An SMPS-Based Lithium-Ion Battery Test System for Internal Resistance Measurement

A switching mode power supply (SMPS)-based lithium-ion (Li-ion) battery test system (BTS) is proposed to meet the increasing demands of tests in battery research. To improve the flexibility, while building the BTS with low cost and high reliability, an SMPS is employed as a charger/discharger, combined with a digital-to-analog hybrid control system to regulate its output voltage and current. Based on the BTS, two dc internal resistance (DCIR) measurement methods are designed, and a battery state classification method based on the DCIR cluster analysis with similarity as the judgment basis is proposed. An experimental prototype is developed to verify the feasibility of the proposed BTS and methods. The results show that the BTS possesses excellent voltage and current regulation capabilities for charging, discharging, and grid energy recovery. The internal parameter extraction method enables obtaining DCIR and other parameters with high accuracy. The online measurement method allows automatic acquisition of real-time DCIR and its variation trend without affecting the charging, which greatly improves the measurement efficiency. The proposed hierarchical clustering method based on DCIR effectively achieves the classification of battery states with excellent practicality and robustness.