JPH08339803A - Manufacture of battery electrode and device - Google Patents

Abstract

PURPOSE: To stabilize battery performance of a battery using the electrode, and improve productivity by always keeping to be constant an applying amount of battery material to an electrode base board. CONSTITUTION: A slurry-like battery material vessel 1 and a slurry-like battery material stock tank 10 are connected, and a slit 5 is provided above the slurry- like battery material vessel 1. The slit 5 scrapes extra slurry-like battery material 2 out of both faces of long-size electrode base board 4 to which slurry-like battery material 2 is applied when the same passes inside the slurry-like battery material vessel 1. A sensor 7 measuring liquid level height of the slurry-like battery material vessel 1 is provide so that the slurry-like battery material 2 is fed from the slurry-like battery material stock tank 10 to the slurry-like battery material vessel 1 when the liquid level thereof becomes low or high against a setting value. Or, the feeding of the slurry-like battery material 2 to the slurry-like battery material vessel 1 is stopped, or reversely the slurry-like battery material 2 is fed from the slurry-like battery material vessel 1 to the slurry-like battery material stock tank 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electrode used in a battery such as a nickel-hydrogen battery and a device therefor.

[0002]

2. Description of the Related Art Nickel-cadmium batteries, nickel-
Storage batteries such as hydrogen batteries are widely used as a power source for various electric devices.

The manufacturing method of the outline of the electrode plate of these batteries differs depending on the positive electrode and the negative electrode, but it is generally as follows. First, for the positive electrode, a method in which a foamed metal having a high porosity and a continuous three-dimensional network structure is filled with a slurry-like active material has recently become the mainstream. On the other hand, for the negative electrode, a method in which a slurry-like battery material is applied to both surfaces of a punching metal sheet having a thickness of about 0.1 mm and having holes having a diameter of about 1 to 2 mm is mainly used. Then, each is dried by an appropriate method, and the original plate of the electrode plate is manufactured through post-processes such as pressure pressing and surface treatment.

In the method of manufacturing the above-mentioned electrode plate, the method of coating the negative electrode is generally known as shown in FIG. A long electrode substrate (4) made of a sheet-shaped punching metal sheet is placed in a slurry-like battery material tank (1) (hereinafter referred to as a slurry tank) filled with a slurry-like battery material (2) (hereinafter referred to as slurry). Soak with a rotating roll (3). As a result, the slurry (2a) is attached to both surfaces of the substrate (4a) coming out of the slurry tank (1). The substrate (4a) is pulled up as it is, and the excess slurry (2b) is scratched by the slit (5) to obtain a substrate (4b) having an appropriate slurry thickness. Then, it is dried and the slurry coating is completed.

By the way, in the above process, the influence of the gravity of the slurry unavoidably occurs. That is, a large amount of the slurry adheres to both surfaces of the substrate immediately after the substrate exits the slurry tank, but as time elapses, the slurry drops downward, and the amount of the adhered slurry decreases. If the adhered amount is not constant, the following problems occur.

As shown in FIG. 2 (a), when a large amount of slurry (2a) adheres to the substrate (4) and reaches the slit (5), a large amount of slurry (2b) accumulates on the primary side of the slit, As a result, the pressure inside the slit increases, and the slurry coating thickness (6) on the secondary side of the slit increases.
On the other hand, as shown in FIG. 2B, when the amount of attached slurry on the substrate is small, the slurry does not stay on the primary side of the slit, and as a result, the pressure does not rise and the slurry coating thickness on the secondary side of the slit (6) Becomes smaller.

[0007]

It is desired that the slurry coating amount (thickness) is constant from the viewpoint of battery performance and productivity, and from the above description, it is possible to stabilize the slurry deposition amount on the primary side of the slit. It is indispensable to do so, and the present invention provides a method for stabilizing the slurry adhesion amount on the primary side of the slit.

[0008]

DISCLOSURE OF THE INVENTION As a result of studies in view of this, the present invention has developed a method and an apparatus capable of always maintaining a constant slurry coating thickness on an electrode substrate.

That is, in the method of the present invention, a long electrode substrate is continuously passed through a slurry tank to coat the slurry on both surfaces of the substrate, and then the substrate is placed between slits having a predetermined opening width. In the method for manufacturing a battery electrode in which the excess slurry on both sides of the substrate is scraped off by passing it from below, the distance between the liquid surface of the slurry tank and the slit is made substantially constant, and at this time the slurry is used. It is effective to keep the error between the liquid level in the tank and the slit within ± 2 mm.

In the apparatus of the present invention, a slurry tank and a slurry-like battery material stock tank are connected to each other and passed through the slurry tank to remove excess slurry from both surfaces of the long electrode substrate coated with the slurry. A slit for scraping is provided above the slurry tank, and further has a sensor for measuring the liquid level height of the slurry tank, and when the liquid level becomes lower or higher than a set value. The slurry is sent from the slurry-like battery material stock tank to the slurry tank, or the supply of the slurry to the slurry tank is stopped, or conversely, the slurry is sent from the slurry tank to the battery material stock tank.

In another apparatus of the present invention, a slurry tank and a slurry-like battery material stock tank are connected to each other and passed through the slurry tank so that excess slurry is applied from both sides of the long electrode substrate coated with the slurry. A slit for scraping off the slurry is provided above the slurry tank, and further has a sensor for measuring the thickness of the long electrode substrate passing through the slit, and the thickness of the long electrode substrate measured by the sensor. Is provided with a mechanism for automatically adjusting the distance between the liquid level of the slurry tank and the slit.

The mechanism for automatically adjusting the distance between the liquid surface and the slit is as follows. For example, when the thickness of the long electrode substrate that has passed through the slit becomes smaller than the set value, the slurry-like battery material is fed from the slurry-like battery material stock tank to the slurry tank, and this thickness is increased. In that case, the supply of the slurry to the slurry tank is stopped, or a device for sending the slurry from the slurry tank to the battery material stock tank, or when the above-mentioned thickness becomes smaller than the set value, the slurry tank itself is raised. And a device for lowering the slurry tank itself when the thickness becomes larger than the set value.

[0013]

The amount of slurry deposited on the primary side of the slit is mainly determined by the viscosity, the substrate transport speed, and the slurry liquid level to the slit distance. Among them, the slurry liquid level to the slit distance usually becomes smaller as the slurry is applied, and is not stable. Therefore, in the present invention, the slurry liquid level is always checked by the sensor, and the slurry liquid level height, that is, the slurry liquid level to the slit distance, is obtained by adding or withdrawing the slurry so as to have a constant slurry liquid level. It is kept constant to stabilize the amount of attached slurry on the primary side of the slit.

Further, in the present invention, the thickness of the substrate on the secondary side of the slit after the slurry coating is directly measured, and the slurry is added to or withdrawn from the slurry tank according to the signal, so that the liquid surface height of the slurry tank is increased. The slit coating amount is adjusted to be constant on the secondary side of the slit.

[0015]

EXAMPLES Examples of the present invention will be described below.

(Example 1) FIG. 1 is an explanatory view of slurry coating according to the present invention. The substrate (4) passes through a slurry tank (1) filled with the slurry (2) along a rotating roll (3), and is pulled up with the slurry (2a) attached. After that, the excess slurry (2b) is scraped off at the slit (5). Here, the sensor (7) detects the liquid level, and the pump (8) transfers the slurry from the slurry-like battery material stock tank (10) (hereinafter referred to as the slurry stock tank) to the slurry tank (1).
Or to withdraw the slurry from the slurry tank (1) and return it to the slurry stock tank (9). When the sensor (7) detects that the slurry (2) inside the slurry tank (1) has decreased (the liquid level has dropped) as the slurry coating work progresses, the pump (8) causes the slurry stock tank (10) to The slurry of 1) is supplied to the slurry tank (1), and the amount of slurry (slurry liquid level height) inside the slurry tank is kept constant.

In this example, the measuring accuracy of the sensor (7) is ± 1.
Use an ultrasonic type of about mm, and start the slurry replenishment by the pump when the liquid surface height is 2 mm lower than the set value, and supply the slurry by the pump when the liquid level height is 2 mm higher than the set value. Stopped. With this control, the fluctuation range of the liquid surface height was suppressed to within 4 mm, and the amount of slurry adhering to the substrate on the primary side of the slit could be made substantially constant. As a result, the error in the thickness of the substrate after passing through the drying furnace on the secondary side of the conventional slit was ± 0.03 mm, but according to the present invention, it could be suppressed to within ± 0.02 mm.

(Example 2) In Example 1 above, the height of the slurry liquid surface was always constant, but in this embodiment, the height of the slurry liquid surface was adjusted to adjust the final slurry coating amount. That is, in FIG. 1, the amount of coating slurry (coating thickness) on the substrate after passing through the slit is measured by a sensor (9), and if it is thicker than a set value, the height of the slurry liquid surface is lowered. If the liquid surface is lowered, the distance between the slit and the liquid surface of the slurry is increased as described above, and the amount of slurry adhered to the substrate on the primary side of the slit is reduced. As a result, it is possible to reduce the amount of slurry applied after scraping off the slurry on the secondary side of the slit. If the coating amount (coating thickness) is less than the set value, the opposite is true. When increasing the height of the slurry liquid level, the pump is rotated normally (from the stock tank to the slurry tank), and when decreasing the height, the pump is rotated reversely.

As a method of automatically keeping the liquid level of the slurry tank constant or adjusting the liquid level automatically in the above embodiment, the slurry tank itself is moved up and down in conjunction with the sensor. It is also possible.

[0020]

As described above, according to the present invention, since the coating amount of the battery material on the electrode substrate is always constant, the battery performance of the battery using this electrode is stable and the productivity is improved. It has a remarkable industrial effect.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining the coating state of the slurry.
(B) Both are enlarged side views of the slit portion.

FIG. 3 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 1 Slurry Battery Material Tank 2 Slurry Battery Material 3 Rotating Roll 4 Battery Substrate 5 Slit 6 Coating Thickness 7 Liquid Level Height Sensor 8 Pump 9 Coating Thickness Sensor 10 Slurry Battery Material Stock Tank

Claims (3)

[Claims] 1. A slurry-type battery material is applied to both surfaces of the substrate by continuously passing a long electrode substrate through a slurry-type battery material tank, and then the substrate is provided between slits having a predetermined opening width. In a method for manufacturing a battery electrode in which excess slurry-like battery material on both sides of a substrate is scraped off by passing the slurry-like battery material tank from below, the distance between the liquid surface of the slurry-like battery material tank and the slit is substantially constant. Manufacturing method of battery electrode. 2. A slurry-type battery material tank is connected to a slurry-type battery material stock tank, and the slurry-like battery material is applied to the slurry-type battery material tank by passing through the slurry-type battery material tank. A slit for scraping off excess slurry-like battery material is provided above the slurry-like battery material tank, and a sensor for measuring the liquid level of the slurry-like battery material tank is provided, and the liquid level height is set. When it becomes low or high with respect to the value, the slurry-like battery material is sent from the slurry-like battery material stock tank to the slurry-like battery material tank, or the supply of the battery material to the battery material tank is stopped, Alternatively, on the contrary, the battery electrode manufacturing apparatus is characterized in that the battery electrode is sent from the battery material tank to the battery material stock tank. 3. A slurry type battery material tank is connected to a slurry type battery material stock tank and is passed through the slurry type battery material tank from both sides of a long electrode substrate coated with the slurry type battery material. A slit for scraping off excess slurry-like battery material is provided above the slurry-like battery material tank, and further has a sensor for measuring the thickness of the long electrode substrate that has passed through the slit, and is measured by the sensor. A battery electrode comprising a mechanism for automatically adjusting the distance between the liquid surface of the slurry-like battery material tank and the slit by comparing the thickness of the long electrode substrate with a set value. Manufacturing equipment.