Thermal runaway risk assessment of pouch cells with modified current collectors under mechanical abuse

This work presents an experimental study to evaluate the thermal runaway (TR) risk of pouch cells with modified current collectors (MCCs), which incorporate polyethylene terephthalate (PET) for mitigating internal short circuits and further preventing TR. Two types of cells, with capacities of 5 Ah and 10 Ah, were adopted and subjected to nail penetration tests. The results showed that the 5 Ah MCC cells exhibited improved safety, with only one out of four undergoing TR, compared to both control cells without MCCs experiencing TR. In contrast, all 10 Ah cells, including those with MCCs, experienced TR, indicating that the MCC's protective benefits may not apply to higher-capacity cells under similar test conditions. Comprehensive post-mortem analyses, including computed tomography (CT) scans, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), were performed to assess the internal structural and compositional changes. The findings indicate that MCC technology significantly reduces TR risk in lower-capacity cells, while additional safety measures may be requited for the higher-capacity cells . This study highlights the potential of MCC technology to enhance battery safety and underscores the need for further research to address safety challenges in emerging battery technologies.