Developing a New Test Method for Lithium-Ion Battery FastCharging under Magnetic Fields and Sub-Zero Temperatures

Lithium-ion batteries (LIBs) experience a decline in performance at low temperatures, presentinga significant challenge for their use in demanding environments, such as military operations. Incollaboration with Swedish Defence Research Agency (FOI), this project explores if there is anyadvantage in applying a magnetic field over LIBs when charging in sub-zero temperatures andfast-charging at room temperature. A custom-built setup was assembled, consisting of an elec-tromagnet, custom-constructed cooling system, and electrochemical measurement instruments.Batteries were cycled under both room temperature and −10.5◦C under three different magneticfields strengths (0 T, 0.1 T, 0.18 T). The results indicate that a moderate magnetic field (0.1 T)could to some degree, enhance the charging capability under cold conditions, likely as a resultof the magnetohydrodynamic (MHD) effect, which enhances ion mobility. In contrast, a strongermagnetic field (0.18 T) appeared to reduce performance, suggesting that excessive electrolyteconvection or flow disturbance could have a negative impact on charging capacity. Under roomtemperature and fast charging conditions, a field of 0.1 T showed a clearer improvement in perfor-mance at higher C-rates. This supports the hypothesis that the internal resistance can be reducedby applying an magnetic field during high-rate operation. While results are preliminary, the studypresents a validated experimental setup and valuable insights for further investigation into mag-netic field assisten battery operations in cold temperatures.