In the rapidly developing field of battery technology, is it desirable to perform diagnostics on battery cells by non-destructive and non-contact measurements. We demonstrate the use of atomic magnetometry to detect states of battery charge . We do so by creating a map of the weak induced magnetic fields around a commercial Li-ion battery cell as a function of its state of charge. We also study the effect of mechanical defects in the battery on its internal currents and magnetic susceptibility. The high sensitivity afforded by the system also revealed minute-scale weak transient internal currents that persist after discharging.
 Yinan Hu, Geoffrey Z. Iwata, Mohaddese Mohammadi, Emilia V. Silletta, Arne Wickenbrock, John W. Blanchard, Dmitry Budker, and Alexej Jerschow, Battery Diagnostics with Sensitive Magnetometry, arXiv:1905.12507 (2019).