Battery swelling is a phenomenon most users of electronic devices probably have experienced or heard of. It happens when a battery actually swells outward, sometimes deforming or damaging a device that it is powering. Though it seems to be some form of nuisance or cosmetic issue, a swollen battery is a serious problem and can cause serious safety risks. Understanding why this happens and how to address the problems related to it can help avoid hazards and increase the life span of the devices. What Causes Battery Swelling? 1. Chemical Reactions in Lithium-Ion Batteries Most modern devices these days use lithium-ion (Li-ion) or lithium-polymer (LiPo) due to their high energy density and long life span. However, these batteries are not without problems, and swelling is a common symptom of chemical reactions gone bad. Lithium-ion batteries work on the principle that lithium ions move from an anode to a cathode, during the charging and discharge cycle. Chemical reactions occurring inside t...