Sourced from http://www.masdar.ae/
I’m not sure if you’ve been watching the adventures of, or better yet, the great strides being made by Solar Impulse 2 – the aircraft that is powered only by the sun. On July 3, 2015, the Solar Impulse 2 landed in Hawaii after making a historic five-day trans-Pacific crossing. This ended a 7,200 km flight from Japan, the longest leg of its round-the-world flight. Solar Impulse 2 incorporates a host of innovative solutions into its design, thanks to rare metals, that make it lighter and allow it to consume far less energy than a traditional airplane.
Solar Impulse 2 began its epic journey on March 9 departing from Abu Dhabi, where it will eventually return. Over the course of its mission, Solar Impulse 2 will fly for nearly 500 hours, cover 19,000 nautical miles and cross two oceans and four continents. The highly efficient solar panels and lightweight lithium batteries developed specifically for this demonstration were key to its success.
The Solar Impulse project is supported by several global technology companies, including ABB Inc. ABB Inc. is a European-headquartered entity that touts its record in power and automation technologies that enable utility, industry and transport companies to improve their performance while lowering environmental impact.
The Solar Impulse 2 aircraft, a larger version of a single-seat prototype that first flew five years ago, has a wingspan of about 235 feet – larger than that of the Boeing 747. Built into the wings are 17,248 ultra-efficient solar cells that transfer solar energy to four electrical motors that power the plane’s propellers. The solar cells also recharge four lithium batteries that power the plane at night.
The solar cells were provided by SunPower Corp., a Silicon Valley manufacturer of high-efficiency solar cells, solar panels and solar systems. SunPower’s Maxeon solar-cell technology claims solar cell thickness of an average of only 135 microns, which is important for the power-to-weight ratio of the aircraft. The solar panels are also claimed to be 22.7% effective (in comparison, the efficiency of solar panels used on homes is 16%). The highest performing solar panels are those used on satellites (30%), but they were deemed too heavy for the solar aircraft.
Thanks to the weight, efficiency and lifespan ratio, the Solar Impulse can use lithium-polymer batteries, produced using an innovative chemical formula that has improved the oxidizing process. International chemistry group Solvay engaged its R&D resources to improve the energy density in order to reach 260Wh/kg. It has since commercialized this technology (PVDF binder, fluorinated polymer) for the automotive industry, as well for the portable electronics.
As for the aircraft itself, a couple of other interesting stats:
The wingspan is 71.9m (236 ft), slightly less than that of an Airbus A380, one of the world’s largest passenger airliners.
17,248 photovoltaic cells cover the top of the wings, fuselage and tail for a total area of 269.5 m2 (rated at 66 kW peak).
Unlike the 500-ton A380, the carbon-fibre Solar Impulse weighs only 2.3 tonnes (5,100 lb), a bit more than an average automobile.
The aircraft is equipped with 4 × 17.4 HP electric motors powered from solar cells and 4 x 41 kWh lithium-ion batteries (633 kg), providing 13 kW.
It contains advanced avionics, including an autopilot to allow for multi-day transcontinental and trans-oceanic flight.
Supplemental oxygen and various other environmental support systems allow the pilot to cruise up to an altitude of 12,000 metres (39,000 ft).
Propeller diameter:1 ft
Maximum speed: 87 mph
The Solar Impulse 2 was first publicly displayed on April 9, 2014.
If you would like to learn more, just click on http://mauitvnews.com/blog/2015/07/03/solar-impulse-2-makes-first-u-s-stop-in-hawaii/ or http://www.theengineer.co.uk/in-depth/your-questions-answered-solar-powered-flight/1018793.article
Some folks argue that technological advances such as this can have a direct impact on efforts to reduce fossil fuel use in the electricity sector. I would support that premise, fully respecting of course that the Solar Impulse initiative incorporated very carefully engineered materials. But there will be spin offs.
This is also another excellent example of focus on efficient and sustainable technologies, enabled by the application of rare metals, other critical materials with a dabs or two of chemistry and materials science
Rare Metals Matter…
Until soon… Ian
Source: http://raremetalsmatter.com/solar-power-lithium-batteries-carbon-fibre-impulse/