Patch placements lighten the load

Powered by hydrogen, fuel cell electric vehicles (FCEV) out-perform battery-powered cars in several dimensions. Refuelled in only a few minutes, they have a longer range, and still feature all performance benefits of the electric powertrain.

But the technology is still young and has to master some challenges. From a composites’ point of view, the significant amount of fibres needed for the hydrogen storage vessel is a particular challenge. And it’s one that was taken into the focus of Cevotec’s engineers who designed a solution to save 20% of time, material and cost to build composites-based high-pressure vessels.

Cevotec enables manufacturers to build complex fibre composites in high volume and quality – by smart process automation based on Fibre Patch Placement (FPP) technology. With SAMBA Series, Cevotec offers a customisable fiber lay-up automation platform for challenging 3D geometries and multi-material laminates with complex fibre orientation. ARTIST STUDIO is the associated CAE software for generating patch-based fibre laminates and automated robot programming. Along with development services that include FEA-based modelling and simulation, Cevotec offers the entire process chain from digital design to final fiber product.

“The automotive industry has invested billions in fuel cell electric vehicles, but very few cars are in use on our streets,” says Thorsten Groene, CEO of Munich-based FPP specialist, Cevotec. “One of the larger challenges is to efficiently and safely store hydrogen in the vehicle. There is working pressure of up to 700bar in the tanks, which translate into approximately 10kg of carbon fibre for 1kg hydrogen storage – a very high ratio.”

Obviously, manufacturers are interested in using less of the expensive fibres to reduce the vessel’s weight and cost.

“Wrapping endless fibres around the liner is best for the cylindrical part,” says Dr Neven Majic, executive vice-president of Cevotec. “But filament winding around the domes means redundant material on the cylindrical part – which translates into excess weight and cost of the final product.”

Cevotec’s solution is to apply carbon fibre patches in the dome areas, using the same material, but just in patch form instead.

“The patches are designed to exactly cover the areas causing problems in filament winding,” explains Majic.

With patch reinforcements on the liner domes done in a first step, the patched liners are passed over to the filament winding process, which subsequently needs less material and production time for the dome areas.

Patching of the domes is done by Cevotec’s SAMBA Series production systems.

“The Fibre Patch Placement technology cuts patches from fibre material and places them individually on positions calculated by CAE software ARTIST STUDIO,” continues Majic.

Adds Cevotec’s Groene: “The investment in patch technology pays off from the first day of production. One FPP system can reinforce vessels for several winding machines. Manufacturers can realise at least 20% material and cycle time savings.

“When manufacturers combine winding and patch placement in series production, the FPP capital investment amortises within the first year already. It’s a fairly simple calculation that we present to our interested customers.”

By applying Fibre Patch Placement technology to today’s composite manufacturing challenges, Cevotec supports the advancement of composites for a green mobility revolution. Application areas for FPP also include many components in aerospace and new urban air mobility - all of which are currently produced manually. Cevotec says it has conceptualised a range of production cell configurations to match the manufacturing process to the different applications. Material efficiency and cost savings of 20-60% are typical benefits for manufacturers switching from manual lay-up to Fibre Patch Placement technology.

www.cevotec.com