Air-Cooled Battery-Pack Thermals and Capacities Under Various Operating Temperatures and Processes

Battery packs can be used to provide emergency power during power outages to allow ride-through until restoration of backup power or alternatively, provide sufficient uptime to allow the system to backup or save data and records and enact a safe shutdown. Using battery packs also contributes to a more robust power design and higher immunity to power line disturbance. Thermal management of large battery packs remains a challenge due to complex heat transfer mechanisms and pathways. In this paper, we investigate the thermal profile within a battery pack during the critical charging and discharging process as well as the impact of operating environments on battery capacities. Thermocouples were installed on multiple batteries along the air flow stream as well as at several points on a single cell to investigate pack-level thermal management and heat distribution within a single cell respectively. Experiments found a large amount of heat was generated during the shorter discharging process compared to the longer battery charging process. Charge capacities of four air cooled battery packs were measured at various temperatures during the charging and discharging process and were found to be reduced at both lower and higher operating temperatures.