JPH01143147A - Lead storage battery - Google Patents

Abstract

PURPOSE:To improve the overdischarge characteristic and life characteristic by using an electrode plate substrate made of a Pb-Ca-Sb-Zn alloy added with Zn to a lead alloy made of Ca and Sb with the specific weight ratio. CONSTITUTION:The Sb concentration is limited within the range not affecting the self discharge, i.e., 0.01<=Sb<=0.1wt.%, Ca is set to below 0.09wt.% with little cycle capacity deterioration and lattice expansion, and a Pb-Ca-Sb alloy containing Zn is used. As a result, compounds such as Sb2Zn3 and Sb3Zn4 are generated between Zn and Sb to hold the conductivity of an electrode plate substrate, the storage performance is made very excellent because the Sb concentration is limited. The overcharge characteristic, capacity recovery rate, overdischarge characteristic, cycle life, and storage performance can be thereby improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a grid plate for providing a lead-acid battery with low self-discharge and excellent over-discharge characteristics and life characteristics.

Conventional grid plate alloys for lead-acid batteries include pb-sb alloys and Pb-sb alloys.
b -Ca-based alloy is used. But pb-s
Self-discharge is large in B-based alloys (and corrosion resistance is poor in Pb-Ca-based alloys).

Problems to be Solved by the Invention The pb-sb alloy has disadvantages in that the hydrogen overvoltage of sb is small, so self-discharge is large, and water decomposes frequently during charging, resulting in large water loss. -Pb-Ca alloys have a significantly short lifespan when used in deep discharge cycles, and furthermore, they become difficult to charge after long periods of continuous discharge or are left in an open circuit state in a discharged state, resulting in an extremely reduced capacity. There are some drawbacks. The cause of the deterioration of overdischarge characteristics and the cause of deterioration due to deep discharge cycles is that irreversible PbSO4 and Pb oxide (pbo) are generated at the interface between these alloy lattice plates and the positive electrode active material. It is thought that the resistance between the lattice, which is a current collector, and the active material deteriorates, resulting in deterioration.

Means to Solve the Problems Grid plates for lead-acid batteries must have excellent current collection and active material retention, high mechanical strength, good conductivity, and excellent corrosion resistance. Moreover, it is preferable that the price including workability is low. In conventional alloys,
There were pros and cons in terms of performance. Although alloys containing sb have good adhesion to active materials, they have the disadvantage of large self-discharge. First, the Sb concentration is lowered than before, and within a range that does not affect self-discharge, 0.01≦sb≦0.1w.
The sb concentration was limited to t%. Further, Ca was set to less than 0.09 wt%, which caused less deterioration of cycle capacity and less elongation of the lattice. Further, by using a Pb-Ca-5b alloy containing Zn, self-discharge is small (over-discharge characteristics and life characteristics can be improved).

In the Pb-Ca alloy, the lattice current collector itself may stretch due to intergranular corrosion and become unable to hold the active material, or if this case is used for the positive electrode lattice plate, it may contact the strap on the negative electrode side and short circuit. do. In addition, in the pb-sb gold alloy, sb is dissolved and deposited at the cathode and degrades battery performance. Therefore, the inclusion of Zn has an effect on overcharge characteristics, cycle life, and storage performance.

This is because 5bzZn3 and 5b3Z between Zn and sb
It is thought that a compound called n4 is generated to maintain the conductivity of the seed plate substrate. Also, the sb concentration is 0.01≦sb
Since the content is limited to ≦0.1 wt%, the storage performance is also very superior compared to conventional Pb-Sn alloys.

Example 0.06wt% Ca, 0.05wt% S in pure PB
A lattice containing 1.0 wt % of Zn and 1.0 wt % of Zn was prepared, filled with paste, and subjected to normal aging and drying to obtain a positive electrode plate.

After chemical formation, the battery was assembled to produce a 4 Ah-4V battery. As a comparative example, a similar experiment was conducted using a Pb-Ca 0.1% gold alloy and a Pb-5b 5.0% gold alloy.

(1) Capacity recovery rate After charging the battery, discharge it for 24 hours at 1.7Ω, and then
After being left in a room at °C, constant voltage charging at 4.9 V (1.2 A limit) was performed for 24 hours, and the ratio to the initial capacity was calculated.

(2) Overcharge characteristics After charging the battery at 1.2A for 7 days at 25°C, repeat the same charging and discharging, and check the overcharge characteristics with the amount of electricity charged until the discharge capacity becomes 60% of the initial value. evaluated.

(3) Cycle life Discharge to 3.4■ at a discharge current of 800mA, 400mA
A charge/discharge cycle of charging for 11 hours was repeated, and the number of cycles until the discharge time reached 60% of the initial value was measured.

(4) Storage performance After charging, the battery was left in a gas phase at 45°C, and the capacity was measured one month later, and the ratio to the initial capacity was calculated.

The results obtained in the above tests are shown in FIGS. 1 to 4.

As can be seen from Figure 1, the capacity recovery rate after overdischarge is significantly higher than that of conventional Pb-Ca alloys.

It has increased. It can also be seen that it is superior compared to pb-sb. It can be seen from FIG. 2 that the alloy to which Zn is added has a longer overcharge life and is superior to conventional alloys. Furthermore, it can be seen from FIGS. 3 and 4 that the alloy grid plate containing Zn is effective in improving cycle life and storage performance. FIG. 5 shows the elongation of the lattice with respect to Ca 4 degrees, which shows a gradual increase up to 0.09 wt % of Ca 1 degree, but a rapid increase when it exceeds 0.09 wt %. Therefore, the Ca concentration is 0.0
It has been found that less than 9 wt% is suitable.

Effects of the Invention The Pb-Ca-Sb-Zn alloy of the present invention contains Ca,
, does not impair the properties of Sb, has excellent mechanical strength, and has good adhesion to the active material.Furthermore, by incorporating Zn, the capacity recovery rate after overdischarge, overcharge characteristics, cycle life, and storage performance are improved. It also has great industrial value, as it has the advantage of being able to improve the process.

[Brief explanation of the drawing]

Figure 1 shows the capacity recovery rate after overdischarging compared to the conventional P
Comparison diagram of b-Ca alloy and pb-sb gold alloy. Figure 2 is a comparison diagram of overcharged electricity showing overcharging characteristics with conventional alloys. Figures 3 and 4 are graphs of cycle life and storage. A comparison diagram with conventional alloys in terms of performance, Figure 5 shows Pb-C
The curve □□□ represents the elongation ratio of the lattice plate to the Ca concentration in the a-based alloy. Figure 1 Figure 2 Figure 3 Figure 15b-;g 几

Claims (1)

[Claims] Less than 0.09wt% Ca and 0.01-0.1wt
Pb-Ca-S made by adding Zn to a lead alloy consisting of %Sb
A lead-acid battery characterized by using an electrode plate substrate made of a b-Zn alloy.