The Need for Dehumidification for Lithium-ion Battery Manufacturing

Lithium-ion batteries are at the core of driving the performance of electric vehicles and make up the lion’s share of an electric vehicle’s cost. In this article, Deepak Pahwa, Chairman of Pahwa Group and Managing Director of Bry-Air, explains the need to deploy dehumidification solutions for cell manufacturing and battery assembly operations.

The need for dehumidification for Lithium-ion battery production

Lithium-ion batteries are affected by uncontrolled temperature and humidity. If a lithium-ion battery is exposed to moisture during production, it may lead to impaired quality, resulting in reduced product life, charging capacity and safety concerns.

To achieve stringent environmental conditions, installing a dry room helps in the production of quality batteries. Ideally, the dry rooms need to maintain the RH at less than 0.5 % during lithium-ion cell manufacturing and 10% for the battery assembly process with the help of an environment-controlled dehumidification system. At the same time, the moisture control equipment in dry rooms aids in achieving extremely low dew points, reaching up to -80°C, which is ideal for processing hygroscopic and moisture-sensitive materials. Lithium-ion battery manufacturing requires very strict environmental conditions accompanied by constant real-time monitoring. The various materials in a battery are highly hygroscopic (tending to absorb moisture from the air) in nature, which necessitates continuous regulation of humidity level within a narrow range throughout the manufacturing and assembling of the battery. Maintaining the humidity at less than 0.5% in a stable environment is ideal for Lithium-ion battery manufacturing.

To achieve stringent environmental conditions, installing a dry room helps in the production of quality batteries. Ideally, the dry rooms need to maintain the RH at less than 0.5 % during lithium-ion cell manufacturing and 10% for the battery assembly process with the help of an environment-controlled dehumidification system. At the same time, the moisture control equipment in dry rooms aids in achieving extremely low dew points, reaching up to -80°C, which is ideal for processing hygroscopic and moisture-sensitive materials.

General Recommendations

• Moisture level in Lithium-ion battery processing areas should have less than (-) 35°C (-31°F) dew-point and/or moisture content of 0.14 grams per kg of dry air.
• Room temperature should be maintained at recommended levels, around 25°C (77°F), with a tolerance of +/(-) 2°C (36°F).
• The air change rate in the production room should be 20 to 50 air changes per hour with the maintenance of minimum fresh air introduction for positive room pressure and ventilation for workers.

Lithium, as a material, is highly hygroscopic in nature. This poses a major challenge as the affinity of lithium to attract moisture can lead to faulty Li-ion battery manufacturing, which, in extreme cases, can give rise to serious safety issues. This requires the Li-ion batteries to be manufactured in a strict moisture-controlled environment with less than 0.5% RH. Considering desiccant dehumidification’s critical role in manufacturing Lithium-ion batteries, installing efficient low dew point dehumidifiers becomes imperative to producing quality batteries.