A Methodology to Develop 25-kWh Battery Pack Model with Its Cooling System for off-highway application

This study presents a methodology to develop a new 25kWh battery pack for off-high application. Initially an enclosure space is extracted from tractor model maintaining minimum space with adjacent components. Based on available space, various combination of cell form factors and different cell chemistries are evaluated considering operating ambient temperature range (-20 to 45 deg C) and charge/discharge rate 1C. Cylindrical NMC type cell with indirect cooling system fulfils all our technical requirements. However, complete battery pack thermal simulation is carried out for ensuring battery pack safety and limited deterioration with different discharge rate and wider temperature range. The battery pack model contains multiple cells, bricks, and modules with numerous coolant pipes and flow channels. Cell characterization experimental data is used for estimating cell thermal capacity and IR behaviour. Battery pack model is tested with difference Charge/discharge rates. Five thermocouples, pressure, and coolant flow sensors are installed on the different battery cells, bricks, and modules to capture the time-series thermal and electrical performance changes. These data are used to validate the integrated battery pack and its TMS cooling circuit. It is observed correlation above 90% for temperature, pressure and velocity between simulated and experimental values.