Electric battery systems form the heart of modern electric vehicles and industrial applications, but their performance depends heavily on a crucial factor: temperature. Effective battery cooling is essential for safe operation, optimal performance, and a long lifespan of your battery system.
Whether you are working on the electrification of construction machinery, industrial vehicles, or other applications, insight into thermal battery management helps you make the right choices for your specific situation.
Why do electric batteries need cooling?
Electric batteries require cooling because they generate heat during use, which negatively affects their performance, safety, and lifespan. Without adequate heat dissipation, temperatures can rise to dangerous levels and cause permanent damage.
Lithium-ion batteries perform optimally within a specific temperature range, usually between 15 and 35 °C. When the temperature becomes too high, various problems occur. Internal resistance increases, causing the battery to become less efficient and produce more heat—a negative spiral. At extreme temperatures, thermal runaway can occur, where the battery becomes uncontrollably hot and can even ignite.
In addition, high temperatures significantly accelerate the aging of battery cells. Every 10°C increase in temperature can halve the lifespan of a lithium-ion battery. For commercial applications, this means that an investment in proper battery cooling quickly pays for itself through a longer lifespan and better performance.
How is heat generated in battery systems?
Heat in battery systems is generated primarily by internal resistance during the charging and discharging of the cells. This resistance converts a portion of the electrical energy into heat, the amount of which depends on the current and the condition of the battery.
Heat production follows Joule's law: heat = current² × resistance × time. This means that higher currents produce exponentially more heat. During fast charging or high power output, heat production can quickly rise to problematic levels.
Other heat sources are chemical reactions within the cells, especially in older or damaged batteries, and external heat sources such as ambient temperature or nearby components. In industrial applications such as heavy equipment ambient temperatures of 50 °C or higher can further complicate the situation.
What are the different types of battery cooling?
The main types of battery cooling are passive cooling, air cooling, and liquid cooling, each with specific advantages and disadvantages depending on the application. Passive cooling uses only heat dissipation through materials, while active systems use forced air or liquid circulation.
Passive cooling works via heat conduction and natural convection. This is the simplest form, where heat is dissipated through the coil housing and cooling fins. This method is inexpensive and reliable, but limited in cooling capacity.
Active air cooling uses fans to blow air past the battery cells. This system is relatively simple and cost-effective, but less effective under high heat loads. Liquid cooling, on the other hand, uses a liquid (usually a glycol-water mixture) that can transport heat much more effectively than air.
What is the difference between air and liquid cooling?
The main difference between air and liquid cooling lies in cooling capacity and complexity. Liquid cooling can dissipate 3 to 4 times more heat than air cooling, but requires more components, such as pumps, hoses, and heat exchangers.
Air cooling is easier to implement and maintain. The system consists of fans and air ducts, has no risk of leakage, and is lighter. However, the cooling capacity is limited, especially in warm environments or at high power densities.
Liquid cooling offers superior cooling performance and greater design flexibility. The liquid can transport heat to an external radiator, allowing the battery to remain compact. However, this system is more complex, more expensive, and carries a risk of leakage. For high-performance applications, liquid cooling is often unavoidable.
How does thermal management work in practice?
Thermal battery management works by combining temperature sensors, control systems, and cooling components into an integrated system that automatically keeps the battery temperature within optimal limits. The system continuously measures the temperature and adjusts the cooling accordingly.
In practice, the system starts with temperature measurements at multiple points in the battery pack. This data goes to an electronic control unit that determines how much cooling is needed. With air cooling, fans are switched faster or slower; with liquid cooling, the pump speed is adjusted.
Advanced systems use predictive algorithms that take into account the expected load, ambient temperature, and battery condition. This allows the system to proactively initiate cooling before the temperature becomes too high. In extreme situations, the system can also limit battery performance to prevent overheating.
What temperature is optimal for battery performance?
The optimal temperature for battery performance is between 20 and 25 °C for most lithium-ion batteries. Within this range, batteries achieve their highest capacity, lowest internal resistance, and longest lifespan.
Below 15 °C, capacity and power decrease noticeably due to slower chemical reactions. At temperatures below 0 °C, lithium plating can occur during charging, causing permanent damage. Above 35 °C, battery aging accelerates exponentially, while temperatures above 60 °C become dangerous.
Optimal temperature ranges may vary slightly for different applications. Racing applications often tolerate higher temperatures for maximum power, while stationary systems employ more conservative limits for maximum lifespan. The cooling system must therefore be tailored to the specific requirements of your application.
A well-designed cooling system forms the basis for reliable electrical systems. We help companies develop custom-made battery systems with optimal thermal management for their specific applications. For advice on your project, please feel free to contact us. contact Contact us.
