Conclusion:
The sealed lead acid (SLA) cells were cycled at -10, 0, 25 and 40 °C to evaluate the performance and degradation mechanism. Discharge profiles demonstrated that the ageing is faster at elevated temperature (40 °C) than at lower temperature (-10, 0, & 25 °C). However, capacity degradation is minimal at 0 and -10 °C due to reduced active material availability. Moreover, EIS analysis revealed that impedance change was significantly higher at 25 and 40 °C as compared to that at 0 and -10 °C. The charge transfer resistance is relatively more governing factor than ohmic resistance for indicating the degradation of the cell. XRD analysis revealed that a permanent deposition of SO4 due to surface hardening (usually termed as sulfate hardening) in the cells after cycling at all the temperatures. However, sulfate hardening is significantly higher at 25 and 40 °C as compared to that at 0 and -10 °C as confirmed from Pb/S ratio determined from EDS analysis. The study demonstrates that temperature of operation plays a crucial role in state of health prediction of sealed lead -acid batteries.