Exergy degradation and thermal dissipation in Li/FeS2 batteries under overvoltage stress

• Mathematical modelling of thermal behavior of lithium batteries under surge conditions. • Li-ion battery energetic and exergetic analysis under overvoltage conditions. • Heat dissipated by a lithium battery under overvoltage. • Chemical reactions taking place in a lithium battery under overvoltage. This study provides a pioneering thermodynamic and thermal analysis of Li/FeS 2 batteries subjected to overvoltage conditions. A comprehensive mathematical model was developed to simulate the thermal behavior of these batteries under overcharging, incorporating both voltage peaks and the state of charge. This approach facilitates a precise evaluation of the thermal energy generated under extreme operating conditions, thereby representing a significant advancement in understanding the thermal processes in these batteries. The experimental validation of the proposed model demonstrated its reliability, confirming that increased overvoltage leads to a considerable reduction in both energy and exergy efficiency due to heat generation and exergy loss. Furthermore, an increase in battery voltage results in a considerable rise in battery temperature, which has the potential to exceed safety limits. This can have a detrimental effect on battery performance and lifespan. Specifically, an increase in voltage from 5 V (V) to 10 V resulted in a 1.4 % reduction in exergy destruction and a halving of energetic efficiency. This finding suggests that the battery was operating well below its optimal efficiency. Moreover, the study examined the thermal and exergonic behavior of Li/FeS 2 batteries in both series and parallel configurations. In series, an increase in voltage resulted in trends analogous to those observed in individual batteries. Specifically, the cell nearest to the power source dissipated more heat and exhibited higher efficiency compared to the cell further from the source. Conversely, in parallel configurations, the battery nearest to the power source exhibited only a slight decrease in heat dissipation (2.2 %), but experienced a significant reduction in generated entropy (80.4 % and 80.3 %) and exergy destruction. The second battery in parallel demonstrated behavior consistent with that observed in series configurations, indicating that parallel configurations exhibit reduced efficiency under overvoltage conditions in comparison to series configurations. This investigation constitutes the initial comprehensive inquiry into the thermal and exergonic behavior of lithium-pyrite batteries under overvoltage conditions. The investigation establishes a foundation for future research endeavors aimed at optimizing battery performance, safety, and thermal management. The methodology proposed for quantifying energy and exergy is of crucial importance for developing strategies to improve energy efficiency, extend battery lifespan, and reduce environmental impact. These advances contribute to the advancement of sustainable energy storage systems.