Skip to main content

Development of Graphene based Contact Position Sensors

Periodic Reporting for period 1 - GrapheneSens (Development of Graphene based Contact Position Sensors)

Reporting period: 2017-02-01 to 2017-07-31

Contact Potentiomter sensors utilise the movement of a conductive ‘wiper’ along a resistive track to measure position relative to a change in voltage. Potentiometers are simple devices that provide absolute linear and rotary position measurements within a given range at low cost. Their main disadvantages relate to poor wear characteristics (leading to reduced sensor reliability, drift and lifetime) and limited sensor accuracy (track surface roughness leading to noise). Whilst manufacturers have sought to address these challenges through novel sensor designs using multi-layer resistive tracks (to enhance wear), such approaches do not fully address the problem whilst adding extra cost.

In the automotive industry, position sensors are now common in most mechanical systems, from seat and mirror position through to safety critical powertrain applications such as those used for accelerator pedal, gear shift, crank position. From the consumer perspective, intelligence through sensors will enable greater comfort, safety, convenience, reliability and fuel efficiency. Reduced emissions will lead to lower car/road tax. Besides the sensors being involved in the management of the engine, position sensors represent a key technology in helping OEMs to meet legislative emission targets and to avoid costly fines for OEMs .

Through GrapheneSens project we at the Precision Varionic International (PVI) are aiming to develop graphene enabled cost-efficient contact position sensors; linear Potentiometer (potentiometer + wiper) and Encoder (encoder + wiper). These sensors utilise the unique properties of graphene formulated into nano-composite coatings in achieving enhanced accuracy, lifetime and low cost. In terms of techno-economic performance, GrapheneSens product outperform the current SOA products in the following aspects:

High durability life cycle~4 million, the standard cycle is ~2.5million - Potentiometer sensor
Accuracy; 40+ pulse, the standard is 6-12 pulse, a lifetime of >100,000 cycles – Encoder sensor
28.8% cheaper with selling price of €1.26 and 22.3% cheaper with a selling price of €0.54 for the potentiometer and encoder sensors respectively.
In this study, along with development of a business plan and communication with the end user, we have performed supply channel analysis, market research, IPR management, KPI definition and associated risk analysis. We have communicated with our current customer bases and other OEMs of automotive, tire 1&2 suppliers of automotive, OEMs of joystick etc., aiming to ensure and explore the market of the GrapheneSens product at global level. We have already signed an MoU to set up a joint venture with Badve Engineering (a large manufacturing company in India with turnover over $300 million) to exploit the emerging market in Indian and the South Asian market. Recently, we have signed an MoU with Creative Lighting Solutions. Within the next few months, we expect to receive few more of the signed MoUs. In task 2, we have defined KPIs relevant to different process of manufacturing graphene based position sensors. In task 3, we have performed detailed market research which elaborates the size, growth and trend of our primary and secondary market segment. In task 4, we have performed supply channel analysis to evaluate quality graphene suppliers with whom we might sign long term contract. The graphene supplied by the Cambridge Nanosystems matches with the desired specification, hence, they might be a good option with whom we can sign long term contract for quality graphene supply.

In task 5, we have performed freedom to operate analysis and formulated IPR strategies with the support of IP expert. After reviewing patent and CORDIS databases, we have become confident that we have the freedom to operate and that there is sufficient ‘white-space’ for us to protect and exploit Graphenesense concept and technology components within the EU, US and globally. In task 6, along with SWOT analysis, we have performed risk anlysis associated to technical, commercial and environmental aspects which will assist us to proceed with the Graphenesense concept for the next stage of development.

In task 7, with the support and advice of the EC coach, we have developed a business plan incorporating the findings of the previous tasks. For the next stage development of GrapheneSens project, we were advised to perform environmental performance evaluation of our product in addition to the demonstration of techno-economic performance of the product. Environmental performance evaluation will illustrate the resource and energy consumption at product lifecycle stages. The EC coach has outlined few aspects of our product which will lead to ensure superior environmental performance compare to SOA contact sensors.
Currently, there is no contact position sensors found based on graphene. Graphene is considered to be the strongest, most impermeable and conductive material known to man. Despite offering superior tribological properties, surprisingly little research has been undertaken to combine these unique properties with graphene’s other well know properties (conductive and barrier). We have found that graphene is ideal to use in sensors due to graphene’s excellent tribological properties: its ability to provide excellent low friction and high wear properties regardless of environmental conditions (both humid and dry environments); and the formation of a barrier layer between the substrate surface and the environment thereby preventing the permeation of liquids and gases leading to unwanted reactions at the substrate surface (such as oxidation / corrosion). These successful findings demonstrated the potential for graphene inks capable of being formulated and processed to achieve both excellent conductive and resistive properties and the barrier properties. Graphene ink deposition in contact sensors will increase the durability and accuracy but lower the cost per unit, as expensive palladium, gold metal will be replaced by a small quantity (2%) of graphene as a nano composite ink.

GrapheneSens will create significant socio-economic and environmental impact: i) Increased use and reliability of ‘intelligence’ (monitoring and control) within cars will lead to improved safety, comfort and convenience as standard; ii) Reduced car emissions through greater engine stability and management will support government priorities with regards to reducing CO2 emissions and other engine pollutants; iii) Business growth within EU industry from graphene enabled materials will lead to new industry skills and jobs, including 52 directly from the GrapheneSens activities and securing many more through wider exploitation into secondary markets; iv) Considering only automotive sector at global level, on average Graphenesense product, will save €1,655.11 million per year; v) Net 42.50 kg CO2 emission and 980 litre water could be saved for using a graphene based single wiper unit instead of existing SOA wiper unit; vi) Considering only automotive sector at global level, on average Graphenesense product, will save 263,872 million tonnes of CO2 emission and 6,083,971 mega litres of water per year; vii) Considering only the automotive sector, Graphenesense product will create average annual graphene demand amounting 11,191.60 tonne.
Graphene enabled Encoder and Potentiometer