Generally, Li-ion cell failures can give rise to both reliability and safety concerns.
Most often, a Li-ion cell will fail in a manner which makes it inoperable such that it is
unable to be charged and / or discharged. However, in some instances, a Li-ion cell may fail exothermically. An exothermic failure of the cell is referred to as the cell going into “ thermal runaway. ” This mode of failure though is rare for the chemistry. Although infrequent, occurrences of cell thermal runaway can be highly destructive and pose a fire hazard. Accordingly, it is important to address safety concerns when designing and specifying systems using Li-ion cells.
shows the remnants of a multicell Li-ion battery after thermal runaway of
the cells. In this incident, the heat generated by the exothermic failure of one of the cells
caused a failure and thermal runaway of the other cells in the battery.