JPH117947A - Paste application device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the solidifying of paste in the vicinity of a liquid level by comprising plural pairs of first stirring rollers impregnated in the paste in a container to supply a power collector sheet upwardly and stir the paste and at least one pair of second stirring rollers provided in the vicinity of a side wall of the container to stir a paste liquid level. SOLUTION: A paste is entered up to a liquid level of a stationary operation, the paste is stirred by impregnation stirring rollers 2a, 2b, 3a, 3b, 4a, and 4b, a work P is supplied at the stationary speed while stirring a paste liquid level 9 by liquid level stirring rollers 5a and 5b, and an excess adhered paste is scuffed off from the work P by a doctor blades 6a and 6b. Growth of a solidified paste whose initial points are container side walls 1a and 1b is efficiently inhibited by stirring the liquid level 9 by the liquid level stirring rollers 5a and 5b. In addition, a paste in a fluid state from the slide walls 1a and 1b is always supplied to the work P in a sufficient quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste applying apparatus for applying a paste containing an active material to a current collector sheet.

[0002]

2. Description of the Related Art In recent years, demand for high-performance, high-capacity batteries has increased, and various secondary batteries such as nickel-metal hydride secondary batteries and lithium ion secondary batteries have been developed and put into practical use. For example, in a nickel-metal hydride secondary battery, a stacked electrode group including a positive electrode sheet / separator / negative electrode sheet is liquid-tightly sealed in an outer container together with an alkaline electrolyte. A felt-like current collector to which a paste containing an active material is applied is used for the stacked electrode group. In a conventional paste application device,
While stirring the paste in the container with a plurality of pairs of immersion rollers, the felt-like current collector is fed upward from the container bottom,
Immediately after coming out of the liquid level, excess paste is scraped off from the current collector with a doctor blade.

[0003]

However, in the conventional apparatus, if the paste application operation is continued for a long time, the paste near the liquid level in the container solidifies, and the paste level in the container becomes high. Is erroneously detected. This is because if the nickel-containing paste is left stationary for a long time without stirring, the viscosity increases and it becomes difficult to stir. This property is called thixotropy. The liquid level of the nickel-containing paste becomes hard in the container due to the thixotropy and drying, and solidifies.

When the liquid level paste is erroneously detected due to the solidification of the liquid level paste, the paste is not newly supplied into the container even though the liquid level is actually lowered, and the paste in the container is not supplied. The amount is insufficient, and the amount of paste applied to the current collector sheet varies.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a paste coating apparatus capable of preventing solidification of a paste near a liquid surface and constantly detecting a paste liquid level in a container. The purpose is to do.

[0006]

A paste application device according to the present invention is a paste application device for applying a paste to a current collector sheet, and a container for accommodating the paste and supplying the paste into the container. Paste supply means, a plurality of pairs of first stirring rollers immersed in the paste in the container to feed the current collector sheet upward and to stir the paste, and a container provided near the side wall of the container And at least one pair of second stirring rollers for stirring the liquid level of the paste inside.

Further, it is desirable to have a liquid level detecting sensor which is provided closer to the current collector sheet than the second stirring roller and detects the liquid level of the paste in the container. Since the liquid level of the paste in the container is constantly agitated by the second stirring roller, the paste near the liquid level always moves and maintains a low viscosity state. As a result, the paste does not solidify on the liquid surface due to thixotropic properties, drying, etc., and the paste liquid level in the container is accurately detected. Therefore, even in a long-time continuous operation, the amount of the paste in the container does not become insufficient, and a sufficient amount of the paste can be applied to the current collector sheet.

It is desirable that the second stirring roller is rotated in a direction in which the paste on the liquid surface is fed from the side wall of the container toward the current collector sheet in the center of the container. In this way, the growth of the solidified paste starting from the side wall of the container is effectively prevented, and the fluid paste is always supplied from the side wall of the container to the center of the container, so that a sufficient amount of paste is applied to the current collector sheet. You.

[0009]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the work P is introduced into the container from the bottom 1c of the paste container, and the two pairs of immersion stirring rollers 2a, 2b, 4
a and 4b are supplied to the upper doctor blades 6a and 6b. In the container, three pairs of immersion stirring rollers 2a, 2b, 3a, 3b, 4a, 4b are immersed in the paste, and the paste in the container is stirred.

A pair of liquid level stirring rollers 5a and 5b are provided near the container side walls 1a and 1b, respectively, to stir the liquid level of the paste in the container. The liquid level stirring rollers 5a and 5b apply the liquid level paste to the side wall 1 of the container.
It rotates in the direction of feeding from the a and 1b toward the current collector sheet P at the center of the container.

As shown in FIG. 2, two nozzles 7a, 7
b is away from the pass line of the work P, and
It is provided near each of the liquid level stirring rollers 5a and 5b. Paste is supplied from a paste supply source 8 to each of the nozzles 7a and 7b based on a command signal from the controller 10.

A liquid level detecting sensor 11 is provided so as to face the paste liquid level 9 in the container. The sensor 11 is located closer to the workpiece P than one of the liquid level stirring rollers 5a. The sensor 11 is connected to an input side of the controller 10 and sends liquid level detection information to the controller 10.

Next, a case where the paste is continuously applied to the work P using the above-described apparatus will be described. The paste is accommodated in the container up to the liquid level of the steady operation, and the paste in the container is stirred by the immersion stirring rollers 2a, 2b, 3a, 3b, 4a, 4b, and the liquid level of the paste is stirred by the liquid stirring rollers 5a, 5b. While stirring the work 9, the work P is fed at a steady speed, and the doctor blades 6a and 6b scrape off excess adhered paste from the work P. By stirring the liquid surface 9 with these liquid level stirring rollers 5a, 5b, the growth of the solidified paste starting from the container side walls 1a, 1b is effectively prevented. In the center of the container, the container side walls 1a, 1b
Since the paste in the fluid state is always supplied from the side,
A sufficient amount of paste is always supplied to the work P, and a required amount of paste is applied to the work P.

When the paste liquid level in the container falls during continuous operation for a long time and most of the liquid level stirring rollers 5a and 5b are exposed, the sensor 11 informs that the paste liquid level has dropped. The detection signal is sent to the controller 10. Based on this, the controller 10 controls the paste supply 8
The paste supply source 8 supplies a required amount of paste into the container via the nozzles 7a and 7b in accordance with the command signal.

In this way, the paste in the vicinity of the liquid level in the container is agitated and constantly kept in a fluidized state, and the liquid level of the paste in the container does not solidify due to thixotropy and drying. Erroneous detection is eliminated.
For this reason, a desired amount of paste is always applied to the work P in an optimal state, and a high-quality secondary battery electrode can be provided.

[0016]

According to the present invention, since the liquid level of the paste in the container is constantly agitated by the second stirring roller, the paste near the liquid level always moves and is maintained at a low viscosity. Therefore, the paste does not solidify on the liquid surface due to thixotropy or drying, and the paste liquid level in the container is accurately detected. Therefore, even in a long-time continuous operation, the amount of the paste in the container does not become insufficient, and a sufficient amount of the paste can be applied to the current collector sheet.

[Brief description of the drawings]

FIG. 1 is a cross-sectional block diagram showing a paste application device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a part of the paste application apparatus according to the embodiment of the present invention.

[Explanation of symbols]

1a, 1b: Container side wall, 1c: Container bottom, 2a, 2b,
3a, 3b, 4a, 4b: immersion stirring roller (first stirring roller), 5a, 5b: liquid level stirring roller (second stirring roller), 6a, 6b: doctor blade, 7a, 7b
... Nozzle, 8 ... Paste supply source, 9 ... Paste liquid level, 1
0: Controller, 11: Sensor, P: Work (current collector sheet).

Claims (3)

[Claims] 1. A paste application device for applying a paste to a current collector sheet, comprising: a container for accommodating the paste;
Paste supply means for supplying paste into the container;
A plurality of pairs of first stirring rollers that are immersed in the paste in the container to feed the current collector sheet upward and agitate the paste, and a liquid of the paste in the container provided near the side wall of the container. A paste application device, comprising: at least one pair of second stirring rollers for stirring a surface. 2. The apparatus according to claim 1, further comprising a liquid level detecting sensor provided closer to the current collector sheet than the second stirring roller and configured to detect a liquid level of the paste in the container. The paste application device according to the above. 3. The paste coating apparatus according to claim 1, wherein the second stirring roller rotates the paste on the liquid surface in a direction to feed the paste from the side wall of the container toward the current collector sheet in the center of the container.