Life Extrapolation Model for Lithium-ion Battery with Accelerated Degradation Test

Battery life estimation is a key part for lithium cells for a long cycle life. The purpose of this paper is to develop a life extrapolation model for evaluating the lithium-ion battery cycle life with accelerated degradation test (ADT) data. An ADT is carried out including lithium-ion battery cells discharged with different current. The ADT data are used for parameterization with the accelerated model and distribution model. The lifetime of normal working condition is obtained by the fusion of accelerated model and accelerated data. To improve ability for life extrapolation, the proposed method is modeled with uncertainty expression by confidence lower limits and confidence lower limits for the reliability for the extrapolated life. Finally, extrapolation trajectory with uncertainty expression is obtained and the extrapolation result indicates that the proposed model can provide more accurate estimates with life extrapolation. In addition, the remaining useful life corresponding to any discharge current can be also calculated.