Battery pack diagnostics for electric vehicles: Transfer of differential voltage and incremental capacity analysis from cell to vehicle level

• Published in: eTransportation (Amsterdam) Vol. 22; p. 100356
• Main Authors: Bilfinger, Philip, Rosner, Philipp, Schreiber, Markus, Kröger, Thomas, Gamra, Kareem Abo, Ank, Manuel, Wassiliadis, Nikolaos, Dietermann, Brian, Lienkamp, Markus
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2024
• Subjects: Battery aging; Battery electric vehicles; Battery pack diagnostics; Differential voltage analysis; Incremental capacity analysis; Lithium-ion battery; Battery aging; Incremental capacity analysis; Lithium-ion battery; Differential voltage analysis; Battery pack diagnostics; Battery electric vehicles
• ISSN: 2590-1168; 2590-1168
• DOI: 10.1016/j.etran.2024.100356

Aging of lithium-ion battery cells reduces a battery electric vehicle’s achievable range, power capabilities and resale value. Therefore, suitable characterization methods for monitoring the battery pack’s state of health are of high interest to academia and industry and are subject to current research. On cell level under laboratory conditions, differential voltage and incremental capacity analysis are established characterization methods for analyzing battery aging. In this article, experiments are conducted on the battery electric vehicles Volkswagen ID.3 and Tesla Model 3, examining the transferability of differential voltage and incremental capacity analysis from cell to vehicle level. Hereby, the vehicles are monitored during AC charging, ensuring applicability in real-life scenarios. Overall, transferability from cell to vehicle level is given as aging-related characteristics can be detected in vehicle measurements. Hereby, loss of lithium inventory is identified as the primary cause for capacity loss in the usage time of these vehicles. Both methods have limitations, such as data quality restrictions or vehicle specific behavior, but are suitable as diagnostics tools that can enable a vehicle level state of health estimation. •Diagnosis methods are proposed for battery packs in electric vehicles.•Differential voltage and incremental capacity analysis are analyzed for two vehicles.•Cell and vehicle data are measured to compare the transferability of both methods.•It is shown that aging related features can be extracted at the vehicle level.•From this, a state of health estimation for battery electric vehicles can be enabled. [Display omitted]