Thermal and overcharge abuse analysis of a redox shuttle for overcharge protection of LiFePO4

• Published in: Journal of power sources 2014-02, Vol.247, p.1011-1017
• Main Authors: LAMB, Joshua, ORENDORFF, Christopher J, AMINE, Khalil, KRUMDICK, Gregory, ZHENGCHENG ZHANG, LU ZHANG, GOZDZ, Antoni S
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.08.044

This work investigated the performance and abuse tolerance of cells protected using the redox shuttle 1,4-bis(2-methoxyethoxy)-2,5-di-tert-butylbenzene. The thermal efficiencies were evaluated using isothermal battery calorimetry. Cells containing the overcharge shuttle were observed to reach a steady state value of approximately 3.8 V, with a small variance in direct proportion to the applied current. In all cases the heat output from the cells was measured to reach similar to 90% of the total input power. The heat output was also measured using isothermal calorimetry. At higher rates of overcharge, the data shows that the cell containing the shuttle rapidly reaches a steady state voltage, while the temperature increases until a moderately high steady state temperature is reached. The control cell meanwhile rapidly increases in both applied voltage and cell temperature until cell failure. Two cells in series were taken deliberately out of balance individually, then charged as a single pack to observe the time needed to bring the cells into balance with one another.