Investigation into the thermal response of internal short-circuit treatment of a cylindrical lithium-ion battery cell jacketed with passive cooling

This study investigates the influence of passive cooling of N-octadecane phase change material (PCM) on a cylindrical 18650 Panasonic Lithium-ion (Li-ion) battery cell subjected to internal short circuits due to mechanical damage including crushed, punctured, or dropped batteries and or vibration or impact during usage (e.g. EV crashes). In experimental practices, nail penetration is one of the harshest
mechanical damages which can be induced to batteries for testing safety, reliability, longevity, and efficiency of electrical energy storage (EES). The primary focus of this investigation is to comprehend the thermal performance of individual Li-ion cells under an induced mechanical damage (i.e. nail penetration as the harshest induced and controlled mechanical damage to batteries) with a key emphasis on Li-ion battery safety, mitigation of EV battery fires, short circuit testing, and the application of PCMs. A detailed research methodology unfolds, encompassing simulation parameters which affect
performance employing ANSYS fluent to analyse the effects of varying patch sizes from subsequent damage. With consideration towards the maximum cell temperature and state-of-charge (SOC), various internal short-circuit patch sizes (represents nail penetration sizes of 1mm, 3mm, 5mm, and 8mm), incorporating specific short-circuit resistance to the battery configuration are analysed in the absence and presence of the PCM. The discharging process using an equivalent circuit model (ECM) from a multi-scale multi-domain (MSMD) approach is executed by reducing the battery charge from the initial
100% to 0% at ambient weather temperature conditions (25°C). The tests are benchmarked against safety critical temperatures at cell level for 60°C and 170°C, which represent the manufacturer safety limit and thermal runaway potential limit respectively, offering a comprehensive evaluation of the PCM's impact. These parameters offer a crucial insight into the electrical performance of the battery during discharging/charging cycles, making optimum temperature control a key factor in mitigating issues like overheating, thermal runaway and potential fire/explosion. Integrating the PCM-based jacket presents a promising solution to these thermal challenges and may offer precise temperature regulation amid internal short-circuit events.