Rapid safety screening realized by accelerating rate calorimetry with lab-scale small batteries

The increasing energy density and size requirements have necessitated the establishment of reliable safety technologies for rechargeable batteries. In particular, understanding and controlling thermal runaway, an uncontrollable heat generation from continuous exothermic reactions in batteries, is essential for developing high-safety batteries. However, comprehensive safety evaluations at the full-cell level are limited by size requirements (greater than the ampere-hour scale) for performing accelerating rate calorimetry tests that can provide critical information on heat generation during thermal runaway. Further, efficient safety screening is difficult because of substantial quantities of battery materials and costly manufacturing processes. Here we designed cylindrical pouch-type small batteries (~21 mAh, ~0.1 g of cathode active materials) that are highly susceptible to heat generation, thus allowing us to perform full-cell-level accelerating rate calorimetry tests on a laboratory scale. This enables rapid safety screening and early-stage feedback for battery design, which can help accelerate the development of high-safety batteries. A full-cell-level accelerating rate calorimetry test requires large batteries, leading to high costs. The authors design small cylindrical pouch cells (~21 mAh, ~0.1 g cathode material) for lab-scale accelerating rate calorimetry tests, enabling efficient safety screening and faster high-safety battery development.