Manufacturing method for electrodes for all-solid-state batteries

Abstract

To provide a method for manufacturing electrodes for all-solid-state batteries that can suitably produce electrodes for all-solid-state batteries. [Solution] A method for manufacturing an electrode for an all-solid-state battery according to one aspect of the present disclosure comprises a pressing step, a transfer step, and a peeling step. The pressing step involves forming an active material layer on the front and back surfaces of a current collector and pressing them. The transfer step involves transferring a solid electrolyte layer, which is arranged on a sheet, onto the active material layers formed on both surfaces of the current collector. The peeling step involves peeling the sheet from the solid electrolyte layer.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrode for an all-solid-state battery.

Background Art

[0002] An all-solid-state battery is a secondary battery in which all constituent members are made of solid substances. The all-solid-state battery includes an inorganic solid electrolyte instead of an organic electrolyte and has flame retardancy and low volatility. Further, the all-solid-state battery is manufactured by laminating a plurality of electrodes and a solid electrolyte. Patent Document 1 describes a method for manufacturing an all-solid-state battery in which a laminate including a first current collector is roll-pressed before laminating a second current collector.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The invention described in Patent Document 1 can avoid the situation of roll-pressing a laminate having two different types of current collectors. According to this, it is possible to prevent the generation of shear force during roll-pressing due to the difference in elongation rate between the two types of current collectors and suppress cracking of each layer of the laminate, and it is possible to easily manufacture a high-performance all-solid-state battery. However, the invention described in Patent Document 1 cannot suppress the electrodes from cracking when removing the base material used for laminating each layer.

[0005] In view of the above problems, the present disclosure provides a method for manufacturing an electrode for an all-solid-state battery that can suitably manufacture an electrode for an all-solid-state battery.

Means for Solving the Problems

[0006] A method for manufacturing an electrode for an all-solid-state battery according to one aspect of the present disclosure comprises a pressing step, a transfer step, and a peeling step. The pressing step involves forming an active material layer on the front and back surfaces of a current collector and pressing them together. The transfer step involves transferring a solid electrolyte layer, which is arranged on a sheet, onto the active material layers formed on both surfaces of the current collector. The peeling step involves peeling the sheet from the solid electrolyte layer.

[0007] In the above-described method for manufacturing electrodes for all-solid-state batteries, the pressing pressure in the pressing step may be determined such that the peel strength in the strength evaluation of a single layer of the active material is equal to or greater than the peel strength in the strength evaluation of a single layer of the solid electrolyte layer.

[0008] In the above-described method for manufacturing electrodes for all-solid-state batteries, a roll press is used in the pressing process, and the pressing pressure in the pressing process may be linear pressure.

[0009] In the above-described method for manufacturing electrodes for all-solid-state batteries, the current collector may be a negative electrode current collector, and the active material layer may consist of a negative electrode active material.

[0010] In the above-described method for manufacturing electrodes for all-solid-state batteries, the current collector may be aluminum foil. [Effects of the Invention]

[0011] According to this disclosure, a method for manufacturing electrodes for all-solid-state batteries can be provided, which can suitably produce electrodes for all-solid-state batteries. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of an electrode for an all-solid-state battery according to Embodiment 1. [Figure 2] This is a flow diagram of the manufacturing method for electrodes for all-solid-state batteries according to Embodiment 1. [Figure 3] This is a schematic diagram of the manufacturing method for electrodes for all-solid-state batteries according to Embodiment 2. [Figure 4] This figure shows the various stages of the manufacturing method for electrodes for all-solid-state batteries according to Embodiment 2. [Figure 5]It is an external view of the roll press according to Embodiment 2. [Figure 6] It is an example of the strength evaluation result of a single layer of the active material layer according to Embodiment 2.

Mode for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Also, not all of the configurations described in the embodiments are essential as means for solving the problems. For the sake of clarity of explanation, the following description and drawings have been appropriately omitted and simplified. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations are omitted as necessary.

[0014] <Embodiment 1> Embodiment 1 relates to a method for manufacturing an electrode for an all-solid-state battery. An all-solid-state battery is a secondary battery in which the electrolyte between the positive electrode and the negative electrode is a solid electrolyte, and all the constituent members are solids. An all-solid-state battery can be manufactured by laminating the members of each layer.

[0015] FIG. 1 is a schematic view of an electrode 10 for an all-solid-state battery according to Embodiment 1. The electrode 10 for an all-solid-state battery includes a current collector 101, an active material layer 102, and a solid electrolyte layer 103.

[0016] The current collector 101 is disposed in a state of being sandwiched between two layers of the active material layer 102. The current collector 101 has conductivity and collects and outputs the current generated in the active material layer 102.

[0017] The active material layer 102 is made of an active material. The active material undergoes an oxidation-reduction reaction and converts chemical energy and electrical energy. The active material layer 102 is formed on each of the front and back surfaces of the current collector 101. In the present disclosure, the combination of the current collector 101 and the active material layer 102 is also referred to as an electrode layer.

[0018] The solid electrolyte layer 103 is made of a solid electrolyte. The solid electrolyte is a solid material capable of moving ions in the direction of an electric field. The solid electrolyte layer 103 also functions as a separator that prevents contact between the paired electrode layers. Therefore, by forming the paired electrode layers sandwiching the solid electrolyte layer 103, a set of positive and negative electrodes functions. The solid electrolyte layer 103 is formed on the active material layers 102 formed on both surfaces of the current collector 101. Here, "upper" means the outside in the stacking direction (T-axis direction in FIG. 1) regardless of the direction of gravity. Note that the solid electrolyte is also called SE (Solid Electrolyte).

[0019] FIG. 2 is a flowchart in the manufacturing method of the electrode 10 for an all-solid-state battery according to Embodiment 1. The manufacturing method of the electrode 10 for an all-solid-state battery includes steps S11 to S13.

[0020] In step S11, as a pressing process, the active material layer 102 is formed on each of the front and back surfaces of the current collector 101 and pressed in the stacking direction. According to this, the peel strength of the active material layer 102 is improved. Note that the active material layer 102 is formed on the current collector 101 by, for example, coating.

[0021] In step S12, as a transfer process, the solid electrolyte layer 103 disposed on a sheet (not shown) is transferred onto the active material layers 102 formed on both surfaces of the current collector 101. Specifically, the solid electrolyte layer 103 disposed on the sheet is disposed so as to contact the active material layers 102 formed on both surfaces of the current collector 101 and a load is applied thereto. Thereby, the solid electrolyte layer 103 adheres onto the active material layer 102. Note that the solid electrolyte layer 103 disposed on the sheet is formed on the sheet by, for example, coating. The solid electrolyte layer 103 may be disposed on the sheet after being formed through a sintering process.

[0022] In step S13, as a peeling step, a sheet is peeled off from the solid electrolyte layer 103. As a result, the solid electrolyte layer 103 is placed on the active material layer 102, and the electrode 10 for the all-solid-state battery is formed. By improving the peeling strength of the active material layer 102 in step S11, it is possible to suppress the occurrence of cracks in the active material layer 102 during the peeling step.

[0023] In general methods, the current collector 101 and the active material layer 102 are not pressed in step S11. Therefore, in step S13, if the peel strength of the active material layer 102 is lower than the peel strength of the solid electrolyte layer 103, the active material layer 102 may crack before the sheet peels off from the solid electrolyte layer 103.

[0024] As described above, the method for manufacturing the electrode 10 for an all-solid-state battery, including steps S11 to S13, can suppress cracking within the active material layer 102 during sheet peeling and enable the manufacture of the electrode 10 for an all-solid-state battery. Therefore, the method for manufacturing the electrode 10 for an all-solid-state battery according to this embodiment can suitably manufacture the electrode 10 for an all-solid-state battery.

[0025] Furthermore, the press pressure in the pressing process of step S11 may be determined such that the peel strength in the strength evaluation of the single layer of the active material layer 102 is equal to or greater than the peel strength in the strength evaluation of the single layer of the solid electrolyte layer 103. Specifically, the peel strength in the strength evaluation of the single layer of the solid electrolyte layer 103 is measured in advance. By measuring the relationship between the peel strength in the strength evaluation of the single layer of the active material layer 102 and the press pressure, the press pressure at which the peel strength of the active material layer 102 is equal to or greater than the peel strength of the solid electrolyte layer 103 can be identified.

[0026] By determining the press pressure so that the peel strength of the active material layer 102 is greater than or equal to the peel strength of the solid electrolyte layer 103, the sheet can be peeled from the solid electrolyte layer 103 before cracks occur within the active material layer 102 during sheet peeling. Therefore, the manufacturing method of the electrode 10 for all-solid-state batteries can effectively suppress cracking of the active material layer 102 during sheet peeling.

[0027] <Embodiment 2> Figure 3 is a schematic diagram of the manufacturing method for the electrode 10 for an all-solid-state battery according to Embodiment 2. The electrode 10 for an all-solid-state battery is manufactured using an electrode layer 11 and a separator 12. In the manufacturing method for the electrode 10 for an all-solid-state battery according to Embodiment 2, the electrode 10 is manufactured while conveying the electrode layer 11 and the separator 12 in the X direction, as shown by the arrows in Figure 3. The electrode layer 11 and the separator 12 are processed in scenes A, B, and C, which are enclosed by dashed lines.

[0028] In Figure 3, the electrode layer 11 and the separator 12 are used after being pulled out from their wound state. The dotted line shows the path of the electrode layer 11, the dashed line shows the path of the separator 12, and the solid line shows the path of the sheet 104. Here, since the sheet 104 is included in the separator 12, the solid line and the dashed line share a common path up to scene C.

[0029] Figure 4 shows various scenes of the manufacturing method for the electrode 10 for an all-solid-state battery according to Embodiment 2. Figure 4(a) shows the scene A in Figure 3. Here, scene A corresponds to the pressing process of step S11, which was described with reference to Figure 2. Referring to Figure 3, scene A is the scene before the electrode layer 11 merges with the separator 12.

[0030] In Scene A, the electrode layer 11 has active material layers 102 formed on both its front and back surfaces. The active material layers 102 are formed on the current collector 101 by a coating process. Specifically, the active material layers 102 are formed by coating the active material, which has been dispersed in a solution to form a slurry, onto both the front and back surfaces of the current collector 101 and then drying it. The active material layers 102 may be formed continuously on the current collector 101 in the X direction. In this case, the current collector 101 has a region at its Z-direction end where the active material layers 102 are not formed on both surfaces. The active material layers 102 may also be formed on the current collector 101 at predetermined sizes and spaced apart from each other.

[0031] Here, the current collector 101 is a negative electrode current collector, and the active material layer 102 consists of a negative electrode active material. Therefore, the electrode layer 11, consisting of the current collector 101 and the active material layer 102, is the negative electrode. The current collector 101 is, for example, aluminum foil. The current collector 101 may also be copper foil. The active material layer 102 consists of, for example, a carbon-based material, lithium titanate, or a silicon-based material.

[0032] The electrode layer 11 is pressed in the Y direction by the roll press 20, as shown by the white arrow. This improves the peel strength of the active material layer 102. Furthermore, by using the roll press 20, the occurrence of wrinkles and other defects can be suppressed when the current collector 101 and the active material layer 102 of the electrode layer 11 are stretched by the press pressure. The electrode layer 11 may also be pressed by a vertically driven press machine using flat plates for the upper and lower dies.

[0033] Figure 5 is an external view of the roll press 20 according to Embodiment 2. Figure 5(a) shows the roll press 20 viewed from the X direction. Figure 5(b) shows the roll press 20 viewed from the Z direction. The roll press 20 comprises a first roll 201, a second roll 202, a first frame 203, a second frame 204, a first motor 205, a second motor 206, and a cylinder 207. The first roll 201 is rotatably supported on the first frame 203, and its DS (Drive Side) end is connected to the first motor 205. The second roll 202 is rotatably supported on the second frame 204, and its DS end is connected to the second motor 206.

[0034] The first motor 205 and the second motor 206 rotate in opposite directions to feed the object held between the first roll 201 and the second roll 202 in the X direction. In this case, the first roll 201 and the second roll 202 do not have motors connected to the WS (Work Side), but motors may also be connected to the ends of the WS.

[0035] Cylinder 207 is connected to the second frame 204. Cylinder 207 moves in the Y direction as shown by the white arrow, pressing the second roll 202, along with the second frame 204, against the first roll 201. In this way, the roll press 20 can apply press pressure to the material sandwiched between the first roll 201 and the second roll 202. Here, the press pressure is linear pressure. Note that the cylinder may be provided on the first frame 203 side, or on both the first frame 203 side and the second frame 204 side.

[0036] Referring again to Figure 4, Figure 4(b) shows the scene B in Figure 3. Here, scene B corresponds to the transfer process of step S12, which was explained with reference to Figure 2. Referring to Figure 3, scene B is the scene after the electrode layer 11 and the separator 12 have merged, but before the sheet 104 is peeled off.

[0037] In Scene B, the electrode layer 11 has separators 12 on both its front and back surfaces. The separator 12 consists of a solid electrolyte layer 103 and a sheet 104. The separator 12 is positioned with the side containing the solid electrolyte layer 103 facing the electrode layer 11. The solid electrolyte layer 103 of the separator 12 is placed on the sheet 104 and is positioned to be in contact with the active material layer 102 of the electrode layer 11.

[0038] Here, the solid electrolyte layer 103 placed on the sheet 104 is formed on the sheet 104, for example, by coating the surface of the sheet 104 with an electrolyte composition dispersed in a solution to form a slurry and then drying it. The solid electrolyte layer 103 may also be formed by a sintering process and then placed on the sheet 104. The solid electrolyte layer 103 can be made of oxides, sulfides, halides, etc. The solid electrolyte layer 103 may also be made of polymers.

[0039] The roll press 30 clamps the separators 12, which are arranged on both sides of the electrode layer 11, in the Y direction and presses them in the Y direction as shown by the white arrow. As a result, the solid electrolyte layer 103 is transferred onto the active material layer 102, and the electrode 10 for the all-solid-state battery is formed. Note that the roll press 30 has the same structure as the roll press 20 described with reference to Figure 5, so a redundant explanation will be omitted.

[0040] Figure 4(c) shows the scene C in Figure 3. Here, scene C corresponds to the peeling process of step S13, which was explained with reference to Figure 2. Referring to Figure 3, scene C is the scene in which the sheet 104 is peeled off from the electrode 10 for the all-solid-state battery.

[0041] In scene C, sheet 104 is peeled off from the solid electrolyte layer 103 transferred onto the active material layer 102. This produces an all-solid-state battery electrode 10 comprising a current collector 101, an active material layer 102, and a solid electrolyte layer 103. Referring again to Figure 3, the produced all-solid-state battery electrode 10 and the peeled sheet 104 are wound up and recovered, respectively.

[0042] The relationship between the peel strength in the single-layer strength evaluation of the active material layer 102 and the press pressure, as well as the peel strength in the single-layer strength evaluation of the solid electrolyte layer 103, are measured in advance. Based on the measurement results, the press pressure in scenario A is determined such that the peel strength in the single-layer strength evaluation of the active material layer 102 is greater than or equal to the peel strength in the single-layer strength evaluation of the solid electrolyte layer 103.

[0043] Figure 6 shows an example of the strength evaluation results for a single layer of the active material layer 102 according to Embodiment 2. Figure 6 shows the peel strength (N / cm²) on the vertical axis. 2 The horizontal axis shows the press line pressure (t / cm). As shown in Figure 6, the peel strength of the single layer of the active material layer 102 in the unpressed state is 7.1 (N / cm). 2 ) was the case. In the unpressed state, the press line pressure was 0 (N / cm). 2 This refers to the state of ). Here, the peel strength of the solid electrolyte layer 103 as measured in advance is 12.1 (N / cm²), as shown by the dotted line in Figure 6.2 ) was.

[0044] The values ​​N1(t / cm), N2(t / cm), and N3(t / cm) shown in Figure 6 represent the press pressures when the active material layer 102 was pressed by gradually increasing the press pressure. When the peel strength of the single layer of the active material layer 102 was measured after pressing at each press pressure, the peel strength increased as the press pressure increased. In Figure 6, the peel strength of the single layer of the active material layer 102 was 12.1(N / cm) when the press pressure was N1(t / cm). 2 ) exceeds this value. In this case, the press pressure in scenario A is set to N1 (t / cm) or higher.

[0045] According to this, in scenario A, the current collector 101 and the active material layer 102 are pressed together, which preferably increases the peel strength of the active material layer 102. Therefore, in scenario C, when the sheet 104 is peeled off, cracking of the active material layer 102 is suppressed, and the sheet 104 can be preferably peeled off from the solid electrolyte layer 103.

[0046] As described above, the manufacturing method for the electrode 10 for all-solid-state batteries according to this embodiment can suppress cracking of the active material layer 102 when the sheet 104 is peeled off. Therefore, the manufacturing method for the electrode 10 for all-solid-state batteries according to this embodiment can suitably manufacture the electrode 10 for all-solid-state batteries.

[0047] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the electrode layer may be manufactured elsewhere. Also, the pressing process may be carried out on a separate line from the transfer process and the peeling process. Furthermore, the electrodes for the all-solid-state battery may not be wound up and recovered, but may be cut to a predetermined size after the peeling process. [Explanation of Symbols]

[0048] 10 Electrodes for all-solid-state batteries 11 Electrode layer 12 Separators 20, 30 Roll Press 101 Current collector 102 Active material layer 103 Solid electrolyte layer 104 seats 201 Roll 1 202 Roll 2 203 Frame 1 204 Frame 2 205 First Motor 206 Second Motor 207 Cylinder A, B, C scene

Claims

1. A pressing process in which an active material layer is formed on both the front and back surfaces of the current collector and then pressed, A transfer step of transferring a solid electrolyte layer, which is arranged on a sheet, onto the active material layer formed on both sides of the current collector, A peeling step of peeling the sheet from the solid electrolyte layer, A method for manufacturing electrodes for all-solid-state batteries, comprising the features described above.

2. The method for manufacturing an electrode for an all-solid-state battery according to claim 1, wherein the pressing pressure in the pressing step is determined such that the peel strength in the strength evaluation of a single layer of the active material layer is equal to or greater than the peel strength in the strength evaluation of a single layer of the solid electrolyte layer.

3. The method for manufacturing an electrode for an all-solid-state battery according to claim 1 or 2, wherein a roll press is used in the pressing step, and the pressing pressure in the pressing step is linear pressure.

4. The method for manufacturing an electrode for an all-solid-state battery according to claim 1 or 2, wherein the current collector is a negative electrode current collector and the active material layer consists of a negative electrode active material.

5. The method for manufacturing an electrode for an all-solid-state battery according to claim 4, wherein the current collector is aluminum foil.

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