Electric Vehicle Cooling Components
The cooling components are designed to keep the eAxles and high-voltage batteries at their optimum operating temperatures. This results in the most efficient delivery of power and less component stress.
The central components of the cooling system are the radiator assembly, surge tanks, electric refrigerant compressor, heaters, and the electric pumps; the pumps circulate the coolant through all of the connected components.
Radiator: The radiator is placed in front of the front box, connecting to the other cooling components. It helps to eliminate excess heat from the eAxle and high-voltage batteries. It includes a liquid coolant, hoses to circulate the coolant, fans and a thermostat that monitors the coolant temperature.
Surge Tank: The surge tank provides storage space for reserve coolant, expansion space for heated coolant, and de-aeration space. When coolant in the radiator runs low, reserve coolant stored in the surge tank flows from the tank, through the fill hose, to the water pump.
Electric Coolant Pump: An electric coolant pump is powered by the low-voltage system. It pressurizes the coolant to ensure the coolant circulates in the cooling system.
Positive Temperature Coefficient (PTC): The PTC heaters provide efficiency and safety to the electric vehicle heating system. This heater uses a PTC semiconductor as the heating element. The PTC semiconductor drastically increases its electrical resistance at temperatures above a certain level and is able to maintain a constant heating element temperature during load and supply voltage changes. For this reason, the risk of the heating element’s overheating or catching fire is minimal, even under unexpected boil-dry conditions due to the loss of hot water. Moreover, the heat generation capacity is nearly constant over a wide range of battery voltage fluctuations.
Chiller: The chiller transfers the thermal energy from the battery coolant loop to the vehicle’s refrigerant loop to maintain optimum battery temperatures. The chiller has an electronic expansion valve that regulates the refrigerant flow into the chiller.
Electric Refrigerant Compressor (eRC): The electric refrigerant compressor is the heart of the cooling cycle. The cycle begins when the compressor draws in cool, low-pressure refrigerant gas from the low side of the system. The motor-driven compressor’s sole function is to squeeze the refrigerant, raising its temperature and pressure so that it exits the compressor as a hot, high-pressure gas.
3/2 Valve: The three by two valve has one inlet, and two outlet options: A or B. It lets the coolant flow to either the radiator or the active cooling or heating modes.