JPH064536Y2 - Lead acid battery - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a lead storage battery, and relates to a configuration of an electrode plate and a battery case housing the same.

(B) Conventional technology As a conventional example of a small sealed lead-acid battery to which the present invention is directed, the "method for producing a lead-acid battery" disclosed in Japanese Patent Laid-Open No. 60-79669 is cited, and the conventional technology will be explained accordingly To do.

The technology disclosed in the above publication is a lead-acid battery in which a plate-shaped current collector made of lead or a lead alloy is arranged in a resin battery case, and a pole plate is formed in close contact with the current collector. A constant amount of a kneaded material of a slurry-like active material powder and a liquid is injected onto the surface of the current collector, and the weight of the kneaded material or microvibration is applied to the electrode plate horizontal to the current collector surface. A layer is formed, and a step portion having a height equal to or smaller than the thickness dimension of the dried kneaded body is formed on the inner wall of the battery case surrounding the current collector. With this technology, it was possible to reduce the capacity variation by controlling the amount of the slurry-like active material injected, and to greatly improve the environment of the electrode plate manufacturing process by preventing the scattering of lead powder etc., and to reduce the size and simplification of the manufacturing equipment. However, when mass-producing conventional lead-acid batteries, when the electrode plate layer of the active material is formed on the surface of the current collector, the spreading speed is slow only by the weight of the slurry-like mixture, and the mechanical vibration that is the point of the above publication Alternatively, it is necessary to incline the battery case itself. The height of the liquid level of the slurry-like mixture fluctuates due to this mechanical vibration and the inclination of the battery container itself, and the mixture rides on the stepped portion located around the current collector, and the thickness of the electrode plate layer that is completed is required. There is a problem in that the rate of defective products that do not reach a sufficient amount increases.

(C) Problems to be solved by the device The problem to be solved by the present invention is to form the electrode plate by injecting the slurry-like active material mixture while taking advantage of the technology described in the section of the conventional technology. This is done in a shorter time to improve the manufacturing efficiency and simplify the production machine.

(D) Means for solving the problem A flat lead or lead alloy current collector is insert-molded on the bottom of a synthetic resin battery case, and the current collector surface and the current collector are provided around the current collector. A stepwise portion is formed across the inner wall of the tank, a current collector surface surrounded by the stepwise portion is filled with a slurry active material, and the active material is dried to form an electrode plate. The protrusion is formed on the inner peripheral portion of the step portion so as to extend above the step portion over the entire circumference.

(E) Action Since the protrusions provided on the stepped portion can more strongly apply the tilt vibration to the slurry-like active material mixed liquid, the spreading speed of the mixed liquid is promoted, and the protrusions form the stepped portion of the mixed liquid. Is prevented from riding.

(F) Example In a weight ratio, lead monoxide 75, lead trioxide 25, hydroxypropylcellulose 0.2, and water 24 are put into a container and mixed for about 5 minutes with a stirrer to prepare a slurry-like active material mixture. On the other hand, the battery case (1) is made of high-impact styrene resin, and the punched flat plate current collector (5) made of lead or lead alloy is embedded in the battery case (1) at its peripheral edge. It is integrally formed by an insert molding method. Then, a stepped portion (2) is formed across the inner wall of the battery case (1) and the surface of the current collector, and a projection (3) is formed on the inner peripheral portion of the stepped portion (2) over the entire circumference. ) Is formed.

A mixed liquid of the above-mentioned slurry-like active material (4) in a portion surrounded by the stepped portion (2) of the battery case (1) when spread over the entire portion surrounded by the stepped portion (2) Inject dimension b) (see Figure 1). The height of the stepped portion (2) from the surface of the current collector (5) is a, and the height of the protrusion (3) from the surface of the current collector (5) is b. It matches the thickness of the liquid (4) layer. Further, (6) is a separator.

FIG. 2 shows a conventional battery case (11), which has a stepped portion (12) (height dimension a), but has no protrusions and has a thickness dimension b of the mixed liquid (14) layer such that b> a. The liquid (14) swells due to surface tension at the boundary with the stepped portion (12) and has no stepped portion (12) (third part).
(See the figure), the thickness of the electrode plate after drying is uniform, which is desirable.

If there is no step as shown in Fig. 3, the separator (26) separates the positive and negative electrodes from the locations shown in (c) to (d) of the figure.
Strict dimensional accuracy is required for the separator 26 in the AA 'direction.

Assuming that the height of the stepped portion (32) is a + α as shown in FIG.
When a + α> b with respect to the thickness b of the mixed liquid (34), not only the uniformity of the electrode plate thickness after drying deteriorates, but also the dimension of the bite part (BB ′) of the separator (36) at the time of assembly. Size)
Becomes narrower, which becomes an obstacle to making lead-acid batteries thinner.

In the lead-acid battery of the present invention shown in FIG. 1, the protrusion (3) is formed on the step (2).
By the recess (7) obtained by providing the battery, the battery is provided with a sulfuric acid electrolytic solution which is held in the separator (6) by the expansion phenomenon of the electrode plate during the charge / discharge cycle of the battery or is present on the surface of the electrode plate. It is possible to prevent leakage from the valve opening (not shown) of the safety valve that is present. In addition, a free space is required to release the pressure rise of the internal air when joining the pair of battery cases in which the positive and negative electrode plates are formed by the above-mentioned method by ultrasonic welding. Although the electrolyte may leak due to an increase in internal pressure, the recess (7) can also absorb the expanded gas due to the increase in internal pressure to prevent the electrolyte from leaking.

In addition, the mixed liquid (4) (14) (24) (34) in FIGS.
Regarding the liquid surface in, the solid line shows before drying and the broken line shows after drying.

Table 1 shows the improvement of workability in the step of injecting the slurry-like active material mixed solution. The time required for the yield and the mixed solution diffusion in the product of the present invention of FIG. 1 and the conventional product of FIG. And) is shown as a control table.

(G) Effect of the Invention As described above, the present invention inserts a flat lead or lead alloy current collector into the bottom of a synthetic resin battery case and inserts the current collector around the current collector. A step is formed between the surface and the inner wall of the battery case, the surface of the current collector surrounded by the step is filled with a slurry active material, and the active material is dried to form an electrode plate. The stepped portion when the slurry-like active material is poured into the battery case by forming a projection that extends above the stepped portion over the entire circumference in the inner peripheral portion of the stepped portion. Along with improving the yield as a product that can prevent the active material mixture from running up, the clamping force of the separator by the protrusions provided on the stepped portion can be enhanced, and the leakage of the electrolytic solution held by the separator can be prevented, and Separating positive electrode plate and negative electrode plate has the effect of improving isolation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a main portion of a lead storage battery according to the present invention, and FIGS. 2 to 4 are vertical sectional views of main portions of different embodiments of a conventional lead storage battery corresponding to FIG. Is. (1) Battery case, (5) …… Current collector, (2) …… Stepped portion, (4) …… Active material (mixed liquid), (3) …… Protrusion.

Claims (1)

[Scope of utility model registration request] 1. A flat lead or lead alloy current collector is insert-molded on the bottom of a battery case made of synthetic resin, and the current collector surface and the inner wall of the battery case are surrounded by the current collector. A stepped portion is formed, a current collector surface surrounded by the stepped portion is filled with a slurry-like active material, and the active material is dried to form an electrode plate. A lead storage battery characterized in that a protrusion is formed over the entire periphery of the portion so as to extend above the stepped portion.