Randles Circuit Parameters Set Up for Battery Simulations in LS-DYNA ®

A multi physics model for battery abuse was recently introduced in LS-DYNA. This model predicts coupled mechanical, thermal, electrical and electro-chemical responses. The complex electro-chemical behavior is described by simple equivalent circuits, called “Randles” circuits. Each Randles circuit connects two vis-à-vis nodes of the positive and negative current collector layers and consists in a State-OfCharge (SOC) dependent voltage source, an internal resistance and a resistance-capacitance (RC) loop. The choice of the values of the circuit components in the LS-DYNA cards is let to the user and strongly depends on the battery cell. This paper thus proposes a procedure to choose with precision the Randles circuit components values from simple voltage and current measurements on the cell. The parametrization process is done by a parameter identification on these experimental coupled voltage/current measurements, such as Hybrid Pulse Power Characterization (HPPC) test results, in a single Randles circuit, representing the whole cell. The paper will present briefly the distributed Randles circuit model and the experimental tests before exposing one parameter identification method.