Air Cooling vs. Liquid Cooling: How to Choose？

Air Cooling:

An air cooling system utilizes air as the cooling medium, exchanging heat through convection to lower the temperature of the battery.

Air cooling systems have the advantages of simple construction, easy maintenance, and low cost. Air cooling involves using fans or blowers to circulate air around the battery pack for heat dissipation.

In an air cooling system, the battery pack is usually equipped with a radiator that absorbs the heat from the batteries. Subsequently, fans or blowers blow the surrounding air over the radiator to dissipate the heat.

The limitations of air cooling systems are primarily seen in their limited cooling capacity, especially in high-temperature environments, where they may not provide an equally effective cooling effect compared to liquid cooling. Additionally, this type of system typically requires fans for cooling, generating noise, and occupying additional space within the device or system, making it less suitable for noise-sensitive or space-constrained scenarios.

The cooling efficiency is also lower, making it challenging to achieve uniform battery cooling and maintain a consistent temperature distribution, potentially leading to overheating or overcooling in certain areas.

Furthermore, in situations with high heat generation, such as high-performance lithium-ion batteries, relying solely on air cooling may not effectively lower the temperature, resulting in increased operating temperatures that could impact battery performance and lifespan.

However, air has lower specific heat capacity and thermal conductivity, making it less suitable for high heat generation applications. Currently, it is more commonly used in:

• Consumer electronic products such as smartphones, laptops, and tablets.

• Low-power electric cars and electric bicycles.

• Small-scale energy storage systems.

Liquid Cooling:

A liquid cooling system utilizes a liquid as the cooling medium, dissipating the heat generated by the battery through convective heat exchange. The structure of a liquid cooling system typically involves one or multiple curved water pipes embedded within the casing. During operation, the inlet and outlet of the pipes are connected to an external circulating water system. The circulating water system delivers cold water to the pipes, which then flows through them. The cold water flowing along the pipes absorbs heat from the walls, which is then emitted by the batteries. Subsequently, the cold water warms up, and the heated water returns to the circulating water system from the pipe outlet.

This is because liquid cooling systems offer several advantages:

• Improved Heat Dissipation and Reduced Noise: Liquid cooling systems typically dissipate heat more effectively, leading to better temperature control and heat management. Additionally, liquid cooling systems generally generate less noise compared to air cooling fans.

• Enhanced Cooling Capacity and Uniform Cooling Distribution: Liquid cooling can handle higher heat loads while maintaining lower operating temperatures. Liquid cooling systems provide a more uniform cooling distribution between battery units.

• Precise Temperature Control: Liquid-cooled energy storage systems directly dissipate heat from the battery cells through the coolant, allowing for precise temperature control unaffected by external conditions.

• Safety, Cost-effectiveness, and Suitable for High Capacity Energy Storage: Liquid cooling systems are not only safer and more cost-effective but also more suitable for high-capacity energy storage. Compared to traditional air-cooled containers, liquid cooling systems can increase energy density by 100%, saving over 40% of the floor space.

• Energy Efficiency: Liquid cooling systems can save approximately 30% more energy compared to air cooling systems. Simultaneously, they maintain lower cell temperatures and better temperature uniformity, effectively extending battery life, reducing economic input, and shortening the payback period.