Highly efficient battery production thanks to ideal production conditions


Electromobility is booming. That's why the BMW Group is building a new pilot plant to produce lithium-ion battery cells in Parsdorf near Munich. Following the already successful collaboration between Weiss Technik and the BMW Group regarding the supply of a drying room for a research facility in 2019, Weiss Technik has now also been awarded the contract for this important pilot project. The focus is on the safe and particularly energy-efficient air dehumidification of the production rooms. This is because producing the extremely dry process atmosphere needed can require 40-50% of the energy required for battery production.


As an established partner, Weiss Technik will plan and implement the necessary dry room and air conditioning technology for the new pilot plant, which includes a Cotes Ultradry Dehumidifier. The production of highly efficient, safe, and stable lithium-ion batteries for electric vehicles is a complex and extremely sensitive process. To be able to produce high-performance batteries in the long term, it is essential to precisely maintain the required climatic conditions in the various production steps. Deviations can negatively affect the batteries' performance and durability, so to prevent this, reliable and efficient ventilation is required that works safely, especially in the area of air dehumidification.


The project includes the construction and air-conditioning of ten individual rooms, some of which have different drying room conditions. These cover a total area of approx. 3000 square meters within the pilot plant. The individual areas are air-conditioned separately or autonomously to ensure the highest possible energy efficiency, thereby making production economical. The rooms are designed for optimal conditions. By dividing the production into separated rooms, the individual climate conditions and air humidities required for the respective process steps can be precisely regulated at every point. In addition to humidity and air conditioning, air purity also plays an important role in ensuring product quality. For maximum process reliability, the system is planned in such a way as to operate with active leakage minimisation and with the air injected via fine filters.

In addition to the air-conditioning technology and the adsorption dryers, Weiss Technik is also supplying the entire cell and steel construction, including walls and ceilings as well as airlocks, ducts, and pipelines. For cell construction, Weiss Technik works with a modular kit that has been tried and tested in many projects throughout the world and facilitates particularly tight chambers of any size. The ductwork is designed to be particularly low-leakage and to prevent moisture or foreign matter from entering the rooms - another important factor in ensuring process conditions.


  • Ultradry Adsorption Dehumidifiers with 3 rotors
  • intake + 1 main units with dew point down to -70°C
  • Heating resource: hot water


Image: Cotes Ultradry Dehumidifier being prepared for transport to BMW. The smaller unit is the intake module and the larger unit is the main module. The two modules create a highly efficient dehumidification airflow for hypersensitive battery dry room environments.

The Cotes dehumidification system used for the project works according to the principle of adsorption dehumidification and is one of the most efficient systems on the market (Read more). This is important because up to 40-50% of the energy required to manufacture a battery is needed to dry the air. The adsorption dryers with individually dimensioned drying wheels are installed directly above the drying rooms as well as in the technology annex and reliably ensure the air is prepared for the respective process steps with dew points down to -70°C as required. The air stream to be dried flows through a structure made up of layers of fibre fleece with chemically bonded silica gel and metal silicate and is dehumidified to the required dew point temperatures. In the counterflow, the moisture adsorbed in the silica gel is expelled using hot regeneration air, which allows a continuous dehumidification process to be realised.

BMW-Weiss-Cotes shipmentImage above: Cotes Ultradry Dehumidifier ready for transport to BMW.


Weiss Technik went straight into detailed planning when the contract was signed. With the help of an optimised assembly process, this will be completed on schedule by the beginning of 2022 so that production, delivery and installation of the plant can begin immediately. The commissioning of the individual rooms will take place successively and should be completed by the end of 2022, but Weiss Technik will continue to take care of the systems with regular maintenance and servicing work, including after the conclusion of the project. Weiss Technik has a unique service network that ensures high plant availability with short travel distances and fast response times. See the construction start of the dry rooms at BMW Group in Parsdorf.

Weiss Technik Logo

The Weiss Technik companies

The Weiss Technik companies include the product areas of environmental simulation, heating technology, air conditioning technology, and pharmaceutical technology ( Customers receive solutions and products that are used in research and development as well as in production and quality assurance. A strong sales and service organisation with 22 companies in 15 countries at 40 locations support the customers and ensures the operation of the systems - around the globe. The Weiss Technik companies are part of the Schunk Group based in Heuchelheim near Gießen.

Schunk Group

The Schunk Group is a global technology company. The company is a leading supplier of products made of high-tech materials – such as carbon, technical ceramics, and sintered metal – as well as machines and systems – from environmental simulation and air conditioning to ultrasonic welding and optical machines. The Schunk Group has around 9,000 employees in 29 countries and achieved sales of €1.2 billion in 2020.

Cotes Exergic Technology for battery dry rooms

Cotes offers an Ultradry-air solution for battery dry rooms that uses our Cotes Patented Exergic Technology, enabling massive energy reductions, cost savings, and huge CO₂ emissions reductions of up to 95%.

Did you know that:

  • Dehumidification for battery dry rooms counts for 43% of energy consumption in battery cell production
  • Cotes Exergic Technology can cut battery dry room dehumidification energy consumption by 30-50%. The remaining energy required for drying the battery dry room can be sourced from waste heat or heat pumps, enabling a total reduction in a range of 80-90%.
  • It is possible to reduce the cost of the energy bill for dry room dehumidification by up to 66%
  • With the right dry-air solution for your battery dry room, it is possible to cut the total CO2 footprint of battery packs by 7-9%

If you are a car or battery manufacturer that wants to go green(er) and save costs, then reach out to us.

Cotes can help you find the right dry-air solution for your facilities and give you the competitive advantage of a more sustainable Li-ion battery.

Contact Vincent von Wieding, Head of Battery Manufacturing Unit for more information at



If you are curious about what cost savings translate to in CO2 reduction then have a look at the free online calculator below.

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