Development of a volumetric radiation model for CFD simulation of NCM cathode calcination in packed beds

초록

Nickel-cobalt-manganese (NCM) cathode materials are essential components of high-performance lithium-ion batteries (LIB), and calcination is a critical step that directly determines the crystallinity, particle morphology, and electrochemical properties of the final product. At 700-900 degrees C, radiative heat transfer becomes dominant while gas species are generated during thermal decomposition and dehydration. However, conventional computational fluid dynamics (CFD) approaches cannot simultaneously model gas generation within a cathode powder bed and radiative heat transfer from heaters, as standard radiation models require wall boundaries while gas transport requires fluid domains. Here, we develop a volumetric radiation model that enables direct application of radiative heat sources within fluid domains through a gray-medium approach employing user-defined functions. The model, validated through thermal profiling experiments in a laboratory-scale electric furnace operating at 850 degrees C for 20 h, revealed vertical temperature stratification of 60-80 degrees C during the heating phase. Parametric studies identified optimal parameters of absorption coefficient of 1/10 mm and correction factor of 0.4, achieving predictions within +20 degrees C of experimental data. The validated CFD model provides a computational framework for analyzing and optimizing thermal behavior in NCM cathode calcination furnaces.

키워드