JPS63244569A - Manufacture of electrochemical element - Google Patents

Abstract

PURPOSE:To make electrical, ionic bonding good by depositing a conductor on the part, where is to be in contact with an electrode material, of a solid electrolyte, then connecting the electrode material there. CONSTITUTION:Solid electrolyte particles and a binder are mixed and the mixture is molded to form a molding, then a conductor is deposited on the molding. An electrode material is connected to the molding. Thereby, the bonding of the conductor to the electrolyte molding is kept good against deformation of the molding caused by the force applied from the outside and the electrical, ionic bonding between them is also kept good. For example, if the solid electrolyte is a copper ion conductive solid electrolyte indicated in RbCu4I2-xCl3+x (x=0.25-1.0) and the electrode material is metallic copper, metallic copper is used as the conductive material. Thereby, the solid electrolyte molding and the electrode material are effectively bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a solid-state electrochemical device whose constituent materials are all solid substances. More specifically, the present invention relates to a method of bonding an electrode material to a flexible solid electrolyte molded body containing a binder such as synthetic rubber and a solid electrolyte.

Solid-state electrochemical devices, in which all conventional technical components are solid materials,
Compared to devices using liquid electrolytes that require a certain size,
There is no need to worry about liquid leakage or gas generation. In addition, since a container of a certain size is not necessary, the shape can be chosen arbitrarily, and small,
It has many advantages over conventional devices, such as being extremely easy to make it thin and being able to be housed in the same package as other electronic components.

In the present invention, the solid electrochemical device refers to a solid device that utilizes electrochemical reactions, such as a solid electrolyte battery, a solid electric double layer capacitor, and a solid electrochromic display device.

However, since all of the components are solid, solid-state electrochemical devices have the disadvantage that they are extremely brittle and easily damaged by mechanical shock, and the bond between the components, especially the bond between the solid electrolyte and the electrode material, is easily damaged. have

In order to eliminate this drawback, the present inventors have proposed a method of mixing a binder with a solid electrolyte. By using a flexible solid electrolyte molded body made of a binder such as fluororesin rubber and a solid electrolyte as one of the constituent elements, the solid electrolyte and electrode material are resistant to mechanical shock. The purpose is to make the bond less likely to be damaged.

Problems to be Solved by the Invention In order to impart sufficient flexibility, the greater the amount of binder mixed, the better.
Although the mechanical bond between the components improves and becomes less likely to peel off, the electrical and ionic bond deteriorates, and the voltage of the device as a whole decreases as soon as the output current becomes small or the polarization becomes large. There is a problem with doing so.

In order to alleviate the above problems, the present invention provides a method for joining an electrode material to a solid electrolyte molded body containing a binder and a solid electrolyte.

Means for Solving the Problems In the present invention, after a conductor is deposited on the portion of the solid electrolyte molded body that comes into contact with the electrode material, the solid electrolyte molded body and the electrode material are joined. For example, if the solid electrolyte is RbCu
+Iz-xce! l+X (X=0.25~1.0)
When the electrode material is metal steel, the solid electrolyte molded body and the electrode material are effectively bonded by using metal steel as the conductor material.

Function According to the present invention, the conductor deposited on the surface of the solid electrolyte molded body maintains good electrical and ionic bonding with the inside of the solid electrolyte molded body even when deformed by external forces of the solid electrolyte molded body. be able to. Therefore, by bonding the electrode material to this surface, the solid electrolyte molded body and the electrode material are bonded with good electrical and ionic bonding maintained.

Example Specific examples will be described below.

(Example 1) Steel ion conductive solid electrolyte obtained by heating a mixture of RbCe, Cu I, and CuCe in a predetermined ratio at 200°C for 17 hours in a sealed container, and then further heating at 130°C for 17 hours. , Rb Cu4 I 1. 100 parts by weight of a toluene solution containing 15% by weight of styrene-butadiene rubber (JSR-1500 manufactured by Japan Synthetic Rubber Co., Ltd., hereinafter referred to as SBR) was added to 100 parts by weight of δc(ls,s powder), and the mixture was heated in an alumina ball mill for 24 hours. A slurry was obtained by uniformly stirring and mixing.

This slurry is spread on a Teflon substrate with a doctor blade so that the thickness after dissipating the toluene is approximately 70 μm. After dissipating the toluene, the slurry is peeled off from the Teflon substrate to form a solid electrolyte with a thickness of approximately 70 μm. I got a body.

On the other hand, as an electrode material, purity 99.99%, thickness 0.2+
ll1l, a copper plate with a surface smoothness of ±0.5 μm and a diameter of 9.
A disk of 8 m in length was punched out and subjected to reduction treatment at 300° C. for 3 hours in a hydrogen furnace. Copper was placed on the previously prepared solid electrolyte molded body at a vacuum level of 2×IO-5 Torr.

Approximately 0゜04μ by resistance heating evaporation method with evaporation temperature of 950℃
A solid electrolyte molded body (a) was obtained, which was formed into an island shape with a thickness of m and had copper deposited on its surface. The solid electrolyte molded body thus obtained was punched out into a disk shape with a diameter of 10 wm.

Place the copper disks prepared earlier above and below this disk and make 20b.
The copper disk and the solid electrolyte molded disk were joined at a pressure of /-. This is called cell A.

Next, a diameter of 10 mm without copper vapor deposited on the surface of the solid electrolyte molded body was
Cell B was obtained by joining copper disks in the same manner except that the disk of the solid electrolyte molded body (b) of Il111 was used.

In addition, only the previously synthesized solid electrolyte was made to a thickness of about 70 am,
Solid electrolyte molded body (C) obtained by pressure molding at a pressure of 200 kg/cd into a disc shape with a diameter of 10+ m
Cell C was obtained by joining a copper disk to the disk in the same manner as Cell A.

Electrical and ionic connectivity test With an amplitude of 75 mV centered on Ov, the frequency is 0,067
By applying a symmetrical triangular wave DC voltage of Hz between the upper and lower copper plates of Cell A, Cell B, and Cell C, and measuring the magnitude of the current flowing in each cell, electrical and ionic bonding is established. We evaluated the degree of

At this time, at the joint part between the copper disk and the solid electrolyte molded body, where a positive voltage is applied to the other copper disk of the upper and lower copper disks, the solid electrolyte molded body is moved from the copper disk to the solid electrolyte molded body. Copper ions (Cu”) are dissolved into the solid electrolyte molded body, and at the joint between the other copper disk and the solid electrolyte molded body, the Cu in the solid electrolyte molded body is dissolved.
A precipitation reaction of + onto the copper disk occurs. The current accompanying the electrochemical reaction of dissolving and depositing Cu is measured as a current flowing in each cell.

Figure 1 is a graph of the current values obtained in this manner at 20°C for Cells A, B, and C, with the horizontal axis representing the voltage applied to the upper and lower copper disks, and the vertical axis representing the current value. It is shown as follows.

In accordance with the present invention, cell A obtained by bonding a solid electrolyte molded body with copper vapor-deposited rear body disk has almost the same level of performance as cell C using a solid electrolyte molded body containing no binder. Although a large current is applied, in cell B obtained by joining a copper disk to a solid electrolyte molded body on which no steel is vapor-deposited, almost no current flows due to the dissolution and precipitation of copper. Regarding the curve showing the relationship between voltage and current for cell B in Figure 1, the fact that the current does not change between -50 mV and +50 mV indicates that no dissolution or precipitation of copper occurs here. .

Peeling test: Cut into 50 mm square pieces and reduced in a hydrogen furnace with a thickness of 0.
A sample was prepared by thermo-compression bonding the previously produced solid electrolyte molded body with a size of 40 square meters on which copper was not vapor-deposited, at a pressure of 20 kg/co (at a pressure of 20 kg/co) at 130°C for 1 minute, on a copper plate of 2 layers. When a 5-nun substrate test was performed, no peeling occurred.

Next, when a peel test was conducted under the same conditions on the solid electrolyte molded body on which copper was vapor-deposited, no peeling occurred at all.

(Example 2) A solid electrolyte was prepared in the same manner as in Example 1, except that RbCu41t, 5ce3.5 was used as the solid electrolyte, and acrylonitrile butadiene rubber (hereinafter referred to as NBR) manufactured by Nippon Synthetic Rubber was used as the binder. A molded body (e) was produced. Metal steel was added to this solid electrolyte molded body in the same manner as in Example 1.
．． A solid electrolyte molded body (d) having a thickness of 0.02 μm and having copper deposited on its surface by resistive heating vapor deposition in the form of islands was obtained.

These solid electrolyte molded bodies and only the solid electrolyte that does not contain NBR have a thickness of about 100 μm = 200 kg /
Cell D (
cell using a solid electrolyte molded body with copper vapor-deposited on its surface),
Cell E (a cell using a solid electrolyte molded body with no copper deposited on its surface) and Cell F (a cell using a solid electrolyte not containing NBR) were constructed.

The same electrical and ionic bonding tests as in Example 1 were conducted. The results are shown in Figure 2.

Further, when a peeling test similar to that in Example 1 was conducted, there was no peeling at all in both the solid electrolyte molded body with copper vapor-deposited on the surface and the solid electrolyte molded body without copper vapor-deposited on the surface.

(Example 3) A synthetic rubber consisting of a 50:50 (parts by weight) mixture of Rb Cu41t, 5ces, s as a solid electrolyte, 5BR1 used in Example 1 as a binder, and NBR used in Example 2 as a binder was used as a solid electrolyte. A solid electrolyte molded body ()l) having a thickness of approximately 150 μm was produced in the same manner as in Example 1, except that the following was used. Further, in the same manner as in Example 1, a solid electrolyte molded body (g) was obtained in which copper was deposited on the surface to a thickness of 0.05 μm by resistance heating vapor deposition.

In addition, 200 kg/c! of solid electrolyte molded body (i) with a thickness of approximately 150 μm consisting only of solid electrolyte! It was obtained by pressure molding at a pressure of .

In the same manner as in Examples 1 and 2, Cell G (a cell using a solid electrolyte molded body with steel deposited on its surface), Cell H (a cell using a solid electrolyte molded body without steel deposited on its surface), Cell I (a cell using a molded body containing only a solid electrolyte) was constructed.

The same electrical and ionic bonding tests as in Example 1.2 were conducted. The results are shown in Figure 3.

In addition, when a peel test similar to Examples 1 and 2 was conducted,
Both the solid electrolyte molded body with copper vapor-deposited on its surface and the solid electrolyte molded body without steel vapor-deposited on its surface (no peeling occurred).

(Example 4) Solid electrolyte molded bodies (c), (f), (i) which did not contain a binder and which were made in Examples 1 to 3, and which contained a binder but had metal steel deposited on the surface. Solid electrolyte molded bodies (b), (e), (h) which are not made of solid electrolyte, and solid electrolyte molded bodies (a), (d), (h) which contain a binder and have metal steel deposited on the surface according to the present invention. Regarding g), solid electrolyte batteries were assembled by the method shown below using disk-shaped samples each having a diameter of 10+ nm.

Positive electrode: 50 parts by weight of CugMOeSa and solid electrolyte, R
b Cut 1 +, gsCe s, vs 50 parts by weight,
Toluene solution containing 20 weight percent SBR 10
An electrode slurry obtained by mixing 0 parts by weight in an alumina ball mill for 24 hours was coated on stainless steel foil to a thickness of approximately 200 mm.
An electrode sheet with a diameter of 10 wm was obtained and punched out to form a positive electrode.

Negative electrode: copper disk similar to that used in Example 1.

The solid electrolyte battery shown in the table is produced by arranging the positive electrode and negative electrode disks one above the other through a solid electrolyte molded body and press-molding at a pressure of 20 kg/ci! I assembled Arashi 9 from lhl.

After applying (charging) a constant voltage of 0.6V to both ends of these batteries for 17 hours, a constant current of 1mA was passed for 1 minute, and the difference between the battery voltage at this time and the battery voltage before passing the constant current was measured. and the polarization value.

The results are summarized in a table.

In the solid electrolyte battery 1°4.7 using the solid electrolyte molded bodies (a), (d), and (g) on the surface of which metal steel is vapor-deposited according to the present invention, the solid electrolyte molded body contains a binder. Nevertheless, batteries 3 using solid electrolyte molded bodies (c), (f), and (i) that do not contain a binder
．． It gives a small polarization value comparable to 6.9. However, the solid electrolyte molded body (b) does not have metallic copper deposited on its surface.

(e), (In battery 2, 5.8 using ~, the polarization value is 20
It shows a large value close to or exceeding 0, and lacks practicality as a battery.

In addition, examples of the binder used in the present invention include 1.
4-Polybutane diene, natural rubber, polyisoprene, S
BR, NBR, EPDM, EPM.

Urethane rubber, polyester rubber, chloroprene rubber, epichlorohydrin rubber, silicone rubber, styrene-butadiene-styrene block copolymer (SBS),
Styrene-isoprene-styrene block copolymer (S
IS), styrene-ethylene-butylene-styrene copolymer (SEBS).

Butyl rubber, phosphazene rubber, polyethylene.

Polypropylene, polyethylene oxide9. Polypropylene oxide, polystyrene, vinyl chloride, ethylene-
Ethyl acetate copolymer, 1,2-polybutadiene, epoxy resin, phenol resin.

Examples include cyclized polybutadiene, cyclized polyisoprene polymethyl methacrylate, fluororubber, and mixtures thereof.

Electrochemical devices include solid electrolyte batteries,
It can also be used in electric double layer capacitors and electrochromic display elements. Further, as a method for vapor deposition of the conductor, a normal physical vapor deposition method, such as a vacuum evaporation method using resistance heating or a sputtering method, is used.

In the vapor deposition process, the conductor that is evaporated by obtaining thermal energy and kinetic energy imparts that energy to the solid electrolyte molded body and solidifies on the surface of the solid electrolyte molded body. At this time, due to the energy received from the conductor vapor, a part of the binder near the surface of the solid electrolyte molded body becomes molten and flows, and the conductor is driven into the solid electrolyte molded body in a wedge-like state. The solid electrolyte molded body and the electrode material are well electrically and ionically bonded to each other by this wedge-shaped conductor.

In addition to the effects of the invention, according to the method according to the invention, when joining a solid electrolyte molded body and an electrode material, it is possible to improve not only mechanical strength but also electrical strength.
An electrochemical element having excellent ionic bonding can be realized.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing the relationship between the current flowing during molten precipitation of steel ions and the voltage applied to the cell. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) A method for manufacturing an electrochemical device, characterized in that solid electrolyte particles and a binder are mixed, molded to obtain a molded body, a conductor is vapor-deposited on the surface of the molded body, and an electrode is further bonded. . (2) A method for manufacturing an electrochemical device according to claim 1, characterized in that vapor deposition layers are formed on both sides of the molded body, and electrodes are bonded to the vapor deposition surfaces. (3) The method for manufacturing an electrochemical device according to claim 2, wherein one side of the electrode is a metal film and the other side is an electrode active material molded body with a metal film formed on one side.