JPH0147862B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a lead-acid battery electrode plate substrate by machining a lead alloy thin plate.

Conventionally, grid substrates for lead-acid batteries have been made of a lead-antimony alloy containing about 4 to 8% by weight of antimony in lead. This alloy has excellent castability and sufficient mechanical strength as a lattice substrate, but antimony is eluted in the electrolyte.
This deposits on the surface of the cathode plate, and this precipitation promotes self-discharge and reduces battery capacity. At the same time, during charging, the flow rate of current increases near the end of charging or in an overcharged state, which causes Water easily decomposes and causes so-called cutting, and as a result, the electrolyte level in the cell drops below the specified level, so there is a drawback that this level must be constantly checked and water refilled as necessary. Ta.

Therefore, maintenance-free batteries have recently been developed that use lattice substrates made of lead-antimony alloys with antimony content reduced to about 2 to 3% by mass, but even substrates made of this alloy suffer from self-discharge and The current value at the time of completion of charging did not become so small.

In addition, lead-calcium alloys and lead-strontium alloys are typical alloys that do not contain antimony, but these types of alloys have low productivity when manufactured by continuous casting. For this reason, according to Japanese Patent Publication No. 55-3421, a lead-tin-arsenic alloy has been proposed as an alloy for maintenance-free battery substrates, but this type of alloy poses problems in terms of mechanical strength. Ta.

The present invention aims to provide a method for manufacturing a lattice substrate formed by a machining method for a maintenance-free battery, which has high strength, excellent corrosion resistance, and good productivity. That is, the method of the present invention is a method for manufacturing a lead-acid battery electrode plate substrate by machining a lead alloy thin plate.
A thin lead alloy sheet consisting of 1.0% by weight arsenic, 0.04-1.5% by weight tin, and the balance lead is heated to 205°C to 300°C, then rapidly cooled, then left at room temperature, and then mechanically processed to become extremely thin. It is characterized in that it can be used as a substrate for a plate.

In the method of the present invention, the steps are shown in a flow diagram as shown in FIG. 4, and the composition range of the lead alloy thin plate is shown in a ternary diagram as shown in FIG.

In preparing the lead alloy thin sheet according to the present invention, arsenic is added to improve the mechanical strength and productivity of the thin sheet. The reason for this limitation is that if the content is less than 0.04%, no improvements in mechanical strength or productivity will be observed. Moreover, if it exceeds 1.0%, the mechanical strength and productivity of the thin plate will not change compared to the case of 1.0%, and the cost will increase. Furthermore, there is a risk that cracks may occur on the end faces of the thin plate strips formed by continuous casting and rolling.

In addition, the inclusion of tin improves the production rate of thin sheets by continuous casting and rolling, and also improves the corrosion resistance and mechanical strength of the thin sheets.If the content is less than 0.04%, the corrosion resistance and No improvement in mechanical strength can be obtained and the productivity rate is also reduced. Moreover, if it exceeds 1.5%, the corrosion resistance and productivity rate will be almost the same as in the case of 1.5%, and the mechanical strength will decrease, resulting in high cost.

In addition, in the present invention, the heating temperature of the thin plate is 205 to 300℃.
The reason for rapidly cooling after heating is to impart age hardening to the thin plate, and the heating temperature is
If the temperature is below 205°C, no age hardening will be observed, and if the temperature is above 300°C, the thin plate may harden and melt.

Next, examples of the present invention will be described.

Example 1 Thin plates with a thickness of 1 mm were made by continuous casting and rolling method using Pb-0.6% and Sn-As alloys with various As contents, T _Q = 200℃,
After heating at 250° C. and 280° C. for 2 hours, it was quenched in water, left at room temperature for 3 days, and expanded to produce a 0.9 mm thick electrode plate substrate.
In addition, the ratio of the yield stress σ _0.2 obtained by conducting a tensile test at a tensile rate of 1.6×10 ^-3 S ^-1 on a sample made of a thin plate before expanding by the σ _0.2 of the Pb-0.6%Sn alloy is calculated. As shown in FIG. 1-A.

As is clear from Figure 1-A, age hardening due to rapid cooling is not observed at T _Q = 200℃, but T _Q
At =250°C and 280°C, age hardening due to rapid cooling was noticeable, and the mechanical strength was significantly improved.

Also, the average production speed of the above thin plate is Pb
- The ratio divided by the average production rate of 0.6% Sn is shown in Figure 1-B.

As is clear from Figure 1-B, the production rate ratio improved as the As content increased, and the gradient of the production rate became gentler when the As content was 0.5% or more.

Example 2 Pb-0.35As-Sn alloys with various Sn contents were made into thin plates with a thickness of 0.9 mm by continuous casting and rolling, and T _Q = 200°C.
The material was heated to 215° C. and 290° C. for 2.5 hours, immersed in water, rapidly cooled, and then left at room temperature for 5 hours, and then expanded in the same manner as in Example 1 to form a substrate. In addition, a second graph showing the ratio of the yield stress σ _0.2 obtained by conducting a tensile test on a thin plate sample before expanding at a tensile rate of 8.3×10 ⁴ S _-1 by σ _0.2 of the Pb-0.35As alloy It is as shown in Figure A.

Also, the average production speed of the above thin plate is Pb
The ratio divided by the average production rate of -0.35As is shown in Figure 2-B.

Example 3 For Pb-0.8%As-Sn alloys with various Sn contents, a thin plate with a thickness of 0.9 mm was created by continuous casting method, and this was expanded to form a substrate with a thickness of 0.8 mm. It was created. Furthermore, the ratio of the mass loss due to corrosion in the corrosion test of the thin plate before expanding to the mass loss due to corrosion of the Pb-0.8As alloy strip is shown in Figure 3.

First, the corrosion test conditions were such that a sample was immersed in an electrolytic solution with a specific gravity of 1.260 (20°C) and then energized at 0.5A (A) for 350 hours, and then taken out and the mass loss due to corrosion was measured.

As is clear from Figure 3, the Sn content is 0.9 to 1.0%.
It was observed that the amount of corrosion was minimized.

As detailed above, according to the method of the present invention, since the alloy does not contain any Sb, self-discharge is extremely small, and it also has excellent mechanical strength and corrosion resistance, and the production rate of alloy thin sheets is significantly increased. It has a great effect.

[Brief explanation of drawings]

Figures 1 to 3 show the characteristics of the alloy thin plate obtained by the method of the present invention, Figure 1A is a relationship curve between As content and age hardening ratio, and Figure 1B is a graph showing the relationship between As content and age hardening ratio.
The relationship curve diagram between content and production rate ratio, Figure 2A is
Figure 2B is a relationship curve between Sn content and age hardening ratio. Figure 3 is a relationship curve between Sn content and mass reduction ratio. Figure 4 is a relationship curve between Sn content and mass reduction ratio. The figure is a process flow diagram of the method of the present invention, and FIG. 5 is a ternary diagram showing the composition range of the lead alloy plate in the present invention.

Claims (1)

[Claims] 1 0.04-1.0% by weight of arsenic and 0.04-1.5% by weight
A lead alloy plate consisting of tin and the balance lead is heated at 205 to 300℃.
1. A method for manufacturing a lead alloy storage battery electrode plate substrate, which comprises heating the electrode material to a temperature of 100 mL, then rapidly cooling it, leaving it at room temperature, and then machining it to obtain an electrode plate substrate.