Internal Short Circuit Warning Method of Parallel Lithium-Ion Module Based on Loop Current Detection

Abstract

Internal short circuit is one of the main triggers for thermal runaway of Li-ion batteries, however, internal short circuit is incidental and cannot be predicted in advance. Therefore, improving the sensing capability of internal short circuit is especially important to improve the safety of electric vehicles. In this paper, we propose an algorithm for detecting internal short circuit of Li-ion battery based on loop current detection, which enables timely sensing of internal short circuit of any battery in a multi-series 2-parallel battery module by detecting the loop current. The method only needs to detect the voltage at both ends of the diagnostic resistor (3 measurement points), which has the advantages of fewer detection points and less additional wiring to the battery module, and can avoid the safety hazards caused by excessive wiring while protecting the battery module. The experimental results show that the method is able to detect internal short circuits in parallel lithium-ion battery packs in a timely manner.