Binder migration across film consolidation and pore emptying in electrode drying: a continuous model validated against drying-rate, thickness, and schedule experiments
Drying battery electrodes faster saves energy but drives dissolved binder toward the film surface, depleting the current-collector interface and weakening adhesion. Models of this migration stop convecting the binder when film consolidation ends, and models of the subsequent pore emptying omit the binder or start from an assumed binder field, so no simulation has followed binder convection through both stages that a drying schedule acts on. This study presents a continuous simulation of the dissolved binder field across both stages, driven by the published drying rates and completed by effective descriptions of the two questions the base transport physics leaves open: where the liquid of the consolidating film carries the binder, and when the binder stops moving as the pores empty. With a single parameter set, the simulation reproduces three types of published measurements: the change of the surface-to-interface binder ratio with drying rate over a factor of 5.6 and the surface and interface binder levels of films six times thicker; concentration profiles through the film interior; and the response of the interface binder to the time at which the drying rate is switched mid-process. Applied without further adjustment to a published three-stage schedule, the model reproduces the shortened drying and the full interface recovery when the rate is lowered early, and shows that its final high-rate stage begins after the binder has stopped. Combined with a coater-scale process model, the model can be used to identify operating points for electrode production that improve energy efficiency and product quality together.