Pressurizing device, pressurizing method

Abstract

To provide a pressing apparatus and a pressing method capable of lowering interfacial resistance between solid electrolyte layers and electrodes with a simple configuration.SOLUTION: A pressing apparatus 1 presses a laminate 3 including electrodes (a positive current collecting electrode 31 and a negative current collecting electrode 33) and solid electrolyte layers 32, and includes compression means (a roll pressing machine 2) that compresses the laminate 3. The compression means 2 compresses the laminate 3 with buffer members 4 interposed having recesses or projections on surfaces adjacent to the laminate 3. In one embodiment, the compression means 2 compresses the laminate having the negative electrode (the negative current collecting electrode 33) containing lithium. Further, in one embodiment, the compression means 2 is a roll pressing machine 2.SELECTED DRAWING: Figure 3

Description

Technical Field

[0004]

[0001] The present invention relates to a pressing device and a pressing method.

Background Art

[0002] In recent years, in the manufacturing process of all-solid-state batteries, a manufacturing method has been proposed in which a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer are efficiently adhered by roll pressing. When performing roll pressing, in order to appropriately set the pressing strength on a sheet-like object and to make the pressing uniform in the in-plane direction, a technique has been proposed in which a buffer film is inserted on the contact surface of the object with the roll (see, for example, Patent Document 1). Further, in a roll process in which a roll protection film is applied to the active material layer and the current collector, the active material layer, and the roll protection film are combined and roll pressed, a technique has been proposed to prevent damage to the roll in the roll pressing process by applying a roll protection film with as few irregularities as possible (see, for example, Patent Document 2). On the other hand, a technique has been proposed in which fine irregularities are provided on the surface of the roll in the first stage of three-stage roll pressing to improve the filling density of the active material into the foamed porous metal substrate (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0005] In view of the above-mentioned circumstances, the present invention aims to provide a pressurizing device and pressurizing method that can reduce the interfacial resistance between the solid electrolyte layer and the electrode with a simple configuration. Ultimately, the aim is to realize a technology for manufacturing high-performance batteries that can be repeatedly rapidly charged and discharged. [Means for solving the problem]

[0006] (1) A pressurizing device (e.g., pressurizing device 1 described later) for pressurizing a laminate (e.g., laminate 3 described later) comprising electrodes (e.g., positive electrode current collector 31, negative electrode current collector 33, described later) and a solid electrolyte (e.g., solid electrolyte layer 32, described later), wherein the pressurizing device comprises a compression means (e.g., roll press machine 2, described later) for compressing the laminate, and the compression means compresses the laminate by interposing a buffer member (e.g., buffer member 4, described later) having a recess or protrusion on a surface adjacent to the laminate.

[0007] (2) The compression means is the pressurizing device of (1) above, which compresses the laminate having a lithium-containing negative electrode (for example, a negative electrode current collector electrode 33 described later).

[0008] (3) The compression means is a roll press machine (for example, roll press machine 2 described later), the pressurizing device of (1) or (2) above.

[0009] (4) A pressurizing method for pressurizing a laminate (e.g., laminate 3 described later) including electrodes (e.g., positive electrode current collector 31, negative electrode current collector 33 described later) and a solid electrolyte (e.g., solid electrolyte layer 32 described later) using a pressurizing device (e.g., pressurizing device 1 described later), the pressurizing method comprising: a laminate transport step (e.g., laminate transport step S1 described later) in which the laminate is transported accompanied by a buffer member whose surface facing the laminate has a recess or a convex portion; and a compression step (e.g., compression step S2 described later) in which the laminate transported in the laminate transport step is compressed with the buffer member interposed therebetween.

[0010] (5) The pressurizing method of (4) above, wherein the compression step compresses the laminate having a lithium-containing negative electrode.

[0011] (6) The compression step is the pressurizing method of (4) or (5) above, wherein the laminate is compressed by a roll press. [Effects of the Invention]

[0012] The pressurizing device of (1) is a pressurizing device for pressurizing a laminate containing electrodes and a solid electrolyte, and comprises a compression means for compressing the laminate, wherein the compression means compresses the laminate by interposing a buffer member having recesses or protrusions on a surface adjacent to the laminate. As a result, when the compression means compresses the laminate, the compressive force in the in-plane direction is made uniform, and the recesses or protrusions of the buffer member are uniformly transferred to the electrodes over the entire surface. As a result of the increased contact area at the interface between the electrodes and the solid electrolyte where the recesses or protrusions are formed, the interface becomes tightly bonded and the bonding properties are good, making it possible to manufacture secondary battery components with low DCR resistance and high charge / discharge efficiency.

[0013] In the pressurizing device of (2), the compression means compresses the laminate having a lithium-containing negative electrode. This makes it possible to obtain lithium-ion battery components with low DCR resistance and high charge / discharge efficiency.

[0014] In the pressurizing device of (3), the compression means is a roll press machine. This allows the laminate to be compressed with high efficiency.

[0015] (4) The pressing method is a pressing method for pressing a laminate including an electrode and a solid electrolyte, including a laminate conveying step of conveying the laminate with a buffer member whose opposing surface to the laminate has a concave or convex portion, and a compression step of compressing the laminate conveyed in the laminate conveying step with the buffer member interposed therebetween. Therefore, when the laminate is compressed in the compression step, the compressive force in the in-plane direction is made uniform, and the concave or convex portion of the buffer member is transferred to the electrode uniformly over the entire surface. As a result, the contact area of the interface between the electrode and the solid electrolyte formed with the concave or convex portion increases, so that they are closely adhered and the bonding property becomes good, and elements of a secondary battery with low DCR resistance and high charge / discharge efficiency can be manufactured.

[0016] (5) In the pressing method of (5), in the compression step, a laminate having a negative electrode containing lithium is compressed. Thereby, elements of a lithium-ion battery with low DCR resistance and high charge / discharge efficiency can be manufactured.

[0017] (6) In the pressing method of (6), in the compression step, the laminate is compressed by a roll press. Thereby, the laminate can be compressed with high efficiency.

Brief Description of the Drawings

[0018] [Figure 1] It is a conceptual diagram showing a compression means of a pressing device which is an embodiment of the present invention. [Figure 2] It is a perspective view of the compression means of FIG. 1. [Figure 3] It is a conceptual diagram showing a laminate compressed by the compression means of FIG. 1 together with a buffer member. [Figure 4] It is a diagram showing the surface property of the buffer member in FIG. 3. [Figure 5] It is a diagram showing the interface between an electrode and a solid electrolyte compressed by the compression means of FIG. 1. [Figure 6] It is a diagram explaining the superiority of an all-solid-state battery due to the application of a buffer member during roll pressing. [Figure 7]This is a diagram for explaining and comparing the effects when a buffer member is applied and not applied during roll pressing. [Figure 8] This is a process diagram showing the pressing method which is an embodiment of the present invention.

Embodiments for Carrying out the Invention

[0019] FIG. 1 is a conceptual diagram showing a roll press 2 as a compression means of a pressing device 1 which is an embodiment of the present invention. The roll press 2 has a pair of metal pressing rolls 2a and 2b. FIG. 2 is a perspective view of the pressing rolls 2a and 2b. The pair of pressing rolls 2a and 2b rotate along the conveyance direction of the laminate 3 (the direction of the arrow in FIG. 1) by a rotation mechanism not shown, and compress the laminate 3 while sandwiching it therebetween. Specifically, the roll press 2 compresses the laminate 3 being conveyed by the pair of pressing rolls 2a and 2b with a buffer member 4 interposed therebetween, the facing surface of which to the laminate 3 is a surface having a concave portion or a convex portion. The buffer member 4 is sent out from a feeder 5, and is conveyed together with the laminate 3 so that the surface having the concave portion or the convex portion faces the laminate 3 and follows the laminate 3 being conveyed.

[0020] FIG. 3 is a conceptual diagram showing the laminate 3 compressed by the roll press 2 together with the buffer member. The laminate 3 is formed by laminating negative electrode current collecting electrodes 33 via solid electrolyte layers 32 on one surface and the other surface of a positive electrode current collecting electrode 31, respectively. The positive electrode current collecting electrode 31 is an electrode formed by coating both surfaces of a single positive electrode sheet-like current collector which is a current collecting foil such as aluminum with a positive electrode mixture containing a positive electrode active material such as lithium cobaltate or lithium phosphate, and further containing a conductive auxiliary agent, a binder, and the like. The negative electrode current collecting electrode 33 is an electrode formed by coating a surface of a single negative electrode sheet-like current collector which is a current collecting foil of copper with a negative electrode mixture containing a negative electrode active material such as graphite or lithium titanate, and further containing a binder and the like. On both surfaces of the laminate 3, buffer members 4 are arranged such that the surfaces having the concave portions or the convex portions correspond.

[0021] Figure 4 shows a plan view of the cushioning member 4, specifically the surface facing the laminate 3. In Figure 4, a magnified view of surface portion A shows the surface properties. This facing surface is a surface with concave or convex portions, but in this example, it is a rough surface formed so that the irregularities are uniformly distributed in the surface direction. The cushioning member 4 has a Young's modulus smaller than the pair of metal pressure rolls 2a and 2b of the roll press machine 2. Therefore, macroscopically, the cushioning member 4 absorbs the deflection of the pressure rolls 2a and 2b when the laminate 3 is compressed, and compresses the laminate 3 uniformly across its entire surface. On the other hand, microscopically, the cushioning member 4 transfers the irregularities of its rough surface to the negative electrode current collector 33 of the laminate 3.

[0022] Figure 5 shows the interface between the negative electrode current collector 33 and the solid electrolyte layer 32, where the irregularities on the rough surface of the buffer member 4 have been transferred. In Figure 5, the negative electrode current collector 33 is labeled "negative electrode," and the solid electrolyte layer 32 is labeled "SE layer." The areas indicated by the long arrows have relatively fine irregularities, and the contact area between the "negative electrode" and the "SE layer" per unit area when viewed in the direction of the arrows is large. That is, the DCR resistance at the interface between the negative electrode current collector 33 and the solid electrolyte layer 32 is low. For this reason, the negative electrode current collector 33 and the solid electrolyte layer 32 can be evaluated as elements of a secondary battery (all-solid-state battery) with high charge-discharge efficiency.

[0023] Figure 6 illustrates the advantages of the all-solid-state battery when the buffer material 4 is applied during roll pressing. In Figure 6, the case where the buffer material 4 is applied during roll pressing is indicated as "with," and the case where the buffer material 4 is not applied during roll pressing is indicated as "without." As can be easily seen from Figure 6, applying the buffer material 4 during roll pressing provides outstanding advantages in both DCR resistance and charge / discharge efficiency.

[0024] Figure 7 illustrates the effects of applying and not applying the buffer member 4 during roll pressing by the roll press machine 2. In Figure 7, the copper current collector foil of the negative electrode current collector 33 is denoted as "Cu," and the negative electrode active material such as lithium titanate is denoted as "Li." When the buffer member 4 was applied during roll pressing, the irregularities of the rough surface of the buffer member 4 were transferred to the negative electrode active material of the negative electrode current collector 33, but no processing marks were observed. On the other hand, When cushioning material 4 was not applied during roll pressing, naturally, there was no transfer of unevenness, and processing marks were observed.

[0025] Figure 8 is a process diagram showing a pressurization method according to an embodiment of the present invention. The pressurization method using the pressurization device 1 includes the following two steps: a laminate transport step S1 in which the laminate 3 is transported with a buffer member 4 whose opposing surface has a concave or convex portion, and a compression step S2 in which the laminate 3 transported in the laminate transport step S1 is compressed with the buffer member 4 interposed between them.

[0026] The pressurizing device and pressurizing method of this embodiment provide the following effects.

[0027] The pressurizing device 1 of (1) is a pressurizing device 1 that pressurizes a laminate 3 including a positive electrode current collector 31, a negative electrode current collector 33, and a solid electrolyte layer 32, and includes a roll press machine 2 which is a compression means for compressing the laminate 3, and the roll press machine 2 compresses the laminate 3 by interposing a buffer member 4 having recesses or protrusions on the surface adjacent to the laminate 3. As a result, when the roll press machine 2 compresses the laminate 3, the compressive force in the in-plane direction is made uniform, and the recesses or protrusions of the buffer member 4 are transferred uniformly and evenly to the negative electrode current collector 33. As a result of the increased contact area at the interface between the negative electrode current collector 33 and the solid electrolyte layer 32 in which the recesses or protrusions are formed, the interface becomes tightly attached and the bonding properties are good, making it possible to manufacture secondary battery elements with low DCR resistance and high charge / discharge efficiency.

[0028] The pressurizing device 1 in (2) compresses the negative electrode current collector electrode 33, which is an electrode formed by coating the surface of a single negative electrode sheet-shaped current collector, which is a copper current collector foil, with a negative electrode mixture containing a binder and other materials, such as graphite or lithium titanate. As a result, the contact area of ​​the interface between the negative electrode current collector electrode 33 and the solid electrolyte layer 32 increases, resulting in tighter adhesion and good bonding properties, making it possible to obtain a secondary battery element with low DCR resistance and high charge / discharge efficiency.

[0029] In the pressurizing device of (3), the compression means is the roll press machine 2. This allows the laminate to be compressed with high efficiency.

[0030] The pressurizing method of (4) is a pressurizing method for pressurizing a laminate 3 including a positive electrode current collector 31, a negative electrode current collector 33, and a solid electrolyte layer 32, and includes a laminate transport step S1 in which the laminate 3 is transported accompanied by a buffer member 4 whose surface facing the laminate 3 has a recess or a protrusion, and a compression step S2 in which the laminate 3 transported in the laminate transport step S1 is compressed with the buffer member 4 interposed. As a result, when the laminate 3 is compressed in the compression step S2, the compressive force in the in-plane direction is made uniform, and the recess or protrusion of the buffer member 4 is transferred uniformly to the electrodes over the entire surface. As a result of the increased contact area at the interface between the negative electrode current collector 33 and the solid electrolyte layer 32 in which the recess or protrusion is formed, the interface becomes tightly attached and the bonding properties are good, making it possible to manufacture a secondary battery (all-solid-state battery) element with low DCR resistance and high charge / discharge efficiency.

[0031] In the pressurization method of (5), the laminate having a lithium-containing negative electrode is compressed in the compression step S2. This makes it possible to manufacture lithium-ion battery components with low DCR resistance and high charge / discharge efficiency.

[0032] In the pressurization method of (6), the laminate 3 is compressed by a roll press in the compression step S2. This allows the laminate 3 to be compressed with high efficiency.

[0033] While embodiments of the present invention have been described above, the present invention is not limited thereto. Modifications may be made as appropriate within the scope of the spirit of the present invention. For example, when compressing a laminate, a plate press may be used instead of a roll press. [Explanation of Symbols]

[0034] 1… Pressurizing device 2… Roll press machine 2a, 2b... Pressure roll 3…Laminate 4…Cushioning material 5…Supplier 31…Positive electrode current collector 32...Solid electrolyte layer 33... Negative electrode current collector S1...Laminate conveying process S2…Compression process

Claims

1. A pressurizing device for pressurizing a laminate containing electrodes and a solid electrolyte, The laminate is provided with a compression means for compressing the laminate, The compression means compresses the laminate by interposing a buffer member, the buffer member having a surface facing the laminate in which recesses and protrusions are uniformly distributed in the surface direction. Pressurizing device.

2. The pressurizing device according to claim 1, wherein the compression means compresses the laminate having a lithium-containing negative electrode.

3. The pressurizing device according to claim 1 or 2, wherein the compression means is a roll press machine.

4. A pressurizing method for pressurizing a laminate containing electrodes and a solid electrolyte using a pressurizing device, The pressurizing device comprises a compression means for compressing the laminate, The compression means compresses the laminate by interposing a buffer member, the buffer member having a surface facing the laminate in which recesses and protrusions are uniformly distributed in the surface direction. A laminate conveying step in which the laminate is conveyed with a buffer member whose opposing surface has a recess or a protrusion, A compression step in which the laminate conveyed in the laminate conveying step is compressed with the buffer member interposed, A pressurizing method including the following.

5. The pressurizing device according to claim 4, wherein the compression step compresses the laminate having a lithium-containing negative electrode.

6. The pressurizing method according to claim 4 or 5, wherein the compression step involves compressing the laminate by a roll press.

Images