Small Series Production of Bipolar Plates

Production laboratory for small series production of bipolar plates - scope of services

• Before you take the next step and invest in your own Graebener manufacturing technology, we would be pleased to support you in the production of your plate within the scope of our pre-buy services.
• We produce smallest lot sizes and small series with capacities of up to 50,000 parts per year.
• Our quality speaks for itself, so far, we have realized more than 90 customer designs and have produced more than 110,000 parts.
• If you intend to set up your own production in the future, the process parameters from our production laboratory can be transferred one-to-one to your own Graebener lines.
• From the initial consultation to the feasibility analysis and tooling up to the optimal production, our experience is incorporated into your individual line solution.

Service features

• Material: In the production of bipolar plates, the market generally focuses on stainless steel. We think in terms of material: In particular because, for instance, materials with a thickness of only 50 µm are used in electrolysis, or titanium is used as well, we provide a decisive added value with our material know-how. From knowledge about the behavior of different materials in the forming process to the evaluation of performance in processing – with our production laboratory we provide you with certainty in terms of materials for the production of your bipolar plates right from the start. No matter whether you want to process stainless steel, titanium, copper, clad or pre-coated materials, such as Sandvik Sanergy LT.
• Forming: Since there is still no product standard for bipolar plates, we remain flexible in terms of production right from the start. Together with you, we determine the limits of the geometries that can be formed in order to realize your design as precisely as possible. This also applies to the dimensions of your plates. Whether thinnest materials from 50 µm or plate sizes of up to 2,500 cm², we have the flexibility to react to your specifications by hydroforming in our production laboratory. Furthermore, we realize a wide variety of test geometries in a vast range of sizes for you, in order to determine the possibilities of forming to their limits as well.
• Cutting: Since the cut edges of the single resp. bipolar plates are used, among other things, as alignment elements in downstream processes and any deviation between the cutting contour and the formed channel structures can lead to problems during the operation of the fuel cell or electrolyzer, special precision is required when cutting the plates. Likewise, the quality of the cutting edge has a significant influence on the quality of the final product. With laser fusion cutting, we use a process in our production laboratory that achieves precisely this high level of accuracy and quality. And this is achieved without significant maintenance costs or tolerance problems due to tool wear. This ensures fitting accuracy even for complex structures.
• Welding: For welding the plates, we rely on our proven laser scanner technology. In this welding process, the laser head is not moved mechanically, which is time-consuming. Instead, the beam is directed to the respective welding spot via a mirror system. Due to the static structure of the laser, our welding technology allows for extremely high speeds and thus saves valuable time for you. At the same time, the smallest spot sizes of the laser beam ensure that we also weld reliably in the channel structures.
• Straightening: With our specially developed and worldwide unique technology for straightening metallic bipolar plates we enable you to reduce warping and to produce flat bipolar plates. This is a necessary requirement for both economical stack production as well as high performance and durability of the stacks. The straightening process is contactless and neither influences the surface and a possible coating nor the moulded geometry of the metallic bipolar plates.
• Measuring/testing: Precise measuring methods are decisive for evaluating the quality of a bipolar plate. The quality, however, is measured in the precision of the channel structures, wall thickness homogeneity, flat contact surfaces, clean cutting edges and pinpoint welds. By means of microsection preparation, we check these parameters and can thus evaluate the quality and characteristics on a microscopic level.
• Leak tests: The final inspection of each individual bipolar plate by means of leakage testing is essential for the functionality of a fuel cell or electrolysis system. Even a single leaking plate would lead to a failure of the stack and consequently of the entire system. Therefore, all plates manufactured in our application laboratory are subject to a 100% leakage test. In this process, compressed air is applied to the individual media areas of the welded bipolar plate in order to check them in terms of leak tightness.
• Coating: Hydroforming is ideal for us as a forming process due to the fact that the pre-coating of the plates is not damaged by the absence of mechanical action. The quality remains unaffected since the forming process has no influence on the pre-coated materials. However, should you require a post-coating of the formed or even finally welded bipolar plate, our partner network is at your disposal for this purpose.

Application areas

• Engineering of producibility from CAD designs
• Production of metal bipolar plates for fuel cell application
• Production of metal separator plates for electrolysis application
• Production of metal bipolar plates for heat exchanger application

Contact us

• Let us help you out in getting the most efficient small series production service.