State-of-charge estimation of lithium-ion batteries based on ultrasonic detection

In order to characterize the state of charge of the lithium battery from the internal material properties of the lithium battery, this paper proposes a method of estimating the state of charge of the lithium battery based on ultrasonic non-destructive testing. First, this paper uses the ultrasonic flaw detector and other equipment to obtain the feedback signal of ultrasonic detection, then introduces the empirical mode decomposition (EMD) algorithm to eliminate the interference present in the ultrasonic feedback signal, and reconstructs the decomposed ultrasonic feedback signal to improve the continuity of the ultrasonic signal. Secondly, the Hilbert transform is performed on the ultrasonic signal. The maximum instantaneous energy of the ultrasonic signal is extracted with the ultrasonic energy entropy and the ultrasonic reception entropy as the characteristic quantity to measure the charge state of the lithium battery. Finally, this paper uses relevance vector regression to build a lithium battery state of charge estimation model. The experiments show that the method proposed in the thesis is practical and feasible, and has good estimation accuracy. The acoustic characteristics proposed in this paper provide a certain reference for subsequent related research.