JPS6155866A - Thin type cell - Google Patents

Abstract

PURPOSE:To make it possible to form an even electrolytic liquid layer by adding a water-soluble polymer increased viscosity agent to electrolytic liquid having zinc perchlorate as an electrolyte and water as a catalyzer while forming an electrolytic liquid layer on an active material layer or on a separator face at least either of a negative pole and a positive pole by screen printing. CONSTITUTION:A negative pole active material layer 2 mainly composed of zinc powder is formed on a negative pole collector 1 laminated with a conductive film and an aluminium foil while an electrolytic liquid layer 6 is formed on said negative pole active material layer. Further, a positive pole active material layer 3 mainly composed of manganese dioxide is formed on a positive pole collector while midway of these a separator 4 of a synthetic resin nonwoven fabric is interposed. The concentration of zinc perchlorate in the electrolytic liquid shall be 1.5-2.5M/l and hydroxyethylcellulose is used as a polymer increased viscosity agent while concentration of its addition shall be 1.5-5wt% and the electrolytic liquid layer 6 is formed on the negative pole active material layer 2 by screen printing.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electrolyte solution for a thin battery, in particular a thin battery in which a uniform electrolyte layer is formed on a negative electrode active material without deteriorating the negative electrode active material. It is related to batteries.

<Prior Art> Recently, as electronic devices have become smaller and lighter and IC cards have become more popular, thinner and more flexible batteries, which serve as their power sources, have become important issues.

Generally, the structure of a thin battery is as shown in Figure 1, with the positive and negative electrode current collectors (2) being films made by laminating aluminum foil and conductive film, and the positive electrode active material layer (3) mainly consisting of manganese diaate. , a negative electrode active material layer (2) mainly made of zinc powder, and a separator (4) made of synthetic resin.

The separator contains an electrolyte containing ammonium chloride and zinc chloride as electrolytes and water as a solvent.

Conventionally, in order to apply electrolytic solution to the separator of these type 5 type thin batteries, the separator was immersed in the electrolytic solution, or the electrolytic solution was injected into the structure during lamination. There have been problems such as uneven application of the electrolyte, leakage of the electrolyte, and troublesome handling during the manufacturing process.

In order to solve these problems, an auxiliary material is added to an aqueous solution of ammonium chloride and zinc chloride, and this is applied to the active material layer.

However, according to this method, when the negative electrode active material is coated with the electrolytic solution, deterioration progresses during storage in the air after coating, reducing the utilization rate of the active material.

<Problems to be Solved by the Invention> The present invention eliminates these drawbacks and provides a thin battery that enables the formation of a uniform electrolyte layer and has excellent storage stability of the negative electrode active material after the electrolyte layer is formed. It provides:

<Means for solving the problem> That is, the positive electrode active material of the present invention mainly contains manganese dioxide,
In thin batteries where the negative electrode active material is mainly zinc, a water-soluble polymer thickener is added to an electrolytic solution in which the electrolyte is zinc perchlorate and the solvent is water to form an active material layer on at least one of the negative electrode and the positive electrode. Alternatively, an electrolyte layer is formed on the separator surface by screen printing, and the concentration of zinc perchlorate in the electrolyte is 1.5 to 2.5 M/l, and the polymer thickener is hydroxyl. This is a thin battery in which the electrolyte is made of ethyl cellulose and has an added concentration of 1.5 to 5 wt%.

In a thin battery, as shown in FIG. 1, the size of the separator (4) is generally smaller than the current collector (1). Therefore, in the case of mass production, the separator is cut into pieces for each thin battery, but the current collector is supplied in the form of continuous sheets or rolls for multiple thin batteries, and the active material layer and electrolytic It is more advantageous in terms of production efficiency to form the liquid layer into individual strips for a plurality of thin batteries by printing.

If an electrolytic solution with a zinc perchlorate concentration of 1.0M or less is printed on the negative electrode active material, the negative electrode active material will deteriorate, and the zinc perchlorate concentration will be 2.5M or less.
If the concentration exceeds 15 to 2, it will no longer dissolve.
．． 5 M/l is preferable.

Polymer thickened shaved hydroquine ethyl cellulose is 1,5
Below m t%, the electrolyte viscosity is below 500 cps, and above 50 m %, it is over 10,000 cps. In order to uniformly apply the electrolyte layer, the hydroxyethylcellulose concentration must be 1.5 to 5.0 m t. % is a necessary condition for forming a uniform electrolyte layer.

<Example> The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing a cross section of a thin battery that is an embodiment of the present invention. Referring to the figure, in the figure.

(1) is a positive and negative electrode current collector made by laminating a 0.03 mm conductive film and a 0.03 mm aluminum foil, and the negative electrode current collector has a negative electrode active material layer (based on zinc powder).
2) is formed, and electrolysis g1 is formed on this negative electrode active material layer.
A layer (6) is formed. Further, a positive electrode active material N (3) mainly composed of manganese dioxide is formed on the positive electrode current collector, and a 0.06 mm synthetic resin nonwoven fabric separator (4) is interposed in between. A frame material (5) is interposed in the peripheral portion, and is finally heat-sealed.

The electrolytic solution was thickened by adding 3 wt % of hydroxyethyl cellulose to a zn (CJ, 04) 26H202M solution, and an electrolytic solution layer was formed on the negative electrode active material layer using a 100 mesh screen plate.

The negative electrode active material coated with electrolyte was left for 10 days, the constituent materials of each layer were stacked together as shown in the same figure, and the periphery was heat-sealed.
The stacked thin batteries were left horizontally. As a result, the electrolytic layer penetrates into the separator, and this sheet-like battery becomes 186
An open circuit voltage of V can be obtained, and 0.1 g of negative electrode active material
The discharge capacity of the thin battery of this example containing zinc is 80
mAh, and the zinc utilization rate was 98%.

<Effects of the Invention> Since the present invention is as described above, it produces the following excellent effects.

A polymer thickener is added to an ammonium chloride/zinc chloride electrolyte, and it was difficult to apply it to the surface of the negative electrode active material because it would accelerate the deterioration of the zinc. By using an aqueous solution of zinc perchlorate with the addition of a molecular thickener, especially hydroxyethyl cellulose, an electrolyte layer can be formed on the surface of the negative electrode active material and stored for several days before being applied to the battery structure. is possible.

In this way, the electrolytic solution composition of the present invention can be applied in advance onto any or more of the negative electrode active material layer, the positive electrode active material layer, and the separator, and the electrolyte composition can be applied to the electrolytic solution layer on the most easily layered layer in terms of the manufacturing process. It has the advantage that it can be formed in advance.

Furthermore, the electrolyte layer applied in this way is uniform;
After being assembled into a thin battery, it permeates evenly into the separator, and there is less flow of electrolyte after permeation, which reduces leakage accidents.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the cross section of the thin battery according to the present invention, Figure 2
The figure is a graph showing the amount of gas generated. 1. Current collector 2. Negative electrode active material layer 3 Positive electrode active material layer 4 Separator 5 Frame material 6 Electrolyte layer

Claims (4)

[Claims] (1) In a thin battery where the positive electrode active material is mainly manganese dioxide and the negative electrode active material is mainly zinc, a water-soluble polymer thickener is added to the electrolyte where the electrolyte is zinc perchlorate and the solvent is water. By screen printing on the active material layer or separator surface of at least one of the negative electrode and the positive electrode,
A thin battery characterized by forming the electrolyte layer. (2) The molar concentration of zinc perchlorate in the electrolyte is 1.5
2.5M. The thin battery according to claim 1. (3) The thin battery according to claim 1, wherein the polymer thickener in the electrolyte is hydroxyethylulose. (4) The thin battery according to claim 3, wherein the weight concentration of hydroxyethylcellulose in the electrolyte is 1.5 to 5.0% by weight.