Lithium-Ion Batteries Vacuum plays an essential role in lithium-ion batteries cell production.

Vacuum expertise for every step of Lithium-Ion Battery production

Leybold offers the perfect products for each vacuum step of the Lithium-ion cell production process. With the growing importance and emergence of new solutions for energy storage and mobility, Lithium-ion batteries have become more relevant. Thanks to the increasing demand, research in Lithium-ion batteries has been intense, leading to significant technology improvements regarding the batteries' capacity, power, and lifetime.

Lithium-ion batteries are one important step on our way towards the green use of energy. They are being used as energy storage solutions for renewable energy e.g., produced by wind turbines or solar panels. For our way towards sustainable mobility, Lithium-ion batteries are built-in cars, trucks, buses, or scooters for private or public e-mobility.

Starting with the fabrication of the anode and cathode material, requiring active material, solvents, binders and additives, and the copper and aluminum foils, the production process of a Li-ion battery cell consists of various steps. Each step has its specific requirements and particularities, which define the quality of the final product, the Li-ion battery at the end of the process.

Vacuum plays an essential role in Lithium-ion battery cell production. Looking at the different production steps of a Lithium-ion battery, vacuum is needed:

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Vacuum solutions in the cell production

In the different steps of the battery production process, vacuum is relevant and essential for a high battery quality. Depending on the vacuum requirements and process challenges, different vacuum pumps are suitable.

Mixing

With the help of a rotating tool many different raw materials are mixed in a form which is called slurry. This process ideally takes place under vacuum to degas the slurry, achieve homogeneity, right viscosity and purity of the slurry. Leybold TRIVAC, SOGEVAC, VARODRY and CLAWVAC vacuum pumps are most suitable even if you need large capacities.

Stacking

During the stacking process the sheets are stacked in a repeated cycle of anode – separator - cathode. The exact positioning of the sheets has a high impact on the end-product quality and can be ensured by vacuum grippers. The Leybold central vacuum solution, VACUBE, is an industry favorite, owing to its process stability and efficiency.

Vacuum Drying

After the electrodes are rolled and slit into smaller electrode bands, these coils need to be dried. For a high-quality battery, it is essential to remove most of the humidity and solvent residues. Vacuum drying is the production proven state of the art solution with drying times in between 12 and 30 hours per batch.

Leybold robust and reliable vacuum systems withstand humidity and solvent traces. Furthermore, purity in process is a must, so dry compressing pumps such as VARODRY, LEYVAC, DRYVAC and RUVAC avoid back streaming of oil particles towards the coils in a batch dryer or an in-line dryer.

Specialized vacuum solutions have been developed such as the Leybold DV4000, the DRYVAC DV650-LIB and the VARODRY-LIB for effective and reliable pumping of NMP.

Electrolyte Filling

The Electrolyte filling for the three commonly used battery cell types, Pouch, Cylindrical and Prismatic, is done under vacuum to ensure an even dispersion of the electrolyte within the cell with a perfect wetting of all components. Evacuation and partly filling are repeated several times with a typically lowest pressure of around 0.01 mbar.

The vacuum pump must withstand electrolyte (e.g. LiPF6) traces which might be dragged into the pump. As the electrolyte is classified as a hazardous substance and might build acids if reacting with water the use of Leybold dry compressing oil-free pumps such as DRYVAC are a perfect fit. Special pump designs and customized pump systems had been developed for this demanding application.

Leak Testing

For quality and safety reasons, the absolute leak tightness of the final battery cell is essential. That’s why in the final step, a helium leak test is performed to ensure a tight battery, leading to a long lifetime and high product quality. For this production step, Leybold offers different versions of helium leak detectors such as PHOENIX and PHOENIX modules or single pumps such as SCROLLVAC, VARODRY and TRIVAC for customized leak detection systems