In order to develop new coating materials or modify existing products there must be systems in place to trial and to coat materials uniformly and with consistent coat weight regardless of the application. In the production of batteries, thinner filmic webs are necessary for them to function effectively for longer periods and at higher power output. The same is essentially the case with other energy-generating devices such as fuel cells.
The thickness and stiffness of a substrate surface is just one of the processing conditions that can impact coating quality and performance. Substrates may exhibit the same degree of thickness but extensibility and stiffness may vary greatly. Thinner substrates and thinner coating flows may require higher tension levels. Fuel cells differ of course from batteries such as lithium, alkaline and Ni-Cd’s in that they never run down or need recharging. Fuel cells use the chemical energy derived from hydrogen or another fuel to cleanly and efficiently produce energy. They generate electricity as long as fuel such as hydrogen is supplied. Lower emissions and the fact that they can be used for applications as diverse as transportation; power station supply; medical diagnostic equipment and communication systems and computing. These applications just hint at the possibilities and market potential for fuel cells.
Issues still need to be overcome
Cost, performance and issues surrounding durability still need to be overcome. Research and development is ongoing and involves manufacturers, technical institutes and government agencies. All organisations associated with energy and in partnership to meet the objectives associated with fuel cells and other eco-energy alternatives. Quality control devices, and bespoke pilot/production coating systems play an important role in bringing products such as batteries and fuel cells to market. All coating methods provide an inherent uniformity that they can achieve. If the applicator selected is inappropriate the end product will be unacceptable.
Slot die coating can be ideal where very thin or optically clear coatings need to be laid down. Slot die, one of the selectable coating technologies available with the VCM and VCML pilot coater machines is used to apply fluids or polymers such as adhesives, inks and electrolytes onto continuous thin substrates and which may be used in product areas such as electronic displays, medical patches and in battery production. Unlike many coating technologies that are open to the air, slot die provides a closed-loop delivery path and a more sterile coating environment with minimal evaporation.
Bespoke machines for R&D
RK Print Coat Instruments Ltd has supplied customer bespoke VCM pilot/production machines for customers involved in research and development; the trialling of materials and components associated with batteries and fuel cells. The VCM incorporates high-specification drives, tension and web control equipment with processing accessories supplied appropriately and as specified by the customer. A rigid framework serves as the foundation for the VCM, enabling the processing of wider web-width materials and if required, the handling of heavier-weight materials. Designed and developed with future proofing in mind the structure of the VCM provides the flexibility to expand or modify the machine as processing or product needs change.
Apart from slot die, the VCM can be supplied with flexo; gravure (direct, offset, etc.,), knife-over-roll, reverse roll, meter bar, extrusion coat and much more. The VCM can be configured for clean room conditions and drying/curing options include hot air, IR and UV.
Written by Tom Kerchiss, chairman of RK Print Coat Instruments Ltd