Automotive grade graphene: the clock is ticking

David Isaiah investigates the viability of graphene in automotive manufacturing

Although the market for graphene is in its infancy, an increasing number of suppliers are expected to drive investment over the coming years. This is likely to result in a wider adoption of graphene. While North America currently dominates this market, a report by Visiongain suggests that Asia-Pacific will be the fastest growing region for the adoption of this material.

“For 2015 we forecast the global graphene market to reach US$24.4m. However, high costs, the fear of the unknown, immaturity of the market, poor knowledge and difficulty with mass production will be the main growth restraints that may result in a number of current companies going bankrupt in the coming years,” the report states. On the basis of graphene’s superior properties alone, there is likely to be a strong growth in demand for the material – in the longer term.

Graphene’s properties are astonishing. A million times thinner than a human hair, yet stronger than diamond and 200 times stronger than steel, graphene is the world’s thinnest, strongest material; it’s also an efficient conductor of heat and electricity, it’s very flexible, and it’s very light. Not surprisingly, it’s being hailed as a likely disruptive technology in many industries – including automotive.

Applications in the automotive sector

The potential applications for graphene are many, but there are currently none being marketed in the automotive sector. However, research activities are under way to study the material’s potential, and all stages of the automotive value chain need to be involved in this effort.

One of the most immediately likely applications for graphene-based products in automotive applications is in composite materials. Professor Ahmed Elmarakbi is a Professor of Automotive Engineering at the University of Sunderland in the UK, Founding Editor-in-Chief of the International Journal of Automotive Composites, and a Member of the EU Graphene Flagship. He told Megatrends that graphene has tremendous potential for the automotive industry, where it could be used to enhance the composite materials in cars.
Thanks to the anticipated future demand for lightweight vehicles, the automotive industry is expected to be the highest user of advanced composite materials by volume, said Elmarakbi. “Nowadays, several advanced materials are widely used in the automotive industry, but vehicle safety is usually compromised by lightweighting. Due to the trade-off between light vehicles and safety standards, new directions need to be adopted to overcome safety issues. Several attempts have been made to strengthen vehicle structures to enhance crashworthiness, but safety issues remain the main obstacle to producing lighter and greener cars.”

Unsurprisingly, cost is one of the most challenging aspects of adapting graphene for automotive applications, and it will require collaboration across the entire value chain to reduce as much as possible the manufacturing costs associated with using this material.

Research has revealed that dispersing a small amount of graphene in polymers can significantly improve many properties of the resulting composites, such as tensile strength and elastic modulus, electrical and thermal conductivity, thermal stability, gas barrier, and flame retardancy. Based on these multifunctional properties, graphene/polymer composites are promising as both structural and functional composites, with integration of functionalities within the automotive sector.

Lightweight graphene based components by Fiat
Lightweight graphene based components by Fiat

 

Challenges

While graphene is in the long term expected to offer a wide number of solutions, numerous challenges have to be overcome even in developing a fundamental understanding of graphene related materials (GRM) and their polymer composites. One of the challenges that automotive engineers and researchers face is the lack of new methods of large scale production of graphene-based products, especially since mechanical exfoliation is not scalable to an industrial process.

Frank Macher, Chief Executive Officer of Continental Structural Plastics (CSP), a US-based supplier of composite materials, said at Automotive Megatrends USA 2015, an annual conference held in Dearborn, Michigan, that at the present time, no methods exist for the mass production of graphene, “But once that is figured out, there are great possibilities for sustainable and substantial weight reductions in future.

“We are working with the University of South Dakota, and they have been studying graphene for some period of time. One of the biggest problems with graphene is the absolute challenge of producing it in any kind of quantity,” he told Megatrends.

Other challenges include a lack of new methods of functionalisation; investigation of the exfoliation process of graphene-based material during the process; insufficient knowledge around attainable strength/stiffness of graphene thermosets/thermoplastic polymer composites; the absence of a materials model for understanding graphene-based composite materials for high performance structural applications; etc. The list goes on.

There are also some challenges that are very specific to the use of graphene in the automotive industry. For instance, there is the matter of expected low ductility of graphene-based composite structures. Considering implementation on several vehicle components (i.e. front end), this will lead to high vehicle deceleration, something which minimises vehicle safety. There is also a lack of knowledge around on how to design graphene composite automotive structures that can offer high stiffness, strength and predictable and safe failure modes.

“In addition to the above challenges, a large amount of work remains to be done to develop a practical, reliable and capable tool to analyse and design the new graphene-based polymer composites and study the crashworthiness optimisation for its structures and their applications in the automotive industry. The graphene-based polymer composites are still in infancy stage with regard to high-performance structural applications,” said Elmarakbi.

“There are no theoretical studies available in the technical literature on dynamic analysis and crash behaviour, as well as the fracture and failure behaviour of graphene composites under severe loading conditions typical for automotive applications. The reliability of determining the homogenised response of such materials depends upon the ability to accurately capture the interfacial behaviour between the graphene and the polymer matrix,” he told us.

The Graphene Flagship

Launched in 2013, The Graphene Flagship is the EU’s biggest ever research initiative. With a budget of €1bn (US$1.14bn), it represents a new form of joint, coordinated research on an unprecedented scale. The Graphene Flagship is tasked with bringing together academic and industrial researchers to take graphene from the realm of academic laboratories into European society in the space of ten years, thus generating economic growth, new jobs and new opportunities.

Elmarakbi is the leader of Graphene Flagship: Task 10.11, Composites for Automotive. The group’s current work in Task 10.11 within WP10 (Nanocomposites) advances innovative lightweight graphene-based materials and their related modelling, designing, manufacturing and joining capabilities suitable for the automotive industry, which requires unique levels of affordability, mechanical performance, green environmental impact and energy efficiency. According to Elmarakbi, it also revolutionises computer-based as well as experimental validation approaches, and their combinations, to allow for a fast, efficient and reliable development process.

“We are expecting huge success for graphene as a main player on developing composites for automotive applications,” he told Megatrends. “Our goal is to combine these novel materials concepts with the latest safety design approaches through the development and optimisation of advanced ultra-light graphene-based polymer materials, efficient fabrication and manufacturing processes, and life-cycle analysis to reduce the environmental impact of future vehicles.”

Before anyone even begins to think of the use of graphene in vehicles featuring composite structures, it must be emphasised that impact resistance and crashworthiness optimisation studies of advanced composite components remain at an early stage. A large amount of work still remains to be done to develop a practical, reliable and capable tool to analyse and design the new graphene-based polymer composites and study the crashworthiness optimisation for its structures and their applications in the automotive industry. This also requires an affordable, large-scale production process for graphene-based products.

Other lines of thought for graphene use

Used on its own or in conjunction with other materials or substances – there is no doubt that the possibilities for this material are vast. One line of thought is that graphene could be used to protect steel from corrosion. Tata Steel, along with the Engineering and Physical Sciences Research Council (EPSRC) in the UK, has been studying graphene-based steel coatings, which could potentially be used in a number of applications, from automotive lighting to solar energy systems, thanks to its high levels of electrical conductivity.

Future direction

The research and development required to make graphene a viable manufacturing material is considerable. Work is needed to understand the behaviour of these material systems in most suitable joining methods, and advancements in joining technologies are required to develop realistic industrial solutions which can reliably and repetitively join a variety of materials.

More work needs to be done to “increase reliability in service and improved crashworthiness including protection of vulnerable road users, through the application of the developed graphene-based composite materials and implementation of advanced energy absorption capabilities, enabling the application of next-generation materials in safety-critical parts,” explained Elmarakbi.

One aspect repeated over and over is that of developing high throughput manufacturing technologies for advanced lightweight graphene composite materials, which would achieve lower costs and increase economic viability. However, given that even composite materials used in the automotive sector, such as carbon fibre reinforced plastic (CFRP), still cost much more than conventional materials, it will be some considerable time before automotive graphene use becomes a reality.

David Isaiah

This article appeared in the Q2 2015 issue of Automotive Megatrends Magazine. Follow this link to download the full issue.

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