The transition from traditional fuel vehicles to modern new energy vehicles has significantly impacted the complexity of vehicle thermal management systems. Originally simple, these systems have evolved into intricate structures, progressing from standalone modules to integrated systems engineering.
Traditional thermal management primarily involves air conditioning and powertrain systems. In contrast, new energy vehicles incorporate the power battery system into the thermal management scope, marking a shift towards ‘new’ thermal management.
This article focuses on key components within both traditional and new thermal management systems. In traditional systems, we highlight the condenser, evaporator, radiator, oil cooler, and intercooler. For new thermal management, the spotlight is on the battery cooling plate.
The condenser is an integral component of the vehicle’s air conditioning (A/C) refrigerant circuit. It connects to the A/C compressor and the receiver-drier via copper and aluminium pipes. Typically installed in front of the car’s radiator, it often shares a cooling fan with the radiator. Based on the type of coolant used, condensers can be classified into four types: water-cooled, air-cooled, water-air cooled (including evaporative and spray types), and those cooled by refrigerant evaporation or other process media.
During operation, the condenser cools high-pressure, high-temperature refrigerant into a high-pressure, low-temperature liquid. This liquid then passes through a capillary tube, vaporising into the evaporator to continue the cooling cycle. As this process releases heat, the condenser usually operates at a high temperature, categorising it as a type of heat exchanger.
Conversely, the evaporator, located behind the cabin air filter, absorbs heat, resulting in a surface temperature drop. When the vehicle’s fan blows air over the evaporator, the air is cooled, generating cold air to provide a comfortable environment inside the car.
Advantages:
Quickly releases heat from the refrigerant to the external environment.
Improves the efficiency of the air conditioning system.
Made with high temperature-resistant aluminium or copper materials.
Maintenance and cleaning are relatively simple.
Helps maintain a comfortable temperature inside the vehicle.
Disadvantages:
Easily damaged by road debris or impact.
Needs regular cleaning to maintain effectiveness.
Dirt affects cooling efficiency.
Performance is reduced at very high or low temperatures.
Installation or replacement can be complicated.
The radiator is a crucial component of the engine, primarily comprising the radiator core, water pipes, cooling fan, upper tank, and lower tank, all connected by rubber hoses. The upper tank links to the radiator below via water pipes. Hot water flows from the upper tank to the lower tank, cooling as it descends. The cooling fan, driven by the fan’s suction and the car’s forward motion, creates passages for cool air to flow through, ensuring effective temperature regulation.
This type of radiator is essential for cooling internal combustion engines. Given that engines can perform up to approximately 4000 gasoline combustion cycles per minute, each generating temperatures up to around 1500°C, a heat exchanger is necessary to maintain strict control over the engine temperature.
Advantages:
Absorbs and dissipates engine heat to prevent overheating and maintain optimal temperatures.
Regulates engine temperature for consistent performance, better power output, and longer lifespan.
Equipped with pressure caps to prevent coolant boiling and ensure stable cooling.
Works with various coolants, including antifreeze, to aid in heat transfer and prevent freezing.
Made from materials that resist corrosion, extending the system’s lifespan and reducing maintenance.
Inexpensive and durable, lowering overall vehicle maintenance costs.
Disadvantages:
Requires regular coolant replacement and system checks, which can be costly and inconvenient.
Prone to leaks, potentially causing coolant loss and engine overheating.
Bulky and heavy, problematic in space-constrained or weight-sensitive applications.
Can experience electrolysis, leading to accelerated corrosion and damage.
Materials degrade over time, reducing performance and causing potential failures.
Has temperature limits; extreme conditions can impact effectiveness and durability.
Not all coolant types are suitable, and incorrect coolant use can affect performance and longevity.
The oil cooler, like the radiator, is part of the engine cooling system and is primarily used for cooling the lubricating oil or fuel in vehicles, construction machinery, ships, and other engines. Given that engine oil has thermal conductivity and circulates continuously within the engine, the oil cooler plays a crucial role in cooling components such as the crankcase, clutch, and valve assembly.
Even in water-cooled engines, only the cylinder head and cylinder wall can be cooled with water, while other parts rely on the oil cooler. The main materials for oil coolers include aluminium, copper, stainless steel, and cast metal, which are welded or assembled to create a complete heat exchanger by connecting the hot and cold side channels.
During vehicle operation, lubricating oil from various lubrication systems, driven by the oil pump, passes through the oil cooler’s hot side channel, transferring heat to the cold side. Cooling water or air then flows through the oil cooler’s cold side channel, carrying away the heat and facilitating heat exchange between the hot and cold fluids. This process ensures that the lubricating oil remains at the optimal working temperature. Importantly, the oil and the cooling medium do not come into direct contact during this process.
Both supercharged and turbocharged engines require a heat exchanger known as an intercooler, positioned between the charger and the engine’s intake manifold. When air is compressed by a turbocharger, its temperature and density increase significantly. The intercooler serves to cool this high-temperature air before it enters the engine.
Without an intercooler, the high-temperature air from the turbocharger would enter the engine directly, potentially causing engine damage or even failure due to excessive air temperatures. Therefore, the intercooler is crucial for maintaining optimal engine performance and preventing overheating. This component is generally only present in vehicles equipped with a turbocharger.
In the ever-evolving field of thermal management technology, liquid cooling plates are particularly notable. Unlike conventional heat sinks, they offer more efficient thermal management for battery not engine or coolant, making them ideal for high-performance environments like electric vehicles, advanced computing systems, and industrial machinery.
Excess heat generated by the battery is transferred through contact with the surface of an aluminium plate. The liquid cooling system uses the high heat transfer coefficient of liquid flow to efficiently transfer heat. The coolant flows through internal channels, absorbing and carrying away the heat.
Lithium battery packaging—square, cylindrical, and soft pack—affects performance, efficiency, and safety. Square batteries provide high efficiency but face heat dissipation challenges. Cylindrical batteries offer good heat dissipation and consistency but have lower energy density. Soft pack batteries are flexible and high in energy density but more costly.
Effective heat management is crucial. Advances include phase change materials with liquid cooling, optimized air designs, and hybrid cooling methods, improving performance and safety across battery types.
He trabajado en la gestión térmica de baterías durante más de 5 años, ocupándome de muchos proyectos internacionales. Si tiene curiosidad sobre los productos o servicios de refrigeración líquida de baterías, ¡no dude en hacerme cualquier pregunta!