Method for manufacturing bipolar battery

Abstract

To provide a method for manufacturing a bipolar battery which can appropriately weld a resin member.SOLUTION: A method for manufacturing a bipolar battery includes a manufacturing step of manufacturing bipolar electrode bodies in which seal members are arranged around a rectangular current collector, and a positive electrode layer is arranged on a first surface of the current collector, while a negative electrode layer is arranged on a second surface thereof, a lamination step of laminating the plurality of bipolar electrode bodies through a separator, arranging the spacers between each of the seal members of the bipolar electrode body adjacent to each other in a lamination direction, and thereby obtaining a bipolar electrode laminate, and a welding step of welding the seal members and the spacers aligned in the lamination direction, and forming a frame-like member for sealing the whole circumference of the side face of the bipolar electrode laminate. In the welding step, a welding region is constrained in the lamination direction using a constraint member, and a non-welding region is cooled using a cooling member arranged so as to be brought into close contact with the inner side of the constraint member when being viewed in the lamination direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] This application relates to a method for manufacturing a bipolar battery. [Background technology]

[0002] Patent Documents 1 and 2 disclose a bipolar battery including a bipolar electrode stack in which a plurality of bipolar electrode bodies are stacked, and a frame-shaped member that seals the entire periphery of the side surface of the bipolar electrode stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-78003 A [Patent Document 2] JP 2023-46589 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the batteries disclosed in Patent Documents 1 and 2, the current collector is made of a rectangular metal foil, and a frame-shaped member made of resin is provided on the periphery of the current collector. In such batteries, in the welding process for forming the frame-shaped member, sheet-shaped resin members arranged in the stacking direction are welded. Normally, the amount of resin material is set to a minimum in order to increase the battery capacity. Therefore, the area where the resin material is welded (welding area) is also set to a minimum. However, there is a problem that the welding amount varies in the stacking direction, so in order to prevent sealing failure due to insufficient welding, the heating strength of the resin was increased and welding was performed. However, the resin placed at both ends in the stacking direction in particular became overheated, and a new problem arose in which the heat was transferred to the electrode coating film.

[0005] In view of the above-mentioned circumstances, a main object of the present disclosure is to provide a manufacturing method for a bipolar battery that can appropriately weld resin members. [Means for solving the problem]

[0006] The present disclosure provides at least the following aspects.

[0007] The first aspect is a manufacturing method for a bipolar battery including a bipolar electrode laminate in which a plurality of bipolar electrode bodies are laminated, and a frame-shaped member that seals the entire periphery of the side surface of the bipolar electrode laminate, the manufacturing method including a manufacturing step of manufacturing a bipolar electrode body in which a sealing member is disposed around a rectangular current collector, and a positive electrode layer is disposed on a first surface of the current collector, and a negative electrode layer is disposed on a second surface of the current collector, and a stacking step of stacking a plurality of bipolar electrode bodies via separators, and disposing spacers between the sealing members of adjacent bipolar electrode bodies in the stacking direction to obtain a bipolar electrode laminate. and a welding process for welding sealing members and spacers arranged in the stacking direction to form a frame-shaped member that seals the entire periphery of the side of the bipolar electrode stack, in which the bipolar electrode stack has welded regions where the sealing members and spacers are welded and non-welded regions where the sealing members and spacers are not welded, and in the welding process, the welded regions are restrained in the stacking direction using a restraining member, and the non-welded regions are cooled using a cooling member arranged closer to and on the inside than the restraining member when viewed in the stacking direction.

[0008] A second aspect is the manufacturing method according to the first aspect, wherein the temperature of the cooling member is equal to or lower than the melting points of the sealing member and the spacer.

[0009] A third aspect is the manufacturing method according to the first or second aspect, in which the cooling member is disposed 1 mm or more away from the outer edge of the current collector when viewed in the stacking direction.

[0010] A fourth aspect is a manufacturing method according to any one of the first to third aspects, in which the restraining member and the cooling member have a structure capable of adjusting the temperature by circulating liquid therethrough, and in the welding process, a liquid having a temperature of 20°C or more and 60°C or less circulates through the restraining member, and a liquid having a temperature of 5°C or more and 25°C or less circulates through the cooling member. Effect of the Invention

[0011] According to the manufacturing method of the bipolar battery disclosed herein, the sealing member and the spacer can be appropriately welded. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a plan view of the bipolar electrode body 10. [Diagram 2] FIG. 2 is a cross-sectional view of the bipolar electrode body 10. [Diagram 3] 1 is a cross-sectional view of a bipolar electrode laminate 50 obtained in a lamination step S2. [Figure 4] 1 is a cross-sectional view focusing on one side surface 51 of the bipolar electrode stack 50 in a welding step S3. [Diagram 5] FIG. 5 is a cross-sectional view focusing on one side surface 51 of a bipolar electrode stack 50 in a conventional welding process, and corresponds to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The manufacturing method of the bipolar battery of the present disclosure will be described using one embodiment.

[0014] One embodiment is a method for manufacturing a bipolar battery including a bipolar electrode laminate in which a plurality of bipolar electrode bodies are laminated, and a frame-shaped member that seals the entire periphery of the side surface of the bipolar electrode laminate. The method includes a fabrication step S1, a lamination step S2, and a welding step S3. Each step will be described below.

[0015] <Production process S1> The fabrication process S1 is a process for fabricating a bipolar electrode body 10 in which a sealing member 14 is disposed around a rectangular current collector 11, a positive electrode layer 12 is disposed on a first surface 11a of the current collector 11, and a negative electrode layer 13 is disposed on a second surface 11b of the current collector 11. A plan view of the bipolar electrode body 10 is shown in Fig. 1. A cross-sectional view of the bipolar electrode body 10 is shown in Fig. 2.

[0016] (Current collector 11) The current collector 11 is a rectangular sheet-like conductive member in a plan view. The current collector 11 has a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The current collector 11 is made of, for example, a metal foil or an alloy foil. Examples of the metal foil include copper foil, aluminum foil, titanium foil, and nickel foil. Examples of the alloy foil include stainless steel foil, plated steel sheet, and plated stainless steel sheet. The alloy foil may be an alloy foil of the metals exemplified as the material of the metal foil. The current collector 11 may be formed by integrating or laminating a plurality of metal foils, or may be formed by plating the surface of a metal foil with another metal.

[0017] (Positive electrode layer 12) The positive electrode layer 12 is a rectangular sheet-like member in a plan view, and is disposed on the first surface 11a of the current collector 11. The positive electrode layer 12 includes a positive electrode active material. Examples of the positive electrode active material include a composite oxide, metallic lithium, and sulfur. The composition of the composite oxide includes, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum, and lithium. Examples of the composite oxide include olivine-type lithium iron phosphate (LiFePO4), LiCoO2, and LiNiMnCoO2.

[0018] The positive electrode layer 12 may contain a conductive additive. Examples of the conductive additive include acetylene black, carbon black, and graphite.

[0019] The positive electrode layer 12 may contain a binder. Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluorine rubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins, acrylic resins containing monomer units such as acrylic acid and methacrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, alginates such as sodium alginate and ammonium alginate, water-soluble cellulose ester crosslinked bodies, and starch-acrylic acid graft polymers.

[0020] The method of forming the positive electrode layer 12 on the first surface 11a of the current collector 11 is not particularly limited, and a known method may be appropriately adopted. For example, a roll coating method, a die coating method, a dip coating method, a doctor blade method, a spray coating method, a curtain coating method, etc. may be mentioned. Specifically, the material constituting the positive electrode layer 12 is mixed with a solvent to obtain a slurry, and then the slurry is applied to the first surface 11a of the current collector 11 and dried to obtain the positive electrode layer 12. The solvent is, for example, N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, or water. In order to increase the electrode density, the positive electrode layer 12 after drying may be compressed.

[0021] (Negative electrode layer 13) The negative electrode layer 13 is a rectangular sheet-like member in a plan view, and is disposed on the second surface 11b of the current collector 11. The negative electrode layer 13 includes a negative electrode active material. Examples of the negative electrode active material include carbon such as graphite, artificial graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, and soft carbon, metal compounds, elements capable of forming an alloy with lithium or compounds of such elements, and boron-added carbon. Examples of elements capable of forming an alloy with lithium include silicon and tin.

[0022] The negative electrode layer 13 may contain a conductive assistant. The conductive assistant may be appropriately selected from those applicable to the positive electrode layer 12. The negative electrode layer 13 may also contain a binder. The binder may be appropriately selected from those applicable to the positive electrode active material layer 12.

[0023] The method for forming the negative electrode layer 13 on the second surface 11b of the current collector 11 is not particularly limited, and any known method may be appropriately adopted. For example, the method may be appropriately selected from those exemplified as the method for forming the positive electrode layer 12.

[0024] (Sealing member 14) The sealing member 14 is a rectangular frame-shaped member disposed around the current collector 11 in a plan view. As shown in Fig. 1 and Fig. 2, the sealing member 14 is disposed at a position spaced apart from the positive electrode layer 12 and the negative electrode layer 13. The sealing member 14 includes a first sealing member 14a disposed on the first surface 11a of the current collector 11 and a second sealing member 14b disposed on the second surface 11b of the current collector 11.

[0025] The first seal member 14a is a rectangular frame-shaped member that is disposed along the periphery of the first surface 11a of the current collector 11 and is joined to the first surface 11a. The outer edge of the first seal member 14a is larger than the outer edge of the current collector 11, and the inner edge of the first seal member 14a is smaller than the outer edge of the current collector 11. In addition, in a plan view, the inner edge of the first seal member 14a is separated from the positive electrode layer 12. The first seal member 14a and the current collector 11 are joined in a region where they overlap each other in a plan view.

[0026] The second seal member 14b is different from the first seal member 14a in that it is disposed on the second surface 11b of the current collector 11, but otherwise has the same configuration as the first seal member 14a. That is, the second seal member 14b is a rectangular frame-shaped member, disposed along the periphery of the second surface 11b of the current collector 11, and bonded to the second surface 11b. As shown in FIG. 2, the outer edge of the second seal member 14b is larger than the outer edge of the current collector 11, and the inner edge of the second seal member 14b is smaller than the outer edge of the current collector 11. In addition, in a plan view, the inner edge of the second seal member 14b is separated from the negative electrode layer 13. The second seal member 14b and the current collector 11 are bonded in a region where they overlap each other in a plan view. The first seal member 14a and the second seal member 14b may be bonded in a region where they contact each other.

[0027] The first seal member 14a and the second seal member 14b are made of a resin material having electrolyte resistance, such as acid-modified polyethylene (acid-modified PE), acid-modified polypropylene (acid-modified PP), polyethylene, polypropylene, etc. The first seal member 14a and the second seal member 14b may be made of the same material or different materials.

[0028] The above describes the manufacturing process S1 of the bipolar electrode body 10. In the bipolar electrode stack 50 described below, a positive electrode terminal electrode body 21 and a negative electrode terminal electrode body 22 arranged at the ends in the stacking direction are used. Therefore, the positive electrode terminal electrode body 21 and the negative electrode terminal electrode body 22 may be manufactured in the manufacturing process. The positive electrode terminal electrode body 21 is the bipolar electrode body 10 without the negative electrode layer 13. The negative electrode terminal electrode body 22 is the bipolar electrode body 10 without the positive electrode layer 12.

[0029] <Lamination process S2> The lamination step S2 is a step of laminating a plurality of bipolar electrode bodies 10 with separators 30 interposed therebetween, and arranging spacers 40 between the sealing members 14 of the bipolar electrode bodies 10 adjacent in the lamination direction, to obtain a bipolar electrode laminate 50. Fig. 3 shows a cross-sectional view of the bipolar electrode laminate 50 obtained by the lamination step S2.

[0030] (Separator 30) The separators 30 are sheet-like members and are disposed between the bipolar electrode bodies 10. Specifically, they are disposed between the electrode layers (positive electrode layer 12 and negative electrode layer 13) of the bipolar electrode bodies 10 adjacent in the stacking direction. The separators 30 are, for example, porous sheets or nonwoven fabrics containing a polymer that absorbs and retains an electrolyte. Examples of materials constituting the separators 30 include polypropylene, polyethylene, polyolefin, and polyester. The separators 30 may have a single-layer structure or a multi-layer structure.

[0031] In a bipolar battery, the separator 30 is used in a state in which it is impregnated with an electrolyte. The electrolyte impregnated in the separator 30 may be, for example, an electrolyte containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The electrolyte salt may be, for example, a lithium salt such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, or LiN(CF3SO2)2. The non-aqueous solvent may be, for example, a cyclic carbonate, a cyclic ester, a chain carbonate, a chain ester, or an ether. The electrolyte is injected into the space S after the welding step S3. This will be described in detail later.

[0032] (Spacer 40) The spacers 40 are rectangular frame-shaped members disposed between the bipolar electrode bodies 10. Specifically, the spacers 40 are disposed between the seal members 14 of the bipolar electrode bodies 10 adjacent in the stacking direction. More specifically, the spacers 40 are disposed between the first seal member 14a of one bipolar electrode body 10 and the second seal member 14b of the other bipolar electrode body 10 in the bipolar electrode bodies 10 adjacent in the stacking direction.

[0033] When viewed in the stacking direction, the outer edge of the spacer 40 coincides with the outer edge of the seal member 14 (first seal member 14a and second seal member 14b), while the inner edge of the spacer 40 is located outside the inner edge of the seal member 14. For example, the distance between the inner edge of the spacer 40 and the inner edge of the seal member 14 may be 1 mm or more. Then, in a welding step S3 described later, the portions where the seal member 14 and the spacer 40 come into contact with each other are welded.

[0034] The spacer 40 may be an integrally formed rectangular frame member, or may be a rectangular frame member formed by using strip-shaped members and arranging the ends of each member so as to overlap each other.

[0035] The spacer 40 is made of an electrolyte-resistant resin material such as acid-modified polyethylene (acid-modified PE), acid-modified polypropylene (acid-modified PP), polyethylene, or polypropylene, similar to the seal member 14. However, the spacer 40 may be made of the same material as the first seal member 14a and the second seal member 14b, or may be made of a different material.

[0036] (Layering method) The lamination method will be further described. First, a plurality of bipolar electrode bodies 10 are laminated via a separator. At this time, the bipolar electrode bodies 10 adjacent in the lamination direction are laminated so that the positive electrode layer 12 of one bipolar electrode body 10 faces the negative electrode layer 13 of the other bipolar electrode body 10. The separator 30 is disposed between these positive electrode layers 12 and negative electrode layers 13. In addition, a positive electrode terminal electrode body 21 is disposed at one end of the lamination direction of the bipolar electrode laminate 50, and a negative electrode terminal electrode body 22 is disposed at the other end. Furthermore, when laminating the bipolar electrode bodies 10, a spacer 40 is disposed between the sealing members 14 of the bipolar electrode bodies 10 adjacent in the lamination direction. As a result, the sealing members 14 and the spacers 40 are disposed alternately on each side of the bipolar electrode laminate 50.

[0037] <Welding process S3> The welding process S3 is a process of welding the seal members 14 and the spacers 40 aligned in the stacking direction to form a frame-shaped member that seals the entire periphery of the side surface of the bipolar electrode stack 50. The frame-shaped member is a member in which the seal members 14 and the spacers 40 are integrated by welding.

[0038] The method of welding the seal member 14 and the spacer 40 is not particularly limited, and may be any method that heats each side surface of the bipolar electrode stack 50. The type of heat source for heating each side surface of the bipolar electrode stack 50 is not particularly limited, but may be, for example, an IR heater.

[0039] FIG. 4 shows a cross-sectional view of one side surface 51 of the bipolar electrode laminate 50. As shown in FIG. 4, in the bipolar electrode laminate 50, a welding region R1 where the seal member 14 and the spacer 40 are welded, and a non-welding region R2 where the seal member 14 and the spacer 40 are not welded are set. Both the welding region R1 and the non-welding region R2 are set along the stacking direction. The welding region R1 is a region where the seal member 14 and the spacer 40 are welded, and is set in a predetermined range including the outer edge of the bipolar electrode laminate 50 as viewed in the stacking direction. The range of the welding region R1 is not particularly limited, but from the viewpoint of appropriately welding the seal member 14 and the spacer 40 and imparting to the formed frame-shaped member appropriate rigidity capable of withstanding expansion and contraction accompanying charging and discharging of the battery, it may be set to a range of 1 mm to 20 mm from the outer edge of the bipolar electrode laminate 50 toward the inside as viewed in the stacking direction (see L1 in FIG. 4). The non-welded region R2 is a region that is disposed from the outer edge of the current collector 11 to the inner edge of the welded region R1 when viewed in the stacking direction. The range of the non-welded region R2 is not particularly limited, but from the viewpoint of suppressing deterioration of the electrode layers (particularly deterioration and decomposition of the binder) and oxidation of the current collector 11 caused by heat transfer during welding to the electrode layers (positive electrode layer 12 and negative electrode layer 13) and the current collector 11, the length from the outer edge of the current collector 10 to the inner edge of the welded region R1 when viewed in the stacking direction may be set to 1 mm or more and 20 mm or less (see L2 in FIG. 4).

[0040] With the welded region R1 and the non-welded region R2 set in this manner, the welding step S3 is carried out. In the welding step S3, as shown in Fig. 4, the welded region R1 is restrained in the stacking direction using restraining members 60, 60, and the non-welded region R2 is cooled using cooling members 70, 70 arranged closer to the inside of the restraining members 60, 60 as viewed in the stacking direction. This allows the seal member 14 and the spacer 40 to be appropriately welded in the welded region R1 while stably controlling the seal member 14 and the spacer 40 not to be welded in the non-welded region R2. This will be described in detail below.

[0041] FIG. 5 is a diagram showing a conventional welding process, and corresponds to FIG. 4. As shown in FIG. 5, in the conventional welding process, the sealing member 14 and the spacer 40 are restrained in the stacking direction by using restraining members 60, 60. Then, the side surface 51 of the bipolar electrode laminate 50 is heated by a predetermined heat source to weld the sealing member 14 and the spacer 40. In this case, the heat source heats the bipolar electrode laminate 50 from the side surface 51, so that the vicinity of the side surface 51 and the upper and lower layers that come into contact with the surface in the stacking direction are directly heated by the heat source. Therefore, although the sealing member 14 and the spacer 40 can be appropriately welded in these parts, there is a problem that heat is not sufficiently transmitted to the inside of the resin layer (the region indicated by R3 in FIG. 4), which makes the welding unstable, that is, the welding allowance varies in the stacking direction. Furthermore, if welding is performed by increasing the heating intensity on the resin layer in order to prevent poor sealing due to insufficient welding, the sealing members 14 and the spacers 40 arranged at both ends in the stacking direction may be overheated, the welding area may expand, and the heat may be transmitted to the electrode layer (R3 in FIG. 5).

[0042] In contrast, one embodiment is characterized in that the welding step S3 is further performed using cooling members 70, 70. By using the cooling members 70, 70, the upper and lower layers in the welding region R1 can be actively cooled, so that the side surface 51 can be heated so that heat is sufficiently transmitted to the inside of the welding region R1, and a stable resin penetration depth can be obtained. That is, the entire welding region R1 can be appropriately welded. In addition, the cooling members 70, 70 can suppress welding of the non-welded region R2. Therefore, according to the welding step S3 of one embodiment, it is possible to stably control the sealing member 14 and the spacer 40 in the welding region R1 to be appropriately welded, while not welding the sealing member 14 and the spacer 40 in the non-welded region R2.

[0043] The restraining members 60, 60 are members that restrain the welded region R1 in the stacking direction, and are therefore arranged in the upper and lower layers of the welded region R1. The restraining members 60, 60 may simply be members that restrain the welded region R1, but may further have a mechanism for adjusting the temperature of the restraining members 60, 60 to promote welding. For example, the restraining members 60, 60 may have a structure that allows liquid to flow inside them and can adjust the temperature. The type of liquid is not particularly limited, but is, for example, water (hot water). The temperature of the liquid may be set appropriately depending on the purpose, and is, for example, 20°C or higher and 60°C or lower. Therefore, in the welding step S3, a liquid with a temperature of 20°C or higher and 60°C or lower may flow inside the restraining members 60, 60.

[0044] The cooling members 70, 70 are arranged closer to the inside than the restraining members 60, 60 when viewed in the stacking direction, and are members that cool the non-welded region R2. That is, the cooling members 70, 70 are arranged in the upper and lower layers of the non-welded region R2. "Close" means that the distance between the cooling members 70, 70 and the restraining members 60, 60 is within 5 mm. The cooling members 70, 70 may be arranged in contact with the restraining members 60, 60. In addition, the cooling members 70, 70 may be arranged 1 mm or more away from the outer edge of the current collector 11 when viewed in the stacking direction, from the viewpoint of suppressing heat transfer to the electrode layer and the current collector 11. The cooling members 70, 70 may restrain the seal member 14 and the spacer 40 in the stacking direction, similar to the restraining members 60, 60. The temperature of the cooling members 70, 70 is not particularly limited, but may be lower than the melting point of the seal member 14 material and the spacer 40 from the viewpoint of promoting cooling. The cooling members 70, 70 may have a structure capable of adjusting the temperature by circulating a liquid therein. The type of liquid is not particularly limited, but may be water (cold water), for example. The temperature of the liquid may be set appropriately depending on the purpose, but is, for example, 5°C or higher and 25°C or lower. Therefore, in the welding step S3, a liquid having a temperature of 5°C or higher and 25°C or lower may be circulating inside the cooling members 70, 70.

[0045] 4, the restraining members 60, 60 and the cooling members 70, 70 are illustrated as separate members, but are not limited to this. For example, the restraining members and the cooling members may be integrated.

[0046] In the welding process S3, the seal members 14 and the spacers 40 on each side are welded, and a frame-shaped member is formed over the entire side of the bipolar electrode stack 50. By forming the frame-shaped member, a space S is formed inside the bipolar electrode stack 50. Specifically, a space S is formed between the bipolar electrodes 10, between the positive electrode terminal electrode body 21 and the bipolar electrode body 10, and between the negative electrode terminal electrode body 22 and the bipolar electrode body 10. Since the space S is for storing the electrolyte, the space S is sealed by the frame-shaped member so that the electrolyte does not leak from the space S.

[0047] The electrolyte is injected into the space S after the welding step S3. The method of injecting the electrolyte is not particularly limited, but for example, by sandwiching a predetermined insert between the seal member 14 and the spacer and performing the welding step S3, an inlet through which the electrolyte can be injected can be formed. Then, after the electrolyte is injected into the space S from the inlet, the inlet is blocked by heating, thereby preventing the electrolyte from leaking from the space S.

[0048] The manufacturing method of the bipolar battery according to the present disclosure has been described above using one embodiment. According to the manufacturing method of the bipolar battery according to the present disclosure, the sealing member and the spacer can be appropriately welded. [Explanation of symbols]

[0049] 10 Bipolar electrode body 11 Current collector 12 Positive electrode layer 13 Negative electrode layer 14 Sealing material 14a First seal member 14b Second seal member 21 Positive terminal electrode body 22 Negative terminal electrode body 30 Separator 40 Spacer 50 Bipolar electrode stack 60 Restraint member 70 Cooling material

Claims

1. A method for manufacturing a bipolar battery comprising a bipolar electrode stack in which a plurality of bipolar electrode bodies are stacked, and a frame-shaped member that seals an entire periphery of a side surface of the bipolar electrode stack, comprising: a fabrication step of fabricating a bipolar electrode body in which a sealing member is disposed around a rectangular current collector, and a positive electrode layer is disposed on a first surface of the current collector and a negative electrode layer is disposed on a second surface of the current collector; a stacking step of stacking a plurality of the bipolar electrode bodies with separators interposed therebetween and disposing spacers between the sealing members of the bipolar electrode bodies adjacent in a stacking direction to obtain the bipolar electrode stack; a welding process of welding the sealing members and the spacers arranged in a stacking direction to form the frame-shaped member that seals the entire periphery of the side surface of the bipolar electrode stack, In the bipolar electrode stack, a welding region where the sealing member and the spacer are welded and a non-welding region where the sealing member and the spacer are not welded are set, In the welding step, the welding region is restrained in the stacking direction by using a restraining member, and the non-welded region is cooled by using a cooling member disposed closer to the inside than the restraining member when viewed in the stacking direction. How to manufacture a bipolar battery.

2. The manufacturing method according to claim 1 , wherein the temperature of the cooling member is equal to or lower than the melting points of the sealing member and the spacer.

3. The manufacturing method according to claim 1 , wherein the cooling member is disposed 1 mm or more away from an outer edge of the current collector when viewed in the stacking direction.

4. the restraining member and the cooling member have a structure capable of adjusting temperature by circulating liquid therethrough, In the welding step, a liquid having a temperature of 20° C. or more and 60° C. or less flows through the inside of the restraint member, and a liquid having a temperature of 5° C. or more and 25° C. or less flows through the inside of the cooling member. The method according to claim 1 or 2.

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