With every type of drive, the optimal functioning of the cooling and air conditioning system is crucial for the comfort of the driver and passengers as well as for the efficiency and service life of the drive system. However, thermal management plays an even more important role in electric vehicles compared with the combustion engine. We’ll therefore explain how the different thermal management systems are designed.

Of course, you’re already familiar with the thermal management of vehicles with combustion engines. From a technical perspective, the thermal management of an electric drive has a similar design. However, it is more complex because it involves more components and sometimes also several cooling and refrigerant circuits to ensure the correct temperature control of the cabin, battery, motor, and power electronics. The increase in electrification thus means that the air conditioning service is becoming more important for you and your customers, leading to higher service volumes.

Regular maintenance of the air conditioning system by your workshop is a value-preserving measure and contributes to the vehicle’s operational reliability. If the air conditioning system fails, this can lead to a reduced cruising range, vehicle stoppage, or even damaged components. Thermal management is a real opportunity for the future.

Full support

At MAHLE, we’re strengthening this important future segment relating to temperature control and continuously developing our product portfolio. MAHLE has an impressive thermal management range: approximately 4,700 PREMIUM LINE products provide OE quality for customers who want to have the best possible product in their vehicle. In addition, we offer around 3,500 high-quality products in OE-matching quality at an attractive price. With roughly 2,400 product pairs, your customer is free to choose. Around 1,350 products in MAHLE’s thermal management portfolio are included in the SIMPLE FIT range. SIMPLE FIT makes things easier for you, as you don’t need to order certain accessories such as O-rings, seals, or screws separately for items with this labeling. They’re already supplied and/or preassembled.

Every type of drive depends on high-performance filtration, which is why MAHLE also develops pioneering solutions in this area. Our product portfolio includes 200 cabin filters for electric vehicles, 80 oil and fuel filters for hybrid vehicles, and 70 air filters for vehicles with a fuel cell or hybrid drive.

In the workshop equipment segment, the ArcticPRO© model series comprises entry-level, professional, and premium models for refrigerants R134a and R1234yf. With the help of E³ technology, you can carry out the service in an eco-friendly, economical, and efficient manner.

MAHLE also provides you with plenty of support, such as an efficient Europe-wide service network, technical documentation, marketing support, installation videos, technical training, and much more.

Thermal management training from MAHLE:

In Germany, mechatronics specialists working on high-voltage systems require a two-day training course to become “experts for work on high-voltage (HV) intrinsically safe vehicles.” This training course teaches employees to assess the risks when working on the system and how to switch off all the current to the system for the duration of the work. The repair or replacement of live high-voltage components (batteries) requires special qualification.

MAHLE Aftermarket also offers special training on engine cooling and air conditioning for passenger cars, trucks, and agricultural and construction machinery:

  • T-AC Air conditioning in the vehicle: air conditioning system design, function, and common causes of failure
  • T-TH Thermal management: cooling systems and components of the modern combustion engine
  • C-SK Expertise in vehicle air conditioning
  • C-CG Compressor Guarantee Plus: Certification of participation in the Compressor Guarantee Plus program

Everything at a glance

View our full training program HERE.

To arrange a date, register, or if you have any questions, you can contact your MAHLE Aftermarket trading partner or send an e-mail to ma.training@mahle.com.

Direct and indirect temperature management

The focus of e-mobility is on the vehicle’s range. And this is significantly influenced by the efficiency of the individual components of an electric drive. Therefore, the electric motor, power electronics, and battery must be kept within the most efficient temperature range. This is between approximately 15°C and 30°C. Battery life decreases at operating temperatures of 40°C or higher, while efficiency drops and performance is weaker at temperatures below 0°C. Furthermore, the temperature difference between the individual battery cells must not exceed a particular value. This is only possible with a sophisticated thermal management system. Basically, a distinction can be made between direct and indirect systems.

Read more about the differences between these two systems in our Thermal management in electric and hybrid vehicles brochure. It also contains valuable background information and helpful workshop tips.

Evolution of the circuits

The thermal management systems in combustion engines and electric drives have similar technical structures. In the latter, the air conditioning system often has a direct or indirect influence on the cooling of the batteries and electronics. But because electric drives emit little waste heat during operation and none at all when stationary due to their high efficiency, auxiliary heaters are necessary to warm up the cabin.


Combustion engine

In conventional combustion engines, the cooling system transports the heat generated in the engine to the outside. The air conditioning and coolant circuits are separate. In summer, the engine cooling system protects against overheating, while the air conditioning system cools the cabin.


Turbocharged internal combustion engine

In vehicles with turbochargers, charge air coolers are necessary to cool the compressed and thus heated intake air. Older designs are often direct charge air coolers, meaning that they cool the charge air directly via the ambient air.

In more modern systems, indirect charge air cooling is often used. In this process, the heat is dissipated through coolant from the charge air cooler and directed into a separate low-temperature radiator. The heated coolant is then cooled by the ambient air before it flows back to the charge air cooler. Since this circuit has a significantly lower temperature than the engine cooling circuit, which has a temperature of approximately 90°C, these circuits are always separated from each other.


Plug-in hybrid

Lithium-ion batteries require precise temperature control. The air conditioning circuit is therefore becoming an important element of heat management in plug-in hybrids. The use of two separate powertrains leads to several coupled circuits at different temperature levels. To maximize the battery’s service life, it must ideally be kept below 40°C. This requires intelligent thermal management.


Fully electric drive

In battery electric vehicles, the battery and power electronics take center stage, because optimal temperature control for the battery is directly linked to the cruising range and service life. The fast charging process generates up to 12 kW of heat, which has to be absorbed by the cooling system. Alongside battery cooling, the operation of the interior air conditioning in particular must be as energy efficient as possible. This is achieved through optimized air conditioning.


Fuel cell

In vehicles with a fuel cell drive, there’s an additional challenge. The amount of heat to be dissipated from this type of vehicle is comparable to that of a vehicle with a combustion engine. However, the difference between the temperature of the cell and the outside temperature is smaller. This drastically increases the demands placed on the cooling system. The requirements for the thermal management of the battery remain unchanged compared with an electric vehicle.

Air conditioning and cooling: MAHLE gives you the edge!

Available exclusively from MAHLE: a complete range of parts, workshop equipment, diagnostics, and services for engine cooling and air conditioning. MAHLE is THE strong partner for you when it comes to air conditioning and cooling—find out why >> HERE.


We regularly provide technical tips relating to the powertrain, thermal management, and mechatronics in automobiles.