Steel for bipolar plates
High-performance fuel cells form the heart of hydrogen-based drive systems. Our stainless precision steel strip is the perfect material for the cost-effective production of the metallic bipolar plates required for this purpose. This is because it offers excellent formability despite its extremely low material thickness.
In light of their long range and faster refueling compared to battery-powered vehicles (BEVs), the ongoing development of fuel cell vehicles (FCEVs) represents an interesting alternative in the carbon-neutral mobility mix. The bipolar plates that, in combination with the membrane electrode unit, form the individual cells within a fuel cell stack offer significant potential in terms of fuel cell efficiency and compact design. To take full advantage of this, an extremely thin material is required that reliably supports complex forming operations during the manufacturing process. Only on the basis of these material properties is it possible to manufacture highly efficient bipolar plate stacks that make it possible to achieve complex flow-field designs, the fine channels used to convey gas and coolant, even in small sizes.
Waelzholz offers stainless precision steel strip in thicknesses of only 50 to 200 µm (0.002 – 0.008 in) for the production of bipolar plate stacks. The advantage is that with over 800 individual plates needed to assemble one bipolar plate stack, the ultra-thin sheets collectively result in a compact design. Our special production routing also results in a material that exhibits ten percent better formability than the standard and is also extremely flat. This makes the material perfectly suited for the complex forming processes with tight bending radii used to create complex flow fields.
Customized topology as the basis for versatile coating systems to increase efficiency
To optimize the electrical performance of the fuel cells, the sheets for the production of bipolar plates are coated. By precisely calibrating the surface of the stainless precision steel strip, Waelzholz offers a customized basis for this purpose. The topology of the surface can be tailored exactly as required to achieve the best results with the customer’s specific coating. Another advantage of the material used is its resistance to corrosion – should the coating be damaged during further processing, the steel material, which is already stainless, prevents corrosion and thus a possible reduction in performance or even failure of the fuel cell stack.
Waelzholz’s bipolar plate steels offer a wide range of benefits for your application:
- Cost efficiency when using 1.4301, 1.4303 and 1.4016 by reducing alloying costs compared with 1.4404
- Our unique production routing improves the forming properties (Erichsen test) by 10% compared to the standard – making it possible to achieve the tightest bending radii and complex shapes with a high degree of isotropy
- Exceptional flatness for optimized flow-field forming over the entire plate surface as a basis for dimensional stability and durability in automotive applications
- Topology perfectly tailored to your coating
- Safeguard the functionality of the bipolar plate by protecting them from corrosion when using stainless precision steel strip, even if the coating is damaged
- Ideal workability and efficient processes thanks to highly consistent properties and a uniform thickness over the entire length of the steel strip
- Maximum precision through targeted limitation of the precision tolerance class
Request sample
Would you like to find out whether our stainless precision steel strip is also a good choice for your bipolar plate production? We invite you to request a sample of our 1.4301, 1.4303, 1.4404, or 1.4016 grades for initial testing purposes via the button to the right. Please specify the desired size when submitting your request.
Overview of primary materials and forms of deliveryStainless precision steel strip
| Condition | Microstructure | Thickness range | Tolerance class according to DIN EN ISO 9445-1 |
Bendability** | Formability*** |
Standard |
Austenite |
0.05 mm - |
Precision |
Bending angle α=180° |
9.2 |
Waelzholz BPP steel grades* |
Austenite |
0.2 mm |
≦ Precision |
Bending radius r=0 |
10.2 |
* BPP steel grades = Bipolar plate steel
** Mandrel axis longitudinal and transverse to the rolling direction
*** Erichsen cupping value (IE) [mm], at strip thickness = 0.075 mm, based on DIN EN ISO 20482
** Mandrel axis longitudinal and transverse to the rolling direction
*** Erichsen cupping value (IE) [mm], at strip thickness = 0.075 mm, based on DIN EN ISO 20482
Contact partners
Global Sales Stainless Precision Steel Strip
Ralf Sauer
Materials Technology Stainless Precision Steel Strip
Jan Ullosat
Successful together – use our materials expertise for your next challenge
We conduct a detailed materials consultation to provide you with comprehensive support in the implementation of your projects, from giving you greater freedom in your design process to optimizing your manufacturing processes and ensuring compliance with the highest standards of quality.