SIMULATION OF THE CAST-ON-STRAP PROCESS IN A FINITE-ELEMENT MODEL

A decisive factor of the quality of lead/acid batteries, in terms of p erformance and life time, is the fusion of the plate lugs to the cast- on-strap (COS). The fully automatic COS process is nevertheless comple x and the resulting quality of fusion depends on a number of different parameters such as: the strap volume, the number of lugs, the thickne ss and the insertion depth of the lugs, the combination of strap and l ug alloys, and the thermal parameters such as the temperatures of the melt and the strap mould. To further improve the understanding of this important manufacturing process we have used a finite-element analysi s to determine the relative influence of some of these parameters on t he thermal history and on the resulting quality of fusion. Simulating a technical process such as COS needs simplification and model assumpt ions and will not be complete without experimental verification. Detai ls of our approach are given and representative results are discussed. It is concluded that COS simulation is a valuable tool for identifyin g robust process conditions and optimizing product quality.