Cylindrical Cell Lab Line Equipment For Battery R&D

Lithium-ion batteries (LIBs) are commonly used in small electronics (smartphones, tablets, drones) and electric vehicles due to their outstanding energy storage capability. The most common three LIB forms are coin cell, pouch cell and cylindrical cell. Cylinder or cylindrical cells can be commonly seen in laptops, e-bikes, medical instrument and a lot of power tools. This design is one of the most widely used packaging styles for primary and secondary batteries with advantages of easy manufacture process and good mechanical stability.

MSE Supplies provides a full set of cylinder cell production line solutions. We can supply all the equipment and materials required in the production process. Please contact us for more details.

Cylindrical Cell Assembly Procedure

Cylindrical cells are shaped as small and round in a rigid cylindrical can, consisting of sheet-like anodes, separators, and cathodes. They are easily packed into devices with various sizes. This shape design can prevent swelling and deforming, one of most important features for cylinder cells. Common types of cylinder cells includes 14650, 17490, 18650, 21700, 26650 and so on. (The first 4 digits of the designation indicate the physical dimensions while the 5th digit indicates cylinder cell. E.g. the 18650 battery is a 18mm around by 65mm long cylinder cell.

• Electrode Sheet Preparation

The electrode of lithium-ion battery (LIB) is composed of active materials, conductive agent, battery binder and dispersant follow by the feeding sequence: active material, conductive agent and binder. feeding time, feeding ratio require strict process. The mixing process (rotation speed, vacuum, temperature, humidity, etc.) and final slurry properties (viscosity, particle size, solid content, etc.) should strictly follow the procedure according to the materials. Furthermore, the slurry needs to be filtered to remove large particles, precipitation, ferromagnetism and other substances. Here are recommended electrode formulations:

• Cathode: 96% Active material + 2% PVDF binder + 2% Carbon black
  Solvent: NMP
  The PVDF powder should be baked at 80℃ for 8 hours.
• Anode: 96% Active material + 2% CMC/SBR binder + 2% Carbon black
  Solvent: De-ionized water (Conductivity ≤1µs/cm)

The homogeneous paste is coated on a sheet of conductive metal foils (current collectors) using coating machine. Afterwards, the dried electrode sheets are placed into a rolling press to be compressed at high pressure to obtain certain porosity and thickness.

• Cylindrical Cell Assembly

The electrode sheets are sliced into strips using slitting machine and tabs are welded together with the current collectors. One tab is welded to the bottom of the inside cylinder case using spot welding machine. A cell core is inserted and fixed into the cylinder case. Afterwards, use grooving machine to groove the case and weld the other tab to the top cap of the case. An electrolyte injection system is then used to add the liquid electrolyte into the cell and seal the cap to the opening side of the case. The whole assembled process should be operated in a controlled environment to protect battery damage from air and water.

• Battery Testing

   Test the performance of assembled battery cells using battery analyzers provided by MSE Supplies.

References

• "Battery recycling technologies: Recycling waste lithium ion batteries with the impact on the environment in-view." Journal of Environment and Ecology, DOI 10 (2013): 14-28.
• "Effect of electrolysis parameters on the morphologies of copper powder obtained in a rotating cylinder electrode cell." Powder Technology 201.1 (2010): 57-63.