Drive Motor Battery Cooling Description

Drive Motor Battery Cooling Description

Cooling System Description and Operation

This vehicle is equipped with three fully independent cooling systems. The power electronics cooling system is dedicated to cooling the battery charger and the power inverter module. The battery cooling system is dedicated to cooling and heating the high voltage battery. The engine cooling system is dedicated to cooling the engine and providing heat to the passenger compartment.

Battery Cooling System Description and Operation

The battery cooling system uses a radiator, two 12 volt pulse width modulated (PWM) radiator fans, a 12 volt coolant pump, a refrigerant/coolant heat exchanger (chiller) and a coolant flow control valve to cool down the high voltage battery. There is also a high voltage heater inside the battery to heat the coolant entering the battery when needed. The hybrid/EV powertrain control module 2 monitors the battery coolant temperature, battery cell temperature, refrigerant temperature and refrigerant pressure. The hybrid/EV powertrain control module 2 determines how much battery cooling or heating is required and turns on the coolant pump, positions the coolant flow control valve and depending on what is required will signals the Engine Control Module (ECM) to operate the radiator fans, request the A/C Compressor Module (ACCM) to turn on the high voltage A/C compressor, or turn on the high voltage heater. The engine control module uses this request and other vehicle inputs to decide if and what speed the cooling fans should operate. The engine control module sends the cooling fan command to the hybrid/EV powertrain control module 2. The hybrid/EV powertrain control module 2 sends the signal to the cooling fans to operate and at what speed. The battery cooling system could be activated when the vehicle is on and during charging.

If the vehicle is in Charge Mode and the hybrid/EV powertrain control module 2 requests the cooling fans to operate, if the engine control module is not awake, the hybrid/EV powertrain control module 2 will control the cooling fans. If active cooling is needed, the engine control module wakes up to operate the air conditioning control module and then the engine control module is the master controller for the fans.

The battery cooling system circulates a pre-mixed Dexcool(R) which is a 50/50 mixture of Dex-cool and de-ionized water. De-ionized water is required for high voltage isolation and to prevent corrosion from effecting heat sink performance. Always use pre-mixed coolant and never use tap water in the battery coolant system.