In our Graebener® application laboratory we are able to make your ideas tangible even before production. Our machinery used for prototyping is constantly being further developed in view of growing market requirements. Thus, we deliver tangible, high-quality results to verify the manufacturability of your bipolar plate design. To help you decide quickly and cost-efficiently whether your original design or our optimization ideas are actually feasible, this is examined using a selected area of the plate as test geometry – saving you time and money.
For verification purposes, we work with our own especially developed and patented machine concepts – consisting of Graebener® hydroforming press, Graebener® cutting system and Graebener® welding system – which are ideally suited for a wide range of plate dimensions and materials from a foil thickness of 50 μm and which can realize the narrowest radii.
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 – from smallest lot sizes to small series with capacities of up to 50,000 parts per year.
Our quality speaks for itself: so far, we have realized more than 85 customer designs and have produced more than 100,000 parts.
If you intend to set up your own production in the future, the process parameters from our application 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.
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 application 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®.
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 application 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.
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, 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 application 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.
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.
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.
The final inspection of each individual bipolar plate by means of leakage testing is essential for the functionality of a fuel cell 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.
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.
We have developed our patented Graebener® hydroforming press especially for the economic production of metallic bipolar plates and have made it ready for series production.
With our sandwich tool, several plates can effortlessly be produced simultaneously per stroke, e.g. the cathode and anode side.
Not only do we form your bipolar plate. As an experienced technology and system partner, we are also at your side for the subsequent cutting and welding processes. Benefit from our many years of practical experience.