Method for manufacturing molded body for sheet electrode

Abstract

The present invention provides a method for manufacturing a molded body for a sheet electrode, the method comprising: a step (A) in which a plurality of lumps of an electrode material containing an electrode active material and an electrolyte solution and having a solid content concentration of 20-90 vol% are dispersed on a support body; and a step B for forming an electrode material film on the support body by combining the plurality of lumps dispersed on the support body by means of the molding member.

Description

Technical Field

[0001] The present invention relates to a method for producing a formed body for a sheet-like electrode. Background Art

[0002] In recent years, the development of semi-solid-state batteries has been explored.

[0003] The electrode used for the semi-solid battery is produced using, for example, an electrode material containing at least a powdered electrode active material and an electrolyte.

[0004] For example, Japanese Patent Application Laid-Open No. 2014-186969 discloses an electrode manufacturing apparatus including a mechanism for supplying a powder containing granulated particles including an electrode active material, a binder, and a conductive material onto a support using a brush-like member.

[0005] A method for manufacturing an electrode material for a lithium-ion battery is disclosed in Japanese Patent Gazette No. 2021-027043, which is a method for manufacturing an electrode material for a lithium-ion battery in which an electrode composition layer configuration portion having an electrode composition layer containing an electrode composition containing an electrode active substance is intermittently configured on the surface of a continuous sheet-like substrate, and comprises: a supply process, continuously supplying the above-mentioned electrode composition to the above-mentioned substrate; a pressurizing process, pressurizing the above-mentioned electrode composition supplied to the above-mentioned substrate by the above-mentioned supply process to obtain the above-mentioned electrode composition layer; and a removal process, removing a part of the above-mentioned electrode composition supplied to the above-mentioned substrate by the above-mentioned supply process, and forming an electrode composition layer configuration portion on the above-mentioned substrate. Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] In the manufacture of an electrode for a semi-solid battery, for example, the following steps are included: using an electrode material containing at least an electrode active material (an example of a solid component) as a powder and an electrolyte (an example of a liquid component), the electrode material is formed into a sheet (also referred to as a layer or a film) on a support. In this step, (1) a method of extruding the electrode material onto the support with the same thickness as the sheet-shaped electrode molded body to be manufactured, or (2) a method of extruding the electrode material onto the support with a thickness thicker than the sheet-shaped electrode molded body to be manufactured, and adjusting the thickness of the extruded electrode material on the support.

[0008] The electrode material used in the production of semi-solid batteries contains a larger amount of electrode active material in the form of powder than the electrolyte and exhibits clay-like properties.

[0009] When such an electrode material is applied to the method (1) above, the electrode material needs to be extruded from a long and narrow rectangular discharge port under a strong pressure (load), and thus a large load is applied to a device for discharging the electrode material.

[0010] On the other hand, when an electrode material having a clay-like property is applied to the method (2) above, unlike the method (1) above, it is not necessary to apply a strong pressure to extrude the electrode material from the elongated rectangular outlet. However, in the method (2), the thickness of the extruded electrode material is adjusted by removing excess material with a forming member such as a scraper or by pressing with a punch and further discharging the excess material outside the support body, but since the electrode material has a clay-like property, a large load is required when deforming the electrode material by a forming member or a punch.

[0011] That is, as described above, the method of (1) and the method of (2) include a process of applying a large load to the electrode material. In order to apply a large load to the electrode material, the device or component for holding the electrode material must be large-scale and strong. In addition, by applying a large load, the solid component and the liquid component of the electrode material are separated, and sometimes it is difficult to form an electrode material film of a target thickness.

[0012] Therefore, the present invention has been completed in view of the above circumstances.

[0013] An object of one embodiment of the present invention is to provide a method for producing a sheet-shaped electrode molded body that can reduce the load applied to an electrode material and can produce a sheet-shaped electrode molded body having a target thickness.

[0014] Means for solving technical problems

[0015] The present invention includes the following aspects.

[0016] <1> A method for producing a sheet-shaped electrode molded body, comprising:

[0017] Step A, dispersing a plurality of blocks of an electrode material including an electrode active material and an electrolyte and having a solid content concentration of 20 volume % to 90 volume % on a support; and

[0018] In step B, a plurality of blocks dispersedly arranged on a support are combined by a molding component to form an electrode material film on the support.

[0019] <2> The method for producing a sheet-shaped electrode molded body according to <1>, wherein:

[0020] By moving the molding member relatively along the support surface while maintaining a constant distance from the support surface, a plurality of blocks dispersed on the support are combined to form an electrode material film on the support.

[0021] <3> The method for producing a sheet-shaped electrode molded body according to <2>, wherein:

[0022] When the average height of the plurality of blocks dispersed on the support is H and the distance between the molded component and the support surface is C, the ratio of the height H to the distance C (H / C) satisfies 1<H / C≤100.

[0023] <4> The method for producing a sheet-shaped electrode molded body according to any one of <1> to <3>, wherein:

[0024] The pressure applied from the molded part to the electrode material (lump) is 10 kPa to 500 kPa.

[0025] <5> The method for producing a sheet-shaped electrode molded body according to any one of <1> to <4>, wherein:

[0026] Among the plurality of blocks dispersedly arranged on the support, the distance between the area centers of gravity of adjacent blocks is 0.1 mm to 50 mm.

[0027] <6> The method for producing a sheet-shaped electrode molded body according to any one of <1> to <5>, wherein:

[0028] The area occupied by the plurality of masses dispersedly arranged on the support is 10% to 90% of the area where the electrode material film is formed on the support.

[0029] <7> The method for producing a sheet-shaped electrode molded body according to any one of <1> to <6>, wherein:

[0030] Step A is performed by scattering and supplying a plurality of lumps of an electrode material containing an electrode active material and an electrolyte solution and having a solid content concentration of 20 volume % to 90 volume % onto a support.

[0031] <8> The method for producing a sheet-shaped electrode molded body according to any one of <1> to <7>, wherein:

[0032] The step A and the step B are performed using a continuously transported support, and in the step B, an electrode material film is formed as a continuous film along the transport direction of the support.

[0033] <9> The method for producing a sheet-shaped electrode molded body according to <7> or <8>, wherein:

[0034] When the theoretical amount of electrode material that can form an electrode material film with the same thickness as the distance between the molded part and the surface of the support body and without a gap is set to X, and the supply amount of the block of electrode material on the support body is set to Y, the ratio of the supply amount Y to the amount X (Y / X) satisfies 1≤Y / X≤5 on a volume basis.

[0035] Effects of the Invention

[0036] According to one embodiment of the present invention, it is possible to provide a method for producing a sheet-shaped molded body for a sheet-shaped electrode, which can reduce the load applied to an electrode material and produce a sheet-shaped molded body for a sheet-shaped electrode having a target thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram showing an example of the shape of a block.

[0038] Figure 2 This is a schematic cross-sectional view of a state where a plurality of blocks are dispersedly arranged on a support, when the support is cut along the thickness direction.

[0039] Figure 3 This is a schematic diagram of the upper surface when a plurality of blocks are dispersedly arranged on a support body as viewed from the upper surface.

[0040] Figure 4 This is a schematic cross-sectional view for explaining a method of combining a plurality of blocks dispersedly arranged on a support body by a molding component.

[0041] Figure 5 This is a schematic top view for explaining a method of combining a plurality of blocks dispersedly arranged on a support body by a molding component. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments and can be implemented with appropriate changes within the scope of the purpose of the present invention. Constituent elements represented by the same symbols in the drawings refer to the same constituent elements. The description of the constituent elements and symbols repeated in the drawings may sometimes be omitted. The ratio of the dimensions in the drawings does not necessarily represent the ratio of the actual dimensions.

[0043] In the present invention, the numerical range represented by "to" refers to a range including the numerical values ​​recorded before and after "to" as the lower limit and the upper limit. In the numerical range recorded in stages in the present invention, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical range recorded in the present invention, the upper limit or lower limit recorded in a certain numerical range can be replaced by the value shown in the embodiment.

[0044] In the present invention, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0045] In the present invention, "(meth)acrylic acid" means both or either one of acrylic acid and methacrylic acid.

[0046] In the present invention, when a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition refers to the total amount of the plurality of substances present in the composition unless otherwise specified.

[0047] In the present invention, a combination of two or more preferred aspects or configurations is a more preferred aspect or configuration.

[0048] In the present invention, the "solid content" refers to a component that is solid at 25°C and 1 atmosphere, and the "liquid content" refers to a component that is liquid at 25°C and 1 atmosphere.

[0049] In the present invention, the formation area of ​​the electrode material film on the support refers to the area of ​​the total surface area of ​​the support where the electrode material film is formed by merging the blocks of the electrode material, and is equivalent to the area covered by the electrode material film on the support. In addition, if the support is a collector or a laminate of a collector and a resin film, the area of ​​the collector becomes the formation area of ​​the electrode material film.

[0050] Furthermore, in the present invention, the “width direction” in the support refers to a direction perpendicular to the longitudinal direction, and in the case of a long support, refers to a direction perpendicular to the longitudinal direction.

[0051] In addition, the "width direction" of the film forming member (e.g., the scraper) refers to the direction orthogonal to the direction in which the film forming member moves relative to the surface of the support (i.e., the direction in which the electrode material film is formed on the support). That is, the "width direction" of the scraper is also equivalent to the "width direction" of the electrode material film.

[0052] <Method for producing a molded body for sheet-shaped electrode>

[0053] The method for manufacturing a formed body for a sheet electrode involved in the present invention includes: step A, dispersing multiple blocks of electrode material containing an electrode active substance and an electrolyte and having a solid content concentration of 20 volume % to 90 volume % on a support; and step B, merging the multiple blocks dispersed on the support by a molding component to form an electrode material film on the support.

[0054] Hereinafter, “an electrode material comprising an electrode active material and an electrolyte solution and having a solid content concentration of 20% to 90% by volume” is also referred to as a “specific electrode material”, and a “sheet-shaped electrode molded body” is also simply referred to as an “electrode molded body”.

[0055] An electrode material (i.e., a specific electrode material) comprising an electrode active material and an electrolyte and having a solid content concentration of 20% to 90% by volume has a clay-like property. The present inventors have studied a method for obtaining a sheet-shaped electrode molded body of a target thickness without applying a large load to the electrode material using the electrode material having the clay-like property.

[0056] As a result of the study, it was found that a plurality of blocks of electrode materials having clay-like properties were first dispersed on a support, and then the dispersed blocks were merged by a forming component to form an electrode material film. According to this method, it is believed that the contact area between the forming component and the block is small, and the load applied to the electrode material from the forming component is small. In addition, when the plurality of blocks are merged, an electrode material film of a target thickness can be formed by adjusting the forming component.

[0057] As a result, in the method for producing a molded body for an electrode according to the present invention, a sheet-shaped molded body for an electrode having a target thickness can be produced while reducing the load applied to the electrode material.

[0058] In the manufacturing method of the electrode molded body involved in the present invention, even if a large load is not applied to the electrode material, a sheet-shaped electrode molded body of a target thickness can be formed. As a result, the time required to apply a large load to the electrode material can be shortened. In addition, it is not necessary to enlarge and strengthen the device or component that holds the electrode material in order to apply a large load to the electrode material.

[0059] In Japanese Patent Application Laid-Open No. 2014-186969, the powder supplied onto the support has a structure containing a small amount of electrolyte and does not belong to a specific electrode material.

[0060] Furthermore, Japanese Patent Application Laid-Open No. 2021-027043 does not describe the following: a plurality of blocks dispersedly arranged on a support are combined by a molding component to form an electrode material film on the support.

[0061] [Process A]

[0062] In step A, a plurality of blocks of an electrode material (ie, a specific electrode material) containing an electrode active material and an electrolyte solution and having a solid content concentration of 20 volume % to 90 volume % are dispersed and arranged on a support.

[0063] (lump)

[0064] In the present invention, "agglomerates of electrode materials" refer to granules (also referred to as particles) with a diameter of 0.1 mm to 20 mm or their secondary particles (i.e., aggregates). Here, granules with a diameter of 0.1 mm to 20 mm are particles containing a mixture of at least an electrode active material and an electrolyte.

[0065] use Figure 1 , the block is explained. Here, Figure 1 This is a schematic diagram showing an example of the shape of a block.

[0066] like Figure 1 As shown, the mass 20 is, for example, an aggregate formed by agglomerating three granular materials 22. The number of granular materials 22 included in the mass 20 is not particularly limited.

[0067] Here, in the measurement of the diameter of the granular material, a known method of obtaining a circle-equivalent diameter is used. That is, the diameter of the granular material refers to the circle-equivalent diameter of the granular material.

[0068] Furthermore, the shape of the granular material is not particularly limited, and may be spherical, elliptical, cylindrical, flat, or irregular.

[0069] In this process, if Figure 2 and Figure 3 As shown, a plurality of blocks 20 are dispersedly arranged on the support 10. Here, Figure 2 This is a schematic cross-sectional view of a state where a plurality of blocks are dispersedly arranged on a support body and cut along the thickness direction of the support body. Figure 3 This is a schematic diagram of the upper surface when a plurality of blocks are dispersedly arranged on a support body as viewed from the upper surface.

[0070] The diameter of the masses dispersed and arranged on the support is, for example, preferably 0.1 mm to 20 mm, more preferably 0.5 mm to 10 mm, and even more preferably 1 mm to 5 mm.

[0071] In measuring the diameter of the lump, a known method of obtaining a circle-equivalent diameter is used. That is, the diameter of the lump refers to the circle-equivalent diameter of the lump.

[0072] The average height of the masses dispersed on the support is, for example, preferably 0.1 mm to 10 mm, more preferably 0.5 mm to 10 mm, and even more preferably 1 mm to 5 mm.

[0073] The height of the block is equivalent to Figure 2 The "H" in "H". The height of the block is obtained by measuring with a laser displacement meter using the support as a reference. In addition, regarding the measurement, when all blocks existing in the formation area of ​​the electrode material film on the support are set to 100% by number, blocks corresponding to 50% by number (decimal parts are discarded) randomly selected therefrom are measured, and the arithmetic mean of the measured values ​​obtained is taken as the "average height of the blocks".

[0074] In the plurality of blocks dispersedly arranged on the support, the distance between the area centers of gravity of adjacent blocks is preferably 0.1 mm to 50 mm, more preferably 1 mm to 20 mm, and even more preferably 5 mm to 10 mm.

[0075] The distance between the area centroids of adjacent blocks is equivalent to Figure 3 The distance between the area centroids of adjacent lumps is obtained by obtaining an image of a support in which the lumps are dispersed as viewed from the upper surface, identifying one lump (reference lump) in the image, selecting the adjacent lump closest to the granular material (near lump), and measuring the area centroids of these adjacent lumps ( Figure 3 In addition, as the above-mentioned reference block, when all blocks existing in the formation area of ​​the electrode material film on the support are set to 100% by number, blocks corresponding to 25% by number (rounded down to the decimal point) of them are selected. When selecting the reference block, the reference block selected once and its close blocks are excluded. The arithmetic mean of the obtained measured values ​​is set as "the distance between the area centroids of adjacent blocks".

[0076] Furthermore, in the case of a method in which an electrode material film is continuously formed on a continuously conveyed support along the conveying direction of the support, as an image of the support when observing the support from the upper surface, it is sufficient to use a two-dimensional image obtained by connecting images of one line obtained by a line sensor camera (line sensor camera) set along the width direction of the support.

[0077] Relative to the formation area of ​​the electrode material film on the support, the area occupied by multiple blocks dispersed on the support (hereinafter also referred to as the area ratio of blocks) is preferably 10% to 90%, more preferably 10% to 40%, and further preferably 10% to 20%.

[0078] Here, the formation area of ​​the electrode material film on the support refers to the area in the total surface area of ​​the support where the electrode material film is formed by merging the blocks of the electrode material, and is equivalent to the area covered by the electrode material film on the support. In addition, if the support is a collector or a laminate of a collector and a resin film, the area of ​​the collector becomes the formation area of ​​the electrode material film.

[0079] The area ratio of the lumps was calculated as follows.

[0080] That is, first, an image of a support in which the lumps are dispersed is obtained when viewed from the upper surface, the image is binarized, and the area occupied by the lumps on the support is calculated. Then, the area occupied by the lumps calculated is introduced into the formula: area occupied by the lumps / formation area of ​​the electrode material film on the support × 100 to obtain the area occupied by the lumps.

[0081] Furthermore, in the case of a method in which an electrode material film is continuously formed on a continuously conveyed support along the conveying direction of the support, as an image when the support is observed from the upper surface, it is sufficient to use a two-dimensional image obtained by a line sensor camera, similarly to when calculating the distance between the area centroids of adjacent blocks.

[0082] In step A, there is no particular limitation on the method of dispersing multiple blocks of a specific electrode material on a support, but from the perspective of easily adjusting the size of the blocks, easily adjusting the dispersion state of the blocks, and stabilizing the supply amount, it is preferably carried out by the following method.

[0083] That is, step A is preferably performed by scattering and supplying a plurality of lumps of the specific electrode material onto the support. That is, by scattering and supplying a plurality of lumps of the specific electrode material prepared in advance onto the support, the plurality of lumps of the specific electrode material can be dispersedly arranged on the support.

[0084] The plurality of agglomerates of the specific electrode material used in the above-mentioned scattered supply can be produced by a known granulation mechanism capable of granulating the specific electrode material.

[0085] Examples of the granulation mechanism include an extrusion granulation method, a pulverization granulation method, a compression granulation method, a wet (agglomeration) granulation method, and a granulation method using a slicer.

[0086] The agglomerates obtained by the granulation mechanism are scattered and supplied onto the support by a known conveying mechanism and supply mechanism.

[0087] Furthermore, the scattered supply can be performed by relatively moving the supply mechanism along the surface of the support.

[0088] (Specific electrode materials)

[0089] The details of the specific electrode material used in step A will be described later.

[0090] [Process B]

[0091] In step B, a plurality of blocks dispersedly disposed on a support are combined by a molding member to form an electrode material film on the support.

[0092] In particular, in step B, it is preferred that the electrode material film is formed on the support by relatively moving the molding member along the support surface while maintaining a constant distance from the support surface to merge a plurality of blocks dispersed on the support.

[0093] refer to Figure 4 and Figure 5 , the process B is described. Here, Figure 4 It is a schematic cross-sectional view for explaining a method of combining a plurality of blocks dispersedly arranged on a support body by a molding component. Figure 5 This is a schematic top view for explaining a method of combining a plurality of blocks dispersedly arranged on a support body by a molding component.

[0094] like Figure 4 As shown in the figure, the scraper (an example of a molding component) 30 is provided in a manner that maintains a constant distance from the surface of the support body 10. Hereinafter, the distance between the front end of the scraper 30 (specifically, the corner of the scraper 30 closest to the surface of the support body 10) and the surface of the support body 10 is also appropriately referred to as "distance C". In other words, a gap having a distance C is formed between the surface of the support body 10 and the front end of the scraper 30.

[0095] like Figure 4 As shown in FIG. 1 , if the support 10 moves in the direction of arrow X, the blocks 20 dispersedly arranged on the support 10 contact the scraper 30. The blocks 20 contacting the scraper 30 are respectively moved along the width direction of the support 10 (equivalent to Figure 4 As a result, the multiple blocks 20 pushed and pulled on the support 10 are merged with each other, as shown in the depth direction of the support 10 and the direction opposite to the arrow X. Figure 4 and Figure 5 As shown, an electrode material film 24 is formed. Figure 4 As shown, the distance C between the scraper 30 and the surface of the support 10 is smaller than the height of the block 20 , so that the block 20 is effectively in contact with the scraper 30 , and the blocks 20 pushed and pulled on the support 10 are merged with each other.

[0096] Then, as the masses 20 dispersedly disposed on the support 10 pass through the gap having the distance C, a load is applied to the masses 20 and the thickness is restricted, so that the electrode material film 24 having the same thickness as the distance C is formed.

[0097] like Figure 5 As shown, the electrode material film 24 formed as described above is not limited to the mode having the same width as the width of the scraper 30. By adjusting the arrangement of the block 20 on the support 10, the supply amount, etc., the width of the electrode material film 24 can be made smaller than the width of the scraper 30, and can also be set to be the same as the width of the scraper 30.

[0098] The setting position of the scraper can be determined based on the above-mentioned distance C set according to the film thickness of the electrode material film to be formed. In addition, "in a manner of maintaining a constant distance from the support surface", it is sufficient that the distance between the support surface and the front end of the central part of the scraper in the width direction is substantially constant when the scraper moves relatively along the support surface. In "in a manner of maintaining a constant distance from the support surface", for example, the amplitude of the scraper caused by the vibration of the scraper is allowed. In addition, in "in a manner of maintaining a constant distance from the support surface", the position change of the support surface during the transportation of the support (the suspension of the support, the position change caused by the wrinkles on the support), the surface roughness on the support surface, etc. are also allowed. According to these contents, in "in a manner of maintaining a constant distance from the support surface", if the variation value of the distance between the support surface and the front end of the scraper when the scraper moves relatively along the support surface is within 3% or less than 20μm relative to the distance between the support surface and the front end of the scraper in the stopped state (that is, the height of the gap), the variation is allowed.

[0099] Furthermore, the distance between the support surface and the front end of the scraper (ie, the height of the gap) may have some distribution in the width direction thereof, but such distribution is permitted as long as it is within 3% or within 20 μm.

[0100] In addition, the scraper is preferably connected to a pressure mechanism (not shown). Furthermore, the pressure mechanism is preferably used to pressurize the scraper toward the support body in a manner that maintains a constant distance C even when the scraper is in contact with the block and moves relatively along the surface of the support. Furthermore, the scraper is preferably pressed in a manner that opposes the repulsive force from the block in contact (i.e., the force of the block pushing the scraper away) to maintain a constant distance C. By setting it in this way, an electrode material film with less thickness deviation is formed.

[0101] Furthermore, the electrode material film is formed by the block passing through the gap having a distance C, but at this time, it is preferred that at least the contact portion of the scraper with the block vibrates. The contact portion of the scraper with the block vibrates, and the vibration propagates to the block, applying a shear force to the block. The viscosity of the block to which the shear force is applied is reduced or the fluidity is improved, so it is presumed that the merging of the blocks is promoted. Furthermore, in this manner, the surface of the electrode material film formed becomes uniform, forming an electrode material film with less thickness deviation.

[0102] The vibrator for vibrating the scraper is not particularly limited as long as it can vibrate at least the contact portion of the scraper with the block, and examples thereof include pneumatic vibrators, motor vibrators, piezoelectric vibrators, and ultrasonic vibrators.

[0103] exist Figure 4 and Figure 5 In FIG. 1 , the support body 10 is shown to be transported and moved in the direction of arrow X relative to the fixed scraper 30 , but the present invention is not limited to this embodiment.

[0104] In the method for manufacturing an electrode molded body involved in the present invention, as long as the surface of the support body and the scraper move relative to each other, in addition to the above-mentioned method, it can also be a method in which the scraper is moved in one direction relative to the fixed support body, or it can be a method in which both the support body and the scraper are moved in one direction respectively.

[0105] However, in order to continuously form the electrode material film, that is, to form the electrode material film as a continuous film, it is preferable to use a long support and to move the long support by conveyance relative to a fixed scraper.

[0106] And, in Figure 4 and Figure 5 In FIG. 1 , a method of using a scraper as a molding member is shown, but the present invention is not limited to this method.

[0107] As the molding member, a roller may be mentioned in addition to the scraper. When the molding member is a roller, the roller may be provided at a constant distance from the support surface, similarly to the scraper.

[0108] The roller can rotate while contacting the plurality of lumps dispersedly arranged on the support, and stretch the lumps on the support. As a result, the plurality of lumps stretched on the support are combined with each other to form an electrode material film.

[0109] (Ratio (H / C))

[0110] In process B, from the viewpoint of facilitating the merging of blocks, when the average height of a plurality of blocks dispersed on the support is set to H and the distance between the molding component and the surface of the support is set to C (equivalent to the distance C already described), the ratio of the height H to the distance C (H / C) preferably satisfies 1<H / C≤100, more preferably satisfies 1<H / C≤50, and even more preferably satisfies 1<H / C≤10.

[0111] Here, the distance C is obtained by measuring with a laser displacement meter using the height at which the scraper and the support are in contact as a reference. Alternatively, the distance C can be measured with a mechanical measuring instrument.

[0112] (Pressure applied to electrode material)

[0113] In step B, when the block is in contact with the molding component, pressure is applied from the molding component to the block, i.e., the specific electrode material. At this time, the pressure applied to the block, i.e., the specific electrode material in contact with the molding component is preferably 10 kPa to 500 kPa, more preferably 10 kPa to 100 kPa, and further preferably 10 kPa to 20 kPa.

[0114] Here, the pressure applied to the electrode material is obtained by the following method.

[0115] That is, by using an actuator (cylinder, motor-driven linear actuator, piezoelectric, etc.) to press the molded component with a certain force against a block (i.e., electrode material) dispersed on a support body, and then moving the molded component relatively along the surface of the support body, the force based on the actuator is divided by the pressure area of ​​the electrode material to form an electrode material film of target thickness.

[0116] Methods for changing the pressure applied to a block, i.e., a specific electrode material, in contact with a molded component include adjusting the distance between the support surface and the molded component, the pressure with which the molded component is pressed toward the support surface, the weight of the molded component, and one or more other methods.

[0117] (Preferred method)

[0118] The method for producing an electrode molded body according to the present invention preferably uses a continuously conveyed support to perform steps A and B, and forms an electrode material film as a continuous film along the conveying direction of the support in step B. In addition, step A is preferably performed by scattering and supplying a plurality of lumps of a specific electrode material onto the continuously conveyed support.

[0119] In this preferred embodiment, the electrode material film is continuously formed on the support that is continuously transported along the transport direction of the support.

[0120] By adopting this method, an electrode material film can be formed with good productivity.

[0121] Furthermore, in this preferred embodiment, when the theoretical amount of electrode material that can form an electrode material film with a thickness equal to the distance between the molded part and the surface of the support body and without a gap is set to X, and the supply amount of the block of electrode material on the support body is set to Y, the ratio of the supply amount Y to the amount X (Y / X) preferably satisfies 1≤Y / X≤5 on a volume basis.

[0122] In addition, in a method of continuously forming an electrode material film along the conveyance direction of the support, the value of the ratio (Y / X) can be appropriately adjusted within the above range.

[0123] Here, the value of the ratio (Y / X) can be adjusted by changing the supply amount Y. The supply amount Y may be the same or different during the process A.

[0124] Here, when the thickness of the electrode material film to be formed is T [mm], the width of the electrode material film is W [mm], and the film forming speed (i.e., the conveying speed of the support body) is V [mm / sec], the theoretical amount of electrode material X is calculated according to X [mm 3 / second] = T × W × V to find out.

[0125] And, the supply amount Y[mm 3 / sec] is calculated based on the flow rate of a supply mechanism (e.g., a pump, a feeder, etc.) that supplies the electrode material.

[0126] 〔Other processes〕

[0127] The method for producing the electrode molded body according to the present invention may include other steps.

[0128] Examples of other steps include a step of pressing the electrode material film and a step of transferring the electrode material film formed on the release paper to the current collector when the support is release paper.

[0129] (Step of Pressurizing Electrode Material Film)

[0130] The method for producing a molded body for an electrode according to the present invention may include a step of pressurizing the electrode material film obtained in step B.

[0131] Since the method for producing an electrode molded body according to the present invention includes a pressurizing step, the density of the electrode material can be increased and the density and thickness can be made uniform within a plane.

[0132] Examples of the pressurizing mechanism used in this step include a pressurizing roller pair and a punch.

[0133] 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.

[0134] In this step, multiple pressurizing mechanisms (eg, a pair of pressurizing rollers) may be used to pressurize the electrode material film in stages. By using multiple pressurizing mechanisms to pressurize the electrode material film in stages, the density and thickness of the electrode material can be made more uniform.

[0135] For example, by using a plurality of pressurizing roller pairs adjusted so that the gap between the rollers is gradually narrowed, the electrode material film can be pressurized in a step-by-step manner.

[0136] In this step, it is preferred that the pressurizing mechanism and the electrode material film (specifically, the support on which the electrode material film is formed) are relatively moved.

[0137] In the present invention, "moving the pressurizing mechanism and the electrode material film relative to each other" includes moving the pressurizing mechanism in one direction relative to the electrode material film, moving the electrode material film in one direction relative to the pressurizing mechanism, and moving the pressurizing mechanism and the electrode material film in one direction respectively, but preferably moving the electrode material film in one direction relative to the pressurizing mechanism.

[0138] The mechanism for moving the electrode material film (specifically, the support body on which the electrode material film is formed) is not limited, and a known conveying mechanism can be used, for example, a belt conveyor, a linear slide guide, and a cross roller conveyor.

[0139] In this step, from the viewpoint of improving moldability, the electrode material film heated at, for example, 30° C. to 100° C. may be pressed.

[0140] Hereinafter, the support, the molding component, and the electrode material used in the method for producing the molded body for an electrode according to the present invention will be described in detail.

[0141] [Support]

[0142] The support used in this process is not particularly limited as long as it is a support that can form an electrode material film on the surface. In particular, from the viewpoint of continuously forming an electrode material film, a long-sized support is preferably used. In the case of a long-sized support, its width can be determined by the width (length) of the central portion of the width direction of the size of the electrode material film and the molding component (e.g., a scraper).

[0143] As the support, specifically, a current collector is mentioned as a preferred support.

[0144] The current collector which is an example of the support is not particularly limited, and a known current collector (positive electrode current collector and negative electrode current collector) can be used.

[0145] Examples of the positive electrode current collector include aluminum, aluminum alloys, stainless steel, nickel, and titanium. The positive electrode current collector is preferably aluminum or an aluminum alloy. The positive electrode current collector may be aluminum having a coating layer containing one or more of carbon, nickel, titanium, silver, gold, platinum, and vanadium oxide on the surface.

[0146] Examples of the negative electrode current collector include aluminum, copper, copper alloys, stainless steel, nickel, and titanium. The negative electrode current collector is preferably aluminum, copper, copper alloys, or stainless steel, more preferably copper or a copper alloy. The negative electrode current collector may be copper or stainless steel having a coating layer containing one or more of carbon, nickel, titanium, silver, and lithium on the surface.

[0147] As the current collector, aluminum foil (including aluminum foil having the above-mentioned coating layer on the surface) and copper foil (including copper foil having the above-mentioned coating layer on the surface) are preferred. Usually, aluminum foil is used as the current collector in the positive electrode. Usually, copper foil is used as the current collector in the negative electrode.

[0148] Furthermore, the support may be a laminate of a metal layer and a resin film exemplified as the above-mentioned positive electrode collector or negative electrode collector. As the resin film used for the laminate, there can be cited resin films such as 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.

[0149] Furthermore, as an example of the support, a release material can be mentioned.

[0150] Examples of the release material as an example of the support include release paper (for example, release paper manufactured by LINTEC Corporation), a film having a release layer, and paper having a release layer. Among them, release paper is preferred.

[0151] Furthermore, when a release material is used as the support, the electrode material film formed on the release material can be transferred to the current collector by utilizing the releasability of the release material.

[0152] From the viewpoint of transportability and the like, the average thickness of the support (preferably a current collector) is preferably 3 μm or more, more preferably 5 μm or more, and particularly preferably 10 μm or more.

[0153] From the viewpoint of flexibility and lightness, the average thickness is preferably 100 μm or less, more preferably 70 μm or less, and particularly preferably 50 μm or less.

[0154] The average thickness of the support is the arithmetic average of thicknesses at three locations measured by cross-sectional observation. A known microscope (for example, a scanning electron microscope) can be used for cross-sectional observation.

[0155] The size of the support is not limited and may be determined according to the size of the electrode molded body to be produced, the sizes of various members used in the production process, and the like.

[0156] Furthermore, in this step, there is no limitation on the conveying mechanism of the support, and a known conveying mechanism can be used.

[0157] As a conveying mechanism for the support body, for example, a belt conveyor, a linear slide guide, a cross roller conveyor, etc. can be used.

[0158] [Molding parts]

[0159] Examples of the molding member include scrapers and rollers, of which scrapers are preferred from the viewpoint of efficiently combining the lumps.

[0160] (Scraper)

[0161] The scraper is a component with a plate-like shape, but the shape, size, material, etc. of the contact part that contacts the block can be appropriately determined according to the type of electrode material (type of electrode active material, solid content concentration, composition of electrolyte (viscosity, surface tension), etc.), the size and thickness of the electrode material film formed, etc.

[0162] Furthermore, it is preferred that the electrode material is not easily attached to the contact portion of the scraper with the block, and for example, it is preferred that at least the surface of the scraper exhibits mold releasability.

[0163] For example, the scraper may be made of fluorine-based resin such as polytetrafluoroethylene (PTFE), resin such as polyetheretherketone (PEEK), metal such as stainless steel, aluminum, iron, superhard alloy, or ceramic.

[0164] Furthermore, in order to impart mold release properties to the surface, the blade may include a surface layer exhibiting mold release properties (for example, a surface layer containing a fluorine-based resin, a surface layer containing silicon-based particles and a resin).

[0165] Furthermore, from the viewpoint of improving the friction resistance, the blade may have a high hardness coating of titanium oxide, titanium nitride (TiN), tungsten carbide or the like on the metal or ceramic blade body.

[0166] In this step, from the viewpoint of obtaining an electrode material film with less variation in thickness, the friction coefficient μ1 between the contact portion of the scraper with the block and the electrode material is preferably smaller than the friction coefficient μ2 between the electrode material and the support.

[0167] In this way, it is presumed that by satisfying the relationship of the friction coefficient μ1<the friction coefficient μ2, the electrode material, which is a lump, is easily attached to the support side, and as a result, an electrode material film with less variation in thickness can be obtained.

[0168] The friction coefficient μ1 and the friction coefficient μ2 are obtained by forming an electrode material layer from an electrode material and measuring the friction coefficient between the electrode material layer and a blade or a support.

[0169] Specifically, first, 5 to 20 g of the electrode material is filled into a battery (size: cylinder with a diameter of 20 to 30 mm and a height of 20 to 30 mm), and voids in the electrode material (ie, air) are removed to form an electrode material layer.

[0170] The obtained electrode material layer is placed on a scraper or a support, and a counterweight of 100 g to 1000 g is further placed on the electrode material layer. Then, the electrode material layer is slid laterally on the scraper or the support by a tensile tester (lateral sliding speed: 5 mm / sec). The friction coefficient is obtained by plotting the relationship between the load in the vertical direction based on the counterweight obtained by the lateral sliding and the resistance measured by the tensile tester.

[0171] In addition, when the scraper or support cannot be directly used for the above-mentioned measurement, only the surface of the scraper or support can be taken out, or a measurement sample having the same composition and surface properties as the surface of the scraper or support can be prepared and used for measurement.

[0172] The above measurement was performed in a dry room environment of 21° C. and 0% RH (dew point temperature −60° C.).

[0173] (Roller)

[0174] The roller is a component whose outer peripheral surface can rotate, but its size, material, etc. can be appropriately determined according to the type of electrode material (type of electrode active material, solid content concentration, composition of electrolyte (viscosity, surface tension), etc.), the size and thickness of the electrode material film formed, etc.

[0175] The material constituting the outer peripheral surface of the roller may be the same as that of the blade, and may have a surface layer exhibiting mold release properties.

[0176] The outer diameter of the roller is not particularly limited, but may be, for example, 20 mm to 30 mm.

[0177] Furthermore, since the roller rotates, the friction coefficient between its outer peripheral surface and the block can be considered to be 0. However, as a result, the adhesion to the block (ie, electrode material) may become high, so it is preferred to sandwich release paper between the block and the outer peripheral surface of the roller.

[0178] [Specific electrode materials]

[0179] Hereinafter, the specific electrode material will be described in detail.

[0180] The specific electrode material contains at least an electrode active material and an electrolyte, and has a solid content concentration of 20% to 90% by volume. The solid content concentration of the specific electrode material is preferably 30% to 80% by volume, more preferably 40% to 70% by volume, and further preferably 40% to 60% by volume.

[0181] (Electrode Active Material)

[0182] The electrode active material is a material that can absorb and release 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.

[0183] Examples of the electrode active material include a positive electrode active material and a negative electrode active material.

[0184] -Positive electrode active material-

[0185] The positive electrode active material is not limited, and a known electrode active material used in a positive electrode can be used. The positive electrode active material is preferably a positive electrode active material that can reversibly absorb and release lithium ions.

[0186] Specific examples of the positive electrode active material include transition metal oxides and elements that can form a complex with lithium (for example, sulfur). Among the above, the positive electrode active material is preferably a transition metal oxide.

[0187] 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).

[0188] 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.

[0189] Furthermore, the transition metal oxide may 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.

[0190] Examples of the transition metal oxide 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 halophosphate compounds, and lithium-containing transition metal silicate compounds.

[0191] Examples of transition metal oxides having a layered rock salt structure include LiCoO2 (lithium cobalt oxide [LCO]), LiNi2O2 (lithium nickel oxide), LiNi 0.85 Co 0.10 Al 0.05 O2 (nickel cobalt aluminum oxide [NCA]), LiNi 1 / 3Co 1 / 3 Mn 1 / 3 O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide).

[0192] Examples of transition metal oxides having a spinel structure include LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8.

[0193] As lithium-containing transition metal phosphate compounds, for example, there can be mentioned olivine-type iron phosphates (for example, LiFePO4 and Li3Fe2(PO4)3), pyrophosphate iron salts (for example, LiFeP2O7), cobalt phosphates (for example, LiCoPO4) and monoclinic NASICON-type vanadium phosphates (for example, Li3V2(PO4)3 (lithium vanadium phosphate)).

[0194] Examples of lithium-containing transition metal halophosphate compounds include iron fluorophosphates (eg, Li2FePO4F), manganese fluorophosphates (eg, Li2MnPO4F), and cobalt fluorophosphates (eg, Li2CoPO4F).

[0195] Examples of lithium-containing transition metal silicate compounds include Li 2 FeSiO 4 , Li 2 MnSiO 4 , and Li 2 CoSiO 4 .

[0196] The transition metal oxide is preferably a transition metal oxide having a layered rock salt structure, and more preferably selected from LiCoO2 (lithium cobalt oxide [LCO]), LiNi 0.85 Co 0.10 Al 0.05 O2 (nickel cobalt aluminum oxide [NCA]) and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 At least one compound selected from the group consisting of O2 (lithium nickel manganese cobalt oxide [NMC]).

[0197] The positive electrode active material may be a commercial product or a synthetic product produced by a known method (eg, calcination method). For example, the positive electrode active material obtained by calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution or an organic solvent.

[0198] Furthermore, the positive electrode active material may have a carbon coating on its surface.

[0199] The shape of the positive electrode active material is not limited, but is preferably in the form of particles from the viewpoint of handleability.

[0200] The volume average particle size of the positive electrode active material is not 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.

[0201] The volume average particle size of the positive electrode active material is 0.3 μm or more, so that the aggregate of the electrode material can be easily formed and the splashing of the electrode material can be suppressed during operation. The volume average particle size of the positive electrode active material is 40 μm or less, so that the thickness of the electrode molded body can be easily adjusted and the generation of voids during the molding process can be suppressed.

[0202] The volume average particle size of the positive electrode active material is measured by the following method.

[0203] A dispersion containing less than 0.1% by mass of a positive electrode active material is prepared by mixing a positive electrode active material with a solvent (e.g., pure water, ethanol, heptane, octane, toluene or xylene). The dispersion irradiated with 1kHz ultrasonic waves for 10 minutes is set as a measurement sample. Using a laser diffraction / scattering particle size distribution measuring device (e.g., LA-960 manufactured by HORIBA, Ltd.) and at a temperature of 25°C, 50 data readings are performed, and the volume average particle size is calculated based on the volume frequency particle size distribution. A quartz colorimetric cell is used in the measuring cell. The above measurement is performed using 5 samples, and the average of the measured values ​​is set as the volume average particle size of the positive electrode active material. For other detailed conditions, refer to "JIS Z8828:2013" as needed.

[0204] As a method for adjusting the particle size of the positive electrode active material, for example, there can be mentioned a method using a pulverizer, a disintegrator, or a classifier. Also, as a method for adjusting the particle size of the positive electrode active material, a known grinding method can be applied.

[0205] The produced electrode material may contain a single positive electrode active material, or may contain two or more positive electrode active materials.

[0206] Furthermore, even when the electrode material to be produced contains one type of positive electrode active material, positive electrode active materials having different particle sizes may be used in combination.

[0207] The content of the positive electrode active material relative to the total volume of the produced electrode material is preferably 30 to 60 volume %, more preferably 35 to 55 volume %, and even more preferably 40 to 50 volume %.

[0208] -Negative electrode active material-

[0209] The negative electrode active material is not limited, and a known electrode active material used in a negative electrode can be used. The negative electrode active material is preferably a negative electrode active material that can reversibly absorb and release lithium ions.

[0210] As the negative electrode active material, for example, carbonaceous materials, metal oxides (for example, tin oxide), silicon oxide, metal composite oxides, lithium monomers, lithium alloys (for example, lithium aluminum alloys) and metals that can form alloys with lithium (for example, Sn, Si and In) can be cited. Among the above, from the viewpoint of reliability, the negative electrode active material is preferably a carbonaceous material or a lithium composite oxide.

[0211] Carbonaceous materials are materials consisting substantially of carbon.

[0212] 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 carbon fibers, cellulose carbon fibers, pitch carbon fibers, vapor-grown carbon fibers, dehydrated PVA (polyvinyl alcohol) carbon fibers, lignin carbon fibers, glassy carbon fibers, and activated carbon fibers). Examples of graphite include mesophase microspheres, graphite whiskers, and flat graphite.

[0213] In the present invention, "flat plate shape" means a shape having two main planes facing in opposite directions.

[0214] As the metal composite oxide, a metal composite oxide capable of occluding and releasing lithium is preferred.

[0215] From the viewpoint of high current density charge and discharge characteristics, the metal composite oxide capable of occluding and releasing lithium preferably contains at least one element selected from the group consisting of titanium and lithium.

[0216] The metal oxide and the metal composite oxide are particularly preferably amorphous oxides.

[0217] The metal oxide and the metal composite oxide are also preferably chalcogenides. Chalcogenides are reaction products between metal elements and elements of Group 16 in the periodic table.

[0218] Among the compound group consisting of amorphous oxides and chalcogenides, amorphous oxides and chalcogenides of semimetallic elements are also preferred, and oxides and chalcogenides of 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.

[0219] The negative electrode active material preferably further contains titanium. The volume change during the storage and release of lithium ions is small, so the rapid charge and discharge characteristics are excellent, and from the perspective of suppressing the degradation of the electrode and increasing the life of the lithium ion secondary battery, the negative electrode active material containing titanium is preferably Li4Ti5O 12 (lithium titanate [LTO]).

[0220] The negative electrode active material may be a commercial product or a synthetic product produced by a known method (eg, calcination method). For example, the negative electrode active material obtained by calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution or an organic solvent.

[0221] The negative electrode active material is available as, for example, CGB20 (Nippon Graphite Industry Co., Ltd.).

[0222] The composition of the negative electrode active material was measured using inductively coupled plasma (ICP) emission spectrometry.

[0223] The shape of the negative electrode active material is not limited, but is preferably in the form of particles from the viewpoint of easy handling and easy control of uniformity during mass production.

[0224] 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.

[0225] The volume average particle size of the negative electrode active material is measured by a method based on the method for measuring the volume average particle size of the positive electrode active material described above.

[0226] Examples of methods for adjusting the particle size of the negative electrode active material include a method using a pulverizer or a classifier.

[0227] The manufactured electrode material may contain a single negative electrode active material, or may contain two or more negative electrode active materials.

[0228] The content of the negative electrode active material relative to the total volume of the produced electrode material is preferably 30 to 60 volume %, more preferably 35 to 57 volume %, and even more preferably 45 to 55 volume %.

[0229] The surfaces of the positive electrode active material and the negative electrode active material may be coated with a surface coating agent, respectively. As the surface coating agent, for example, a metal oxide containing Ti, Nb, Ta, W, Zr, Si or Li may be cited. As the above-mentioned metal oxide, for example, titanate spinel, tantalum oxide, niobium oxide and lithium niobate compounds may be cited.

[0230] (Electrolyte)

[0231] There is no particular limitation on the electrolyte, and a known electrolyte can be used. For example, an electrolyte containing an electrolyte and a solvent can be cited. As a specific electrolyte, for example, an electrolyte containing a lithium salt compound as an electrolyte and a carbonate compound as a solvent can be cited.

[0232] As the lithium salt compound, for example, lithium hexafluorophosphate can be mentioned. The electrolyte solution may contain a single lithium salt compound, or may contain two or more lithium salt compounds.

[0233] As carbonate compounds, for example, chain carbonate compounds such as ethyl methyl carbonate (also referred to as EMC), dimethyl carbonate (also referred to as DMC), diethyl carbonate (DEC) and cyclic carbonate compounds such as ethylene carbonate (also referred to as EC) and propylene carbonate (also referred to as PC) can be cited. The electrolyte can include a single carbonate compound, can include two or more carbonate compounds, and can also use more than one chain carbonate compound and more than one cyclic carbonate compound simultaneously.

[0234] As the electrolyte contained in the electrolytic solution, for example, a well-known inorganic solid electrolyte can be used.

[0235] As a component of the electrolytic solution, for example, an ionic liquid can be used. The ionic liquid can be used as an electrolyte or as a solvent.

[0236] The content of the electrolyte relative to the total volume of the manufactured electrode material is preferably 80 volume % or less, more preferably 70 volume % or less, and further preferably 60 volume % or less. The content of the electrolyte in the electrode material is 80 volume % or less, thereby being able to suppress the electrolyte from seeping out when the electrode material is formed.

[0237] The lower limit of the content of the electrolyte in the electrode material may be more than 0 volume %, and is preferably 10 volume % or more.

[0238] The produced electrode material may contain, as a liquid component, a solvent other than the solvent contained as a component of the electrolytic solution (hereinafter, also simply referred to as a “solvent”).

[0239] 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.

[0240] The boiling point of the solvent is preferably 50° C. or higher, more preferably 70° C. or higher, at normal pressure (ie, 1 atmosphere). The upper limit of the boiling point of the solvent is preferably 250° C. or lower, more preferably 220° C. or lower, at normal pressure (ie, 1 atmosphere).

[0241] The produced electrode material may contain a single solvent or two or more solvents.

[0242] The content of the liquid component (ie, the electrolyte solution and the solvent) relative to the total volume of the produced electrode material is preferably 80 volume % or less, more preferably 70 volume % or less, and even more preferably 60 volume % or less.

[0243] The content of the liquid component in the electrode material is 80% by volume or less, thereby preventing the liquid component from seeping out when the electrode material is molded. Furthermore, when the liquid component contains a solvent, degradation of battery performance can be prevented.

[0244] The lower limit of the content of the liquid component in the electrode material may be more than 0 volume %, and is preferably 10 volume % or more.

[0245] In addition, the liquid component in the electrode material, that is, the component in the electrode material that is liquid at 25° C. is preferably liquid even at -10° C., and preferably liquid even at -20° C. That is, the component in the electrode material that is liquid at 25° C. is preferably a component that does not solidify at -10° C., and preferably a component that does not solidify at -20° C.

[0246] (Conductive additive)

[0247] From the viewpoint of improving the electron conductivity of the electrode active material, the produced electrode material preferably contains a conductive auxiliary agent. The conductive auxiliary agent is not limited, and a known conductive auxiliary agent can be used.

[0248] The conductive auxiliary agent is contained in the solid component.

[0249] As conductive aids, for example, graphite (for example, natural graphite and artificial graphite), carbon black (for example, acetylene black, Ketjen black and furnace black), amorphous carbon (for example, needle coke), carbon fiber (for example, vapor-grown carbon fiber and carbon nanotube), other carbonaceous materials (for example, graphene and fullerene), metal powder (for example, copper powder and nickel powder), metal fiber (for example, copper fiber and nickel fiber) and conductive polymer (for example, polyaniline, polypyrrole, polythiophene, polyacetylene and polyphenylene derivatives) can be cited.

[0250] The produced electrode material may contain a single conductive additive or two or more conductive additives.

[0251] When the manufactured electrode material contains a conductive aid, from the viewpoint of improving the electronic conductivity of the electrode active material, the content of the conductive aid is preferably 0.05 volume % to 5 volume %, more preferably 0.1 volume % to 4 volume %, and further preferably 0.5 volume % to 3 volume % relative to the total volume of the electrode material.

[0252] (Other ingredients)

[0253] The produced electrode material may contain a binder, a dispersant, other additives, etc. in addition to the above components.

[0254] Examples of the binder include fluorine-containing resins, hydrocarbon thermoplastic resins, acrylic resins, and urethane resins.

[0255] Furthermore, the dispersant may be any known dispersant as long as it can disperse the dispersion object.

[0256] Furthermore, as other additives, known additives added to electrode materials can be used.

[0257] (Method for preparing electrode material)

[0258] The electrode material can be prepared by, for example, mixing an electrode active material, an electrolyte solution, and other components used as necessary.

[0259] Examples of the mixing method include methods using a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, or a disk mill.

[0260] <<Molded article for sheet electrode>>

[0261] The sheet electrode molded body obtained by the method for producing a sheet electrode molded body according to the present invention can be used as various electrodes.

[0262] The sheet-shaped molded body for an electrode is preferably a molded body for an electrode of a semi-solid secondary battery.

[0263] From the viewpoint of improving battery performance (for example, discharge capacity and output characteristics), the average thickness of the sheet-like electrode molded body is preferably 0.01 mm to 2 mm, more preferably 0.05 mm to 1.5 mm, and particularly preferably 0.1 mm to 1 mm.

[0264] The average thickness of the electrode molded body is measured by the same method as the average thickness of the support.

[0265] Example

[0266] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.

[0267] [Preparation of positive electrode material (P1)]

[0268] (1) After LiPF6 (electrolyte) was mixed into a mixed solution of ethylene carbonate (EC), propylene carbonate (PC) and diethyl carbonate (DEC), vinylene carbonate (VC) was further mixed in. 64 g of the obtained mixed solution was taken out and used as electrolyte X1.

[0269] (2) Using a mixer (Awatori Rentaro ARE-310, manufactured by THINKY CORPORATION), 2 g of a conductive aid (Ketjen Black) and 174 g of a positive electrode active material (lithium iron phosphate) were stirred at 1500 rpm (revolutions per minute, the same applies hereinafter) for 30 seconds to prepare a kneaded product Y1 (176 g).

[0270] (3) Electrolyte X1 (64 g) was added to kneaded product Y1 (176 g), and the mixture was stirred at 1500 rpm for 120 seconds using a mixer (Awatori Rentaro ARE-310, manufactured by THINKY CORPORATION) to obtain a positive electrode material (P1).

[0271] The volume ratio of the solid content to the liquid content of the obtained positive electrode material (P1) was 48:52.

[0272] The positive electrode material (P1) was extruded using a chopper (manufactured by Bonny Co., Ltd.) to obtain a mass (P1) consisting of cylindrical (diameter: 3 mm to 5 mm) granules.

[0273] [Preparation of support]

[0274] Support (S1): positive electrode current collector (aluminum foil)

[0275] [Preparation of molded parts]

[0276] Scraper (B1): Stainless steel scraper

[0277] <Example 1>

[0278] A previously produced mass (P1) is spread and supplied on a continuously conveyed support (S1), and a plurality of masses are dispersedly arranged on the support (step A).

[0279] The average height of the plurality of blocks dispersed on the support was 3 mm, the diameter was 3 mm to 5 mm, the distance between the area centers of adjacent blocks (distance D) was 10 mm, and the area ratio was 15%.

[0280] like Figure 4 and Figure 5 As shown in FIG. 1 , the scraper 30 is arranged so that the distance C between the surface of the support 10 and the front end of the scraper 30 is set to 0.3 mm. Figure 4 and Figure 5 As shown in the figure, the support 10 is transported and moved along the arrow X direction, and a plurality of blocks 20 dispersedly arranged on the support 10 are brought into contact with the scraper 30 and passed through a gap having a distance C. Thus, an electrode material film 24 is formed as a continuous film on the support 10 along the transport direction (arrow X direction) of the support 10. The film thickness of the obtained electrode material film 24 is 0.3 mm.

[0281] As described above, the ratio (H / C) is 10. Furthermore, when the electrode material film is formed as a continuous film, the ratio (Y / X) satisfies 1≤Y / X≤5 on a volume basis.

[0282] In Example 1, the pressure applied from the scraper as the molding member to the electrode material (lump (P1)) was 100 kPa.

[0283] <Comparative Example 1>

[0284] Prepared as Japanese Patent Publication No. 2021-027043 Figure 2 The hopper shown in the figure has a nozzle with an opening width of 200 mm and an opening height of 1 mm for discharging the electrode material. The positive electrode material (P1) is placed in the hopper, and the positive electrode material (P1) is discharged from the nozzle onto the support body that is being transported and moved. Thus, an electrode material film with a film thickness of 1 mm is formed on the support body.

[0285] In Comparative Example 1, the pressure applied to the electrode material when discharged from the nozzle was 10,000 kPa.

[0286] As described above, it can be seen that in Example 1, the pressure applied from the molded component to the electrode material (lump) is 100 times or more of the pressure applied to the electrode material in Comparative Example 1.

[0287] This shows that, in the method for producing a sheet-like electrode molded body according to the present invention, it is possible to produce a sheet-like electrode molded body having a target thickness while reducing the load applied to the electrode material.

[0288] Explanation of symbols

[0289] 10-support, 20-block, 20C-area center of gravity, 22-granular material, 24-electrode material film, 30-scraper, C-distance between the scraper and the support surface, D-distance between the area centers of gravity of adjacent blocks, H-height of the block, X-conveying direction of the support.

[0290] The invention of Japanese Patent Application No. 2022-120971 filed on July 28, 2022 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard were specifically and individually described by reference.

Claims

1. A method for producing a sheet-shaped electrode molded body, comprising: Step A, dispersing a plurality of blocks of an electrode material including an electrode active material and an electrolyte and having a solid content concentration of 20 volume % to 90 volume % on a support; and In step B, a plurality of blocks dispersedly arranged on a support are combined by a molding component to form an electrode material film on the support.

2. The method for producing a sheet-shaped electrode molded body according to claim 1, wherein: By moving the molding member relatively along the surface of the support while maintaining a constant distance from the surface of the support, a plurality of blocks dispersed on the support are combined to form an electrode material film on the support.

3. The method for producing a sheet-shaped electrode molded body according to claim 2, wherein: When the average height of the plurality of blocks dispersed on the support is H and the distance between the molding component and the support surface is C, the ratio of the height H to the distance C, ie, H / C, satisfies 1<H / C≤100.

4. The method for producing a sheet-shaped electrode molded body according to claim 1 or 2, wherein: The pressure applied from the molded part to the electrode material is 10 kPa to 500 kPa.

5. The method for producing a sheet-shaped electrode molded body according to claim 1 or 2, wherein: Among the plurality of blocks dispersedly arranged on the support, the distance between the area centers of gravity of adjacent blocks is 0.1 mm to 50 mm.

6. The method for producing a sheet-shaped electrode molded body according to claim 1 or 2, wherein: The area occupied by the plurality of masses dispersedly arranged on the support is 10% to 90% of the area where the electrode material film is formed on the support.

7. The method for producing a sheet-shaped electrode molded body according to claim 1 or 2, wherein: Step A is performed by scattering and supplying a plurality of lumps of an electrode material containing an electrode active material and an electrolyte solution and having a solid content concentration of 20 volume % to 90 volume % onto a support.

8. The method for producing a sheet-shaped electrode molded body according to claim 1 or 2, wherein: The step A and the step B are performed using the support being continuously transported, and in the step B, the electrode material film is formed as a continuous film along the transport direction of the support.

9. The method for producing a sheet-shaped electrode molded body according to claim 7, wherein: When the theoretical amount of electrode material that can form an electrode material film with a thickness equal to the distance between the molding component and the surface of the support body and without a gap is X, and the supply amount of the block of electrode material supplied to the support body is Y, the ratio of the supply amount Y to the amount X, i.e. Y / X, satisfies 1≤Y / X≤5 on a volume basis.

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