What is a battery dry room, and why does the air inside need extremely low dewpoints?

A battery dry room is a type of room where the moisture content of the air is controlled to ensure quality and yield products to be manufactured. This is especially important to safely manufacture lithium-ion batteries.

A battery dry room represents an environment surrounding several steps in the manufacturing process of Li-ion batteries where the energy demand is often very high because of the large volume of air that needs to be temperature-controlled and dried. A battery dry room is an essential part of the manufacturing plant for Li-ion batteries to ensure safety, quality and nominal conditions for battery manufacturing. 

Manufacturing Li-ion batteries for electric vehicles is a complex and extremely sensitive process, as lithium is extremely sensitive to moisture in the air, easily absorbing it. This means that the slightest exposure to moisture leads to reduced performance and the product life of Li-ion batteries. A low dewpoint means less humidity in the air. Therefore, reliable and efficient dehumidification solutions to prevent lithium from absorbing moisture from the air are crucial.

To achieve a highly efficient operation of a dry room, it is crucial to ensure that both the dry room, the air handling unit and all connecting equipment are constructed for the purpose. The dry room has to be extremely tight, and air extraction should be limited as much as possible. By that, the fresh air required to hold a positive pressure in the room will be limited, ensuring that highly valuable dry air is kept within the system instead of being wasted. Similarly, welded ductwork is preferred to avoid any leakage of air. Filters and flowrates to ensure clean room demands further have to be selected carefully in order to prevent unnecessary consumers in the system.