JPH088103B2 - Lead-acid battery electrode plate manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention is intended to achieve both an improvement in conversion efficiency at the time of initial charging of a lead storage battery and an improvement in reliability such as cycle life.

2. Description of the Related Art Conventionally, various attempts have been made to mix lead tin with lead powder in order to improve the efficiency of initial charging, and the effect thereof has been clarified.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in a lead storage battery using a paste type electrode plate mixed with red lead, generally, there is a problem that the life shortens earlier as the amount of lead added is increased.

Therefore, at present, most of them have not been put into practical use except the clad type in which the active material is wrapped in a tube. Therefore, in order to improve the charging efficiency by using red lead, it is important to achieve compatibility with the service life.

Means for Solving the Problems The present invention is to improve this point, in the lead powder as the raw material of the paste, lead tin in a weight ratio to the total lead compounds.
It is characterized by mixing 10 to 40% and further mixing an appropriate amount of bismuth.

Action The effect of the present invention is that the efficiency of the initial charge is generally improved even in the region where the amount of red lead is mixed is small as compared with the case where bismuth is not added, and the life that is generally said to be decreased by the addition of red lead is improved, and It is intended to expand the area where both the initial charging efficiency and the life are compatible.

EXAMPLES The features and effects of the present invention will be described below with reference to examples.

First, prior to evaluation, lead powder according to conventional technology (bismuth content 0.0005%, other grades containing general impurities of 99.99% or more) was used, and red lead was added to this in every 5% by weight ratio to the total lead compounds. The mixture was mixed at a mixing ratio of up to 50%, and water and dilute sulfuric acid were added and kneaded according to a conventional method to form a paste. In addition to these, the lower limit of 0.0005% to the upper limit of 0.10%
The paste was prepared by adding bismuth over a wide range. Next, each paste was applied to a grid to form an electrode plate having a fixed amount of Pb, and this was used to construct a battery corresponding to a nominal 28 Ah in the conventional electrode plate configuration. Subsequently, the solution was poured into them, and 110% of the theoretical amount of electricity was charged with a charging current of 5 A, and the total amount of lead dioxide (PbO ₂ ) at that time was investigated. On the other hand, regarding the life, it is said to be a difficult point especially when adding lead tin.
4.8V 5 hours).

Fig. 1 shows the PbO ₂ conversion rate at the first charge (so-called chemical charge). Among them, A without Bi added has about 1/3 of the red lead redox already at the same oxidation level as PbO _2. Although 16% is in a state where oxidation has advanced, it can be seen that it is actually more effective.

However, the life in FIG. 2 is remarkably reduced in the bismuth-free A, and there remains a problem in practicality as a paste electrode.

Here, the bismuth-added pastes B _{1 to} B ₆ of the present invention slightly improve the efficiency of chemical conversion charging in FIG.
Significant improvement in terms of cycle life in the figure. In other words, even if the amount of bismuth added was 0.0005% (B ₁ ), no effect of improving lead life was observed when lead tin was not added, but the effect of improving lead life by combining with lead tin is effective. The effect becomes clear by increasing the bismuth to 0.001% (B ₂ ) and 0.01% (B ₃ ). Further 0.01
It decreases with a peak at 5% (B ₄ ), starts decreasing at 0.02% (B ₅ ), and reaches a life of 0.0005% or less at 0.1% (B ₆ ).

The reason for this synergistic effect on life improvement is not clear, but the fact that bismuth has a positive effect on the bond between particles and the bond between the lattice and the active material is due to the difference in softening loss during the life test, especially for lead tin. It can be seen from what is seen in the mixed area. In addition, it seems that the excessive addition of bismuth is caused by an increase in self-discharging or the like and a decrease in charging efficiency due to the significant precipitation of the dissolved material on the negative electrode side.

Effects of the Invention In any case, as described above, according to the present invention, by adding bismuth, which has been avoided as an inconvenient substance from self-discharge etc. in the paste electrode to which lead tin is not added, the life not seen when lead tin is not added As a synergistic effect of the improvement effect and the efficiency effect at the time of initial charging due to the addition of lead tin, a new area where efficiency and life are compatible is formed and expanded.

It should be noted that, in the present embodiment, both the antimony alloy and the calcium alloy are effective as the type of lattice, but the calcium alloy is more effective. In addition, bismuth can be added in various forms such as simple substance of bismuth, oxide, lead sulfate, and sulfide, and if it is a soluble salt, it can be added in the liquid unless anions are not inconvenient for battery behavior. It is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing the PbO ₂ conversion rate after initial charging, and FIG. ₂ is a diagram showing the charge / discharge cycle test results.

Claims (2)

[Claims] 1. A lead compound containing lead powder as a main component, and 10 to 40% by weight of lead tin in a weight ratio to all lead compounds as a main raw material.
In a method for producing a paste-type electrode plate in which water and sulfuric acid are added to knead a paste, 0.0005 to 0.015% by weight of bismuth is mixed with all lead compounds at the time of kneading the paste. Electrode plate manufacturing method. 2. The method of manufacturing a lead-acid battery electrode plate according to claim 1, wherein bismuth is mixed in the form of an oxide.