Why are dry pumps better for Li-ion battery electrolyte degassing?

Lithium-ion electrolyte degassing requires robust and reliable vacuum pump without downtime losses. Dry vacuum technology is prefered by major Lithium-ion battery manufacturers owing to their performance, proven reliability and low cost of ownership.

While oil-sealed rotary pumps have been traditionally used in the Lithium-ion battery production process, dry screw vacuum technology is cost-effective and environmentally friendly.

Lithium-ion battery production consists of several steps such as the mixing of chemical slurry, the vacuum drying of electrodes, filling, degassing and sealing, which are all carried out under a vacuum environment to remove solvents as well as moisture and gas traces.

The process of electrolyte degassing is carried out in vacuum after prefilling the battery cells with electrolyte solution. This ensures the Lithium-ions can move freely, enabling efficient charging and discharging. It is essential to remove moisture, gases and contaminants to retain the purity of the electrochemistry for optimum performance and long life of the battery cells. Chemicals such as Dimethoxyethane (DME), Dioxolane, and Lithium Hexafluorophosphate could be present in the solution and the GXS materials of construction have been developed to be compatible with these type of harsh process materials.

• Electrolyte degassing requires a stable vacuum pressure less than 0.1 mbar.
• As chemicals are present in the solution, vacuum pumps need to be robust and capable of managing the process duty cycles.
• The pumps must provide continuous reliable operation to ensure the uniform removal of gases and deliver low ultimate pressures without downtime losses.

• GXS has advanced sealing technology that prevents migration of process materials from entering in to the gearbox, eliminating gear-oil contamination and ensuring long term reliability and uptime.
• The enhanced screw-type rotors, with a variable pitch tapered design, ensure uniform compression for improved thermal control, and delivers optimised pumping performance at all pressures.
• With different options catering to medium and harsh-duty applications, the pump has excellent dust, liquid and vapour-handling capabilities.

• Although oil-sealed pumps have a low capital cost compared to that of dry vacuum pumps, the oil can easily get contaminated. This results in frequent oil changes, leading to high maintenance costs and downtime losses.
• GXS dry technology has proven to be reliable and cost-effective with an optimum-yield throughput whilst efficiently managing the harsh process materials of Lithium-ion battery manufacturing.