The United States DOE has identified extreme fast charging (XFC, i.e., recharge in 10 min or less at a charging rate of 6C and above) as a critical challenge that must be overcome in order to achieve widespread adoption of EVs. INL, as one of partners in the DOE-sponsored eXtreme Fast Charge Cell Evaluation (XCEL) program, identifies the bottlenecks of applying such high rates to batteries and the relavent implications to performance, life, and safety. Understanding of the aging implications of XFC is crucial to optimize material, electrode, and cell designs and operating conditions to achieve XFC targets. The XCEL program has six major research thrusts—namely, cathode, charging protocol, anode design, heterogeneity, heat generation and Li-plating detection. INL researchers lead the cathode and charging protocol thrusts and provide key support to anode design, heat generation, electrolyte thrust, and heterogeneity thrust. Noteably, the INL's Advanced Electrolyte Model (AEM) has been instrumental in deriving formulations for new electrolytes for XFC applications. With these new formulations, AEM provides genomic-level property sets that cover ionic transport, thermodynamics, ion solvation kinetics, surface charge effects, electrolyte permeation, and other metrics. The latest publications on enabling XCEL can be found below.
A recent article
Extended Cycle Life Implications of Fast Charging for Lithium-Ion Battery Cathode led by Tanim et al. reports the complex evolution of Lithium-ion battery cathode degradation at multiple length scales under extended extreme fast charging, i.e., charging in 10 to 15 min at rates up to 9C and cycled up to 1000 times. Cathode aging issues remain minimal in early cycling, but begin to evolve differently in later cycling, resulting in complex and convoluting effects.
INL research provides key understanding on the bottlenecks of extreme fast charging (charge in 10 to 15 min at >6C and above) and identifying ways to enable XFC.
Research Contact: Tanvir Tanim - Phone: (208) 526-5713 - Tanvir.Tanim@inl.gov
Eric Dufek - Phone: (208) 526-2132 - Eric.Dufek@inl.gov