JPS5864762A - Lead accumulator - Google Patents

Abstract

PURPOSE:To save a quantity of used lead and obtain a light grid body with good productivity by a method wherein a collector and neighboring grid bones in the surface of a grid structure are coated with lead, while the uncoated grid bones are notched to communicate through grid apertures. CONSTITUTION:For preventing an acting substance from falling off, a part of rectangular grid apertures surrounded by bones of a synthetic resin, for instance, a part of a collector 2 and its neighboring grid bones 3 of a grid structure, while being notched in the protruded shape so that synthetic resin bones 3a may face each other, are so made as to be coated with a film of lead or of a lead alloy. Thereby a quantity of used lead can be saved, manufacture is simplified to be able to improve productivity as well as life performance of a plate can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the grid used in lead-acid batteries, and its purpose is to reduce the amount of lead used and to create a grid that is extremely lightweight compared to conventional grids. Our objective is to provide lead-acid batteries that are highly productive, inexpensive, and have a long service life.

Recently, there has been a strong need to reduce the weight of lead-acid batteries in order to improve fuel efficiency in automobiles, increase mileage in electric vehicles, and make them easier to carry in portable devices.

However, the grid of lead-acid batteries is usually manufactured by casting a lead alloy. The specific gravity of pure lead is heavy at 11.3, and efforts were made to make the grid thinner to make it lighter.
Not only is it difficult to cast to a thickness of 1M or less, but it may also be deformed during the subsequent paste filling process, etc.
Due to problems such as curving during handling, there were certain limits to reducing the weight of cast grids.

Therefore, compared to conventional lead alloys, it has been considered to partially use synthetic resins whose specific gravity is the fishing part instead of lead alloys, and use lead alloys only in the parts that require conductivity to retain the active substance. Various so-called lead alloy-synthetic resin composite lattice bodies have been considered in which a synthetic resin body is used for the sliding portion.

For example, as seen in Japanese Patent Application Laid-Open No. 50-8037,
Cast the parts that require conductivity from lead alloy. A lead alloy-synthetic resin composite lattice body has been proposed in which the cast lattice piece is then inserted into a synthetic resin mold and the synthetic resin is poured in to mold the part that holds the active substance out of synthetic resin. There is.

Further, Japanese Utility Model Publication No. 43-3535 proposes a lead alloy-synthetic resin composite lattice body in which a synthetic resin lattice body and a lead alloy perforated plate are laminated and bonded.

However, all of these have complicated manufacturing processes, and the conductive lead alloy parts are thin bones or thin plates, so they are easily deformed and difficult to handle. Therefore, although it is possible to reduce the weight to some extent, it has the drawback of poor productivity and not being suitable for mass production. Therefore, a method was devised in which a lattice structure made of synthetic resin was immersed in molten lead, then quickly pulled up and coated with a thin lead film.

This production method is simple, produces good raw wheat quality, and is easy to produce continuously. At that time, the thickness of the lead thin film is 150 to 50
Since the entire surface of the synthetic resin lattice structure was coated with 0μ, it was difficult to manufacture an ultra-lightweight lattice structure.

The lattice body used in the lead-acid battery of the present invention can be prepared by immersing a part of the synthetic resin lattice structure in molten lead or lead alloy and then quickly pulling it up, or by pouring molten lead or lead alloy over the synthetic resin lattice structure. At least the current collector and the grid bones in the vicinity of the current collector of the synthetic resin lattice structure are coated with a thin film of lead or lead alloy by hanging or the like.

The lattice body used in the lead-acid battery of the present invention will be described below based on Examples. A grid body 1 made of polypropylene having the same shape as the conventional cast grid shown in FIG. The polypropylene grid was immersed for 0.3 seconds, then pulled out and cooled with cold air or cold water to coat the polypropylene grid with a thin film of pure lead approximately 200 microns thick.

FIG. 2 shows the lead-synthetic resin composite lattice body 4.

However, this composite lattice 4 is a paste-like structure filled on top of the synthetic resin, since the usually rectangular lattice surrounded only by the synthetic resin bones 3' has an electrical path cut off from the current collector 2. The conductivity of the active substance must be utilized. In addition, although the active substance has adhesive strength due to oxidation of the surface of the lead alloy thin film, it not only has no adhesive strength to the synthetic resin, but also cracks occur due to the difference in coefficient of thermal expansion. The inventors developed a usually rectangular grid surrounded by synthetic resin ribs as a method to fully utilize the conductivity of the active substance, increase the contact area between the active substance and the synthetic resin body, and prevent the active substance from falling off. They discovered a way to cut out a part of the synthetic resin bone of the eye. The shape of the lead-synthetic resin composite lattice at that time is as follows:
As shown in FIG. 3, there is a shape in which the synthetic resin bones 3a are alternately cut out and protruding shapes, and as shown in FIG. 4, there is a shape in which the synthetic resin bones 3a are cut out so as to face each other.

To explain the principle of the grid body of the present invention, when a polypropylene grid is immersed in molten lead, the lead around the polypropylene is instantly absorbed by the polypropylene and solidifies. By then pulling quickly, a thin film of lead is formed.

Therefore, if the polypropylene is immersed for a long period of time, not only will the polypropylene melt, but the once solidified lead alloy will rise above its melting point due to the surrounding molten lead and will melt again, making it impossible to attach a thin lead film. Also, in an extremely short period of time, the lead around the synthetic resin may solidify. The test result is 0
．． The conditions of immersion for 1 to 1 second were favorable. Also, if the molten lead temperature is too high, it may not be possible to form a thin lead film as in the case of immersion for a long time. The test results showed that the molten lead temperature was 327 to 350°C. Although pure lead was used in the examples, the molten lead does not have to be pure lead, and may be a lead-antimony alloy or a lead-tin alloy.In this case, the melting point is lower than that of pure lead, so It was found that thin films can be formed at low temperatures. Furthermore, the same effect as immersion was observed even when the molten lead alloy was poured from above the synthetic resin. The material of the acid-resistant synthetic resin to which the thin lead film is attached is polypropylene in the embodiment, but it may also be a thermoplastic or thermosetting resin such as polyethylene, polyvinyl chloride, phenol resin, etc. Furthermore, its shape may be a lattice-like circular punched body, an expanded diamond shape, or the like.

A feature of the lead-acid battery of the present invention is that it becomes a lead alloy-synthetic resin composite lattice by simply covering the current collector of the synthetic resin lattice structure and a portion of the lattice bones in the vicinity with a thin film of lead or lead alloy. , the weight can be significantly reduced compared to the conventional lead alloy-synthetic resin composite grid.

In addition, since the punch part of the synthetic resin lattice structure that is not coated with lead alloy is cut out, the conductivity and adhesion between the active substance and the grid are good, and the active substance does not easily fall off, making battery assembly easy. In addition, the grid and the active substance do not separate even when the battery is vibrated or dropped, so the life of the electrode plate can be improved. Furthermore, the manufacturing method is simple and has good productivity, making it suitable for continuous manufacturing methods.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a synthetic resin lattice structure, and FIG. 2 is a diagram showing a lattice body in which a current collector of the present invention and a part of the lattice bones in the vicinity thereof are covered with a thin film of lead or lead alloy. FIGS. 3 and 4 are diagrams showing a synthetic resin lattice structure according to an embodiment of the present invention, in which lattice bones not covered with lead or lead alloy are missing. 1... Synthetic resin lattice structure, 2... Current collector, 3... Lattice ribs, 3a... Notched lattice ribs. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 2 Figure 4

Claims (2)

[Claims] (1) A lead-acid battery comprising a lattice structure in which at least the current collector and the lattice bones in the vicinity of the surface of the lattice structure made of an acid-resistant synthetic resin are coated with lead or a lead alloy. (2) The lead-acid battery according to claim 1, wherein the lattice bones of the lattice structure that are not covered with lead or lead alloy are cut out to communicate the lattice meshes.