Evaluation of lithium-ion batteries with different structures using magnetic field measurement for onboard battery identification

When Original Equipment Manufacturer (OEM) lithium-ion batteries (LIBs) in electric vehicles are substituted with lower-quality non-OEM batteries, instances of non-OEM battery-related fires and other incidents have been documented in a report. This underscores the need for a technology capable of authenticating (LIBs) to avert such incidents, especially in electric vehicle applications. Current identification technologies, such as barcodes and integrated circuit (IC) chips, are in place; however, these technologies can be susceptible to counterfeiting through duplication or replacement. Therefore, this study focused on the magnetic field around the LIBs themselves. In previous studies, current distribution analysis of LIBs using magnetic sensors has been conducted as a nondestructive failure determination method. However, this method has not yet been applied to battery identification. This study proposes the identification of individual LIBs through magnetic analysis. Magnetic fields of prismatic LIBs with varying internal structures were measured, and differences between the results were evaluated using theoretical equations and simulations. Consequently, distinct magnetic fields were measured on the short sides of the cell for each sample. This distribution was attributed to the difference in the shape of the current collector. Even when using two cells connected in series to simulate a LIB module, a similar trend was observed in the magnetic field distribution. Magnetic sensors were utilized to measure the magnetic field characteristics of different internal structures of LIBs and reproduce relative relationships in the simulations. These results suggest that individual LIBs can be distinguished by strategically positioning magnetic sensors. The proposed system could serve as fundamental technology for identifying individual battery modules.