Functional Description - Coolant Heater

The BPCM tries to maintain the high voltage battery pack cells at an optimal temperature to maximize driving and minimize charging time. This is accomplished in one of three operating modes:

Thermal equalization  - maintains consistent temperature inside the HV battery

• Low temperature active pump is forcing coolant through Low Temperature cooling system temperature differences
• Battery chiller is not active, only used as a pass through

Active cooling  - HV battery is too warm

• Low temperature active pump is active
• The Electric Air Compressor (EAC) is on forcing refrigerant from the A/C system through the battery chiller to help cool down or maintain a pre-set temperature within the HV battery pack
• Inter-loop heat exchanger is only used as a pass through

Active heating  - HV battery pack is too cold

• The combustion engine may start to heat the engine coolant
• Electric coolant heater may also be energized
• High temperature auxiliary pump is active
• Low temperature active pump is active