JP3412437B2 - Alkaline storage battery - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline storage battery, and more particularly, to an improvement of a battery electrode in which a space of a metal porous body having a three-dimensionally continuous space is filled with an active material.

[0002]

2. Description of the Related Art With the development and practical use of various electric devices, a small secondary battery which can be charged and discharged has become widespread as a power source. Typical examples of the small secondary battery are alkaline storage batteries such as nickel-cadmium storage batteries and nickel-hydrogen storage batteries, and these batteries are required to have higher capacities.

Such alkaline storage battery electrodes include paste type electrodes, sintered type electrodes, and pocket type electrodes. In recent years, as a positive electrode for alkaline storage batteries, a paste type electrode, which can be expected to have a particularly high capacity, has been adopted, and as a new manufacturing method thereof, a paste-shaped base material made of a sponge-like metal porous body having a three-dimensionally continuous space portion is used. A method of filling a kneaded product is often used.

Since this porous metal body has a porosity of about 95% and the pore diameter of the space portion reaches several hundreds μm at the maximum, it is possible to directly fill the paste-like active material or the active material powder with a simple process. The electrode can be manufactured with.

In such a method of manufacturing a paste type electrode, at least a part of one edge of one surface of a strip-shaped metal porous body having a space which is three-dimensionally continuous is pressurized to predetermined a compression portion. After supporting the one surface of the porous metal body, the opening length is almost the same as the width of the porous metal body that is brought close to the opposite surface of the porous metal body while supporting the one surface of the porous metal body. The paste-like kneaded material mainly containing the active material is discharged from the nozzle to fill the inside of the porous metal body. In this case, the compressed portion of the porous metal body is substantially non-porous due to the pressurization, and the compressed portion is not filled with the active material. Then, this electrode is cut into a predetermined size, and one end of a lead piece is spot-welded to this compression portion to form, for example, a positive electrode plate.

[0006]

However, in the above-mentioned method of construction, when a pressurized compression portion is provided on a part of one surface of the porous metal body, the active material is filled from the opposite side. Since the active material to be filled by this compressed portion acts as a barrier and bounces back and enters the space of the porous body from the cut end of the recessed portion facing the compressed portion, the vicinity of the recessed portion facing the compressed portion is more active than other portions. The filling amount of the substance increases.

On the contrary, when a pressurized compression portion is provided on a part of one surface of the porous metal body and the active material is filled from the same side, the compression portion is almost non-porous and the active material is The particles are bounced off, and almost no filling is possible, and the active material pressed by the filling pressure escapes from the surroundings from the cut end of the recess facing the compression section. As a result, the filling amount of the active material in the vicinity of the lower side of the compressed portion of the porous metal body becomes smaller than that in other portions.

As described above, the amount of the active material most concerned with the discharge capacity of the battery is different from the other portions in the porous body portion facing the recess near the compression portion connecting one end of the lead piece. There was a big problem of variation.

The present invention solves the above problems and constitutes an electrode in which a metal porous body is uniformly filled with an active material, and an alkaline storage battery is constructed by using the electrode, so that the discharge capacity of the battery varies. It is intended to provide a small amount of alkaline storage battery.

[0010]

In order to achieve the above-mentioned object, the present invention provides a predetermined interval on at least one edge of at least one end of a strip-shaped metal porous body having three-dimensionally continuous spaces. After providing the compressed portion at the center of the thickness by pressing from both front and back surfaces, one side of this porous metal body is supported, and while moving this, the porous metal body is brought close to the opposite surface of the porous metal body. Is a method for manufacturing a battery electrode in which a paste-like kneaded material mainly containing an active material is discharged from a nozzle having an opening length substantially the same as the width of the electrode to fill the space of the metal porous body with a strip-shaped metal of the electrode. The compressed part of the porous body is provided at a part of at least one edge with a predetermined interval.

Then, the electrode constructed as described above is cut into a predetermined size, one end of the lead piece is connected to the compression portion of this electrode to form, for example, a positive electrode plate, and a spiral shape composed of this, a negative electrode plate and a separator. The electrode plate group is configured to be an alkaline storage battery.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present onset bright, a portion of at least one of the edges of the strip-shaped metal porous body having continuous space in three dimensions, is pressurized from both sides at a predetermined distance compression After the portion is provided at the center of the thickness, one side of the porous metal body is supported, and while moving this, the opening length is approximately the same as the width of the porous metal body that is brought close to the opposite surface of the porous metal body. A method for manufacturing a battery electrode for discharging a paste-like kneaded material mainly composed of an active material from a nozzle to fill the space inside the metal porous body, wherein the compressed portion of the strip-shaped metal porous body of the electrode is At least a part of one edge is provided with a predetermined interval.

In this case, since the compressed portion of the porous metal body is provided at the center of the thickness, when the active material is filled into this porous metal body from one side, the compressed portion is formed on the surface on the side filled with the active material. Is almost non-porous, the active material is repelled,
It enters the inside of the porous body from the cut end of the recess facing the compression part. Therefore, the filling amount of the porous body facing the concave portion near the compression portion is larger than that of the surrounding portion. On the other hand, the surface opposite to the surface on which the active material is filled is blocked by the compression part so that the active material does not enter the lower side, but the cut part of the recess facing the compression part has a porous body around the recess. The active material with which the space is filled is pushed by the filling pressure of the subsequent active material, and this portion is also filled with the active material. Therefore, in the vicinity of the cut portion of the concave portion facing the compression portion, the filling amount of the active material is increased or decreased to cancel out the variation as a whole, and the active material can be uniformly filled. As a result, the entire electrode can be uniformly filled with the active material.

According to the first aspect of the present invention, most of the space of the metal porous body having the three-dimensionally continuous spaces is filled with the active material, and one surface thereof is connected to the active material filling portion. There is a thin metal part, and a compression part located at the center of the thickness is provided on a part of the edge, and a strip-shaped positive electrode plate to which one end of the lead piece is connected to this compression part and a strip-shaped negative electrode. Plate, and an alkaline storage battery comprising a spiral electrode plate group consisting of a separator, a part of the positive electrode plate edge, a compressed portion is provided in the center of the thickness, the positive electrode plate from the above reason. The active material is uniformly filled. Further, since the alkaline storage battery is constructed using this positive electrode plate, it is possible to reduce variations in the discharge capacity of the battery.

According to a second aspect of the present invention, one end of the lead piece is connected to the surface side of the thin metal portion, which is not filled with the active material, of the compressed portion provided at a part of the edge of the positive electrode plate. By approaching or connecting the lead piece to the thin metal portion, the thin metal portion serves as a conductive portion of the entire positive electrode, so that a larger current can be taken out.

[0016]

EXAMPLES Next, specific examples of the present invention will be described.

To 100 parts by weight of nickel hydroxide, 15 parts by weight of cobalt oxide powder was added and mixed with powder, and water was added to these so that the ratio of the total paste was 25% by weight and kneaded. A material paste was made.

As shown in FIG. 1, a width of 60 mm and a thickness of 3.
0 mm, porosity 98%, average pore diameter 200 μm on one surface of the metal porous body 1 having a three-dimensionally continuous band-shaped space,
A nozzle 2 having a length of 60 mm was arranged opposite to this. A width of 8 mm, a length of 7 mm, and a thickness of 0.2 m were previously applied to a part of the edge of the porous metal body 1 with the same pressure from both front and back surfaces.
The m compressed portion 3 was provided at the center of the thickness. This compression unit 3
It was provided on the edge of the porous metal body 1 every 110 mm.

While supporting one surface (lower surface) of the strip-shaped metal porous body 1 and moving it in the length direction at a speed of 7 m / min, the active material paste is discharged from the nozzle 2 at a rate of 10 g / sec. The space of the porous body 1 was filled. At this time, the distance between the porous metal body 1 and the nozzle 2 was 0.1 mm. The metal porous body 1 filled with the active material paste is pressed to a thickness of 3 mm to 1 mm and cut into a length of 110 mm and a width of 60 mm so that the compression portion 3 is located at the center in the length direction. The produced electrode is referred to as an electrode A according to the embodiment of the present invention, and its sectional view is shown in FIG. As shown in FIG.
Is composed of a portion a filled with an active material and a thin metal portion b not filled with an active material.

For comparison, a portion of the edge of the metal porous body is previously provided with a pressure compression portion on the same side as the active material filling surface and a concave portion facing this, and the active material paste is applied to the metal porous body by the same method as described above. The prepared electrode was used as a comparative example electrode B by filling the body and cutting.

100 electrodes A and B were prepared and the variation in the amount of each active material filled was examined (Table 1).
Got the result.

[0022]

[Table 1]

As is clear from this (Table 1), the variation in the filling amount of the active material is as small as 1.0% in the examples, but the variation in the filling amount is 4.0% in the comparative examples, which is more than that in the examples. 3.0% larger.

In this case, in the comparative example, a pressurizing / compressing portion is provided in advance at a part of the edge of the porous metal body on the same side as the filling surface, and when the space of the porous metal body is filled with the active material. ,
This compressed portion is almost non-porous and cannot be filled with the active material, so that it will bounce off and escape to the outside. As a result, the amount of the active material filled in the vicinity of the recess facing the compressed portion of the metal porous body is smaller than that in the surroundings, so that the amount of the active material filled in the electrode as a whole varies.

In the embodiment, a part of the edge of the porous metal body is preliminarily pressed from both front and back sides to provide a compressed portion at the center of the thickness. Therefore, when the space portion of the porous metal body is filled with the active material, On the surface of the side where the active material is filled, the compressed portion is substantially non-porous, and the active material cannot be filled in the compressed portion, and is repelled and enters the porous body through the cut end of the recess facing the compressed portion. Therefore, the filling amount of the active material in the vicinity of the compressed portion in the upper half of the porous body is larger than that in the surrounding area. However, on the other hand, on the surface opposite to the surface on which the active material is filled, the compressed portion serves as a barrier to bounce off the active material, and the amount of the active material filled in the vicinity of the compressed portion in the lower half of the thickness of the porous body is smaller than the surrounding area. But,
At the cut end of the recess facing the compression part, in the vicinity of the compression part pressed by the filling pressure from the surrounding area, the filling amount of the active material between the filling surface (upper half) and the opposite surface (lower half) increases or decreases. Since the variations cancel out each other, as a result, the active material is filled in a nearly uniform state, and the amount of the active material filled in the electrodes is reduced.

Next, the electrode A produced above was used as the positive electrode 4A, and the compression portion 3 had a width of 3 mm, a length of 10 mm and a thickness of 0.15.
One end of the mm lead piece 5 was spot-welded to the surface side of the thin metal portion b of the compression portion 3 not filled with the active material. A front view of the positive electrode 4A is shown in FIG. 3, and a sectional view thereof is shown in FIG.

The positive electrode 4A, the hydrogen storage alloy negative electrode 6, and a polar plate group formed by spirally winding a polypropylene separator 7 between the positive electrode 4A and the hydrogen storage alloy negative electrode 6 are inserted into a metal battery case 8 for alkaline electrolysis. After injecting a predetermined amount of the liquid, the upper part of the case 8 is sealed with a sealing plate 9 which also serves as a positive electrode terminal, and a long A size (outer diameter 16.5 mm, height 66.0 mm) nickel of the embodiment of the present invention is used. Ten hydrogen storage batteries (nominal capacity 3300 mAh) were constructed. A configuration diagram of this battery is shown in FIG.

For the purpose of the comparative example, the electrode B of the comparative example was replaced by the positive electrode 4
Ten batteries having the same structure as that of the embodiment of the present invention except that the battery was used as B were formed as comparative batteries.

FIG. 6 shows an average discharge voltage curve when each of the 10 batteries of Examples of the present invention and Comparative Example was discharged at a battery voltage of 1.0 V at a current value of 3300 mA (Table 2).
Shows the variation in discharge capacity of each battery.

[0030]

[Table 2]

As shown in FIG. 6, the average discharge capacity of the battery of the example was 3300 mAh, and that of the battery of the comparative example was 320.
It is 0 mAh, which means that the discharge capacity of the example is larger than that of the comparative example. Further, as shown in (Table 2), it is understood that the discharge capacity variation of the example is 4.2% smaller than that of the comparative example.

This is because the battery of the embodiment uses the positive electrode 4A having a small variation in the active material filling amount, and therefore the variation in discharge capacity is as small as 1.1% as shown in (Table 2).
The average discharge capacity is 3300 mAh, which is the same as the nominal capacity. However, in the comparative example, since the positive electrode 4B was used, the vicinity of the recess facing the compression part of the positive electrode 4B to which the lead piece involved in the discharge of the battery was particularly connected was used. However, since the filling amount of the active material is smaller than that of the peripheral portion and the variation is large, the average discharge capacity of the battery of the comparative example is 100 mAh lower than the nominal capacity, and the variation is 5.3%. It is bigger than that.

[0033]

As described above, according to the method for producing an electrode of the present invention, it is possible to construct an electrode in which a metal porous body having a three-dimensionally continuous space portion is uniformly filled with an active material, and the electrode is used. By configuring the alkaline storage battery as described above, it is possible to provide an alkaline storage battery with less variation in discharge capacity.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which an electrode is filled with an active material according to an embodiment of the present invention.

FIG. 2 is a sectional view of the electrode.

FIG. 3 is a front view of a positive electrode obtained by welding one end of the lead piece.

FIG. 4 is a sectional view of the positive electrode.

FIG. 5 is a configuration diagram of the nickel-hydrogen storage battery.

FIG. 6 is a diagram showing an average discharge curve of the battery.

[Explanation of symbols]

1 Porous metal with three-dimensionally continuous space 2 nozzles 3 Compressor 4 positive electrode 5 lead pieces 6 Hydrogen storage alloy negative electrode 7 separator 8 battery case 9 Seal plate

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-9-82332 (JP, A) JP-A-9-27342 (JP, A) JP-A-52-74841 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01M 2/26 H01M 4/80

Claims (2)

(57) [Claims] 1. A large part of the space of a metal porous body having a three-dimensionally continuous space is filled with an active material, and one surface thereof has a thin metal part connected to the active material filled portion,
A compressed portion located at the center of the thickness is provided at a part of the edge, and is composed of a strip-shaped positive electrode plate having one end of the lead piece connected to this compressed portion, a strip-shaped negative electrode plate, and a separator. An alkaline storage battery equipped with a spiral electrode plate group. 2. A surface side of a thin metal portion which is not filled with an active material, of a compressed portion provided on a part of an edge of the positive electrode plate,
The alkaline storage battery according to claim 3, wherein one end of the lead piece is connected.