JP2690344B2 - Method for manufacturing paste electrode for alkaline storage battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a paste electrode for an alkaline storage battery.

[Conventional Technology and Problems] Conventionally, electrodes used in alkaline storage batteries such as nickel-cadmium storage batteries have been manufactured by the following two methods.

. A slurry in which a thickening agent such as carboxymethyl cellulose is mixed with carbonyl nickel is applied to a perforated steel plate such as nickel-plated punch bametal, dried, and then sintered to produce a porous nickel sintered substrate. A method of manufacturing electrodes by a so-called sintering method in which a substrate is impregnated with nickel hydroxide or cadmium hydroxide.

. An active material such as nickel hydroxide or cadmium oxide powder is kneaded together with various additives and thickeners to prepare a paste-like material, and the paste-like material is three-dimensionally formed, for example, on foam metal or a sintered metal fiber substrate. A method of manufacturing an electrode by a so-called non-sintering method in which a conductive core having a structure is directly filled.

The above-mentioned non-sintering method has the advantage that the manufacturing process can be simplified, the manufacturing cost can be reduced, and the capacity can be increased as compared with the above-mentioned sintering method.
Currently, development is actively underway. However, unlike the electrode manufactured by the above method, the electrode manufactured by the above method does not have a strong portion that serves as a current collector in the conductive core having a three-dimensional structure. It was difficult to apply the current collection method to the so-called tabless method, which is a current collection method.

As a method for solving such a problem, the following proposals have been made. One method is to form a plain portion to be a current collecting portion on a conductive core having a three-dimensional structure, further fill the core with a paste containing an active material, and after drying,
This is a method of scraping off a dry paste-like material on the plain portion with a rotating brush or scraper and welding a ribbon-shaped metal piece onto the plain portion. Another method is to fill a conductive core having a three-dimensional structure with a paste containing an active material, and after drying, crush the paste in the core using a needle-shaped protrusion or a high-pressure water stream. After the removal, the U-shaped metal piece or the ribbon-shaped metal piece is welded. Further, another method is to form a plain part to be a current collecting part on a conductive core having a three-dimensional structure, and then stick an adhesive tape on the plain part, and further to form a paste containing an active material. This is a method in which the core is filled, dried, and then the adhesive tape is peeled off from the plain part, and a ribbon-shaped metal piece is welded to the plain part.

However, the paste-like material remains on the plain portion by the method of scraping the paste-like material on the plain portion with a rotary brush or the method of crushing and removing the paste-like material in the conductive core with a high-pressure water stream or the like. Therefore, when welding a ribbon-shaped metal piece on the plain portion for the purpose of reinforcing and collecting efficiency, a sparking phenomenon in which sparks due to the residual paste-like material are scattered,
Splash occurs, welding strength decreases,
As a result, there is a possibility of causing an internal short circuit when incorporated into a battery. In fact, when the surface of the uncoated part after removing the paste-like material by the above two methods is observed with an optical microscope, the paste-like material is rubbed or entangled with the conductive core having a three-dimensional structure. Existed in a state. In particular, the removal method using a high-pressure water stream has a problem that the conductive core itself having a three-dimensional structure collapses. Further, the method of sticking the adhesive tape on the plain portion has a problem that the manufacturing process is complicated and mass productivity is poor.

The present invention has been made in order to solve the above-mentioned conventional problems, in which the paste-like material in the uncoated portion of the conductive core having a three-dimensional structure is removed as much as possible, and when welding a ribbon-shaped metal piece or the like. An object of the present invention is to provide a method of manufacturing a paste electrode for a high-performance alkaline storage battery, which is capable of rapid charging / discharging and can achieve reduction of splash and improvement of welding strength.

[Means for Solving the Problems] According to the present invention, a method for producing a paste electrode for an alkaline storage battery, in which a conductive core having a three-dimensional structure is filled with a paste material containing an active material, the conductive core Forming a sheet metal-like plain portion by compressing a part of the above, a step of filling the electrically conductive core with the paste-like material, and the paste-like material on the plain portion while the paste-like material has fluidity. An alkaline storage battery, comprising a step of sucking and removing the paste-like material on the plain portion while dropping a liquid compatible with a solvent used when the paste-like material is prepared into the paste-like material. Provided is a method of manufacturing a paste electrode for a car.

Further, according to the present invention, in a method for manufacturing a paste electrode for an alkaline storage battery in which a conductive core having a three-dimensional structure is filled with a paste material containing an active material, a part of the conductive core is compressed. A step of forming a sheet metal-like plain part, a step of filling the conductive core with the paste-like material, and a step of sucking the paste-like material on the plain part while the paste-like material has fluidity And a step of sucking and removing the residual paste-like material while dropping a liquid having compatibility with the solvent used when adjusting the paste-like material to the paste-like material remaining on the plain portion. A method for manufacturing a paste electrode for an alkaline storage battery is provided.

As the compression means for forming the uncoated portion on the conductive core, for example, a roller pressing method or the like can be adopted.

Examples of the conductive core having a three-dimensional structure include foam metal, a sintered metal fiber substrate, and a metal plated fiber substrate.

Examples of the pasty material include a positive electrode active material such as nickel hydroxide and carboxymethyl cellulose, methyl cellulose, a positive electrode pasty material composed of a binder such as sodium polyacrylate and a solvent such as water, and cadmium oxide. An example of the paste material for a negative electrode includes a composition of a negative electrode active material, a binder such as polyvinyl alcohol, and a solvent such as ethylene glycol. In addition,
If necessary, cobalt hydroxide, particularly β-Co (OH) ₂ , may be added to the positive electrode paste in order to increase the utilization rate.

As the liquid, for example, when the positive electrode paste material using water as a solvent is used as described above, water is used, and when the negative electrode paste material using ethylene glycol as a solvent is used, alcohol or ethylene glycol is used.

[Operation] In a method of forming a plain portion on a conductive core having a three-dimensional structure by a roller pressing method or the like, filling a paste-like material containing an active material, and drying and then scraping off with a rotating brush or the like, It is not possible to completely remove the paste-like material on the plain portion because the paste-like material rubs into the core due to the unevenness that is always present in the plain portion. On the other hand, in the present invention, a conductive core having a three-dimensional structure is filled with a paste-like material containing an active material, and the paste-like material on the plain portion is sucked while the paste-like material has fluidity. By doing so, the paste-like material on the plain portion can be almost completely removed. In fact, when the uncoated portion after removing the paste-like material by such a method is observed with an optical microscope, the residual paste-like material observed by the scraping method is hardly recognized.

On the other hand, if a high-viscosity paste-like material is used, the paste-like material on the plain portion may remain after a single suction operation. In such a case, suction is performed while dropping a liquid compatible with the solvent used when adjusting the paste-like material onto the paste-like material on the plain portion, or by sucking the paste-like material on the plain portion. After that, while dropping a liquid having compatibility with the solvent used when preparing the paste-like material to the paste-like material remaining on the plain portion, by suction removing this residual paste-like material, Even if there is a highly viscous paste, it can be almost completely removed.

Therefore, when a ribbon-shaped metal piece or the like is welded on the uncoated portion after removing the paste-like material by the above method, a high-performance alkali corresponding to rapid charge / discharge that can achieve reduction of splash and improvement of welding strength. A storage battery paste electrode can be manufactured.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Reference Example First, nickel hydroxide was the main component, cobalt hydroxide and carboxymethyl cellulose were added thereto, and distilled water as a solvent was added and kneaded to prepare a paste.
Also, a part of the sintered nickel fiber substrate, which is a conductive core having a three-dimensional structure, was compressed by a roller press to form a plain part.

Then, after filling the substrate with the paste-like material,
While the paste-like material has fluidity, a suction nozzle 2 connected to a suction pump (not shown) is pressed onto the plain portion 1 as shown in FIG. 1 to suck the paste-like material 3 on the plain portion 1. Removed. Then, the paste-like material filled in the sintered nickel fiber substrate was dried.

Example 1 A paste-like material having a viscosity 1.5 times that of the paste-like material of the reference example was prepared by reducing the amount of distilled water added. Subsequently, as in Example 1, the paste-like material was filled into a sintered nickel fiber substrate on which a plain portion was previously formed. Subsequently, while the paste-like material has fluidity, as shown in FIG. 2, while dripping distilled water from the dripping nozzle 4 onto the uncoated portion 1, the suction nozzle 2 connected to a suction pump (not shown) is pressed against it. Then, the paste-like material 3 on which the distilled water was dripped on the plain portion 1 was sucked and removed. Then, the paste-like material filled in the sintered nickel fiber substrate was dried.

Example 2 A paste-like material having a viscosity 1.5 times lower than that of the paste-like material of the reference example was prepared. Subsequently, as in Example 1, the paste-like material was filled into a sintered nickel fiber substrate on which a plain portion was previously formed. Subsequently, while the paste-like material has fluidity, as shown in FIG. 3, a first suction nozzle 21 connected to a suction pump (not shown) is pressed against the plain portion ₁ to press the plain portion 1 on the plain portion 1. The paste 3 was sucked. Further, the first suction nozzle
While dropping distilled water from dropping nozzle 4 onto the uncoated portion 1 which is sucked by 2 _1, pressing a second suction nozzle 2 ₂ connected to a suction pump, not shown, dropping distilled water on the inorganic fabric part 1 The remaining paste-like material 3'was removed by suction. Then, the paste-like material filled in the sintered nickel fiber substrate was dried.

Comparative Example Like the reference example, the paste-like material was filled in the sintered nickel fiber substrate on which the uncoated portion was previously formed, and then the paste-like material was dried. Subsequently, as shown in FIG. 4, the paste-like material 12 on the uncoated portion 11 was scraped off by the rotating brush 13, and the scraped paste-like material was discharged by the suction duct 14.

Then, in the present Examples 1 to 2, the paste-like material in the reference example and the comparative example, the uncoated portion of the paste-like material is overlapped with the nickel ribbon so as not to abut the filled portion of the paste-like material, and 100 spot weldings are performed. When the number of splashes generated at that time was examined, the results shown in FIG. 5 were obtained.

As is apparent from FIG. 5, in Examples 1 and 2, the number of occurrences of splash due to the paste-like material remaining on the plain portion was determined in spite of the removal of the highly viscous paste. It can be seen that it can be significantly reduced compared to the comparative example.

[Effects of the Invention] As described in detail above, according to the present invention, the paste-like material in the uncoated portion of the conductive core having a three-dimensional structure is removed as much as possible, and the splash in the welding of the ribbon-shaped metal piece or the like It is possible to provide a method of manufacturing a high-performance paste electrode for an alkaline storage battery, which is compatible with rapid charging / discharging and can achieve reduction and improvement of welding strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a paste-like substance suction removal process in a reference example, and FIG. 2 is a schematic diagram showing a paste-like substance suction removal process in Example 1 of the present invention. FIG. 3 is a schematic diagram showing a suction-like removal process of a paste-like material in Example 2 of the present invention, FIG. 4 is a schematic diagram showing a suction-like removal process of a paste-like material in a comparative example, and FIG. FIG. 4 is a characteristic diagram showing the number of occurrences of splash in the reference example and the comparative example. 1 ...... uncoated region, 2,2 _1, 2 ₂ ...... suction nozzle, 3 ...... paste-like product, 4 ...... dropping nozzle.

Front page continuation (72) Inventor Koji Isawa 3-4-10 Minami-Shinagawa, Shinagawa-ku, Tokyo TOSHIBA Battery Co., Ltd. (72) Inventor Katsuyuki Qin 3-4-10 Minami-Shinagawa, Shinagawa-ku, Tokyo TOSHIBA Battery Co., Ltd. (72) Inventor Kunihiko Sasaki 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Inside Toshiba Research Laboratory Co., Ltd. (56) Reference JP-A-55-14685 (JP, A)

Claims (2)

(57) [Claims] 1. A method of manufacturing a paste electrode for an alkaline storage battery, in which a conductive core having a three-dimensional structure is filled with a paste containing an active material, wherein a part of the conductive core is compressed to form a sheet metal. Forming a plain portion, filling the conductive core with the paste-like material, and adjusting the paste-like material to the paste-like material on the plain portion while the paste-like material has fluidity A step of sucking and removing the paste-like material on the uncoated portion while dropping a liquid compatible with the solvent used at the time of manufacturing. 2. A method of manufacturing a paste electrode for an alkaline storage battery in which a conductive core having a three-dimensional structure is filled with a paste containing an active material, wherein a part of the conductive core is compressed to form a sheet metal. Forming a plain portion, filling the conductive core with the paste-like material, sucking the paste-like material on the plain portion while the paste-like material has fluidity, A step of sucking and removing the residual paste-like material while dropping a liquid having compatibility with a solvent used when adjusting the paste-like material to the paste-like material remaining on the plain part. A method of manufacturing a paste electrode for an alkaline storage battery.