Faradayic ElectroEtching of Stainless Steel Bipolar Plates

Commercialization of polymer-electrolyte-membrane fuel cells requires low-cost components, materials, and manufacturing processes. However, current bipolar plate manufacturing methods are slow, expensive, and are inappropriate for some advanced flow-field designs. This project will develop an innovative electro-etching process that will enable through-mask etching of stainless steel bipolar plates at high volume and low cost. This technique will enable advanced flow channel designs, not easily attainable using current manufacturing technologies. In Phase I, an advanced electrochemical cell, which facilitates uniform flow across the entire surface of the test plates, was designed and modified to electro-etch a 2¿ x 2¿ serpentine flow field into 4¿ x 4¿ 304 and 440C stainless steel substrates. A preliminary economic analysis demonstrated that the innovative electro-etching process can meet the high volume cost target of ~$1.50 per bipolar plate. Phase II will (1) validate the development, optimization, and manufacturing of the electro-etching process for both gas and coolant flow field channels; (2) select appropriate tests to characterize the functionality, durability, and performance of the metal bipolar plates for single and short-stack fuel cells; and (3) conduct a more comprehensive economic assessment of the electro-etching process as it relates to bipolar plate manufacturing. Commercial Applications and other Benefits as described by the awardee: An electrochemical etching processes for passive materials such as stainless steels, titanium, and nickel-based alloys should have wide applications in a variety of industries, including aerospace, medical, and automotive. With respect to the manufacturing of fuel cells, the proposed process for bipolar plates should facilitate the viability of polymer-electrolyte-membrane fuel cells as a power source, reducing pollution and increasing manufacturing job opportunities in the U.S