Real-Time Internal Short Circuit Detection in Li-ion Battery Modules During Field Use

This paper presents a voltage correlation method for real-time detection of the early onset of internal short circuits (ISCs) in battery modules. The lack of balancing circuitry can result in the over-discharge of a single bank (cells in parallel) in a module that may lead to a possible internal short circuit that can eventually result in high temperatures and thermal runaway We formulated a statistical framework to determine the threshold voltage correlation factor, below which it is possible to create an internal short inside a cell. Through experimental data investigation, we showed that the method is robust with respect to factors such as voltage measurement noise, variations in rest time during cycling, and short-duration current pulses. The threshold determined from a control module successfully captured the early onset of ISC due to over-discharge and the specific bank at which it occurred in a module. The low computational and hardware costs make it particularly attractive for implementation in battery management systems.