Design of Rapid Battery Pre-test Diagnostic Process

Abstract

WIith the increasing aging of electric vehicle batteries in large quantities, rapid pre-test diagnosis of power battery modules and screening of defective batteries have become market demand. This paper was based on the portable fast battery diagnostic instrument, which quickly checked the lithium iron phosphate battery packs with different degrees of aging to determine whether the battery management system and the battery modules were connected properly. Furthermore, the constant current discharge curve of the battery was analyzed, and the internal resistance of each single cell in the battery module was obtained, thereby characterizing the difference in the aging degree of different single cells. Finally, the same battery module was tested using a portable fast battery diagnostic device. The verification found that after the battery management system and the single battery connection problem were eliminated, the portable device obtained the same result under different detection conditions, and the battery module was aged. The single cell was judged to be a problematic single cell because the internal resistance was too large and the open circuit voltage was too low. The portable device has low cost, simple operation, convenient and fast, and is suitable for rapid troubleshooting and internal resistance detection of the battery module in the field, and does not affect the life of the battery pack itself. The results of the fast battery diagnostic process are reliable and can provide a reference for the promotion of the rapid diagnosis of power batteries.