METHOD FOR MAKING A BATTERY

Abstract

A method of the present disclosure for manufacturing a battery comprises conveying a stack by means of rollers such that the conveying direction of the stack, which has been subjected to heating to a temperature of 120°C or more, is changed by 45° or more along a direction-change roller, wherein the stack comprises a base material layer and an electrode active material layer. Furthermore, in the method of the present disclosure, the temperature difference between the stack after heating and the direction-change roller is 80°C or less.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to a method for manufacturing a battery. 2. Description of the relevant state of the art

[0002] As disclosed in JP 2017 - 183 214A, JP 2016 - 103 402 A, JP 2008 - 147 114A, JP 2014 - 032 767 A and JP 2017 - 191 678 A, a technology has been developed which relates to the drying of an electrode active material layer configuring an electrode stack for a battery. Summary of the invention

[0003] At the time of battery manufacturing, it is desirable to reduce cracking in the electrode active material layer, which has undergone heat treatment for drying and the like.

[0004] One object of the present invention is to provide a method for manufacturing a battery which is capable of reducing cracking in an electrode active material layer which has been subjected to heat treatment.

[0005] The inventors of the present application and similar applications have determined that the above problem can be solved by the following means. Aspect 1

[0006] Aspect 1 of the invention relates to a method for manufacturing a battery, wherein the method comprises conveying a stack using rollers, such that the conveying direction of the stack, which has been subjected to heating to a temperature of 120°C or more, is changed by 45° or more along a direction change roller, wherein the stack has a base material layer and an electrode active material layer.

[0007] The direction change roller has a temperature adjustment function, and the temperature difference between the stack after heating and the direction change roller is 80°C or less. Aspect 2

[0008] In the procedure according to aspect 1, the temperature difference can be 50°C or less. Aspect 3

[0009] The process according to aspect 1 or 2 may further include drying the electrode active material layer before conveying using rollers.

[0010] Drying may involve heating the stack to a temperature of 120°C or more. Aspect 4

[0011] In the process according to aspect 3, drying can include heating the stack using a laser. Aspect 5

[0012] The method according to one of aspects 1 to 4 may further include adjusting the temperature of the stack after conveying with the aid of rollers by means of at least one temperature adjustment mechanism.

[0013] The method of the present invention for manufacturing a battery can reduce cracking in the electrode active material layer that has been subjected to heat treatment. Brief description of the illustrations

[0014] Features, advantages, and the technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying figures, in which the same symbols denote the same elements, and wherein: Fig. 1 is a schematic view which represents an example of a process for manufacturing a battery of the present disclosure; Fig. 2 is a schematic view which represents an example of the process for manufacturing a battery of the present disclosure; and Fig. 3 is a schematic view which represents an example of the process for manufacturing a battery of the present disclosure. Detailed description of embodiments

[0015] One embodiment of the present disclosure is described in detail below. It should be noted that the present disclosure is not limited to the embodiment described below and that various modifications can be made to it without deviating from the core of the disclosure. Method for manufacturing a battery

[0016] A method of the present disclosure for manufacturing a battery comprises conveying a stack using rollers such that the conveying direction of the stack, which has been heated to a temperature of 120°C or higher, is changed by 45° or more along a direction-change roller, wherein the stack comprises a base material layer and an electrode active material layer. Furthermore, in the method of the present disclosure, the direction-change roller has a temperature adjustment function, and the temperature difference between the stack after heating and the direction-change roller is 80°C or less.

[0017] The inventors of the present application and similar applications have considered that one of the reasons why cracking in an electrode active material layer, which has been heated to a predetermined temperature of 120°C or more, is easily induced is that moisture in the electrode active material layer is reduced, thus decreasing the flexibility of the electrode active material layer.

[0018] The inventors of the present application and similar applications have found that, during the manufacture of a battery, when the stack is conveyed by means of rollers such that the conveying direction of the stack, which has been heated to a temperature of 120°C or more and comprises the base material layer and the electrode active material layer, is changed by 45° or more along the direction-change roller at a temperature difference to the heated stack of a predetermined value or less, the cracking of the heat-treated electrode active material layer is reduced. The reason for this is estimated as follows, without this being bound to any theory.This means that, for example, when a stack at room temperature is redirected by 45° or more along the redirection roller, a number of electrode active materials bonded together by a binder within the stack are separated, leading to cracking in the electrode active material layer. In contrast, it is believed that the flexibility of the binder is increased in the electrode active material layer within the stack that has been heated to 120°C or more.It is considered that when the stack comprising the electrode active material layer undergoes a change of direction of 45° or more along the direction-change roller in this state, a moderate stress is exerted on the electrode active material layer, which contains the highly flexible binder. This allows the binder to expand and spread while the electrode active materials remain bonded to one another. Furthermore, using the direction-change roller at a temperature difference of a predetermined value or less with respect to the heated electrode active material layer, it is considered that the binder can effectively maintain a state of high flexibility. Consequently, it is considered that cracking in the electrode active material layer is reduced.

[0019] The following describes the process for manufacturing an electrode according to the present disclosure with reference to the illustrations. It should be noted that the dimensions in the illustrations do not reflect the actual dimensions.

[0020] It should be noted that the Fig. Figures 1 to 3 are schematic views illustrating an aspect in which an electrode active material layer is wound from an unwinding coil 41 onto a winding coil 42 by means of heating, conveying with the aid of rollers and temperature adjustment in a suitable manner. Step of conveying using rollers

[0021] As in Fig. As illustrated by example in Figure 1, the method of the present disclosure comprises conveying a stack 1 by means of rollers such that the conveying direction of the stack 1, which has been subjected to heating to a temperature of 120°C or more, is changed by 45° or more along a direction-change roller 20, wherein the stack 1 comprises a base material layer and an electrode active material layer. If an angle for changing the conveying direction of the stack lies within the aforementioned range, cracking in the electrode active material layer can be effectively reduced.

[0022] The heating temperature can be 130°C or more, 140°C or more, 150°C or more, 160°C or more, 170°C or more, 180°C or more, 190°C or more, or 200°C or more, and can be 300°C or less, 290°C or less, 280°C or less, 270°C or less, 260°C or less, or 250°C or less. If the heating temperature is within the aforementioned range, it is considered that a reduction in flexibility or the like, accompanied by a reduction in moisture in the electrode active material layer and deterioration of a binder, will be easily induced. Based on such an assessment, it is particularly effective to apply the method of the present disclosure to the electrode active material layer that has been subjected to heat treatment at a temperature within the aforementioned range.

[0023] The angle for changing the conveying direction of the stack can be 60° or more, 70° or more, 80° or more, 85° or more or 90° or more, and can 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.

[0024] In the method of the present disclosure, the direction-change roller has a temperature adjustment function, and the temperature difference between the stack after heating and the direction-change roller is 80°C or less. In such a configuration, the heated stack can be maintained at a predetermined temperature or higher, and thus cracking in the electrode active material layer can be effectively reduced. The temperature difference can be 0°C or more, 5°C or more, 10°C or more, 15°C or more, 20°C or more, 25°C or more, or 30°C or more, and can be 80°C or less, 70°C or less, 60°C or less, 55°C or less, 50°C or less, 45°C or less, 40°C or less, 35°C or less, or 30°C or less.

[0025] It should be noted that the stack temperature and the reversing roller temperature can be set such that the reversing roller temperature is lower. That is, the term "temperature difference" can refer to the temperature difference between "the stack temperature" and "the reversing roller temperature".

[0026] Furthermore, the term "temperature difference" can refer in particular to a temperature difference between the electrode active material layer and the direction change roller within the stack.

[0027] In the process of the present disclosure, the temperature of the stack at the time of the change of direction is not specifically limited and can be 40°C or more. If the temperature falls within the aforementioned range, cracking in the electrode active material layer can be effectively reduced. The temperature can be 50°C or more, 60°C or more, 70°C or more, 80°C or more, 90°C or more, or 100°C or more, and can be 150°C or less, 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less. The temperature can be suitably adjusted taking into account the softening temperature of the binder or the like. It should be noted that the term "temperature" can refer specifically to the temperature of the electrode active material layer within the stack.

[0028] The temperature of the stack can be monitored, for example, with a thermometer such as a temperature sensor. The thermometer could particularly be a non-contact radiation thermometer.

[0029] In the method of the present disclosure, the temperature of the direction-change roller can be adjusted based on the temperature of the heated stack. For example, the temperature of the direction-change roller can be controlled based on a signal input from a thermometer.

[0030] The diameter of the direction-change roller is not specifically limited and can be 35 mm or more, 40 mm or more, 45 mm or more, 50 mm or more, or 55 mm or more, and can 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. If the diameter of the direction-change roller falls within the aforementioned range, cracking in the electrode active material layer can be effectively reduced.

[0031] The circumferential speed of the direction-change roller is not limited in any particular way and can be appropriately adjusted taking into account the aspect of reducing cracking of the electrode active material layer, the aspect of ease of conveying and the like.

[0032] The base material layer in the process of the present disclosure is not specifically limited, and examples of the base material layer include a current collector and a separator sheet. For example, if the base material layer is a current collector, the stack subjected to the process of the present disclosure can be used directly to manufacture a battery. Furthermore, for example, if the base material layer is a separator sheet, the electrode active material layer within the stack subjected to the process of the present disclosure can be separated from the base material layer corresponding to the separator sheet, and an object obtained by transferring the electrode active material layer onto a current collector can be used to manufacture the battery. Drying step

[0033] The method of the present disclosure may further include drying the electrode active material layer prior to conveying by means of rollers, and the drying may include heating the stack 1 to a temperature of 120°C or more.

[0034] In the drying step, stack 1 can be heated, for example, by laser or infrared. From the perspective of effectively heating stack 1, the drying step can specifically include heating stack 1 with a laser. Furthermore, the drying step can incorporate blowing air in combination with this method. This air blowing can involve blowing hot air.

[0035] Drying can be carried out by a predetermined heating unit 10. It should be noted that heating and conveying using rollers can be carried out sequentially or non-sequentially. For example, in the Fig. One to three of the stacks are conveyed by rollers even during heating, so that heating and conveying by rollers are carried out sequentially. In contrast, the stack does not need to be conveyed or transported by rollers during heating, so that heating and conveying by rollers cannot be carried out sequentially. Press step

[0036] Although not shown, the method of the present disclosure may further include pressing the stack 1 before conveying it by means of rollers. In particular, the pressing step may be carried out before the drying step described above.

[0037] It is considered that in the electrode active material layer that has undergone the pressing step, the binder is compressed, thus reducing flexibility. Based on this assessment, it is particularly effective to apply the method of the present disclosure to the electrode active material layer that has undergone the pressing step.

[0038] The pressing process is not particularly restricted and can take a standard procedure.

[0039] The pressure of the pressing process is not particularly limited and can be adjusted appropriately so that the density of the electrode active material layer assumes a desired value. Low-temperature drying step

[0040] The method of the present disclosure may further comprise drying the electrode active material layer prior to the pressing step at a temperature lower than the temperature in the drying step described above. The drying temperature in this step may be 80°C or more, 90°C or more, or 100°C or more, and may be 140°C or less, 130°C or less, or 120°C or less. Temperature adjustment step

[0041] As in the Fig. 2 and Fig. As illustrated by example in Figure 3, the method of the present disclosure can further include adjusting the temperature of the stack 1 after conveying by means of rollers by means of at least one temperature adjustment mechanism 30. In particular, in the method of the present disclosure, the low-temperature drying, pressing, heating (drying), conveying by means of rollers or roller transport, and temperature adjustment can be carried out in the specified order. It should be noted that these steps can be carried out sequentially or non-sequentially.

[0042] The temperature adjustment mechanism 30 is not restricted in any particular way. For example, the temperature adjustment mechanism can be a temperature increase mechanism 31, a temperature decrease mechanism 32, or a combination thereof.

[0043] The temperature increase mechanism is not particularly restricted and can, for example, be a roller with a temperature adjustment function (a temperature adjustment roller).

[0044] The number of temperature adjustment rollers is not particularly limited and can be appropriately adjusted with regard to reducing cracking in the electrode active material layer and saving space.

[0045] When multiple temperature-adjustment rollers are used as the temperature-increasing mechanism, the temperature of the temperature-adjustment roller located between the direction-change roller and the last temperature-adjustment roller is not specifically limited, as long as the temperature of the last temperature-adjustment roller is the lowest in the conveying direction of the stack. For example, the roller temperatures can be set to decrease sequentially from the direction-change roller to the last temperature-adjustment roller. Furthermore, for example, the temperature of a predetermined temperature-adjustment roller, which differs from the last temperature-adjustment roller, can be higher than the temperature of the direction-change roller.

[0046] The temperature reduction mechanism is not particularly restricted and can be of the contact type or of the non-contact type.

[0047] The contact-type temperature reduction mechanism is not particularly restricted and can, for example, be a roller with a temperature adjustment function (a temperature adjustment roller). If both the temperature increase and temperature reduction mechanisms are temperature adjustment rollers, then if the temperature of the temperature adjustment roller serving as the temperature reduction mechanism is set lower than the temperature of the temperature adjustment roller serving as the temperature increase mechanism, the temperature adjustment roller can be used as either the temperature increase mechanism or the temperature reduction mechanism.When multiple temperature-adjusting rollers are used as the temperature-reducing mechanism, and provided that the temperature of the last temperature-adjusting roller is lowest in the conveying direction of the stack, the temperature of the temperature-adjusting roller located between the direction-change roller and the last temperature-adjusting roller is not specifically limited. In particular, the temperature can be adjusted such that the temperature of the stack at the time of passage through the last temperature-adjusting roller, or immediately after passage, is 50°C or less.

[0048] The temperature adjustment roller can be a free roller or a drive roller.

[0049] The diameter of the temperature-adaptation roller is not specifically limited and can be suitably adjusted, for example, to reduce cracking in the electrode active material layer or similar objectives. For instance, its diameter can be the same as or different from the diameter of the direction-change roller.

[0050] Furthermore, the angle for changing the conveying direction of the electrode active material layer by the direction-change roller is not particularly limited and can be adjusted appropriately, for example, to save space. That is to say, for example, as in Fig. 2 and Fig. Figure 3 shows that when the stack is folded by the temperature adjustment roller, the distance to the take-up spool can be reduced, and this is effective from a space-saving point of view. For example, the angle can be the same as or different from the angle in the case of the direction-change roller.

[0051] The non-contact temperature reduction mechanism is not specifically limited and can, for example, be a cooling nozzle. It should be noted that in this disclosure, the term "cooling nozzle" refers to a nozzle capable of cooling an object by ejecting gas. When the cooling nozzle is used as the temperature reduction mechanism, the temperature of the electrode active material layer representing the object can be adjusted, for example, by modifying the gas flow rate. The gas is not specifically limited, and examples include air and inert gases.

[0052] The temperature of the temperature reduction mechanism can be appropriately adjusted taking into account the temperature of the temperature increase mechanism. For example, to avoid excessive stress due to thermal strain caused by rapid cooling, the temperature difference between the temperature reduction and temperature increase mechanisms can be reduced immediately upstream of the temperature reduction mechanism.

[0053] The positional relationship between the temperature increase mechanism and the temperature decrease mechanism is not particularly restricted, and, for example, as in Fig. 2 and Fig. Figure 3 shows an example where the temperature increase mechanism and the temperature decrease mechanism can be arranged alternately, but do not have to be arranged alternately.

[0054] The method of the present disclosure is also applicable to two electrode active material layers arranged on different surfaces of the current collector, that is, on a bipolar electrode stack. In this case, as in particular shown in Fig. Figure 3 shows by way of example that the electrode active material layer to be heated directly and the electrode active material layer arranged radially on the outside of the direction-change roller can be different. This means, for example, that the method of the present disclosure is applicable to heating a positive electrode active material layer by laser and to reducing cracking of a negative electrode active material layer that is heated due to the residual heat of the laser heating. battery

[0055] A battery according to the present disclosure is manufactured according to the process of manufacturing a battery according to the present disclosure. In the battery according to the present disclosure, cracking in the electrode active material layer, which has been subjected to heat treatment, is reduced.

[0056] The battery of the present disclosure comprises an electrode stack and may optionally include an electrolyte layer.

[0057] In the present disclosure, the term "electrode stack" refers to a stack consisting of an electrode active material layer and a current collector, and denotes a component through which a current can flow. That is, if the base material layer is the current collector in the method of the present disclosure, the term "stack" refers to the electrode stack.

[0058] The battery of the present disclosure can be a liquid-state battery or a solid-state battery. It should be noted that in the present disclosure, the term "solid-state battery" refers to a battery using at least one solid electrolyte as the electrolyte, and thus the solid-state battery can use a combination of a solid electrolyte and a liquid electrolyte as the electrolyte. Furthermore, the solid-state battery of the present disclosure can be a pure solid-state battery, that is, a battery using only one solid electrolyte as the electrolyte.

[0059] The battery of the present disclosure can be a primary battery or a secondary battery. In particular, the battery of the present disclosure can be a lithium-ion secondary battery.

[0060] The battery of the present disclosure can be a monopolar battery or a bipolar battery.

[0061] If the battery of the present disclosure is a monopolar battery, the “electrode stack” can be a negative electrode stack or a positive electrode stack. For example, if the electrode stack refers to the negative electrode stack, the negative electrode stack is a stack consisting of a negative electrode active material layer and a negative electrode current collector. If the electrode stack refers to the positive electrode stack, the positive electrode stack is a stack consisting of a positive electrode active material layer and a positive electrode current collector. From the perspective of a more effective reduction of cracking in the electrode active material layer, the electrode stack can, in particular, correspond to the negative electrode stack.

[0062] If the battery of the present disclosure is a bipolar battery, the "electrode stack" can be a bipolar electrode stack. The bipolar electrode stack can comprise a negative electrode active material layer, a current collector, and a positive electrode active material layer in the specified order. If the electrode stack is a bipolar electrode stack and laser heating is performed in the drying step, the positive electrode active material layer can be irradiated with a laser to heat it. Furthermore, in this case, the negative electrode active material layer can be arranged on the outside of the direction-change roller in the radial direction. That is, the negative electrode active material layer, which is heated by the residual heat from the positive electrode active material layer that has undergone laser heating, can be stretched by the direction-change roller. power collector

[0063] A commonly known current collector can be used as the current collector of the battery. Examples of current collectors include copper foil, copper alloy foil, nickel foil, aluminum foil, aluminum alloy foil, stainless steel foil, and carbon plate.

[0064] If the battery of the present disclosure is a bipolar battery, the current collector may comprise two types of current collectors that are different from each other. In this case, the current collectors may be arranged to adhere to one another via an electrically conductive adhesive layer, or they may be joined together by pressing or the like. For example, the current collector on the side of the negative electrode active material layer may be a copper foil, and the current collector on the side of the positive electrode active material layer may be an aluminum foil.

[0065] The thickness of the current collector is not specifically limited and can be 1 µm or more and 300 µm or less, 5 µm or more and 200 µm or less, or 10 µm or more and 100 µm or less. If the current collector comprises two types of current collectors, which are arranged to adhere to each other via the electrically conductive adhesive layer, the sum of the thicknesses of the respective layers can fall within the aforementioned range.

[0066] The size of the current collector is not particularly limited and can be adjusted appropriately, for example, taking into account a desired battery capacity or the like.

[0067] The shape of the current collector is not particularly restricted and can, for example, have a square shape, such as a rectangular shape. Electrode active material layer

[0068] The electrode active material layer contains an electrode active material and a binder and may contain an electrically conductive additive and optionally other components. In the present disclosure, the “electrode active material layer” can be a “negative electrode active material layer” or a “positive electrode active material layer”.

[0069] The electrode active material layer can be formed from a slurry of electrode mixture materials.

[0070] It should be noted that in the present disclosure, the term "mixture material" refers to a composition capable of configuring the electrode active material layer or the like as it is, or by further containing other components. Furthermore, in the present disclosure, the term "mixture material slurry" refers to a slurry that, in addition to the "mixture material," contains a dispersion medium and is thereby capable of forming the electrode active material layer or the like by application and drying of the mixture material slurry.

[0071] The thickness of the electrode active material layer is not specifically limited. The thickness of the electrode active material layer can 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.

[0072] The size of the electrode active material layer is not particularly limited and can be adjusted appropriately, for example, taking into account the desired battery capacity or the like.

[0073] The shape of the electrode active material layer is not particularly restricted and can, for example, be a square shape, such as a rectangular shape. Electrode active material

[0074] The electrode active material is not specifically restricted. In the present disclosure, the “electrode active material” can be any “negative electrode active material” or a “positive electrode active material”.

[0075] The negative electrode active material is not specifically restricted, as long as it is a substance exhibiting a lower potential compared to the positive electrode active material. If the electrode stack of the present disclosure is an electrode stack for a lithium-ion secondary battery, examples of the negative electrode active material include: carbon-containing materials such as graphite (artificial and natural graphite), resinous carbon, carbon fibers, activated carbon, hard carbon, and soft carbon; metal-based materials primarily composed of tin, a tin alloy, silicon, a silicon alloy, gallium, a gallium alloy, indium, an indium alloy, aluminum, an aluminum alloy, and the like; electrically conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; and lithium-titanium complex oxides such as Li₄Ti₅O₆. 12; and lithium alloys, such as a Li-Si alloy, a Li-Sn alloy, a Li-Al alloy, a Li-Ga alloy, a Li-Mg alloy, and a Li-In alloy. One type of negative electrode active material can be used alone, or two or more types of negative electrode active materials can be used in combination.

[0076] The content of the negative electrode active material in the negative electrode mixture material, which serves as the electrode mixture material, is not specifically limited and may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more.

[0077] The shape of the negative electrode active material can, for example, be a particle shape.

[0078] The positive electrode active material is not specifically restricted, as long as it is a substance with a higher potential compared to the negative electrode active material. If the electrode stack of the present disclosure is an electrode stack for a lithium-ion secondary battery, examples of the positive electrode active material that can be used include: mixed oxides, such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), a mixed crystal oxide (Li2MnO3-LiMO2 (M = Co, Ni, or the like)), and lithium nickel manganese oxide (LiNi). 1 / 2 Mn 1 / 2 O2), a lithium nickel manganese cobalt oxide (LiNi 1 / 3 Mn 1 / 3 Co 1 / 3O2), an olivine-type lithium phosphorus oxide (LiFePO4); electrically conductive polymers, such as polyaniline and polypyrrole; sulfide-based positive electrode active materials, such as a Li2S, CuS, or Li-CuS compound, a TiS2, FeS, MoS2, or Li-MoS compound, a Li-TiS compound, and a Li-VS compound; and materials using sulfur as an active material, such as sulfur-impregnated acetylene black, sulfur-impregnated porous carbon, and mixed powders comprising sulfur and carbon. One type of positive electrode active material can be used alone, or two or more types of positive electrode active materials can be used in combination.

[0079] The content of the positive electrode active material in the positive electrode mixture, which serves as the electrode mixture, is not specifically limited and may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more.

[0080] The shape of the positive electrode active material can, for example, correspond to a particle shape. binder

[0081] In the present disclosure, crack formation in the electrode active material layer can be reduced by expansion and spreading of the binder in a state of flexibility.

[0082] The binder is not specifically limited, and if 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, polyamide-imide, 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, and carboxymethylcellulose. One type of binder may be used alone, or two or more types of binders may be used in combination.

[0083] The binder content in the electrode mixture material is not specifically limited and can be adjusted according to the desired bonding performance or the like. Electrically conductive aid

[0084] The electrically conductive auxiliary is not specifically limited, and if the battery of the present disclosure is a lithium-ion secondary battery, examples of the electrically conductive auxiliary include: graphites, such as natural graphite and synthetic graphite; carbon blacks, such as acetylene black, Ketjen black, canal black, furnace black, lamp black, and thermal black; electrically conductive fibers, such as carbon fibers, such as carbon nanotubes, and metal fibers; metal powders, such as aluminum powder; electrically conductive whiskers, such as zinc oxide whiskers and electrically conductive potassium titanate whiskers; electrically conductive metal oxides, such as titanium oxide; and organic electrically conductive materials, such as phenylene derivatives. One type of electrically conductive auxiliary may be used alone, or two or more types of electrically conductive auxiliary may be used in combination.

[0085] The content of the electrically conductive auxiliary material in the electrode mixture is not specifically limited and can be adjusted according to the desired electrically conductive behavior or the like. Other components

[0086] The electrode mixture may contain components other than those listed above. Examples of components include a dispersant. Examples of dispersants include carboxymethylcellulose. Example 1 and comparative examples 1, 2. Example 1

[0087] A stack consisting of a base material layer and an electrode active material layer was heated to 200°C using a laser. The temperature of the direction-change roller was controlled to a temperature 30°C lower than the temperature of the stack, and the stack was conveyed by rollers such that its conveying direction was changed by 45° along the direction-change roller. The stack was then wound onto winding rollers of varying diameters, and the diameter at which cracking occurred in the electrode active material layer was determined. The diameter of the winding roller was reduced from 90 mm by 5 mm. It should be noted that the occurrence of cracking in the electrode active material layer on a winding roller with a large diameter indicates that the electrode active material layer is prone to cracking.Consequently, cracking in the electrode active material layer occurred when using a winding roller with a diameter of 35 mm. It should be noted that cracking in the electrode active material layer also occurred when using a winding roller with a diameter of 50 mm when a similar assessment was performed before laser heating. This means that in Example 1, the probability of cracking in the electrode active material layer occurring was lower after heating than before heating. Comparative example 1

[0088] The electrode-active material layer was conveyed using rollers and evaluated in the same way as in Example 1, except that the temperature of the direction-change roller was not controlled. As a result, cracking occurred in the electrode-active material layer when a winding roller with a diameter of 90 mm was used. That is, cracking occurred in the electrode-active material layer when a winding roller with a larger diameter than in Example 1 was used. Comparative example 2

[0089] The electrode active material layer was conveyed and evaluated using rollers in the same way as in Example 1, except that the temperature of the direction-change roller was controlled to be 100°C lower than the temperature of the stack. As a result, cracking occurred in the electrode active material layer when a 90 mm diameter winding roller was used. That is, cracking occurred in the electrode active material layer when a winding roller with a larger diameter than in Example 1 was used. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2017 - 183 214A

[0002] JP 2016 - 103 402 A

[0002] JP 2008 - 147 114A

[0002] JP 2014 - 032 767 A

[0002] JP 2017 - 191 678 A

[0002]

Claims

[1] Method for manufacturing a battery, wherein the method comprises conveying a stack by means of rollers such that the conveying direction of the stack, which has been subjected to heating to a temperature of 120°C or more, is changed by 45° or more along a direction-change roller, wherein the stack comprises a base material layer and an electrode active material layer, wherein the direction-change roller has a temperature adjustment function and the temperature difference between the stack after heating and the direction-change roller is 80°C or less. [2] Method according to claim 1, wherein the temperature difference is 50°C or less. [3] Method according to claim 1 or 2, further comprising drying the electrode active material layer prior to conveying by means of rollers, wherein the drying comprises heating the stack to a temperature of 120°C or more. [4] Method according to claim 3, wherein the drying comprises heating the stack by laser. [5] Method according to claim 1 or 2, further comprising adjusting the temperature of the stack by means of at least one temperature adjustment mechanism, after conveying by means of rollers.

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