Wireless Charging for Drones

In its introduction, Global Energy Transmission Corporation (GET) promises virtually indefinite flight for multi-rotor aircraft.  “GET re-invents [the] commercial drone industry providing [a] technical solution to power drones in 24×7 mode around dedicated area[s]. An electrically powered drone can recharge and fly indefinitely via efficient safe high power in-flight rapid recharging in a GET power hotspot. The company’s distance wireless charging technologies uniquely enable drone delivery and many other industrial applications.and many other industrial applications.”  This wireless charging concept goes back a long way.

Tesla’s Dream

In the film The Prestige, key parts center on visits to Nikola Tesla’s laboratory in upstate New York, where the tower that dominates the grounds was one of his dreams.  Although never completed in real life, images of its planned form captivated readers and promised endless supplies of electrical energy to the world – with power from Niagara Falls flowing to land and sea wirelessly.

New York American, May 22, 1904: Tesla’s Tower – Amazing Scheme of the Great Inventor to Draw Millions of Volts of Electricity Through the Air From Niagara Falls and Then Feed It Out to Cities, Factories and Private Houses from the Tops of the Towers Without Wires.  Credit: The Tesla Society

Whether even the mighty Niagara could power the world (Tesla might have been forced to build additional towers at Victoria or Angel Falls, for instance), the idea of wireless transmission of energy has its adherents.  Lockheed Martin and a company called LaserMotive kept a fixed wing drone aloft for 48 hours by beaming laser-focused energy its way in 2012.  LaserMotive has recently changed its name to PowerLight Technologies, but continues its research in powering drones and other electrical devices remotely.

An Eight-Meter Diameter Open Field Charger

Today, another company offers a way to recharge aerial drones in flight.  “Global Energy Transmission Corporation (GET) Presents a new Distant Wireless Power Technology that can power industrial drones with a range of many meters from a safe, simple easy to install power transmission cord (energy transmitter).”  In fact, the company suggests that it can project energy over a mile, but apparently only if the cord is stretched that far.  “The key feature of the technology is a long length flexible transmission cord, which forms [an] area of energy reception with a distance of up to 20 meters from the transmission cord. The transmission cord can be much longer and reaching 100s of meters or even several miles!”

Awarded 3rd place in Technology innovation at the AUVSI (Association for Unmanned Vehicle Systems International) Xponential 2018 show, GET announced and revealed its systems at the event.  One can purchase a complete setup with an eight-meter diameter charging station and two very large drones as a starter set.  The drones are fairly hefty, weighing 8.2 kilograms (18 pounds) without batteries and spanning 160 centimeters (5.25 feet).

Because of their weight, each GET drone requires 1.55 kilowatts of electricity to stay aloft (at 13.6 kilograms or 29.9 pounds), giving the eight-rotor machine a hover time of 28 minutes.  That drops with increasing vehicle weight, of course, with a machine loaded to the maximum weight of 19.6 kilograms (43.12 pounds) being able to hover for only 16.2 minutes.  At a maximum cruise speed of 60 kilometers per hour (37.2 miles per hour), the fully-loaded drone can travel about 10 miles between charging stations.

hovering requires thrust equal to the weight of the multi-rotor vehicle, while a fixed wing aircraft uses only a fraction of that power to travel quickly with the same maximum weight.  This brings about the possibility of employing craft that would hover to recharge and move on in horizontal mode.  A network could then spread over a wider area with fewer charging stations.

Certainly, the principles at GET have found a way to recharge an aircraft wirelessly.  Future developments may see larger machines and even faster charging, with the possibility that long-range flights of people-sized payloads might be possible.  Tesla might be cheering this group on.

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The Second SmartFlyer Challenge 2018

Grenchen Airport in Switzerland held the second SmartFlyer Challenge on September 1st and 2nd, with a good showing for the European – and especially the Czech electric aircraft industry.  Although smaller in numbers of airplanes than last year’s premier event, the Challenge featured a series of top-drawer presentations by industry leaders, and the viewing of a new Czechoslovokian electric motorglider.

A Distinguished Visitor

Interest in the event is high in the Canton of Solothurn, the administrative region in which Grenchen resides.  The head of the Department of Economics for the Canton, Brigit Wyss, reported on the event in her personal blog.  She proclaimed, “Grenchen establishes itself as the European center of electric aviation. The Smartflyer Challenge, which was a novelty a year ago, caught the attention of the representatives of the electrical aviation industry in the second issue.  Although fewer aircraft were present than a year ago, the exchange and networking among the actors continued seamlessly.  The international character of the event is underlined by the fact that guests from Germany, France, Luxembourg, the Netherlands, Slovenia, the Czech Republic, Turkey and the USA were at the Grenchen regional airport.”

Hans Marthaler (right) explains to Councilor Brigit Wyss (left) as well as Grenchens Bürgergemeinde President Franz Schilt and his wife Trudi the electric aircraft Pipistrel Alpha.  Pipistrel had its charger on hand, probably comparable to the Czech ΦNIX unit

The Grenchner Tablat reported one reason for the smaller turnout this year.  “‘The accident of Siemens electric aircraft has noticeably unsettled and thrown back the scene.’ René Meier from the organizing committee of the second ‘Smartflyer Challenge’ in Grenchen did not mince matters to the media. At the beginning of June, a prototype of an eFusion type aircraft of the Hungarian manufacturer Magnus Aircraft crashed with propulsion technology and batteries from Siemens eAircraft on board in Hungary. The experienced pilot and a passenger were killed. It was the first accident of the still young [aircraft] scene with fatal outcome. According to Meier, there are still no findings about the cause of the accident.”

MGM Compro Makes a Good Showing

Only two Swiss products made the show on their home turf, the SmartFlyer (an entry soon on this promising hybrid) and the Archaeopteryx glider.  Pipistrel brought its Alpha Electro Trainer and a charging station.  All other aircraft on display came from the Czech Republic, with MGM Compro powering five of them.  An MGM motor also powered the Archaeopteryx.

ΦNIX – Polishing a Green Flight Challenge Competitor

One promising newcomer, premiered at this year’s Aero Expo in Friedrichshafen, seems to have a variety of ways to increase range and endurance with on-board range extenders, and ensure readily-available charging on the ground.  Pure Flight Solutions, the manufacturer of the system, promotes the “possibility of solar support, or battery storage support for maximum charging power,” with four outlets providing up to 100 kW each.  According to Pure Flight, the charger can accommodate aircraft and cars with CHAdeMO, CCS and ΦNIX connectors.

The airplane is a development of the Phoenix motorglider which participated in the 2011 Green Flight Challenge.  It was the only fully gasoline-powered machine in the contest, both the Pipistrel G4 and e-Genius being battery-powered and the Embry Riddle entry being a hybrid.  The Czech developer attempted to produce an electric Phoenix with retractable gear, but did not make it in time for the Challenge.  Jim Lee and co-pilot Jeff Shingleton flew the production version with a Rotax engine and finished with a creditable third place while garnering interest in the versatile machine.

Incidentally, the airplane’s name is a bit of a pun, Φ being the Greek letter phi.  As the manufacturer explains, “Φ – It is the Greek letter”phi.”  The name is from [the] petrol version – Phoenix and from physics – Φ is the electrical potential.”  The firm’s goal is more straightforward, though:  “Realization of alternative propulsion systems based on electrical energy with new technology like using mechanical, magnetic or aerodynamic range extenders.”

The new electric airplane looks like a modestly improved version of the seven-year-old machine, and features a Rotex electric REX 90 motor which produces 60 kilowatts (80.4 horsepower) from its 16.9 kilogram (37.18 pound) mass.  It swings a new propeller designed especially for electric power. In-flight adjustable, the 1.6 meter (5.25 feet) two-blade unit weighs only five kilograms (11 pounds).   The glass cockpit is simple, functional, and if as comfortable as the Phoenix your editor tried in 2011, desirable.

Despite the reduced participation, this year’s Challenge helps establishes Grenchen as a serious community for future flight, and MGM Compro as a firm able to supply motors in a wide range of outputs and applications.  We look forward to next year’s event, with a broader representation and some promising aircraft under development ready for their public debut.

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Print ‘Em and Stick ‘Em Solar Cells

University of Newcastle (UON) researchers may have achieved a breakthrough in creating solar cells on flexible plastic made in a roll-to-roll process with an unbelievably low price and equally incredible sensitivity.  They seem to have succeeded where an American firm failed half a decade ago.

Printed solar cells were first attempted about a decade ago, with Konarka trying to make solar cells on simple ink-jet printers.  The company failed, despite having a Nobel Prize winner and other top physicist and chemists overseeing the process.  The “cells” never achieved more than about four- or five-percent efficiency and their plastic substrate deteriorated rapidly.

Professor Dastoor with an early installation of his flexible, printed solar film

Today, The University of Newcastle in New South Wales, Australia, and CHEP, a client firm, are displaying their thin-cell, recyclable plastic solar film that can be stuck to things with double-sided tape.  Used initially to monitor response to different solar conditions, the recently-installed film shows some highly-desirable characteristics.  Professor Paul Dastoor claims, “Our printed solar solution continues to function consistently in low light and under cloud cover, which means that users don’t experience dips in productivity.”

So sensitive, the material can even produce small quantities of energy from moonlight (no efficiency numbers are given), it also costs a somewhat unbelievable $10 Australian ($7.15 USD) per square meter (10.76 square feet).  Your editor had to reread the numbers and check the calculations, but 1,000 square feet of this material would cost only about $715 USD.

In the video, one sees a connector plate that runs down the side of the building to a probable termination at an inverter.  One sees the installation on a corrugated metal roof double-sided tape.  One wonders how long the plastic substrate will last in Australia’s, or southern Florida’s sun and how soon some experimenter will tape the film to a wing and power a battery pack.

Questioned as to whether we will be able to go to a Home Depot or Lowes to get enough solar film to roll out on our roofs, Dastoor responds with a different business plan.  “In future, we expect users might sign onto this energy solution in a similar way to a mobile phone plan, where you determine your usage requirements, pay a monthly service fee, but never need to ‘own’ the infrastructure. The service provider installs and upgrades your service for you as the technology continues to develop.”

UON solar cells can be applied with little more than double-sided tape

Working with CHEP (Commonwealth Handling Equipment Pool) UON hopes to test out its technology, already doubling output from one installation to the next.  CHEP makes pallets, which we see on the ground behind their ground-breaking roof in the video, making plain why the CHEP representative compares the solar film to those load carriers.

Professor Dastoor has shepherded the process from the beginning, and sees a bright future for his brainchild.  “We have developed every aspect of the system in-house at the University of Newcastle, from the creation of the electronic inks to the printing and installation process.

“Then via experiments such as this commercial installation with CHEP we make vital tweaks to the system, which edge us ever closer to our goal of seeing this renewable energy technology on every roof.”

Or perhaps every airplane.  Eric Raymond flew across the United States in 1990 on available, not very efficient, solar cells.  These sound a great deal more powerful, and the cost will doubtless lure a great many experimenters to try them.

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Dr. Birgit Weißenbach of Elektra Solar GmbH and PC-Aero announced “The world’s strongest multifunctional solar-electric HALE aerial vehicle – the Elektra Two Solar: [with] “Take-off, flight and tough-down” successfully completed with [its] own autopilot system

Elektra Solar Two returning from its successful mission

We usually think of HALE (High Altitude Long Endurance) aircraft as being huge, sun-eclipsing things like AeroVironment’s flying wings or Boeing’s Phantom Eye.  These require large support systems and ground crews, much like the team that chased Solar Impulse around the world.

Elektra Solar GmbH, a joint venture combining PC-Aero GmbH and Elektra UAS GmbH, uses aircraft designed by Calin Gologen, head of PC-Aero, and computer technology from Dr. Ing. Habil. Konstantin Kondak.  Since October, 2009 he headed a key research area, Flying Robots at DLR’s Institute of Robotics and Mechatronics in Oberpfaffenhofen near Munich.

Their collaboration led to two svelte HALEs, the smaller Elektra One Solar (a veteran of a solar-powered Alpine crossing) and the larger Elektra Two Solar.  This airplane is also the basis for Raphael Domjan’s SolarStratos, intended to take adventurous souls to 75,000 feet, close to the Perlan’s record altitude.  Last week’s flight of the Two was a demonstration of the new redundant autopilot system, which successfully completed several autonomous flights without human intervention, even though a safety pilot was aboard.  Elektra Solar reports, “With no problems and in less than ideal weather conditions, take-offs and landings took place. During the flights various parameters and modes of the whole system were tested.”

On the ground, Elektra Solar Two shows small bubble canopy for safety pilot

Dr. Konstantin explains, “We have taken a giant step towards the stratosphere and are very optimistic that we will be able to fly in a short time with our next aircraft at altitudes up to 20 [kilometers].

“We are not yet able to achieve this goal with the current aircraft. However, in order to achieve this, we followed new paths in the manufacture of the next aircraft in process and production technology.”

The firm, located in the Bavarian city of Landsberg am Lech “manufactures manned and unmanned aircraft for scientific and commercial tasks.”  The company claims independence from suppliers, being able to make everything in-house, with 100-percent value added.  Development of control algorithms and systems receives support from “close cooperation” with the DLR Institute of Robotics and Mechatronics.

Both “aircraft are characterized by long flight times and are able to carry payloads of up to 100 kilograms.  The double-redundant, solar-electric propulsion system is powered by the sun.”  Motors are arranged on a single output shaft with one or both able to provide power at any time.  Full power is 32 kilowatts.

The craft are served by dual redundancy on the motors and triple redundancy on the control system.  This ensures systems reliability and the “robust construction of the structure… allows uncomplicated and economical operation of the systems.”  Combined with virtually noiseless operation and the “highly efficient ‘Energy-Saving-Concept’… supported by the latest state of the art extremely powerful solar cells,” the airplane should be able to meet its objectives of “day and night flight missions for a wide variety of economical applications.”

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Futurism  ponders, “Sugar, Light, And A New Type of Chemistry — What It May Take To Wean Us Off Fossil Fuels” in an article by Dan Robitzki.  The topic brings a new term into your editor’s vocabulary – BioLEC – Bioinspired Light Escalated Chemistry.  The goal of such chemistry is to use the energy of two photons, “the tiniest quantifiable units of light, to power chemical reactions.”  This takes us into how trees and other photosynthesizing plants use quantum theory to make things grow.

Trees Have Been Doing it For Years

It’s a bit odd to think of trees and quantum physics in the same sentence.  Your editor used to think of sunlight striking leaves and chemistry taking place in a leisurely way inside while the tree or bush grew.  It turns out that things take place at light speed inside the tree, with quantum activity in abundance.

Outdoing Mother Nature?

Researchers have tried to outdo Mother Nature with artificial leaves.  One of the early proponents of this approach, Daniel Nocera of Harvard claimed ,“This hybrid microbial | artificial leaf system, called the bionic leaf, operates at unprecedented solar-to-biomass (10.7%) and solar-to-liquid fuels (6.2%) yields, greatly exceeding the 1% yield of natural photosynthesis.”  He and his partner, Pamela Silver, continue to expand that potential.  Other researchers such as Nathan Lewis at CalTech, have their own programs with varying means of using enhanced photosynthesis.

To further such research, the U.S. Department of Energy set aside $100 million this year to fund 22 new Energy Frontier Research Centers (EFRC) and renew several others. One of them, a new lab at Princeton University, is slated to receive almost $11 million over four years.  Their team is attempting to power the world with plants and industrial waste.

Gregory Scholes, a Princeton chemist and the Director of the BioLEC project, thinks that we can achieve that by using BioLEC to duplicate what happens inside a leaf in the laboratory – and then control the process to gain desired outcomes.

As reported in a Princeton news item, “Under the leadership of Gregory Scholes, the William S. Tod Professor of Chemistry, the research center will seek to ‘employ light harvesting and advances in solar photochemistry to enable unprecedented photo-induced cross-coupling reactions that valorize abundant molecules.’  The center aims to revolutionize chemist’s ability to make new molecules, fuels, and materials by using the collective energy of two packets (quanta) light to break and make strong chemical bonds. A new range of chemical building blocks will be picked apart, aided by the sun’s energy, and crafted into new structures with valuable functions.”

Carbon-based substances such as sugar or alcohol, according to Futurism, “Contain a chain of carbon atoms connected to an oxygen atom and a hydrogen atom (OH).”  Apparently the bonds linking carbon atoms are hard to break.  adding an extra photon would weaken that bond.

Robitzki explains, “If we could break down those bonds, we could create jet fuel, which is another molecule mostly made up of carbons. On paper, it seems easy to get from alcohols to fuel — just link the carbons together in a certain way and discard the oxygen atoms in the form of pure water.”  Making jet fuel, however, requires the added energy of a second photon to break all the bonds.  Right now, that’s too hard for “even the  most advanced scientific tools we have.”

This Takes a Special Kind of Sharpshooter

That extra photon would have to hit a catalyst, striking it “With…  a very precise amount of energy at the exact right time to the exact right part of something that’s too small to see. There’s so much precision required, in fact, that no one has been able to figure it out.”

Starting with things abundant in nature, including light itself, and making fossil-free fuels without going through the messy and dangerous processes those involve would certainly be a blessing to the planet.  Robitzki speculates that if we can extract jet fuel from sugar cane, we should be able to use the same techniques to extract useable products from industrial waste or garbage.  He sees this as a way to drive down the cost of energy and “Get rid of the carbon emissions that come from burning these fuels once we have them.”

Scholes says, “We think our research will work because nature uses similar principles in photosynthesis.  It sort of sounds simple. ‘Oh, absorb light twice.  It’s a lot more difficult than that. We have all sorts of strategies, and that’s why it takes all sorts of people.”

Scholes and his team also have  the  Laser Electron Accelerator Facility (LEAF). Located at Brookhaven National Laboratory, one of two facilities in the country…  capable of a technique called pulse radiolysis that might just break those carbon bonds — and that new field of chemistry — wide open.”

If Big, Dumb Plants Can Do It…

Shooting  powerful, extremely short-lived bursts of electrons through the molecules being studied. LEAF observes the resulting reactions.  “These electron beams collide with and energize the molecules, which triggers chemical reactions that break and form new, powerful bonds between the atoms in that molecule.”

The BioLEC team observes the billionth-of-a-second reactions, and study the intermediate steps of that reaction.  They will somehow observe “all of the various structures and shapes that the molecules assume as they respond to the added energy, as Matthew Bird, a chemist at the Brookhaven National Lab who works at LEAF, explains to Futurism via email.”

The article concludes, “It’s a daunting task. In such early stages, it’s impossible to know whether or not Scholes and his team can accomplish all their goals in just four years. But he is optimistic that they can do it. After all, the underlying science already exists. If a whole bunch of big, dumb plants can figure out how to absorb a second photon, why can’t we?

“’It is super exciting, actually, to think about what we could achieve, and to bring colleagues and people together to do this,’  Scholes says. ‘I think what’s exciting to me is there’s gonna be some real high-impact science along the way. This is not incremental work.’”

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Solar-Only Quadrotor in Singapore

In their latest adventure in derring-do, a team from the National University of Singapore (NUS) Faculty of Engineering has developed and flown Asia’s first fully solar-powered quadcopter drone.  A large framework holds the solar cells, which are the sole means of powering the craft’s four motors.  Developers have flown the big square above 10 meters in test flights and achieved controllable flight without the use of batteries.

Frogworks Snowstorm

This is just the latest in a series of aeronautical exploits by NUS students.  In late 2015, they unveiled their Frogworks Snowstorm, a 24-rotor person carrier powered by 2.2 kilowatt (2.94 horsepower) motors driving 76-centimeter (30-inch) propellers.

Prince William, a military helicopter pilot, spent a half hour with the Frogworks team

New Asia reported that, “At the London edition of technology event Founders Forum this month, [the Frogworks team] did not imagine that Prince William would end up showing interest in it.”  His Royal Highness “spent half an hour sitting in the machine, trying out the controls and talking to the team, according to a post on NUS’ website on Friday (June 17, 2016).”

Frogworks, by the way, is “a design and prototyping studio for green vehicles founded by and for NUS students in the Design-Centric Program (DCP) at the NUS Faculty of Engineering.”

Frogworks Delta Trike

Not willing to simply levitate indoors, an eight-member Frogworks team created the world’s lightest electrically-powered hang-glider trike.  Two eight-kilowatt (10.7 horsepower) motors drive pusher propellers.  Made of carbon fiber and aluminum, Delta weighs 49 kilograms (107.8 pounds empty.  It can manage a 75-kilogram (165-pound) pilot.  NUS claims it is “the lightest aircraft in the world that can take off and land with wheels while carrying an adult pilot.”

Their Latest – A Solar-Powered Quadrotor

Most solar-powered aircraft use a battery as a backup power source or to provide sufficient energy to get the vehicle aloft at all.  NUS managed to be the first in Asia A team from the National University of Singapore (NUS) has made their quadcopter drone fly on natural sunlight alone.

The big square had flown as high as 10 meters, topping a typical three-story building.  Using lightweight carbon fiber material, the team made a frame and a bed for the machine’s 148 individually-characterized silicon solar cells.  The whole thing weighs 2.6 kilograms (5.72 pounds) and has a surface area of about four square meters (a little over 43 square feet).  The 0.13 pounds per square foot is probably necessary to enable the for

NUS sees their accomplishment as a major aviation feat because “Rotary winged aircraft are significantly less efficient at generating lift compared to their fixed wing counterparts.”  Having to lift its own weight throughout 100 percent of its flight regime requires extremely light weight or significant power – or both.  NUS has been attempting pure solar flight for the last six years, with a 2012 design gaining only 45 percent of its required flight energy from solar cells and the rest from batteries.

Associate Professor Aaron Danner from the Department of Electrical and Computer Engineering at NUS Faculty of Engineering, who supervised the project, explained “Our aircraft is extremely lightweight for its size, and it can fly as long as there is sunlight, even for hours.”  He noted the drone’s ability to land on any flat surface and fly out of ground effect.  The drone can be controlled remotely, or programmed to fly autonomously using an on-board GPS system.

In a belt-and-suspenders expansion of the machine’s capabilities, “The aircraft can potentially be used as a ‘flying solar panel’ to provide emergency solar power to disaster areas, as well as for photography, small package delivery, surveillance and inspection. Batteries can be incorporated to power the aircraft when there is no sunlight or for charging to take place during flight to enable operation when it is cloudy or dark. Other hardware such as cameras can also be included for specific applications.”

Obviously, these added capabilities make the solar-powered machine just another quadrotor with solar assistance, but the accomplishment is still noteworthy.

Frogworks team with NUS solar-powered quadrotor

One of the engineering students on the program, Yeo Jun Han said, “We encountered many engineering challenges when building the drone. These included finding an optimal number of solar cells efficient and light enough to power the propulsion system, which in turn has to be light and at the same time able to produce sufficient thrust to lift the aircraft. Other issues we faced included tuning and calibration of flight controls to enhance flight stability, as well as designing a frame that is lightweight yet sufficiently rigid. This has been an excellent learning opportunity for us.”

One supervisor from the IDP program, Brian Shohei, added, “To be able to make something fly under control for a long time is a very complex engineering problem. Our students have attained flight in its purest form, powered by natural sunlight. This is an amazing achievement.”

With commercialization in mind, the team continues to further improve its efficiency.  Opportunities for solar cell and other material development are truly only beginning.

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Battery breakthrough: Doubling performance with lithium metal that doesn’t catch fire

Longer-lasting drop-in replacements for lithium ion could be on the horizon

These two headlines top a report by Angela Wegrecki from the University of Michigan’s News Service, and despite their hopeful vibes, may even elicit yawns.  We see similar claims regularly, accompanied by promises of a five-year wait for the production models to begin rolling off the line.

Most batteries are developed by researchers working with small budgets and small facilities.  Thomas Edison had 40 assistants working with him to test the 1,600 different filaments tried before hitting on a carbonized sewing thread that gave the light he was seeking.  The University of Michigan has 2,700 square feet and probably numerous different researchers who want to use that space for different efforts.   In that space not much larger than an average American home, scientists are extracting promising results.

When the new lab was commissioned in 2015, it was already “booked solid into 2017.”

Speaking with the UM News Service, Dr. Greg Less, director of the lab, says that current research in the field is hampered by a lack of large-scale laboratory space. By providing such a space, researchers at the Battery Lab will be able to collect more in-depth and accurate data. And that, says Less, could lead to a breakthrough in battery power,

Lab director Dr. Greg Less, says, “We’re giving people the ability to make batteries better and faster than they would be able to do otherwise. That’s really the key. It would be really awesome if some company were to develop a next-generation battery, and we come to find out their initial work was done here at the Battery Lab. That would be a dream come true.”

Recently, lucky researchers granted space and time in the laboratory announced “a rechargeable battery technology that could double the output of today’s lithium ion cells – drastically extending electric vehicle ranges and time between cell phone charges—without taking up any added space.”

Their research into solid-state electrolytes has resulted in a “roadmap to what could be the next generation of rechargeable batteries.”  Jeff Sakamoto, a U-M associate professor who leads the work, claims, “This could be a game-changer—a paradigm shift in how a battery operates.”

Nathan Taylor, a post-doctoral fellow in mechanical engineering, inspects a piece of lithium metal in the Phoenix Memorial Laboratory building. Image credit: Evan Dougherty, Michigan Engineering

Sakamoto specializes in mechanical engineering of atomic-scale vacancies in advanced solid-state batteries and biomedical technologies.  He explains, “While the connection between these seemingly disparate fields may not be obvious, they do share one aspect; nothing, or, more specifically, studying the absence of mass in solids.

The University adds, “The Sakamoto group’s recent work demonstrates the deliberate and controlled creation of Li-ion vacancies (absence of mass), in garnet-based crystal structures, is key in transforming a good ionic conductor into a super-ionic conductor. This class of ceramic material conducts Li-ions as fast as state-of-the-art liquid Li-ion electrolyte membranes, perhaps enabling advanced solid-state batteries.”

Since their introduction in 1980s, rechargeable lithium batteries with liquid electrolyte have powered everything from iPhones to Teslas.  They have a downside, though, sometimes bursting into flames when dendrites form inside, short the battery and ignite the electrolyte.

To keep dendrites from forming U-M engineers stabilized the lithium metal surface of the electrodes with a ceramic layer, which also prevents degradation of the metal over time.

Sakamoto explains, “What we’ve come up with is a different approach—physically stabilizing the lithium metal surface with a ceramic.  It’s not combustible. We make it at over 1,800 degrees Fahrenheit in air. And there’s no liquid, which is what typically fuels the battery fires you see.  You get rid of that fuel, you get rid of the combustion.”

A demonstration of a machine that uses heat to densify a ceramic known as LLZO at 1,225 degrees Celsius. Image credit: Evan Dougherty, Michigan Engineering

Early tests showed lithium metal growing through the ceramic electrolyte at low charging rates.  This caused short circuits, much like those in liquid cells.  Researchers chemically and mechanically gave a “pristine surface” that enabled even plating, suppressing dendrite formation and enabling “a dramatic improvement in charging rates,” according to Sakamoto.  “With this breakthrough, we demonstrated we can charge the battery in 3 hours or less.”

Nathan Taylor, a U-M post-doctoral fellow in mechanical engineering, observed no visible degradation.   “We did the same test for 22 days.  The battery was just the same at the start as it was at the end. We didn’t see any degradation. We aren’t aware of any other bulk solid state electrolyte performing this well for this long.”

Researchers think bulk solid-state electrolytes can allow drop-in replacements for current lithium ion batteries and use existing manufacturing facilities.  Having verified their materials’ performance, the group is making thin solid electrolyte layers to meet solid-state capacity requirements.

The group’s findings are published in the August 31 issue of the Journal of Power Sources.

The research is funded by the Advanced Research Project Agency-Energy and the Department of Energy.

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George E. Bye. CEO and founder of Bye Aerospace, is on a roll these days, selling a large number of SunFlyer 2 training aircraft, delivering Silent Falcon solar electric unmanned aerial vehicles (UAVs), partnering in the TriFan 600 project with XTI Aircraft, and overseeing the first flight of the StratoAirNet prototype.

Already a mile high in Colorado skies, StratoAirNet launches on its first flight

A letter from Diane Simard, Senior Vice President of Bye Aerospace, Inc., reports “the successful completion of the first flight of the solar electric technology demonstrator prototype for its “StratoAirNet” and “Solesa” families of medium-altitude aircraft systems.”  Flying from the Northern Colorado Regional Airport, north of Loveland, the sailplane-based optionally-piloted vehicle has made additional flights since its maiden outing.

Bye expressed happiness at the event and gave thanks to those who made it possible.  “It was a great day for solar-electric aviation.  My thanks to our entire team for their persistence and extra efforts to achieve this milestone. I would also like to thank the professionals at Northern Colorado Regional Airport for their cooperation in making these flights possible.”  He also credits Greg Cole of Windward Performance, noting “We are grateful for his help with the developmental prototype!”

SolAero solar cells gleam in the sunlight over the runway

Two forms of this long-endurance flight approach are on the horizon.  Both systems will provide support for extended “…endurance commercial and government security requirements, including patrol, observation, utility, mapping, precision agriculture, search and rescue and surveillance missions,” according to the company.

The Solesa aircraft system will be piloted, performing patrol and survey missions for shorter flight durations. It will find use as an R&D test platform for new customer payloads. StratoAirNet will fly longer-endurance UAV missions following required steps before going on to even longer and more arduous tasks or carrying newly installed systems.

Bye Aerospace explains, “Both StratoAirNet and Solesa offer unique advantages over traditional systems, including lower unit cost, lower heat and noise signatures, lower operating costs and enhanced utility. Bye Aerospace is collaborating with SolAero Technologies Corp, integrating their advanced high-efficiency solar cell technologies on the advanced graphite composite wing.”

Silent Falcon also uses SolAero solar cells

SolAero’s solar cells, both four-junction and triple-junction designs, can operate at up to 32-percent efficiency and produce up to 150 Watts per kilogram.  Terrestrial models can achieve up to 39-percent efficiency.

About Bye Aerospace, Inc.

Bye is a busy company, as noted above.  Their web site includes this description: “Bye Aerospace is developing the “Sun Flyer” family of all-electric aircraft in addition to a family of advanced, high-altitude, long-endurance solar-electric aircraft called ‘StratoAirNet’ and ‘Solesa.’  The company was named the 2018 Small Business of the Year in the “small business” category by the Denver Business Journal. For more information, go to www.ByeAerospace.com.”

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Liquid Batteries for Aircraft?

NASA is investigating “the integration of nanoelectrofuel (NEF) flow batteries with rim-driven electric motors to produce a safe, clean and quiet propulsion system for aircraft,” according to Aviation Week.

That is the promise of an early-stage rechargeable liquid battery technology under investigation by NASA. The agency is researching the integration of NEF flow batteries with rim-driven electric motors to produce a safe, clean and quiet propulsion system for aircraft.  The rim-driven motors are used on boats as thrusters, and may have applications on small unmanned aircraft, although researchers have seen disappointing results so far.

Tying these motors to more promising research into” non-explosive energy storage technology” is part of NASA Armstrong Flight Research Center’s Aqueous Quick-Charging Battery Integration for Flight Research (Aquifer) project, along with NASA Glenn Research Center’s co-principal investigation.  A spin-off of research at Argonne National Laboratory and Illinois Institute of Technology, Influit Energy has “developed a novel type of rechargeable battery that features active energy-storing materials in pumpable liquid form, which essentially allows us to use batteries in the same fashion as gasoline-powered engines.”

A TED Talk by Influit Founder & CEO John Katsoudas shows the design philosophy behind their battery and the direction planned for the technology.  Co-founders Elena Timofeeva, Chief Operations Officer and Director of R&D; and Carlo Segre, Chief Technology Officer, round out Influit’s leadership.

Influit claims their nan0electrofuel (NEF) flow battery can achieve one-and-one-half times the energy density of lithium-ion batteries at one-half the cost.  A primary feature, “rapid charge refueling for EVs, “batteries that can conform to different shapes, and power decoupled from energy storage, make this type of battery a versatile possibility for even aircraft use.  Recharging can be done by pumping new liquids into the two storage tanks, removing the Influit vehicle from the grid.  It also enables recharging the grid or home energy storage from the vehicle, a useful potential use for load balancing or grid or in-home emergencies.

Influit says their battery enables 60-percent of the cell to be active materials.  Most conventional batteries allow only about 35-percent of the cell to be active materials, the rest taken by casing, binders, separators, and other components.  MEET (Münster Electrochemical Energy Technology,  MEET Battery Research Center, Institute of Physical Chemistry, University of Muenster, Germany) breaks this down to 49.71-percent active materials and 50.29 inactive for typical canister-type lithium batteries.  That varies for pouch and prismatic types.

Influit’s NEF battery with a comparison of active mass between it and conventional lithium batteries

The NEF battery uses positively- and negatively-charged fluids, which are pumped through a flowcell inside the larger cell.  The fluids are water-based, but infused with suspended “nanoparticles of battery-active materials” making an electrolyte that can be charged and discharged multiple times.

NASA electrical engineer Kurt Papathakis, active on the X-57 Maxwell distributed thrust aircraft, presented the Aquifer project at the American Institute of Aeronautics and Astronautics Aviation 2018 conference in Atlanta in June.  He discussed a technology roadmap that foresees NEF reaching more than twice the pack-level energy density of the lithium-ion.  Prototype NEF flowcells produce only “a few milliamps (mA) per square centimeter.  With funding, NASA hopes to deliver first-generation NEF technology with a current density of 100 mA/cm2 by 2020.  This could produce a system-level specific energy of 125 Watt-hours per kilogram or 350 Watt-hour per liter – outperforming lithium-ion.

Schematic diagram showing a flow battery with LCO/C nanoelectrofuels as one of potential chemistries to meet an EV metric of 100 kWh energy storage at 400V power.  From Influit founder’s 2014 presentation at  TechConnect World NSTI Innovation Conference and Expo

Papathakis envisions, though industry cost-sharing, 200 mA/cm2, or 530 Wh/kg, compared with 325 Wh/kg projected for lithium-ion in the same time frame.  This could go as high as 750 Wh/kg by 2023, which would seem to lead projected li-ion capacities.  Fluids can be pumped through the flowcell multiple times until the active materials are discharged.  (There is no explanation of whether these fluids are less energy dense following each cycle.)  Wind and solar energy can recharge the spent fuel, eliminating greenhouse gas emissions from the life cycle.

Papathakis says, “We have demonstrated multiple recharge cycles and seen minimum to zero degradation.  Also, unlike Li-ion batteries, NEF does not pay a penalty in cycle life for charging above 80-percent capacity or discharging below 20 percent.

Interestingly, Influit includes a quotation from Mike Bowlin, Chairman and CEO of ARCO (now BP).  “We’ve embarked on the beginning of the last days of the Age Of Oil.  Embrace the future and recognize the growing demand for a wide range of fuels or ignore reality and slowly—but surely—be left behind.”  Maybe he’s on to something.

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Erik Lindbergh, grandson of the famed trans-Atlantic flight pioneer, has been paying his dues in aviation for decades, working to involve young people in career-building roles, and advocating for “green” aviation.  His latest roles have found him mentoring a group of Embry Riddle students in developing an electric HK-36 (shown last year at AirVenture), and in developing one of the over 100 electric vertical takeoff and landing (eVTOL) potential sky taxis coming into public view.  That sky taxi may not make it to market, but Lindbergh and partners’ Integrated Distributed Power system is headed that way.

At the 2017 AirVenture, he shared the news that he was working on something exciting.  That turned out to be the VerdeGo project, an eight-rotor eVTOL which he developed with co-founder Eric Bartsch and Embry Riddle Director of the Eagle Flight Research Center and Green Flight Challenge competitor Dr. Pat Anderson.  Eric is Chief Operating Officer for VerdeGo and Pat is Chief Technology Officer.

Their first product, the PAT200 Personal Air Taxi, is apparently on hold, according to eVTOL News, but the power system is being developed as a basis for other air taxis.  There should be a market among the other 100 developers for power systems that can elevate their Ubers.

Model of VerdeGo’s PAT 200 at this year’s AirVenture Innovation Center

Aviation Week states the new business plan a bit more dramatically.  ” Seeing a dire need for propulsion expertise in the burgeoning electric vertical-takeoff-and-landing (eVTOL) market, one of the contenders has decided to put aside work on its vehicle and focus instead on providing hybrid-electric systems to other developers.”

Under development at the MicaPlex Aerospace Innovation Complex in the Embry-Riddle Research Park in Daytona, Florida, the Integrated Distributed Electric Propulsion (IDEP) system is “Balanced to optimize performing many functions for the aircraft.

Schematic for PAT 200 shows elements of VerdeGo’s combined power and control system

System elements include engines, generators with one to two inputs, a power distribution system, batteries and battery management systems (BMS), attitude control, motors, rotors, and some form of noise mitigation system, essential for urban acceptance.

IDEP components in first-generation system

Approaches, according to VerdeGo, include “optimized multi-rotor arrays and low-noise generator installations.”  As opposed to “traditional propulsion, designed only for producing thrust,” IDEP provides “Propulsion Integral to All Aspects of Performance,” with a system architecture that has built-in redundancy.  Because rotors span the entire airframe, they enable distributed thrust and attitude control.  Rotors and motors act as an integrated pair.

In the traditional approach, propulsion units simply deliver thrust, relying on the airframe architecture design to create redundancy and attitude control.  IDEP provides both propulsion and control, with built-in redundancy (eight rotors) and attendant safety.  VerdeGo claims “today’s technologies… enable Urban Air Mobility to start NOW,” and add that the four-to-eight-rotor system will be, “Ready for UAM commercial launch in 2023.”

First up, the IDEP-H2 system is “optimized for 2-3 seat aircraft,” with 200 to 325 horsepower input power from a piston generator.  A second system, the IDEP-H2-Twin, also for 2-3 seat aircraft would have 280-horsepower input power, but using twin generators for “added redundancy.”  Future plans call for an IDEP H7, designed for five-to-seven seat aircraft and running on 500 to 800 total horsepower from a turbine generator.

Longer-term programs, “Ready when high-performing batteries are available,” will combine battery power with other elements of the IDEP drivetrain.  VerdeGo estimates these systems will be available from 2030 to 2040 depending on quickly the battery industry can meet VerdeGo’s requirements.

Pat Anderson provides his own, somewhat indeterminate, estimate of when that will take place.  “Everyone has their crystal ball for the timing of new battery technologies.  We have been working for more than a decade with the global battery experts who project it will be 15 to 20 years before commercial levels of performance are achieved from a purely battery-operated VTOL aircraft.  VerdeGo’s first-generation IDEP hybrid systems enable aircraft manufacturers to get into the air with technologies available today, with an upgrade path as soon as batteries are available.”

In the meantime VerdeGo is crafting an “iron bird,” ground-bound test vehicle for the PAT200, which will now be used as a testbed for the IDEP systems.  Lindbergh adds, “We are doing all the steps as we would have before, but now we have opened up our propulsion system to all the competition.”

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