Cell & Pack Manufacturing

QA/QC Technologies - Terahertz CALENDARING

To date no sensor technology was capable of measuring coating density, coating thickness and conductivity simultaneously, accurately and rapidly during the in-line coating process. Terahertz sensors offer a solution that provide density, thickness and conductivity in one measurement, allowing for real-time feedback and control.

Density of the coating

Density of the coating: The mass of active material per unit area dictates the final capacity of the electrode and while higher coat weights are desirable to increase energy density, they typically also lower the power density.

Conductivity of the coating: High conductivity improves the capacity at higher discharge rates, with more energy extracted from the battery at a given time.

Sources: Teraview

Provider examples:

FORMATION/AGING

Currently deployed at US battery manufacturer

FILLING

Electromagnetic Wavelength 1 mm to 100 μm

Thickness of the coating: Ensuring the homogeneity of coating thickness in the production process is one of the biggest challenges in high volume manufacturing. Thicker electrodes contain a greater amount of active materials, increasing energy density, but also have greater diffusion distances, lowering power output, as well as potentially causing uneven response across the electrode and leading to quicker degradation.

Conductivity of the coating

HOW IS IT DONE? - EXAMPLE METHODS

WINDING/STACKING

Thickness of the coating

WHY IS IT IMPORTANT TO CAPTURE THEM?

SLITTING/NOTCHING

WHAT ARE THE FEATURES?

EOL

Extracted from the PDF; charts and images may read imperfectly.