A multi-stage cascaded thermoelectrical cooler (TEC) package is used in conjunction with an air cooling system to control temperature of battery cells in a battery module such that the temperature differences stay within a predetermined range. Battery cells in the battery module are divided into one or more regular sections and one or more TEC enhancing sections. A regular section and a TEC enhancing section can use different types of battery cell holders to assemble the battery cells. TECs in the TEC package are integrated into each enhancing section, where each stage of the TEC package is attached to one or more battery cells in a different region of the enhancing section. A higher stage, which is more powerful in enhancing heat transfer and extracting heat from battery cells, is attached to one or more battery cells in a section closer to the air outlet. The TEC package is powered by a discharging convertor circuit of the battery module.