Strip Coil for Bipolar Plates: A Key Component for Fuel Cell Efficiency

Hydrogen fuel cells are an emerging green technology, signaling the advent of eco-friendly energy systems. Critical components like bipolar plates and electrolyzers, which turn hydrogen into electricity, and fuel cell energy are important in powering our future. Selecting and engineering materials such as titanium and stainless steel are essential, given their role in enhancing fuel cell efficiency and longevity. This piece delves into the precision manufacturing of these components, highlighting the importance of selecting suitable precision strip alloys to overcome the operational challenges of fuel cells.

The Heart of Fuel Cells: Bipolar Plates and Electrolyzers

Bipolar plates and electrolyzers lie at the heart of hydrogen fuel cell technology; their significance cannot be overstated. These parts are crucial for fuel cells’ efficient and effective operation, which is increasingly regarded as a future cornerstone of green technology. Alloy selection and precision manufacturing of metals for these components is pivotal, uniting materials science and engineering to meet the exacting demands of fuel cell applications.

Bipolar Plates: The Conduits of Efficiency

Bipolar plates play a multifaceted role within fuel cells, distributing reactant gases evenly across the cell and facilitating the conduction of electricity within the fuel cell stack. Their design and material composition are critical for minimizing contact resistance and ensuring uniform current distribution. Materials such as stainless, nickel, and titanium strip are preferred for their excellent corrosion resistance, high electrical and thermal conductivity, and mechanical strength. The thickness of these plates is a critical design parameter; thinner materials allow for a compact cell design, significantly enhancing the fuel cell’s power density and efficiency.

Electrolyzers: The Hydrogen Generators

Electrolyzers serve a parallel yet distinct function in hydrogen fuel cells - they split water into hydrogen and oxygen through electrolysis. The efficiency and durability of electrolyzers depend on material choices, especially under harsh operating conditions. Further, material selection significantly influences corrosion resistance and the thermal and electrical conductivity of the cell. Both are essential for the efficiency of the hydrogen generation process.

Advanced Manufacturing Techniques: A Necessity

Sophisticated manufacturing techniques are needed to produce these critical components requiring high precision and performance. For instance, automatic gauge control systems in rolling mills are instrumental in producing light-gauge materials with high precision. The surface finish of these materials is also critical, as it directly impacts the contact resistance between the bipolar plates and the Membrane Electrode Assembly (MEA), thereby affecting fuel cell efficiency. Very few precision rerollers in America can produce materials that meet the needs of this application.

Different fuel cell technologies and their respective applications require different finishes on bipolar plates. Maintaining a uniform and consistent surface is essential, as any deviation in quality is significantly amplified throughout each stack. Moreover, the surface finish plays a vital role in enhancing corrosion resistance. This highlights the importance of obtaining fuel cell materials from suppliers with the capability to manage material surfaces effectively.

For optimal results, Fuel Cell Manufacturers (FCMs) should seek partnerships with suppliers with a robust and varied supply chain to secure metal that aligns with their specific needs. While re-roll mills are adept at producing precise surface finishes, it’s worth noting that Service Centers can also contribute effectively in this area. Companies like Ulbrich work in close partnership with different melt mills and service centers to provide a wide range of alloys, including those with custom finishes designed to meet the unique demands of their applications and manufacturing processes.

Challenges in Fuel Cell Environments

Another battlefront engineers face in developing fuel cell technologies is finding materials capable of withstanding the internal conditions within fuel cells. Acidic environments and temperatures exceeding 200°F mark the internal conditions within fuel cells. This demands corrosion-resistant alloys. Additional complicating factors, such as thermal cycling, oxidative conditions, and electrolyte contamination, present significant challenges to the durability and performance of fuel cell components, particularly bipolar plates.

Collaboration between component engineers and metal suppliers helps tremendously in navigating these hurdles successfully.

Collaborative Solutions for Material Challenges

Success in fuel cell technology often hinges on joint efforts with material suppliers. Strong alliances that draw on comprehensive materials science knowledge, understanding of fuel cell mechanics, and expertise in precision manufacturing foster innovation that the rest tend to miss. The ability to work closely on developing custom alloy properties tailored to specific efficiency goals and operating conditions is a critical capability of a fuel cell materials supplier.

Using meticulously engineered materials for components such as bipolar plates and electrolyzers is critical in addressing the environmental hurdles of fuel cell technologies. Innovations in material science and advanced manufacturing techniques enhance fuel cells’ durability, efficiency, and performance, paving the way for their broader adoption in clean energy solutions. To realize this future, FCMs and metalworkers must be close allies.

Criteria for Selecting Alloys for Bipolar Plates

• Mechanical Strength: It’s crucial that the bipolar plates can endure the stress and pressure within the fuel cell stack without deforming. This ensures the cell’s internal architecture retains its integrity for uniform performance.
• Conductivity: High electrical and thermal conductivity are essential for efficient electron and heat transfer within the cell. Materials with high conductivity help cut energy losses and improve the efficiency of the fuel cell.
• Low Magnetic Permeability: Ideally, materials should possess minimal magnetic permeability to prevent disruptions to the fuel cell’s electric and magnetic fields, which may otherwise impede the energy conversion process.
• Corrosion Resistance: Considering the often acidic conditions within fuel cells, materials must be highly corrosion-resistant to secure a longer service life and consistent output.

The Importance of Thin Plates for Efficiency

For optimal fuel cell efficacy, utilizing extremely thin bipolar plates is essential. Reduced thickness leads to a more condensed cell design, enabling a higher density of power-generating membranes within the same volume. Focusing on this aspect improves efficiency by maximizing the area available for electrochemical reactions while reducing the overall weight and size of the fuel stack.

Precision Manufacturing: A Necessity for Performance

Manufacturing these thin, high-performance bipolar plates requires advanced precision engineering techniques. Achieving and maintaining tight tolerances in thickness and uniformity across the plates is essential for ensuring consistent performance throughout the fuel cell stack. Advanced rolling, stamping, and finishing techniques meet these stringent requirements, ensuring that each plate meets optimal fuel cell operation specifications.

Ulbrich Stainless Steels & Special Metals is the development partner of choice for many visionary organizations paving the way for the future within the fuel cell market. Our metallurgical engineering and product teams help organizations strike the careful balance of strength, conductivity, magnetic permeability, and corrosion resistance required for producing ultra-thin bipolar plates. With over 100 years of experience in metal manufacturing, Ulbrich is an expert in navigating the complexity of material selection in fuel cell technology.