Support for solid electrolyte and method for manufacturing a solid electrolyte support

Abstract

This allows for improved mechanical strength while reducing the thickness of the support structure. [Solution] The support 10 is porous and constitutes the solid electrolyte layer of the all-solid-state battery, as well as supporting the solid electrolyte material. The support 10 is a mesh made of electrically insulating fibers 11. The support 10 has flattened portions 14 formed by heat pressing at the intersections 12 of the fibers 11.

Description

Technical Field

[0001] The present invention relates to a support for solid electrolytes and a method for producing a support for solid electrolytes.

Background Art

[0002] Patent Document 1 discloses an all-solid-state battery. The all-solid-state battery disclosed in Patent Document 1 includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. The solid electrolyte layer includes a solid electrolyte material and a non-woven fabric support that supports the solid electrolyte material.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In all-solid-state batteries, improvement of ionic conductivity in the solid electrolyte layer is required. However, when the thickness of the support is reduced, the mechanical strength of the support decreases, which causes a trade-off that the handling property of the support is impaired.

Means for Solving the Problem

[0005] A support for solid electrolytes for solving the above problems is a porous support that constitutes a solid electrolyte layer of an all-solid-state battery and supports a solid electrolyte material, is in a mesh shape made of electrically insulating fibers, and has a flat portion formed by hot pressing the intersections of the fibers.

[0006] Furthermore, a method for manufacturing a solid electrolyte support to solve the above problems is a method for manufacturing a porous support that constitutes the solid electrolyte layer of an all-solid-state battery and supports the solid electrolyte material, and comprises a heat pressing step of crushing the intersections between electrical insulating fibers by heat pressing a mesh-like material made of electrically insulating fibers.

[0007] According to this configuration or method, the support is mesh-like, thus improving its mechanical strength compared to conventional supports formed from nonwoven fabrics. Furthermore, since flattened sections are formed by heat-pressing the intersections of the fibers, the contact area between the fibers is increased. This increases the frictional force acting on the intersections of the fibers, further improving the mechanical strength of the support.

[0008] Furthermore, because the voids formed by the fibers are uniformly arranged, the variation in ion conductivity depending on the location is reduced. In addition, since the intersections of the fibers have flattened sections formed by heat pressing, the thickness of the support is reduced.

[0009] Therefore, it is possible to improve mechanical strength while reducing the thickness of the support structure. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view of an all-solid-state battery to which a solid electrolyte support according to one embodiment is applied. [Figure 2] Figure 2 is a SEM image of a solid electrolyte support according to one embodiment. [Figure 3] Figure 3 is a plan view of a solid electrolyte support according to one embodiment. [Figure 4] Figure 4 is a plan view of the material according to one embodiment. [Figure 5] Figure 5 is a perspective view of a hot press apparatus for manufacturing a support according to one embodiment. [Modes for carrying out the invention]

[0011] An embodiment of a support for a solid electrolyte and a method for manufacturing the same will be described below with reference to Figures 1 to 5. As shown in Figure 1, the all-solid-state battery comprises a positive electrode layer 91, a negative electrode layer 92, and a solid electrolyte layer 93 provided between the positive electrode layer 91 and the negative electrode layer 92.

[0012] The solid electrolyte layer 93 comprises a solid electrolyte material 94 and a porous solid electrolyte support (hereinafter referred to as support 10) that supports the solid electrolyte material 94. The positive electrode layer 91, the negative electrode layer 92, and the solid electrolyte material 94 have well-known configurations.

[0013] <Support 10> As shown in Figures 2 and 3, the support 10 is a mesh made of electrically insulating fibers 11. In other words, the support 10 is a woven fabric.

[0014] As shown in Figure 3, the support 10 has a flattened portion 14 formed by heat pressing the intersections 12 of the fibers 11. The fiber 11 is made of a thermoplastic resin. Preferably, the fiber 11 is made of a liquid crystal polymer.

[0015] The fiber diameter D of the general portion 13, which is the part of the fiber 11 other than the flattened portion 14, is preferably 10 μm or more and 30 μm or less. More preferably, the fiber diameter D of the general portion 13 is 15 μm or more and 25 μm or less. In this embodiment, the fiber diameter D of the general portion 13 is approximately 20 μm.

[0016] The thickness of the support 10 is preferably 5 μm or more and 25 μm or less. More preferably, the thickness of the support 10 is 15 μm or more and 25 μm or less. In this embodiment, the thickness of the support 10 is approximately 20 μm.

[0017] The support 10 has a large number of voids 15. The voids 15 have a square shape in plan view. It is preferable that the distance L between mutually adjacent fibers 11, that is, the length of one side of the void 15, is 100 µm or more and 500 µm or less. This is because if the distance L is larger than 500 µm, the voids 15 become large, making it difficult to retain the solid electrolyte material 94. Further, if the distance L is smaller than 100 µm, the voids 15 become small, which lowers ionic conductivity. In the present embodiment, the distance L is approximately 125 µm.

[0018] <Method for Manufacturing Support 10> Next, a method for manufacturing the support 10 will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, a raw material 10A of the support 10 is in a mesh shape formed of electrically insulating fibers 11. In the raw material 10A, the entire portion including intersection points 12 of the fibers 11 is constituted by general portions 13.

[0019] The method for manufacturing the support 10 includes a hot pressing step of crushing the intersection points 12 between the fibers 11 by hot pressing the raw material 10A. As shown in FIG. 5, a hot pressing apparatus 20 includes a pair of heat rollers 21. The pair of heat rollers 21 are arranged such that their respective axes are parallel to each other. A heater (not shown) is built in the pair of heat rollers 21. The pair of heat rollers 21 are configured to be rotationally driven in mutually opposite directions.

[0020] In the present embodiment, the raw material 10A is hot pressed by passing the raw material 10A between the pair of heat rollers 21. The heating temperature of the raw material 10A is a temperature lower than the melting point of the resin constituting the fibers 11. Note that before and after hot pressing, the fiber diameter D of the general portions 13 of the fibers 11 hardly changes.

[0021] The support 10 is formed by trimming the hot-pressed raw material 10A into a predetermined shape. <Functions and Effects of the Present Embodiment> (1) Because the support 10 is mesh-like, the mechanical strength of the support 10 is improved compared to conventional supports made from nonwoven fabric. In addition, since flattened portions 14 are provided at the intersections 12 of the fibers 11 which are heat-pressed, the contact area between the fibers 11 is increased. As a result, the frictional force acting on the intersections 12 of the fibers 11 is increased, further improving the mechanical strength of the support 10.

[0022] Furthermore, since the voids 15 formed by the fibers 11 are uniformly arranged, the variation in ion conductivity depending on the location is reduced. In addition, since the intersections 12 of the fibers 11 have flattened portions 14 formed by heat pressing, the thickness of the support 10 is reduced.

[0023] Therefore, it is possible to improve the mechanical strength while reducing the thickness of the support 10. In addition, the ionic conductivity of the solid electrolyte layer 93 is improved, which contributes to improved battery performance.

[0024] (2) Because the fiber 11 is made of liquid crystal polymer, the fiber 11 can withstand greater tension during the spinning process. This makes it possible to reduce the fiber diameter D to 20 μm or less. As a result, the ionic conductivity in the solid electrolyte layer 93 is further improved, which contributes to improved battery performance.

[0025] (3) The method for manufacturing the support 10 includes a step of crushing the intersections 12 of the fibers 11 by heat pressing a mesh-like material 10A made of electrically insulating fibers 11. This method can produce effects similar to those described in (1) above.

[0026] <Variation> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0027] In the above embodiment, the material 10A was heat-pressed using a pair of heat rollers 21, but the material 10A may also be heat-pressed using a pair of heating molds having a flat pressing surface. The fiber diameter D of the general portion 13 of the fiber 11 may be less than 5 μm or greater than 25 μm.

[0028] • The fiber 11 is not limited to being made of a liquid crystal polymer, but may be made of a thermoplastic resin other than a liquid crystal polymer. [Explanation of Symbols]

[0029] 10...Support 11…Fibers 12...Intersection 13…General section 14...Flat part 15...Void 10A...Material 20…Hot press device 21… Heat roller 91...Positive electrode layer 92... Negative electrode layer 93...Solid electrolyte layer 94...Solid electrolyte material

Claims

1. A porous support that constitutes the solid electrolyte layer of an all-solid-state battery and supports the solid electrolyte material, It is a mesh made of electrically insulating fibers, The intersections of the aforementioned fibers are formed by heat pressing, resulting in a flattened portion. Support for solid electrolytes.

2. The aforementioned fiber is made of liquid crystal polymer. Support for solid electrolyte according to claim 1.

3. A method for manufacturing a porous support that constitutes the solid electrolyte layer of an all-solid-state battery and supports the solid electrolyte material, The process includes a heat pressing step in which a mesh-like material made of electrically insulating fibers is heat-pressed to crush the intersections between the fibers. A method for manufacturing a support for a solid electrolyte.

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