Community Research and Development Information Service - CORDIS

FP7

UltraWire Report Summary

Project ID: 609057
Funded under: FP7-NMP
Country: United Kingdom

Final Report Summary - ULTRAWIRE (Ultra Conductive Copper-Carbon Nanotube Wire)

Executive Summary:
The most common traditional materials used in electrical energy distribution systems are copper and copper alloys. Modern applications show an increasing demand for better heat and electric current carrying capacity at the level beyond copper base materials. Nanocarbon materials, such as carbon nanotubes and graphene have attracted attention due to their high electrical, thermal conductivity and exceptional mechanical properties. It would appear that combining copper with high performance nanocarbons towards composite materials could offer immediate solution to problems encountered currently. Copper nanocarbon composites could form the next generation of conductors, where copper contributes the benefits of electrical conductivity, whereas nanocarbon brings to this composite its low weight, flexibility, mechanical reinforcement and thermal management. Recent breakthrough in the chirality control of carbon nanotubes could contribute significantly to the electrical conductivity of these composite materials beyond the performance achieved by bulk copper conductors.
The material and process costs required to achieve improvement of the overall performance of copper based electrical conductors, need to be compatible with large scale conductor manufacturing and overcome the issues such as the cost of the nanocarbons and the difficulty of scaling up the production processes.
This project is aimed at developing a copper nanocarbon composite wire with significantly improved overall properties, including electrical, thermal and mechanical performances over bulk copper. The project will also explore different ways of copper wire manufacture and develop the most promising process to large volume manufacture.

Project Context and Objectives:
The project has been following the main timeline and schedule required to succeed with the objectives and deliverables set by the consortium members. All the consortium members were very committed to the project to deliver the maximum output possible. Extensive efforts were placed initially on producing carbon nanomaterials with different morphology and form of assembly followed by the optimisation of the interface between copper and nanocarbon and optimisation of the copper composite wires. The demand for nanocarbons was initially high and it was difficult to suddenly produce large volumes however the production was managed so that constant supply was delivered to everyone using relevant materials so that the initial trials could start within respected work packages. There was also intensive characterisation carried out on the different batches supplied to the consortium partners to ensure that the structure of the nanocarbons is closely correlated with the performance observed in the composite conductor.
An important area of development was the interface studies, to support the understanding of the interaction between nano-structured carbon and copper. The plan was to start with direct interaction between CNT and pure copper, which served the consortium as a bench mark for subsequent tests. The surface of carbon nanotubes was modified to improve the copper interaction and study its effect on the electron transfer between these different materials. A breakthrough was achieved within this project, which demonstrated a significant wetting of copper on as-produced carbon nanotubes. The interaction was found to be so strong that it enabled copper infiltration even into small interspaces between individual nanotubes. The experimental work was fully supported by the modelling package introduced in the project. The modelling work enabled understanding of results observed in the project at the atomistic and electronic level. It also allowed tuning of the composite performance during the scale up phase and saved significant efforts by some of the consortium members. The consortium partners agreed on protocols to measure resistance, specific electrical conductivity, ampacity, creep, tensile strength and coefficient of thermal expansion on representative wires produced during the project. The measurements of specific values will avoid some errors, relating to the estimation of wires diameter. Several members of the consortium put efforts to built different ampacity setups. This approach allowed comparison of conductors under different laboratory conditions and verification of claimed performance. Significant improvement of ampacity was observed on specially formulated CNT/copper conductor and CNT/copper composites.
There were two areas particularly strongly developed within this project, initially outside the scope of the work, but indicating important directions of development. These are the powder metallurgy direction of uniform composite generation and direct copper/CNT wire conductor.
The electrodeposition of copper was explored in details and optimised particularly towards the end of the project. Initial wires prepared based on individual carbon nanotube fibre were found challenging due to the size of the fibres and complexity of plating conditions. Full penetration of copper in the fibre with lower density of the structure was successfully demonstrated however the mechanical stability of such structure was very low. Subsequently much thicker fibres were used to produce wires and the parameters of copper penetration were developed for uniform copper distribution. The team presented a detailed understanding of the science related to the copper deposition process on nano structured carbon materials. The conditions of the plating where optimised to yield a plated wire with very uniform coating of copper and very densely presented structure. However the performance of these type of composites was clearly the lowest out of all tested due to the granularity of the copper structure formed.
In the die-casting bulk processing of copper carbon composites, the initial work was devoted to build the improved wire production system. A dedicated system was commissioned and various diameter copper wires were produced and tested. Those were of good copper characteristics. The system was equipped with a special mechanical mixing setup to efficiently introduce nano carbons into the copper matrix. Modelling work was done on the geometry of the die-casting, in order to understand the wire formation process, particularly related to the controlled crystallisation. However the challenging part of the process was to obtain a composite with carbon nanotubes uniformly distributed in the copper matrix to generate composites with superior performance. Independent casting tests were carried out by 3 members of the consortium and all experienced dispersion problems during the process of casting. A large scale casting system has been also developed which successfully prepared composite wires towards the end of the project, with very successful stabilisation of carbon nanotubes in the copper matrix. This approach opens up a possible route for large bulk manufacture.
In parallel to the wire development work, other work packages were successfully developed representative life cycle analysis map, to understand better the methods of recyclability of such composite materials. Also the safety of material handling and processing was a very important part of this project and detailed assessment of the handling of nanotubes and the methods of their inclusion into copper were carried out in the real life scenarios and at different sites. The safety protocols were developed with proper operational assessments and visits to the future nano carbon/copper composite production sites.

Project Results:
Throughout the project there was a close monitoring of industrially viable results which can be taken forward by the main party involved or by any partner interested in the development. The Exploitation & Dissemination Plan Survey was designed using EUSurvey website tool for online surveys. During the project the survey was distributed to all partners and subsequently answers were received and collated. The aim of this survey was to collect information for the Exploitation & Dissemination Plan. The same approach was repeated at the end the project which resulted in fully updated information for the Exploitation & Dissemination Plan. Additionally, a group discussion was carried out to obtain Key Exploitation Results (KER) of all partners during the Exploitation and Disseminating Plan Workshop facilitated by Cambridge Nanomaterials Technology. Finally, at the end of the project, at month 36, partners were given an opportunity to update the KER table and asked about the overall project impact related to their organisation. Information about the field and planed patents and publications was monitored throughout the project by the project management committee and discussed between partners to protect innovation and explore the maximum commercial output from the project.
The project had two Open Day Workshops with representatives from very large industrial groups, and many other external delegates keen to engage with the material developed in the project.

Potential Impact:
The project contributes directly to a reduction in raw material consumption through reduced copper content. In Europe ambitious targets have been set for integrating renewable energy sources, reducing greenhouse gas emissions and improving energy efficiency.
Ultrawire will offer reduction in energy losses at all stages of the infrastructure, which for the UK transmission and distribution system are approximately 7% (this figure excludes losses within the electrical systems of the generators themselves and further losses within the wiring systems of consumers and in their appliances).
Electrical applications account for approximately 60% of copper consumption. The presence of carbon nanotubes within the conductor is expected to have big impact on:
(a) immediate reduction in the import of cathode into the EU owing to the reduce copper requirement for a specified current carrying capacity
(b) improving the efficiency of electrical machines
(c) the possibility of using a greater proportion of recycled material in electrical applications
An average car contains between 20 kilograms and 45 kilograms of copper wire. Depending of the used manufacturing process, by using carbon nanomaterials we will be able to reduce the weight of copper wires significantly. It would mean that only the use nanocarbon-copper wires could reduce the car weight significantly. According to the Ricardo Weight Savings Study, a 5% car weight reduction would lead to an increase in fuel economy of approximately 1.8% for European average vehicles, and up to 2.4% for US cars leading to a decreased CO2 emission. Further use of carbon nanomaterials for other car parts could cut this numbers even more.

Extreme conditions and high current carrying loads would appear to be ideal candidates for UltraWire, with potential weight saving of ~1.5kg per vehicle if it is applied on mild power wire. This weight equals to a decrease of 0,15g of CO2, very important for the aim of 95g of CO2 per vehicle in 2020.
The impact of weight reduction can be also significant for aircraft industry. Replacing the shielding in an aircraft with carbon nanotube materials can reduce the weight of aircraft wiring by as much as 30 to 50%, or as much as 500kg. Replacing the copper core conductor with a CNT core conductor would result in up to a 70% weight reduction for cables.
UltraWire will not only redress the balance in terms of specific conductivity but will also provide a step changes in other thermal and physical properties, such as strength and fatigue resistance.
UltraWire has the potential to sustain the long term health of the European copper industry providing both a defence to current industrial applications of copper and opportunities for new applications based on an enhanced set of electrical, thermal and physical properties.
Even with a limited production of conductors the value creation will be improved: high end applications mean a higher margin and revenue at lower conductor unit price, with benefits for both supplier and customer all along the value chain.

List of Websites:
www.ultrawire.eu
Dr Krzysztof Koziol, coordinator, telephone: +447739580339, email address: kk292@cam.ac.uk

Related information

Documents and Publications

Contact

Renata Schaeffer, (European Policy Manager)
Tel.: +44 1223 761648
Fax: +44 1223 332988
E-mail
Record Number: 195886 / Last updated on: 2017-03-10