Methods and systems for estimating the core temperature of at least one cell in a battery at the termination of a rest period. The method for estimating the core temperature of the cells in a battery includes measuring the surface temperature of the cells, obtaining the estimated core temperature of the cells, obtaining the time required for the surface temperature and the estimated core temperature of the cells to converge, and estimating the core temperature of the cells based on the measured surface temperatures, the obtained estimated core temperature, and the obtained time. The system for estimating the core temperature of the cells in a battery includes at least one sensor configured to receive temperature information and a control system in signal communication with the sensor, wherein the control system comprises a memory device and a controller.