Research of mechanical characteristics of pb-ca-sn alloys and tapes for cur-rent leads in sealed lead-acid batteries (Vrla)

Abstract

Purpose. The modern trend in lead-acid battery industry is the changeover to reliable and safe leak-proof VRLA batteries. However, the properties of grid alloys of these batteries are still insufficiently studied, that hampers application of these batteries at railway transport. The purpose of this work is the research of dependence of mechanical properties of grid alloys on temperature conditions of casting, deformation of rolling and ageing time. Methodology. Mechanical properties of alloys and grids have been defined at standard tensile testing machine R-0,5. Findings. The rolling of lead-calcium alloys with deformation more than 90% raises their durability and reduces their plasticity. When rising the temperature of the casting moulds (in range 60-170°С) the durability of lead-calcium and lead-antimony alloys decreases, and the plasticity increases, that are mostly evident for PbCa0.1Sn0.3 alloy, and least of all – for PbCa0.05Sn1.1 alloy. Durability of lead-calcium and lead-antimony alloys increases and plasticity decreases with increasing the time of ageing: this is mostly evident for alloy PbCa0.05 Sn1.1 and strips made from it. Originality. It was determined that decrease of alloys overcooling at crystallization results in drop of their durability and increase of plasticity. The composition and structure of alloys strongly influence dynamics of their ageing. Practical value. It is proposed by authors: a) to increase the temperature of crystallization of alloy for negative grid strip to 120-160°С instead of 80-120°С, that will raise plasticity of strip and reduce deterioration of the equipment; b) to replace PbSb1.8Se alloy of cast grids by PbCa0.1Sn0.3 alloy, that will allow reducing weight of grids by 25 % at the same durability; c) to increase range of ageing of grids cast from PbCa0.1Sn0.3 alloy to 3-30 days that reduces the production costs. It’s all taken together will reduce deterioration of the process equipment and cut down production cost at conservation of characteristics of production.