Failure Analysis of Lead-acid Batteries at Extreme Operating Temperatures

Abstract

Lead-acid battery system is designed to perform optimally at ambient temperature (25 °C) in terms of capacity and cyclability. However, varying climate zones enforce harsher conditions on the automotive lead acid batteries. Hence, they age faster and exhibit low performance when operated at either extremity of the optimum ambient conditions. In this work, a systematic study was conducted to analyze the effect of varying temperatures (-10, 0, 25 and 40 °C) on the sealed lead acid. Enersys® Cyclon (2V, 5Ah) cells were cycled at C/10 rate using battery testing system. The environmental aging results in shorter cycle life due to the degradation of electrode, and grid materials at higher temperature (25 and 40 °C), while at lower temperature (-10 and 0 °C) negligible degradation was observed due to slower kinetics and reduced available capacity. Electrochemical impedance spectroscopy, X-ray diffraction and Energy-dispersive X-ray spectroscopy analysis were used to evaluate the degradation mechanism, chemical and morphological changes.