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Compared with traditional machine processing and pressing, Cell Impacts method makes it possible to dramatically reduce production costs for flow plates for fuel cells and heat exchangers, without limitations in the choice of material or the plates efficiency.
Machining
Using modern equipment for milling, blasting, etching or laser cutting, flow plates can be produced efficiently from virtually any material directly from a computer model. The disadvantage is that the manufacturing time is long and amounts to anywhere between several minutes to several hundred hours which involves very high processing costs. The method is therefore well-suited to prototype manufacturing but lacks large scale advantages.
Pressing
Pressing of plates can be done by pressing either powder or solid metal. Powder pressing of graphite and polymers is a proven method. The inherent porosity that results from powder pressing must however be compensated by thicker plates or repeated press operations so that the plate will be dense and not leak gas.
Pressing of metal is limited by the complexity of the pattern required. None of the methods currently available for pressing of metals such as stainless steel or aluminium has proven to meet precision requirements. The method can be used for production of low-performance plates and is thus appropriate for applications where the fuel cells total size or weight is not significant.
Both pressing methods have a high initial cost for tooling, which makes certain volumes necessary for it to be economically viable. In line with increasing volumes the price per plate falls.
Metal or powder moulding
Metal or a mix of powders is injected in a moulding form at a rate of between one and six plates per minute. The primary disadvantage is that the method requires a large amount of binding agent that increases the material costs, lessen the plates conductivity and reduces its ability to resist gas leakage. Moulding is best suited to production of small low-performance plates. |
