NOVELTY - The method involves determining temperature in an energy storage module, where the energy storage module includes an array of energy storage cells (30) and phase change material provided in thermal contact with a coolant passage (350) and the energy storage cells. The temperature is compared to first and second threshold. Coolant flow is changed through a coolant passage based on the comparison by increasing the coolant flow through the coolant passage when the temperature reaches the second threshold and decreasing coolant flow when the temperature reaches the first threshold.    USE - Method for cooling an energy storage module in industrial applications/heavy duty mobile applications such as hybrid vehicles, under-hood applications and electric drive vehicles, and stationary power generating applications i.e. generator set enclosure applications, in harsh environments i.e. desert environments.    ADVANTAGE - The method enables conducting and storing heat by the phase change material from the storage cells to allow the energy storage module to be used at higher power levels and at higher ambient temperatures, so that phase change material (PCM) can be designed such that the heat from most charge/discharge cycles and ambient temperatures can be stored and dissipated without need for additional cooling, thus saving energy needed to run a pump and valves. The method allows the phase change material to work well and eliminating need for circulation of the coolant if either the heat generated by the storage cells or ambient temperature does not exceed melting temperature of paraffin wax, while managing shock and vibration problems in an effective manner.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a system for managing thermal condition of an energy storage module.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a structure illustrating a method for cooling an energy storage module.    Energy storage cells (30)    Block (330)    Cylindrical voids (340)    Coolant passage (350)