Lithium ion battery is generally used in mobile devices for its advantages such as easy downsizing and weight saving due to high energy density. If there is the short circuit point in the battery, the abnormal heating occurs because of the high energy density. Therefore, it is necessary to identify the short circuit part in Lithium ion battery. However, it is difficult to clarify the micro abnormal part in the battery by diagnosis imaging such as X-ray inspection. In this study, a new technique of nondestructive detection of short circuit part has been developed by using inverse analysis of the magnetic field around the battery. This technique enables detection of the short circuit part by estimating the current density in the battery from data of the magnetic field around the battery. To verify the effectiveness of the technique, numerical simulations were carried out for specimen models with several slit modeled short circuits. The result shows that the technique could detect the internal short circuit of the battery.
