Mechanical, Thermal, and Short-Circuit Responses of Different Sizes and Capacities of Batteries under In Situ Compression

In this study, we investigated the real-time deformation, temperature rise, voltage drop, and failure modes of batteries during compressive loading via an in situ compression experimental platform employing three-dimensional digital image correlation (3D-DIC) technology. We found that weak points at the annular groove structure between the end-cap and shell act as triggers for battery damage due to stress concentration. The damage leads to a short circuit and thus a temperature increase. A small-sized battery has a greater ratio of surface area to volume and thus benefits from heat dissipation. However, a battery with a larger volume possesses better stress tolerance but worse ductility, making the electrodes more prone to cracking and accelerating capacity decay. Theoretical analysis identifies the mechanisms behind the faster capacity degradation of high-capacity, large-sized batteries during cycling from a mechanical performance perspective. These findings provide valuable design insights and theoretical support for researchers and engineers in the field.