The effect of a new design preheating unit integrated to graphite matrix composite with phase change battery thermal management in low-temperature environment: An experimental study

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It is critical to eliminate the difficulties of using li-ion batteries at low-temperature environments for acceptable performance by preheating strategy. Hence, an experimental study is reported on the performance of a new hybrid preheating unit integrated to graphite matrix composite with phase change thermal management for small-scale li-ion module exposed to low-temperature conditions. The graphite matrix with 75 g/L is saturated with organic paraffin. Cartridge heating is mounted in graphite matrix composite with phase change for preheating period. The performance tests of the li-ion module for a low-temperature environment (T = −15 °C) are conducted at 1C and 1.6C discharge rates. For the low-temperature performance of graphite matrix composite with and without preheating, temperature history, discharge, and energy capacity variations are reported comprehensively. The results show that the proposed preheating unit integrated to graphite matrix composite with phase change has an important contribution on operating temperature, discharge and energy capacity values for better life span and safety compared to the non-preheating case for extreme low-temperature environment. The PCM/graphite matrix with preheating is more effective for higher discharge rates (1.6C). For the non-preheating case at 1.6C-rate, 100% capacity loss is occurred depending on instant voltage drop at T = −15 °C. However, the capacity loss is decreased to 22% with hybrid preheating of the li-ion module. The energy capacity value of the li-ion module reaches 44Wh at a higher discharge rate (1.6C-rate), while energy capacity is 0 Wh in the non-preheating case. Moreover, heating efficiency is obtained as 58%.