Continuous Twin-Screw Extrusion and Rheological Analysis of Electrode Components for Optimizing Lithium-Ion Battery Manufacturing

Lithium-ion batteries (LIBs) are crucial for portable electronics, electric vehicles, and grid storage due to their high energy density and long cycle life. The manufacturing of LIBs involves several steps, including the preparation and coating of anode and cathode slurries. Proper mixing and homogeneous coating are essential for achieving high-capacity batteries with extended cycle life.
During manufacturing, battery slurries encounter a wide range of shear conditions. Rheological analysis using rotational and oscillatory rheometry is vital to:
• Verify proper mixing and homogeneous distribution of active components within electrode slurries.
• Predict storage behavior and stability.
• Understand behavior during the coating process.
Additionally, rheological techniques can evaluate the flow behavior of raw materials in powder form. Understanding the flow properties of powders ensures their correct dosing in continuous manufacturing processes using gravimetric feeders.
Furthermore, powder rheological analysis can also predict the behavior of dry-processed electrode materials during calendaring. Dry-processing is a manufacturing technique gaining more and more popularity due to its lower production costs from the absence of energy-intensive drying steps.

This study introduces continuous twin-screw compounding as a compact, energy-saving alternative to planetary batch mixers for manufacturing electrode materials. It highlights the benefits of comprehensive rheological testing of electrode formulations and raw materials in both liquid and powder forms using modular rotational rheometers. We present results from various rheological testing methods and discuss their practical relevance to the production process.