Soo-Seok Choi

Modeling and Real Time Estimation of Lumped Equivalent Circuit Model of a Lithium Ion Battery

In this paper, a real time estimate of a battery model is proposed. The existing impedance model is accurate in predicting the behavior of a battery. However, it is complex and not applicable for real time applications. Also, it requires much time and cost to obtain the parameters of the model. A simple lumped circuit model is presented. The parameters and states (overvoltages) of the battery are estimated with a filtering technique and system identification theory. It is verified through simulations and experiments that the proposed method is in good agreement with the dynamic characteristics of the battery, regardless of the conditions of the battery, and the estimated overvoltages are given physical meanings through a comparison with an impedance model with complex RC ladder circuits

Evaluation of mechanical properties and finite element modelling of Ti/Al clad sheet

Abstract A clad sheet is a metal coated laminate with various advantages such as strength, workability, corrosion resistance and economic efficiency. However, measurement of the mechanical properties of clad sheets is difficult because of different yield strengths, bending phenomena and other properties of their multiple components. This study investigated the characteristics of a Ti/Al clad sheet and applied the findings to finite element analysis (FEA). Tensile testing, optical microscopy and the Vickers hardness test were first carried out experimentally. Then, a numerical method for obtaining a stress–strain curve using the relationship between yield stress and hardness is proposed. The method measures mechanical properties in a timely and cost efficient way.