Lithium ion battery lossless fast charging method and system based on multi-frequency sine nonlinear characterization

The invention provides a lithium ion battery lossless fast charging method and system based on multi-frequency sine nonlinear characterization, and relates to the technical field of battery charging optimization. According to the lossless fast charging method, non-linear characterization of the lithium ion battery is carried out based on a dynamic in-situ multi-frequency sine impedance spectrum; the frequency domain voltage nonlinear response of the lithium ion battery is decomposed into even order and odd order responses to obtain a lithium precipitation boundary when the battery is charged; and designing a lithium ion battery lossless fast charging strategy based on the lithium precipitation boundary: dividing lithium ion battery charging into a pre-charging stage, a fast charging stage and a floating charging stage, and executing a preset charging strategy in each stage. The lithium precipitation boundary is determined based on the dynamic in-situ multi-frequency sine impedance spectroscopy, so that lithiu