A quantitative internal-short-circuit diagnosis method of lithium-ion batteries for float charging systems

The diagnosis of internal short circuit (ISC) faults in lithium-ion batteries (LIBs) plays an important role in improving battery safety and reducing the occurrence of fire and explosion accidents. Traditional ISC diagnosis methods mainly focus on dynamic operating conditions, and rarely consider stable float charging scenarios with high risks. This paper proposes a quantitative diagnosis strategy for ISC faults in LIBs under different float charging conditions. First, a simulation model of ISC faults for single cells and battery modules under float charging conditions is established. Then, for the LIB packs without a balancing system, three quantitative diagnosis methods (namely Map-based, constant-voltage-source based, and intermittent-charging based) for the ISC faults applicable to different simple and complex float charging systems are proposed. Finally, the method is verified through simulation and experiments, and the results show that an ISC of 0-500 Omega can be detected in various scenarios, and the proposed methods are low-cost, high-precision, and easy to implement for early ISC diagnosis of float charging systems for energy storage.