Battery manufacturing method

Abstract

To provide a battery manufacturing method that simplifies production management.SOLUTION: A battery manufacturing method includes a preparation step of preparing an electrode member having a current collector 1 and composite layers 2A, 2B formed on a first surface of the current collector in the thickness direction, and an electrode production step including a first sealing step of heat-welding a first resin sheet 11A arranged on the first surface and having two slit portions S formed therein, and a second resin sheet 11B arranged on a second surface of the current collector opposing the first surface to cover an outer edge portion of the current collector, a separator lamination step of heat-welding a separator 12 to the first resin sheet and laminating it on the electrode member, a terminal joining step of folding a folding portion F of the first resin sheet, which has become bendable in the thickness direction due to the slit portions, to expose the current collector and joining the exposed current collector to a terminal 13, and a second sealing step of heat-welding the folding portion to fill the slit portion to obtain an electrode.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a battery. [Background technology]

[0002] Information-related devices and communication devices such as personal computers, video cameras, and mobile phones are becoming widespread. In addition, from the perspective of reducing the burden on the environment, automobiles using motors such as electric vehicles are becoming more and more popular. Accordingly, various studies are being conducted on the batteries used as the power source for these devices.

[0003] For example, Patent Document 1 discloses an electricity storage device equipped with a voltage detection line. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-036303 A Summary of the Invention [Problem to be solved by the invention]

[0005] From the viewpoint of production management, simplification of management in a battery manufacturing method is required. The present disclosure has been made in view of the above-mentioned circumstances, and has a main object to provide a battery manufacturing method that enables simplification of production management. [Means for solving the problem]

[0006] [1] an electrode preparation step of preparing an electrode; A method for producing a battery, comprising: a lamination step of obtaining an electrode laminate using the electrode, The electrode preparation process includes: a preparation process for preparing an electrode member having a current collector and a composite layer formed on a first surface of the current collector in a thickness direction; a first sealing process in which a first resin sheet, which is disposed on the first surface and has two slit portions formed therein, and a second resin sheet, which is disposed on a second surface of the current collector opposite to the first surface, are thermally welded to each other to cover an outer edge portion of the current collector; a separator lamination process for laminating a separator on the electrode member by thermally welding the separator to the first resin sheet; a terminal joining process in which the folding portion of the first resin sheet, which has been made bendable in the thickness direction by the slit portion, is folded to expose the current collector, and the exposed current collector and a terminal are joined; and a second sealing process of thermally welding the folded portion to fill the slit portion and obtain the electrode.

[0007] [2] The method for manufacturing a battery according to [1], wherein the second sealing step is performed using an impulse machine.

[0008] [3] In the preparation process, a plurality of the electrode members are prepared, the plurality of electrode members after the first sealing process are cross-linked by the first resin sheet and the second resin sheet, The method for manufacturing a battery according to [1] or [2], further comprising a sheet-by-sheet process, in which the first resin sheet and the second resin sheet are cut at bridged portions after the separator lamination process and before the terminal joining process, to separate the plurality of electrode members into sheets.

[0009] [4] The method for producing a battery according to any one of [1] to [3], wherein the electrode is a bipolar electrode having a positive electrode active material layer, the current collector, and a negative electrode active material layer in this order in the thickness direction.

[0010] [5] The method for manufacturing a battery described in any one of [1] to [4], wherein, in the separator lamination process, the first resin sheet and the separator are heat-welded at an edge of the first resin sheet extending in a direction perpendicular to an extending direction of the edge of the first resin sheet in which the slit portion is formed. Effect of the Invention

[0011] The present disclosure provides an advantage in that production management in a battery manufacturing method can be simplified. [Brief description of the drawings]

[0012] [Figure 1] 1A to 1C are diagrams illustrating a conventional procedure for joining terminals. [Diagram 2] 11A and 11B are diagrams illustrating an electrode member in a preparation process. [Diagram 3] FIG. 4 is a diagram illustrating a first sealing process. [Figure 4] FIG. 1 is a diagram illustrating a separator lamination process. [Diagram 5] 1A to 1C are diagrams illustrating a terminal joining process. [Figure 6] FIG. 11 is a diagram illustrating a second sealing process. [Figure 7] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The manufacturing method of the battery in the present disclosure will be described in detail below with reference to the drawings. Each of the drawings shown below is a schematic illustration, and the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, in this specification, when expressing an aspect in which another member is arranged relative to a certain member, the term "above" or "below" is used, unless otherwise specified, it includes both a case in which another member is arranged directly above or below a certain member so as to be in contact with the certain member, and a case in which another member is arranged above or below a certain member via another member. In addition, in this disclosure, "terminal" means a terminal for voltage detection unless otherwise specified.

[0014] The method for manufacturing a battery according to the present disclosure includes an electrode fabrication step of fabricating an electrode, and a lamination step of obtaining an electrode laminate using the electrode. The electrode fabrication step includes a predetermined preparation process, a first sealing process, a separator lamination process, a terminal joining process, and a second sealing process.

[0015] According to the present disclosure, a slit portion is formed in the first sealing process, and the folding portion of the first resin sheet, which can be folded in the thickness direction by the slit portion, is folded to expose the current collector and then the exposed current collector is joined to a terminal, thereby simplifying production management in the battery manufacturing method.

[0016] FIG. 1 is a schematic perspective view illustrating a conventional procedure for joining terminals. As shown in FIGS. 1(a) and 1(b), in the past, after joining a terminal 13 to a current collector 1, the outer edge of the current collector 1 was sealed together with the terminal 13 by thermal welding of resin sheets (first resin sheet 11A and second resin sheet 11B). In other words, the seal welding was performed after the terminal joining. On the other hand, in such a procedure, the terminal part and the part other than the terminal at the outer edge of the current collector must be seal welded together, which requires the management of the seal welding to be performed in a lump, and there is a concern that production management may be difficult. In addition, in such a procedure, for example, when a large number of electrodes are produced by web transportation, there is a concern that complicated work is required. In addition, there are restrictions on the process order, such as the difficulty of joining the terminal after sealing the outer edge, and the flexibility of changing the process order is low.

[0017] In contrast, in the manufacturing method of the battery in the present disclosure, as shown in Figs. 5 and 6 described later, the first resin sheet and the second resin sheet are thermally welded to the current collector, and then the current collector is exposed by folding the folding part that can be folded in the thickness direction by the slit part provided in the first resin sheet, and the exposed current collector is joined to the terminal, and then the first resin sheet and the second resin sheet are thermally welded to the current collector again. With such a procedure, the terminal part of the current collector and the part other than the terminal can be individually sealed and welded, so that the sealing and welding can be managed individually, and production management is simplified. In addition, the above procedure is more flexible in changing the process order than the conventional one, and production costs can be reduced.

[0018] 1. Electrode preparation process The electrode preparation process is a process for preparing electrodes, and includes a predetermined preparation process, a first sealing process, a separator lamination process, a terminal joining process, and a second sealing process.

[0019] (1) Preparation FIG. 2(a) is a schematic plan view of an electrode member prepared in the preparation process, as viewed in a thickness direction DT, and FIG. 2(b) is a cross-sectional view taken along line AA of FIG. 2(a).

[0020] As shown in Figures 2(a) and (b), in the preparation process, an electrode member 10 is prepared, which includes a current collector 1 and a composite layer 2 (2A) formed on a first surface p of the current collector 1 in the thickness direction DT. As shown in Figure 2(b), the composite layer may also be formed on a second surface q of the current collector 1 facing the first surface p (composite layer 2B). Note that in the preparation process, one or more electrodes may be prepared.

[0021] The current collector may be a member that functions as a positive electrode current collector, a member that functions as a negative electrode current collector, or a member that functions as both. In other words, the electrode member may be a positive electrode member, a negative electrode member, or a bipolar member. Examples of the material of the current collector include metals such as aluminum, copper, SUS, and nickel. Examples of the shape of the current collector include a foil shape and a mesh shape.

[0022] The mixture layer contains at least an active material, and may contain at least one of a conductive assistant and a binder, if necessary.

[0023] The composite layer may be a positive electrode active material layer or a negative electrode active material layer. When the composite layer is a positive electrode active material layer, the active material (positive electrode active material) may be, for example, an oxide active material. For example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 Rock salt layered active materials such as LiMn 2 O 4 Spinel-type active materials such as LiFePO 4 Examples of the positive electrode active material include olivine type active materials such as those mentioned above. Sulfur (S) may also be used as the positive electrode active material. The positive electrode active material may be in the form of particles, for example.

[0024] When the composite layer is a negative electrode active material layer, examples of the active material (negative electrode active material) include Li-based active materials such as metallic lithium and lithium alloys; carbon-based active materials such as graphite, hard carbon and soft carbon; oxide-based active materials such as lithium titanate; and Si-based active materials such as simple Si, Si alloys and Si oxides.

[0025] Examples of the conductive assistant include carbon materials. Examples of the carbon materials include particulate carbon materials such as acetylene black (AB) and ketjen black (KB), and fibrous carbon materials such as carbon fiber, carbon nanotube (CNT), and carbon nanofiber (CNF). Examples of the binder include rubber-based binders such as butadiene rubber (BR), and fluorine-containing binders such as polyvinylidene fluoride (PVDF). The thickness of the composite layer is, for example, 0.1 μm or more and 1000 μm or less.

[0026] The planar shape of the electrode member is not particularly limited, but is preferably a rectangle having long sides extending in a first direction and short sides extending in a second direction perpendicular to the first direction.

[0027] (2) First sealing treatment The first sealing process will be described with reference to Fig. 3. Fig. 3(a) is a schematic plan view of the electrode member after the first sealing process, as viewed from the first resin sheet side. Fig. 3(b) is a schematic cross-sectional view of Fig. 3(a) cut at the slit portion. Fig. 3(c) is a schematic perspective view of the vicinity of the slit portion. Fig. 3(d) is a schematic plan view illustrating the electrode member after the first sealing process.

[0028] 3(a) to 3(c), the first sealing process is a process for thermally welding a first resin sheet 11A, which is disposed on a first surface p and has two slit portions S formed therein, to a second resin sheet 11B, which is disposed on a second surface q of the current collector 1 opposite the first surface p, to cover the outer edge of the current collector 1. The outer edge of the current collector refers to a portion including the outer edge O of the current collector 1, as shown in FIG. 3(b).

[0029] As shown in Fig. 3(a), the two slits S are preferably formed on the side (edge) of the resin sheet 11A extending in the second direction D2 of the electrode member. The slits S usually extend in a direction (first direction) perpendicular to the extension direction (second direction) of the side of the first resin sheet in which the slits are formed. The distance between the slits is not particularly limited and can be adjusted as appropriate.

[0030] 3(b) and (c), the heat-sealed portion in the first sealing process (first heat-sealed portion H1) usually does not include the portion between the two slit portions S, and the first resin sheet 11A is not heat-sealed to the current collector 1 and the second resin sheet 11B in the above-mentioned portion. This is because the above-mentioned portion becomes a folding portion described later.

[0031] The conditions such as the heating temperature in the first sealing treatment are not particularly limited as long as the first resin sheet and the second resin sheet can be thermally welded to the current collector and the other resin sheet.

[0032] The material of the first resin sheet and the second resin sheet is preferably a thermoplastic resin. Examples of the thermoplastic resin include fluorine-based resins such as polytetrafluoroethylene (PTFE), and olefin-based resins such as polyethylene (PE) and polypropylene. The thickness of the first resin sheet and the second resin sheet is not particularly limited, and is, for example, 10 μm or more and 100 μm or less.

[0033] Furthermore, as shown in FIG. 3(d), when multiple electrode members are prepared in the above preparation step, after the first sealing process, the multiple electrode members (10A, 10B) may be cross-linked by a first resin sheet and a second resin sheet (not shown).

[0034] (3) Separator lamination process The separator lamination process will be described with reference to Fig. 4. Fig. 4(a) is a schematic plan view of the separator lamination process as seen from the first resin sheet side, and Fig. 4(b) is a cross-sectional view taken along line AA of Fig. 4(a).

[0035] In the separator lamination process, the separator 12 is thermally welded to the first resin sheet 11A and laminated on the electrode member 10. As shown in FIG. 4(a), it is preferable that the separator 12 and the slit portion S do not overlap each other.

[0036] The method of thermal welding is not particularly limited, but an example of the method is heating and welding with a laser L irradiated from a laser head 30. The type of laser is not particularly limited, but for example, CO 2 Examples of lasers include gas lasers such as lasers.

[0037] Furthermore, as shown in FIG. 4(a), it is preferable that the first resin sheet 11A and the separator 12 are thermally welded together at an edge of the first resin sheet 11A extending in a direction (first direction D1) perpendicular to the extending direction (second direction D2) of the edge of the first resin sheet 11A in which the slit portion S is formed.

[0038] The material of the separator is not particularly limited as long as it is a porous film, and examples of the material include resins such as polyethylene (PE), etc. The thickness of the separator is, for example, 0.1 μm or more and 1000 μm or less.

[0039] Here, as shown in FIG. 3(d), when multiple electrode members are cross-linked, the electrode preparation process may include a sheet-by-sheet process, which is performed after the separator lamination process and before the terminal joining process described later, in which the first resin sheet and the second resin sheet are cut at the cross-linked portions to separate multiple electrode members.

[0040] (4) Terminal connection processing The terminal joining process will be described with reference to Fig. 5. Fig. 5(a) is a schematic plan view of an electrode member with a separator laminated thereon, as viewed from the first resin sheet side, and Fig. 5(b) and (c) are schematic cross-sectional views taken along line AA in Fig. 5(a), which explain the joining of the terminals.

[0041] As shown in Fig. 5(a), a slit portion S is formed in the first resin sheet 11A. As a result, as shown in Fig. 5(b), the first resin sheet 11A has a folding portion F that can be folded in the thickness direction DT. As shown in Fig. 5(c), in the terminal joining process, the folding portion F is folded in the thickness direction DT to expose the current collector 1, and the exposed current collector 1 and terminal 13 are joined. As shown in Fig. 5(c), the terminal 13 is arranged and joined such that one end is located inside (on the composite layer side) of the outer edge O of the current collector, and the other end is located outside the outer edge O and outside the end of the second resin sheet 11B.

[0042] The method for joining the terminals is not limited, and may be any conventionally known method. The terminals may be made of any conventionally known member used as a voltage detection terminal.

[0043] (5) Secondary sealing treatment The second sealing process will be described with reference to Fig. 6. Fig. 6(a) is a schematic cross-sectional view of an electrode obtained by the second sealing process, and Fig. 6(b) is a schematic perspective view of a terminal portion of the electrode. Fig. 6(c) is a schematic plan view illustrating the shape of the heat-sealed portion (second heat-sealed portion) in the second sealing process.

[0044] 6(a) and (b), the second sealing process is a process for filling the slit portion S by thermally welding the folded portion F to obtain the electrode 20. The slit portion can be regarded as a gap formed in the first resin sheet. Therefore, filling the slit portion can be regarded as melting the resin constituting the first resin sheet by heating and filling the slit portion (gap).

[0045] As shown in FIG. 6(b), it is preferable that the second thermally welded portion H2 in the second sealing process does not overlap with the portion of the terminal 13 that is located outside the outer edge O of the current collector 1.

[0046] The size and planar shape of the second heat-sealed portion are not particularly limited as long as it includes at least a slit portion. The planar shape of the second heat-sealed portion may be, for example, a shape as shown in Fig. 6(c) to (e). The second heat-sealed portion may include the first heat-sealed portion.

[0047] In the second sealing process, it is preferable to perform thermal welding using an impulse machine, in which the heating temperature is, for example, 170° C. or more and 250° C. or less, the cooling temperature is, for example, 40° C. or more and 80° C. or less, and the pressure is, for example, 1000 kN or more and 2500 kN or less.

[0048] (6) Electrode The electrode prepared in the electrode preparation step may be a negative electrode having a current collector, a negative electrode active material layer, and a separator in this order, or a positive electrode having a current collector, a positive electrode active material layer, and a separator in this order. The electrode may also be a bipolar electrode having a negative electrode active material layer, a current collector, and a positive electrode active material layer in this order. In a bipolar electrode, a separator is disposed on the negative electrode active material layer or the positive electrode active material layer.

[0049] 2.Lamination process The lamination step is a step of obtaining an electrode laminate using the electrodes. As shown in Fig. 7(b), the electrode laminate 100 is a laminate in which a plurality of electrodes 20 are laminated in the thickness direction DT.

[0050] FIG. 7(a) is an exploded view illustrating the lamination step, and FIG. 7(b) is a schematic cross-sectional view illustrating an electrode laminate obtained in the lamination step. In the lamination step, as shown in FIG. 7(a), a plurality of electrodes (20A-20C) produced in the electrode production step described above and one electrode member 10 whose outer edge is covered with a resin sheet are laminated via a spacer 40 and a nest 50. The material of the spacer can be the same as the material of the resin sheet. In FIG. 7, the thermally welded first and second resin sheets are illustrated as a resin member 21.

[0051] 7(a) and (b), the electrode 20A has a current collector 1, a composite layer 2A (positive electrode active material layer), and a separator 12 in this order in the thickness direction DT, and functions as a positive electrode terminal electrode (CA) in the electrode laminate. Also, the electrodes 20B and 20C each have a composite layer 2B (negative electrode active material layer), the current collector 1, a composite layer 2A (positive electrode active material layer), and a separator 12 in this order in the thickness direction DT, and functions as a bipolar electrode (BP). Also, the electrode member 10 has a current collector 1 and a composite layer 2B (negative electrode active material layer) in the thickness direction DT, and functions as a negative electrode terminal electrode (NA).

[0052] After stacking, the insert 40 is pulled out to form a liquid injection port (not shown), and the electrolyte 50 is injected through the liquid injection port. The liquid injection port is then sealed to obtain an electrode stack 100 filled with the electrolyte 50 as shown in FIG. 7(b). Examples of the electrolyte include conventionally known electrolytes that can be used in lithium ion batteries. The electrode stack is then housed in an exterior body to obtain a battery. Examples of the exterior body include a laminate exterior body.

[0053] 3.Battery The battery in the present disclosure is typically a lithium ion battery. The battery in the present disclosure is typically a liquid battery (nonaqueous battery) that uses an electrolytic solution as an electrolyte. Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline automobiles, and diesel automobiles. In particular, the battery is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery may also be used as a power source for moving objects other than vehicles (for example, railways, ships, and aircraft), and may also be used as a power source for electrical products such as information processing devices.

[0054] The present disclosure is not limited to the above-described embodiment. The above-described embodiment is merely an example, and any configuration that is substantially the same as the technical idea described in the claims of the present disclosure and that exhibits similar effects is included in the technical scope of the present disclosure. [Explanation of symbols]

[0055] 1...Current collector 2…Mixture layer 10...Electrode member 11A…First resin sheet 11B: Second resin sheet 12…Separator 13...Terminal 20...Electrode 100...electrode laminate S…Slit section F: Bending part

Claims

1. an electrode preparation step of preparing an electrode; A lamination step of obtaining an electrode laminate using the electrode, The electrode preparation step includes: a preparation process for preparing an electrode member including a current collector and a composite layer formed on a first surface of the current collector in a thickness direction; a first sealing process for covering an outer edge portion of the current collector by thermally welding a first resin sheet, which is disposed on the first surface and has two slit portions formed therein, and a second resin sheet, which is disposed on a second surface of the current collector opposite to the first surface, to each other; a separator lamination process for laminating a separator on the electrode member by thermally welding the separator to the first resin sheet; a terminal joining process in which the first resin sheet is folded at a folding portion, which has been made bendable in the thickness direction by the slit portion, to expose the current collector, and the exposed current collector is joined to a terminal; and a second sealing process of heat-sealing the folded portion to fill the slit portion and obtain the electrode.

2. The method for manufacturing a battery according to claim 1 , wherein the thermal welding is performed using an impulse machine in the second sealing process.

3. In the preparation process, a plurality of the electrode members are prepared; the plurality of electrode members after the first sealing process are cross-linked by the first resin sheet and the second resin sheet, 2. The method for manufacturing a battery according to claim 1, further comprising a sheet-by-sheet process, after the separator lamination process and before the terminal joining process, cutting the first resin sheet and the second resin sheet at bridged portions to separate the plurality of electrode members into sheets.

4. The method for producing a battery according to claim 1 , wherein the electrode is a bipolar electrode having a positive electrode active material layer, the current collector, and a negative electrode active material layer in this order in the thickness direction.

5. 2. The battery manufacturing method according to claim 1, wherein in the separator lamination process, the first resin sheet and the separator are thermally welded together at an edge of the first resin sheet extending in a direction perpendicular to an extension direction of the edge of the first resin sheet in which the slit portion is formed.

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