JP2020107412A - Electrode unit manufacturing method and electrode unit preparation body - Google Patents

Abstract

To provide an electrode unit manufacturing method capable of controlling productivity decline.SOLUTION: An electrode unit manufacturing method for manufacturing an electrode unit including an electrode plate, and a frame surrounding the marginal part of the electrode plate and joined thereto comprises a step of forming rectangular perforations 125 in a resin film 121, i.e., the base material of the frame, along the inner edge of the frame, a step of joining the marginal part of the electrode plate and the outside of the perforations 125 in the resin film 121 each other, and a step of removing the inside part 124 in the resin film 121 joined to the electrode plate surrounded by the perforations 125, from one end side toward the other end side, in the direction along any one of the long side and the short side forming a rectangle. In the step of forming the perforations 125, the perforations 125 are formed so that the force required for separating the perforations 125 on one end side is smaller than the force required for separating the perforations 125 on the other end side.SELECTED DRAWING: Figure 8

Description

One aspect of the present invention relates to an electrode unit manufacturing method and an electrode unit preparation body.

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

JP, 2005-190713, A

When manufacturing a bipolar battery as disclosed in Patent Document 1, for example, it is considered that an electrode unit in which a frame body serving as a seal layer is attached to an edge portion of an electrode plate (current collector) is manufactured in advance. To be When manufacturing the electrode unit, in order to attach the frame body to the edge portion of the electrode plate, it is necessary to join the frame body and the current collector to each other in a state where the frame body is superposed on the electrode plate. However, the frame body is generally easily distorted and is not easy to handle. Therefore, a great deal of time and labor may be required for the work of joining the frame body and the electrode plate, which may lead to a decrease in productivity.

An object of one aspect of the present invention is to provide an electrode unit manufacturing method capable of suppressing a decrease in productivity.

An electrode unit manufacturing method according to one aspect of the present invention is an electrode unit manufacturing method for manufacturing an electrode unit including an electrode plate and a frame body surrounding the edge of the electrode plate and joined to the edge, A step of forming a rectangular perforation along the inner edge of the frame in the resin film which is the base material of the frame, a step of joining the edge portion of the electrode plate and the outside of the perforation in the resin film to each other, and the electrode plate A step of removing an inner portion surrounded by perforations in the resin film bonded to the resin film from one end side to the other end side in the direction along one of the long side and the short side forming the rectangle; In the step of forming the perforations, the perforations are formed such that the force required for separating the perforations on the one end side is smaller than the force required for separating the perforations on the other end side.

In the above electrode unit manufacturing method, an electrode unit in which a frame-shaped resin film (that is, a frame body) is joined to the edge portion of the electrode plate can be manufactured. In this method, the resin film before being processed into a frame shape is joined to the electrode plate, and then the inner portion of the perforation is removed. In the resin film in which the perforations are formed, the rigidity of the frame body is maintained by the inner portion before being removed. Therefore, since the resin film can be handled relatively easily, the productivity of the electrode unit is prevented from being lowered. In such a method, if the force required to separate the perforations is too large, the perforations may not be properly separated. On the other hand, if the force required to separate the perforations is too small, the perforations may be cut in an unintended situation, and the rigidity of the frame body may not be maintained. In this method, it is premised that the inner portion of the perforation is removed from one end side toward the other end side. The perforations are formed so that the force required for separating the perforations on the one end side is smaller than that on the other end side. Thereby, the inner portion can be easily separated from the resin film. Further, on the other end side, since the force required for separating the perforations is large, it is possible to prevent the inner part from being unintentionally separated.

Further, in the removing step, the inner portion surrounded by the perforations by the suction roller that relatively moves from one end side to the other end side may be removed from the resin film. With this configuration, the inner portion can be removed from the resin film by winding the inner portion of the perforation with the suction roller.

Further, the perforation has a cut portion obtained by cutting the resin film and a connection portion formed with a constant length between adjacent cut portions, and in the step of forming the perforation, from one end side Perforations may be formed such that the length of the cut portion gradually decreases toward the other end side. By changing the length of the cut portion of the perforation, the force required for cutting the perforation can be easily controlled.

An electrode unit preparation according to one aspect of the present invention is an electrode unit preparation for obtaining an electrode unit that includes an electrode plate and a frame body that surrounds an edge of the electrode plate and is joined to the edge. An electrode plate, and a resin film that is a base material of the frame body joined to the edge of the electrode plate, the resin film has a rectangular perforation along the inner edge of the frame, the perforation is , The force required for separating perforations at one end in the direction along one of the long sides and the short sides forming a rectangle is smaller than the force required for separating perforations at the other end. ing.

According to one aspect of the present invention, it is possible to provide an electrode unit manufacturing method capable of suppressing a decrease in productivity.

It is a schematic sectional drawing which shows an example of the electrical storage apparatus provided with an electrical storage module. It is a schematic sectional drawing which shows the electrical storage module which comprises the electrical storage apparatus of FIG. FIG. 6 is a flowchart for explaining the method of manufacturing the power storage device according to the embodiment. It is a top view which shows an electrode unit. It is sectional drawing which shows an electrode unit. It is a flow figure showing an example of an electrode unit manufacturing process. It is a figure which shows an electrode unit manufacturing process typically. It is a top view which shows the individual resin film in which the perforation was formed. It is a figure for demonstrating a spacer formation process.

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. In the drawings, an XYZ rectangular coordinate system is shown as needed.

The electrode unit manufacturing method according to the present embodiment is a method of manufacturing an electrode unit that constitutes a battery module. First, an example of a power storage device including an electrode module will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing an embodiment of a power storage device. Power storage device 1 shown in FIG. 1 is used as a battery in various vehicles such as forklifts, hybrid vehicles, electric vehicles, and the like. The power storage device 1 includes a module stack 2 including a plurality of stacked power storage modules 4, and a restraining member 3 that applies a restraining load to the module stack 2 in the stacking direction of the module stack 2.

The module stack 2 includes a plurality (here, three) of power storage modules 4 and a plurality (here, four) of conductive plates 5. The electricity storage module 4 is a bipolar battery and has a rectangular shape when viewed from the stacking direction. The electricity storage module 4 is, for example, a secondary battery such as a nickel hydrogen secondary battery, a lithium ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-hydrogen secondary battery will be exemplified.

The electricity 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 module 4 located at the stacking end. A positive electrode terminal 6 is connected to one conductive plate 5 arranged outside 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 power storage module 4 located at the stacking end. The positive electrode terminal 6 and the negative electrode terminal 7 are drawn out, for example, from an edge portion of the conductive plate 5 in a direction intersecting with the stacking direction. The power storage device 1 is charged and discharged by the positive electrode terminal 6 and the negative electrode terminal 7.

Inside the conductive plate 5, a plurality of flow paths 5a for circulating a refrigerant such as air are provided. The flow path 5a extends along, for example, a direction that intersects (orthogonally) with the stacking direction and the pull-out direction of the positive electrode terminal 6 and the negative electrode terminal 7. The conductive plate 5 has a function as a connecting member that electrically connects the power storage modules 4 to each other, and also functions as a heat dissipation plate that radiates the heat generated in the power storage module 4 by circulating a refrigerant in these flow paths 5a. It also has functions. In the example of FIG. 1, the area of the conductive plate 5 viewed 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 smaller than that of the power storage module. 4 may be the same as the area of the electricity storage module 4 or may be larger than the area of the electricity storage module 4.

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

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

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 shown in FIG. As shown in FIG. 2, the electricity storage module 4 includes an electrode stack 11 and a resin sealing body 12 that seals the electrode stack 11. The electrode stack 11 is composed of a plurality of electrodes stacked along the stacking direction D1 of the power storage module 4 with the separator 13 interposed therebetween. These electrodes include a stacked body of a plurality of bipolar electrodes 14, a negative electrode termination electrode 18, and a positive electrode termination electrode 19.

The bipolar electrode 14 has an electrode plate 15 including one surface 15a and the other surface 15b opposite to the one surface 15a, a positive electrode 16 provided on the one surface 15a, and a negative electrode 17 provided on the other surface 15b. ing. The positive electrode 16 is a positive electrode active material layer formed by applying the positive electrode active material to the electrode plate 15. The negative electrode 17 is a negative electrode active material layer formed by applying the negative electrode active material to the electrode plate 15. In the electrode stacked body 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of another bipolar electrode 14 adjacent in one of the stacking directions D1 with the separator 13 interposed therebetween. In the electrode stack 11, the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of another bipolar electrode 14 that is adjacent to the other in the stacking direction D1 with the separator 13 interposed therebetween.

The negative electrode terminal electrode 18 has an electrode plate 15 and a negative electrode 17 provided on the other surface 15b of the electrode plate 15. The negative terminal electrode 18 is arranged at one end in the stacking direction D1 so that the other surface 15b faces the center side in the stacking direction D1 in the electrode stack 11. One surface 15a of the electrode plate 15 of the negative terminal electrode 18 constitutes one outer surface in the stacking direction of the electrode stack 11, and is electrically connected to one conductive plate 5 (see FIG. 1) adjacent to the power storage module 4. It is connected. The negative electrode 17 provided on the other surface 15b of the electrode plate 15 of the negative terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D1 via the separator 13.

The positive terminal electrode 19 has an electrode plate 15 and a positive electrode 16 provided on the one surface 15 a of the electrode plate 15. The positive electrode termination electrode 19 is arranged at the other end in the stacking direction D1 such that the one surface 15a faces the center side in the stacking direction D1 in the electrode stack 11. The positive electrode 16 provided on the one surface 15a of the positive electrode termination electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D1 with the separator 13 in between. The other surface 15b of the electrode plate 15 of the positive electrode termination electrode 19 constitutes the other outer surface in the stacking direction of the electrode stack 11, and is electrically connected to the other conductive plate 5 (see FIG. 1) adjacent to the power storage module 4. It is connected.

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 foil made of nickel. The edge portion 15c of the electrode plate 15 has a rectangular frame shape and is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. Examples of the positive electrode active material forming the positive electrode 16 include nickel hydroxide. Examples of the negative electrode active material forming the negative electrode 17 include a hydrogen storage alloy. In the present embodiment, the formation area of the negative electrode 17 on the other surface 15b of the electrode plate 15 is slightly larger than the formation area 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), and a woven or non-woven fabric made of polypropylene, methyl cellulose and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound. The separator 13 is not limited to the sheet shape, and a bag shape may be used.

The sealing body 12 is formed of, for example, an insulating resin into a rectangular tubular shape as a whole. The sealing body 12 is provided on the side surface 11 a of the electrode laminate 11 so as to surround the edge portion 15 c of the electrode plate 15. The sealing body 12 holds the edge portion 15c on the side surface 11a. The sealing body 12 surrounds the plurality of first sealing portions 21 (frame bodies) joined to the edge portion 15c of the electrode plate 15 and the first sealing portion 21 from the outside along the side surface 11a. It has the 2nd sealing part 22 joined to each of the sealing parts 21. The first sealing portion 21 and the second sealing portion 22 are, for example, an insulating resin having alkali resistance. Examples of the constituent material of the first sealing portion 21 and the second sealing portion 22 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like.

The first sealing portion 21 is continuously provided on the one surface 15a of the electrode plate 15 over the entire circumference of the edge portion 15c, and has a rectangular frame shape when viewed from the stacking direction D1. In the present embodiment, the first sealing portion 21 is provided not only for the electrode plate 15 of the bipolar electrode 14 but also for the electrode plate 15 of the negative terminal electrode 18 and the electrode plate 15 of the positive terminal electrode 19. In the negative electrode termination electrode 18, the first sealing portion 21 is provided on the edge portion 15c of the one surface 15a of the electrode plate 15, and in the positive electrode termination electrode 19, both edge portions of the one surface 15a and the other surface 15b of the electrode plate 15 are provided. The first sealing portion 21 is provided at 15c.

The first sealing portion 21 is welded to the one surface 15a of the electrode plate 15 by ultrasonic waves or heat, for example, and is hermetically bonded. The first sealing portion 21 is, for example, a film having a predetermined thickness in the stacking direction D1. The inside of the first sealing portion 21 is located between the edge portions 15c of the electrode plates 15 adjacent to each other in the stacking direction D1. The outer side of the first sealing portion 21 projects beyond the edge of the electrode plate 15, and the tip portion thereof is embedded in the second sealing portion 22. The first sealing portions 21 adjacent to each other along the stacking direction D1 may be separated from each other or may be in contact with each other. The outer edge portions of the first sealing portion 21 may be joined to each other by, for example, hot plate welding.

An area where the electrode plate 15 and the first sealing portion 21 overlap is a joining area K between the electrode plate 15 and the first sealing portion 21. In the bonding region K, the surface of the electrode plate 15 is roughened. The roughened area may be only the bonding area K, but in the present embodiment, the entire surface of the electrode plate 15 is roughened. The roughening can be realized by forming a plurality of protrusions by electrolytic plating, for example. By forming the plurality of protrusions, the resin in a molten state enters between the plurality of protrusions formed by roughening at the bonding interface between the electrode plate 15 and the first sealing portion 21, and the anchor effect is exhibited. It Thereby, the bonding strength between the electrode plate 15 and the first sealing portion 21 can be improved. The protrusion formed during the roughening has a shape that is tapered from the base end side toward the tip end side, for example. As a result, the cross-sectional shape between the adjacent protrusions becomes an undercut shape, and the anchor effect can be enhanced.

The second sealing portion 22 is provided outside the electrode laminate 11 and the first sealing portion 21, and constitutes the outer wall (housing) of the power storage module 4. The second sealing portion 22 is formed by, for example, resin injection molding, and extends over the entire length of the electrode stacked body 11 along the stacking direction D1. The second sealing portion 22 has a rectangular frame shape extending in the stacking direction D1 as an axial direction. The second sealing portion 22 is welded to the outer surface of the first sealing portion 21 by heat during injection molding, for example.

The first sealing portion 21 and the second sealing portion 22 form an internal space V between adjacent electrodes and seal the internal space V. More specifically, the second sealing part 22 together with the first sealing part 21 is between the bipolar electrodes 14 adjacent to each other in the stacking direction D1, and the negative electrode termination electrode 18 adjacent to each other in the stacking direction D1. And the bipolar electrode 14, and between the positive electrode termination electrode 19 and the bipolar electrode 14 which are adjacent to each other along the stacking direction D1 are sealed. As a result, airtightly partitioned internal spaces V are formed between the adjacent bipolar electrodes 14, between the negative electrode termination electrode 18 and the bipolar electrode 14, and between the positive electrode termination electrode 19 and the bipolar electrode 14. ing. In this internal space V, an electrolytic solution (not shown) containing an alkaline solution such as an aqueous potassium hydroxide solution is contained. The electrolytic solution is impregnated in the separator 13, the positive electrode 16, and the negative electrode 17. A liquid injection port for injecting a liquid injection port into the internal space V is provided on the side surface of the sealing body 12.

Next, a method for manufacturing the above-described power storage device will be described.

FIG. 3 is a flowchart showing an example of a manufacturing process of a power storage device. As shown in FIG. 3, the manufacturing process of the power storage device includes an electrode unit manufacturing process (S01), a laminating process (S02), a sealing body forming process (S03), an injection process (S04), and an assembling process. (S05) is included.

In the electrode unit manufacturing step S01, the electrode unit 30 is manufactured by the electrode unit manufacturing method described later. The electrode unit 30 includes the bipolar electrode 14 and the rectangular frame-shaped first sealing portion 21 joined to the edge portion 15 c of the bipolar electrode 14.

In the laminating step S02, the electrode units 30 are laminated via the separator 13 to obtain a laminated body. In addition, the negative electrode termination electrode 18 and the positive electrode termination electrode 19 are further laminated on the laminated end of the laminated body of the electrode unit 30 to obtain the electrode laminated body 11. Upon stacking, the rectangular frame-shaped first sealing portion 21 is joined to the edge portions 15c of the electrode plates 15 of the negative electrode termination electrode 18 and the positive electrode termination electrode 19 by welding or the like.

In the sealing body forming step S03, the second sealing portion 22 is formed on the electrode laminated body 11 by, for example, injection molding, and the sealing body 12 is formed. Specifically, the electrode laminate 11 obtained in the laminating step S02 is placed in a mold, and a resin material having fluidity is poured into the mold to form a second sealing on the side surface of the electrode laminate 11. The part 22 is formed. The first sealing portions 21 of the electrode laminated body 11 are bonded to each other by the second sealing portion 22, and the sealing body 12 is obtained. At this time, a liquid injection port for injecting the electrolytic solution into the internal space V is formed on the side surface of the sealing body 12.

In the injection step S04, the electrolytic solution is injected into each of the internal spaces V of the electrode laminate 11. Here, the electrolytic solution is injected into the internal space V through the injection port provided on the side surface of the sealing body 12. After the injection of the electrolytic solution, the injection port is sealed with a sealing material or the like to obtain the electricity storage module 4. A pressure adjusting valve or the like may be provided at the liquid injection port instead of the sealing material.

In the assembly step S05, first, the plurality of power storage modules 4 are stacked with the conductive plate 5 interposed therebetween. At this time, it is preferable to connect the positive electrode terminal 6 to the conductive plate 5 arranged on one side in the stacking direction in advance and to connect the negative electrode terminal 7 to the conductive plate 5 arranged on the other side in advance. Next, a pair of end plates 8 is arranged at both ends of the electricity storage module 4 in the stacking direction with the electrically insulating film F interposed therebetween. Then, the fastening bolt 9 is inserted into the insertion hole 8 a of the end plate 8, and the nut 10 is screwed onto the tip of the fastening bolt 9 protruding from the end plate 8. As a result, the plurality of power storage modules 4 are unitized to obtain the power storage device 1.

Next, the electrode unit manufacturing method in the electrode unit manufacturing step S01 will be described in detail. First, the details of the electrode unit 30 manufactured by the electrode unit manufacturing method will be described. FIG. 4 is a plan view showing the electrode unit. FIG. 5 is a sectional view showing the electrode unit. Note that the positive electrode 16 and the negative electrode 17 are not shown in FIG. 4. The electrode unit 30 has a rectangular shape in a plan view and is composed of the bipolar electrode 14 and the first sealing portion 21. The first sealing portion 21 has a rectangular frame shape. The first sealing portion 21 surrounds the edge portion 15c of the electrode plate 15 and is joined to the edge portion 15c. The inner edge 25s of the first sealing portion 21 is located inside the peripheral edge 15d of the electrode plate 15. The outer periphery of the first sealing portion 21 is folded back at a position outside the peripheral edge 15d of the electrode plate 15 to partially form two layers. That is, the first sealing portion 21 includes the first layer 25 joined to the bipolar electrode 14 and the second layer 27 folded back to the first layer 25 side and stacked. The second layer 27 is provided on the surface 25 a of the first layer 25, which is opposite to the bonding surface with the bipolar electrode 14. The inner peripheral edge of the first layer 25 (that is, the inner edge 25s of the first sealing portion 21) is located inside the inner edge 27s of the second layer 27. The separator 13 may be joined to the inner peripheral edge portion 25b of the first layer 25 including the inner edge 25s after the removing step S15. That is, the second layer 27 functions as a spacer layer for disposing the separator 13 between the stacked electrode units 30. In the electrode unit 30, a joint region between the first sealing portion 21 and the electrode plate 15 is formed in a region from the inner edge 25s of the first sealing portion 21 to the peripheral edge 15d of the electrode plate 15.

FIG. 6 is a flowchart showing an example of the electrode unit manufacturing process. FIG. 7 is a diagram schematically showing an electrode unit manufacturing process. As shown in FIGS. 6 and 7, the electrode unit manufacturing step S01 includes a film processing step S11, an arrangement step S12, a joining step S13, a spacer forming step S14, and a removing step S15. As an example, an example will be described in which the resin film, which is the base material of the first sealing unit 21, is transferred in the respective steps while being transferred in the transfer direction D2. In the illustrated example, the strip-shaped resin film 120 fed from the original roll 119 is shown as the base material of the first sealing portion 21.

In the film processing step S11, the resin film 120 fed from the original roll 119 is cut into individual pieces, and perforations 125 are formed inside the individual resin film 121. As an example, the film processing step S11 can be carried out by a processing device provided with a punching blade for cutting the resin film 121 into individual pieces and a perforation processing blade.

FIG. 8 is a plan view showing an individual resin film on which perforations are formed. In FIG. 8, the positions where the bipolar electrodes 14 are to be joined are indicated by broken lines. The resin film 121 that has been separated into individual pieces through the film processing step S11 has rectangular cutout portions at the four corners. The resin film 121 includes a first layer 25 having a rectangular frame shape, a second layer 27 continuous to each side of the first layer 25, and an inner portion 124 connected to the inside of the first layer 25 by perforations 125. Have and. In the drawing, the boundary between the first layer 25 and the second layer 27 is shown by a chain double-dashed line. The two-dot chain line is the folding line 127 in the spacer forming step S14.

The perforation 125 is a processed portion formed to facilitate the cutting of the resin film 121. The perforation 125 is formed along the inner edge 27s of the first sealing portion 21. In the example of FIG. 8, perforations 125 having a rectangular shape in plan view are formed. The perforation 125 has a cutting portion 125a and a connecting portion 125b. The cut portion 125a is a portion where the resin film 121 is completely cut in the thickness direction. The connecting portion 125b is a portion where a portion outside the perforation 125 and an inner portion 124 surrounded by the perforation 125 are continuous. The portion outside the perforation 125 is the portion that becomes the first sealing portion 21. In this embodiment, the thickness of the resin film 121 may be, for example, about 100 to 200 μm. The perforation 125 is formed inside the position where the bipolar electrode 14 is to be joined. By forming the perforations 125 in the resin film 121, the inner portion 124 can be separated from the resin film 121 without using a cutting tool or the like in the subsequent steps.

In the perforation 125, the force required for separating the perforation 125 on one end side in the direction along the long side or the short side forming the rectangle is greater than the force required for separating the perforation 125 on the other end side. It is formed to be small. In the embodiment, the force required to separate the perforation 125 on the downstream side (one end side) in the transport direction D2 is the upstream side (the other end side) in the transport direction, with the direction along the long side direction being the transport direction D2. The perforation 125 is formed so as to be smaller than the force required for separating the perforation 125. In the illustrated perforation 125, the size of the connecting portion 125b is constant regardless of the pitch P. That is, the connecting portion 125b is formed between adjacent cutting portions 125a with a certain length in the extending direction of the perforations 125. In this case, the force required to separate the perforations 125 depends on the pitch P of the perforations 125. That is, if the pitch P is small, the connecting portions 125b are densely formed, and the force required for disconnection increases. On the other hand, if the pitch P is large, the connecting portions 125b are formed sparsely, and the force required for disconnection becomes small. When the pitch P is small, the length of the cut portion 125a is small, and when the pitch P is large, the length of the cut portion 125a is large.

In the film processing step S11, the resin film 121 is processed so that the pitch P of the perforations 125 along the transport direction gradually decreases from the downstream side toward the upstream side. That is, in the perforation 125 along the transport direction, the length of the cut portion 125a gradually decreases from the downstream side to the upstream side. The pitch P of the perforations 125 along the short side direction on the downstream side is equal to the pitch P of the perforations 125 on the most downstream side in the longitudinal direction. The pitch P of the perforations 125 along the short side direction on the upstream side is equal to the pitch P of the perforations 125 in the most upstream direction in the longitudinal direction. The pitch P of the perforations 125 along the short side direction on the upstream side may be equal to the pitch P of the perforations 125 on the most downstream side in the longitudinal direction.

In the subsequent arrangement step S12, the resin film 121 conveyed in the conveying direction is arranged on the bipolar electrode 14. In this arranging step S12, the resin film 121 is arranged on the bipolar electrode 14 so that the bipolar electrode 14 overlaps the position shown by the broken line in FIG.

In the joining step S13, the edge portion 15c of the bipolar electrode 14 and the region of the resin film 121 outside the perforations 125 are joined in a state where the bipolar electrode 14 and the resin film 121 overlap each other. As a method for joining the first sealing portion 21 and the bipolar electrode 14, for example, welding by ultrasonic waves or heat may be mentioned. The first sealing portion 21 is similarly bonded to the negative electrode termination electrode 18 and the positive electrode termination electrode 19.

In the present embodiment, the electrode unit preparation body 129 is formed by joining the bipolar electrode 14 and the resin film 121. That is, the electrode unit preparation 129 includes the bipolar electrode 14 and the resin film 121 bonded to the edge portion 15c of the bipolar electrode 14, and the resin film 121 is provided with perforations 125. The “electrode unit preparation” means a state before being processed into an electrode unit.

FIG. 9 is a diagram for explaining the spacer forming step, and is a plan view showing the bipolar electrode 14 and the resin film 121 that have undergone the spacer forming step. In the spacer forming step S14, the second layer 27 of the resin film 121 is folded back at the position of the folding line 127, so that the second layer 27 is laminated on the first layer 25. As shown in FIG. 9, the four second layers 27 folded back along the folding line 127 form a rectangular frame shape.

In the removing step S15, the inner portion 124 of the resin film 121 surrounded by the perforations 125 is removed from the electrode unit preparation body 129. In the removing step S15, the force that separates the perforation 125 in the direction along either the long side or the short side of the perforation 125 having a rectangular shape is designed to be small, and the perforation 125 of the perforation 125 is designed from one side to the other side. The inner portion 124 is removed. In the present embodiment, the perforation 125 on the downstream side in the transport direction D2 is easily formed. Therefore, the inner portion 124 of the perforation 125 is cut off from the downstream side in the transport direction D2 toward the upstream side.

For example, in the removing step S15, the inner portion 124 surrounded by the perforations 125 is removed from the electrode unit preparation body 129 by the suction roller 130 that relatively moves from the downstream side to the upstream side. The suction roller 130 has a plurality of suction holes on its roller surface and sucks the conveyed work. In the present embodiment, as shown in FIG. 7, since the electrode unit preparation body 129 is transported in the transport direction D2, the position of the suction roller 130 may be fixed. The rotating suction roller 130 sucks the inner portion 124 surrounded by the perforations 125 and winds the inner portion 124, so that the perforations 125 are broken. As a result, the inner portion 124 surrounded by the perforations 125 is separated from the resin film 121. The separated inner portion 124 is discarded, for example. By separating the inner portion 124 from the resin film 121, the electrode unit 30 (see FIG. 4) in which the first sealing portion 21 and the bipolar electrode 14 are joined is manufactured.

In the electrode unit manufacturing method described above, the electrode unit 30 in which the frame-shaped resin film (that is, the first sealing portion 21) is bonded to the edge portion 15c of the bipolar electrode 14 can be manufactured. In this method, the resin film 121 before being processed into a frame shape is joined to the bipolar electrode 14, and then the inner portion 124 of the perforation 125 is removed. In the resin film 121 on which the perforations 125 are formed, the rigidity of the first sealing portion 21 is maintained by the inner portion 124 before being removed. Therefore, the resin film 121 can be handled relatively easily. Therefore, the decrease in productivity of the electrode unit 30 is suppressed.

When cutting along perforations formed with a uniform pitch, the greatest force is required at the start of cutting as compared to the middle and end stages of cutting. In this case, if the force required to separate the perforations is too large, the perforations may not be cut properly. On the other hand, if the force required to separate the perforations is too small, the perforations may be cut in an unintended situation, and the rigidity of the first sealing portion 21 may not be maintained. In this method, the inner part 124 of the perforation 125 is removed from the downstream side to the upstream side in the transport direction. The perforations 125 are formed so that the force required for separating the perforations 125 on the downstream side is smaller than that on the upstream side. Therefore, the inner portion 124 can be easily separated from the resin film 121 along the perforations 125. Further, on the upstream side, since the force required for separating the perforations 125 is large, unintentional separation of the inner portion 124 is suppressed.

If the joining step S13 and the removing step S15 are performed without passing through the film processing step S11, the inner portion 124 needs to be cut off with a blade or the like. In this case, it is possible that the bipolar electrode 14 is damaged by a blade or the like. In this embodiment, since the perforations 125 are formed in the film processing step S11, the inner portion 124 can be removed without using a blade or the like.

In addition, in the removing step S15, the inner portion 124 is removed from the resin film 121 by the suction roller 130 that relatively moves from the downstream side to the upstream side. With this configuration, the inner portion 124 of the perforation 125 can be wound by the suction roller 130 to remove the inner portion 124 from the resin film 121.

Further, in the film processing step S11, the perforations 125 are formed such that the pitch gradually decreases from the downstream side to the upstream side in the transport direction. In this way, by changing the pitch of the perforations 125, it is possible to easily control the force required to separate the perforations 125.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments.

For example, although an example in which the direction along the long side of the perforation 125 is set as the transport direction D2 of the resin film is shown, the transport direction of the resin film is not limited to this. For example, the direction along the short side direction of the perforation 125 may be the transport direction of the resin film.

Further, although the example in which the connecting portion 125b is formed to have a constant length is shown, the present invention is not limited to this. The force required to cut perforations also depends on the length of the connection. Therefore, the force required for cutting perforations may be controlled by changing the length of the connecting portion.

14... Bipolar electrode, 15... Electrode plate, 15c... Edge part, 21... 1st sealing part (frame body), 30... Electrode unit, 121... Resin film, 125... Perforation, 125a... Cutting part, 125b... Connection part.

Claims (5)

An electrode unit manufacturing method for manufacturing an electrode unit including an electrode plate and a frame body that surrounds an edge portion of the electrode plate and is joined to the edge portion,
A step of forming a rectangular perforation along the inner edge of the frame in the resin film that is the base material of the frame,
A step of joining the edge portion of the electrode plate and the outside of the perforations in the resin film to each other;
The inner portion surrounded by the perforations in the resin film joined to the electrode plate, from the one end side in the direction along one of the long side and the short side forming the rectangle toward the other end side. Including a step of removing from the resin film,
In the step of forming the perforations, the perforations are formed such that the force required for separating the perforations on the one end side is smaller than the force required for separating the perforations on the other end side. Unit manufacturing method. The electrode unit manufacturing method according to claim 1, wherein in the removing step, an inner portion surrounded by the perforations is removed from the resin film by a suction roller that relatively moves from the one end side to the other end side. .. The perforation has a cut portion in which the resin film is cut, and a connection portion formed with a constant length between adjacent cut portions,
3. The electrode unit according to claim 1, wherein in the step of forming the perforations, the perforations are formed so that the length of the cut portion gradually decreases from the one end side toward the other end side. Production method. An electrode unit and an electrode unit preparation body for enclosing an edge portion of the electrode plate and obtaining an electrode unit including a frame joined to the edge portion,
The electrode plate,
A resin film which is a base material of the frame joined to an edge portion of the electrode plate,
The resin film has a rectangular perforation along the inner edge of the frame,
In the perforation, the force required to separate the perforations on one end side in the direction along the long side or the short side forming the rectangle is smaller than the force required to separate the perforations on the other end side. An electrode unit preparatory body that is formed so as to be. The perforation has a cut portion in which the resin film is cut, and a connection portion formed with a constant length between the adjacent cut portions,
The electrode unit preparation body according to claim 4, wherein the perforation is formed such that the length of the cut portion gradually decreases from the one end side toward the other end side.

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