Battery manufacturing method

Abstract

The present disclosure provides a method for manufacturing a battery that can suppress cracking of a heat-treated electrode active material layer. [Solution] A method for manufacturing a battery disclosed herein includes conveying a laminate having a base material layer and an electrode active material layer, the laminate having been heated to a temperature of 120°C or higher, by a roller such that the conveying direction of the laminate is changed by 45° or more along a direction-changing roller. In the method disclosed herein, the temperature difference between the laminate and the direction-changing roller after heating is 80°C or less.

Description

[Technical Field]

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

[0002] As disclosed in Patent Documents 1 to 5, techniques have been developed for drying electrode active material layers that constitute electrode laminates for batteries. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2017-183214 [Patent Document 2] Patent Publication No. 2016-103402 [Patent Document 3] Patent Publication No. 2008-147114 [Patent Document 4] Patent Publication No. 2014-032767 [Patent Document 5] Patent Publication No. 2017-191678 Summary of the Invention [Problem to be solved by the invention]

[0004] In manufacturing a battery, it is desirable to prevent cracks in the electrode active material layer that has been heat-treated for drying or the like.

[0005] An object of the present disclosure is to provide a method for manufacturing a battery that can suppress cracking of a heat-treated electrode active material layer. [Means for solving the problem]

[0006] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> conveying the laminate, which has been heated to a temperature of 120°C or higher and includes a base material layer and an electrode active material layer, by a roller such that the conveying direction of the laminate is changed by 45° or more along a direction-changing roller; and the direction-changing roller has a temperature adjusting function, and the temperature difference between the laminate and the direction-changing roller after heating is 80°C or less; How batteries are manufactured. <Aspect 2> 2. The method of claim 1, wherein the temperature difference is 50° C. or less. <Aspect 3> Further comprising drying the electrode active material layer before the roller conveyance; and In the drying step, the laminate is heated to a temperature of 120°C or higher. 3. The method according to embodiment 1 or 2. <Aspect 4> 4. The method of claim 3, wherein the drying step involves laser heating the laminate. <Aspect 5> Aspect 5. The method of any one of aspects 1 to 4, further comprising adjusting the temperature of the laminate by at least one temperature adjustment mechanism after the roller conveyance. [Effects of the Invention]

[0007] According to the disclosed method for manufacturing a battery, cracking of the heat-treated electrode active material layer can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the disclosed method for manufacturing a battery. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of the disclosed method for manufacturing a battery. [Figure 3] FIG. 3 is a schematic diagram illustrating an example of the disclosed method for manufacturing a battery. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure.

[0010] <Battery manufacturing method> The disclosed method for manufacturing a battery includes conveying a laminate having a base material layer and an electrode active material layer, the laminate having been heated to a temperature of 120°C or higher, by a roller such that the conveying direction of the laminate is changed by 45° or more along a direction-changing roller. In the disclosed method, the direction-changing roller has a temperature adjusting function, and the temperature difference between the laminate and the direction-changing roller after heating is 80°C or less.

[0011] The present inventors have considered that one of the reasons why an electrode active material layer heated to a predetermined temperature of 120°C or higher is prone to cracking is that the moisture content in the electrode active material layer is reduced, thereby reducing the flexibility of the electrode active material layer.

[0012] The present inventors have discovered that, in manufacturing a battery, cracking of the heat-treated electrode active material layer can be suppressed by conveying a laminate having a base layer and an electrode active material layer heated to a temperature of 120°C or higher along a direction-changing roller whose temperature difference from the heated laminate is less than a predetermined value, while changing the conveying direction of the laminate by 45° or more. The reason for this is presumed to be as follows, without intending to be bound by any theory. Specifically, for example, when a laminate at room temperature is changed in direction by 45° or more along a direction-changing roller, it is believed that the electrode active material layer of the laminate is broken down by the multiple electrode active materials bound together by the binder, resulting in cracks in the electrode active material layer. In contrast, it is believed that the flexibility of the binder in the electrode active material layer of a laminate heated to a temperature of 120°C or higher is improved. In this state, by turning the laminate including the electrode active material layer by 45° or more along the direction-changing roller, a moderate stress is applied to the electrode active material layer including the highly flexible binder, which is believed to allow the binder to stretch and spread while still binding the electrode active material together. Furthermore, by using a direction-changing roller whose temperature difference with the heated electrode active material layer is below a predetermined value, it is believed that the binder's high flexibility can be effectively maintained. As a result, it is believed that cracking of the electrode active material layer is suppressed.

[0013] The method of manufacturing an electrode according to the present disclosure will be described below with reference to the drawings, in which the dimensional relationships do not reflect the actual dimensional relationships.

[0014] 1 to 3 are schematic diagrams illustrating an example of how the electrode active material layer is wound from a winding reel 41 onto a winding reel 42 after being heated, conveyed by rollers, and optionally subjected to temperature adjustment.

[0015] <Roller conveying process> 1 , the method of the present disclosure includes conveying the laminate 1, which has been heated to a temperature of 120° C. or higher and includes a base material layer and an electrode active material layer, by changing the conveying direction of the laminate 1 by 45° or more along a direction-changing roller 20. When the angle at which the conveying direction of the laminate is changed is within the above range, cracking of the electrode active material layer can be effectively suppressed.

[0016] The heating temperature may be 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, 190°C or higher, or 200°C or higher, and may be 300°C or lower, 290°C or lower, 280°C or lower, 270°C or lower, 260°C or lower, or 250°C or lower. It is believed that a heating temperature within the above range is likely to result in a decrease in moisture content in the electrode active material layer, a decrease in flexibility due to binder degradation, and the like. Based on this assumption, applying the method of the present disclosure to an electrode active material layer that has undergone heat treatment at a temperature within the above range is particularly effective.

[0017] The angle at which the conveying direction of the laminate is changed may be 60° or more, 70° or more, 80° or more, 85° or more, or 90° or more, and may be 180° or less, 150° or less, 130° or less, 120° or less, 110° or less, 100° or less, 95° or less, or 90° or less.

[0018] In the method of the present disclosure, the direction-changing roller has a temperature adjusting function, and the temperature difference between the laminate and the direction-changing roller after heating is 80°C or less. This configuration allows the heated laminate to be maintained at a predetermined temperature or higher, thereby effectively suppressing cracking of the electrode active material layer. This temperature difference may be 0°C or higher, 5°C or higher, 10°C or higher, 15°C or higher, 20°C or higher, 25°C or higher, or 30°C or higher, or may be 80°C or lower, 70°C or lower, 60°C or lower, 55°C or lower, 50°C or lower, 45°C or lower, 40°C or lower, 35°C or lower, or 30°C or lower.

[0019] The temperature of the direction-changing roller may be lower than the temperature of the laminate. That is, the temperature difference may refer to the temperature of the laminate minus the temperature of the direction-changing roller.

[0020] Furthermore, this temperature difference may particularly refer to the temperature difference between the electrode active material layer in the laminate and the direction-changing roller.

[0021] In the method of the present disclosure, the temperature of the laminate during the change of direction is not particularly limited, but may be 40°C or higher. When this temperature is within the above range, cracking of the electrode active material layer can be effectively suppressed. This temperature may be 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°C or higher, and may be 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, 110°C or lower, or 100°C or lower. This temperature can be appropriately set taking into consideration the softening temperature of the binder, etc. Note that this temperature may particularly refer to the temperature of the electrode active material layer of the laminate.

[0022] The temperature of the stack may be monitored by a thermometer, such as a temperature sensor, which may in particular be a non-contact radiation thermometer.

[0023] In the method of the present disclosure, the temperature of the direction-changing roller may be adjustable in accordance with the temperature of the heated laminate, and the temperature of the direction-changing roller may be controlled in accordance with a signal input from the thermometer, for example.

[0024] The diameter of the direction-changing roller is not particularly limited, and may be 35 mm or more, 40 mm or more, 45 mm or more, 50 mm or more, or 55 mm or more, and may be 300 mm or less, 250 mm or less, 200 mm or less, 150 mm or less, 130 mm or less, 120 mm or less, 110 mm or less, or 100 mm or less. When the diameter of the direction-changing roller is within the above range, cracking of the electrode active material layer can be effectively suppressed.

[0025] The peripheral speed of the direction-changing roller is not particularly limited, and can be set appropriately taking into consideration the viewpoints of suppressing cracking of the electrode active material layer, ease of conveyance, and the like.

[0026] The substrate layer in the method of the present disclosure is not particularly limited, but examples thereof include a current collector and a release sheet. For example, when the substrate layer is a current collector, the laminate subjected to the method of the present disclosure can be used as is for manufacturing a battery. Furthermore, when the substrate layer is a release sheet, the electrode active material layer of the laminate subjected to the method of the present disclosure can be peeled from the substrate layer, which is the release sheet, and transferred to a current collector, which can be used for manufacturing a battery.

[0027] <Drying process> The method of the present disclosure may further include drying the electrode active material layer before conveying with rollers, and in the drying step, the laminate 1 may be heated to a temperature of 120° C. or higher.

[0028] In the drying step, for example, the laminate 1 may be heated by laser or infrared. From the viewpoint of efficiently heating the laminate 1, the laminate 1 may be heated by laser, particularly in the drying step. In addition, air blowing may be used in combination in the drying step. The air blowing may be hot air.

[0029] Drying may be performed by a predetermined heating unit 10. Heating and roller conveyance may be performed continuously or discontinuously. For example, in FIGS. 1 to 3, the laminate is conveyed by rollers even during heating, and thus heating and roller conveyance are performed continuously. In contrast, the laminate does not need to be conveyed by rollers during heating, and thus heating and roller conveyance may be performed discontinuously.

[0030] <Pressing process> Although not shown, the method of the present disclosure may further include pressing the laminate 1 before the roller conveyance. In particular, the pressing step may be performed before the drying step described above.

[0031] It is believed that the binder in the electrode active material layer that has undergone the pressing process is compressed, and therefore the flexibility of the electrode active material layer is reduced. Based on this assumption, it is particularly effective to apply the method of the present disclosure to the electrode active material layer that has undergone the pressing process.

[0032] The pressing method is not particularly limited, and a conventional method can be used.

[0033] The pressure of the press is not particularly limited, and can be appropriately set so that the density of the electrode active material layer has a desired value.

[0034] <Low temperature drying process> The method of the present disclosure may further include drying the electrode active material layer at a temperature lower than that in the drying step described above, prior to the pressing step. The drying temperature in this step may be 80° C. or higher, 90° C. or higher, or 100° C. or higher, and may be 140° C. or lower, 130° C. or lower, or 120° C. or lower.

[0035] <Temperature adjustment process> 2 and 3, the method of the present disclosure may further include adjusting the temperature of the laminate 1 after roller conveyance by at least one temperature adjustment mechanism 30. In particular, in the method of the present disclosure, low-temperature drying, pressing, heating (drying), roller conveyance, and temperature adjustment may be performed in this order. Note that these steps may be performed continuously or discontinuously.

[0036] There are no particular limitations on the temperature adjustment mechanism 30. For example, the temperature adjustment mechanism may be a temperature raising mechanism 31, a temperature lowering mechanism 32, or a combination thereof.

[0037] The temperature raising mechanism is not particularly limited, but may be, for example, a roller having a temperature adjusting function (temperature adjusting roller).

[0038] The number of temperature adjustment rollers is not particularly limited, and can be set appropriately from the viewpoints of suppressing cracking of the electrode active material layer and saving space.

[0039] When multiple temperature control rollers are used as the temperature raising mechanism, the temperature of the temperature control rollers arranged between the direction change roller and the last temperature control roller is not particularly limited, as long as the temperature of the last temperature control roller in the conveying direction of the laminate is the lowest. For example, the temperature of each roller can be set so that the temperature decreases sequentially from the direction change roller to the last temperature control roller. Also, for example, the temperature of a predetermined temperature control roller other than the last temperature control roller may be higher than the temperature of the direction change roller.

[0040] The temperature lowering mechanism is not particularly limited, and may be of a contact type or a non-contact type.

[0041] The contact-type temperature-lowering mechanism is not particularly limited, and may be, for example, a roller with a temperature-adjusting function (temperature-adjusting roller). When both the temperature-raising mechanism and the temperature-lowering mechanism are temperature-adjusting rollers, the temperature-adjusting roller can be used as a temperature-raising mechanism or a temperature-lowering mechanism by setting the temperature of the temperature-adjusting roller as the temperature-lowering mechanism lower than the temperature of the temperature-adjusting roller as the temperature-raising mechanism. When multiple temperature-adjusting rollers are used as temperature-lowering mechanisms, the temperature of the temperature-adjusting rollers arranged between the direction-changing roller and the last temperature-adjusting roller is not particularly limited, as long as the temperature of the last temperature-adjusting roller in the conveying direction of the laminate is the lowest. In particular, the temperature may be adjusted so that the temperature of the laminate is 50°C or lower when passing through or immediately after passing through the last temperature-adjusting roller.

[0042] The temperature regulating roller may be a free roller or a driven roller.

[0043] The diameter of the temperature adjustment roller is not particularly limited and can be set appropriately from the viewpoint of, for example, ease of suppressing cracking of the electrode active material layer, etc. This diameter may be the same as or different from the diameter of the direction changing roller, for example.

[0044] The angle at which the temperature-adjusting roller changes the conveying direction of the electrode active material layer is not particularly limited and can be set appropriately, for example, from the viewpoint of space saving. That is, for example, as illustrated in Figures 3 and 4, by folding back the laminate by the temperature-adjusting roller, the distance to the take-up reel can be shortened, which is advantageous from the viewpoint of space saving. This angle may be the same as or different from the angle in the case of the direction-changing roller.

[0045] The non-contact temperature-reducing mechanism is not particularly limited, and may be, for example, a cooling nozzle. In the present disclosure, a cooling nozzle refers to a nozzle capable of cooling an object by emitting a gas. When a cooling nozzle is used as the temperature-reducing mechanism, the temperature of the electrode active material layer, which is the object, can be adjusted, for example, by adjusting the flow rate of the gas. The gas is not particularly limited, and examples thereof include air and inert gas.

[0046] The temperature of the temperature-lowering mechanism can be set appropriately taking into consideration the temperature of the temperature-raising mechanism. That is, for example, in order to avoid excessive thermal stress due to rapid cooling, the temperature difference between the temperature-lowering mechanism and the immediately preceding temperature-raising mechanism may be set small.

[0047] The positional relationship between the temperature-raising mechanism and the temperature-lowering mechanism is not particularly limited, but for example, as illustrated in Figures 3 and 4, the temperature-raising mechanism and the temperature-lowering mechanism may be arranged alternately, or may not be arranged alternately.

[0048] The method of the present disclosure can also be applied to two electrode active material layers arranged on different surfaces of a current collector, i.e., a bipolar electrode stack. In this case, the electrode active material layer that is directly heated and the electrode active material layer arranged on the radially outer side of the direction-changing roller may be different, as particularly illustrated in FIG. 4. That is, for example, the method of the present disclosure can be applied to laser-heating a positive electrode active material layer and suppressing cracking of a negative electrode active material layer that has been heated by the laser-heating.

[0049] "battery" The battery of the present disclosure is manufactured by the method of manufacturing a battery of the present disclosure. In the battery of the present disclosure, cracking of the heat-treated electrode active material layer is suppressed.

[0050] The batteries of the present disclosure include an electrode stack and, optionally, an electrolyte layer.

[0051] In the context of the present disclosure, the term "electrode laminate" refers to a component that is a laminate of an electrode active material layer and a current collector and that can pass an electric current. That is, when the substrate layer in the method of the present disclosure is a current collector, the term "laminate" refers to an electrode laminate.

[0052] The bipolar battery of the present disclosure may be a liquid-based battery or a solid-state battery. In the context of the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as an electrolyte. Therefore, a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. Alternatively, the solid-state battery of the present disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as an electrolyte.

[0053] The battery of the present disclosure may be a primary battery or a secondary battery, particularly a lithium ion secondary battery.

[0054] The battery of the present disclosure may be a monopolar battery or a bipolar battery.

[0055] When the battery of the present disclosure is a monopolar battery, the "electrode laminate" may be a negative electrode laminate or a positive electrode laminate. For example, when the electrode laminate refers to a negative electrode laminate, the negative electrode laminate is a laminate of a negative electrode active material layer and a negative electrode current collector. When the electrode laminate refers to a positive electrode laminate, the positive electrode laminate is a laminate of a positive electrode active material layer and a positive electrode current collector. From the viewpoint of more effectively suppressing cracking of the electrode active material layer, the electrode laminate may particularly be a negative electrode laminate.

[0056] When the battery of the present disclosure is a bipolar battery, the "electrode laminate" may be a bipolar electrode laminate. The bipolar electrode laminate may have a negative electrode active material layer, a current collector, and a positive electrode active material layer, in this order. When the electrode laminate is a bipolar electrode laminate and laser heating is performed in the drying step, the positive electrode active material layer may be heated by irradiating it with a laser. Furthermore, in this case, the negative electrode active material layer may be arranged radially outward of the direction-changing roller. That is, the negative electrode active material layer, which has been heated by preheating from the laser-heated positive electrode active material layer, may be stretched by the direction-changing roller.

[0057] <Current collector> The current collector may be any known current collector for batteries, such as copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel foil, or carbon sheet.

[0058] When the battery of the present disclosure is a bipolar battery, the current collectors may include two different types of current collectors. In this case, the current collectors may be bonded to each other via a conductive adhesive layer or may be joined by pressing or the like. For example, the current collector on the negative electrode active material layer side may be copper foil, and the current collector on the positive electrode active material layer side may be aluminum foil.

[0059] The thickness of the current collector is not particularly limited, but may be 1 μm to 300 μm, 5 μm to 200 μm, or 10 μm to 100 μm. When the current collector has two types of current collectors bonded to each other via a conductive adhesive layer, the total thickness of the layers may be in the above range.

[0060] The size of the current collector is not particularly limited, and can be set appropriately taking into consideration, for example, the desired capacity of the battery.

[0061] The shape of the current collector is not particularly limited, but may be, for example, a quadrilateral such as a rectangle.

[0062] <Electrode active material layer> The electrode active material layer includes an electrode active material and a binder, and may optionally include a conductive additive and other components. In the present disclosure, the "electrode active material layer" may be a "negative electrode active material layer" or a "positive electrode active material layer."

[0063] The electrode active material layer can be formed from an electrode mixture slurry.

[0064] In the present disclosure, the term "composite" refers to a composition that can constitute an electrode active material layer, etc., either as it is or by further containing other components. In the present disclosure, the term "composite slurry" refers to a slurry that contains a dispersion medium in addition to the "composite" and that can be applied and dried to form an electrode active material layer, etc.

[0065] The thickness of the electrode active material layer is not particularly limited and may be 10 μm or more and 500 μm or less, 100 μm or more and 450 μm or less, or 200 μm or more and 400 μm or less.

[0066] The size of the electrode active material layer is not particularly limited, and can be set appropriately taking into consideration, for example, the desired capacity of the battery.

[0067] The shape of the electrode active material layer is not particularly limited, but may be, for example, a quadrangle such as a rectangle.

[0068] (electrode active material) The electrode active material is not particularly limited. In the present disclosure, the "electrode active material" can be used as both a "negative electrode active material" and a "positive electrode active material."

[0069] The negative electrode active material is not particularly limited as long as it has a lower potential than the positive electrode active material. When the electrode laminate of the present disclosure is an electrode laminate for a lithium ion secondary battery, examples of the negative electrode active material include carbonaceous materials such as graphite (artificial graphite, natural graphite), resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; metal-based materials mainly composed of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, and aluminum alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; and Li4Ti5O 12 and lithium alloys such as Li-Si alloys, Li-Sn alloys, Li-Al alloys, Li-Ga alloys, Li-Mg alloys, and Li-In alloys. These negative electrode active materials may be used singly or in combination of two or more.

[0070] The content of the negative electrode active material in the negative electrode mixture as the electrode mixture is not particularly limited, but may be 50 mass % or more, 70 mass % or more, 90 mass % or more, or 95 mass % or more.

[0071] The negative electrode active material may be in the form of particles, for example.

[0072] The positive electrode active material is not particularly limited as long as it has a more noble potential than the negative electrode active material. When the electrode laminate of the present disclosure is an electrode laminate for a lithium ion secondary battery, examples of the positive electrode active material include lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), lithium manganese oxide (LiMnO), solid solution oxide (LiMnO-LiMO (M=Co, Ni, etc.)), lithium nickel manganese oxide (LiNi 1 / 2 Mn 1 / 2 O2), lithium nickel cobalt manganese oxide (LiNi 1 / 3 Mn 1 / 3 Co 1 / 3Examples of the cathode active materials that can be used include composite oxides such as lithium phosphate oxide (LiFePO4), olivine-type lithium phosphate oxide (LiFePO4), and conductive polymers such as polyaniline and polypyrrole; sulfide-based cathode active materials such as LiS, CuS, Li-Cu-S compounds, TiS2, FeS, MoS2, Li-Mo-S compounds, Li-Ti-S compounds, and Li-VS compounds; and sulfur-based active materials such as sulfur-impregnated acetylene black, sulfur-impregnated porous carbon, and mixed powders of sulfur and carbon. These cathode active materials may be used alone or in combination of two or more.

[0073] The content of the positive electrode active material in the positive electrode mixture as the electrode mixture is not particularly limited, but may be 50 mass % or more, 70 mass % or more, 90 mass % or more, or 95 mass % or more.

[0074] The positive electrode active material may be in the form of particles, for example.

[0075] (binder) In the present disclosure, the binder can be stretched and spread in a flexible state, thereby suppressing cracking of the electrode active material layer.

[0076] The binder is not particularly limited, but when the battery of the present disclosure is a lithium ion secondary battery, examples of the binder include polyvinylidene fluoride (PVdF), polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyvinyl alcohol, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, etc. These binders may be used alone or in combination of two or more.

[0077] The content of the binder in the electrode mixture is not particularly limited, and can be set appropriately depending on the desired binding properties, etc.

[0078] (Conductive additive) The conductive additive is not particularly limited, but when the bipolar battery of the present disclosure is a lithium ion secondary battery, examples include graphites such as natural graphite and artificial graphite; carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; carbon fibers such as carbon nanotubes, conductive fibers such as metal fibers; metal powders such as aluminum powder; conductive whiskers such as zinc oxide whiskers and conductive potassium titanate whiskers; conductive metal oxides such as titanium oxide; organic conductive materials such as phenylene derivatives; etc. These conductive additives may be used alone or in combination of two or more.

[0079] The content of the conductive auxiliary agent in the electrode mixture is not particularly limited and can be set appropriately depending on the desired conductivity, etc.

[0080] (Other ingredients) The electrode mixture may contain components other than those described above. Examples of such components include dispersants. Examples of dispersants include carboxymethyl cellulose. [Example]

[0081] Example 1 and Comparative Examples 1 and 2 Example 1 A laminate consisting of a substrate layer and an electrode active material layer was laser-heated to 200°C. The temperature of the direction-changing roller was controlled to a temperature 30°C lower than the temperature of the laminate, and the laminate was conveyed by the roller so that the conveying direction of the laminate was changed by 45° along the direction-changing roller. The laminate was then wound around winding rollers of different diameters to determine the diameter of the winding roller at which cracks occurred in the electrode active material layer. The diameter of the winding roller was reduced in 5 mm increments starting from 90 mm. Note that cracks in the electrode active material layer on winding rollers with larger diameters indicate that the electrode active material layer is prone to cracking. As a result, cracks occurred in the electrode active material layer when a winding roller with a diameter of 35 mm was used. Note that when a similar evaluation was performed before laser heating, cracks occurred in the electrode active material layer when a winding roller with a diameter of 50 mm was used. This means that in Example 1, cracks were less likely to occur in the electrode active material layer after heating than before heating.

[0082] Comparative Example 1 The electrode active material layer was conveyed by rollers and evaluated in the same manner as in Example 1, except that the temperature of the direction-changing roller was not controlled. As a result, when a take-up roller with a diameter of 90 mm was used, cracks occurred in the electrode active material layer. That is, when a take-up roller with a diameter larger than that of Example 1 was used, cracks occurred in the electrode active material layer.

[0083] Comparative Example 2 The electrode active material layer was conveyed and evaluated in the same manner as in Example 1, except that the temperature of the direction-changing roller was controlled to a temperature 100°C lower than the temperature of the laminate. As a result, when a take-up roller with a diameter of 90 mm was used, cracks occurred in the electrode active material layer. That is, when a take-up roller with a diameter larger than that of Example 1 was used, cracks occurred in the electrode active material layer. [Explanation of symbols]

[0084] 1. Laminate 10 Heating section 20 Direction change roller 30 Temperature control mechanism 31 Heating mechanism 32 Temperature lowering mechanism

Claims

1. conveying the laminate, which has been heated to a temperature of 120° C. or higher and includes a base material layer and an electrode active material layer, by a roller such that the conveying direction of the laminate is changed by 45° or more along a direction-changing roller; and the direction-changing roller has a temperature adjusting function, and the temperature difference between the laminate and the direction-changing roller after heating is 80° C. or less; How batteries are manufactured.

2. The method of claim 1 , wherein the temperature difference is 50° C. or less.

3. Further comprising drying the electrode active material layer before the roller conveyance; and In the drying step, the laminate is heated to a temperature of 120°C or higher.

3. The method according to claim 1 or 2.

4. The method according to claim 3 , wherein the laminate is heated by a laser in the drying step.

5. The method of claim 1 or 2, further comprising adjusting the temperature of the laminate after the roller conveying with at least one temperature adjustment mechanism.

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