JPH081801B2 - Method for manufacturing sheet electrode - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sheet-shaped electrode which suppresses variations in thickness.

[0002]

2. Description of the Related Art In order to produce a sheet-like electrode composed of a mixture containing manganese dioxide as a main component, the mixture is kneaded in advance, its viscosity is adjusted to 4000 to 6000 poise, and a screw is sandwiched with a metal collector. By extruding the kneading mixture through an extruder, a sheet electrode having the metal current collector integrated therein can be obtained.

Although the thickness of the obtained sheet-like electrode conventionally varies depending on the extrusion molding temperature, the screw rotation speed, the take-up speed, etc., generally the head temperature is 70 ° C. and the screw rotation speed is constant at 30 rpm. It is set to a value, the thickness of the sheet-shaped electrode drawn out from the extruder is measured, and the speed of the take-up roller is adjusted according to this thickness to keep it within a certain range. The speed is about 5 to 6 m / min.

[0004]

However, according to the thickness adjusting method by adjusting only the extrusion speed, there is a large variation of about ± 0.1 to 0.2 mm with respect to the target value of the thickness,
It is difficult to obtain stable quality, and if the dimensional tolerance is set to be small from the viewpoint of quality control, the yield becomes extremely low.

The present invention has been made to solve the above problems. By keeping the viscosity of the kneading agent near the extrusion head within a certain range, variations in thickness can be suppressed, quality can be improved, and yield can be improved. It is an object of the present invention to provide a method for manufacturing a sheet-shaped electrode that can improve

[0006]

In order to achieve the above-mentioned object, the present invention integrates with a metal current collector by extruding a kneading agent sandwiching a metal current collector having a large number of punching holes. In the method for producing a sheet-shaped electrode, the kneading mixture has a viscosity of 600 to 1 at a head temperature of 40 to 50 ° C. when put into an extruder.
It is 500 poise, and the extrusion speed of the sheet electrode is 7
It is characterized in that it is set to 12 m / min.

[0007]

In the kneading agent having the above viscosity range, the thickness variation in the state of being formed into a sheet-like electrode by extrusion becomes extremely smaller than the conventional variation.

[0008]

EXAMPLE An example of the method of the present invention will be described in detail below.
It [Composition of kneading agent] Manganese dioxide 70 (weight, the same applies hereinafter)% Conducting agent 5 PVB 10 Teflon dispersion 5Alcohol 10  100% in total [Kneading process] Kneading with a composition of at least 70% at a kneading temperature of 70 ° C
When kneading for about 70 minutes with a mixer, the viscosity is 800 poise.
The kneading agent is completed. In addition, kneading time and mixture viscosity and
The relationship between the mixture viscosity and the temperature is shown in FIGS. 1 (a) and 1 (b).
If the kneading time is too long, the viscosity will decrease.
Then, it is desirable to stop the kneading in about 70 minutes.

[Extrusion Step] The mixture obtained in the kneading step is put into the extrusion molding machine 1 shown in FIG. 2 to perform the extrusion operation. This extrusion molding machine 1 has a screw 2 for extrusion inside, and an extrusion head 1a is supplied with a metal current collector 3 having a large number of punched holes, and the current collector 3 is sandwiched by a mixture. It is extruded by and is taken by the take-off roller 4,
It is formed on the sheet electrode 5. A thickness meter 6 is arranged at the tip of the extrusion head 1a to constantly monitor the thickness.

FIG. 3 shows the relationship between the mixture viscosity, the extrusion speed, and the variation in sheet thickness when molded at a head temperature of 50 ° C. and a screw rotation speed of 30 rpm. In the figure, when the mixture viscosity exceeds 1500 poise, the dispersion rapidly increases, and when it is less than 600 poise, it is too soft and extrusion becomes difficult, and peeling from the current collector 3 easily occurs. On the other hand, if the extrusion speed is less than 7 m / min, irregularities are likely to occur on the surface of the sheet-shaped electrode, while if it exceeds 12 m / min, it is too fast and the mixture does not adhere well to the current collector 3, resulting in current collection. Body 3 is exposed. Therefore, in the present invention, at a head temperature of 50 ° C., the viscosity of the kneading agent is preferably set to 600 to 1500 poise, and the extrusion speed is preferably set to 7 to 12 m / min.

In particular, when a sheet-like electrode having a thickness of 0.7 mm and a width of about 25 mm is formed by using the above kneading agent having a viscosity of 800 poise at a head temperature of 50 ° C., a screw rotation speed of 30 rpm and a speed of 10 m / min, The degree of variation is 0.
The value is 7 mm ± 0.01 mm, which is one digit lower than the variation in the thickness of the conventional sheet electrode.

[0012]

As described above in detail with reference to the embodiments, in the method for manufacturing a sheet electrode according to the present invention, the variation in thickness in the state of being formed into a sheet electrode by extrusion is different from the conventional variation. Very small compared to
There is an advantage that a stable quality can be obtained, the yield can be greatly improved, and the productivity can be improved.

[Brief description of drawings]

FIG. 1A is a graph showing the relationship between kneading time and mixture viscosity. (B) is a graph showing the relationship between the mixture viscosity and the temperature.

FIG. 2 is an explanatory view showing an extrusion molding machine to which the method of the present invention is applied.

FIG. 3 is a graph showing the relationship between the mixture viscosity at the time of molding, the extrusion rate, and the variation in sheet thickness.

[Explanation of symbols]

 1 Extrusion Molding Machine 1a Head 2 Screw 3 Metal Current Collector 4 Pulling Roller 5 Sheet Electrode 6 Thickness Meter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Suzuki 5-36-1 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. (72) Inventor Yukio Endo 5-36-11 Shinbashi, Minato-ku, Tokyo Fuji Electrochemical Co., Ltd.

Claims (1)

[Claims] 1. A method for producing a sheet-like electrode integrated with a metal current collector by extruding a kneading agent with a metal current collector having a large number of punched holes between the kneading agent. Has a viscosity of 600 to 15 at a head temperature of 40 to 50 ° C. when placed in an extruder.
00 poise, and the extrusion speed of the sheet electrode is 7
~ 12 m / min, the method for manufacturing a sheet electrode.