On thermal safety characteristics of rechargeable alkaline batteries based on zinc and manganese dioxide

As lithium-ion technology's exhibits inherent issues with safety due to thermal runaway, a sustainable and cheaper alternative has been proposed in this work: the rechargeable alkaline battery chemistry. However, so far, the postulated safety of the new battery chemistry has not been demonstrated adequately. Therefore, a safety study is being carried out for rechargeable alkaline battery cells. This Short Communication paper is the first report on the thermal safety of Zn-MnO₂ CR2032 rechargeable alkaline battery coin cells. 100 % charged coin cells were tested under thermal abuse conditions in a gravity-convection furnace to quantify the temperature at which the cell would go into thermal runaway. Morphological characterisation of pristine and tested cells was performed via laboratory-based X-ray computed microtomography. The onset temperature to thermal runaway for the rechargeable alkaline battery cells was found to be in the range of 290–380 °C, much higher than that reported in the literature for lithium-ion cells (150–200 °C) of similar capacity and geometry. These results emphasise that rechargeable alkaline battery technology has improved thermal stability compared to lithium-ion technology. Lastly, morphological analyses highlighted the variations of cell geometry brought about by thermal testing.