Increasing humidity levels pose a challenge to dehumidification systems maintaining low dew points in a lithium-ion battery gigafactory clean and dry room.

The electric vehicle market is expanding annually, with lithium-ion battery gigafactories emerging worldwide to keep up with the increasing demand. Among the many challenges faced by the industry due to its highly controlled manufacturing process, one in particular becomes a greater issue as new record temperatures are recorded every year in the summer months. Rising humidity levels in the summer pose a major obstacle to lithium-ion battery production due to the stringent environmental controls that are essential for their manufacturing. Even minor fluctuations in dew point are enough to alter the cells and lead to product quality issues and downtime, decreasing the efficiency of a gigafactory and resulting in manufacturing targets not being met.

Lithium-ion battery manufacturing requires specialist production areas called clean and dry rooms that require industrial dehumidification systems to maintain the air within the controlled space at low dew points (dp). A typical indoor environment of 24.5°C and 60% RH (relative humidity) translates to approximately 16.5°C dp; in comparison, dry rooms for lithium batteries need a <1% RH and a dew point ranging from -35°C to -45°C. Battery chemistry of the next generation of lithium batteries may have even tighter requirements, requiring dew points of -60.0°C and even below -80.0°C for critical areas like electrolyte fill. An ultra-low humidity room lowers the risk of electronic failures through moisture damage, protects materials from corrosion or damage caused by sensitivity to high relative humidity, reduces bacterial growth, and prevents the degradation of hygroscopic materials. Effective dehumidification is a necessary fire prevention measure, as the interaction between water vapour and lithium results in an exothermic reaction that could ignite the hydrogen-air mix and lead to explosions and toxic smoke emissions. 

A combination of construction techniques and specialised equipment ensures that gigafactory dry rooms can consistently maintain the extremely low dew points necessary to protect sensitive processes and materials. Since the required dew point is below zero degrees, the required dryness level in clean and dry rooms cannot be achieved during the drying process in the refrigeration cycle, but only using a desiccant. This can be done using a HVAC system that consists of a make-up air handling unit (AHU) supplying fresh air and a dehumidifier unit (DHU) to perform a continuous drying process that contains a desiccant wheel, heaters, filters, and fans. An envelope system is also an integral part of a dehumidification system. A fully sealed panel system with multistage airlocks equipped with well-sealed doors will insulate the dry room and protect it from moisture ingress. Internal detailing also aids in achieving low infiltration rates by creating multiple sealing points, such as a vapour-proof barrier underneath flooring, which can improve air leakage rates, as can floor and ceiling coving sealed with clean room sealant.

As global temperatures rise due to climate change and lithium-ion battery manufacturing requires increasingly lower dew points, the need for efficient and effective clean and dry room solutions is imperative to continue meeting manufacturing targets. Innovations in specialized construction techniques and advanced dehumidification systems employing desiccant technology are essential for the future of gigafactories. For the opportunity to have in-depth discussions about this and other challenges facing gigafactories, as well as the chance to hear from top industry experts, join us at the 2nd Battery Gigafactory Summit USA: Advances in Planning, Engineering and Operations taking place in Nashville, Tennessee, on November 13–14, 2024. 

For more information, visit our website or email us at info@innovatrix.eu for the event agenda.