Thermal management of an electrochemical cell by a combination of heat transfer fluid and phase change material

A device comprising:

• a. an inlet for receiving a heat transfer fluid;
• b. one or more electrochemical cell compartments for receiving one or more electrochemical cells;
• c. one or more thermal energy storage material compartments containing one or more thermal energy storage materials;
• and
• d. one or more heat transfer fluid compartments for flowing the heat transfer fluid through the device;
• wherein the device is a temperature regulating device,
• the space between the one or more heat transfer fluid compartments and the one or more electrochemical cell compartments includes one or more regions that are substantially free of the thermal energy storage material;
• and
• the space between the one or more heat transfer fluid compartments and the one or more thermal energy storage material compartments includes one or more regions that are substantially free of an electrochemical cell;
• so that the heat transfer fluid compartment is in direct thermal communication with both the thermal energy storage material compartment and the electrochemical cell compartment such that the contact between the one or more heat transfer fluid compartments and the one or more thermal energy storage material compartments has an area ATESM and the contact between the one or more heat transfer fluid compartments and the one or more electrochemical cell compartments has an area AEC wherein the ratio of ATESM/(ATESM+AEC) is greater than 0.1.