Fuzzy logic approach for failure analysis of Li-ion battery pack in electric vehicles

•Proposed a Fuzzy FMEA for risk assessment of an immersion-cooled battery pack in EV.•Provide a detailed assessment of the probable causes and effects of failure to the design engineers.•An analysis of battery pack functions, failure modes, causes, and effects concerning their severity, occurrences, and detection ranks.•The most important causes of failure are sealing, BMS, structure design and assembly of mechanical components.•Using fuzzy inference engine, the RPN values are modified to improve the FMEA. Vehicle electrification is one of the changes in the modern-day car enterprise trend. The battery pack is the most vital and precarious part of a battery-powered electric vehicle, which necessitates accurate and reliable designs to ensure acceptable safety. To this end, one of the tried and tested methods that help identify problems and make products more reliable is Failure Modes and Effect Analysis (FMEA). This paper presents a Fuzzy FMEA for risk assessment of an immersion-cooled battery pack (ICBP) in electric vehicles. As a new technology, immersion cooling can facilitate high-rate fast charging and a longer battery life cycle for lithium-ion batteries. Different failure modes and relevant causes and effects are investigated in this vein. Each failure's severity, occurrence, and detection rank are extracted and displayed as a standard FMEA table. The monitoring results of all stages of design, manufacture, and initial tests indicate that the most important causes of failure in an ICBP are the sealing method, BMS function, cell temperature control, structure, and assembly of mechanical components. To some extent, it was attempted to reduce the occurrence of failures by recommending actions to reduce the occurrence of those failures. Consequently, a significant improvement was achieved, and the production and installation of problematic parts were managed efficiently and effectively with the help of an FMEA control plan table.