Experimental and numerical study of employing Potassium poly acrylate hydrogel for thermal management of 500 Wh cylindrical LiFePO4 battery pack. (15th September 2019) - Jannesari, Hamid
Highlights: Potassium poly acrylate hydrogel is used as passive battery thermal management system. Employing hydrogel reduces maximum pack temperature by 10.9 °C for 3C discharge rate. Full filling of pack edges by hydrogel highly influences on temperature decreases. Hydrogel is a more effective strategy respect to the increase in distance between cells. Cell density and specific heat capacity play significant role on pack temperature. Abstract: One of the main challenges of employing lithium-ion batteries specially in large-scale applications is overheating due to the heat generation. In this work, the effect of using Potassium Polyacrylate, a superabsorbent hydrogel, on decrease in the maximum temperature inside a 500 Wh industrial pack consisting of 38, 120 cells is studied. Experiments are performed for 1C and 2C discharge current rates. Due to experimental limitations, results for discharging battery pack at 3C rate are obtained by numerical simulation. Heat source term in simulation part of work is obtained based on the experimental data for different discharge rates. It was found that inserting hydrogel inside the battery pack leads to 3.9 °C, 7.5 °C and 10.9 °C decreases in the maximum temperature for 1C, 2C and 3C discharge rates, respectively. In addition, results revealed that the decreases in the temperature of the battery pack is considerably influenced by full filling of hydrogel at points near the edges. Moreover, the effect of distance variation between cells on the temperature distribution of the battery pack is numerically studied. The results demonstrated a significant advantage to employ hydrogel for controlling battery pack temperature compared to increasing distance between cells. Finally, to compare the effect of different parameters on the maximum temperature of battery pack, the sensitivity analysis was performed. Results showed that cell density and specific heat capacity play significant role on the pack thermal behavior.