Abstract: A modular and on-demand battery thermal management system (BTMS) for an electric machine with a battery is disclosed. The BTMS may include one or more independently operable BTMS modules, where each BTMS module may be configured to cool a corresponding component of the electric machine, such as a particular battery pack. Each BTMS module, in turn, may include a plurality of BTMS units that cool coolant that is to be delivered to the components that are to be cooled within the electric machine. The individual BTMS units may be independently operable by a BTMS controller based at least in part on the cooling needs of the components to be cooled. The BTMS controller is also configured to select BTMS units to operate in a manner that maximizes the operating life and durability of the BTMS.