JP3489380B2 - Electrode for cylindrical battery and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spirally wound electrode for a cylindrical battery, and more particularly to facilitating the treatment of the beginning and end portions of the electrode during winding.

[0002]

2. Description of the Related Art Battery electrodes are roughly classified into paste type electrodes, sintered type electrodes, and pocket type electrodes. In recent years, as an alkaline storage battery, a paste-type electrode in which a sponge-like metal porous substrate having a three-dimensional structure skeleton made of nickel is filled with a paste-like kneaded material has been put into practical use and widely used. Since these porous metal substrates have a porosity of about 95% and the pore diameters of the pores reach up to several hundreds of μm, it is possible to directly fill the paste-like active material or the active material powder with a simple construction method. The feature is that the electrode can be manufactured by.

Conventionally, as a concrete method of filling the porous metal substrate with the active material, a method of filling the paste-like active material with vibration, a method of kneading the paste-like active material with a doctor knife or the like, a paste-like method A method in which the active material is sprayed from a nozzle and sprayed onto the porous metal substrate, and a constant amount of paste-like active material is continuously discharged from the nozzle tip,
There is a nozzle die coating method in which a metal porous substrate that has run at a constant speed is coated.

Of these methods, the nozzle die coating method is excellent for uniformly filling the metal porous substrate with the active material, and FIG. 1 is a perspective view showing the filled state of the active material. In the figure, reference numeral 1 denotes a sponge-like porous metal substrate made of strip-shaped nickel, which is moving in the direction of the arrow. The paste-like active material is discharged from the nozzle 2 onto the base 1 to obtain the paste coating portion 3.

[0005]

The electrode for a battery using such a sponge-like porous metal substrate takes advantage of its high porosity and is filled with an active material inside and on the surface of the porous metal substrate. Packing with a higher capacity density is possible compared to the type, but a higher capacity is demanded from a practical point of view, and various additives and construction methods are being studied.

The nozzle die coating method is a method suitable for efficiently and uniformly filling a porous metal substrate with a constant amount of an active material. When used as a battery, the capacity can be increased, but the nozzle die coating method is used. Since the filling amount of the paste to be made is easy to make uniform and it is difficult to give a change, both ends of the winding start and the winding end of the electrode have the same thickness as the central part, and when spirally wound as an electrode group, Between the start of winding and between the case and the end of winding, a residual space unrelated to the capacitance is formed in proportion to the thickness of the electrode.

The present invention solves the above-mentioned problems, and provides a cylindrical battery electrode that can be wound in a spiral shape with very little remaining space at the beginning and end of winding, and a method for producing the same. With the goal.

[0008]

In order to achieve the above object, the present invention provides a cylindrical battery electrode in which the active material is filled in the pores of a strip-shaped metal porous substrate having a three-dimensional network skeleton. Both ends of the electrode in the longitudinal direction are thinner and softer than the central part.

[0009]

Detailed Description of the Invention The present onset bright, which has an electrode of the content, when the wound the electrode spirally winding start portion of the electrode was excellent in soft since bendability thin As a result, the diameter at the beginning of winding can be reduced. From this, it is possible to reduce the space that is not involved in the electric capacitance generated between the winding start portion and the case and the winding end portion, and increase the filling volume of the electrode group in the case by the amount that the remaining space decreases. Thus, it is possible to increase the capacity of the cylindrical battery.

The present invention has a shape in which both ends of the above-mentioned electrode in the longitudinal direction gradually become thinner from the root to the tip, and such a shape, for example, a sequential step If you make it thinner on one side or thinner on one side continuously, the diameter at the beginning of winding can be made smaller and the end of winding becomes a gentle slope, so it becomes a case. The remaining space generated during the end of winding can be reduced.

Further, if the shape of both end portions of the electrode in the longitudinal direction is such that both sides are continuously thinned from the root portion to the tip portion, both end portions will have a gentle slope, so that the winding start portion Also, the remaining space between the case and the end of winding can be minimized, and since the shape of both ends is the same, there is no need to distinguish between the start of winding, the end of winding, and the front and back, which is extremely convenient for assembly of the electrode group. Is.

According to the first aspect of the present invention, a paste having an active material as a main component is formed in pores formed between skeletons while running a strip-shaped metal porous substrate having a skeleton having a three-dimensional network structure in the length direction thereof. A method for manufacturing a battery electrode in which the paste is filled using a nozzle having a discharge gap at both ends of the paste discharge part narrower than that in the central part when the paste is filled, and then pressed by a press machine, The degree of pressurization is based on the manufacturing method of the cylindrical battery electrode in which the compression ratio of both ends is made larger than that of the center part of the electrode, and both ends of the electrode in the longitudinal direction are thinner than the center part. It is a manufacturing method that can be softened.

According to a second aspect of the present invention, in the method for producing an electrode according to the fourth aspect, the press machine uses a pair of rollers having both ends whose diameter is larger than that of the central part to produce the electrode. This makes it possible to provide an electrode in which both ends in the longitudinal direction of the electrode are continuously thinned from both sides from the root to the tip.

[0014]

【Example】

(Example 1) To 100 parts by weight of nickel hydroxide, 10 parts by weight of cobalt oxide powder was added and powder-mixed, and water was added thereto as a dispersion medium so that the specific gravity of the whole paste was 25% by weight. The mixture was kneaded to obtain a paste-like active material.

As shown in FIG. 1, a width of 60 mm and a thickness of 3 m
A nozzle 2 having a length of 60 mm was fixedly disposed on one surface of a sponge-like metal porous substrate 1 made of nickel and having an average pore diameter of 200 μm and having a size specification of m and a porosity of 98%. As shown in FIG. 2, the nozzle 2 used was one in which the paste discharge part 4A of the nozzle 2 had an opening width at both ends narrower than that at the central part.

While supporting one surface (lower surface) of this porous metal 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. Was filled in the hole.

This was pressed by a smooth roller press to form an electrode whose both ends were thinner than the central part. Then, this was cut into a predetermined size to obtain an electrode in Example 1 of the present invention. The schematic diagram is shown in FIG.

For comparison, the nozzle 2 as shown in FIG.
Using the nozzle 2 having the same central portion as the both end portions of the discharge portion 4B of
An electrode manufactured by the same method as in Example 1 of the present invention was used as a comparative example electrode except for the above, and a schematic diagram thereof is shown in FIG.

A lead piece was spot-welded to a part of the edge of the electrode of Example 1 to produce a positive electrode plate 5, and a spiral electrode composed of this, a nonwoven fabric separator 6 of polypropylene and a hydrogen storage alloy negative electrode plate 7. A group was prepared, this was inserted into the case 8, a predetermined electrolytic solution was injected, and a cylindrical nickel-hydrogen storage battery of 4/5 A size was configured to be a battery in Example 1 of the present invention. A battery having the same structure as that of Example 1 except that the electrode of the comparative example was used was used as the battery of the comparative example.

FIG. 6 is a partial cross-sectional view of the battery in Example 1 cut in the lateral direction. Since both ends in the longitudinal direction of the electrode are thinner and softer than those in the central part, the diameter at the beginning of winding is set. Can be made smaller, and the winding end portion becomes thinner toward the tip end portion in sequence, so that the remaining space 9 is reduced. As a result, the remaining space 9 that does not contribute to the electric capacity of the battery can be reduced.

FIG. 7 is a partial cross-sectional view of the battery of the comparative example cut in the lateral direction.
Since the thickness is the same as that of the central portion, the diameter at the beginning of winding becomes larger and the thickness at the end of winding becomes thicker than that of the embodiment, and the remaining space 9 increases accordingly.

Therefore, by using the electrode of Example 1 in the cylindrical battery, the volume of the electrode group filled in the case can be increased more than that of the electrode of Comparative Example using the electrode, and as a result, the battery can be made higher. Capacity can be increased.

Example 2 The same band-shaped sponge-like metal porous substrate 1 as in Example 1 was used, the active material paste had the same formulation, and the paste-like active substance was filled in the metal porous substrate 1 using the nozzle 2. As shown in FIG. 8, a pair of press rollers 10 whose both ends have a larger diameter than that of the central part.
It was pressed using a roller press machine having a. Then, this was cut into a predetermined size to obtain an electrode in Example 2 of the present invention. The schematic diagram is shown in FIG.

The shape of both ends in the longitudinal direction of the electrode in Example 2 is such that it becomes thinner continuously from the upper and lower surfaces as it goes from the root to the tip, and both ends of the electrode in Example 1 are further reduced. Since the part has a gentle slope, the remaining space 9 generated between the winding start part and the case and the winding end part can be minimized. As a result, the filling volume of the electrode group in the case can be increased most,
It is possible to further increase the capacity of the battery. Moreover, since the shape of both ends of this electrode is the same, it is not necessary to distinguish the winding start portion, the winding end portion, and the front and back sides, which is extremely convenient for the assembly of the electrode group.

[0025]

As described above, according to the present invention, in the cylindrical battery electrode in which the active material is filled in the pores of the strip-shaped metal porous substrate having the skeleton of the three-dimensional network structure, the longitudinal direction of the electrode Both ends of the are thinner than the central part,
Further, by providing it softly, when the electrode is wound in a spiral shape, the winding start portion of the electrode has excellent bendability, and the winding start diameter can be reduced. From this, it is possible to reduce the space that is not involved in the electric capacitance generated between the winding start portion and the case and the winding end portion, and increase the filling volume of the electrode group in the case by the amount that the remaining space decreases. Thus, it is possible to increase the capacity of the cylindrical battery.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a band-shaped sponge-like metal porous body is filled with an active material.

FIG. 2 is a bottom view of a nozzle used for manufacturing an electrode in Example 1 of the present invention.

FIG. 3 is a schematic diagram of the electrode

FIG. 4 is a bottom view of a nozzle used for manufacturing an electrode in a comparative example.

FIG. 5 is a schematic diagram of the electrode

FIG. 6 is a partial cross-sectional view of the battery in Example 1.

FIG. 7 is a partial cross-sectional view of a battery in a comparative example.

FIG. 8 is a diagram showing a pair of press rollers in Example 2.

FIG. 9 is a schematic diagram of the electrode

[Explanation of symbols]

1 Band-shaped sponge-like porous metal substrate 2 nozzles 3 Paste coating part 4 Paste dispenser 5 Positive plate 6 separator 7 Negative plate 8 cases 9 remaining space 10 Press rollers

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-283069 (JP, A) JP-A-6-20718 (JP, A) JP-A-60-243967 (JP, A) Actual development Sho-51- 66727 (JP, U) Actually developed 53-160720 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 4/04 H01M 4/28 H01M 4/30

Claims (2)

(57) [Claims] 1. When filling a band-shaped metal porous substrate having a skeleton with a three-dimensional network structure in the length direction while filling the pores formed between the skeletons with a paste mainly containing an active material, A method of manufacturing a battery electrode in which the paste is filled using a nozzle having a discharge gap at both ends of the paste discharge part narrower than that in the central part, and then pressed by a press machine, and the degree of pressurization is A method for manufacturing an electrode for a cylindrical battery, in which the compressibility at both ends is greater than that at the center of the electrode. 2. The method for manufacturing a battery electrode according to claim 4, wherein the pressing machine has a pair of rollers each having both ends having a diameter larger than that of the central part.