Method and apparatus for manufacturing powder molded body

Abstract

To provide a method for manufacturing a powder molded body capable of producing a powder molded body having a thin and uniform thickness.SOLUTION: A method for manufacturing a powder molded body comprises preparing a molding die 10 having a cylindrical molding mortar 11, a mallet 12, and a mallet 13, and a powder-leveling tool 20. The mallet 12 is inserted into the interior of the molding mortar 11 to close one opening. A nozzle 30 is inserted from the other opening of the molding mortar 11, and a powder material X1 is supplied. The powder-leveling tool 20 is inserted from the other opening of the molding mortar 11, and the powder material X1 is flattened by pressing the powder-leveling tool 20 downward while rotating it. Instead of the powder-leveling tool 20, the mallet 13 is inserted into the interior of the molding mortar 11 and pressed downward to compress the powder material X1. By flattening the powder material X1 while spreading it with the powder-leveling tool 20 before compressing the powder material X1, a powder molded body (solid electrolyte layer 4) having a thin and uniform thickness can be obtained.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for manufacturing a powder compact, particularly a laminated electrode body to be built into an all-solid-state battery. [Background technology]

[0002] An all-solid-state battery is assembled by housing a stacked electrode assembly, which has a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between them, in a battery container. The stacked electrode assembly is formed by pressing a powdered electrode material for forming the positive electrode layer, a powdered electrode material for forming the negative electrode layer, and a powdered solid electrolyte material.

[0003] The solid electrolyte layer of the laminated electrode body is preferably relatively thin in order to improve battery capacity. However, when an attempt is made to form a thin solid electrolyte layer, the laminated electrode body is prone to cracking during pressure molding. Furthermore, the solid electrolyte layer is more prone to unevenness when pressure molded than when formed relatively thick. Therefore, it is difficult to achieve a uniform thickness for the solid electrolyte layer. Cracks in the laminated electrode body and uneven thickness of the solid electrolyte layer can cause internal short circuits and the like, which can degrade the battery performance of the all-solid-state battery.

[0004] Japanese Patent Laid-Open Publication No. 2004-356041 (Patent Document 1) discloses a method for manufacturing an all-solid-state battery. In this method for manufacturing an all-solid-state battery in which a power generating element is housed in a case, the outer mold for the power generating element is composed of two parts that can be separated at a separation part, and a green compact in which the three layers are integrated is formed in a molding hole with a solid electrolyte layer disposed in the part that contacts the separation part, and the outer mold is separated to remove the green compact from the molding hole. This makes it possible to manufacture a power generating element consisting of three layers in which the interfaces of the positive electrode composite layer, solid electrolyte layer, and negative electrode composite layer are firmly bonded together with high reliability while suppressing internal short circuits.

[0005] Japanese Patent Laid-Open Publication No. 2-89597 (Patent Document 2) discloses a method for producing high-density green compacts. This method involves filling a pressure cylinder with powder or granular material such as metal or ceramics and compressing it, and then rotating the surface of the pressure cylinder that comes into contact with the powder or granular material inside the pressure cylinder around the axis of the container to apply a shear force to the powder or granular material in the rotational direction. This changes the position of the powder or granular particles, reducing the porosity and allowing for the production of high-density green compacts with few pores and high strength.

[0006] Japanese Patent Laid-Open Publication No. 9-292319 (Patent Document 3) discloses a powder molding method and molding device. In the powder molding method, a powder sample is placed in a mold, and the pressure unit of the molding device is rotated or vibrated for a predetermined period of time to pressure-mold the powder sample in the mold. This smooths the surface of the sample in the mold, and then pressurizes it, preventing cracks on the sample surface. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-356041 [Patent Document 2] Japanese Patent Application Publication No. 2-89597 [Patent Document 3] Japanese Patent Application Publication No. 9-292319 Summary of the Invention [Problem to be solved by the invention]

[0008] The manufacturing method of an all-solid-state battery in Patent Document 1 and the manufacturing method of a high-density powder in Patent Document 2 do not consider forming the power generating element and the green compact to a thin and uniform thickness. As described above, when the powder compact is a laminated electrode body, it is important to form the powder laminate to a thin and uniform thickness from the viewpoints of improving battery capacity and suppressing internal short circuits.

[0009] The powder molding method of Patent Document 3 equalizes the powder sample by vibrating or rotating the pressurizing unit. However, the pressurizing unit is designed solely for the purpose of pressing the powder sample, and does not necessarily equalize the powder sample appropriately. In other words, there is room for further study to more appropriately equalize the powder sample.

[0010] Therefore, an object of the present disclosure is to provide a powder molded body manufacturing method and a manufacturing method that can manufacture powder molded bodies that are thin and have a uniform thickness. [Means for solving the problem]

[0011] In order to solve the above problems, the present disclosure is configured as follows: That is, a method for manufacturing a powder molded body according to the present disclosure includes the steps of preparing a molding die having a cylindrical molding dies and a first punch inserted through a first opening of the molding dies, and preparing a powder leveling tool inserted through the first opening of the molding dies, pouring powder material into the molding dies through the first opening of the molding dies and arranging the powder material inside the molding dies, inserting the powder leveling tool through the first opening of the molding dies and pressing down the powder leveling tool while rotating at least one of the powder leveling tool and the interior of the molding dies in a circumferential direction to flatten the powder material, and removing the powder leveling tool from the interior of the molding dies, and then inserting the first punch through the first opening of the molding dies and pressing the flattened powder material.

[0012] The present disclosure also provides a powder molding manufacturing apparatus that includes a molding die and a powder leveling tool. The molding die includes a cylindrical molding die having a first opening, and a first punch that is inserted through the first opening of the molding die to apply pressure to the powder material disposed inside the molding die. The powder leveling tool is inserted through the first opening of the molding die to flatten the powder material disposed inside the molding die before applying pressure. [Effects of the Invention]

[0013] According to the method and apparatus for producing a powder molded body according to the present disclosure, a powder molded body having a thin and uniform thickness can be produced. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an external perspective view showing a laminated electrode body according to the present disclosure. [Figure 2] FIG. 2 is a flowchart showing a method for producing a powder molded body according to the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view showing a preparation step of the molding die shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing the inserting step of the punch shown in FIG. [Figure 5] 5A to 5C are cross-sectional views showing an inserting step of the nozzle shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view showing a step of adding the powder material shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing a step of flattening the powder material shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view showing a step of pressing the powder material shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view showing a planarizing step of the solid electrolyte material. [Figure 10] FIG. 10 is a cross-sectional view showing the state after the solid electrolyte layer has been formed. [Figure 11] FIG. 11 is a cross-sectional view showing a step of flattening the positive electrode mixture. [Figure 12] FIG. 12 is a perspective view showing the powder leveling tool of Examples 1 and 2. As shown in FIG. [Figure 13] FIG. 13 is a perspective view showing the punches of Comparative Examples 1 and 2. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Configuration 1) The method for manufacturing powder molded bodies according to this embodiment includes the steps of preparing a molding die having a cylindrical molding dies and a first punch inserted through the first opening of the molding dies, and a powder leveling tool inserted through the first opening of the molding dies; pouring powder material into the interior of the molding dies through the first opening of the molding dies and arranging the powder material inside the molding dies; inserting the powder leveling tool through the first opening of the molding dies and pressing down the powder leveling tool while rotating at least one of the powder leveling tool and the interior of the molding dies in a circumferential direction to flatten the powder material; and removing the powder leveling tool from the interior of the molding dies, inserting the first punch through the first opening of the molding dies and pressing the flattened powder material.

[0016] A powder leveling tool for leveling the powder material is provided separately from the first pestle that pressurizes the powder material, and before pressing the powder material, the powder leveling tool is pressed down while at least one of the powder leveling tool and the inside of the molding mortar is rotated circumferentially, and a predetermined load is applied to the powder material, thereby allowing the powder material to be sufficiently and appropriately flattened while being spread out, and as a result, a powder molded body with a thin and uniform thickness can be produced.

[0017] (Configuration 2) In the method for producing a powder molded body of Configuration 1, the molding die may have a second opening on the opposite side of the first opening of the molding die. The molding die may further have a second pestle inserted through the second opening of the molding die. Before the step of introducing the powder material into the molding die, the method may include the step of inserting the second pestle through the second opening of the molding die and closing the second opening of the molding die. In the step of placing the powder material inside the molding die, the powder material may be placed above the second pestle.

[0018] (Configuration 3) In the method for producing a powder molded body according to the first or second aspect, the powder material may be placed inside the forming die (e.g., above the second pestle) so as to form a convex shape. By placing the powder material in a convex shape, it becomes easier to flatten the powder material. This makes it possible to more effectively produce a powder molded body having a thin and uniform thickness.

[0019] (Configuration 4) In the method for producing a powder molded body according to any one of configurations 1 to 3, in the step of pressing down a powder leveling tool to level the powder material, a gap may be formed between the powder leveling tool and the forming dies. When the inner diameter of the forming dies is d1, the outer diameter of the powder leveling tool is d2, and the gap is defined as "(d1-d2) / 2," the gap may be 0.05 mm or more and 10% or less of the inner diameter d1. By forming a gap in this manner, the powder material can be more appropriately leveled.

[0020] (Configuration 5) In the method for producing a powder molded body according to any one of the first to fourth aspects, in the step of pressing down the powder leveling tool to flatten the powder material, the load applied is 3 gf / cm 2 ~30gf / cm 2 This allows the powder material to be more effectively and appropriately flattened, and a thin and uniform powder molded body to be manufactured.

[0021] (Configuration 6) In the method for producing a powder molded body according to any one of aspects 1 to 5, the powder molded body may be any one of an anode layer, a solid electrolyte layer, and a cathode layer of a laminated electrode body to be built into an all-solid-state battery. The powder material may be a powder material for forming any one of the anode layer, the solid electrolyte layer, and the cathode layer. This allows any one of the anode layer, the solid electrolyte layer, and the cathode layer to be formed thin, thereby improving the battery capacity of the all-solid-state battery. Furthermore, by forming the solid electrolyte layer to a uniform thickness, internal short circuits can be suppressed.

[0022] (Configuration 7) In the method for producing a powder molded body according to Configuration 6, the molding die may have an inner diameter of 5 mm to 50 mm, which can increase the battery capacity of the all-solid-state battery and suppress the internal resistance.

[0023] (Configuration 8) The powder molding manufacturing apparatus according to this embodiment includes a molding die and a powder leveling tool. The molding die includes a cylindrical molding die having a first opening, and a first punch that is inserted through the first opening of the molding die to pressurize the powder material placed inside the molding die. The powder leveling tool is inserted through the first opening of the molding die to flatten the powder material placed inside the molding die before pressing.

[0024] By providing a powder leveling tool for flattening the powder material separately from the first pestle that pressurizes the powder material, the powder material can be flattened sufficiently and appropriately, and as a result, a powder molded body with a thin and uniform thickness can be produced.

[0025] (Configuration 9) In the apparatus for manufacturing a powder molded body of Configuration 8, the molding die may have a second opening on the opposite side of the first opening of the molding die. The molding die may further have a second pestle inserted through the second opening of the molding die. Before the step of charging the powder material into the molding die, the method may include the step of inserting the second pestle through the second opening of the molding die and closing the second opening of the molding die. In the step of placing the powder material inside the molding die, the powder material may be placed above the second pestle.

[0026] (Configuration 10) In the powder molding manufacturing apparatus of Configuration 8 or 9, when the powder leveling tool is inserted inside the forming dies, a gap may be formed between the powder leveling tool and the forming dies. When the inner diameter of the forming dies is d1 and the outer diameter of the powder leveling tool is d2, and the gap is defined as "(d1-d2) / 2", the gap may be 0.05 mm or more and 10% or less of the inner diameter d1. By forming a gap in this manner, the powder material can be more appropriately flattened.

[0027] (Configuration 11) In the powder molded body manufacturing apparatus of any one of Configurations 8 to 10, the powder molded body may be any one of an anode layer, a solid electrolyte layer, and a cathode layer of a laminated electrode body to be built into an all-solid-state battery. The powder material may be a powder material for forming any one of the anode layer, the solid electrolyte layer, and the cathode layer. This allows any one of the anode layer, the solid electrolyte layer, and the cathode layer to be formed thin, thereby improving the battery capacity of the all-solid-state battery. Furthermore, by forming the solid electrolyte layer to a uniform thickness, internal short circuits can be suppressed.

[0028] (Configuration 12) In the powder molding device of Configuration 11, the molding die may have an inner diameter of 5 mm to 50 mm, which can increase the battery capacity of the all-solid-state battery and suppress the internal resistance.

[0029] Hereinafter, first, a method for producing a powder molded body according to the present disclosure will be specifically described with reference to FIGS. 1 to 11. Here, a case where the powder molded body is a laminated electrode body built into an all-solid-state battery will be described. Note that the same or corresponding components in the drawings are given the same reference numerals, and the same description will not be repeated. Note that, to make the description easier to understand, the drawings referred to below show simplified or schematic configurations, and some components are omitted.

[0030] [Laminated electrode body] First, the laminated electrode body 1 is built into an all-solid-state battery (not shown). For example, the all-solid-state battery is a flat battery. The all-solid-state battery includes a case made up of an outer can, a sealing can, and a gasket, and the laminated electrode body 1 housed in the case.

[0031] As shown in FIG. 1 , the laminated electrode body 1 includes a positive electrode layer 2, a negative electrode layer 3, and a solid electrolyte layer 4 disposed between the positive electrode layer 2 and the negative electrode layer 3. The positive electrode layer 2, the negative electrode layer 3, and the solid electrolyte layer 4 have substantially similar circular shapes in a plan view, and are stacked in the order of the positive electrode layer 2, the solid electrolyte layer 4, and the negative electrode layer 3 from the bottom in the drawing. In other words, the laminated electrode body 1 has a cylindrical shape. Note that the shape of the laminated electrode body 1 is not limited to a cylindrical shape, and may be variously changed to a rectangular parallelepiped shape, a polygonal prism shape, or the like depending on the size and shape of the all-solid-state battery.

[0032] The positive electrode layer 2 is, for example, a positive electrode pellet obtained by placing 92 mg of a positive electrode mixture containing lithium cobalt oxide with an average particle size of 5 μm as a positive electrode active material used in lithium-ion secondary batteries, a sulfide-based solid electrolyte (Li6PS5Cl), and carbon nanotubes as a conductive additive in a mass ratio of 70:26:4 into an 8 mm diameter forming die (described later) and forming it into a cylindrical shape. The positive electrode layer 2 is not particularly limited as long as it can function as the positive electrode layer 2 of the laminated electrode body 1. For example, the positive electrode layer 2 may be lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, spinel-type manganese composite oxide, olivine-type composite oxide, or an appropriate mixture of these. The size and shape of the positive electrode layer 2 are not limited to a cylindrical shape and can be varied depending on the size and shape of the all-solid-state battery.

[0033] The negative electrode layer 3 is made of, for example, LTO (Li4Ti5O 12 The negative electrode pellet is obtained by placing 129 mg of a negative electrode mixture containing lithium ion battery (Li6PS5Cl), a sulfide-based solid electrolyte (Li6PS5Cl), and carbon nanotubes in a weight ratio of 50:41:9 into a molding die (described later) and forming it into a cylindrical shape. The negative electrode layer 3 is not particularly limited as long as it can function as the negative electrode layer 3 of the laminated electrode body 1, and may be made of, for example, metallic materials such as metallic lithium and lithium alloys, carbon materials such as graphite and low-crystalline carbon, or materials such as SiO, LTO (Li4Ti5O 12, lithium titanate), etc., or an appropriate mixture of these. The size and shape of the negative electrode layer 3 are not limited to a cylindrical shape, and can be changed in various ways depending on the size and shape of the all-solid-state battery.

[0034] The solid electrolyte layer 4 is disposed between the positive electrode layer 2 and the negative electrode layer 3. The solid electrolyte layer 4 is formed, for example, by placing 1 mg of a sulfide-based solid electrolyte (Li6PS5Cl) in a molding die (described later) and forming it into a cylindrical shape. The solid electrolyte layer 4 is not particularly limited, but may be other sulfide-based solid electrolytes such as argyrodite-type electrolytes in terms of ion conductivity. When using a sulfide-based solid electrolyte, it is preferable to coat the surface of the positive electrode active material with niobium oxide to prevent reaction with the positive electrode active material. The solid electrolyte layer 4 may also be a hydride-based solid electrolyte, an oxide-based solid electrolyte, or the like. The size and shape of the solid electrolyte layer 4 are not limited to a cylindrical shape and can be variously changed depending on the size and shape of the all-solid-state battery.

[0035] [Manufacturing method of laminated electrode body (powder compact)] Next, a method for manufacturing the laminated electrode body 1 will be specifically described with reference to Figures 3 to 11 and Figures 2. In this embodiment, as will be described later, the laminated electrode body 1, and the positive electrode layer 2, negative electrode layer 3, and solid electrolyte layer 4 constituting the laminated electrode body 1 are powder molded bodies obtained by pressure molding powder materials, such as a positive electrode mixture X3, a negative electrode mixture X2, and a solid electrolyte material X1.

[0036] [Formation of solid electrolyte layer] [Mold preparation process (S1)] First, as shown in FIG. 3, a molding die 10 and a powder leveling tool 20 are prepared. The molding die 10 includes a cylindrical molding die 11, a punch 12 (second punch) inserted into the molding die 11 from a lower opening (second opening) and sliding up and down, and a punch 13 (first punch) inserted into the molding die 11 from an upper opening (first opening) and sliding up and down. The molding die 11 is formed with a cylindrical opening from top to bottom. The punches 12 and 13 are each formed in a columnar shape that matches the shape of the opening of the molding die 11. The molding die 10 applies pressure to the powder material introduced into the molding die 11 by sliding the punches 12 and 13 up and down.

[0037] The powder leveling tool 20 has a leveling portion 21 having a leveling surface 21a for leveling the powder material introduced into the molding mortar 11, and a support portion 22 for supporting the leveling portion 21. The powder leveling tool 20 is inserted into the molding mortar 11 from an upper or lower opening and slides up and down. The powder leveling tool 20 is preferably made lighter than the pestle 13 or pestle 12. This makes it easier to adjust the load applied to the powder material to a small value in the flattening step S5 described below, and allows the conditions for pressing the powder material to be set more precisely.

[0038] [Punch insertion process (S2)] Next, as shown in FIG. 4, a punch 12 is inserted into the forming die 11 through the opening at the bottom of the forming die 11, and the opening at the bottom of the forming die 11 is closed with the punch 12.

[0039] [Nozzle insertion process (S3)] Next, as shown in Fig. 5, a nozzle 30 is inserted into the forming die 11 from an opening at the top of the forming die 11. The nozzle 30 is connected to a hopper (not shown). The powder material is filled in the hopper and is poured into the forming die 11 through the nozzle 30 as described below. Note that the nozzle 30 may be inserted from above the forming die 11 before the punch 12 is inserted below the forming die 11, and the order of the punch insertion step (S2) and the nozzle insertion step (S3) may be reversed.

[0040] [Powder material feeding process (S4)] Next, as shown in FIG. 6 , a solid electrolyte material (powder material) X1 is introduced into the forming die 11 through the nozzle 30. The solid electrolyte material X1 is placed on the forming surface 12a of the pestle 12. Preferably, the solid electrolyte material X1 is arranged on the forming surface 12a of the pestle 12 so as to form a convex shape. The convex shape is, for example, a substantially conical shape. Specifically, the nozzle 30 is placed with its injection hole inside the cylindrical forming die 11, i.e., at the axial center of the opening of the forming die 11, and the nozzle 30 is fixed while the powder material is being introduced. This allows the powder material to flow downward without segregating, naturally forming a convex shape. Arranging the powder material so as to form a convex shape makes it easier to flatten the powder material in the flattening step S5, which will be described later. The nozzle 30 is movable horizontally above the forming die 11. It moves above the forming die 11 when introducing the powder material and waits in a location other than above the forming die 11 when not introducing the powder material. That is, the nozzle 30 moves to a location other than above the forming die 11 after the powder material has been completely charged.

[0041] [Planarization process (S5)] Next, as shown in FIG. 7 , a powder leveling tool 20 is inserted through the upper opening of the forming die 11, and the leveling surface 21a of the leveling unit 21 is rotated in the circumferential direction, i.e., the insertion direction of the powder leveling tool 20 is rotated around the rotation axis A, and the solid electrolyte material X1 arranged on the forming surface 12a is pressed down to spread and flatten it. Here, flattening refers to uniformly flattening the upper surface of the powder material that contacts the leveling surface 21a of the leveling unit 21. For example, if the powder material is arranged so as to have a convex shape, it may be flattened to have a truncated cone shape. However, from the viewpoint of making the powder molded body thin and uniform, it is preferable to uniformly flatten the upper surface of the powder material so that the powder material has an approximately cylindrical shape. By flattening the solid electrolyte material (powder material) X1 in this way, the solid electrolyte material X1 is uniformly spread before the pressurizing process described below. Flattening can also be achieved by simply pressing down the leveling unit 21 without rotating it. However, from the viewpoint of obtaining a powder molded body with a more uniform thickness, it is preferable to flatten the powder material while rotating at least one of the leveling unit 21 and the interior of the forming dies 11. Either the leveling unit 21 or the interior of the forming dies 11 may be rotated, or both the leveling unit 21 and the interior of the forming dies 11 may be rotated. Here, rotating the interior of the forming dies 11 means rotating the powder material inside the forming dies 11.

[0042] At this time, the load applied to the solid electrolyte material (powder material) X1 by the leveling unit 21 that is pressed down while rotating is 3 gf / cm 2 ~30gf / cm 2 It is preferable to set the value to 5 gf / cm 2 ~20gf / cm 2 More preferably, 6 gf / cm 2 ~12gf / cm 2 It is particularly preferable that the load applied to the solid electrolyte material X1 is 3 gf / cm. If the load applied to the solid electrolyte material X1 is too small, it is difficult to properly flatten the solid electrolyte material X1. On the other hand, if the load applied to the solid electrolyte material X1 is too large, the solid electrolyte material X1 may be compressed before being properly flattened, or cracks may occur in the solid electrolyte layer 4. Therefore, from the viewpoint of properly flattening the solid electrolyte material X1, the load applied to the solid electrolyte material X1 is 3 gf / cm.2 It is preferable that it is 5 gf / cm or more. 2 More preferably, it is 6 gf / cm or more. 2 On the other hand, it is particularly preferable that the load applied to the solid electrolyte material X1 is 30 gf / cm or more. 2 It is preferable that it is less than 20 gf / cm 2 It is more preferable that it is 12 gf / cm or less. 2 It is particularly preferable to set the following: This makes it possible to more effectively flatten the solid electrolyte material X1 appropriately, and to manufacture a thin and uniform powder molded body.

[0043] When flattening the solid electrolyte material X1, at least one of the leveling unit 21 and the interior of the forming die 11 may be rotated multiple times, for example, eight times, five times, or three times. That is, at least one of the leveling unit 21 and the interior of the forming die 11 may be rotated intermittently. When rotating intermittently, from the viewpoint of preventing cracks or chips in the solid electrolyte layer 4, it is preferable that the rotation direction from the second time onwards is the same as the direction of the initial rotation.

[0044] As described above, the outer diameter d2 of the powder leveling tool 20 is smaller than the inner diameter d1 of the forming mortar 11. As shown in the figure, in this embodiment, the outer diameter of the leveling portion 21 is larger than the outer diameter of the support portion 22. Therefore, in this embodiment, the outer diameter d2 of the powder leveling tool 20 is the outer diameter of the leveling portion 21. Note that, when the outer diameter of the support portion 22 is smaller than the outer diameter of the leveling portion 21, the outer diameter d2 of the powder leveling tool 20 is the outer diameter of the support portion 22. As a result, when the powder leveling tool 20 is inserted into the forming mortar 11, a gap G is formed between the powder leveling tool 20 and the inner circumferential surface of the forming mortar 11. By forming the gap G, when the solid electrolyte material X1 is flattened and the powder leveling tool 20 is removed from inside the forming mortar 11, gas such as air below the leveling portion 21 passes through the gap G appropriately and escapes, thereby preventing the flattened solid electrolyte material X1 from being scattered. As a result, the powder material can be more appropriately flattened. If the outer diameter d2 varies depending on the location, for example, if the shape of the powder leveling tool 20 is not circular, the maximum value may be taken as the outer diameter d2.

[0045] From the viewpoint of suppressing the scattering of the flattened solid electrolyte material X1, the powder leveling tool 20, particularly the leveling part 21, can be made of a material that is excellent in antistatic properties and that is unlikely to generate static electricity. Examples of the antistatic material include metals (stainless steel, super steel, iron, aluminum, copper, etc.), antistatic grade resin, conductive grade resin, or resin with a metal-plated surface.

[0046] The gap G can be defined by the formula "(d1 - d2 / 2)" where d1 is the inner diameter of the forming dies 11 and d2 is the outer diameter of the powder leveling tool 20. If the gap G is too small, when the powder leveling tool 20 is removed from the inside of the forming dies 11, a relatively high-velocity airflow is generated by gas such as air passing through the gap G, which may cause the flattened solid electrolyte material X1 to scatter. Therefore, the gap G is set to 0.05 mm or more, preferably 0.1 mm or more, and more preferably 0.2 mm or more. On the other hand, if the gap G is too large (for example, if the outer diameter of the powder leveling tool 20 is too small), it becomes difficult to properly flatten the solid electrolyte material X1. Therefore, the gap G is set to 10% or less of the inner diameter d1 of the forming dies 11, preferably 5% or less, more preferably 3% or less, and particularly preferably 1.5% or less. As an example, if the inner diameter d1 of the forming dies 11 is 18.8 mm and the outer diameter of the powder leveling tool 20 is 18.5 mm, the gap G is 0.15 mm, and the ratio of the gap G to the inner diameter d1 is 0.8%. In the forming method of Patent Document 3, it is difficult to provide a gap between the pressurizing part and the inner surface of the mold. This is because providing a gap between the pressurizing part and the inner surface of the mold could cause the powder sample to leak out through the gap during pressure application.

[0047] When the powder molded body is a laminated electrode body 1, the inner diameter d1 of the forming die 11 is preferably 5 mm or more, more preferably 7 mm or more, in order to increase the battery capacity of the all-solid-state battery. However, if the area of ​​the laminated electrode body 1 in a plan view becomes too large, that is, if the inner diameter d1 becomes too large, the pressure applied in the pressurizing step S6 described below will become small, reducing the density of the laminated electrode body 1 and increasing its internal resistance. Therefore, the inner diameter d1 is preferably 50 mm or less, more preferably 25 mm. In other words, the inner diameter d1 is preferably 5 mm to 50 mm, more preferably 7 mm to 25 mm.

[0048] After the solid electrolyte material X1 is flattened, the powder leveling tool 20 is removed from the inside of the forming dies 11.

[0049] [Pressing step (S6)] 8, the punch 13 is inserted from the upper opening of the forming die 11 and pressed down to apply pressure to the solid electrolyte material X1 with the punches 12 and 13. At this time, the solid electrolyte material X1 is pressed down to a pressure of, for example, 1 tonf / cm 2 The solid electrolyte material X1 is pressed with a load of 0.01 MPa. In addition, in order to prevent cracks from occurring in the layer, it is desirable to press the pestle 13 in the axial direction without rotating it. In this way, by providing the flattening step S5 before the pressing step S6, the solid electrolyte material X1 can be uniformly flattened before being pressed, and a thin and uniform solid electrolyte layer (molded powder) 4 can be formed.

[0050] [Formation of negative electrode layer] Next, after the punch 13 is removed from the inside of the forming dies 11, the nozzle 30 is inserted into the inside of the forming dies 11, and a powdered negative electrode mixture (powder material) X2 is poured above the punch 12, in this case onto the upper surface of the solid electrolyte layer 4. The negative electrode mixture X2 is arranged so as to form an arched shape on the upper surface of the solid electrolyte layer 4. As shown in FIG. 9 , after the negative electrode mixture X2 is poured, the nozzle 30 is moved to a location other than above the forming dies 11, and a powder leveling tool 20 is inserted from an opening above the forming dies 11 and rotated while pressing down the leveling part 21, thereby flattening the arched shape of the negative electrode mixture X2.

[0051] After the negative electrode mixture X2 is flattened and the powder leveling tool 20 is removed, a punch 13 (not shown) is inserted and pressed down, and the negative electrode mixture X2 is compressed by the punches 12 and 13. That is, the above-mentioned steps S3 to S6 are repeated, with the above-mentioned powder material being replaced with the negative electrode mixture X2. This allows the above-mentioned solid electrolyte layer 4 to be formed in the same way as the above-mentioned solid electrolyte layer 4, and the negative electrode layer (powder molded body) 3 laminated on the solid electrolyte layer 4 to be formed thin and uniform.

[0052] [Formation of positive electrode layer] Next, the molding die 10 is turned upside down. That is, as shown in FIG. 10, the punch 13 is placed at the bottom and the punch 12 is placed at the top. Therefore, with the molding die 10 turned upside down, the punch 12 becomes the first punch for flattening the powder material. Thereafter, the upper punch 12 is removed from the inside of the molding die 11. At this time, inside the molding die 10, the negative electrode layer 3 is placed between the punch 13 and the solid electrolyte layer 4 with the upper surface of the solid electrolyte layer 4 exposed.

[0053] Next, the nozzle 30 is inserted into the forming dies 11, and the positive electrode mixture (powder material) X3 is poured above the pestle 13, in this case onto the upper surface of the solid electrolyte layer 4. The positive electrode mixture X3 is arranged so as to form an arched shape on the upper surface of the solid electrolyte layer 4. After the positive electrode mixture X3 has been poured, the nozzle 30 is moved to a location other than above the forming dies 11, and as shown in FIG. 11 , a powder leveling tool 20 is inserted from the opening above the forming dies 11 and pressed down while rotating, thereby flattening the arched shape of the positive electrode mixture X3.

[0054] After the positive electrode mixture X3 is flattened and the powder leveling tool 20 is removed, a punch 12 (not shown) is inserted and pressed, and the positive electrode mixture X3 is compressed by the punch 13 and the punch 12. That is, the above-mentioned steps S3 to S6 are repeated, with the above-mentioned powder material replaced with the positive electrode mixture X3. As a result, a positive electrode layer (powder molded body) 2 laminated on the solid electrolyte layer 4 can be formed, similar to the above-mentioned negative electrode layer 3 and solid electrolyte layer 4.

[0055] Finally, although not shown, the three layers of the positive electrode layer 2, the negative electrode layer 3, and the solid electrolyte layer 4 are further pressurized together. At this time, the three layers are pressurized, for example, at 10 tonf / cm 2 The laminated electrode body 1 is pressed with a load of 0.5g. Thereafter, the pestle 13 is removed from the forming die 11, and the forming die 11 and the pestle 12 are moved relatively to each other, thereby removing the laminated electrode body (powder molding body) 1, in which the positive electrode layer 2, the negative electrode layer 3, and the solid electrolyte layer 4 are stacked, from the molding die 10. In this manner, the laminated electrode body 1 shown in FIG. 1 can be obtained. When removing the laminated electrode body 1 from the molding die 10, the pestle 12 may be removed from the forming die 11, and the forming die 11 and the pestle 13 may be moved relatively to each other. Alternatively, the pestle 13 and the pestle 12 may be moved relatively to the forming die 11 while sandwiching the laminated electrode body 1, thereby removing the laminated electrode body 1 from the inside of the forming die 11, which is preferable because this prevents cracks and chips from occurring in the laminated electrode body 1. Depending on the solid electrolyte material X1, the solid electrolyte may act as a lubricant, making it easier to remove the laminated electrode body 1 from the forming die 11.

[0056] In this way, the method for producing a powder compact makes it possible to form the negative electrode layer 3, the solid electrolyte layer 4, and the positive electrode layer 2, and in turn the laminated electrode body 1, thin and uniformly. As a result, the battery capacity of the all-solid-state battery can be improved, and by forming the solid electrolyte layer 4 uniformly, internal short circuits can be suppressed.

[0057] In the above-described method for manufacturing a powder compact, the solid electrolyte layer 4 is formed first. However, the positive electrode layer 2 may be formed first, followed by the solid electrolyte layer 4, and then the negative electrode layer 3 to form the laminated electrode body 1. Alternatively, the negative electrode layer 3 may be formed first, followed by the solid electrolyte layer 4, and then the positive electrode layer 2 to form the laminated electrode body 1. Also, any one of the negative electrode layer 3, the solid electrolyte layer 4, and the positive electrode layer 2 may be manufactured by the above-described manufacturing method. Furthermore, the powder material does not necessarily need to be arranged in an arched shape, and may be arranged above the pestle 12, the pestle 13, or the powder leveling tool 20 as appropriate.

[0058] [Laminated electrode body (powder molding) manufacturing equipment] Next, a manufacturing apparatus 100 for the laminated electrode body 1 according to an embodiment of the present disclosure will be described with reference to FIG. 3. The manufacturing apparatus 100 for the laminated electrode body 1 has a molding die 10 and a powder leveling tool 20. The molding die 10 has a forming mortar 11, a pestle 12, and a pestle 13. Details of these components have been described above, and therefore a detailed description thereof will be omitted. By manufacturing the laminated electrode body 1 as described above using the manufacturing apparatus 100 for the laminated electrode body 1, that is, by providing the powder leveling tool 20 in addition to the pestle 12 or pestle 13 for compressing the powder material and leveling the powder material with the powder leveling tool 20, the laminated electrode body 1, and in particular the solid electrolyte layer 4, can be formed to be thin and uniform.

[0059] The manufacturing method and manufacturing apparatus for powder molded bodies according to the present disclosure can be used not only for manufacturing the laminated electrode body 1, but also for any powder molded body that can be molded by pressing a powder material, such as a granulated tablet, without any particular limitations.

[0060] Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0061] [Example] As shown in the following Table 1, in the pestles of Examples 1 and 2 and Comparative Examples 1 and 2, powder materials (solid electrolyte material X1, negative electrode mixture X2, and positive electrode mixture X3) were uniformly pressed, and a test was conducted to confirm the quality of the powder molding (laminated electrode body 1).

[0062] [Table 1]

[0063] Example 1 The laminated electrode body 1 was produced using a powder leveling tool 20 having the shape shown in Fig. 12. The load applied when leveling the solid electrolyte material X1, the negative electrode mixture X2, and the positive electrode mixture X3 was 7.2 gf / cm 2 It was decided.

[0064] Example 2 The load when leveling the solid electrolyte material X1, the negative electrode mixture X2, and the positive electrode mixture X3 was 16.2 gf / cm 2 A laminated electrode body 1 was produced in the same manner as in Example 1, except that:

[0065] (Comparative Example 1) A laminated electrode body 1 was produced in the same manner as in Example 2, except that, instead of using the powder leveling tool 20, the upper one of pestles 12 and 13 having the shape shown in FIG. 13 was pressed down while being rotated to level the solid electrolyte material X1, the negative electrode mixture X2, and the positive electrode mixture X3.

[0066] (Comparative Example 2) The load when leveling the solid electrolyte material X1, the negative electrode mixture X2, and the positive electrode mixture X3 was 82.9 gf / cm 2 A laminated electrode body 1 was produced in the same manner as in Comparative Example 1, except that:

[0067] (Evaluation of laminated electrode body) Considering that cracks may occur or the state of each of the laminated electrode bodies 1 in Examples 1 and 2 and Comparative Examples 1 and 2 may change over time, cross-sections of each laminated electrode body 1 were observed using an X-ray CT device ("InspeXio SMX-225CT" manufactured by Shimadzu Corporation) 24 hours after its production. The number of cracks and chips in each of the positive electrode layer 2, solid electrolyte layer 4, and negative electrode layer 3 was checked, and a case where at least one layer satisfied any of the following conditions (1) to (3) was determined to be "defective." (1) If three or more small cracks or chips are found (2) If one or more relatively large cracks or chips are found (3) When peeling is observed between the positive electrode layer 2, the solid electrolyte layer 4, and the negative electrode layer 3 Ten laminated electrode bodies were fabricated for each of Examples 1 and 2 and Comparative Examples 1 and 2 as the laminated electrode bodies 1, and their cross sections were observed to examine the rate of occurrence of defects.

[0068] (Test results) As shown in Table 1, in Examples 1 and 2, in which the powder material was leveled using a powder leveling tool 20 instead of the pestles 12 and 13 for pressure-molding the laminated electrode body 1 and then pressure-molded, the defect rate of the laminated electrode body 1 was low, and since the powder material was pressure-molded in a uniformly leveled state, a more homogeneous laminated electrode body 1 could be obtained. In particular, when the load during flattening was 12 gf / cm 2 In Example 1 described below, the rate of occurrence of defects could be further reduced.

[0069] On the other hand, in Comparative Examples 1 and 2, in which the powder material was flattened using one of the punches 12 and 13, there was no gap between the forming die 11 and the punches 12 and 13, and the powder material was disturbed by the airflow generated when the punches 12 and 13 slid. This prevented the powder material from being uniformly leveled, and it is thought that this resulted in a high rate of defective products. In particular, when the load during flattening was 30 gf / cm 2 In Comparative Example 2, where the load was larger than that in Comparative Example 1, it was more difficult to spread the powder material than in Comparative Example 1, where the load was smaller, and the rate of defectives was higher. [Explanation of symbols]

[0070] 1 laminated electrode body, 2 positive electrode layer, 3 negative electrode layer, 4 solid electrolyte layer, 10 forming die, 11 forming die, 12 punch, 13 punch, 20 powder leveling tool, 21 leveling part, 21a leveling surface, 22 support part, 30 nozzle, X1 solid electrolyte material, X2 negative electrode mixture, X3 positive electrode mixture, d1 inner diameter of forming die, d2 outer diameter of powder leveling tool

Claims

1. A method for producing a powder molded body, comprising: preparing a molding die having a cylindrical molding die and a first punch inserted through a first opening of the molding die, and a powder leveling tool inserted through the first opening of the molding die; a step of introducing a powder material into the forming die through a first opening of the forming die and disposing the powder material inside the forming die; a step of inserting the powder leveling tool from a first opening of the forming dies, and pressing down the powder leveling tool while rotating at least one of the powder leveling tool and the interior of the forming dies in a circumferential direction to flatten the powder material; removing the powder leveling tool from inside the forming dies, and then inserting the first pestle through a first opening of the forming dies to pressurize the flattened powder material.

2. A method for producing the powder molded body according to claim 1, the forming die has a second opening opposite the first opening of the forming die; The molding die further includes a second punch inserted through a second opening of the molding die, before the step of introducing the powder material into the inside of the forming die, a step of inserting the second pestle through a second opening of the forming die and closing the second opening of the forming die; A method for manufacturing a powder molded body, wherein in the step of placing the powder material inside the molding dies, the powder material is placed above the second pestle.

3. A method for producing the powder molded body according to claim 1, A method for manufacturing a powder molded body, wherein the powder material is placed inside the forming dies so as to form an arched shape.

4. A method for producing the powder molded body according to claim 1, In the step of pressing down the powder leveling tool to level the powder material, a gap is formed between the powder leveling tool and the forming dies, When the inner diameter of the forming die is d1, the outer diameter of the powder leveling tool is d2, and the gap is defined as "(d1-d2) / 2", A method for manufacturing a powder molded body, wherein the gap is 0.05 mm or more and 10% or less of the inner diameter d1.

5. A method for producing the powder molded body according to claim 1, In the step of pressing down the powder leveling tool to flatten the powder material, the load applied is 3 gf / cm ２ ~30gf / cm ２ This is a method for producing a powder molded body.

6. A method for producing a powder molded body according to any one of claims 1 to 5, the powder molded body is one of a negative electrode layer, a solid electrolyte layer, and a positive electrode layer of a laminated electrode body to be built in an all-solid-state battery, the powder material is a powder material for forming any one of the negative electrode layer, the solid electrolyte layer, and the positive electrode layer.

7. A method for producing the powder molded body according to claim 6, The method for producing a powder molded body, wherein the molding die has an inner diameter of 5 mm to 50 mm.

8. An apparatus for manufacturing a powder molded body, A molding die and a powder leveling tool are provided. the molding die includes a cylindrical molding die having a first opening, and a first pestle inserted through the first opening of the molding die to pressurize the powder material arranged inside the molding die, The powder leveling tool is inserted from a first opening of the forming dies to level the powder material placed inside the forming dies before pressing.

9. The powder molding manufacturing apparatus according to claim 8, The forming die has a second opening on the opposite side to the first opening, The molding die further includes a second punch inserted through a second opening of the molding die, An apparatus for manufacturing powder molded bodies, wherein the powder material is positioned above the second pestle with the second pestle inserted into the second opening of the molding die.

10. The powder molding manufacturing apparatus according to claim 8, a gap is formed between the powder leveling tool and the forming mortar when the powder leveling tool is inserted into the forming mortar, When the inner diameter of the forming die is d1, the outer diameter of the powder leveling tool is d2, and the gap is defined as "(d1-d2) / 2", The gap is 0.05 mm or more and 10% or less of the inner diameter d1.

11. The powder molding manufacturing apparatus according to any one of claims 8 to 10, the powder molded body is one of a negative electrode layer, a solid electrolyte layer, and a positive electrode layer of a laminated electrode body to be built in an all-solid-state battery, the powder material is a powder material for forming any one of the negative electrode layer, the solid electrolyte layer, and the positive electrode layer.

12. The powder molding manufacturing apparatus according to claim 11, The molding die has an inner diameter of 5 mm to 50 mm, and is a powder molding manufacturing device.

Images