International pressure for energy diversification has led to a dynamic investment environment for alternative energy choices, with fuel cells being the most efficient. The global fuel cell market is projected to reach over $25 billion by 2025.
The increasing demand for more efficient and cost-effective fuel cells will influence the choice of materials and the selected manufacturing technologies.
Traditionally, bipolar fuel cell plates are CNC machined. Graphite, being a very expensive and highly permeable material, is unsuitable for large-scale production applications. Many materials have been evaluated as alternatives, and durable materials, particularly stainless steel and titanium, have become increasingly popular due to the need for competitive pricing and relative ease of manufacture. Stainless steel possesses a range of properties that make it well-suited for bipolar fuel cell plates, including inherent strength, chemical stability, low cost, and relative ease of mass production.
Fuel cells are made by stacking intricately designed plates with complex grooves or channels that allow liquids and gases to flow. They can be manufactured in various ways using CNC machining and stamping techniques, but the scalability and functionality of these processes remain questionable.
Traditional metalworking techniques, such as stamping—and more recently, hydroforming—impair flatness and introduce stress and burrs. Single-point machining processes and stamping tools can also be slow and uneconomical to produce, especially during the research and development process.
The little-known photochemical etching process offers manufacturers a significant advantage when manufacturing complex components such as bipolar fuel cell plates.
First and foremost, photolithography requires no hard tools, and the use of digital tools is inexpensive for production and adaptation, thus allowing for design optimization at minimal cost.
This process also allows for rapid scaling from prototype batches to mass production, offers virtually unlimited part complexity, produces burr-free and stress-free components (especially important for fuel cell panels where imperfections can compromise stack bonding), does not affect metal tempering and properties, is applicable to all grades of steel, and achieves an accuracy of ±0.025mm – with all delivery times measured in days rather than months.
Photochemical etching removes metal simultaneously, meaning complex channels or flow fields can be etched on both sides of a board. This versatility allows designers to change the size and shape of the channels and incorporate manifolds, collectors, and port functions without incurring additional costs, something other technologies cannot achieve.
PrecisionMicro typically uses 316 or 904 grade stainless steel to manufacture bipolar plates, with a plate size of 1500mm x 600mm. However, plates can also be specified using special difficult-to-machine metals (such as titanium) to reduce weight and improve corrosion resistance under high strength. Applications include temperature-sensitive fuel cells.
The versatility of photochemical etching makes it an attractive option for manufacturing complex sheet metal parts in a wide range of complex applications, and it inspires innovation by eliminating the design barriers inherent in traditional technologies.
