Any energy storage technology can be dangerous if the energy gets in or out too quickly. For example, if charged too quickly, LA batteries can heat up and be damaged and even explode. Similarly, an LA battery that’s discharged too quickly (such as a short circuit), can spark and ignite lingering hydrogen gas. Lithium technologies, relying on a chemical reaction to store energy, are no exception. Two incidents were widely publicized—impurities combined with oxide-based lithium batteries fostered thermal runaway, causing laptop computers to overheat and catch fire; and the 2011 Chevy Volt fire, in which the coolant from the battery system dripped onto the ruptured batteries in a junkyard Volt and caused a fire. (General Motors has redesigned the battery system to reduce the likelihood of another incident.)
Of all of the Li-ion chemistries, lithium iron phosphate (LiFePO4 or LFP) offers the most stable chemistry and is considered very safe. For this reason, LFP is used for most large-capacity Li-ion batteries, and is the most common type used in EVs and telecom power systems.