Failure analysis of lead-acid batteries at extreme operating temperatures

The lead-acid battery system is designed to perform optimally at ambient temperature (25 degrees 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 degrees C, 0 degrees C, 25 degrees C, and 40 degrees C) on the sealed lead acid. Enersys (R) Cyclon (2V, 5Ah) 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 degrees C and 40 degrees C), while at lower temperatures (-10 degrees C and 0 degrees 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.