Lithium is a highly reactive metal that reacts with water vapor to form lithium hydroxide, hydrogen, and heat, which can lead to explosions if temperatures are too high. Not only the humid environment will trigger the above problems of lithium batteries, even the relative humidity of the normal atmosphere will also lead to quality problems in the manufacturing process of lithium batteries. When producing lithium-ion batteries, the materials used to make the cathode, anode and electrolyte do not explode when exposed to water, but they are sensitive to moisture, so the dew point in a lithium-ion dry room is usually lower than that in a dry room for lithium-metal batteries. The back-end manufacturing process for most lithium batteries requires a dry room with an indoor air dew point of -30oC dp to -55oC dp or lower.