Detecting the internal short circuit (ISC) of Lithium-ion batteries is critically important for preventing thermal runaway. Conventional approaches mainly focus on ISC detection for dynamic load profiles, while the commonly seen float-charging scenarios with a high risk of ISC are rarely considered. Technical challenges arise from not only the lack of models describing battery dynamics at fully charged conditions but also the computational burden caused by the high number of series-connected cells in a battery pack. To address these issues, we here propose a simple and accurate method to quantitatively identify the leakage current of the battery with ISC, by checking the behaviors of the battery equalization system. Battery-in-the-loop experiments are carried out to verify the proposed method under a wide range of the short circuit resistances (∼20 to ∼500Ω), using both LiFePO4 and Li(NiCoMn)0.33O2 batteries with different aging degrees. The typical errors of the identified leakage currents can be well-bounded within ±1 mA, including the cases of using both passive and active balancing. The proposed method is completely model-free and, therefore, can be transplanted into low-cost embedded systems to support broader applications.
Bibliographical noteFunding Information:
This work was financially supported by Hong Kong RGC Postdoctoral Fellowship Scheme (PDFS2122-6S06), National Natural Science Foundation of China (52277222, 52277223, 5197713, 61433005), Hong Kong Research Grant Council (16208520), and Guangdong Scientific and Technological Project (2017B010120002).
© 2023 Elsevier B.V.
- Battery balancing
- Float charging
- Internal short circuit
- Lithium-ion battery management
- Model free