Experimental Study on Carbon Nanotube Heating for Li-Ion Batteries in Extremely Low-Temperature Environments

This study introduced and evaluated a new Carbon Nanotube (CNT) sheet-based method for battery temperature management, aimed at enhancing the performance of Li-ion batteries in subzero environments. This method addressed critical challenges such as startup failures, capacity loss, and the poor performance of the Li-ion battery in extreme cold conditions, particularly for industrial applications like forklifts operating at temperatures as low as −30 °C. Without CNT heating, the battery performance dropped significantly in low-temperature environments. At −20 °C, the battery delivered only 63.4% of its capacity, with minimal self-heating. At −30 °C, it failed almost entirely, shutting down after just 45 s. In contrast, CNT heating greatly enhanced performance. The CNT sheet quickly warmed the battery to 0 °C—within 97 s at −20 °C and 141 s at −30 °C—allowing it to recover up to 90% of its capacity. These improvements resulted in enhanced capacity and energy output compared to batteries without CNT heating, which suffered from severe performance losses, including a negligible capacity and energy output under −30 °C. It can be concluded that the CNT sheet-based approach provides superior thermal conductivity, rapid heating, and exceptional energy conversion efficiency, enabling extended battery life and enhanced operational reliability in subzero environments. Its scalability and affordability position it as a transformative innovation for industrial applications reliant on efficient battery performance in extreme cold environments.