Non-destructive visualization of short circuits in lithium-ion batteries by magnetic field imaging system

To develop a high-density and long-life lithium-ion battery, a technology is needed that allows non-destructive visualization of the spatial distribution of deteriorated parts after cycle test. In the present study, we measured the distribution of the magnetic field leaking from the lithium-ion battery during its operation. Based on the measurement results, we evaluated the current density distribution inside a battery using the electric current reconstruction process. With respect to the changes in an internal state of the lithium-ion battery associated with cycle deterioration, we successfully visualized the spatial changes in the conductivity distribution inside the lithium-ion battery.