Effect of Radial Stress on the Nanoparticle-Based Electrolyte Layer in a Center-Wound Roll with Roll-to-Roll Systems

Abstract

Recently, slot-die coating based on the roll-to-roll process has been actively used to fabricate nanoparticle-based electrolyte layers because it is advantageous for high-speed processes and mass production of uniformly thick electrolyte layers. In this process, the fabricated electrolyte layer is stored as a wound roll throughout the rewinding process. We analyzed the defects and geometric changes in an electrolyte layer, i.e., gadolinium-doped cerium oxide (GDC), due to the radial stress in the wound roll. We found that the thickness of the coated layer could be decreased by increasing the radial stress, i.e., cracks can be generated in the coated layer if excessively high radial stress is applied to the wound-coated layer. More thickness changes and crack defects were generated with time due to the residual stress in the wound roll. Finally, we analyzed the effects of taper tension profiles on the defects of the coated layer in the wound roll and determined the taper tension profile to minimize defects.

Web Wrinkle Defects due to Temperature Profile in Roll-to-Roll Manufacturing Systems

“…In this process, many webs are wound on one central core in the final product, thereby increasing productivity; however, the quality of the functional layer may be degraded if excessive radial stress is generated within the wound roll. Noh et al observed that radial stress increased over time due to residual stress and reported that the storage time of a wound roll needs to be minimized [ 27 ]. In particular, when the electrolyte layer manufactured by Roll-to-Roll slot die coating is stored in a compact wound roll form, it is confirmed that the thickness of the electrolyte layer decreases due to the excessive stress in a radial and hoop direction generated inside the wound roll as a large amount of web is wound.…”