JPS5924492B2 - Filling method of active material for batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method of continuously depositing a paste-like active material into a porous foamed metal material (hereinafter referred to as foamed metal) having a three-dimensional structure with continuous spaces. The present invention relates to a method for filling a battery active material into a battery.

Conventional methods for filling this type of active material in lead batteries include filling a porous cylinder or lattice with a powder mainly containing the active material, or applying the active material in the form of a paste. However, for alkaline batteries, a method similar to the above or a method in which a sintered body is impregnated with a salt solution of the active material and converted to the active material by electrolysis, thermal decomposition, chemical treatment, etc. is used. It has been.

In such a method, in the case of a sintered body, it is necessary to repeat impregnation and conversion several times to 10 or more times, making the process complicated.

On the other hand, the method of applying a paste-like active material to a lattice, that is, a conductive porous body, is easier to manufacture than the case of a sintered body, and can be used as a screen as a conductive porous body. A continuous manufacturing method is also possible by using expanded plates, dometals, perforated plates, etc. However, in this case, the active material is bonded to the conductor using a binder, etc., and as a result, the contact with the conductor is much less than in the former case, which reduces the voltage and lifespan of the active material. It does not reach the conclusion. In addition, if this coating method can be adopted using a sintered body,
Although it is possible to take advantage of only the advantages of both, the pores of conventional sintered bodies are small, so it has been impossible to uniformly fill the inside with active material powder. However, in the case of foamed metal, which has been attracting attention recently, the porosity can be reduced to 90%.
Even with the above, it is easy to make the pore size larger than the particle size of the active material, and therefore, such a coating method can be adopted in principle.

In other words, if this foamed metal is filled with a paste mixture containing active material powder, conductive powder added as needed, a binder and its solvent, it is filled in the active material state from the beginning, so it becomes active. No conversion process is required, as would be the case if a salt solution of the substance was added.

However, there is no need to repeat filling and conversion, which simplifies the process. However, filling this foamed metal with a paste mixture mainly composed of active material powder is difficult to apply to the surface of general two-dimensionally spread screens, perforated plates, expanded metals, etc. Differently, it is necessary to fill the inside of a three-dimensional porous body.

In this case, by simply applying a paste mixture to the surface of the foamed metal, or passing the foamed metal through the paste inactive material, it will be filled uniformly considering the particle size of the paste active material and the pore size of the porous material. Although it should be possible to do so, in reality, even if the pasty active material could be filled, there was a problem in that the inside of the foamed metal was not evenly filled. In other words, in order to automatically fill a long strip of highly porous foamed metal with a pasty active material six times in a row, it is necessary to perform operations such as replacing the gas in the spaces in the foamed metal with the active material. It turned out that it does. The present invention introduces a 6-band foamed metal into a paste-like active material, and moves the paste-like active material on the surface of the foamed metal with a sliding plate that slides parallel to the foamed metal. The method is characterized in that the active material is filled into the inside of the foamed metal by performing an operation that exposes the active material intermittently.

According to the present invention, when the sliding plate slides on the surface of the foamed metal to move the paste active material, there is a paste active material containing a medium such as water between the sliding plate and the foamed metal. The space between the parts is kept airtight, and as this airtight part moves, negative pressure is applied to the exposed foam metal at the rear of the sliding plate.This causes the air in the foam metal in that area to be discharged, and the next This makes it easier to fill the active material that moves to the surface. In this way, by intermittently exposing the surface portion of the foam metal and generating negative pressure, it is possible to increase the packing density of the active material. Further, since the sliding plate 6 slides in parallel with the foamed metal 6, the negative pressure generating area can be enlarged and the filling efficiency can be improved. Two embodiments of the present invention will be explained below based on drawings showing embodiments thereof.

FIG. 1 shows a filling device for pasty active material. First, add about 10% nickel powder as a conductive material to commercially available nickel hydroxide powder. In addition. Mix and stir well, then add an appropriate amount of water or carboxymethylcellulose (CMC).
) Add the aqueous solution and stir thoroughly to make a paste-like active material. Then, put this paste-like active material 1 into an active material filling container 2, and use a stirrer. The driving motor 3 is driven to rotate the stirrer 4 so that the paste-like active material 1 is placed above the porous support plate 6 of the foamed metal 5. Then, the long strip-shaped foamed metal 5 is passed from the main shaft roller 7 to the auxiliary roller 8 , the porous support plate 6 , and the active material rubbing device 9 .
The main shaft roller 10 is attached to a plurality of flexible rubbing plates 10 made of soft synthetic resin, rubber, etc., passes through the passage 6, passes through another auxiliary roller 11, and reaches the main shaft roller 12. 7 and 12 are rotated to move the long banded foam metal 5. In this case, the main shaft roller 7
, 12 are operated, and at the same time, the active material rubbing device 9 is operated by the 1 drive motor 13. Therefore, the paste-like active material 1 is filled into the continuously moving long strip-shaped foamed metal 5 by the action of the stirrer 4 and the active substance rubbing device 9. In this case, the foam metal 5 has a width of 150 mm. A flexible rubbing plate 10 with a length of 5 m, a porosity of about 9770, and an internal volume of the active material filled part of about 501 mm is used, and a width of about 160 mm. Ten sheets with a thickness of about 3 mm were used.

Further, the amplitude of the active material rubbing device 9 was approximately 80 mm, and its moving speed was approximately 1 cycle/second. Also, the rotation speed of the stirrer 4 is 3 to 5 rotations/second 6 The moving speed of the foamed metal 5 is 0.5 m
m/sec. Fig. 2 shows the filling mechanism of the paste-like active substance carried out under these conditions. This filling mechanism 6 first stirs the paste-like active material 1 in the lower part of the foamed metal 5 with a stirrer 4, and then moves the paste-like active material 1 near the surface of the foamed metal 5 held on the porous support plate 6. The paste inactive material 1 is applied to the foamed metal 5 by the rubbing plate 10 of the active material rubbing device 9 which moves reciprocally in close proximity to or in contact with the surface of the foamed metal 5. While exposing a portion, contact with the paste-like active material 1 is maintained, and the paste-like active material 1 is forcibly moved and filled. The purpose of this filling method is to make it easy to replace most of the gas in the foamed metal 5 with the active material 1. That is, in the process of partially exposing the surface of the foamed metal 5 and reciprocating the active material rubbing device 9 having the flexible rubbing plate 10, much of the gas in the foamed metal 5 is sequentially released from the exposed portion of the foamed metal 5. The active material 1 replaces and fills that part. In this case, the exposure of the foamed metal 5 is as follows.
As shown in Figure 2. When the active material rubbing device 9 moves in the direction of arrow A. Foamed metal 5 at the rear part in the direction of movement
The surface will be exposed. Conversely, when moving in the direction of arrow B, the surface of the foamed metal 5 at the rear in the direction of movement is exposed. In addition, the foamed metal 5 is moving in one direction, and the paste-like active material 1 supplied sequentially is sent between a plurality of flexible rubbing plates 10 provided in the active material rubbing device 9. Due to the reciprocating movement, an exposed portion of the foamed metal 5 is always formed, and as a result, the active material 1 can be filled with high density. FIG. 3 shows another embodiment of the present invention.6 In this FIG. By making a circular movement in the horizontal direction relative to the foamed metal 5, a part of the surface of the foamed metal 5 is exposed while being filled with the paste inactive material.

The rotational speed of the active material rubbing device 9a in this case was 1 to 2 revolutions/second, and all other conditions were the same as in the previous example.

A conventional method for filling a paste inactive material is to simply pass foamed metal through the paste inactive material.

And paste concentration conditions in this conventional filling method,
The moving speed of the foamed metal was all the same as in the examples of the present invention, and when the amount of active material packed was measured using this conventional method, the packing density of the active material was 0.4 to 1.09/C.
It was C. Converting this into energy density, it is 17
0 to 400mAh/CC (however, the thickness of the board is 1.5m)
m). On the other hand, when the filling amount of the active material was measured using the method of the present invention, the packing density of the active material was 1.1 to 1.189/CC.

Converting this into energy density. 450-490m
This corresponds to Ah/CC (provided that the substrate thickness is 1.5 degrees). In addition, as samples, 50 substrates each having a size of 100 (i) were sampled, and the amount of active material contained in the substrates was calculated.In this way, the filling method of the present invention has a Packing density is 0.18-0.79
/within CC. The average value is 0.79/CC or 1
．． 149/CC, which is a significant improvement of about 0.449/CC.

That is, the filling method of the present invention improves the packing density by about 1.5 times or more than the conventional method. There is also variation in packing density. In the conventional method, 0.6f! /CC, whereas the present invention has a very small value of 0.089/CC. This means that the quality is very stable. FIG. 4 shows still another embodiment of the present invention, in which the bottom surface of a plurality of flexible rubbing plates 10b provided in the active material rubbing device is uneven, and the uneven parts 14 are used for each rubbing. Board 10b
They are arranged alternately.

When the active material was filled with the rubbing plate 10b having the uneven portions 14, the packing density of the active material was further increased to 2 to 3.
Improved by about 70. Also, the variation in energy density was reduced by about 70 points. It is very difficult to improve the energy density at this value, so this number? Improvement is of great significance. In addition. In FIG. 4 above, through the concave portion of the rubbing plate 10b. Since the paste-like active material moves easily between the plurality of rubbing plates 10b, this leads to an improvement in the packing density.

Also, as shown in the above embodiment, near or below the two foamed metals 5. By stirring the paste-like active material 1, it is possible to prevent the active material 6 from separating from the solution and causing the active material to settle, and also to uniformly stir the active material near the foamed metal 5, thereby dissolving the active material in the upper part. Since it is possible to prevent the solution from becoming excessive in the substance, it is possible to fill the substance with high density and uniformity. Especially when stirring near the foam metal 5.
The active material directly filled into the foamed metal 5 can be stirred sufficiently and the concentration of the active material can be prevented from changing significantly, which plays a major role in ensuring a stable filling amount of quality 6.

In general, foamed metal. Just like I did before. It is a highly porous material6 and its interior is mostly occupied by gas.

Unless this internal gas is released to the outside. It is clear that the active material is not filled, and if the entire upper part of the foamed metal is always surrounded by the paste-like active material as in the conventional method, the gas inside the foamed metal will... The active material is compressed by its weight, making it even more difficult to release it to the outside.

However, the desired active material is not filled. There is also large variation in the amount of filling. In contrast to this. In the filling method of the present invention. 6 by exposing a part of the foam metal
The pressure inside the foam metal is made equal to atmospheric pressure, making it easier for the active material to replace gas, so the active material is packed at a high density and the variation is much smaller than before. . 6 In the above example, nickel electrode active material was used as the battery active material, but
It can be similarly applied to cadmium electrodes, lead electrodes, iron electrodes, and electrode active materials for fuel cells. As described above, according to the present invention. The paste-like active material can be filled with high density, and the variation in the amount of filling can be made very small. Moreover, mass productivity can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a pasty active material filling device showing an embodiment of the present invention. FIG. 2 is a front cross-sectional view of a filling mechanism in the same device. FIG. FIG. 4 is a perspective view showing the embodiment, and FIG. 4 is an exploded view showing a state in which the concave and convex portions of the rubbing plates are alternately arranged on each rubbing plate, showing still another embodiment of the filling mechanism section. 1...Paste inactive material, 5...Foamed metal, 9...Active material rubbing device. 10...
...Flexible rubbing board.

Claims (1)

[Claims] 1 Introducing a band-shaped sponge-like porous metal body having continuous spaces into a paste-like active material,
The active material is filled into the porous body by moving the active material on the surface of the porous body with a sliding plate that slides in parallel with the porous body to intermittently expose the surface of the porous body. A method for filling an active material for a battery.