JPH0551147B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in substrates for lead-acid batteries.

Prior Art Conventional technology aimed at modifying the surface of a substrate and its drawbacks will be explained.

1 Plating method The plating surface tends to become rough, and washing and drying with water before and after plating is required. Managing the plating bath is complicated. The finish of the plating varies depending on the design of the base.

2 Welding method Sprays molten metal, but the bonding force with the base surface is weak. This is because the sprayed particles are small and each particle has a small heat capacity. In addition, particles overlap and become more and more brittle and peel off.

3 Thin film pressure bonding method When an extremely thin film is pressure bonded and rolled or heat treated, it will peel off if there is even the slightest distortion due to the difference in physicochemical properties from the base body.

Problems to be Solved by the Invention Although it is easy to uniformly process the surface of the lattice body using conventional manufacturing methods, it is difficult to maintain the crystalline bond between the active material and the lattice body, which is particularly important in anode plates. It is disadvantageous in the following points.

Since the electrode plate is completed with the added surface layer bonded to the anode active material, when the added surface layer begins to be oxidized or reduced, the charge/discharge characteristics of the battery begin to deteriorate rapidly.

Means for Solving the Problems In view of the above-mentioned problems, the present invention aims to supply molten tin or a lead-tin alloy at a high temperature through a pipe with a constricted tip, and to supply the molten tin or lead-tin alloy between the surface of the base material and the surface of the base material. The area (or volume) of the supply portion is controlled by the diameter of the pipe and the number of supply operations from the pipe. By fully alloying the applied part and integrating it with the base material, the performance of the battery during use can be stabilized, and the applied part can be made in spots on any desired surface area. .

Function: Alleviates the effects of electrical resistors generated on the surface layer of the substrate.

EXAMPLE Even when tin or lead-tin alloy is oxidized, it forms highly conductive SnO ₂ and maintains the electrical connection between the active material and the substrate. Further, according to the method of the present invention, since the alloy layer has a larger amount of tin than the substrate, tin is diffused into the interior of the substrate, and the oxidation resistance of the substrate is also improved. In this way, the electrical connection of the base active material is maintained well, and the corrosion resistance of the base is also improved.

Next, an example of processing a substrate according to the present invention will be described.

The pipe 2 for supplying the molten tin or lead-tin alloy 1 was made of stainless steel and had an inner diameter of 3 mm and a wall thickness of 1 mm, and the tip nozzle was narrowed to an inner diameter of 0.8 mm. tin
60% lead-tin alloy 1 in pipe 2 at 350±10℃
Keep it in a molten state. The substrate is fed horizontally, the nozzle is brought into contact with it, and then pulled apart after a certain period of time. This isolates it from the outside air and alloys it with the substrate surface. Oxygen and moisture from the outside air are blocked, and a uniform alloy layer can be quickly created.

A base body 3 was prepared by punching out a lead alloy sheet (thickness: 0.5 mm), and a pipe 2 having a heater 4 was filled with lead-tin alloy 1 and melted, and lead-tin alloy 1 was supplied at about 80 spots on one side.

FIG. 3 shows the state of the substrate after processing. The state of the cross section near the spot is shown in FIG. 4, and the spot has penetrated into the interior of the base and is alloyed.

In order to confirm the effect on life, the above-mentioned processing was performed using a lead alloy sheet containing 0.1% Ca and 0.2% Sn as an alloy composition. A battery was manufactured by filling the processed base with paste for anode and cathode to prepare electrode plates. Battery capacity is 28Ah.
Batteries using unprocessed substrates were also produced.

The life test conditions are shown below.

Discharge 60% (5.6A, 3h) Charge 115-118% (15.6V cut, 5h) Temperature 30±5°C The results are shown in Figure 5. It can be seen that battery A using the substrate according to the present invention exhibits approximately twice the life performance. B is a battery using a conventional substrate. It can be seen that the charging and discharging characteristics were improved by the processing according to the present invention.

In order to directly examine the results of suppressing the growth of electrical resistors generated on the surface layer of the substrate, a completely ready-to-use battery was prepared, a storage test was conducted, and the discharge voltage after storage was investigated. The fabricated battery was exactly the same as the life characteristics evaluation, but the alloy composition of the lead alloy sheet was 1.8% Sb and 0.5% Sn.
%.

To investigate storage performance, after a certain period of time, the samples were removed from the storage case at 60°C and cooled to 0°C. The electrolyte solution is also separately cooled to 0°C. After removing the sealant sealing the battery and injecting the cooled electrolyte
Discharge 150A and measure the voltage for 5 seconds.

The results are shown in Figure 6. Battery A using a processed substrate had a level of 8.0V even after storage at 60°C for 10 days, which was a significant improvement compared to Battery B using an unprocessed substrate.

The phenomenon of decrease in discharge voltage during storage is "thermal passivation"
This is because an electrical resistor consisting mainly of Pb0 is generated and grows on the surface layer of the substrate. 60
It is known that the growth rate becomes faster at ℃. It can be seen that the battery according to the present invention is effective in modifying the surface layer of the grid.

Note that 1' is a lead-tin alloy applied to the base body 3.

Effects of the Invention As described above, the present invention is capable of modifying the surface of a base while making use of the base material, and is capable of improving the life characteristics of lead-acid batteries by improving their charging and discharging characteristics. The cost is enormous.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a lead-tin alloy melt supply device and substrate processing method, Fig. 2 is a front view of a substrate made from a lead sheet, and Fig. 3 is processed into the substrate shown in Fig. 2. FIG. 4 is a sectional view of the base body, showing the state of alloying in the spot portions. FIG. 5 is a life characteristic diagram of a battery using the substrate according to the present invention and a battery using a conventional substrate, and FIG. 6 is a curve diagram showing the results of the storage test. 1 is a base made of tin or a lead-tin alloy, and 3 is a base made of a sheet material.

Claims (1)

[Claims] 1. A fixed amount of tin or lead-tin alloy is supplied as a spot onto the surface of a substrate made of lead or a lead alloy, maintained at a temperature higher than the melting point of the substrate and isolated from the outside air,
A method for manufacturing a base for a lead-acid battery, characterized by melting a surface layer of the base to integrate an alloy.