Thermal management system for fuel cell vehicle having multiple fuel-cell stacks

A vehicle comprising:

• first and second fuel-cell stacks;
• a first coolant circuit including conduit arranged to circulate coolant through the first fuel-cell stack;
• a second coolant circuit including conduit arranged to circulate coolant through the second fuel-cell stack;
• a heater in fluid communication with at least the first coolant circuit;
• a valve arrangement configured to proportion a flow of coolant between the first and second coolant circuits, the valve arrangement including an isolation position in which the first and second circuits are not in fluid communication and at least one mixing position in which the first and second circuits are in fluid communication;
• and
• a controller programmed to:
• in response to coolant of the first circuit being less than a first threshold, command the isolation valve assembly to the isolation position and command the heater ON, and
• in response to coolant of the first circuit exceeding a second threshold, command the isolation valve assembly to the at least one mixing position and command the heater OFF.

A vehicle comprising:

• first and second fuel-cell stacks;
• a first coolant circuit including conduit arranged to circulate coolant through the first fuel-cell stack;
• a second coolant circuit including conduit arranged to circulate coolant through the second fuel-cell stack;
• a heater in fluid communication with at least the first coolant circuit;
• a valve arrangement configured to proportion a flow of coolant between the first and second coolant circuits, the valve arrangement including an isolation position in which the first and second circuits are not in fluid communication and at least one mixing position in which the first and second circuits are in fluid communication.