what causes batteries to swell
Q: what cause macbook pro battery swelling? Apple battery packs contain a set of 6 lithium Ion (Li-Ion) cells (the metal covered envelopes), connectivity circuitry, and a small logic board. The main cause for battery cell swelling is what is known as thermal runaway. If a cell reaches a certain temperature then a chemical in the cell (usually Cobalt Oxide for Lithium Ion batteries) starts an unintended reaction which is exothermic in nature (i.e. it creates heat).