The cooling performance of a power battery plays a pivotal role in the efficiency, service life, and safety of the battery. This critical impact stems from the heat generated during the charging and discharging processes. As temperatures rise, many effects alter key battery traits. These include internal resistance, voltage, State of Charge (SOC), capacity, and efficiency. To manage this, engineers deploy both active and passive Battery Thermal Management Systems (BTMS). These systems are vital. They keep lithium-ion batteries at the best temperatures. These temperatures are crucial for electric vehicle performance.
New energy vehicle batteries are rapidly advancing. They are moving towards higher energy density and extended range. This has increased the demand for advanced temperature management. Modern approaches, such as the use of advanced liquid cooling plates, are being refined to meet these technical demands. These enhancements will improve temperature control. They also add much to the value and function of each vehicle. As the market for new energy vehicles expands, the need for efficient thermal management systems grows. This development is poised to drive substantial scale effects in production and bolster potential growth within the battery supply chain.
This comprehensive approach to managing battery heat is a technical need and a market driver. It shows how important advanced cooling is in today’s fast-changing car industry.
Table of Contents
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Battery pack cooling methods
There are three main cooling methods for electric vehicle battery packs: air cooling, liquid cooling and direct refrigerant cooling.
Air cooling
At present, the mainstream cooling is still air cooling, air cooling using air as a heat transfer medium.
There are two common types of air cooling: 1. passive air cooling, which directly uses external air for heat transfer; 2. active air cooling, which can pre-heat or cool the external air before entering the battery system. This type of cooling is easier to achieve and less costly, but the cooling effect is poor. Mainstream miniature electric vehicles such as the Hongguang MINI EV, as well as early hot-selling electric vehicles, all use this method of battery cooling.
Literature References:ACTIVE VS PASSIVE THERMAL MANAGEMENT
Liquid cooling
Liquid cooling stands out for its superior cooling capabilities. Compared to air cooling, coolant systems have much higher specific heat capacity and heat transfer. They often exceed air-cooled systems by tens of times. This better thermal performance leads to much lower operating temperatures. It reduces temperature differences within battery packs. As a result, liquid cooling solutions contribute to notable improvements in battery efficiency, stability, and overall durability.
However, it’s important to acknowledge that liquid cooling comes with its own set of challenges. Ensuring the battery pack is hermetic is vital when adding liquid cooling. Leaks could harm the system’s integrity and performance. Also, the upfront and operating costs of liquid cooling are higher. They are higher than the costs of simpler air cooling. Despite this, the benefits of liquid cooling for thermal management and battery performance often make the investment worth it. This is especially true for applications with strict cooling needs.
Refrigerant direct cooling
Direct cooling uses a refrigerant as the heat transfer medium, which absorbs a large amount of heat during the gas-liquid phase change process, increasing the heat transfer efficiency by more than three times compared to refrigerated liquids and removing the heat from the battery system more quickly. However, this system is a dual evaporator system, there is no battery heating, no condensate protection, the refrigerant temperature is not easily controlled and the refrigerant system life is poor.
If you are choosing a cooling solution for your power cell, Trumonytechs recommends liquid cooling as your preferred solution. Although air cooling is currently the mainstream cooling method, the trend of battery development will be towards higher energy density, and the safety of high energy density batteries requires particular attention, as the negative effects of thermal runaway will become increasingly significant.
Liquid-cooled solutions have unique advantages in terms of heat transfer capability, heat transfer consistency, PACK sealing and NVH.
The second reason is that liquid cooling has been used in traditional vehicles for a long time and has a well established supply chain, and the cost of the battery system can be effectively controlled when the design and process are stable.
Technology Comparison: Advantages, Disadvantages, and Scenarios of Battery Cooling Technologies
When selecting the battery cooling technology that is best suited for a particular application, it is critical to understand how each technology performs in different environments and conditions. Below is a comparison of the three main cooling technologies: air cooling, liquid cooling and direct refrigerant cooling:
| Cooling Technology | Advantages | Disadvantages | Suitable Applications |
|---|---|---|---|
| Air Cooling | – Low cost | – Lower cooling efficiency | – Cost-sensitive applications |
| – Simple system, easy to install and maintain | – Inadequate cooling in high temperature or high load | (e.g., small electric devices, some electric vehicles) | |
| Liquid Cooling | – Efficient heat transfer | – Higher initial and maintenance costs | – Applications requiring extensive heat management |
| – Precise temperature control | – Complexity and high demands on hermeticity | (e.g., high-performance electric vehicles, energy storage systems) | |
| Direct Refrigerant Cooling | – Highest cooling efficiency | – Higher technical complexity and costs | – High temperature and high load environments |
| – Suitable for extreme temperature conditions | – Environmental impact and risk of refrigerant leakage | (e.g., server cooling, high-performance electric vehicles) |
Liquid cooling solution case
Most mainstream new energy vehicles currently use liquid cooling solutions for thermal management. The following will take Tesla as an example and give a brief insight into how Tesla carries out heat pipe cooling of its battery packs.
Tesla uses liquid cooling solution for battery thermal management, each Tesla is equipped with a special liquid cycle temperature management system, and around each single battery. The coolant used is a mixture of 50% water and 50% glycol and is green in colour.
The coolant flows through pipes and is eventually dissipated in a heat exchanger at the head of the vehicle to maintain a balanced battery temperature, thus preventing localised high temperatures from affecting the battery’s performance. Tesla’s battery thermal management system can control the temperature of the battery pack to ±2°C, effectively controlling the temperature of the battery plates.
The Module water cooling system, for example, is constructed in parallel to ensure that the coolant flowing into each Module is of a similar temperature.
How to reduce complexity and production costs
Liquid cooling solutions are becoming increasingly popular in high-performance computing, gaming, and other industries where there is a need for efficient heat dissipation. The development of liquid cooling solutions involves designing and engineering a system that can efficiently transfer heat from the source to the coolant and dissipate it outside of the system. However, there are some challenges and difficulties associated with developing liquid cooling solutions, which are discussed below:
System complexity: Liquid cooling systems are more complex than traditional air cooling systems, and require additional components such as pumps, radiators, tubing, and coolant. These additional components add complexity to the system, making it more difficult to design and manufacture.
Risk of leaks: Liquid cooling systems are susceptible to leaks, which can cause damage to the components and create safety hazards. Manufacturers must ensure that their designs are leak-proof, and develop protocols to detect and address leaks if they do occur.
Maintenance requirements: Liquid cooling systems require regular maintenance to ensure that they function properly. This includes replacing coolant, cleaning radiators, and checking for leaks. Maintenance can be time-consuming and expensive, and may require specialized tools and knowledge.
Compatibility issues: Not all components are compatible with liquid cooling systems. For example, some motherboards may not have the necessary fittings or mounting points for liquid cooling blocks, or may require additional adapters or brackets. Manufacturers must ensure that their designs are compatible with a wide range of components to ensure that their systems are widely adopted.
Cost: Liquid cooling systems can be expensive to develop and manufacture, due to the additional components and complexity involved. This can make them less accessible to consumers and limit their adoption in the market.
With new energy vehicles driven by a combination of performance and cost requirements, there is a need for power battery liquid cooling plates with light weight, good thermal conductivity, strong anti-corrosion and other fatigue resistance, and excellent process performance. At the same time, under the trend of technology such as fast charging and high range, the battery unit heat generation has increased, which also puts forward higher requirements for battery cooling capacity.
User Maintenance Guide: Battery Cooling System
Maintaining and servicing the battery cooling system is critical to ensuring battery stability and performance. Below is a compilation of measures that can be taken by Trumonytechs to maintain and optimize the battery cooling system:
Periodic Inspection
Periodically check the appearance of the cooling system, including pipes, connections, and coolant levels.
Check the cooling system for any signs of leaks, including pipes and coolers.
Clean the cooling system’s coolers regularly to ensure good heat transfer efficiency.
Troubleshooting
If you notice any leaks or abnormal temperatures in the cooling system, stop using it immediately and seek a professional technician for troubleshooting and repair.
Watch out for any unusual temperature fluctuations or alarm signals, which may be a sign of cooling system failure.
Best Practice
Avoid overusing the battery in extreme temperature conditions, which may place an additional load on the cooling system.
Change the coolant regularly, following the manufacturer’s recommendations.
Follow the manufacturer’s recommendations and guidelines to ensure proper use and maintenance of the battery cooling system.
Conclusion
Battery cooling systems are critical. They ensure battery performance, safety, and longevity. It may be air cooling, liquid cooling, or direct refrigerant cooling. Each has its benefits and uses. Good maintenance and optimization can also boost your cooling system’s efficiency and reliability.
If you need a good battery cooling solution, Trumonytechs has the tech and experience to customize it for you. We understand the unique needs of each application and can provide cooling technology that fits your specific needs. Contact Trumonytechs today for your battery cooling system solution!
FAQ
Battery cooling systems regulate the temperature of the battery by using air, liquid or refrigerant as a medium. These systems transfer heat. They help the battery stay at the right temperature. This improves efficiency and extends battery life.
Batteries generate heat during the charging and discharging process. If the temperature gets too high, it may affect the performance, safety, and life of the battery. Cooling systems keep batteries safe. They keep them from getting too hot and from having thermal runaway.
Air cooling systems use air as the cooling medium, which is less expensive and easier to maintain, but less efficient. Liquid cooling systems use a liquid (e.g., water and glycol) to cool. This liquid has higher heat transfer efficiency and suits high energy density batteries. But, it costs more and needs more maintenance.
A direct refrigerant cooling system absorbs heat through a phase change. The change is of the refrigerant from gas to liquid. This method provides very high cooling efficiency. It is ideal for high-performance applications. They need to remove a lot of heat fast. These include high-powered electronics and some electric vehicles.
You need to maintain your battery cooling system. This includes checking the coolant level and piping. You also need to clean the cooler to prevent clogging. And, check the system for leaks. Following the manufacturer’s maintenance guidelines is key to keeping your system efficient.
