Annular spacer member disposed at peripheral edge portion of current collector adjacent in stacking direction of bipolar battery, and method for manufacturing bipolar battery

Abstract

To improve productivity of a bipolar battery.SOLUTION: An annular spacer member disposed at a peripheral edge portion of a current collector adjacent in a stacking direction of a bipolar battery according to the present disclosure includes a frame portion disposed so as to surround a peripheral edge portion of a bipolar electrode, and a plurality of cut portions formed from an inner edge portion toward an outer edge portion of the frame portion and shorter than a distance from the inner edge portion to the outer edge portion. The frame portion is laminated on the bipolar electrode in a state where a plurality of continuous frame portions are conveyed in the same direction as the conveying direction of the bipolar electrode. The frame portion is cut out using a part of the plurality of cutting portions after the spacer member is laminated on the bipolar electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to annular spacer members arranged on the peripheral edges of adjacent current collectors in the stacking direction of a bipolar battery, and a method for manufacturing a bipolar battery. [Background technology]

[0002] A bipolar battery is known that has multiple bipolar electrodes, each with a positive electrode on one side of a current collector and a negative electrode on the other side. A resin frame is attached to the edge of each electrode to seal the gap between adjacent electrodes in the stacking direction. The resin frame has a communication port for injecting an electrolyte into the bipolar battery.

[0003] Patent Document 1 discloses a technique for manufacturing a resin frame having a communication port. In Patent Document 1, a first resin part having a U-shaped end layer structure is formed, and a second resin part having a rectangular two-layer structure with a step portion that forms the communication port is bonded to both ends of the first resin part. The rectangular second resin part is half the thickness of the first resin part and is made up of a first resin film that corresponds to the length of both ends of the first resin part, and two second resin films that are shorter than the first resin film and are arranged on the first resin film with a width of the communication port between them. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-129070 Summary of the Invention [Problem to be solved by the invention]

[0005] Some bipolar batteries have multiple inlets. In this case, it is necessary to prepare resin frames with communication holes formed in different positions, equal to the number of rows of the inlets. When forming a resin frame with communication holes using U-shaped members and strip-shaped members, as in Patent Document 1, it is necessary to prepare multiple members of different lengths, which poses a problem of poor productivity.

[0006] The present disclosure has been made in consideration of such problems, and aims to provide an annular spacer member that is placed on the peripheral portion of adjacent current collectors in the stacking direction of a bipolar battery, and a method for manufacturing a bipolar battery, which can improve the productivity of bipolar batteries. [Means for solving the problem]

[0007] The annular spacer member of the present disclosure, which is arranged on the peripheral portion of adjacent current collectors in the stacking direction of a bipolar battery, comprises a frame portion arranged to surround the peripheral portion of the bipolar electrode, and a plurality of cut portions formed from the inner edge portion of the frame portion toward the outer edge portion, the cut portions being shorter than the distance from the inner edge portion to the outer edge portion.

[0008] The method for manufacturing a bipolar battery according to the present disclosure includes forming a spacer member having a frame portion arranged to surround the peripheral portion of a bipolar electrode and a plurality of cut portions formed from the inner edge portion of the frame portion toward the outer edge portion and shorter than the distance from the inner edge portion to the outer edge portion, and after stacking the spacer member on the bipolar electrode, cutting out a predetermined portion of the frame portion using some of the cut portions. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to improve the productivity of bipolar batteries. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a cross section of a bipolar battery according to an embodiment. [Figure 2]FIG. 1 is a flow diagram illustrating a method for manufacturing a bipolar battery according to an embodiment. [Figure 3] 10A to 10C are diagrams illustrating a molding process of the resin frame. [Figure 4] 10A and 10B are diagrams showing the process of arranging and bonding a lower sealing material and a bipolar electrode (left side), and the process of arranging and bonding an upper sealing material (right side). [Figure 5] 10A and 10B are diagrams illustrating the configuration of a resin frame that serves as a spacer. [Figure 6] 10A and 10B are diagrams illustrating cut portions formed in the resin frame. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In addition, the same elements in each drawing are designated by the same reference numerals, and duplicate explanations have been omitted as necessary.

[0012] The embodiments relate to a bipolar secondary battery (electricity storage module) mounted as a battery in various vehicles such as hybrid vehicles and electric vehicles. The bipolar battery according to the embodiments is a secondary battery such as a lithium ion secondary battery or a nickel-metal hydride secondary battery. The present disclosure can also be applied to an electricity storage module such as an electric double layer capacitor. In the following description, a lithium ion secondary battery is used as an example.

[0013] FIG. 1 is a cross-sectional view of a bipolar battery according to an embodiment. The bipolar battery 10 includes an electrode stack 20 in which positive and negative electrodes are alternately stacked while being insulated from each other. The electrode stack 20 includes a plurality of bipolar electrodes 1, a plurality of separators 2, and a pair of outermost current collectors 3. The plurality of bipolar electrodes 1 are stacked on top of each other. The electrode stack 20 has a rectangular shape when viewed in the stacking direction of the plurality of bipolar electrodes 1. Separators 2 are disposed between adjacent bipolar electrodes 1.

[0014] Each bipolar electrode 1 has a current collector 11, a positive electrode 12, and a negative electrode 13. The current collector 11 is made of a metal member such as Al foil. The current collector 11 is, for example, rectangular in top view. The positive electrode 12 is provided on one surface of the current collector 11. The positive electrode 12 is formed by coating one surface of the current collector 11 with a positive electrode active material. Examples of the positive electrode active material include lithium-containing metal oxides and lithium-containing phosphates. Examples of lithium-containing metal oxides include Li(NiCoMn)O2 and Li(NiCoAl)O2. Examples of lithium-containing phosphates include LiFePO4. The negative electrode 13 is provided on the other surface of the current collector 11. The negative electrode 13 is formed by coating the other surface of the current collector with a negative electrode active material. Examples of negative electrode active materials include carbon-based negative electrode active materials such as graphite, graphitizable carbon, and non-graphitizable carbon, and alloy-based negative electrode active materials containing silicon (Si), tin (Sn), etc. The region of the current collector 11 where the negative electrode 13 is formed may be slightly larger than the region where the positive electrode 12 is formed. The peripheral portion of the current collector 11 is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. In the uncoated region, the current collector is exposed.

[0015] The separator 2 is disposed between the positive electrode 12 and the negative electrode 13 of the adjacent bipolar electrodes 1. The separator 2 allows ions to pass through while insulating the positive electrode 12 and the negative electrode 13 from direct contact. The separator 2 has a rectangular shape. The separator 2 is formed, for example, in a sheet shape. The separator 2 is formed of a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), or a nonwoven or woven fabric made of PE, PP, polyethylene terephthalate (PET), methyl cellulose, or the like. The separator 2 may be smaller than the current collector 11 and larger than the positive electrode 12 and the negative electrode 13 when viewed in the stacking direction.

[0016] A pair of outermost current collectors 3 are disposed on the outsides of the multiple bipolar electrodes 1 in the stacking direction. One of the outermost current collectors 3 has a positive electrode 31 formed thereon. This outermost current collector 3 corresponds to the positive electrode terminal electrode. The positive electrode 31 of the positive electrode terminal electrode faces the negative electrode 13 of the adjacent bipolar electrode 1 via a separator 2. The other outermost current collector, not shown in FIG. 1, has a negative electrode formed thereon. This other outermost current collector corresponds to the negative electrode terminal electrode. The negative electrode of the negative electrode terminal electrode faces the positive electrode 12 of the adjacent bipolar electrode 1 via the separator 2. The peripheral portions of the pair of outermost current collectors 3 are uncoated regions where no positive electrode active material or negative electrode active material is applied. The current collectors are exposed in the uncoated regions.

[0017] A pair of adjacent current collectors 11, and the positive electrode 12, separator 2, and negative electrode 13 arranged between the pair of current collectors 11, form one cell. That is, the electrode stack 20 includes a plurality of cells stacked on top of each other. Of the plurality of cells, the outer current collector of the outermost cell becomes the outermost current collector 3. That is, in the bipolar battery 10, each bipolar electrode 1 serves as both the positive electrode and the negative electrode of the adjacent cells, and the plurality of cells are connected in series.

[0018] An external current collector 5 may be provided on the outside of each of the pair of outermost current collectors 3 via a conductive adhesive. A positive electrode terminal is connected to one of the external current collectors 5. A negative electrode terminal is connected to the other external current collector (not shown). A bipolar battery has a structure in which current is extracted from the electrode stack via the external current collectors via the positive electrode terminal and the negative electrode terminal. The external current collector 5 is, for example, a metal sheet. As the external current collector 5, for example, a conductive metal such as stainless steel, iron, copper, aluminum, titanium, or nickel is used. The material of the external current collector 5 is not particularly limited, and a metal can be appropriately used depending on the purpose.

[0019] The bipolar battery 10 includes a cylindrical sealing member 4 that extends in the stacking direction of the bipolar electrodes 1 and houses the electrode stack 20. The sealing member 4 restricts the movement of gas and electrolyte between the cells, thereby ensuring insulation between adjacent cells.

[0020] The sealing member 4 is made of a resin material such as polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE). The sealing member 4 holds the ends of the bipolar electrode 1, separator 2, and outermost current collector 3. The uncoated region of the bipolar electrode 1, where the current collector is exposed, is embedded and held in the sealing member 4. That is, the sealing member 4 is configured to surround the electrode stack 20. When viewed from the stacking direction side of the bipolar electrode 1, the sealing member 4 has, for example, a rectangular shape. That is, the sealing member 4 has, for example, a square cylindrical shape.

[0021] The sealing member 4 includes three resin frames. These three resin frames are a lower sealing material 41, an upper sealing material 42, and a spacer 43. The sealing member 4 has a layered structure in which the lower sealing material 41, the upper sealing material 42, and the spacer 43 are repeatedly layered in this order. The lower sealing material 41 and the upper sealing material 42 each have a rectangular ring shape. The spacer 43 has a rectangular ring shape with a portion missing that corresponds to the liquid injection port described below. In other words, the spacer 43 is a spacer member that is provided on the periphery of the bipolar electrode 1 and has a cutout portion that serves as the liquid injection port. The sealing member 4 is formed by joining adjacent resin frames in the stacking direction.

[0022] The lower sealing material 41 is provided below the peripheral edge of the current collector 11 of the bipolar electrode 1, over the entire periphery of the current collector 11. The lower sealing material 41 is bonded to the current collector 11 of the bipolar electrode 1. The upper sealing material 42 is provided above the peripheral edge of the current collector 11 of the bipolar electrode 1, over the entire periphery of the current collector 11. The upper sealing material 42 is bonded to the peripheral edge of the current collector 11 of the bipolar electrode 1. The lower sealing material 41 and the upper sealing material 42 are also bonded together. The peripheral edge of the current collector 11 of the bipolar electrode 1 is sandwiched between the lower sealing material 41 and the upper sealing material 42, thereby holding the peripheral edge.

[0023] The separator 2 is placed on the upper sealant 42. The peripheral edge of the separator 2 is bonded to the upper sealant 42. The spacer 43 is provided above the peripheral edge of the separator 2, around the entire periphery of the peripheral edge. The spacer 43 is bonded to the peripheral edge of the separator 2. The upper sealant 42 and the spacer 43 are also bonded together. The peripheral edge of the separator 2 is held in place by sandwiching it between the upper sealant 42 and the spacer 43. In this embodiment, the current collector 11 of the bipolar electrode 1 and the separator 2 are bonded to the resin frame by thermal welding using a laser. The bipolar electrode 1, separator 2, lower sealant 41, upper sealant 42, and spacer 43 constitute an electrode unit.

[0024] By stacking multiple bipolar electrodes 1 and a pair of outermost current collectors 3 using a lower sealing material 41, an upper sealing material 42, and a spacer 43, the peripheral edge of each current collector is held in a state of being embedded in the sealing material 4. As a result, an internal space is formed between adjacent current collectors 11 in the stacking direction, which is partitioned airtight and watertight by the current collectors 11 and the sealing material 4. An electrolyte solution containing lithium ions as carrier ions is accommodated in the internal space. For example, the electrolyte solution can be a carbonate-based solvent in which a lithium salt is dissolved at a predetermined concentration. Examples of carbonate-based solvents include fluoroethylene carbonate (FEC) and ethylene carbonate (EC). Examples of lithium salts include hexafluorophosphate. The spacer 43 is provided with a liquid injection port (not shown). The liquid injection port is used to inject the electrolyte solution into the internal space formed between adjacent current collectors 11. The liquid injection port can also be used as a communication port for a pressure adjustment valve that opens and closes depending on the internal pressure in the sealing member 4. A pressure adjustment unit may be provided in the communication port. The pressure adjustment unit may assist or complement the function of the communication port as a pressure adjustment valve.

[0025] In the embodiment, multiple liquid inlet ports are formed in the bipolar battery 10. The liquid inlet ports may be formed, for example, so as to be lined up on one side surface of the electrode stack 20. In other words, the positions of the cutouts that serve as liquid inlet ports may differ among the multiple stacked spacers 43.

[0026] Next, a method for manufacturing a bipolar battery will be described. FIG. 2 is a flow diagram illustrating a method for manufacturing a bipolar battery according to an embodiment. As shown in FIG. 1, first, an electrode forming step (S101) is performed to prepare a bipolar electrode 1. The bipolar electrode 1 is obtained, for example, from a roll of a strip-shaped current collector sheet (current collector sheet roll). The current collector sheet has a positive electrode 12 and a negative electrode 13 intermittently coated in areas corresponding to the individual bipolar electrodes 1. The current collector sheet is unwound and cut at predetermined positions to obtain the individual bipolar electrodes 1.

[0027] Meanwhile, in parallel with the molding process of the bipolar electrode 1, a molding process of the lower seal material 41 is carried out (S201). FIG. 3 is a diagram illustrating the molding process of the resin frame. FIG. 3 shows a schematic configuration of a coating device 200. The coating device 200 can be used when forming the resin frames that will become the lower seal material 41, the upper seal material 42, and the spacer 43.

[0028] The coating device 200 includes a melting station (not shown) that stores molten resin material. The molten resin material is supplied to a first coating unit 201. The first coating unit 201 coats the resin material onto a first roll 202 made of metal, for example, so as to form two continuous parallel straight portions 101 at a predetermined interval in the width direction of the first roll 202. The coating device 200 may include a pump that adjusts the amount of resin material to be coated. The resin material is introduced between the first roll 202 and the second roll 203 and is transported following the contour of the circumferential surface of the second roll 203. The first roll 202 and the second roll 203 sandwich the resin material and cool it to form a film-like resin.

[0029] The resin material is then introduced between the second roll 203 and the third roll 204 and transported to the second coating unit 205. The molten resin material is supplied to the second coating unit 205. The second coating unit 205 intermittently coats the resin material onto the third roll 204, which is made of metal, for example. This allows the second coating unit 205 to form a plurality of connecting portions 102, which connect the two linear portions 101 formed by the first coating unit 201, at predetermined intervals in the transport direction. In other words, the resin material is formed into a ladder-like shape with a plurality of continuous resin frames 100.

[0030] The continuous resin frame 100 is transported to a fourth roll 206, where it is cooled and formed into a film-like resin. The fourth roll 206 aligns the transport direction of the continuous resin frame 100 with the unwinding direction of a release film 103, which is a strip-shaped release material wound into a roll. The continuous resin frame 100 is placed, for example, on top of the unwound portion of the release film 103. Note that instead of the release film 103, for example, a stainless steel belt conveyor may be used.

[0031] The continuous resin frame 100 is then trimmed to remove unnecessary portions, such as excess portions, so as to obtain the desired ladder-shaped continuous resin frame 100. This forms an opening 104 of the desired size in the resin frame 100. A known cutout die, such as a Thomson die, can be used for the trimming process. By processing the edges of the resin frame 100 in this manner, the outer width of the resin frame 100, the width and height of the inner peripheral portion of the resin frame 100, and the line widths of the linear portions 101 and connecting portions 102 can be adjusted to the desired sizes. Here, the width refers to the length of the resin frame 100 in a direction perpendicular to the conveyance direction, and the height refers to the length of the resin frame 100 along the conveyance direction. Here, the length direction of the release film 103 on which the continuous resin frame 100 is formed is defined as the long side, and the width direction is defined as the short side.

[0032] Next, an electrode placement and welding process (S102) is performed in which individual bipolar electrodes 1 are placed on and welded to the lower sealing material 41. FIG. 4 shows the placement and bonding process (left side) of the lower sealing material 41 and the bipolar electrode 1, and the placement and bonding process (right side) of the upper sealing material 42. The resin frames 100 that become the lower sealing material 41 and the upper sealing material 42 have the same configuration. In FIG. 4, the lower resin frame 100 that becomes the lower sealing material 41 is referred to as a lower resin frame 100L, and the upper resin frame 100 that becomes the upper sealing material 42 is referred to as an upper resin frame 100U.

[0033] As shown in FIG. 4, a bipolar electrode 1 is placed on each resin frame 100 (lower sealing material 41) while a continuous series of lower resin frames 100L is being transported. The dimensions of the current collector 11 of the bipolar electrode 1 are designed to be smaller than the outer shape of each lower resin frame 100L and larger than the dimensions of the opening 104. Therefore, the peripheral edge of the current collector 11 overlaps the inner edge of the opening 104 of the lower resin frame 100L. Although not shown here, the positive electrode 12 and negative electrode 13 of the bipolar electrode 1 are designed to be smaller than the dimensions of the opening 104. The positive electrode 12 and negative electrode 13 are located inside the opening 104 with the current collector 11 and the lower resin frame 100L overlapping.

[0034] The bipolar electrode 1 can be positioned relative to the lower resin frame 100L by, for example, photographing the lower resin frame 100L with an imaging device, detecting the edges of the lower resin frame 100L using known image recognition technology, and adjusting the position of the bipolar electrode 1 to fit the edges. As described above, the lower resin frame 100L is trimmed into a ladder shape, allowing the edges to be accurately detected, improving the positioning accuracy of the bipolar electrode 1. The bipolar electrode 1 is accurately set on the lower resin frame 100L using, for example, a robot.

[0035] Then, while the lower resin frame 100L is being transported, the lower resin frame 100L (lower sealing material 41) and the current collector 11 of the bipolar electrode 1 are bonded together. As shown on the left side of FIG. 4 , for example, by irradiating a laser along a short side in the width direction of the lower resin frame 100L, the short side and the current collector 11 can be welded together. Then, by irradiating a laser along a long side of the lower resin frame 100L, the long side and the current collector 11 can be welded together. In this way, the lower resin frame 100L and the current collector 11 of the bipolar electrode 1 are bonded together along the entire periphery of the current collector 11. Note that the resin frame 100L and the current collector 11 can be bonded together by, for example, heat welding using a known heat roller or heat sealer, or ultrasonic welding.

[0036] Further, a molding step of the upper sealing material 42 is carried out (S202). The upper sealing material 42 has the same configuration as the lower sealing material 41, and can be molded by the method described above with reference to Fig. 3. The plurality of upper sealing materials 42 are formed as a continuous resin frame 100 on the release film 103.

[0037] Next, an upper sealant placement and welding step (S103) is performed, in which an upper sealant 42 is placed and welded onto the lower sealant 41 to which the bipolar electrode 1 has been joined. As shown on the right side of FIG. 4, a continuous upper resin frame 100U that will become the upper sealant 42 is transported in the same direction as the lower resin frame 100L. In this manner, the upper sealant 42 is positioned relative to the bipolar electrode 1 while the lower resin frame 100L and the upper resin frame 100U are being transported in the same direction.

[0038] The upper sealant 42 can be positioned relative to the bipolar electrode 1 by, for example, photographing the lower sealant 41 and the bipolar electrode 1 with an imaging device, detecting the edges using a known image recognition technique, and adjusting the transport speed of the upper resin frame 100U that will become the upper sealant 42. The dimensions of the current collector 11 of the bipolar electrode 1 are designed to be smaller than the outer shape of each upper resin frame 100U and larger than the dimensions of the opening 104. Therefore, the peripheral edge of the current collector 11 overlaps the inner edge of the opening 104 of the upper resin frame 100U. Furthermore, the positive electrode 12 and the negative electrode 13 are positioned inside the opening 104 with the current collector 11 and the upper resin frame 100U overlapping.

[0039] Then, while the lower resin frame 100L and the upper resin frame 100U are being transported in the same direction, the release film 103 of the upper resin frame 100U is peeled off, and then the upper resin frame 100U (upper sealant 42), the current collector 11 of the bipolar electrode 1, and the lower resin frame 100L (lower sealant 41) are bonded together. As shown on the right side of FIG. 4 , for example, a laser beam is irradiated along the long sides of the upper resin frame 100U to weld the long sides to the current collector 11. Then, a laser beam is irradiated along the short sides of the upper resin frame 100U in the width direction to weld the short sides to the current collector 11. As a result, the upper resin frame 100U and the current collector 11 of the bipolar electrode 1 are bonded together around the entire periphery of the current collector 11.

[0040] The release film 103 on the lower resin frame 100L may be peeled off when the lower resin frame 100L and the bipolar electrode 1 are joined together, or when the lower resin frame 100L and the upper resin frame 100U are each joined to the bipolar electrode 1. There is no particular limitation on the timing at which the release film 103 is peeled off.

[0041] Next, a separator placement and welding step (S104) is performed in which separator 2 is placed on and welded to upper sealing material 42. Separators 2 are obtained, for example, by cutting a roll of separator sheet into areas corresponding to individual separators 2. In this embodiment, the dimensions of separator 2 are smaller than the outer shape of resin frame 100 and larger than the dimensions of opening 104. Separator 2 is placed so as to close opening 104, and the area where separator 2 overlaps with upper resin frame 100U is welded. In this way, separator 2 is fixed to upper resin frame 100U.

[0042] Further, a molding step of spacer 43 is carried out (S203). Note that spacer 43 has substantially the same configuration as lower seal material 41 and upper seal material 42, and can be molded by the method described above with reference to Fig. 3. Note that a cutout portion that will become a liquid injection port in a later step is formed in resin frame 100 that will become spacer 43.

[0043] Here, the structure of the resin frame 300 that becomes the spacer 43 will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram illustrating the structure of the resin frame 300 that becomes the spacer 43. FIG. 6 is a diagram illustrating cut portions formed in the resin frame 300. As shown in FIG. 5, similar to the resin frame 100 described above, multiple resin frames 300 are formed into a continuous ladder shape. That is, the continuous resin frame 300 is composed of two straight portions 301 and a connecting portion 302 that connects the straight portions 301. Furthermore, the opening 304 formed by the straight portions 301 and the connecting portion 302 is designed to be smaller than the dimensions of the current collector 11 of the bipolar electrode 1. The opening 304 is designed to be larger than the positive electrode 12 and the negative electrode 13 of the bipolar electrode 1. Therefore, the positive electrode 12 and the negative electrode 13 are disposed inside the opening 304. That is, the two straight portions 301 and the two adjacent connecting portions 302 form a frame that is disposed so as to surround the periphery of the bipolar electrode 1.

[0044] Cut portions 303 are formed in the connecting portions 302. In the example shown in FIGS. 5 and 6 , the cut portions 303 are formed in the connecting portions 302 so as to extend from the inner edge of one opening 304 toward the other adjacent opening 304. The cut portions 303 may be perforations that allow for easy cutting of a predetermined portion of the resin frame 300. For example, a cutter or the like for forming perforations may be used to form the cut portions 303. For example, the cut portions 303 may be formed simultaneously with the trimming process that is performed to form the continuous resin frame 300 into the desired ladder shape as described above.

[0045] Returning to FIG. 2 , a spacer placement and temporary welding process (S105) is then performed, in which a spacer 43 is placed on the separator 2 and temporarily welded. A continuous resin frame 300, which will become the spacer 43, is transported in the same direction as the bipolar electrode 1, which is formed by joining the lower resin frame 100L and the upper resin frame 100U, is transported. While the bipolar electrode 1 and the resin frame 300 are transported in the same direction, the resin frame 300 is positioned relative to the bipolar electrode 1. This positioning can be achieved by adjusting the transport speed of the resin frame 300 using a known image recognition technique. Then, while the bipolar electrode 1 and the resin frame 300 are transported in the same direction, the release film 103 of the resin frame 300 is peeled off, and the upper resin frame 100U is then bonded to the resin frame 300. This results in the continuous formation of an electrode unit consisting of the bipolar electrode 1, separator 2, lower sealant 41, upper sealant 42, and spacer 43.

[0046] 5 shows cutting lines L1 along which the resin frame 300 is cut into individual electrode units in a sheet cutting process (S106) described below. The resin frame 300 is cut along the cutting lines L1 to form the individual spacers 43 shown in FIG. 6. The length of the cut portion 303 is such that it does not reach the outer edge of the spacer 43 when cut along the cutting lines L1. In other words, the length of the cut portion 303 is shorter than the distance from the inner edge to the outer edge of the spacer 43. This makes it possible to prevent leakage when the spacer 43 is bonded to the upper sealing material 42.

[0047] 5 and 6, seven sets of cutting lines are formed. As shown in Fig. 6, a part of the spacer 43 is cut out along one set of cutting lines to form a cutout portion 305 that serves as a liquid injection port in the spacer 43. The liquid injection port is a location where the upper sealing material 42 and the lower sealing material 41 that are adjacent in the stacking direction are not partially joined.

[0048] Next, a sheet cutting step (S106) is performed in which the resin frame 100 is cut into individual electrode units.

[0049] A predetermined gap is formed on the connection portion 102 between the bipolar electrodes 1 on adjacent lower resin frames 100L. No bipolar electrodes 1 are arranged in this gap; only resin material is arranged therein. Individual electrode units are obtained by cutting the resin frame 100 along a cutting line (corresponding to cutting line L1 in FIG. 5) set in the gap in a direction perpendicular to the extension direction of the resin frame 100. A known cutter such as a shear cutter or rotary cutter can be used to cut the resin frame 100.

[0050] Then, a stacking step (S107) is performed in which the cut electrode units are stacked. At this time, a spacer cutting step (S108) is performed in which a predetermined portion of the spacer 43 is cut off using the cutting portion 303 in the uppermost electrode unit for each stacked electrode unit. That is, the stacking step (S107) and the spacer cutting step (S108) are alternately performed repeatedly. This results in an electrode stack 20 having a liquid injection port formed therein. Note that in the stacking step (S107), the spacer 43 of the lower electrode unit and the lower sealing material 41 of the upper electrode unit are welded together. At this time, the unused cut portion 303 of the spacer 43 is melted and joined. This makes it possible to ensure sealing of the portions other than the liquid injection port. Finally, a terminal joining step (S109) is performed in which the positive and negative terminals are connected via the external current collector 5, thereby obtaining a bipolar battery 10.

[0051] As described above, in the embodiment, after the spacer 43 is laminated on the bipolar electrode 1, a liquid injection port can be formed by cutting out a predetermined portion of the spacer 43 using some of the multiple cut portions 303 at the electrode unit stage. This allows the liquid injection ports to be formed in different positions using different cut portions 303 even when manufacturing a bipolar battery having multiple liquid injection ports. This makes it possible to improve the productivity of the bipolar battery 10.

[0052] In the comparative example, resin frames with communication holes formed at different positions are prepared, the number of which corresponds to the number of rows of the liquid injection ports. In this case, there is a problem that the inventory of resin frames with different shapes increases, which increases storage space. In addition, the labor costs for managing such resin frames with different shapes increase.

[0053] In contrast, in the embodiment, it is only necessary to prepare one type of spacer 43 having a cutting portion. This reduces the inventory of unnecessary parts, making it possible to reduce capital investment, space, and personnel costs. Furthermore, compared to the case where spacers of different shapes are transported individually, the spacer 43 of the embodiment can be transported by web handling, making it possible to reduce the number of robots.

[0054] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0055] 1 bipolar electrode 2 Separator 3 Outermost current collector 4 Sealing member 5 External current collector 10 Bipolar Battery 11 Current collector 12 Positive electrode 13 Negative electrode 20 Electrode laminate 31 Positive electrode 41 Lower seal material 42 Upper seal material 43 Spacer 100 Resin Frame 100L Lower Resin Frame 100U upper resin frame 101 Straight section 102 Connection 103 Release film 104 Opening 200 Coating device 201 Coating Department 1 202 Roll 1 203 Roll 2 204 Third Roll 205 2nd Coating Department 206 Roll 4 300 Resin Frame 301 Straight section 302 Connection 303 Cutting section 304 Opening 305 Cutout

Claims

1. a frame portion disposed so as to surround the periphery of the bipolar electrode; a plurality of cuts formed from an inner edge portion of the frame portion toward an outer edge portion thereof, the cuts being shorter than the distance from the inner edge portion to the outer edge portion; Equipped with An annular spacer member arranged on the periphery of adjacent current collectors in the stacking direction of the bipolar battery.

2. The cutting portion is a cutting line that cuts out a predetermined portion of the frame portion. The spacer member according to claim 1 .

3. forming a spacer member including a frame portion arranged to surround a peripheral portion of the bipolar electrode, and a plurality of cut portions formed from an inner edge portion of the frame portion toward an outer edge portion, the cut portions being shorter than the distance from the inner edge portion to the outer edge portion; After laminating the spacer member on the bipolar electrode, a predetermined portion of the frame is cut out using some of the plurality of cutting portions. How to manufacture a bipolar battery.

4. The forming step of the spacer member includes: a step of applying a resin material to form a plurality of continuous frame portions in a ladder shape along the length direction of the strip-shaped release material; forming a cut portion in a connection portion connecting adjacent frame portions such that when the plurality of frame portions are cut into individual pieces, the cut portion is formed from an inner edge portion toward an outer edge portion of the frame portion and is shorter than the distance from the inner edge portion to the outer edge portion; Including, The method for manufacturing the bipolar battery according to claim 3.

5. a plurality of continuous frame portions are transported in the same direction as the transport direction of the bipolar electrode, and the frame portions are stacked on the bipolar electrode; The method for manufacturing the bipolar battery according to claim 4.

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