Failure analysis of lithium iron phosphate batteries under squeezing conditions

This study investigated the influence of various factors on the safety performance of lithium iron phosphate (LFP) batteries by examining the internal structural changes under squeezing conditions. Squeezing tests were conducted on square LFP batteries, and deformation and failure mechanisms were analyzed using industrial computed tomography (CT) scan technology. The results reveal that the deformation of the battery decreases as the state of charge (SOC) value increases. Furthermore, increasing squeezing pressure leads to increased deformation and raises the risk of an internal short circuit. Additionally, compared to the front squeezing direction, the battery exhibits more significant deformation in the lateral direction. The SOC value has a minor effect on voltage, whereas high squeezing pressure or significant deformation can lead to a substantial voltage drop, potentially followed by a partial or complete recovery to a stable state. Moreover, within a specific range, squeezing exerts minimal influence on the surface temperature of the battery. These research findings provide valuable insights for optimizing the design and safety assessment of LFP batteries.