion is viewed from the stacking direction of the outer edge resin portion. It may be formed at the corners. In this case, since the notch is formed at the corner of the outer edge resin portion, the notch can be formed without notching the electrically functioning portion such as the electrode of the bipolar electrode.

Further, in the power storage module according to the present invention, the outer edge resin portion is formed so as to project outward from the electrode plate of the bipolar electrode when viewed from the stacking direction, and the notch portion has a protruding width at the corner portion of the outer edge resin portion. It may be formed so as to have the same width as the protruding width other than the above. In this case, a notch portion having a sufficient size can be formed, and when the encapsulant is resin-molded, the resin can be smoothly flowed at the corner portion of the molding region of the encapsulant. Therefore, molding defects can be suppressed at the corners of the sealed body, and the power storage module can be appropriately manufactured.

According to the present invention, it is possible to appropriately manufacture a power storage module by suppressing molding defects in resin molding of a sealed body.

It is the schematic sectional drawing of the power storage device using the power storage module which concerns on embodiment of this invention. It is the schematic sectional drawing which shows the internal structure of the power storage module. It is a top view of the power storage module of FIG. It is a figure which shows an example of the cutout part of the electrode laminated body in the power storage module of FIG. It is a figure which shows the modification of the notch part of the electrode laminated body in the power storage module of FIG. It is a figure which shows the modification of the notch part of the electrode laminated body in the power storage module of FIG. It is a top view of the bipolar electrode shown in FIG. It is a top view of the negative electrode terminal electrode shown in FIG. It is a top view of the bipolar electrode and the negative electrode terminal electrode which were laminated with each other. It is a flowchart which shows each process of the manufacturing method of the power storage module which concerns on this embodiment. It is a process outline diagram of resin molding in the manufacturing method of the power storage module which concerns on this embodiment. It is explanatory drawing of the molding process in the manufacturing method of the power storage module which concerns on this embodiment. It is explanatory drawing of the background technique.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a schematic cross-sectional view of a power storage device 1 using the power storage module 4 according to the present embodiment. The power storage device 1 shown in FIG. 1 shows an example of a power storage device using the power storage module 4, and is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 is constrained to the module stack 2 including the plurality of stacked power storage modules 4 and the stacking direction of the module stack 2 (here, the electrode stacking direction D in the electrode stack 11 described later). It is provided with a restraint member 3 for applying a load.

The module laminate 2 includes a plurality of (three in this case) power storage modules 4 and a plurality of (four in this case) conductive plates 5. The power storage module 4 is a bipolar battery and has a rectangular shape when viewed from the stacking direction D. 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 D 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 D and outside the stacking direction D of 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 stacking direction D of the power storage module 4 located at the stacking end. The negative electrode terminal 7 is connected to the other conductive plate 5 arranged outside the stacking direction D of the power storage module 4 located at the stacking 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 the stacking direction D. The positive electrode terminal 6 and the negative electrode terminal 7 charge and discharge the power storage device 1.

Inside the conductive plate 5, a plurality of flow paths 5a for passing a refrigerant such as air are provided. The flow path 5a extends along a direction intersecting (orthogonal) with, for example, the stacking direction D and the drawing directions of the positive electrode terminal 6 and the negative electrode terminal 7. The conductive plate 5 not only functions as a connecting member that electrically connects the power storage modules 4 to each other, but also serves as a heat sink that dissipates heat generated by the power storage module 4 by circulating a refrigerant through these flow paths 5a. It also has a function. In the example of FIG. 1, the area of the conductive plate 5 seen from the stacking direction D 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 the area, or 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 module laminate 2 in the stacking direction D, 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 as viewed from the stacking direction D. A film F having electrical insulation is provided on the inner surface of the end plate 8 in the stacking direction D (the surface facing the module laminate 2 side). The film F insulates between the end plate 8 and the conductive plate 5.

The end plate 8 is provided with an insertion hole 8a at an edge portion on the outer peripheral side of the portion overlapping the module laminate 2 in the stacking direction D. 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 module laminate 2, and a restraining load is applied to the module laminate 2 in the stacking direction D.

Next, the configuration of the power storage module 4 will be described in detail. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module 4 shown in FIG. As shown in FIG. 2, the power storage module 4 has an electrode laminate (laminate) 11 formed by laminating a plurality of bipolar electrodes 14, and a resin sealing body 12 is provided on the outer edge of the electrode laminate 11. Is provided. The electrode laminate 11 has a plurality of electrodes (a plurality of bipolar electrodes 14, a single negative electrode terminal electrode 18, and a single electrode) laminated along the stacking direction D (first direction) via the separator 13 and the separator 13. One positive electrode termination electrode 19) is included. Here, the stacking direction D of the electrode laminated body 11 coincides with the stacking direction of the module laminated body 2. The electrode laminate 11 has a side surface 11b extending in the stacking direction D. As an example, the side surface 11b is configured as a set of end faces (planes connecting the first surface 15a and the second surface 15b) of the electrode plate 15 described later.

The bipolar electrode 14 includes an electrode plate 15, a positive electrode 16, and a negative electrode 17. The positive electrode 16 is provided on the first surface 15a of the electrode plate 15. The negative electrode 17 is provided on the second surface 15b opposite to the first surface 15a of the electrode plate 15. The electrode plate 15 is made of a metal such as nickel or a nickel-plated steel plate. As an example, the electrode plate 15 is a rectangular metal leaf made of nickel. The electrode plate 15 includes a rectangular outer edge 15d when viewed from the stacking direction D.

The positive electrode 16 is a positive electrode active material layer formed by applying the positive electrode active material to the electrode plate 15. Examples of the positive electrode active material constituting the positive electrode 16 include nickel hydroxide. The positive electrode 16 includes a rectangular outer edge 16d when viewed from the stacking direction D. The negative electrode 17 is a negative electrode active material layer formed by applying the negative electrode active material to the electrode plate 15. Examples of the negative electrode active material constituting the negative electrode 17 include a hydrogen storage alloy. The negative electrode 17 includes an outer edge 17d having a rectangular shape when viewed from the stacking direction D.

In the present embodiment, the formation region of the negative electrode 17 on the second surface 15b of the electrode plate 15 is larger than the formation region of the positive electrode 16 on the first surface 15a of the electrode plate 15. That is, the outer edge 17d of the negative electrode 17 is one size larger than the outer edge 16d of the positive electrode 16. 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. That is, the peripheral edge portion 15c of the electrode plate 15 is a portion of the electrode plate 15 other than the region where the positive electrode 16 and the negative electrode 17 are formed when viewed from the stacking direction D, and is a portion surrounding the positive electrode 16 and the negative electrode 17. .. The surfaces of the bipolar electrode 14, the negative electrode terminal electrode 18, and the positive electrode terminal electrode 19 include the first surface 15a and the second surface 15b of the peripheral edge portion 15c of the electrode plate 15, respectively.

In the electrode laminate 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of another 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 17 of one bipolar electrode 14 faces the positive electrode 16 of yet another bipolar electrode 14 adjacent to the stacking direction D with the separator 13 interposed therebetween.

The negative electrode terminal electrode 18 includes an electrode plate 15 and a negative electrode 17 provided on the second surface 15b of the electrode plate 15. The negative electrode terminal electrode 18 does not include the positive electrode 16. That is, the active material layer is not provided on the first surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18 (that is, the entire first surface 15a of the negative electrode terminal 18 is exposed). The negative electrode terminal electrode 18 is arranged at one end of the stacking direction D so that the second surface 15b faces the inside of the stacking direction D of the electrode laminated body 11 (center side with respect to the stacking direction D). 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.

The positive electrode terminal electrode 19 includes an electrode plate 15 and a positive electrode 16 provided on the first surface 15a of the electrode plate 15. The positive electrode terminal electrode 19 does not include the negative electrode 17. That is, the active material layer is not provided on the second surface 15b of the electrode plate 15 of the positive electrode terminal electrode 19 (that is, the entire second surface 15b of the positive electrode terminal 19 is exposed). The positive electrode terminal electrode 19 is arranged at the other end of the stacking direction D so that the first surface 15a faces the inside of the stacking direction D of the electrode laminated body 11. 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 conductive plate 5 is in contact with the first surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18. Further, the conductive plate 5 of the adjacent power storage module 4 is in contact with the second surface 15b of the electrode plate 15 of the positive electrode terminal electrode 19. The restraint load from the restraint member 3 is applied to the electrode laminate 11 from the negative electrode terminal electrode 18 and the positive electrode terminal electrode 19 via the conductive plate 5. That is, the conductive plate 5 is also a restraining member that applies a restraining load to the electrode laminated body 11 along the stacking direction D.

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 sealing body 12 is formed of, for example, an insulating resin. The sealing body 12 is provided along the side surface 11b of the electrode laminated body 11 so as to surround the peripheral edge portion 15c. The sealing body 12 holds the peripheral edge portion 15c. The bipolar electrode 14 is provided with an intermediate resin portion 23. The intermediate resin portion 23 is provided along the outer edge of the bipolar electrode 14, and is provided over the entire circumference of the bipolar electrode 14. The intermediate resin portion 23 is provided by being joined to the outer edge of the electrode plate 15. The end portion of the intermediate resin portion 23 is joined to the sealing body 12. That is, the bipolar electrode 14 is joined to the sealing body 12 via the intermediate resin portion 23 and is supported by the sealing body 12. The intermediate resin portion 23 has a first intermediate resin portion 231 and a second intermediate resin portion 232. Details of the first intermediate resin portion 231 and the second intermediate resin portion 232 will be described later.

FIG. 3 is a plan view of the power storage module 4 when viewed from the stacking direction D. FIG. 4 is an explanatory view of the notch portion 11a. 5 and 6 are explanatory views of a modified example of the notch portion 11a. FIG. 7 is a diagram showing a bipolar electrode 14 to which the intermediate resin portion 23 is welded when viewed from the stacking direction D. FIG. 8 is a diagram showing a negative electrode terminal electrode 18 to which the negative electrode terminal resin portion 24 is welded when viewed from the stacking direction D. FIG. 9 is a diagram showing a bipolar electrode 14 and a negative electrode terminal electrode 18 when viewed from the stacking direction D. In the bipolar electrode 14 and the negative electrode terminal electrode 18 shown in FIG. 9, the intermediate resin portion 23 and the negative electrode terminal resin portion 24 are welded to each other and are laminated with each other.

In FIG. 3, the power storage module 4 is configured by providing a sealing body 12 on the outer edge of the rectangular electrode laminate 11. The electrode laminate 11 is provided by laminating a plurality of bipolar electrodes 14, and has a rectangular cross section in a direction orthogonal to the stacking direction of the bipolar electrodes 14. The sealing body 12 is continuously provided on the outer edge of the electrode laminated body 11 over the entire circumference. That is, the sealing body 12 is continuously provided on the outer edge of the electrode laminated body 11 when the electrode laminated body 11 is viewed from the laminating direction over the entire circumference. Notches 11a are formed at each of the four corners of the electrode laminate 11. The notch portion 11a is formed in a shape in which the corners of the rectangular electrode laminate 11 are cut off. That is, the notch portion 11a is formed in a shape in which the corners of the rectangular electrode laminate 11 are cut off diagonally. In other words, the notch portion 11a has a shape in which the corners of the rectangular electrode laminate 11 are chamfered, and functions as a chamfered portion. By forming such a notch portion 11a, the corner portion of the electrode laminate 11 is smoothly curved. Therefore, when the sealing body 12 is resin-molded, the resin flows smoothly at the corners of the molding region of the sealing body 12. Therefore, it is possible to suppress the occurrence of molding defects in the sealing body 12.

The notch portion 11a is cut off at least to the extent that the resin flows smoothly during resin molding of the sealing body 12. For example, in the notch portion 11a, the width of the primary sealing member protruding outward from the electrode plate 15 at the corner portion is the same as the width of the primary sealing member protruding outward from the electrode plate 15 in the region other than the corner portion. Is formed in. The primary seal member referred to here is an outer edge resin portion provided on the outer edge of the bipolar electrode 14, and corresponds to, for example, an intermediate resin portion 23, a negative electrode termination resin portion 24, and positive electrode termination resin portions 25 and 26. Specifically, as shown in FIG. 4, the intermediate resin portion 23 is formed to be larger than the electrode plate 15 and to protrude outward from the electrode plate 15. The notch portion 11a is formed so that the protruding width w at the corner portion of the intermediate resin portion 23 is the same width as the protruding width w1 other than the corner portion. It should be noted that the same width referred to here includes almost the same width, and if the notch portion 11a is formed with a width sufficient for the resin to flow smoothly during resin molding of the sealing body 12, the range of the same width is substantially the same. It is said that.

In FIG. 3, the cutout portion 11a has a shape in which the corners are cut off diagonally along one straight line, but the cutout portion 11a has the corners of the electrode laminate 11 as shown in FIG. It may be a shape cut off along a plurality of straight lines (two straight lines in FIG. 5), or as shown in FIG. 6, a shape in which the corners of the electrode laminate 11 are cut off in a curved shape, that is, a round shape with rounded corners. May be good. Even in these cases, by forming the electrode laminate 11 so that the corners are smooth, it is possible to suppress the occurrence of molding defects in the sealing body 12.

In FIG. 7, the intermediate resin portion 23 is a film having a predetermined thickness (length in the stacking direction D). The intermediate resin portion 23 has a rectangular frame shape when viewed from the stacking direction D, and is continuously provided over the entire circumference of the peripheral edge portion 15c of the bipolar electrode 14 as described above. The intermediate resin portion 23 includes a rectangular inner edge 23c and a rectangular outer edge 23d when viewed from the stacking direction D. The intermediate resin portion 23 is welded to the surface of the bipolar electrode 14 at least at the peripheral edge portion 15c of the bipolar electrode 14. Specifically, the intermediate resin portion 23 is welded to the first surface 15a of the bipolar electrode 14 and airtightly (liquid-tightly) bonded to the bipolar electrode 14.

A notch portion 11a is formed in the corner portion 23f of the intermediate resin portion 23. That is, notch portions 11a are formed in each of the four corner portions 23f of the intermediate resin portion 23 having a rectangular frame shape. The intermediate resin portion 23 functions as an outer edge resin portion provided on the outer edge of the bipolar electrode 14. Since the intermediate resin portion 23 is provided on the outer edge of the bipolar electrode 14 in a rectangular frame shape and the bipolar electrode 14 forms a part of the electrode laminate 11, the notch portion 11a in FIG. 7 is a notch of the electrode laminate 11. It functions as a part 11a.

As shown in FIG. 2, the intermediate resin portion 23 has a first intermediate resin portion 231 and a second intermediate resin portion 232. The first intermediate resin portion 231 and the second intermediate resin portion 232 are laminated with each other along the stacking direction D. Each of the first intermediate resin portion 231 and the second intermediate resin portion 232 has a rectangular frame shape when viewed from the stacking direction D, and includes a rectangular inner edge and an outer edge. When viewed from the stacking direction D, the outer edge of the first intermediate resin portion 231 and the outer edge of the second intermediate resin portion 232 coincide with each other and form the outer edge 23d of the intermediate resin portion 23.

Seen from the stacking direction D, the inner edge of the second intermediate resin portion 232 has a rectangular shape larger than the inner edge of the first intermediate resin portion 231. As a result, the step portion 23e is formed in the intermediate resin portion 23. The edge portion of the separator 13 is placed on the step portion 23e. The inner edge of the first intermediate resin portion 231 constitutes the inner edge 23c of the intermediate resin portion 23. The first intermediate resin portion 231 is welded to the first surface 15a of the bipolar electrode 14 and bonded to the electrode plate 15. The second intermediate resin portion 232 is welded onto the first intermediate resin portion 231 and bonded to the first intermediate resin portion 231.

In FIG. 8, the negative electrode terminal resin portion 24 is a film having a predetermined thickness (length in the stacking direction D). The negative electrode terminal resin portion 24 has a rectangular frame shape when viewed from the stacking direction D, and is continuously provided over the entire circumference of the peripheral edge portion 15c of the negative electrode terminal electrode 18. The negative electrode terminal resin portion 24 includes a rectangular inner edge 24c and a rectangular outer edge 24d when viewed from the stacking direction D. The negative electrode termination resin portion 24 is welded to the surface of the negative electrode termination electrode 18 at least at the peripheral edge portion 15c of the negative electrode termination electrode 18. Specifically, the negative electrode terminal resin portion 24 is welded to the first surface 15a of the negative electrode terminal electrode 18 and airtightly (liquid-tightly) bonded to the negative electrode terminal electrode 18.

A notch portion 11a is formed at the corner portion 24f of the negative electrode terminal resin portion 24. That is, notch portions 11a are formed in each of the four corner portions 24f of the negative electrode terminal resin portion 24 having a rectangular frame. The negative electrode terminal resin portion 24 functions as an outer edge resin portion provided on the outer edge of the bipolar electrode 14. Since the negative electrode terminal resin portion 24 is provided on the outer edge of the bipolar electrode 14 in a rectangular frame shape and the bipolar electrode 14 forms a part of the electrode laminate 11, the notch portion 11a in FIG. 8 is a cutout of the electrode laminate 11. It functions as a notch portion 11a.

In FIG. 2, the positive electrode terminal resin portions 25 and 26 are films having a predetermined thickness (length in the stacking direction D). The positive electrode termination resin portions 25 and 26 have a rectangular frame shape when viewed from the stacking direction D, and are continuously provided over the entire circumference of the peripheral edge portion 15c of the positive electrode termination electrode 19. The positive electrode terminal resin portion 25 includes a rectangular inner edge 25c and a rectangular outer edge 25d when viewed from the stacking direction D. The positive electrode terminal resin portion 25 is welded to the surface of the positive electrode terminal electrode 19 at least at the peripheral edge portion 15c of the positive electrode terminal electrode 19. Specifically, the positive electrode terminal resin portion 25 is welded to the first surface 15a of the positive electrode terminal electrode 19 and airtightly (liquid-tightly) bonded to the positive electrode terminal electrode 19.

Notches 11a are formed in the corners 25f and 26f of the positive electrode terminal resin portions 25 and 26, similarly to the negative electrode terminal resin portions 24 (see FIGS. 7 and 8). The positive electrode terminal resin portions 25 and 26 function as outer edge resin portions provided on the outer edge of the bipolar electrode 14. The positive electrode termination resin portions 25 and 26 are provided in a rectangular frame shape on the outer edge of the bipolar electrode 14, and the bipolar electrode 14 forms a part of the electrode laminate 11, so that the notches formed in the positive electrode termination resin portions 25 and 26 are formed. The portion 11a functions as a notch portion 11a of the electrode laminate 11. Although the case where the notch portions 11a are formed in all the corner portions of the intermediate resin portion 23, the negative electrode termination resin portion 24, and the positive electrode termination resin portions 25 and 26 has been described, the notch portions are partially formed in these corner portions. 11a may be formed. Even in this case, the above-mentioned action and effect can be obtained at the corner portion where the notch portion 11a is formed. That is, the resin can be smoothly flowed at the corners of the molding region of the sealing body 12, and the occurrence of molding defects of the sealing body 12 can be suppressed.

The positive electrode terminal resin portion 25 has a first portion 251 and a second portion 252. The first portion 251 and the second portion 252 are laminated with each other along the stacking direction D. Each of the first portion 251 and the second portion 252 has a rectangular frame shape when viewed from the stacking direction D, and includes a rectangular inner edge and an outer edge, respectively. Seen from the stacking direction D, the outer edge of the first portion 251 and the outer edge of the second portion 252 coincide with each other and form the outer edge 25d of the positive electrode terminal resin portion 25. Seen from the stacking direction D, the inner edge of the second portion 252 has a rectangular shape that is one size larger than the inner edge of the first portion 251. As a result, a stepped portion 25e is formed in the positive electrode terminal resin portion 25. The edge portion of the separator 13 is placed on the step portion 25e. The inner edge of the first portion 251 constitutes the inner edge 25c of the positive electrode terminal resin portion 25. The first portion 251 is welded to the first surface 15a of the positive electrode terminal electrode 19 and bonded to the electrode plate 15. The second portion 252 is welded onto the first portion 251 and joined to the first portion 251.

The positive electrode terminal resin portion 26 includes a rectangular inner edge 26c and a rectangular outer edge 26d when viewed from the stacking direction D. The positive electrode termination resin portion 26 is welded to the surface of the positive electrode termination electrode 19 at least at the peripheral edge portion 15c of the positive electrode termination electrode 19. Specifically, the positive electrode terminal resin portion 26 is welded to the second surface 15b of the positive electrode terminal electrode 19 and airtightly (liquid-tightly) bonded to the positive electrode terminal electrode 19.

Each of the intermediate resin portion 23, the negative electrode termination resin portion 24, and the positive electrode termination resin portion 25 is welded to the first surface 15a by, for example, ultrasonic waves or heat. The end face of the electrode plate 15 is not covered by the intermediate resin portion 23, the negative electrode termination resin portion 24, and the positive electrode termination resin portion 25, and is exposed. The inner end portions of the intermediate resin portion 23, the negative electrode termination resin portion 24, and the positive electrode termination resin portion 25 are located between the peripheral edges 15c of the electrode plates 15 adjacent to each other in the stacking direction D, and are the outer ends. The portion projects outward from the electrode plate 15 when viewed from the stacking direction D. Each of the intermediate resin portion 23, the negative electrode termination resin portion 24, and the positive electrode termination resin portion 25 is embedded in the second resin portion 22 at the outer end portion. The first resin portions 21 adjacent to each other along the stacking direction D are separated from each other.

The encapsulant 12 is formed between the bipolar electrodes 14 adjacent to each other along the stacking direction D, between the negative electrode termination electrodes 18 and the bipolar electrodes 14 adjacent to each other along the stacking direction D, and along the stacking direction D. The positive electrode terminal 19 and the bipolar electrode 14 adjacent to each other are sealed from each other. As a result, the internal space V is airtightly (liquid-tight) between the bipolar electrode 14, the negative electrode terminal 18 and the bipolar electrode 14, and the positive electrode terminal 19 and the bipolar electrode 14, respectively. Is formed. The internal space V contains an electrolytic solution (not shown) composed of an alkaline aqueous solution such as an aqueous potassium hydroxide solution. That is, the first resin portion 21 is for forming an internal space V in which the electrolytic solution is housed between adjacent electrodes along the stacking direction D and for sealing the internal space V. The electrolytic solution is impregnated in the separator 13, the positive electrode 16 and the negative electrode 17.

The sealant 12 is, for example, an insulating resin and may be composed of polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), or the like.

Next, the relative relationship of each part will be described in detail. The inside means the center side of the power storage module 4 when viewed from the stacking direction D. The outside means a side away from the center of the power storage module 4 when viewed from the stacking direction D. As shown in FIGS. 2 and 7, in the bipolar electrode 14, the negative electrode 17 is one size smaller than the electrode plate 15. That is, the outer edge 17d of the negative electrode 17 is located inside the outer edge 15d of the electrode plate 15. The positive electrode 16 is one size smaller than the negative electrode 17. That is, the outer edge 16d of the positive electrode 16 is located inside the outer edge 17d of the negative electrode 17. The outer edge 23d of the intermediate resin portion 23 is located outside the outer edge 15d of the electrode plate 15. The inner edge 23c of the intermediate resin portion 23 is located between the outer edge 15d of the electrode plate 15 and the outer edge 17d of the negative electrode 17.

The intermediate resin portion 23 is welded to the surface of the bipolar electrode 14 (here, the first surface 15a of the bipolar electrode 14) in the first area 15e (the region hatched in FIG. 7). In other words, the first area 15e is an area in which the intermediate resin portion 23 on the first surface 15a of the bipolar electrode 14 is welded, and has a rectangular frame shape due to the outer edge 15d of the electrode plate 15 and the inner edge 23c of the intermediate resin portion 23. It is an area specified in.

In the negative electrode terminal electrode 18, the negative electrode 17 is one size smaller than the electrode plate 15. That is, the outer edge 17d of the negative electrode 17 is located inside the outer edge 15d of the electrode plate 15. The positive electrode 16 is one size smaller than the negative electrode 17. That is, the outer edge 16d of the positive electrode 16 is located inside the outer edge 17d of the negative electrode 17. The outer edge 24d of the negative electrode terminal resin portion 24 is located outside the outer edge 15d of the electrode plate 15. The inner edge 24c of the negative electrode terminal resin portion 24 is located inside the outer edge 16d of the positive electrode 16. That is, the negative electrode terminal resin portion 24 extends so as to overlap the positive electrode 16.

The negative electrode terminal resin portion 24 is welded to the surface of the negative electrode terminal electrode 18 (here, the first surface 15a of the negative electrode terminal 18) in the second area 15f (the region hatched in FIG. 8). In other words, the second area 15f is an area where the negative electrode termination resin portion 24 on the first surface 15a of the negative electrode termination electrode 18 is welded, and is formed by the outer edge 15d of the electrode plate 15 and the inner edge 24c of the negative electrode termination resin portion 24. It is an area defined in a rectangular frame shape.

The outer edges 15d of the electrode plates 15 of the bipolar electrode 14 and the negative electrode terminal electrode 18 coincide with each other. The outer edges 17d of the negative electrodes 17 of the bipolar electrode 14 and the negative electrode terminal electrode 18 are aligned with each other. The outer edge 23d of the intermediate resin portion 23 and the outer edge 24d of the negative electrode terminal resin portion 24 coincide with each other. The inner edge 24c of the negative electrode terminal resin portion 24 is located inside the inner edge 23c of the intermediate resin portion 23. That is, the second area 15f is larger than the first area 15e. That is, in all the cross sections along the stacking direction D, the length of the second area 15f (width of the rectangular frame) is larger than the length of the first area 15e (width of the rectangular frame) (see FIG. 2). ). That is, the distance between the outer edge 15d of the electrode plate 15 of the negative electrode terminal electrode 18 and the inner edge 24c of the negative electrode terminal resin portion 24 is the distance between the outer edge 15d of the negative electrode terminal electrode 18 and the inner edge 24c of the negative electrode terminal resin portion 24 over the entire circumference of the electrode laminated body 11 when viewed from the stacking direction D. It is larger than the distance between the outer edge 15d of 15 and the inner edge 23c of the intermediate resin portion 23.

The positive electrode terminal resin portion 25 is welded to the surface of the positive electrode terminal electrode 19 (here, the first surface 15a of the positive electrode terminal 19) in the first area 15 g. In other words, the first area 15g is an area where the positive electrode termination resin portion 25 on the first surface 15a of the positive electrode termination electrode 19 is welded, and is formed by the outer edge 15d of the electrode plate 15 and the inner edge 25c of the positive electrode termination resin portion 25. It is an area defined in a rectangular frame shape. The positive electrode terminating resin portion 26 is welded to the surface of the positive electrode terminating electrode 19 (here, the second surface 15b of the positive electrode terminating electrode 19) and bonded to the positive electrode terminating electrode 19.

Next, a method of manufacturing the power storage module 4 according to the present embodiment will be described.

FIG. 10 is a flowchart showing a manufacturing process of the power storage module 4. As shown in FIG. 9, as the production of the power storage module 4, the electrode laminate 11 is first produced (S10). The electrode laminate 11 is produced by laminating and laminating a plurality of bipolar electrodes 14. Further, in addition to the bipolar electrode 14, the negative electrode terminal electrode 18 and the positive electrode terminal electrode 19 are laminated on the electrode laminated body 11. An intermediate resin portion 23 is attached to the bipolar electrode 14 in advance before being laminated. Further, the negative electrode terminal resin portion 24 is attached to the negative electrode terminal electrode 18 in advance before being laminated. Further, the positive electrode terminal resin portions 25 and 26 are attached to the positive electrode terminal electrode 19 in advance before being laminated.

At this time, in the intermediate resin portion 23, the negative electrode termination resin portion 24, and the positive electrode termination resin portions 25 and 26, a notch portion 11a is formed at a corner portion viewed from the stacking direction D. That is, the intermediate resin portion 23, the negative electrode terminal resin portion 24, and the positive electrode terminal resin portions 25, 26 in which the notch portion 11a is formed in advance are attached to the bipolar electrode 14, etc., and a plurality of the bipolar electrodes 14 and the like are laminated to form an electrode. The laminate 11 is produced. The intermediate resin portion 23, the negative electrode terminating resin portion 24, and the positive electrode terminating resin portions 25, 26 which do not form the notch portion 11a are attached to the bipolar electrode 14, etc., and after a plurality of the bipolar electrodes 14, etc. are laminated, the intermediate resin is used. The electrode laminate 11 may be produced by cutting off the corners of the portion 23, the negative electrode terminal resin portion 24, and the positive electrode terminal resin portions 25 and 26 to form the notch portion 11a.

Next, molding of the sealing body 12 is performed (S12). This molding step is a step of resin molding the sealing body 12 on the outer edge of the electrode laminate 11. For example, injection molding is performed using the electrode laminate 11 as an insert member, and the sealing body 12 is molded around the electrode laminate 11. Details of the molding process will be described later.

FIG. 11 is a schematic diagram of a resin molding process of the sealing body 12 in the manufacture of the power storage module 4. The power storage module 4 is manufactured by resin-molding the sealing body 12 on the outer edge of the electrode laminate 11. FIG. 11A is a diagram showing a process of arranging the electrode laminate 11. That is, the electrode laminate 11 is arranged in the mold 91 as an insert member. The electrode laminate 11 is configured by laminating a plurality of bipolar electrodes 14, and is manufactured in advance before resin molding. The mold 91 is a mold on the fixed side, and the electrode laminate 11 is arranged at a predetermined position of the mold 91.

11 (b) and 11 (c) are explanatory views of a molding process in which the sealing body 12 is resin-molded on the outer edge of the electrode laminated body 11. As shown in FIG. 11 (b), mold clamping is performed, and the mold 92 is joined to the mold 91. The mold 92 is a mold on the movable side, and can be approached and separated from the mold 91. A cavity 93 is formed inside the mold 91 and the mold 92. The cavity 93 is a molding region of the sealing body 12. That is, the sealing body 12 is formed by pouring the resin P into the hollow portion 93. The injection of the resin P into the cavity 93 is performed through the gate 94.

As shown in FIG. 12, the resin P flows along the hollow portion 93, which is the molding region of the sealing body 12. At this time, at the corner portion of the cavity portion 93, the region of the cavity portion 93 is bent at a right angle, but since the notch portion 11a is formed at the corner portion of the electrode laminate 11, the corner portion of the cavity portion 93 The curvature is small, and the resin P flows smoothly. That is, the radius of curvature at the corner of the cavity 93 is substantially large, the flow of the resin P is reduced from being stagnant at the corner, and the flow of the resin P becomes smooth. As a result, it is possible to suppress molding defects of the sealing body 12 at the corner portion 93a.

Then, as shown in FIG. 11 (c), when the entire cavity 93 is filled with the resin P, the resin P is cooled while applying pressure to the resin P for a predetermined time. As a result, the sealing body 12 is formed.

Then, the mold is opened to separate the mold 92 from the mold 91. After that, the resin-molded sealing body 12 on the outer edge of the electrode laminate 11 is taken out from the mold 91, and processing such as cutting off an unnecessary portion of the resin P is performed to complete the production of the power storage module 4.

As described above, according to the method of manufacturing the power storage module 4 and the power storage module 4 according to the present embodiment, the notch portion 11a is formed at the corner portion of the rectangular electrode laminate 11, and the outer edge of the electrode laminate 11 is formed. By resin-molding the sealing body 12, the resin P can be smoothly flowed at the corners of the molding region of the sealing body 12 when the sealing body 12 is resin-molded. Therefore, molding defects can be suppressed at the corners of the sealing body 12, and the power storage module can be appropriately manufactured.

Further, in the method of manufacturing the power storage module 4 and the power storage module 4 according to the present embodiment, a notch portion 11a having a shape in which the corners of the outer edge resin portion such as the intermediate resin portion 23 are cut off is formed. Therefore, the notch portion 11a can be formed without notching the electrically functioning portion such as the electrode of the bipolar electrode 14.

Further, in the method of manufacturing the power storage module 4 and the power storage module 4 according to the present embodiment, the outer edge resin portion such as the intermediate resin portion 23 is formed so as to project outward from the electrode plate 15 of the bipolar electrode 14, and the notch portion 11a is formed. The protrusion width w at the corner portion of the outer edge resin portion is formed to be the same width as the protrusion width w1 at the corner portion other than the corner portion. By forming the notch portion 11a having a sufficient size in this way, the resin P can be smoothly flowed at the corner portion of the molding region of the sealing body 12 when the sealing body 12 is resin-molded. .. Therefore, molding defects can be suppressed at the corners of the sealing body 12, and the power storage module 4 can be appropriately manufactured.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

For example, 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 a forklift, a hybrid vehicle, and an electric vehicle has been described, but it may be used for other purposes.

4 ... Power storage module, 11 ... Electrode laminated body (laminated body), 11a ... Notch, 12 ... Sealed body, 14 ... Bipolar electrode, 15 ... Electrode plate, 15a ... First surface, 15b ... Second surface, 15c ... Peripheral portion, 16 ... Positive electrode, 17 ... Negative electrode, 18 ... Negative electrode termination electrode, 23 ... Intermediate resin portion (outer edge resin portion), 24 ... Negative electrode termination resin portion (outer edge resin portion), 25 ... Positive electrode termination resin portion (outer edge resin) Part), 15e ... 1st area, 15f ... 2nd area, 23f, 24f, 25f and 26f ... corner, 91 ... mold, 92 ... mold, 93 ... cavity, 94 ... gate, D ... stacking direction, P ... resin, w ... protrusion width, w1 ... protrusion width.

Claims (4)

In a method for manufacturing a power storage module, which comprises stacking a plurality of bipolar electrodes to produce a laminated body having a rectangular cross section orthogonal to the stacking direction, and providing a sealing body on the outer edge of the laminated body as viewed from the stacking direction. ,
A manufacturing process for manufacturing the laminated body by laminating a plurality of bipolar electrodes, and
The arrangement step of arranging the laminated body inside the mold, and
A molding step of injecting a resin into the inside of the mold and resin-molding the sealed body over the entire outer edge of the laminated body is included.
In the manufacturing step, the laminated body in which the cutout portion having the shape of the rectangular corner is cut off is manufactured , and a rectangular frame-shaped outer edge is continuously formed on the outer edge of the bipolar electrode over the entire circumference. A resin portion is provided, and the notch portion is formed at a corner portion of the outer edge resin portion when viewed from the stacking direction.
Manufacturing method of power storage module. In the manufacturing step, the outer edge resin portion is formed so as to project outward from the electrode plate of the bipolar electrode when viewed from the stacking direction, and the protrusion width of the outer edge resin portion to the outside at the corner portion is other than the corner portion. The notch is formed so as to have the same width as the outward protrusion width of the outer edge resin portion in the above.
The method for manufacturing a power storage module according to claim 1 . In a power storage module configured by providing a sealing body on the outer edge of a laminated body having a rectangular cross section orthogonal to the stacking direction in which a plurality of bipolar electrodes are laminated when viewed from the stacking direction.
In the laminated body, a notch portion having a shape in which the corner of the rectangle is cut off is formed.
The outer edge of the bipolar electrode is provided with a rectangular frame-shaped outer edge resin portion that is continuously formed over the entire circumference.
The notch portion is formed at a corner portion of the outer edge resin portion as viewed from the stacking direction.
Power storage module. The outer edge resin portion is formed so as to project outward from the electrode plate of the bipolar electrode when viewed from the stacking direction.
The notch portion is formed so that the protruding width at the corner portion of the outer edge resin portion is the same as the protruding width other than the corner portion.
The power storage module according to claim 3 .

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