JPH0565986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement in a method for manufacturing lead-acid batteries.

Conventional technology In conventional cast-on-strap manufacturing of electrode plates, when molten lead is fed into the engraved part of the mold, the cooling rate of the lead is partially different at the contact area between the molten lead and the mold, causing the strap to There was a drawback that there was a difference in the melting state of the ears in the outer and inner electrode plate groups.

Problems to be Solved by the Invention In the carved portion 2 of the mold 1, the molten metal 3 supplied with lead is cooled from the contact portion 4 with the mold 1.
The solidification process of the molten lead 3 in this case is shown in FIG.
Therefore, when the ears 5 of the electrode plate group are immersed in molten lead 3 as shown in FIG. As shown in the solidification curve 6 shown in the figure, variations occur in the welded state of the tip of the electrode plate lug. When manufacturing variations are taken into account, there are quality problems such as the edges of the electrode plate not melting, and it is extremely difficult to stabilize the product.

Means for Solving the Problems In view of the above points, the present invention provides a material having poor thermal conductivity compared to the mold material, such as ceramic, in the carved part of the mold, where the supplied molten lead cools quickly. The purpose of this invention is to control the heat balance of the molten lead in the strap to make the solidification rate uniform, and to control the heat balance of the molten lead and adjust the solidification rate by providing the above-mentioned material in the strap.

Function: The multiple ears of the electrode plate group within the strap are melted to the same state as both ends and the center, and welded uniformly.

Example In the contact portion 4 between the mold 1 and the molten lead 3, cooling of the lead progresses rapidly. In particular, this tendency tends to be remarkable in the strap portions corresponding to the tabs on both ends of the electrode plate group. Therefore, as shown in Figure 1, a ceramic material 7 with a thermal conductivity of approximately 1/20 of that of the mold material was manufactured by carving the mold 1 corresponding to the above-mentioned portion by electric discharge machining, etc. Good) Built-in and retained. The type and size of the material to be incorporated are determined through experiments, etc. In this example, mica-based ceramic has a thermal conductivity of 1.68 Kcalmihv・℃ (800
(at ℃), specific heat, 0.29 cal/g・℃ (RT~800℃)
I used the one from

Note that 6' is a solidification curve. Further, the final freezing point of the terminal strap portion overlaps with the electrode plate edge, which may impair welding quality, but by applying the present invention, the final freezing point can be shifted.

Effects of the Invention As described above, according to the present invention, in a cast-on-strap mold, a material having a lower thermal conductivity than the mold material is provided in a part of the mold to reduce the solidification rate of molten lead in the carved part of the mold. This uniformity reduces the variation in the welding condition of the tip of each electrode plate in the strap of the electrode group, stabilizes and improves the welding quality of the electrode group, and improves the reliability of the cast-on strap method for lead-acid batteries. It has tremendous industrial value, such as improved performance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing how ceramic is incorporated into a mold according to the present invention, FIG. 2 is an explanatory diagram showing the solidification process of molten lead according to the present invention, and FIG. 3 is an electrode plate group according to the present invention. Figure 4 is an explanatory diagram showing the shape of the strap carved in one place in the cast-on strap mold. Figure 5 is the conventional solidification of molten lead in the carved part of the mold. FIG. 6, which is an explanatory drawing showing the process, is a schematic diagram showing the welding state of the electrode group electrode plate ears in the conventional method. 1 is a mold, 3 is molten lead, and lead is ceramic.

Claims (1)

[Scope of Claims] 1. In a method of welding a group of electrode plates using the cast-on-strap method for a lead-acid battery, a material having a lower thermal conductivity than the mold material is used in a mold with both ends of the electrode group facing toward the plate ears. A method for welding a group of electrode plates using a cast-on strap method for a lead-acid battery, characterized by using a mold placed on the surface or inside.