Random Hardware failure compliance of a cell balancing circuit with the requirements of automotive functional safety

Lithium ion batteries have become established as an energy storage for electric vehicles. An essential component for optimal utilization of the stored charge is a cell balancing between the individual cells. There are several standard applications on the market now. In this paper it is shown by an example that a standard cell balancing circuit is compliant with the requirements of ISO 26262 with respect to random hardware failure. As an example the circuit is being evaluated whether it satisfies the requirements of the safety goal “overcharging shall be prevented” with respect to random hardware errors.