Investigation of the thermal performance in lithium-ion cells during polyformaldehyde nail penetration

The nail penetration test on lithium-ion cells with a tungsten steel nail can cause significant heat sinking to the nail. In this work, a polyformaldehyde nail with both low thermal conductivity and low electrical conductivity is proposed to conduct the nail penetration test to study the thermal response. Meanwhile, a 3D electrochemical–thermal model is developed to predict the thermal behavior of lithium-ion cells during nail penetration tests. Two typical modes (recovery mode and non-recovery mode) of voltage response are observed and illustrated in polyformaldehyde nail penetration tests. The present results demonstrate that Al–Cu short dominants the four internal short-circuit modes in polyformaldehyde nail penetration tests. It can be concluded that net heat absorbed by the cell in polyformaldehyde nail penetration modeling is more than that in tungsten steel nail penetration modeling, causing the higher temperature rise of lithium-ion cell in nail penetration tests with the tungsten steel nail than that of polyformaldehyde nail. The present study provides an ideal alternative to solve the heat sinking to the nail in the nail penetration tests effectively.