In this research, the state of charge (SOC) in lithium-ion batteries is characterized using magnetic field imaging techniques. Initially, a three-dimensional model of a single cell is established, and the external magnetic field surrounding the cell is visualized based on obtained electrode current density. Subsequently, a comparison is made between the magnetic field imaging results of cells with different tab designs, considering the different current directions of the two types of cells. Finally, an investigation is carried out to explore the relationship between the SOC of lithium-ion batteries and the external magnetic field generated by the current distribution. The findings reveal a gradual decrease in the magnetic field as the SOC of the lithium-ion battery increases. This study provides a significant foundation for utilizing magnetic field imaging techniques to monitor and evaluate the SOC in lithium-ion batteries.

lithium-ion battery, state of charge, current density, magnetic field imaging, magnetic flux density