Method for manufacturing battery

Abstract

To provide a manufacturing method of a battery capable of suppressing intrusion of foil sagging and burrs between layers of an electrode laminate in a cutting process of the electrode laminate.SOLUTION: A method for producing a battery including a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order, the method including a step of preparing an electrode laminate in which the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector are laminated, and a step of cutting the electrode laminate in a state where the electrode laminate is fixed by a jig in a lamination direction of the electrode laminate, the jig has an elastic body in a region facing at least a part of the thin layer region.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Various technologies have been proposed for batteries such as those disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-137711 Summary of the Invention [Problem to be solved by the invention]

[0004] In the process of cutting an electrode laminate, which is a laminate of multiple electrode layers and current collectors, foil sagging of the current collectors and burrs in the electrode layers may occur during battery manufacturing. These foil sagging and burrs in the electrode laminate may cause a short circuit in the battery. Patent Document 1 discloses a battery in which the end of the current collector (negative electrode current collector layer or positive electrode current collector layer) is positioned more inward than the end of the electrode layer (negative electrode layer or positive electrode layer). However, a stacking phase difference occurs at the end where the current collector is not positioned, and there is a risk that foil sagging or burrs may enter the gap.

[0005] The present disclosure has been made in consideration of the above-described circumstances, and has as its main object to provide a battery manufacturing method that can suppress the intrusion of foil sagging and burrs between layers of an electrode laminate during the cutting process of the electrode laminate. [Means for solving the problem]

[0006] That is, the present disclosure includes the following aspects. <1> A method for manufacturing a battery including a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order, comprising: preparing an electrode stack in which the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector are stacked; and cutting the electrode stack while the electrode stack is fixed in a stacking direction of the electrode stack by a jig, the electrode stack has a thin layer region whose thickness in the stacking direction is relatively thinner than other regions, The method for manufacturing a battery, wherein the jig has an elastic body in an area facing at least a part of the thin layer area.

[0007] <2> The thin layer region is located at least in a part of the peripheral edge portion in the planar direction of the electrode stack. <1> A method for manufacturing the battery described in claim 1.

[0008] <3> the elastic body has a shape in which the thickness in the stacking direction becomes thinner toward the center in the planar direction of the electrode stack; <1> or <2> A method for manufacturing the battery described in claim 1.

[0009] <4> The elastic body is silicone rubber. <1> ~ <3> 10. A method for manufacturing a battery according to any one of the preceding claims.

[0010] <5> The elastic body is disposed in an area facing the entire thin layer area. <1> ~ <4> 10. A method for manufacturing a battery according to any one of the preceding claims. [Effects of the Invention]

[0011] The battery manufacturing method of the present disclosure can suppress the intrusion of foil sagging and burrs between layers of the electrode laminate during the cutting step of the electrode laminate. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of an electrode laminate according to the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing an example of the cutting step of the present disclosure. [Figure 3] FIG. 3 is a schematic plan view showing the jig and electrode stack of Example 1. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described. It should be noted that matters other than those specifically mentioned in this specification that are necessary for implementing the present disclosure (for example, the general configuration and manufacturing process of a battery that do not characterize the present disclosure) can be understood as design matters for those skilled in the art based on prior art in the relevant field. The present disclosure can be implemented based on the contents disclosed in this specification and common general technical knowledge in the relevant field.

[0014] The present disclosure provides a method for manufacturing a battery including a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order, the method comprising: a step of preparing an electrode laminate in which the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector are stacked (hereinafter, this step may be referred to as an electrode laminate preparation step); and cutting the electrode stack while the electrode stack is fixed in a stacking direction of the electrode stack by a jig (hereinafter, sometimes referred to as a cutting step), the electrode stack has a thin layer region whose thickness in the stacking direction (hereinafter sometimes referred to as the stacking direction thickness) is relatively thinner than other regions, The jig has an elastic body in an area facing at least a part of the thin layer area.

[0015] In the present disclosure, the electrode laminate has a thin layer region in which the total thickness in the stacking direction of the layers constituting the electrode laminate (hereinafter sometimes referred to as "constituent layers") is relatively thinner than other regions. Specifically, the thin layer region of the electrode laminate has a thickness in the stacking direction that is relatively thinner than other regions because at least one of the constituent layers is absent, the thickness in the stacking direction of at least one constituent layer is thinner than other regions, or both. In other words, the thin layer region has a structure in which there is a gap between adjacent constituent layers. Typically, the thin layer region has a relatively thinner thickness in the stacking direction than other regions due to the absence of at least one of the constituent layers. For example, at least one of the positive electrode current collector, positive electrode layer, solid electrolyte layer, negative electrode layer, and negative electrode current collector constituting the electrode stack has a different shape or size in the planar direction from the other layers, resulting in a region in the peripheral portion of the electrode stack where that layer is absent or where only that layer is present, resulting in a stacking phase difference. Here, the planar direction of the electrode laminate means the direction in which a plane perpendicular to the lamination direction extends.

[0016] In the present disclosure, in the cutting process of an electrode laminate having such a thin layer region, the electrode laminate is fixed in its stacking direction by a jig having an elastic body provided in a region facing at least a part of the thin layer region. Here, the region of the jig facing the thin layer region of the electrode laminate is a surface that faces the electrode laminate in the stacking direction and comes into contact with the thin layer region of the electrode laminate when the electrode laminate is fixed in its stacking direction by the jig. By fixing the electrode stack with the jig described above, the elastic body applies surface pressure in the stacking direction to the thin layer region of the electrode stack. As a result, the gaps between the constituent layers of the thin layer region are reduced, preventing foil sagging and burrs from entering these gaps. Furthermore, chips generated during cutting can also be prevented from entering the gaps between the constituent layers. In other words, according to the present disclosure, it is possible to prevent the occurrence of short circuits in the battery.

[0017] Each step in the manufacturing method of the present disclosure will be described below. [Electrode stack preparation process] The electrode stack preparation step is a step of preparing an electrode stack in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are stacked in this order, and which has a thin layer region whose thickness in the stacking direction is relatively thinner than other regions. 1 is a cross-sectional schematic view showing an example of an electrode laminate according to the present disclosure, specifically a partially enlarged view showing an example of a cross section of an electrode laminate according to the present disclosure. As shown in FIG. 1, the electrode stack 100 has a structure 160 (hereinafter sometimes referred to as a unit structure) in which a positive electrode current collector 110, a positive electrode layer 120, a solid electrolyte layer 130, a negative electrode layer 140, and a negative electrode current collector 150 are stacked in this order.

[0018] The electrode stack 100 also has a thin region T whose thickness in the stacking direction is relatively thinner than other regions. The electrode stack 100 has uneven edges in its planar peripheral portion, and includes a mixture of layers that protrude further than the other layers and layers whose edges are located further inward than the peripheral portion. Specifically, the negative electrode current collector 150 has an exposed portion at its peripheral portion where the negative electrode layer 140 is not laminated, and protrudes compared to the negative electrode layer 140, solid electrolyte layer 130, positive electrode layer 120, and positive electrode current collector 110. Furthermore, the peripheral portion of the negative electrode layer 140 adjacent to the negative electrode current collector 150 protrudes further than the solid electrolyte layer 130. Similarly, the peripheral portion of the solid electrolyte layer 130 protrudes further than the adjacent positive electrode layer 120 and positive electrode current collector 110. In this way, a thin layer region T exists at the peripheral edge of the electrode stack 100 in the planar direction, and the thin layer region T has a thickness gradient in which the thickness in the stacking direction increases toward the center of the electrode stack 100 in the planar direction.

[0019] The constituent layer that makes the thin layer region a thin layer is not particularly limited, and may be any one layer of a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector, or may be two or more layers. For example, from the viewpoint of current collection efficiency on the negative electrode side, the negative electrode current collector may be made to protrude from one end in the planar direction of the electrode laminate, and from the same viewpoint, the positive electrode current collector may be made to protrude from one end in the planar direction of the electrode laminate. Furthermore, the effects of the present disclosure can be obtained whether the thickness of the thin layer region in the stacking direction has a gradient as shown in FIG. 1 or a uniform thickness different from that shown in FIG.

[0020] Although the electrode stack 100 has a thin layer region T on its peripheral edge in the planar direction, the position of the thin layer region is not limited in the present disclosure. In addition, in the case of an electrode stack having a thin layer region on its peripheral edge in the planar direction, the electrode stack may have a thin layer region over the entire peripheral edge, or may have a thin layer region on at least a portion of the peripheral edge.

[0021] Furthermore, although the electrode stack 100 has a structure in which a plurality of unit structures 160 are stacked, the electrode stack in the present disclosure may also include a single unit structure. When multiple unit structures are included, the stacking format of the unit structures is not particularly limited and may be in series or in parallel. Adjacent unit structures may share a current collector as in the electrode stack 100 of FIG. 1, or may have their current collectors stacked together. Each layer of the electrode stack will be described below.

[0022] <Positive electrode current collector> Examples of materials for the positive electrode current collector include metals such as Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, and SUS. Examples of the shape of the positive electrode current collector include a foil shape, a plate shape, etc. The shape of the positive electrode current collector in a plan view is not particularly limited, but examples thereof include a circle, an ellipse, a rectangle, and any polygonal shape. The thickness of the positive electrode current collector is, for example, 0.1 μm or more and 1 mm or less. The positive electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface thereof. <Positive electrode layer> The positive electrode layer contains a positive electrode active material, and may optionally contain a solid electrolyte, a conductive material, a binder, a thickener, etc. The thickness of the positive electrode layer is not particularly limited and is usually 0.1 μm or more and 1 mm or less.

[0023] The positive electrode active material may be, for example, an oxide active material. 0.8Co 0.15 Al 0.05 O2, LiCoO2, LiMnO2, LiNiO2, LiVO2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiMn2O4, Li(Ni 0.5 Mn 1.5 )O4, LiFePO4, LiMnPO4, LiNiPO4, LiCuPO4, etc. The positive electrode active material may be positive electrode active material particles. The average particle size of the positive electrode active material particles is not particularly limited, and may be 1 nm to 100 μm. The content of the positive electrode active material in the positive electrode layer is not particularly limited, and may be 50.00 to 99.00 mass %.

[0024] At least a portion of the surface of the positive electrode active material may be coated with a lithium ion conductive compound. The lithium ion conductive compound may cover at least a part of the surface of the positive electrode active material, or may cover the entire surface of the positive electrode active material. Examples of lithium ion conductive compounds include B2O3, Li2B4O7, LiBPO4, Li3PO4, LiPO3, and LiNbO3. The thickness of the lithium ion conductive compound coating is, for example, 0.1 nm or more, and may be 1 nm or more. On the other hand, the thickness of the lithium ion conductive compound is, for example, 100 nm or less, and may be 20 nm or less. The coverage of the lithium ion conductive compound coating the positive electrode active material is, for example, 70% or more, and may be 90% or more, or even 100%. The method for coating the lithium ion conductive compound is not particularly limited, and any conventionally known method may be used as appropriate.

[0025] The solid electrolyte may be a solid electrolyte contained in a solid electrolyte layer, which will be described later. The content of the solid electrolyte in the positive electrode layer is not particularly limited.

[0026] Examples of conductive materials include carbon materials, metal particles, conductive polymers, etc. Examples of carbon materials include particulate carbon materials such as acetylene black (AB) and ketjen black (KB), and fibrous carbon materials such as carbon fibers, carbon nanotubes (CNT), and carbon nanofibers (CNF). The content of the conductive material in the positive electrode layer is not particularly limited.

[0027] Examples of binders include acrylonitrile butadiene rubber (NBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and styrene-butadiene rubber (SBR). The content of the binder in the positive electrode layer is not particularly limited.

[0028] Examples of thickeners include polysaccharides such as carboxymethyl cellulose (CMC) and methyl cellulose.

[0029] The positive electrode layer may be formed by mixing and pressing materials constituting the positive electrode layer, or by applying a positive electrode slurry to at least one surface of a support such as a positive electrode current collector and drying the mixture. The positive electrode slurry contains a positive electrode active material and a solvent, and may also contain a solid electrolyte, a conductive material, a binder, a thickener, a solvent, and the like, as necessary. The method for applying the positive electrode slurry is not particularly limited, and examples thereof include a doctor blade method, a metal mask printing method, an electrostatic coating method, a dip coating method, a spray coating method, a roll coating method, a gravure coating method, and a screen printing method. The support can be appropriately selected from those having self-supporting properties and is not particularly limited, and examples thereof include metal foils such as Cu and Al foils.

[0030] Examples of the solvent include an aqueous solvent and an organic solvent. The aqueous solvent refers to water or a mixed solvent containing water and a polar organic solvent. For example, an appropriate solvent can be selected depending on the types of the positive electrode active material, binder, etc. As the aqueous solvent, water is preferably used because of its ease of handling. Examples of polar organic solvents that can be used in the mixed solvent include alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone, and ethers such as tetrahydrofuran. Examples of the organic solvent include 1,2,3,4-tetrahydronaphthalene, n-heptane, butyl butyrate, diisobutyl ketone, and N-methyl-2-pyrrolidone (NMP).

[0031] <Solid electrolyte layer> The solid electrolyte layer includes at least a solid electrolyte. The thickness of the solid electrolyte layer is not particularly limited, but is usually 0.1 μm or more and 1 mm or less. As the solid electrolyte contained in the solid electrolyte layer, any known solid electrolyte that can be used in solid-state batteries can be appropriately used, and examples thereof include sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, etc. In order to prevent the positive electrode layer and the negative electrode layer from peeling off from the solid electrolyte layer, a relatively soft sulfide solid electrolyte may be used as the solid electrolyte.

[0032] Examples of sulfide solid electrolytes include solid electrolytes containing Li, M (where M is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In), and S. The sulfide solid electrolyte may further contain at least one of O and a halogen element. Examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-SiS2, LiX-Li2S-SiS2, LiX-Li2S-P2S5, LiX-Li2O-Li2S-P2S5, LiX-Li2S-P2O5, LiX-Li3PO4-P2S5, and Li3PS4. The term "Li2S-P2S5" above refers to a material obtained using a raw material composition containing Li2S and P2S5, and the same applies to other terms. Furthermore, the "X" in the LiX represents a halogen element. Examples of halogen elements include F, Cl, Br, and I. The raw material composition containing LiX may contain one or more types of LiX. When two or more types of LiX are contained, the mixing ratio of the two or more types is not particularly limited. The molar ratio of each element in the sulfide solid electrolyte can be controlled by adjusting the content of each element in the raw materials. The molar ratio and composition of each element in the sulfide solid electrolyte can be measured, for example, by ICP atomic emission spectrometry.

[0033] The sulfide solid electrolyte may be a sulfide glass, a crystallized sulfide glass (glass ceramics), or a crystalline material obtained by a solid-phase reaction treatment of a raw material composition. The crystalline state of the sulfide solid electrolyte can be confirmed, for example, by subjecting the sulfide solid electrolyte to powder X-ray diffraction measurement using CuKα radiation.

[0034] Examples of oxide solid electrolytes include substances having a garnet-type crystal structure containing Li, La, A (A is at least one of Zr, Nb, Ta, and Al), and O. Examples of oxide solid electrolytes include Li2O-B2O3-P2O5, Li2O-SiO2, Li2O-B2O3, Li 1.3 Al 0.3 Ti 0.7 (PO4)3, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O 12 , Li 3.6 Si 0.6 P 0.4 O4, Li4SiO4, Li3PO4, and Li 3+x PO 4-x N x (1≦x≦3) etc. may also be used.

[0035] The halide solid electrolyte may be, for example, a solid electrolyte containing Li, M, and X (M represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br).

[0036] The solid electrolyte may be in the form of particles from the viewpoint of ease of handling. The average particle size (D50) of the solid electrolyte particles is not particularly limited and may be from 1 nm to 100 μm.

[0037] The solid electrolyte may be used alone or in combination of two or more. When two or more solid electrolytes are used, the two or more solid electrolytes may be mixed, or two or more solid electrolyte layers may be formed to form a multilayer structure. The proportion of the solid electrolyte in the solid electrolyte layer is not particularly limited, but is, for example, 50% by mass or more, and may be in the range of 60% by mass to 100% by mass, 70% by mass to 100% by mass, or even 100% by mass. The solid electrolyte may contain less than 10% by mass of electrolytic solution relative to the total amount of electrolyte. The solid electrolyte may also be a composite solid electrolyte containing an inorganic solid electrolyte and a polymer electrolyte.

[0038] The solid electrolyte layer may contain a binder from the viewpoint of exhibiting plasticity, etc. Examples of such binders include the materials exemplified as the binders used in the positive electrode layer described above. However, in order to facilitate achieving high output, the binder content in the solid electrolyte layer may be 5 mass % or less from the viewpoint of preventing excessive aggregation of the solid electrolyte and enabling the formation of a solid electrolyte layer having a uniformly dispersed solid electrolyte.

[0039] <Negative electrode layer> The negative electrode layer contains a negative electrode active material, and may optionally contain a solid electrolyte, a conductive material, a binder, a thickener, etc. The thickness of the negative electrode layer is not particularly limited and is usually 0.1 μm or more and 1 mm or less. Examples of negative electrode active materials include silicon-based active materials such as Si and Si alloys, silicon oxide, and the like, carbon-based active materials such as graphite and hard carbon, various oxide-based active materials such as lithium titanate, tin and tin alloys, metallic lithium, and lithium alloys. The content of the negative electrode active material in the negative electrode layer is not particularly limited, and may be 50.00 to 100% by mass. The solid electrolyte, conductive material, binder, and thickener can be appropriately selected from the solid electrolytes, conductive materials, binders, and thickeners that can be used in the positive electrode layer, respectively. The contents of the solid electrolyte, conductive material, binder, and thickener in the negative electrode layer are not particularly limited.

[0040] The negative electrode layer may be formed by mixing and pressing materials constituting the negative electrode layer, or by applying a negative electrode slurry to at least one surface of a support such as a negative electrode current collector described below and drying the mixture.

[0041] <Negative electrode current collector> The material of the negative electrode current collector may be a material that does not alloy with Li, and examples thereof include SUS, Al, Cu, Ni, Fe, Ti, and carbon. Examples of the shape of the negative electrode current collector include a foil shape, a plate shape, etc. The shape of the negative electrode current collector in a plan view is not particularly limited, but examples thereof include a circle, an ellipse, a rectangle, and any polygonal shape. The thickness of the negative electrode current collector varies depending on the shape, but may be, for example, in the range of 1 μm to 50 μm, or in the range of 5 μm to 20 μm. The negative electrode current collector may have a buffer layer, an elastic layer, or a PTC thermistor layer disposed on its surface.

[0042] The method for producing the electrode laminate is not particularly limited, and known methods can be appropriately adopted. For example, the electrode laminate may be produced by separately preparing a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector, and then laminating these. Typically, the electrode laminate has thin layer regions due to differences in the planar shapes and planar sizes of these constituent layers. The electrode laminate may be appropriately pressed to make it dense.

[0043] [Cutting process] The cutting step is a step of cutting the electrode stack while the electrode stack is fixed in the stacking direction by a jig, and the jig has an elastic body in an area facing at least a part of the thin layer area of ​​the electrode stack. FIG. 2 is a schematic diagram showing an example of the cutting step of the present disclosure. The jig 200 shown in FIG. 2 can fix the electrode stack 100 in the stacking direction by sandwiching the electrode stack 100 between a solid jig bottom plate 210 and a fixed jig plate 220 and tightening the fastening bolts 230.

[0044] The fixing jig plate 220 is provided with an elastic body 240A in at least a part of a region facing the thin layer region T of the electrode stack 100. Similarly, the fixing jig bottom plate 210 is provided with an elastic body 240B in a region facing at least a part of the thin layer region T of the electrode stack 100. The thin layer region T has a thickness gradient in which the thickness in the stacking direction increases toward the center in the planar direction of the electrode stack 100. Corresponding to this thickness in the stacking direction, the elastic bodies 240A, 240B have a shape in which the thickness in the stacking direction decreases toward the center in the planar direction of the electrode stack 100. When the fastening bolt 230 is tightened, a compressive force is applied to the electrode stack 100 in the stacking direction, and this compressive force is also applied to the elastic bodies 240A and 240B, resulting in the interlayer gaps in the thin layer region T of the electrode stack 100 being crushed.

[0045] With the compressive force applied to the thin layer region T by the elastic body 240 in this manner, the electrode laminate 100 is cut by the cutting blade 300. The cutting blade 300 has a circular saw blade 310 that rotates (in the rotation direction R) around a rotation axis 320. Although not shown, the fixing jig plate 220 has an insertion opening into which the circular saw blade 310 can be inserted. The electrode laminate 100 can be cut by moving it relative to the rotating circular saw blade 310 (in the direction of arrow F in FIG. 2).

[0046] The elastic body has a function of applying a load to the thin layer region to reduce the interlayer gap in the thin layer region when the electrode stack is fixed, and is compressible in the stacking direction of the electrode stack when the electrode stack is fixed, and deforms along the thickness of the electrode stack in the stacking direction, thereby preventing the application of an excessive load to the thin layer region. The elastic body may be any material that can be compressed in whole or in part by the force that fixes the electrode stack in the stacking direction, thereby reducing its thickness in the stacking direction. Materials that can be used include, for example, silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, nitrile rubber, and styrene butadiene rubber.

[0047] The elastic body is disposed in at least a portion of the region of the jig that faces the thin layer region of the electrode laminate. The elastic body may be disposed in at least a portion of the region that faces the thin layer region, but in order to more effectively suppress the occurrence of foil sagging and burrs, the elastic body may be disposed in a region that faces more thin layer regions, or in a region that faces the entire thin layer region. An example of disposing the elastic body in a portion of the region that faces the thin layer region is a region where foil sagging and burrs are likely to occur, such as a thin layer region that is adjacent to the cut surface.

[0048] The shape of the elastic body is not particularly limited, and may be, for example, a plate-like shape, or a shape whose thickness varies along the thickness of the thin layer region in the stacking direction. By using an elastic body having a thickness corresponding to the thickness of the thin layer region in the stacking direction, the surface pressure applied to the thin layer region is more easily uniformed, and the gaps between the constituent layers of the thin layer region can be effectively reduced. An example of a shape with varying thickness is a shape in which the thickness in the stacking direction becomes thinner toward the center in the planar direction of the electrode laminate, as shown in Figure 2. When there is a thin layer region in the peripheral portion of the electrode laminate where the thickness in the stacking direction becomes thicker toward the center in the planar direction of the electrode laminate, it is possible to effectively apply surface pressure to the thin layer region.

[0049] The method for cutting the electrode laminate is not particularly limited, and any known cutting blade capable of cutting the electrode laminate may be used, including, for example, a circular blade such as a circular saw blade, a slitter blade, or a gang blade, and a flat blade such as a cutter blade, a push cutter blade, a razor blade, or a rotary cutter.

[0050] The type of battery is not particularly limited, and examples thereof include lithium ion batteries. The battery may be a primary battery or a secondary battery. The battery may be a solid battery in which the electrolyte layer contains a solid electrolyte. The solid battery may be a semi-solid battery or an all-solid battery. In the present disclosure, a semi-solid battery is a battery in which the electrolyte layer contains an inorganic solid electrolyte and a liquid component (e.g., an ionic liquid). In the present disclosure, an all-solid battery is a battery in which the electrolyte layer contains only an inorganic solid electrolyte as the electrolyte. The shape of the battery is not particularly limited, and may be, for example, a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, or a laminate type. 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-powered vehicles, and diesel-powered vehicles. In particular, the battery may be 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 mobile objects other than vehicles (for example, trains, ships, and aircraft), and as a power source for electrical appliances such as information processing devices. [Example]

[0051] Example 1 [Electrode laminate preparation process] An electrode laminate was prepared in which a plurality of unit structures each having a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector laminated in this order were laminated.

[0052] Fig. 3 is a schematic plan view showing the jig and electrode stack of Example 1. Specifically, Fig. 3 is a schematic plan view of the jig 400 to which the electrode stack 100A is fixed, as viewed from the fixing jig plate 420 side. The electrode laminate 100A has a thin layer region T1 where the end of the negative electrode current collector protrudes beyond the other layers at its peripheral edge in the planar direction and only the negative electrode current collector is laminated, a thin layer region T2 where the negative electrode current collector, a negative electrode layer, a solid electrolyte layer, and a positive electrode layer are laminated, a thin layer region T4 where the positive electrode current collector, a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated, and a thin layer region T3 where the end of the positive electrode current collector protrudes beyond the other layers at its peripheral edge in the planar direction and only the positive electrode current collector is laminated. The remaining regions are regions where the positive electrode current collector, positive electrode layer, solid electrolyte layer, negative electrode layer, and negative electrode current collector are all laminated and where the thickness in the stacking direction is greatest (hereinafter, sometimes referred to as the thickest region).

[0053] [Cutting process] First, the electrode stack 100A was fixed using a jig 400 shown in FIG. In FIG. 3, fixture plate 420 is divided into two pieces (420A, 420B), and the gap between these fixture plates (420A, 420B) forms cut line 420C where the cutting blade enters, allowing electrode stack 100A to be cut. On the fixing jig plate 420B, 1.5 mm thick silicone rubbers 440A and 440C were placed in a portion of the area facing the thin layer regions T1 and T3 of the electrode stack 100A, and 0.5 mm thick silicone rubbers 440B and 440D were placed in a portion of the area facing the thin layer regions T2 and T4. Although not shown, silicone rubbers 440A, 440B, 440C, and 440D were also placed on the fixing jig bottom plate 410 in parts of the areas facing the thin layer areas T1, T2, T3, and T4 of the electrode stack 100A.

[0054] With electrode stack 100A sandwiched between fixture bottom plate 410 and fixture plates 420A and 420B so that each silicone rubber and each thin layer region faced each other, fastening bolts 430 were tightened to fix electrode stack 100A. Next, the electrode stack 100A was cut along the cut line 420C with a circular saw blade (not shown).

[0055] [evaluation] In the cutting step, the surface pressure applied to the electrode stack 100A in the stacking direction was measured. In Example 1, it was confirmed that the thin layer regions T1, T2, T3, and T4 of the electrode laminate 100A were subjected to the same surface pressure as the thickest region. In other words, by disposing the elastic bodies 440A, 440B, 440C, and 440D, the elastic bodies in each thin layer region were crushed to conform to the electrode laminate 100A, and the gaps created by the layer phase difference of the electrode laminate 100A were crushed and reduced. This prevented the current collector from sagging and the electrode layer from burring into the gaps. It also prevented the intrusion of chips.

[0056] (Comparative Example 1) [Evaluation] was performed in the same manner as in Example 1, except that in the [Cutting Process], none of the silicone rubbers 440A, 440B, 440C, and 440D was placed on either the fixing jig bottom plate 410 or the fixing jig plate 420. Although pressure was applied to the thickest region, no pressure was applied to the thin regions T1, T2, T3, and T4, and it was confirmed that the gaps between the constituent layers of the thin regions were maintained. In particular, almost no pressure was applied to the thin regions T1 and T3, where only the current collector was laminated. [Explanation of symbols]

[0057] 100, 100A electrode stack 110 Positive electrode current collector 120 Positive electrode layer 130 Solid electrolyte layer 140 negative electrode layer 150 Negative electrode current collector 160 Unit Structure T, T1, T2, T3, T4 thin layer area 200 Jig 210 Fixed jig bottom plate 220 Fixture plate 230 Fastening bolt 240 (240A, 240B) Elastic body 300 cutting blade 310 Circular saw blade 320 Rotational Axis F Supply direction R Rotation direction 400 Jig 410 Fixed jig bottom plate 420, 420A, 420B Fixture Plate 420C Cut Line 430 Fastening bolt 440 (440A, 440B, 440C, 440D) Elastic body

Claims

1. A method for manufacturing a battery including a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order, comprising: preparing an electrode stack in which the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector are stacked; and cutting the electrode stack while the electrode stack is fixed in a stacking direction of the electrode stack by a jig, the electrode stack has a thin layer region whose thickness in the stacking direction is relatively thinner than other regions, The method for manufacturing a battery, wherein the jig has an elastic body in an area facing at least a part of the thin layer area.

2. The method for manufacturing a battery according to claim 1 , wherein the thin layer region is located at least in a part of a peripheral edge portion in a planar direction of the electrode laminate.

3. The method for manufacturing a battery according to claim 1 , wherein the elastic body has a shape in which the thickness in the stacking direction decreases toward the center in the planar direction of the electrode stack.

4. The method for manufacturing a battery according to claim 1 , wherein the elastic body is silicone rubber.

5. The method for manufacturing a battery according to claim 1 , wherein the elastic body is disposed in an area facing the entire thin layer area.

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