JPS6253069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a solid electrochemical device, more specifically, a working electrode, a counter electrode facing the working electrode via a solid electrolyte layer made of an ionically conductive solid electrolyte, and a potential of the working electrode. In order to accurately detect the amount of electricity that passes between the working electrode and the counter electrode, a reference electrode is provided that is separate from the counter electrode and faces the working electrode via a solid electrolyte layer. , relates to a solid-state electrochemical element in which the potential of the working electrode relative to the counter electrode or reference electrode changes almost linearly, and when the current supply is stopped, the current potential is maintained as it is, and in particular, the above-mentioned The aim is to provide an element that is advantageous for mass production without losing its properties.

Charging, resting, and
The ideal progression of the potential of the active electrode relative to the reference electrode when discharging and resting are performed sequentially is a combination of several straight lines with breaks at each operating point, as shown in the graph in Figure 1. is shown as

An example of the construction of this type of element is shown in FIGS. 2a and 2b, as is already well known. To describe this element using a copper ion conductive solid electrolyte as an example, in the figure, 1
is a counter electrode, and is formed by press-molding a mixture of Cu ₂ S and solid electrolyte. On top of that, a solid electrolyte layer 2, a working electrode layer 3 made of a mixture of Cu ₂ S and solid electrolyte, a solid electrolyte layer 2', and a reference electrode layer 4 made of the same material as the counter electrode are formed by press molding in order. . Finally, the reference electrode and counter electrode current collector electrodes 6 and 6' are press-fitted with final pressure, and then removed from the mold to form a molded element. The current collecting electrode 5 of the working electrode is press-fitted after the device is molded, as shown in FIG. 2a, or it is press-fitted between the working electrode 5 and the solid electrolyte layer 2' during molding, as shown in FIG. 2b. After molding the device, part of the reference electrode 4 and solid electrolyte layer 2' is cut out to take out the current collecting electrode 5 of the working electrode. Next, connect lead wires 8, 8', 8'' to each current collecting electrode with solder or conductive adhesive 7,
7' and 7'' are also connected, and an exterior 9 for protecting this element is made of resin.

In such devices, the yield to obtain the operating characteristics shown in FIG. 1 is poor, and it takes a lot of effort to improve the yield. In other words, as shown in Fig. 2a, when the working electrode current collector is press-fitted after the device is molded, the current collecting electrode may be press-fitted into the working electrode, in some cases close to the reference electrode (extremely In some cases, it is press-fitted into the solid electrolyte layer 2'), and in some cases, it is press-fitted in a position closer to the opposite electrode side. In order to obtain the operating characteristics shown in Fig. 1, the position of the working electrode collector electrode must be correctly inserted at the interface between the working electrode 3 and the solid electrolyte layer 2' as shown in Fig. 2b. No. If the current collecting electrode is not inserted correctly, the operating characteristics of the element will continue to change in the direction in which the potential changed during energization (overload) even after the energization of the element is stopped, as shown in Figure 3a. (referred to as "shute"), or as shown in FIG. 3b, there is such an effect that it is difficult to maintain the potential when the current is not supplied.

On the other hand, if you try to configure it as shown in Figure 2b,
Since a portion of the reference electrode 4 and the solid electrolyte layer 2' must be cut out, it is very time-consuming to manufacture the device.

The present invention solves the above-mentioned problems and is configured so that an element as shown in FIG. 1 can be easily and simply manufactured without impairing the operating characteristics. Conventionally, in this type of element, it has been thought that in order to obtain the operating characteristics as shown in FIG. 1, it is necessary to improve the bonding state between the layers shown in FIG. 2. Therefore, as mentioned above, methods have been taken to stack each layer in a mold. Although this idea is generally correct, the present inventors found that in FIG. 2a or b, the bond between the working electrode current collector 5 and the solid electrolyte layer 2' is
I have found that it is good to use the minimum amount necessary for functionality. The present invention has been made in view of this point, and this point is considered to be outside the conventional electrochemical common sense.

An example of the configuration of the present invention is shown in FIGS. 4 and 5.
As shown in the figure. First, as shown in Figure 4a,
The reference electrode 4 and the solid electrolyte layer 2' are predetermined in size excluding the soldered portion of the active electrode current collector 5.
As shown in FIG. 4b, a tablet 20 which is made up of an integrated tablet 20 and a tablet 21 which is made up of a pair of working electrode 3, solid electrolyte layer 2 and counter electrode 1 are molded separately. ' are joined together with adhesive to form an element. If leads are attached to the current collector electrodes embedded in each electrode with solder or conductive adhesive, and the exterior is covered with resin, the fifth
The structure will be as shown in the figure. This adhesive layer 10
By making the adhesive thin enough, the adhesive is divided and stored in the unevenness of the surface of the solid electrolyte layer 2' or the surface of the working electrode 3, and the adhesive is separated from the protrusions on the surface of the solid electrolyte layer 2' and the working electrode 3. The protrusions on the surface of adhesive layer 1
It comes into direct contact without going through 0. Although the contact area between the two is very small because the protrusions on each surface are in contact with each other, it was confirmed that this is sufficient for the function.

As the adhesive, a solvent-free adhesive is suitable, and epoxy resin or cyanoacrylate resin can be used. Further, when an adhesive in which a solid electrolyte is dispersed in these adhesives is used, the bond between the working electrode 3 and the solid electrolyte layer 2' can be made stronger, making it even more effective.

Next, a specific embodiment of the present invention will be described with reference to FIGS. 4 and 5. First, as a copper ion conductive solid electrolyte, 1/5 of the Cu ⁺ ions in CuCl are converted into Rb ⁺ , K ⁺ ,
Substituted with a cation selected from NR ₄ ⁺ (R is H or an alkyl group), and substituted with a cation selected from NR 4 + ⁽ R is H or an alkyl group), and
0.6 g of 1/4 to 7/20 substituted with I ^- ions, 0.6 g of a mixture of 9 parts cuprous sulfide and 1 part of the above solid electrolyte as the counter electrode material, cuprous sulfide as the working electrode A mixture of appropriate amounts of the above solid electrolyte and
Prepare 0.6g.

Next, the above materials were loaded into a mold with an inner diameter of 15φmm in layers as shown in Figure 4b, and then 4 tons/
The tablet 21 is obtained by pressure molding at a pressure of cm ² .
At the time of molding, gold-plated copper net is used as the counter electrode current collector 6', and gold foil with a thickness of 0.1 mm is embedded as the active electrode current collector 5.

Next, as the reference electrode material, use the same material as the counter electrode material, 0.25
Prepare 0.25g of solid electrolyte. This has an inner diameter of 10φ
The tablets 20 are loaded into a mold of 1.0 mm in size in layers so as to have the configuration shown in ^FIG . After bonding tablets 20 and 21 under pressure using instant adhesive (manufactured by Toagosei Kagaku Co., Ltd.), lead wires are soldered to their respective current collecting electrodes, and they are covered with resin to form an element as shown in Figure 5. did.

As described above, the solid-state electrochemical device of the present invention can be mass-produced using automatic machines without impairing the operating characteristics of the device, has stable device characteristics with little variation, and can be provided at low cost. It is.

[Brief explanation of the drawing]

FIG. 1 is a preferred curve diagram showing the time change of the operating electrode potential with respect to the reference electrode when the solid-state electrochemical device is charged and discharged with a constant current, and FIG. 2 a and b are cross-sectional views of the conventional solid-state electrochemical device. Fig. 3 is a defective curve diagram showing the time change of the operating electrode potential with respect to the reference electrode when charging and discharging with a constant current in a conventional element, and Fig. 4 a and b are graphs for explaining the embodiment of the present invention. FIG. 5 is a perspective view of essential parts and a sectional view of a solid electrochemical device according to an embodiment of the present invention. 1...Counter electrode, 2,2'...Solid electrolyte layer, 3...
... Working electrode, 4 ... Reference electrode, 5 ... Working electrode current collector,
6...Reference electrode current collector, 6'...Counter electrode current collector, 7,
7', 7''... Connection with lead wire by solder or adhesive, 8, 8', 8''... Lead wire, 9... Exterior, 10... Adhesive.

Claims (1)

[Claims] 1. A working electrode and a counter electrode that face each other with a solid electrolyte layer made of an ion-conducting solid electrolyte provided therein, and are each provided with a current collecting electrode, and are further configured to detect the potential of the working electrode. Separately from the counter electrode, there is a reference electrode having a current collecting electrode provided opposite to the working electrode via a solid electrolyte, and the potential of the working electrode with respect to the reference electrode is such that current is applied between the working electrode and the counter electrode. A solid electrochemical element configured to change almost linearly in response to the amount of electricity supplied, the solid electrochemical element having a thin layer of adhesive between the working electrode and the solid electrolyte layer on the reference electrode side. A solid electrochemical device characterized by being provided with. 2. The solid electrochemical device according to claim 1, which uses an adhesive selected from solvent-free adhesives. 3. The solid electrochemical device according to claim 1, which uses as the adhesive a mixture in which the same solid electrolyte powder as the solid electrolyte is dispersed.