Meaning
Dimensionless distribution measurements describe the width of a powder’s particle size distribution to evaluate material uniformity. The volumetric span calculation compares the difference between the d90 and d10 values to the median d50 diameter. Low span values indicate a narrow distribution, which is necessary to ensure consistent drying and calendaring behavior in electrode sheets.
Battery manufacturers use this metric to grade powder consistency across different supply lots.
Width Measurement
High span values indicate a wide distribution with a large variation in particle sizes. This wide distribution can cause uneven coating thickness on the electrode line.
Coating Uniformity
Narrow distributions pack more evenly during calendaring, which prevents localized high density spots. These spots can cause mechanical stress and accelerate electrode degradation.
Slurry Behavior
A well controlled span ensures that the slurry maintains a stable viscosity during the coating process. This stability reduces the frequency of line adjustments.
