How do you keep your battery pack cool at high power?

Discover the different cooling methods for EV battery packs

When building or converting an electric vehicle (EV), temperature control of your battery pack is crucial. A properly cooled battery pack performs better, lasts longer, and is safer. Operating outside of the optimal temperature range can lead to reduced range, lower power, and even safety risks. But how do you ensure effective cooling, especially at high power? Discover the different cooling methods for EV battery packs here.

Air cooling: Simple but limited

Air cooling is the simplest method, but often insufficient for high power applications. You are too dependent on the ambient temperature and air flow, which is not always optimal for your batteries. For demanding applications, air cooling is usually not sufficient.

Liquid Cooling: Efficient and Adaptable

Liquid cooling is more effective and offers more opportunities for optimization. A liquid-cooled system requires more components than an air-cooled system, but also offers more room for improvement.

Two main methods of liquid cooling are:

1. Cooling tubes through modules: The Power Battery modules offer the possibility to route cooling tubes through the modules. This allows coolant to flow directly through the battery modules for efficient cooling.
2. Cooling plates on terminal blocks: Mount insulated cooling plates on the main poles of the modules. It is crucial to ensure good heat conduction from the batteries to the poles. This method is less ideal because of the distance between the heat source and the cooling surface.

The temperature difference between the batteries and the coolant determines the degree of heat transfer. The greater this difference, the more effective the cooling.

Tips to improve your liquid cooling system:

1. Increase the flow rate of the coolant: This slows down the temperature rise of the coolant. Technically, this reduces the difference between the inlet and outlet temperatures. Use a higher flow pump or add more parallel cooling tubes.
2. Lower the coolant temperature: Lower fluid temperature increases heat transfer. In extreme cases, dry ice is sometimes added to the cooling system.
3. Use special coolants or additives: Water is the most commonly used coolant, but there are alternatives and additives that can improve heat transfer.
4. Spray the radiator with evaporating liquid: In racing, CO2 or pure alcohol is sometimes sprayed on the radiator to increase heat transfer via evaporation.
5. Add an air conditioner: An air conditioning system can significantly increase the temperature difference between the cooling system and the heat source.

Immersion cooling: Advanced but expensive

This method involves immersing the entire battery pack in coolant. This technology is already used in supercomputers. It is very effective but also expensive, because of the special electrically insulating and thermally conductive fluid that is needed. This fluid must:

• To be electrically insulating
• Be thermally conductive
• Have no negative impact on the materials to be cooled

Developing such a fluid is complex and expensive, making this method less accessible for most EV projects.

Choose the right cooling method for your EV project

For most EV projects, liquid cooling the best choice. It is effective, customizable and relatively affordable. The components for a liquid cooling system are widely available and therefore relatively cheap. In addition, you can easily experiment with different subsystems to improve performance.

If you need maximum power for a long time, it is important to optimize your cooling system as much as possible. Keep in mind that the temperature of the batteries in high-power applications is close to the maximum of 60-70 degrees Celsius can come. Use above 70 degrees Celsius very dangerous, so make sure the temperature stays below this level.

Would you like tailor-made advice for your EV project? Then contact our experts who specialize in cooling methods for high-power battery packs. They can help you find the ideal solution for your specific situation.

By choosing and optimizing the right cooling method, you ensure that your battery pack performs optimally, lasts longer and remains safe, even at high power. Good luck with your EV project!