Method for producing formed body for electrode

Abstract

This method for producing a formed body for an electrode comprises: a step of supplying an electrode material containing an electrode active material, a conductive auxiliary agent and an electrolyte onto a current collector foil being conveyed; and a step of forming an electrode material film by leveling the electrode material supplied onto the current collector foil by using a forming part. The forming part includes: a surface A that faces the current collector foil, has a distance from the current collector foil that gradually decreases toward the downstream side in the conveyance direction of the current collector foil, and is closest to the current collector foil; and a surface B that is positioned on the upstream side in the conveyance direction of the current collector foil with respect to the surface A of the forming part. An angle θ1 formed between the surface A and the conveyance direction of the current collector foil of the forming part and an angle θ2 formed between the surface B and the horizontal surface satisfy Expression 1.　Expression 1: 0° < θ1 < θ2 ≤ 90°

Description

Method for manufacturing electrode molded body

[0001] The present disclosure relates to a method for producing a molded body for an electrode.

[0002] Quasi-solid-state batteries have the advantage that the electrode layer can be formed without a drying process by mixing the electrolyte with the electrode active material and conductive additive in advance.Furthermore, because they do not contain binders, they can be said to be batteries with excellent recyclability.

[0003] Patent Document 1 discloses an electrochemical cell including a positive current collector having a first surface and a second surface, a semi-solid cathode disposed only on the first surface of the positive current collector, a negative current collector having a first surface and a second surface, a semi-solid anode disposed only on the first surface of the negative current collector, and a separator disposed between the first surface of the positive current collector and the first surface of the negative current collector.

[0004] U.S. Patent No. 6,277,633 discloses a method comprising continuously dispensing a semi-solid electrode slurry onto a current collector, separating the semi-solid electrode slurry into separate portions, and cutting the current collector to form finished electrodes.

[0005] Patent Document 3 discloses a squeegee that uniformly levels the thickness of a powder layer made of powder supplied to a substrate by moving the squeegee relative to the substrate in a fixed direction while forming a desired gap with the substrate, the squeegee having a first portion that vibrates in contact with the powder upstream of the direction of relative movement of the substrate relative to the squeegee, and a second portion that vibrates in contact with the powder downstream of the direction of relative movement of the substrate relative to the squeegee, wherein the vibration direction of the first portion is different from the vibration direction of the second portion.

[0006] Patent Document 4 discloses a lithium ion secondary battery including a positive electrode forming step of forming a positive electrode, a negative electrode forming step of forming a negative electrode, and a battery constructing step of constructing a lithium ion secondary battery using the positive electrode and the negative electrode, the positive electrode forming step including the following steps: preparing a positive electrode current collector made of aluminum or an aluminum alloy and having a surface ten-point height difference (Rz) of 0.6 μm≦Rz≦2.8 μm; preparing positive electrode granulated particles containing at least positive electrode active material particles and a binder, the positive electrode granulated particles having a mean particle size (D50) of 50 μm≦D50≦100 μm; supplying the positive electrode granulated particles to the surface of the positive electrode current collector; and applying a squeegee member to the positive electrode granulated particles supplied to the surface of the positive electrode current collector to smooth it out; and the negative electrode forming step includes the following steps: preparing a positive electrode current collector made of copper or a copper alloy and having a surface ten-point height difference (Rz) of 1.02 μm≦Rz≦3. The present invention discloses a method for manufacturing a lithium-ion secondary battery, the method including: preparing a negative electrode current collector having a particle size of 15 μm; preparing negative electrode granulated particles containing at least negative electrode active material particles and a binder, the negative electrode granulated particles having an average particle size (D50) of 50 μm≦D50≦100 μm; supplying the negative electrode granulated particles to a surface of the negative electrode current collector; and applying a squeegee member to the negative electrode granulated particles supplied to the surface of the negative electrode current collector to level them.

[0007] Patent Document 1: JP-T-2017-533548 A Patent Document 2: JP-T-2021-530829 A Patent Document 3: WO 2022 / 196363 Patent Document 4: JP-A-2016-119260

[0008] The problem to be solved by the present disclosure is to provide a method for producing an electrode molded body that suppresses the electrode material from rising up into a molded portion and results in an electrode material film with excellent continuity.

[0009] Means for solving the above problems include the following aspects: <1> A method for manufacturing a molded body for an electrode, comprising: a step of supplying an electrode material containing an electrode active material, a conductive additive, and an electrolyte solution onto a current collector foil being transported; and a step of using a forming unit to level the electrode material supplied onto the current collector foil and form an electrode material film, wherein the forming unit faces the current collector foil, the distance from the current collector foil gradually decreases toward the downstream side in the transport direction of the current collector foil, and the forming unit has a surface A that is closest to the current collector foil, and a surface B of the forming unit that is located more upstream than surface A of the forming unit in the transport direction of the current collector foil, and an angle θ1 formed by surface A of the forming unit and the transport direction of the current collector foil, and an angle θ2 formed by surface B and a horizontal plane satisfy the following formula 1: 0 degrees<θ1<θ2≦90 degrees Equation 1 <2> The method for producing a molded article for an electrode according to <1>, wherein an angle θ3 formed by a surface C of the molding section, which is located downstream of surface A in the direction of conveyance of the current collector foil, and a horizontal plane satisfies the following equation 3: 30 degrees≦θ3<180 degrees−θ1 Equation 3 <3> The method for producing a molded article for an electrode according to <2>, wherein the molding section is constituted by a first molding member having surface A and surface C, and a second molding member having surface B. <4> The method for producing a molded article for an electrode according to <3>, wherein the first molding member and the second molding member are provided 0.01 mm to 10 mm apart, and wherein, in the step of molding the electrode material film, the first molding member vibrates and the second molding member is in a non-vibrating state. <5> The method for producing a molded article for an electrode according to any one of <1> to <4>, wherein a contact angle of surface B with respect to the electrolyte is lower than a contact angle of the current collector foil with respect to the electrolyte. <6> The method for producing an electrode molded article according to any one of <1> to <5>, wherein the θ1 satisfies the following formula 1-1: 5 degrees≦θ1≦30 degrees Formula 1-1 <7> The method for producing an electrode molded article according to any one of <1> to <6>, wherein the θ2 satisfies the following formula 2-1: θ1+5 degrees≦θ2≦90 degrees Formula 2-1 <8> The method for producing an electrode molded article according to <2>, wherein the θ3 satisfies the following formula 3-1: 90 degrees<θ3<180 degrees−θ1 Formula 3-1

[0010] According to the present disclosure, it is possible to provide a method for manufacturing an electrode molded body that suppresses the electrode material from rising up onto a molded portion and that results in an electrode material film with excellent continuity.

[0011] Fig. 1 is a schematic cross-sectional view showing an example of a conventional film-forming apparatus; Fig. 2 is a schematic cross-sectional view showing an example of a film-forming apparatus that can be suitably used in the method for manufacturing an electrode molded article according to the present disclosure; Fig. 3 is a schematic cross-sectional view showing another example of a film-forming apparatus that can be suitably used in the method for manufacturing an electrode molded article according to the present disclosure; Fig. 4 is a schematic cross-sectional view showing yet another example of a film-forming apparatus that can be suitably used in the method for manufacturing an electrode molded article according to the present disclosure; Fig. 5 is a schematic cross-sectional view showing yet another example of a film-forming apparatus that can be suitably used in the method for manufacturing an electrode molded article according to the present disclosure.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments. The following embodiments may be modified as appropriate within the scope of the present disclosure.

[0013] When describing embodiments of the present disclosure with reference to the drawings, explanations of overlapping components and symbols in the drawings may be omitted. Components indicated by the same symbols in the drawings are the same components. The dimensional ratios in the drawings do not necessarily represent the actual dimensional ratios.

[0014] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the lower and upper limits, respectively. In the numerical ranges described in stages in the present disclosure, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the examples.

[0015] In the present disclosure, when a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0016] In the present disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0017] In the present disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.

[0018] In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.

[0019] In this disclosure, "solid content" means components other than the solvent.

[0020] <Method for manufacturing electrode molded body> A method for manufacturing an electrode molded body according to the present disclosure includes the steps of: supplying an electrode material containing an electrode active material, a conductive additive, and an electrolyte solution onto a current collector foil being conveyed; and smoothing the electrode material supplied onto the current collector foil using a forming unit to form an electrode material film, wherein the forming unit faces the current collector foil, the distance from the current collector foil gradually decreases toward the downstream side in the conveyance direction of the current collector foil, and the forming unit has a surface A closest to the current collector foil, and a surface B of the forming unit located more upstream of surface A in the conveyance direction of the current collector foil, and an angle θ1 formed by surface A of the forming unit with the conveyance direction of the current collector foil, and an angle θ2 formed by surface B with a horizontal plane satisfy the following formula 1: 0 degrees < θ1 < θ2 ≦ 90 degrees Formula 1

[0021] In conventional methods for manufacturing electrode molded bodies, when the electrode material is leveled by a molding part such as a blade, the electrode material does not adhere to the current collector foil as a film, but rises up onto the surface of the molding part located upstream in the current collector foil conveyance direction, resulting in discontinuous formed film and film failure. After investigations, the inventors discovered that film failure caused by the electrode material rising up is due to the electrode material being supplied to the molding part being made less viscous by vibration and pressure, and flowing toward the surface of the molding part where the pressure is lower than the meniscus, and also due to the three-way relationship between the molding part, the electrode material, and the current collector film, which makes it difficult for the electrode material to adhere to the current collector foil. In the method for manufacturing an electrode molded body according to the present disclosure, the molding section faces the current collector foil, the distance from which gradually decreases toward the downstream side in the conveying direction of the current collector foil, and has a surface A that is closest to the current collector foil, and a surface B of the molding section that is located upstream of surface A in the conveying direction of the current collector foil, and the angle θ1 between surface A of the molding section and the conveying direction of the current collector foil, and the angle θ2 between surface B and a horizontal plane satisfy the above formula 1, thereby suppressing the electrode material from rising up and riding onto the surface of the molding section that is located upstream in the conveying direction of the current collector foil, and increasing the force in the direction pressing the electrode material and the current collector foil together, thereby suppressing the electrode material from rising up onto the molding section, and it is estimated that the resulting electrode material film has excellent continuity.

[0022] The method for producing an electrode molded body according to the present disclosure will be described in detail below.

[0023] (Step of forming an electrode material film) The manufacturing method of an electrode molded body according to the present disclosure includes a step of leveling an electrode material supplied onto a current collecting foil using a forming unit to form an electrode material film. The forming unit faces the current collecting foil, the distance from which gradually decreases toward the downstream side in the conveyance direction of the current collecting foil, and has a surface A closest to the current collecting foil, and a surface B of the forming unit located upstream of surface A in the conveyance direction of the current collecting foil, and an angle θ1 between surface A of the forming unit and the conveyance direction of the current collecting foil, and an angle θ2 between surface B and a horizontal plane satisfy the following formula 1: 0 degrees < θ1 < θ2 ≦ 90 degrees Formula 1

[0024] The reference direction for θ1 is the conveyance direction of the current collector foil, and the reference plane for θ2 and θ3 (described later) is a horizontal plane that is perpendicular to the direction of gravity.

[0025] The angle θ1 satisfies the above formula 1, and from the viewpoint of the continuity and film thickness uniformity of the electrode material film, it preferably satisfies the following formula 1-0, more preferably satisfies the following formula 1-1, and particularly preferably satisfies the following formula 1-2: 2.5 degrees≦θ1≦45 degrees Formula 1-0 5 degrees≦θ1≦30 degrees Formula 1-1 10 degrees≦θ1≦20 degrees Formula 1-2

[0026] The angle θ2 satisfies the above formula 1, and from the viewpoint of the continuity and film thickness uniformity of the electrode material film, it is preferable to satisfy the following formula 2-1, more preferably to satisfy the following formula 2-2, even more preferably to satisfy the following formula 2-3, and particularly preferably to satisfy the following formula 2-4: θ1+5 degrees≦θ2≦90 degrees Formula 2-1 θ1+10 degrees≦θ2≦90 degrees Formula 2-2 θ1+30 degrees≦θ2≦90 degrees Formula 2-3 θ1+30 degrees≦θ2≦80 degrees Formula 2-4 Furthermore, from the viewpoint of the continuity and film thickness uniformity of the electrode material film, the angle θ2 is preferably an angle smaller than θ3, which will be described later.

[0027] The angle θ3 formed by a surface C of the shaped portion located downstream of surface A in the conveying direction of the current collecting foil and a horizontal plane preferably satisfies the following formula 3-0, more preferably satisfies the following formula 3, and particularly preferably satisfies the following formula 3-1. When θ3 is in the above-mentioned manner, the electrode material is prevented from rising up onto the surface of the shaped portion located downstream in the conveying direction of the current collecting foil, resulting in better continuity and film thickness uniformity of the electrode material film. 20 degrees≦θ3<180 degrees−θ1 Formula 3-0 30 degrees≦θ3<180 degrees−θ1 Formula 3 90 degrees<θ3<180 degrees−θ1 Formula 3-1 Furthermore, from the viewpoint of continuity and film thickness uniformity of the electrode material film, θ3 is preferably greater than 20 degrees and less than 170 degrees, more preferably greater than 60 degrees and less than 160 degrees, and particularly preferably greater than 90 degrees and less than 150 degrees. Furthermore, from the viewpoint of the continuity and thickness uniformity of the electrode material film, it is preferable that the above θ3 satisfies the following formula 4: θ1<θ2<θ3 Formula 4

[0028] Each of the surfaces A, B, and C of the shaping portion may be a flat surface, a curved surface, or a polygonal surface formed by connecting a plurality of surfaces. In the present disclosure, when the surface A, B, or C is a curved surface or a polygonal surface, θ1 to θ3 are defined as angles formed between a straight line connecting the start point and the end point of the curved surface or polygonal surface and the conveyance direction of the current collector foil or a horizontal plane in a cross section of the current collector foil in the conveyance direction.

[0029] The shaped portion may consist of one member or two or more members as long as it satisfies the above formula 1, but from the viewpoint of the continuity of the electrode material film and the uniformity of the film thickness, it is preferably composed of one or two members, more preferably two members, and particularly preferably composed of a first shaped member having a surface A and a surface C and a second shaped member having a surface B. Note that the above members are members that constitute the above surface A, surface B, and surface C described below, and it goes without saying that, for example, fixing members that fix the shaped portion and fixing members that fix each member, etc. are not included in the number of the above members.

[0030] From the viewpoint of the continuity and thickness uniformity of the electrode material film, the forming part is preferably vibrated, and the vibration is more preferably ultrasonic vibration. Furthermore, when the forming part is made of two or more members, it is preferable that the member having at least surface A is vibrated.

[0031] The vibration direction of the forming section is not particularly limited. The vibration of the forming section may be continuous or intermittent. The amplitude of the vibration of the forming section is preferably, for example, 0.1 μm to 200 μm, more preferably 1 μm to 100 μm, and even more preferably 1 μm to 10 μm. The frequency of the vibration of the forming section is preferably, for example, 50 Hz to 1 MHz, and more preferably 5 kHz to 500 kHz. The frequency of the vibration of the forming section may include multiple frequencies. For example, the vibration of the forming section may be such that multiple frequency peaks are detected, such as 150 kHz, 300 kHz, and 450 kHz. The vibration amplitude and frequency can be measured using an acceleration sensor or a vibration measuring device. When multiple frequency peaks are detected during measurement of the vibration of the forming section, the smallest frequency is defined as the "frequency of the vibration of the forming section," and the amplitude at this frequency is defined as the "amplitude of the vibration of the forming section." For example, if multiple frequency peaks such as 150 kHz, 300 kHz, and 450 kHz are detected for the vibration of the molding part, 150 kHz is defined as the "frequency of the vibration of the molding part," and the amplitude at the frequency of 150 kHz is defined as the "amplitude of the vibration of the molding part."

[0032] Furthermore, when the molded body is constituted by a first molding member having the surface A and the surface C and a second molding member having the surface B, from the viewpoint of the continuity and film thickness uniformity of the electrode material film, it is preferable that the first molding member and the second molding member are spaced apart by 0.001 mm to 25 mm, more preferably by 0.01 mm to 10 mm, and particularly preferably by 0.01 mm to 0.5 mm. Furthermore, from the viewpoint of the continuity and film thickness uniformity of the electrode material film, it is preferable that the first molding member and the second molding member are spaced apart by 0.01 mm to 10 mm, and that in the step of molding the electrode material film, the first molding member vibrates and the second molding member is in a non-vibrating state.

[0033] The material of the molded portion is not particularly limited and may be any known material, but stainless steel is preferred from the viewpoints of wear resistance and processability. Furthermore, it is preferable that the electrode material does not easily adhere to the contact portion between the molded portion and the electrode material. For example, it is preferable that at least the surface of the molded portion exhibits mold-releasability. For example, the molded portion may be made of a fluororesin such as polytetrafluoroethylene (PTFE) or a resin such as polyether ether ketone (PEEK), or a metal such as stainless steel, aluminum, iron, or cemented carbide, or may be made of ceramic. Furthermore, to impart mold-releasability to the surface, the molded portion may have a surface layer exhibiting mold-releasability (e.g., a surface layer containing a fluororesin, or a surface layer containing silicon-based particles and a resin). Furthermore, from the viewpoint of improving wear resistance, the molded portion may have a high-hardness coating such as titanium oxide, titanium nitride (TiN), or tungsten carbide on a metal or ceramic blade body.

[0034] Furthermore, it is preferable that the contact angle of surface B of the molded part with the electrolyte be lower than the contact angle of the current collecting foil with the electrolyte. In this embodiment, swelling of the electrode material is suppressed, adhesion of the electrode material to the current collecting foil is improved, and the continuity and film thickness uniformity of the electrode material film are superior. There are no particular limitations on the method for adjusting the contact angle of surface B of the molded part with the electrolyte, and known surface treatment methods can be used.

[0035] In the present disclosure, the contact angle of the electrolyte on the surface to be measured is measured as follows: When a droplet of the electrolyte comes into contact with the surface to be measured (for example, surface B), the angle formed between the tangent of the droplet and the surface is measured using a DMo-902 manufactured by Kyowa Interface Science Co., Ltd.

[0036] In the step of forming the electrode material film, the thickness of the formed electrode material film may be selected as appropriate as desired, but is preferably smaller than the thickness of the electrode material supplied onto the current collector foil in the supplying step, and is preferably 10 μm to 5,000 μm, more preferably 20 μm to 1,000 μm, and particularly preferably 70 μm to 500 μm.

[0037] The conveying speed of the current collector foil provided with the electrode material in the step of forming the electrode material film is not particularly limited and can be selected appropriately as desired. Furthermore, even if the conveying speed is constant, it may be changed appropriately depending on the conditions of the formation of the electrode material film, etc.

[0038] Furthermore, as a conveying means for conveying the current collecting foil provided with the electrode material, a known conveying means can be used, specifically, for example, a belt conveyor, a linear motion guide, a cross roller table, or the like.

[0039] The molding section will be further described with reference to the drawings.

[0040] FIG. 1 is a schematic cross-sectional view showing an example of a conventional film forming apparatus. The film forming apparatus 10 shown in FIG. 1 has a blade-shaped forming unit 12, and an electrode material 14 provided on a current collector foil 18 is conveyed in a conveying direction CD by a conveying means 16. In the forming unit 12 shown in FIG. 1, the electrode material 14 rises, causing film defects such as discontinuous portions in the formed electrode material film 22. The forming unit 12 shown in FIG. 1 vibrates, and this vibration creates low-viscosity regions 20 where the viscosity of the electrode material 14 is reduced. However, similar film defects can occur even when the forming unit 12 is not vibrating.

[0041] Fig. 2 is a schematic cross-sectional view showing an example of a film forming apparatus suitable for use in the manufacturing method of an electrode molded body according to the present disclosure. The film forming apparatus 10 shown in Fig. 2 has a forming unit 12, and an electrode material 14 provided on a current collector foil 18 is conveyed in a conveying direction CD by a conveying means 16. The forming unit 12 in Fig. 2 faces the current collector foil 18, and the distance from the current collector foil 18 gradually decreases toward the downstream side in the conveying direction CD of the current collector foil 18. The forming unit 12 has a surface A closest to the current collector foil 18, a surface B located upstream of the surface A in the conveying direction CD of the current collector foil 18, and a surface C located downstream of the surface A in the conveying direction CD of the current collector foil 18, and the surfaces A, B, and C are configured from a single member. In addition, the angle θ1 between the surface A in the forming unit 12 shown in FIG. 2 and the conveyance direction CD of the current collector foil 18, the angle θ2 between the surface B in the forming unit 12 and the horizontal plane, and the angle θ3 between the surface C in the forming unit 12 and the horizontal plane satisfy the above formulas 1 and 3. In the cross section of the film forming device 10 shown in FIG. 2, the conveyance direction CD of the current collector foil 18 and the horizontal plane are the same direction. The angle between the conveyance direction CD and the surface direction of the horizontal plane in the cross section is preferably 0 degrees to 10 degrees, more preferably 0 degrees to 5 degrees, and particularly preferably 0 degrees. In the forming unit 12 shown in FIG. 2, the electrode material 14 is prevented from rising up on the upstream and downstream sides of the conveyance direction CD in the forming unit 12, and the formed electrode material film 22 is prevented from causing the above-mentioned film failure and has excellent continuity and film thickness uniformity.

[0042] 3 is a schematic cross-sectional view showing another example of another film forming apparatus suitable for use in the manufacturing method of an electrode molded body according to the present disclosure. The film forming apparatus 10 shown in FIG. 3 has a forming section composed of a first forming member 12A and a second forming member 12B, and an electrode material 14 provided on a current collector foil 18 is conveyed in a conveying direction CD by a conveying means 16. The forming section in FIG. 3 faces the current collector foil 18, and the distance from the current collector foil 18 gradually decreases toward the downstream side of the current collector foil 18 in the conveying direction CD of the current collector foil 18. The forming section has a surface A closest to the current collector foil 18, a surface B located upstream of the surface A in the conveying direction CD of the current collector foil 18 in the forming section, and a surface C located downstream of the surface A in the conveying direction CD of the current collector foil 18 in the forming section. The first forming member 12A has the surfaces A and C, and the second forming member 12B has the surface B. 3, the angle θ1 formed between the surface A of the forming unit 12 and the conveyance direction CD of the current collector foil 18, the angle θ2 formed between the surface B of the forming unit 12 and the horizontal plane, and the angle θ3 formed between the surface C of the forming unit 12 and the horizontal plane satisfy the above formulas 1 and 3. When the first forming member 12A shown in FIG. 3 vibrates, a low-viscosity region 20 is formed in which the viscosity of the electrode material 14 is reduced by the vibration.

[0043] Fig. 4 is a schematic cross-sectional view showing yet another example of a film forming apparatus suitable for use in the manufacturing method of an electrode molded body according to the present disclosure. The film forming apparatus 10 shown in Fig. 4 has a forming section composed of a first forming member 12A and a second forming member 12B, and an electrode material 14 provided on a current collector foil 18 is conveyed in a conveying direction CD by a conveying means 16. The first forming member 12A in Fig. 4 faces the current collector foil 18, and the distance from the current collector foil 18 gradually decreases toward the downstream side in the conveying direction CD of the current collector foil 18. The first forming member 12A has a surface A closest to the current collector foil 18 and a surface C located downstream of the surface A of the first forming member 12A in the conveying direction CD of the current collector foil 18. The second forming member 12B has a surface B located upstream of the surface A of the forming member 12 in the conveying direction CD of the current collector foil 18. The forming section in Fig. 4 is composed of the first forming member 12A having the surfaces A and C, and the second forming member 12B having the surface B. Furthermore, θ1 (not shown) and θ2 (not shown) in the forming portion shown in Figure 4 satisfy the above formula 1, and θ3 (not shown) satisfies the above formula 3. Note that the first forming member 12A shown in Figure 4 is vibrating, and the vibration causes a low-viscosity region 20 in which the viscosity of the electrode material 14 is reduced. Furthermore, the second forming member 12B is not vibrating and is in a vibration-free state. When the second forming member 12B is in a vibration-free state, the rising of the electrode material 14 is further suppressed, and the formed electrode material film 22 has better continuity and film thickness uniformity.

[0044] Fig. 5 is a schematic cross-sectional view showing yet another example of a film forming apparatus suitable for use in the manufacturing method of an electrode molded body according to the present disclosure. The film forming apparatus 10 shown in Fig. 5 has a forming section composed of a first forming member 12A and a second forming member 12B, and an electrode material 14 provided on a current collector foil 18 is conveyed in a conveying direction CD by a conveying means 16. The first forming member 12A in Fig. 5 faces the current collector foil 18, and the distance from the current collector foil 18 gradually decreases toward the downstream side in the conveying direction CD of the current collector foil 18. The first forming member 12A has a surface A closest to the current collector foil 18 and a surface C located downstream of the surface A of the first forming member 12A in the conveying direction CD of the current collector foil 18. The second forming member 12B has a surface B located upstream of the surface A of the first forming member 12A in the conveying direction CD of the current collector foil 18. The forming section in Fig. 5 is composed of the first forming member 12A having the surfaces A and C, and the second forming member 12B having the surface B. 5, θ1 (not shown) and θ2 (not shown) satisfy the above formula 1, and θ3 is an angle exceeding 90 degrees and satisfies the above formula 3. The first molding member 12A shown in FIG. 5 is vibrating, and the vibration causes a low-viscosity region 20 in which the viscosity of the electrode material 14 is reduced. The second molding member 12B is not vibrating and is in a non-vibrating state.

[0045] 3 to 5, the forming section composed of the first forming member 12A and the second forming member 12B suppresses the rise of the electrode material 14 on the upstream and downstream sides of the forming section in the conveying direction CD, and the formed electrode material film 22 is prevented from causing the above-mentioned film failure and has excellent continuity and film thickness uniformity. Furthermore, the first forming member 12A and the second forming member 12B in FIGS. 3 to 5 may be in contact with each other or may be spaced apart, but from the viewpoint of the continuity and film thickness uniformity of the electrode material film, it is preferable that they are spaced apart, and more preferably spaced apart by 0.01 mm to 10 mm.

[0046] (Step of supplying electrode material) The method for producing an electrode molded body according to the present disclosure includes a step of supplying an electrode material containing an electrode active material, a conductive additive, and an electrolyte onto the current collector foil being transported (also referred to as a "step of supplying electrode material").

[0047] In the step of supplying the electrode material, the electrode material is prepared in advance and then supplied onto the current collector foil. The method for preparing the electrode material is not particularly limited, and any known mixing means can be used. Examples of the mixing means include a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, and a disk mill.

[0048] The means for supplying the electrode material onto the current collector foil may be any supply means capable of supplying a required amount of electrode material onto the current collector foil. Examples of the supply means include means for intermittently or continuously supplying the electrode material onto the current collector foil (e.g., a hopper, a screw feeder, a disk feeder, a vibrating feeder, etc.). Furthermore, when supplying the electrode material onto the current collector foil, a regulating frame or a mesh frame may be used to ensure uniform application of the mixture.

[0049] The thickness of the electrode material supplied onto the current collector foil may be selected as desired, but is preferably thicker than the electrode material film to be formed. The thickness of the electrode material supplied onto the current collector foil is preferably 10 μm to 5,000 μm, more preferably 20 μm to 1,000 μm, and particularly preferably 70 μm to 500 μm.

[0050] [Current Collector Foil] The current collector foil is not particularly limited, and known current collector foils (positive electrode current collector foil and negative electrode current collector foil) can be used.

[0051] Examples of the positive electrode current collector foil include aluminum, aluminum alloy, stainless steel, nickel, and titanium. The positive electrode current collector foil is preferably aluminum or an aluminum alloy. The positive electrode current collector foil may be aluminum having a coating layer on its surface containing one or more of carbon, nickel, titanium, silver, gold, platinum, and vanadium oxide.

[0052] Examples of negative electrode current collector foils include aluminum, copper, copper alloys, stainless steel, nickel, and titanium. The negative electrode current collector foil is preferably aluminum, copper, a copper alloy, or stainless steel, and more preferably copper or a copper alloy. The negative electrode current collector foil may be copper or stainless steel having a coating layer on its surface containing one or more of carbon, nickel, titanium, silver, and lithium.

[0053] The current collector foil is preferably an aluminum foil (including an aluminum foil having the above-described coating layer on its surface) or a copper foil (including a copper foil having the above-described coating layer on its surface). Aluminum foil is usually used as a current collector foil for a positive electrode. Copper foil is usually used as a current collector foil for a negative electrode.

[0054] The current collector foil may be a laminate of a metal layer exemplified as the positive electrode current collector foil or the negative electrode current collector foil described above and a resin film. Examples of the resin film used in the laminate include polyethylene terephthalate (PET) film, polypropylene (PP) film, polyethylene (PE) film, cyclic olefin polymer (COP, COC) film, triacetyl cellulose (TAC) polyimide (PI) film, and polyamide (PA) film.

[0055] From the viewpoint of transportability, the thickness of the current collecting foil is preferably 3 μm or more, more preferably 5 μm or more, and particularly preferably 10 μm or more. From the viewpoint of flexibility and light weight, the thickness of the current collecting foil is preferably 100 μm or less, more preferably 70 μm or less, and particularly preferably 50 μm or less. Here, the thickness of the current collecting foil film is the arithmetic mean value of the thicknesses measured at three locations by cross-sectional observation. A known microscope (e.g., a scanning electron microscope) can be used for cross-sectional observation.

[0056] The size of the current collector foil is not limited, and may be determined depending on the size of the electrode molded body to be produced, the sizes of various members used in the production process, and the like.

[0057] The electrode material contains an electrode active material, a conductive additive, and an electrolyte, and may contain additives as needed.

[0058] [Electrode active material] The electrode active material is a material capable of inserting and releasing ions of a metal element belonging to Group 1 or Group 2 of the periodic table. The electrode active material is contained in a solid component. Examples of the electrode active material include a positive electrode active material and a negative electrode active material.

[0059] -Positive Electrode Active Material- The positive electrode active material is not particularly limited, and any known electrode active material used for positive electrodes can be used. The positive electrode active material is preferably a positive electrode active material that can reversibly insert and release lithium ions.

[0060] Specific examples of the positive electrode active material include transition metal oxides and elements that can be composited with lithium (e.g., sulfur). Among the above, the positive electrode active material is preferably a transition metal oxide.

[0061] The transition metal oxide is preferably a transition metal oxide containing at least one transition metal element (hereinafter referred to as "element Ma") selected from the group consisting of Co (cobalt), Ni (nickel), Fe (iron), Mn (manganese), Cu (copper), and V (vanadium).

[0062] When the transition metal oxide contains Li and the element Ma, the molar ratio of Li to Ma (Li / Ma) is preferably 0.3 to 2.2.

[0063] The transition metal oxide may also contain at least one transition metal element (hereinafter referred to as "element Mb") selected from the group consisting of Group 1 elements other than lithium, Group 2 elements, Al (aluminum), Ga (gallium), In (indium), Ge (germanium), Sn (tin), Pb (lead), Sb (antimony), Bi (bismuth), Si (silicon), P (phosphorus), and B (boron). The content of element Mb is preferably 0 mol % to 30 mol % relative to the amount of element Ma.

[0064] Examples of transition metal oxides include transition metal oxides having a layered rock salt structure, transition metal oxides having a spinel structure, lithium-containing transition metal phosphate compounds, lithium-containing transition metal halide phosphate compounds, and lithium-containing transition metal silicate compounds.

[0065] Examples of transition metal oxides having a layered rock salt structure include LiCoO ２ (Lithium cobalt oxide [LCO]), LiNi ２ O ２ (lithium nickel oxide), LiNi ０．８５ Co ０．１０ Al ０．０５ O ２ (nickel cobalt lithium aluminum oxide [NCA]), LiNi １／３ Co １／３ Mn １／３ O ２ (lithium nickel manganese cobalt oxide [NMC]), and LiNi ０．５ Mn ０．５ O ２ (lithium manganese nickel oxide).

[0066] Examples of transition metal oxides having a spinel structure include LiCoMnO ４ , Li ２ FeMn ３ O ８ , Li ２ CuMn ３ O ８ , Li ２ CrMn ３ O ８ , and Li ２ NiMn ３ O ８ Examples include:

[0067] Examples of lithium-containing transition metal phosphate compounds include olivine-type iron phosphate salts (e.g., LiFePO ４ , and Li ３ Fe ２ (P.O. ４ ) ３ ), iron pyrophosphate (e.g., LiFeP ２ O ７ ), cobalt phosphate salts (e.g., LiCoPO ４), monoclinic Nasicon-type vanadium phosphate salts (e.g., Li ３ V ２ (P.O. ４ ) ３ (Lithium vanadium phosphate)).

[0068] Examples of lithium-containing transition metal halophosphate compounds include iron fluorophosphates (e.g., Li ２ FePO ４ F), manganese fluorophosphate salts (e.g., Li ２ MnPO ４ F), and cobalt fluorophosphate salts (e.g., Li ２ CoPO ４ F).

[0069] Examples of lithium-containing transition metal silicate compounds include Li ２ FeSiO ４ , Li ２ MnSiO ４ , and Li ２ CoSiO ４ Examples include:

[0070] The transition metal oxide is preferably a transition metal oxide having a layered rock salt structure, such as LiCoO ２ (Lithium cobalt oxide [LCO]), LiNi ０．８５ Co ０．１０ Al ０．０５ O ２ (nickel cobalt lithium aluminum oxide [NCA]), and LiNi １／３ Co １／３ Mn １／３ O ２ (lithium nickel manganese cobalt oxide [NMC]) is more preferable.

[0071] The positive electrode active material may be a commercially available product or a synthetic product produced by a known method (e.g., a calcination method). For example, the positive electrode active material obtained by the calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent. The positive electrode active material may also have a carbon coating on its surface.

[0072] The shape of the positive electrode active material is not particularly limited, but from the viewpoint of ease of handling, it is preferably in the form of particles.

[0073] The volume average particle size of the positive electrode active material is not particularly limited and can be, for example, 0.1 μm to 50 μm. The volume average particle size of the positive electrode active material is preferably 0.3 μm to 40 μm, and more preferably 0.5 μm to 30 μm. When the volume average particle size of the positive electrode active material is 0.3 μm or more, scattering of the positive electrode active material during handling can be suppressed. When the volume average particle size of the positive electrode active material is 40 μm or less, the thickness of the electrode molded body can be easily adjusted and the occurrence of voids during the molding process can be suppressed.

[0074] The volume average particle size of the positive electrode active material is measured by the following method. A dispersion containing 0.1 mass % or less of the positive electrode active material is prepared by mixing the positive electrode active material with a solvent (e.g., pure water, ethanol, heptane, octane, toluene, or xylene). The dispersion is irradiated with 1 kHz ultrasound for 10 minutes and used as a measurement sample. Using a laser diffraction / scattering particle size distribution measurement device (e.g., LA-960 manufactured by Horiba, Ltd.), data is acquired 50 times at a temperature of 25°C, and the volume average particle size is determined from the volume frequency particle size distribution. A quartz cell is used as the measurement cell. The above measurement is performed using five samples, and the average of the measured values ​​is used as the volume average particle size of the positive electrode active material. For other detailed conditions, refer to "JIS Z 8828:2013" as necessary.

[0075] Examples of methods for adjusting the particle size of the positive electrode active material include methods using a pulverizer, a crusher, or a classifier. Alternatively, known milling methods may be used to adjust the particle size of the positive electrode active material.

[0076] The positive electrode active material may be used alone or in combination of two or more. Even when one type of positive electrode active material is used, positive electrode active materials having different particle sizes may be used in combination.

[0077] The content of the positive electrode active material relative to the total volume of the electrode material film is preferably 30% by volume to 60% by volume, more preferably 35% by volume to 55% by volume, and even more preferably 40% by volume to 50% by volume. In the method for producing an electrode molded body according to the present disclosure, the amount of the positive electrode active material used is determined so that the content in the electrode material film falls within the above-mentioned range.

[0078] -Negative electrode active material- The negative electrode active material is not particularly limited, and any known electrode active material used for negative electrodes can be used. The negative electrode active material is preferably a negative electrode active material that can reversibly insert and release lithium ions.

[0079] Examples of the negative electrode active material include carbonaceous materials, metal oxides (e.g., tin oxide), silicon oxide, metal composite oxides, lithium alone, lithium alloys (e.g., lithium-aluminum alloys), and metals capable of forming alloys with lithium (e.g., Sn, Si, and In). Among these, the negative electrode active material is preferably a carbonaceous material or a lithium composite oxide from the viewpoint of reliability.

[0080] Carbonaceous materials are materials consisting essentially of carbon. Examples of carbonaceous materials include petroleum pitch, carbon black (e.g., acetylene black), graphite (e.g., natural graphite and artificial graphite (e.g., vapor-grown graphite)), hard carbon, and carbonaceous materials obtained by calcining synthetic resins (e.g., polyacrylonitrile (PAN) and furfuryl alcohol resin). Examples of carbonaceous materials include carbon fibers (e.g., polyacrylonitrile-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, dehydrated PVA (polyvinyl alcohol)-based carbon fibers, lignin carbon fibers, glassy carbon fibers, and activated carbon fibers). Examples of graphite include mesophase microspheres, graphite whiskers, and tabular graphite. In this disclosure, "tabular" refers to a shape having two major planes facing in opposite directions.

[0081] The metal composite oxide is preferably a metal composite oxide capable of absorbing and desorbing lithium. From the viewpoint of high current density charge / discharge characteristics, the metal composite oxide capable of absorbing and desorbing lithium preferably contains at least one element selected from the group consisting of titanium and lithium.

[0082] The metal oxide and metal composite oxide are particularly preferably amorphous oxides.

[0083] The metal oxides and metal composite oxides are also preferably chalcogenides, which are reaction products of metal elements and elements of Group 16 of the periodic table.

[0084] Among the group of compounds consisting of amorphous oxides and chalcogenides, amorphous oxides and chalcogenides of metalloid elements are preferred, and oxides and chalcogenides containing at least one element selected from the group consisting of elements of Groups 13 to 15 in the periodic table, Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi are more preferred.

[0085] It is also preferable that the negative electrode active material further contains titanium. From the viewpoint that the volume change during the absorption and desorption of lithium ions is small, and thus rapid charge and discharge characteristics are excellent, and that deterioration of the electrode is suppressed, thereby enabling an improvement in the life of the lithium ion secondary battery, the negative electrode active material containing titanium is preferably Li ４ Ti ５ O １２ (lithium titanate [LTO]) is preferred.

[0086] The negative electrode active material may be a commercially available product or a synthetic product produced by a known method (e.g., a calcination method). For example, the negative electrode active material obtained by the calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

[0087] The negative electrode active material is available, for example, as CGB20 (Nippon Graphite Industries Co., Ltd.).

[0088] The composition of the negative electrode active material is measured using inductively coupled plasma (ICP) emission spectroscopy.

[0089] The shape of the negative electrode active material is not limited, but is preferably particulate from the viewpoints of ease of handling and ease of control of uniformity during mass production.

[0090] The volume average particle size of the negative electrode active material is preferably 0.1 μm to 60 μm, more preferably 0.3 μm to 50 μm, and particularly preferably 0.5 μm to 40 μm. The volume average particle size of the negative electrode active material is measured by a method similar to the method for measuring the volume average particle size of the positive electrode active material.

[0091] The particle size of the negative electrode active material can be adjusted, for example, by using a pulverizer or a classifier.

[0092] The negative electrode active material may be used alone or in combination of two or more. Even when one type of negative electrode active material is used, negative electrode active materials having different particle sizes may be used in combination.

[0093] The content of the negative electrode active material relative to the total volume of the electrode material film is preferably 30% by volume to 60% by volume, more preferably 35% by volume to 57% by volume, and even more preferably 45% by volume to 55% by volume. In the method for producing an electrode molded article according to the present disclosure, the amount of the negative electrode active material used is determined so that the content in the electrode material film falls within the above-mentioned range.

[0094] The surfaces of the positive electrode active material and the negative electrode active material may each be coated with a surface coating agent. Examples of the surface coating agent include metal oxides containing Ti, Nb, Ta, W, Zr, Si, or Li. Examples of the metal oxide include titanate spinel, tantalum-based oxides, niobium-based oxides, and lithium niobate-based compounds.

[0095] [Conductive additive] The electrode material film contains a conductive additive from the viewpoint of improving the electronic conductivity of the electrode active material. There are no limitations on the conductive additive, and known conductive additives can be used. The conductive additive is contained in the solid component.

[0096] Examples of conductive additives include graphite (e.g., natural graphite and artificial graphite), carbon black (e.g., acetylene black, ketjen black, and furnace black), amorphous carbon (e.g., needle coke), carbon fibers (e.g., vapor-grown carbon fibers and carbon nanotubes), other carbonaceous materials (e.g., graphene and fullerene), metal powders (e.g., copper powder and nickel powder), metal fibers (e.g., copper fibers and nickel fibers), and conductive polymers (e.g., polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives).

[0097] The conductive additive may be used alone or in combination of two or more kinds.

[0098] The content of the conductive additive relative to the total volume of the electrode material film is preferably 0.05% by volume to 5% by volume, more preferably 0.1% by volume to 4% by volume, and even more preferably 0.5% by volume to 3% by volume. In the method for producing an electrode molded article according to the present disclosure, the amount of the conductive additive used is determined so that the content in the electrode material film falls within the above-mentioned range.

[0099] [Electrolyte Solution] The electrolyte solution is not particularly limited, and a known electrolyte solution can be used. For example, the electrolyte solution may be an electrolyte solution containing an electrolyte and a solvent. For example, a specific electrolyte solution may be an electrolyte solution containing a lithium salt compound as the electrolyte and a carbonate compound as the solvent.

[0100] An example of the lithium salt compound is lithium hexafluorophosphate. The electrolyte solution may contain one kind of lithium salt compound alone, or may contain two or more kinds of lithium salt compounds.

[0101] Examples of carbonate compounds include linear carbonate compounds such as ethyl methyl carbonate (also referred to as EMC), dimethyl carbonate (also referred to as DMC), and diethyl carbonate (DEC), and cyclic carbonate compounds such as ethylene carbonate (also referred to as EC) and propylene carbonate (also referred to as PC). The electrolyte may contain one type of carbonate compound alone, or may contain two or more types of carbonate compounds, or may use one or more linear carbonate compounds and one or more cyclic carbonate compounds in combination.

[0102] As the electrolyte contained in the electrolytic solution, for example, a known inorganic solid electrolyte can be used.

[0103] An ionic liquid may be used as a component of the electrolytic solution, for example. The ionic liquid may be used as either an electrolyte or a solvent.

[0104] The content of the electrolyte solution relative to the total volume of the electrode material film is preferably 48% by volume or less, and may be 45% by volume or less, or may be 40% by volume or less. The lower limit of the content of the electrolyte solution relative to the total volume of the electrode material film is not limited, and may be 28% by volume or more, or may be 30% by volume or more.

[0105] [Solvent] The electrode material film may contain, as a liquid component, a solvent (hereinafter simply referred to as "solvent") other than the solvent contained as a component of the electrolyte solution. Examples of the solvent include alcohol compound solvents, ether compound solvents, amide compound solvents, amino compound solvents, ketone compound solvents, aromatic compound solvents, aliphatic compound solvents, and nitrile compound solvents.

[0106] The boiling point of the solvent at normal pressure (i.e., 1 atmosphere) is preferably 50° C. or higher, and more preferably 70° C. or higher. The upper limit of the boiling point of the solvent at normal pressure (i.e., 1 atmosphere) is preferably 250° C. or lower, and more preferably 220° C. or lower.

[0107] The solvents may be used alone or in combination of two or more.

[0108] The content of the liquid components (i.e., the electrolyte and the solvent) relative to the total volume of the electrode material film is preferably 48% by volume or less, and may be 45% by volume or less, or 40% by volume or less. The lower limit of the content of the liquid components relative to the total volume of the electrode material film is not limited, and may be 28% by volume or more, or 30% by volume or more.

[0109] Note that the liquid components contained in the electrode material film, i.e., the components in the electrode material film that are liquid at 25° C., are preferably liquid even at −10° C., and are preferably liquid even at −20° C. In other words, the components in the electrode material film that are liquid at 25° C. are preferably components that do not solidify even at −10° C., and are preferably components that do not solidify even at −20° C.

[0110] [Other Components] In addition to the above-mentioned components, the electrode material may contain binders, dispersants, other additives, etc. However, from the viewpoint of improving recyclability and energy density, the electrode material preferably has a low binder content, and more preferably does not contain any binder. Examples of binders include fluorine-containing resins, hydrocarbon-based thermoplastic resins, acrylic resins, and urethane resins. Furthermore, the dispersant may be any known dispersant capable of dispersing the substance to be dispersed. Furthermore, known additives added to electrodes may be used as other additives.

[0111] (Other Steps) The method for producing an electrode molded body according to the present disclosure may include other steps, such as a step of pressurizing the electrode material film.

[0112] [Step of Pressurizing Electrode Material Film] The method for producing an electrode molded body according to the present disclosure may include a step of pressurizing the electrode material film. By including a pressurizing step in the method for producing an electrode molded body according to the present disclosure, the density of the electrode material can be increased and the density and thickness of the solid component can be made uniform within the surface. Note that the electrode material film obtained by the above-mentioned step of forming the electrode material film can be made into a sheet-shaped electrode molded body as is, or by further applying pressure.

[0113] The pressure means used in the step of pressing the electrode material film may be a method using a pair of pressure rollers and a press machine.Furthermore, the pressure means may be a vibrating pressure roller or a vibrating horn.

[0114] When the electrode material film is pressurized, the pressure is preferably 0.01 MPa to 100 MPa, more preferably 0.1 MPa to 50 MPa, and particularly preferably 0.2 MPa to 10 MPa.

[0115] In the step of pressurizing the electrode material film, the electrode material film may be pressurized in stages using a plurality of pressurizing means. By pressurizing the electrode material film in stages using a plurality of pressurizing means, the density and thickness of the electrode material can be made more uniform.

[0116] In the step of pressurizing the electrode material film, it is preferable to move the pressure means and the electrode material film (specifically, the support on which the electrode material film is formed) relative to each other. In the present disclosure, "moving the pressure means and the electrode material film relative to each other" includes moving the pressure means in one direction relative to the electrode material film, moving the electrode material film in one direction relative to the pressure means, and moving both the pressure means and the electrode material film in one direction, but it is preferable to move the electrode material film in one direction relative to the pressure means.

[0117] The means for moving the electrode material film (specifically, the current collector foil on which the electrode material film is formed) is not particularly limited, and any known transport means can be used, including the transport means described above.

[0118] In the step of pressing the electrode material film, from the viewpoint of improving formability, the electrode material film may be heated to, for example, 30° C. to 100° C. before being pressed.

[0119] <Electrode molded body> The electrode molded body obtained by the manufacturing method of the electrode molded body according to the present disclosure can be used as various electrodes. The electrode molded body may be used as an electrode as it is, or may be further processed to form an electrode. The electrode molded body is preferably an electrode molded body for a semi-solid secondary battery.

[0120] From the viewpoint of improving battery performance (e.g., discharge capacity and output characteristics), the electrode molded body preferably has a thickness of 70 μm to 230 μm and a solid component concentration of 50 vol % to 80 vol %, similar to the above-mentioned electrode material film of a single layer structure. The thickness of the electrode molded body is measured in the same manner as the thickness of the electrode material film of a single layer structure. The solid component concentration of the electrode molded body is also calculated in the same manner as the solid component concentration of the electrode material film of a single layer structure.

[0121] The arithmetic mean roughness Ra of the current collector foil in the electrode molded body obtained by the method for producing an electrode molded body according to the present disclosure is preferably 0.1 nm to 1,000 nm, and more preferably 1 nm to 30 nm.

[0122] The current collecting foil may also have a coating layer. Generally, the coating layer of the current collecting foil is provided to roughen the surface. By roughening the surface of the current collecting foil, it is possible to improve adhesion with the electrode material film formed on the current collecting foil.

[0123] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited thereto. Note that each step in each example described below was carried out in a dry room (low dew point room) at 22°C.

[0124] (Method for measuring contact angle of surface) When a droplet of electrolyte in the electrode material used contacted the surface to be measured, the angle formed between the tangent of the droplet and the surface was measured using DMo-902 manufactured by Kyowa Interface Science Co., Ltd.

[0125] (Preparation of Electrolyte (X)) LiPF is added to a mixture of ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC). ６ After mixing the (electrolyte), vinylene carbonate (VC) was further mixed to obtain an electrolytic solution (X).

[0126] (Preparation of Electrode Material 1) 2 parts by mass of a conductive additive (Ketjen black), 174 parts by mass of a positive electrode active material (lithium iron phosphate), and 32 parts by mass of the electrolyte solution (X) were stirred and mixed in a mixer (Awatori Rentaro ARE-310, manufactured by Thinky Corporation) at 700 rpm (revolutions per minute) for 1 minute to obtain electrode material 1.

[0127] (Preparation of current collector foil) Current collector foil: Positive electrode current collector (aluminum foil, average thickness 20 μm, Ra 0.5 μm) Note that Ra of the current collector refers to the arithmetic mean roughness Ra of the surface on which the electrode material film is formed. The contact angle of the current collector foil was 19 degrees.

[0128] (Surface Treatment of Second Molded Member) Surface treatment of surface B of the second molded member was carried out by the following method. Finishing was carried out by buffing with a 1000-number buff. The surface-treated member was evaluated by surface roughness Ra using a VK-X3000 manufactured by Keyence Corporation, a non-contact method using a general optical interference method.

[0129] Example 1: Electrode material 1 was applied to a current collector foil being conveyed using a twin-shaft screw feeder manufactured by Seiwa Giken Co., Ltd., to form a film approximately 300 μm thick. Subsequently, the angles θ1, θ2, and θ3 and the distances between the first and second shaping members 12A and 12B were set to the values ​​listed in Table 1, and the film 14 formed on the current collector foil 18 was pressed. Specifically, the shaping member was positioned so that the distance between the surface of the current collector foil 18 and the tip of the shaping member was 200 μm. Then, as shown in FIG. 5 , the current collector foil 18 was conveyed in the direction of arrow CD, and the film 14 formed on the current collector foil 18 was brought into contact with the shaping member, forming an electrode material film 22 measuring 200 mm x 150 mm x 200 μm (thickness) on the current collector foil 18. The solid component concentration of the resulting electrode material film was 56% by volume. The first and second shaping members 12A and 12B were made of stainless steel. Furthermore, the first shaping member 12A is ultrasonically vibrated by an ultrasonic vibrator (not shown), while the second shaping member 12B is not vibrated.

[0130] <Examples 2 to 8 and 10 to 13, and Comparative Examples 1 and 2> An electrode material film was formed in the same manner as in Example 1, except that the angles θ1, θ2, and θ3 and the distances from the first molding member 12A and the second molding member 12B were set to the values ​​shown in Table 1.

[0131] Example 9 An electrode material film was formed in the same manner as in Example 1, except that the forming portion 12 shown in FIG. 2 was used and the angles θ1, θ2, and θ3 shown in Table 1 were set.

[0132] Example 14 An electrode material film was formed in the same manner as in Example 1, except that the surface of face B of the second molded member 12B was surface treated by the following method: Surface treatment: Finished by buffing with a buff of 80 grit.

[0133] (Evaluation of Continuity of Electrode Material Film) Ten sheets of the obtained electrode material film (sample) were prepared, and each electrode material film was visually inspected for the presence of continuous films and defects. A continuous film is defined as a film in which the electrode material is formed without defects for 50 mm or more in the conveyance direction of the current collector foil, and a film having interruptions along the way is considered an intermittent film. Defects were visually inspected to see if the current collector foil was exposed at the attempted continuous film location. The presence of even one defect was considered a "defect." "Continuity" and "defect" were evaluated using the following scores, with a score of 3 or higher being considered a pass. 0: No film was formed. 1: All films were intermittent. 2: Only one sample was continuous. 3: All samples were continuous, but defects occurred in all samples. 4: All samples were continuous, but defects occurred in some samples. 5: All samples were continuous, and all samples were defect-free.

[0134] (Evaluation of thickness uniformity of electrode material film) The thickness of the obtained electrode material film was measured at nine points at the portion formed into a continuous film. The measurement method may be either non-contact or contact, but in this case, a thickness gauge (high precision type) manufactured by Mitutoyo Corporation, which is a general contact type film thickness meter, was used. ｍａｘ , minimum t ｍｉｎ , the average of the nine points is t ａｖｅ Then, Δ is defined as follows: Δ=(t ｍａｘ -t ｍｉｎ ) ÷ t ａｖｅ ÷2×100(%) The uniformity was evaluated using the above Δ, and the evaluation was carried out using the following scores. A score of 3 or more was considered good: 1: Δ≧50% 2: 25%≦Δ<50% 3: 10%≦Δ<25% 4: 5%≦Δ<10% 5: Δ<5%

[0135]

[0136] In Table 1, member 1 represents the first molding member, member 2 represents the second molding member, and the surface treatment method and Ra in Table 1 represent the surface treatment method and surface roughness Ra of surface B.

[0137] As shown in Table 1, the methods for manufacturing electrode molded bodies of Examples 1 to 14, which are methods for manufacturing electrode molded bodies according to the present disclosure, suppressed the electrode material from rising up into the molded part, and the resulting electrode material film had excellent continuity, compared to the methods for manufacturing electrode molded bodies of Comparative Examples 1 and 2.

[0138] The disclosure of Japanese Patent Application No. 2024-050266, filed on March 26, 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0139] 10: Film forming device, 12: Forming section, 12A: First forming member, 12B: Second forming member, 14: Electrode material, 16: Conveying means, 18: Current collecting foil, 20: Low viscosity region, 22: Electrode material film, A: Surface A, B: Surface B, C: Surface C, CD: Conveying direction

Claims

1. A method for manufacturing an electrode molded body, comprising: a step of supplying an electrode material containing an electrode active material, a conductive additive, and an electrolyte onto a current collector foil being conveyed; and a step of using a forming unit to level the electrode material supplied onto the current collector foil and form an electrode material film, wherein the forming unit faces the current collector foil, the distance from the current collector foil gradually decreases toward the downstream side in the conveyance direction of the current collector foil, and the forming unit has a surface A closest to the current collector foil, and a surface B of the forming unit located more upstream of surface A in the conveyance direction of the current collector foil, and an angle θ1 between surface A of the forming unit and the conveyance direction of the current collector foil, and an angle θ2 between surface B and a horizontal plane satisfy the following formula 1. 0 degrees < θ1 < θ2 ≦ 90 degrees Formula 1 2. The method for producing a molded body for an electrode according to claim 1, wherein an angle θ3 formed between a surface C of the molded portion located downstream of the surface A in the conveyance direction of the current collector foil and a horizontal plane satisfies the following formula 3: 30 degrees≦θ3<180 degrees−θ1 Formula 3 3. A method for producing an electrode molded body according to claim 2, wherein the molded portion is constituted by a first molded member having the surface A and the surface C, and a second molded member having the surface B.

4. A method for manufacturing an electrode molded body as described in claim 3, wherein the first molding member and the second molding member are spaced apart from each other by 0.01 mm to 10 mm, and in the process of molding the electrode material film, the first molding member vibrates and the second molding member is in a non-vibrating state.

5. The method for producing an electrode molded body according to claim 1 or 2, wherein the contact angle of said surface B with respect to the electrolyte is smaller than the contact angle of said current collecting foil with respect to the electrolyte.

6. The method for producing a molded body for an electrode according to claim 1 or 2, wherein θ1 satisfies the following formula 1-1: 5 degrees≦θ1≦30 degrees Formula 1-1 7. The method for producing a molded article for an electrode according to claim 1 or 2, wherein θ2 satisfies the following formula 2-1: θ1+5 degrees≦θ2≦90 degrees Formula 2-1 8. The method for producing a molded article for an electrode according to claim 2, wherein θ3 satisfies the following formula 3-1: 90 degrees < θ3 < 180 degrees - θ1 Formula 3-1

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