Failure analysis of lead-acid batteries at extreme operating temperatures

The 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 automotive lead-acid batteries. Hence, they aged faster and showed lower performance when operated at extremity of the optimum ambient conditions. In this work, a systematic study was conducted to analyze the effect of varying temperatures (−10°C, 0°C, 25°C, and 40°C) on the sealed lead acid. Enersys® Cyclon (2 V, 5 Ah) cells were cycled at C/10 rate using a battery testing system. Environmental aging results in shorter cycle life due to the degradation of electrode and grid materials at higher temperatures (25°C and 40°C), while at lower temperatures (−10°C 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 and chemical and morphological changes.