Frontier Technologies and Development Trends
in Automotive Thermal Management
Water Cooling is the Main Cooling Method for Power Batteries
Liquid cooling is the mainstream technology for power battery cooling. The battery's range is closely related to the ambient operating temperature, so temperature control is the core of thermal management for the three-electric system. Based on the management method, power battery pack cooling (temperature control) mainly includes four categories: natural cooling, air cooling, liquid cooling, and direct cooling. Air cooling suffers from poor consistency and difficulty controlling the cooling effect, while direct cooling with refrigerant is more challenging. Therefore, liquid cooling remains the primary approach for battery cooling.
1. Air Cooling
Air flow allows for convective heat exchange between the battery pack and the outside air. This cooling method can be categorized as natural cooling or forced air cooling with a fan. The cooling medium is air.
Advantages:
1. Low cost
2. Lightweight and low energy consumption
3. Highly commercializable
Disadvantages:
1. Low heat dissipation efficiency
2. Requires a large layout space
Due to the greater specific heat capacity of liquids, cooling efficiency is higher. Liquid cooling plates and cooling tubes are placed on the battery pack, or the battery pack is directly immersed in it, using a coolant such as water-ethylene glycol for heat exchange. The medium is a coolant such as water-ethylene glycol.
Advantages:
High heat dissipation efficiency
Good temperature distribution uniformity
Highly commercializable
Disadvantages:
Complex structure and high cost
Heavy installation weight
Risk of leakage
3. Direct Refrigerant Cooling
The refrigerant gas is condensed into a high-temperature, medium-pressure liquid by a compressor and a front-end condenser. The refrigerant then evaporates by absorbing heat from the cabin air conditioning evaporator or the cold plate within the battery pack. The refrigerant then returns to gas through the expansion valve and returns to the compressor, completing the cycle. The medium is a refrigerant (R134a, R744, etc.)
Advantages:
Good cooling performance
Good temperature distribution
Fast response
Disadvantages:
High cost
High technical barriers
Not yet commercialized
