JPH0770321B2 - Sealed lead acid battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention is used in various fields for portable devices, and has recently been in rapid increase in demand, and has been used for VTR power supplies and the like, sealed lead-acid battery. Related to the improvement of.

2. Description of the Related Art There are many proposals for sealed lead-acid batteries. As a typical example, the amount of electrolyte is set to the pore volume of the electrode plate group or less, so that there is no so-called free liquid, and oxygen gas generated from the anode plate at the end of charging is absorbed by the negative electrode plate to reduce the electrolyte solution. The method of suppressing is being operated. Since this sealed lead-acid battery has no free liquid, it does not leak even if it is tumbled or placed upside down, and since it does not require rehydration, it is used in many fields.

Problems to be Solved by the Invention Although batteries of this system are widely used for trickle applications and cycle applications, in that case, the batteries are often overcharged. When overcharged, deterioration of the anode plate during charging, i.e. formation of a passivation layer at the interface between the active material and the lattice,
In addition, the decrease in capacity due to the decrease in electrolyte solution has been a problem. In order to solve this problem, it is effective to use a lead-antimony alloy as the anode lattice alloy. However, in that case, antimony in the anode grid is dissolved in the electrolytic solution and is further deposited on the cathode plate. At that time, since the hydrogen overvoltage of antimony is small, the self-discharge is large,
There has been a problem that the amount of electrolytic solution is significantly reduced.

The present invention solves the above problems. That is, it discloses an anode plate which is excellent in overcharge characteristics while suppressing self-discharge and reduction of the electrolytic solution.

Means for Solving the Problems The present invention has a tin content of 0.05 to 3.0% by weight, a calcium content of 0.01 to 0.04% by weight, and a bismuth content of 0.001%.
To 0.1% by weight, with the balance being lead-tin-calcium-bismuth alloy and a positive electrode plate provided with a grid body made of a bismuth alloy, a negative electrode plate, and a separator. . The overcharge characteristics of this battery were superior to those of the conventional one, and the electrolytic solution did not decrease due to overcharge.

Action In the battery using the grid body of the present invention for the anode plate, even when overcharged, the grid of the anode plate, since the passivation layer is not formed at the active material interface and the electrolytic solution is not reduced, Capacity deterioration is unlikely to occur.

Examples Examples of the present invention will be described below.

A cast grid having a tin content in the range of 0 to 5.0% by weight, a calcium content in the range of 0 to 0.1% by weight, and a bismuth content in the range of 0 to 0.2% by weight and used as an anode A sealed lead-acid battery was constructed from a plate, a glass mat separator, and a cathode plate. However, the grid for the cathode plate was manufactured by casting from lead and calcium alloy (calcium content 0.1% by weight).

Combine these 2 cathode plates and 1 anode plate to obtain 12V10
A battery with a rate discharge capacity of 1.2 Ah was produced. In addition, sulfuric acid having a specific gravity of 1.34 was used as the electrolytic solution of the battery, and the amount of the electrolytic solution was adjusted so that no free solution existed.

The battery was charged at a current of 10 hours, then discharged at a current of 5 hours to confirm the initial capacity, and then continuously overcharged at a constant current of 0.1 A for one month. After overcharging, the battery was discharged at a rate of 5 hours, and the ratio of the capacity to the initial capacity was defined as the capacity remaining rate.

Fig. 1 shows the relationship between the tin content in the anode grid and the capacity retention rate when the calcium content was used as a parameter, and Fig. 2 shows the calcium content and the capacity retention rate when the tin content was used as a parameter. Showed a relationship. In any case, the content of bismuth is 0. As shown in Fig. 1 and Fig. 2, the over-discharge characteristics of the battery using the anode / platinum of the lead / calcium tin alloy with the tin content of 0.05 wt% or more and the calcium content of 0.04 wt% or less are It is clear that it is excellent. However, if a battery with a tin content of 3.0 wt% or more is left in an overcharged state,
Some batteries are short-circuited, which is not preferable in terms of quality. When the calcium content is 0.01 wt% or less, the mechanical strength of the lattice becomes extremely weak, and deformation occurs when the active material is kneaded or processed, which is not preferable in production.

Therefore, for a battery using lead, calcium, and tin alloys with a tin content of 0.05 to 3.0 wt% and a calcium content of 0.01 to 0.04 wt% for the anode grid, the anode plate grid has excellent mechanical strength. Overcharge characteristics are better than conventional ones,
It does not deteriorate other battery characteristics. However, the castability of the lattice is poor only with lead, calcium, and tin alloys. Although the reason is not clear, when bismuth is added to the alloy in the range of 0.001 to 0.1 wt% to improve the castability, the flow of molten metal to the narrow portion of the lattice is improved and the castability of the lattice is remarkably improved. Even if the amount of bismuth added is larger than the above range, at least the castability of the lattice is significantly deteriorated. Third
The figure shows an example of the results of castability. That is, the tin content is 3.
The defective rate is shown when a lattice is cast from an alloy having a content of 0 wt%, a calcium content of 0.1 wt% and a bismuth content of 0 to 0.3 wt%. From this figure, the content of bismuth is 0.001-0.1
It is suggested that the defect rate is low in the wt% range.

EFFECTS OF THE INVENTION As described above, the present invention discloses an anode plate grid that improves overcharge characteristics without deteriorating other battery characteristics, has high mechanical strength, and is excellent in castability. is there. It is the effect of calcium and tin in the anode grid that improves the overcharge characteristics. The cause is only presumed, but the synergistic effect of calcium and tin may have been improved to be preferable for the overcharge characteristics of the oxide film formed by overcharge on the lattice surface. The addition of bismuth to the anode grid does not have any adverse effect on the improvement of such overcharge characteristics.

[Brief description of drawings]

FIG. 1 shows the case where the calcium content is used as a parameter,
FIG. 2 is a characteristic diagram showing the relationship between tin content and capacity retention ratio,
The figure is a characteristic diagram showing the relationship between the calcium content and the capacity retention rate when the tin content is a parameter, and FIG. 3 is a characteristic diagram showing the castability.

Claims (1)

[Claims] 1. A tin content of 0.05 to 3.0% by weight, a calcium content of 0.01 to 0.04% by weight, and a bismuth content of 0.00.
A sealed lead-acid battery comprising an anode plate, a cathode plate, and a separator having a grid of a lead-tin-calcium-bismuth alloy with the balance being lead in the range of 1 to 0.1% by weight.