Failure analysis methodology for battery powered product incidents

Low cost, high energy density and high reliability have made Lithium ion batteries the preferred choice for powering rechargeable battery-operated products. Lithium ion battery packs are now finding their way into new markets such as power tools and hybrid vehicles. Manufacturers employ various design topologies and comprehensive battery management systems to manage the battery and ensure its operation in its reliable operating range. A failure within the cell or the control electronics can cause the cell to fail or go into thermal runaway. Thermal runaways in Lithium ion cells are rare but may be energetic in nature. A systematic methodology can be implemented to determine the cause or the likely cause of the failure event. Once the cause is determined, the necessary corrective action can be developed and implemented. This paper describes a systematic approach to determine the likely cause of a consumer product battery failure.