Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Polaris (Lighter, Cheaper Thermoplastic CNG Tanks for Automotive & Commercial Vehicle Markets)

Teaser

What is the problem/issue being addressed?CNG (Compressed Natural Gas) tanks are used in 1.3 million vehicles in Europe (24 million worldwide ) and are typically made from a metal or polymer liner, over-wound with a carbon/epoxy thermoset composite which carries the pressure...

Summary

What is the problem/issue being addressed?
CNG (Compressed Natural Gas) tanks are used in 1.3 million vehicles in Europe (24 million worldwide ) and are typically made from a metal or polymer liner, over-wound with a carbon/epoxy thermoset composite which carries the pressure loads.
However, carbon/epoxy composites are not ideal. The process coats carbon fibres with a liquid epoxy resin and immediately applies them to the liner, where the epoxy reacts and hardens. This wet winding process results in inconsistencies in the epoxy matrix and misalignment of the carbon fibre, giving up to 10% variation in tank burst pressure. More material is therefore added to compensate, increasing cost and weight, and the process is also slow, with a rate of typically just two 52-litre tanks per hour.
One alternative is to manufacture carbon/polyamide thermoplastic tapes, and subsequently heat and apply them to the liner in a high-speed winding process. This process has the potential to overcome the variation in wet-wound epoxies, but material manufacturers have not previously been able to make tapes of high enough quality, and vessel manufacturers have not been able to wind them efficiently.
To overcome this problem, Coventive Composites has developed an improved impregnation process to make carbon/polyamide tape with lower voids and less variability in performance. In parallel, MF Tech has developed a robotic winding process to double the production speed, so that Plastic Omnium can efficiently manufacture CNG tanks with carbon/polyamide thermoplastic tapes.
This new thermoplastic tape, robotic equipment and winding process allows the production of higher quality over-wound pressure vessels, reducing variation in tank burst pressure to 5% (compared to epoxy at 10%). This enables less material to be used, saving both cost and weight – a step change in the CNG tank market. Plastic Omnium’s testing has shown that these pressure vessels can meet (and exceed) the targets set by their customers, reducing weight by 10% and reducing cost by 20%.

Why is it important for society?
By developing a new generation of CNG tanks, this project supports the aim of the European Alternative Fuels Strategy , to meet the EU challenges of oil dependence, emissions, pollution and competitiveness, and to overcome the challenges facing EU transport systems :
• Reduce the EU transport systems oil dependence in order to diversify and secure energy supply
• Reduce EU GHG emissions in line with the 20-20-20 Climate and Energy Package and the 2011 White Paper on Transport
• Improve the air quality in urban areas in order to meet EU air quality obligations
• Enhance the competitiveness of European industry, boost innovation and generate growth
The strategy document established a coherent policy on alternative fuels to support the market, remove technical and regulatory barriers and guide development and investment. CNG forms an integral part of this strategy, ensuring that developments in CNG vehicles are supported by parallel developments in CNG transportation (e.g. refuelling points), standards and consumer information.

What are the overall objectives?
The tape, winding process and pressure vessels have so far been demonstrated on a prototype scale, and the specific objectives of this project address 3 key barriers to commercialisation:
• Optimise and upscale the tape process to meet cost, processability and property requirements.
• Enhance the vessel-winding process to meet performance, weight and productivity needs.
• Upscale the manufacture of carbon/polyamide CNG tanks, to enable economic production.
This project will advance the development to TRL 8, meeting our customers’ cost and weight targets, with demonstration of the complete system (material, process, product).

Work performed

Plastic Omnium is working continuously with potential customers to ensure that the project is targeted to their requirements on performance, processability and cost. A commercialisation plan has been updated throughout the project. Key Exploitable Results have been identified and options for their protection are continuously under review.

We have tested and refined polymer formulations to meet customers’ requirements on processability of the material, overall performance and laying speed. This work has clearly demonstrated the most suitable polymer formulations to take forward. However, work will continue at Coventive Composites in order to fine tune the materials for large scale production.

Investigations have taken place to refine the best way to lay the tapes and the equipment requirements for this operation. The process has been simulated to provide the optimum laying strategy and various heating sources have been evaluated. Although the objectives have been achieved, work will continue in order to fine tune the process for large scale production.

Work has started related to the upscaling of the tape production process and some of the parts have been ordered..

Finally, the outputs of each development stage have been assessed positively against the targets for processability, performance and economics. The results have been used to steer the process development.

Final results

The results achieved so far are all inline with the expected impacts for the project. Specifically, the materials and processes being developed will enable Plastic Omnium to develop a CNG tank fit for purpose. With these changes they will improve their economic (cheaper processing), environmental (lighter parts) and social (safer working practices - less solvents) performance as part of a business improvement. The initial technical work has achieved all the objectives set and we are now moving to the next stage of upscaling the process.

Website & more info

More info: https://polaris-project.org.