Storedot: Silicon and Tin for a Fast Charge

Storedot is an Israeli battery company with an appealing sales pitch – their batteries can be fully charged in minutes rather than hours.  To make that happen, they are combining silicon, long considered a necessity for high energy density, and a more humble material – tin.

Silicon, tin and other nanoparticles are one factor enabling Storedot’s fast-charging capabilities

Beside the unique material blend, Storedot is working on a 4680 battery (46 millimeters in diameter, 80 in length) equivalent to what Tesla has announced for use in its cars.  Storedot claims 10 minutes for a full charge on an automobile.  They demonstrated the ability to fully charge an electric scooter in five minutes last year.  Autos could have 200 miles added to their batteries in 10 minutes by 2024, based on Storedot’s timeline.

Storedot differentiates between range anxiety, the nervousness caused by wondering if your EV will make it to the next charging station, and charging anxiety, the worry that a charger will not be available when you arrive.  Another anxiety in today’s world is what to do while the car charges – sometimes a seven-course-meal pause – usually in areas where such repasts are not the norm – but guys named Norm are.

Doron Myersdorf, CEO of StoreDot, reflects on the problem.  “The number one barrier to the adoption of electric vehicles is no longer cost, it is range anxiety.  You’re either afraid that you’re going to get stuck on the highway or you’re going to need to sit in a charging station for two hours. But if the experience of the driver is exactly like fueling [a gasoline powered car], this whole anxiety goes away. A five-minute charging lithium-ion battery was considered to be impossible,” he said. “But we are not releasing a lab prototype, we are releasing engineering samples from a mass production line. This demonstrates it is feasible and it’s commercially ready.”

Holding things together, Storedot’s 3D binder restrains silicon swelling during lithiation, necessary because of speed of charging.  The company even claims that their binder enables “self-healing” during expansion and contraction of nanoparticles

To enhance stops at charging stations, Storedot has patented a “boost” program that optimizes a charging station’s ability to keep up with the high-powered batteries’ demands.  “Late last month, StoreDot filed a patent for technology that creates a “booster” feature that allows the battery to analyze the capability of the charging station in real-time and adjust the battery’s ability to carry high current rates. These systems are meant to significantly improve the rate of miles per minute of charging, the company said.”

Finances, Battery Structure, and Chinese Competition

An Australian gentleman styling himself as the Electric Viking discusses the finances necessary to get Storedot’s next best thing in production.  He is dubious that this will be an affordable option for the vast majority.  Instead, he notes this will be high-end technology not unlike the original Tesla car, with the tech finding its way into a broader, less expensive market over time.  Storedot’s choice of relatively inexpensive materials and their insistence that commonly available production lines are all that’s necessary for large-scale commercialization would tend to counter that outlook.

The Viking discusses potential competition from GAC, a Chinese firm with equally profound fast-charging claims and extreme mileage aspirations.  One must remember that another Israeli firm, Phinergy, is also in the fray with new backing from Indian Oil Corporation.  They use an aluminum-water oxidation process to generate electricity for 1,000 kilometer drives.

Better and Better

According to the Times of Israel, “The 4680 format battery will be ready for production at scale in 2024, the company said, as will its first-generation fast-charging pouch cell, also aimed at the EV market. StoreDot is also working on extreme energy density (XED) solid-state technologies, that will allow for longer battery operability and will enter mass production in 2028.”

Storedot’s future plans lead to solid-state 25-miles-per-minute charging rates

A great deal like Tesla, Storedot is going open source, making its production capabilities (but not necessarily its proprietary chemistry) an open book for use by auto makers and other battery firms.  Such tactics have not hurt Tesla’s market standings.

Into an Extreme Future

Storedot is now in Gen 1 development with metalloid compound A-based cells.  Verifying the technology will accompany building manufacturing partnerships and establishing supply chains.

Drone about to land on a fast charging station

Gen 2, set for 2024, will lead to silicon-based extreme fast charging (XFC), with the ability to add 20 miles range for every minute of charging.  By 2028, Gen 3 solid-state-based Extreme Energy Density (XED), will add 25 miles for every minute of charging.

Financial support from strategic investors including BP, Daimler, Samsung Ventures, and TDK will help ensure further exploration of speedier, more energy-dense charging.  Storedot’s willingness to share their technology will benefit the entire industry.

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Wright’s 2 Megawatt Motor

Jeffrey Engler of Wright Electric has huge ambitions, including producing a 186-seat electric airliner and now testing a two megawatt “aviation-grade motor for transport-category zero-emissions aircraft.”  If Engler’s vision becomes reality, “By 2040, Wright will eliminate carbon emissions from all flights under 800 miles.”

Wright’s proposed 186-seat, single-aisle airliner could support 45 percent of all commercial air routes, those 800 miles or shorter

Leap-frogging most other developer’s plans to make 10-, 19-, or even 50-passenger airliners, Wright plans a 186-seat, single-aisle airliner with distributed electric propulsion (DEP), spreading thrust across the wings and tail of the proposed craft

Each motor will produce two megawatts (2,700 horsepower), greater than anything now flying.  When your editor first started writing about this new technology, even model aircraft builders were ganging several small electric motors to produce enough thrust for “3D”-style flight, demonstrating the ability to hover on a propeller in aerobatics.  In 1978, Fred To used four Bosch motors and a single propeller to power his Solar One machine.

In a current perspective, the 2MW is equivalent to 66.66 Aerolite 103 motors, or 34.7 Pipistrel E-811s as installed on Velis’.  Those haul one or two people skyward, respectively on 30 kilowatts (40.2 hp) and 57.6 kW (77 hp) peak outputs.  Ten or so Wright powerplants will levitate 186 passengers with 27,000 combined horsepower.  That would provide over 107 kW (145 hp) per person, exceeding the per-passenger oomph pulling an experimental RV-10 around.

Wright’s motor next to a Coke can for reference.  2,700 horsepower from a package this size is a revolutionary change in how we will power future airliners

Noting that Wright has built this 2 MW motor “alongside contracts from NASA, the US Department of Energy, and US Air Force, and the US Army,” the firm explains it has already tested a complementary high-efficiency inverter.  Wright claims the 2 MW motor is a 2X improvement over megawatt scale motors now being demonstrated and is “designed to be scalable from 500 kW to 4 MW systems.”  According to Wright, “This allows application of the motor up to the single-aisle class aircraft to enable electric and hybrid-electric flight with little to no emissions.”  The 10-motor craft would have power equal to an A320 Airbus.

Beyond that two Wright powerplants could power a 50-seat craft such as an ATR-42 or Dash 8.  The light weight of the power system would be a boon to airlines, enabling such craft to carry “10 more passengers per flight than a plane using other industry motors.”

The motor features 10 kW/kg specific power, a two times improvement over available aircraft motors.  Coupled with a high-performance thermal system, higher voltage operation and an insulation system capable of handling those high voltages, these factors will ostensibly lead to highly-improved performance.

Adding Wright’s high performance inverter (tested separately until now) will allows Wright “to operate at high frequency with low loss.”  Wright’s inverter “uses a novel switching technology which reduces total losses by a factor of two over similarly rated systems.”  Rated at 2 MW with a 300 kilohertz frequency output, the inverter can managed 1,000 Volts.  Equally important in airframe applications, the 20 kW/liter volume equates to a compact inverter.

Integrating the motor and inverter with a suitable battery package, the system will be tested in a high-altitude chamber as part of the drive toward actual flight testing.

According to Jeff Engler, “Experts at NASA, the US Department of Energy, the US Army, and the US Air Force have aided this effort through technical guidance, funding, and standards and regulations support. Organizations like these are leading pioneering efforts to reduce the carbon footprint of aerospace, and we are thrilled to work with them.”  Additional support comes from Swiss airline easyJet and Mexican airline VivaAerobus.   With backing like that and the vision to move forward, Wright Electric might just be onto something.

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Aerolite 103 – As Simple As Aerial EVs Get

Shown and flown at this year’s Sun ‘n Fun and AirVenture, the Aerolite 103 is a well-tested, best-selling ultralight that in FAA Part 103 form is a true ultralight.  As an electric aircraft, it’s heavier and faster than accepted ultralight standards but no less a competent flyer registered in the Experimental category.

Designed in 1996, and with hundreds of the original two-stroke engine-powered versions flying, Aerolite’s originator Terry Raber sold the rights to Dennis Carley in 2012.  Manufacturing moved from Millersburg, Ohio to Delano, Florida.

The airplane retains its position as an inexpensive FAA Part 103-compliant ultralight – true to its name.  In the last few years, it has also become part of zero-emission flight.

Aerolite as an EV

One can only wonder where Gabriel DeVault finds the time.  Currently working in Hollister, California and Cirencester, England on ZeroAvia’s hydrogen-fueled aircraft, Gabriel was also powerplant developer for Zero Motorcycles.  His motors now power several homebuilt aircraft, including his personal eGull (recently sold) and his Sonex eXenos.  Since thousands of Zero bikes are on the road, a large number of “donor-cycles” are available.  Zero Motorcycles won’t talk to you if you mention the word, “airplane,” though.  So, search the used market.

Aerolite’s motor and battery packs

Gabriel designed the motor found on the Aerolite, too, creating a compact outrunner (the rotor spinning on the outside and firmly attached to the propeller).  It puts out about 22 kilowatts (30 horsepower), but likes to produce around 10 to 12 kW for a cruising speed in the mid-forties.  That makes the batteries keep the Aerolite airborne longer, too.

The 103 can carry two, three, or four 36-pound battery packs.  You need a minimum of two for flight, and that gives around 30 minutes of flight time.  Add a third for 45 minutes and a fourth for 60.  A tidy rack under the motor allows easy mounting of the packs.

Aerolite explains, “Our flight testing so far has shown that if you do a full power take off, climb to 700 feet or so, and reduce power to have a cruise speed of 40-45 MPH, you will be able to fly a maximum of approximately 60 minutes with 4 batteries.  If you want to increase your cruise speed to 60 MPH, total flight duration diminishes accordingly.  If you intend to do repetitive take offs and landings in the pattern, total available flight time will also lessen, as the consumption of battery power is disproportionately higher during full power climb (although you do not need full power to climb).”  That’s demonstrated in the Oshkosh video, with owner/pilot Greg in command.

Packs contain 240 Samsung 30Q cells, 20 each in series to obtain 72 Volts and “12 series strings in parallel to achieve the desired capacity.”  Managed by a custom battery management system (BMS) with over- and under-voltage and temperature limits, each pack is “potted,” or encapsulated in a weatherproof poly-urea compound.  They should withstand 500 charge-discharge cycles, giving one flight per day for over a year and a half.  (And seriously, the average light aircraft in the U. S. flies 80 hours per year.)

Gabriel’s 72-Volt motor weighs 30 pounds and “offers ~ 20 kW continuous and up to 25 kW peak power.”  Its low voltage enables it to produce maximum thrust at only 2,000 rpm.  Each battery weighs just under 36 pounds.  A setup with two battery packs and the motor adds 101 pounds to the Aerolite’s airframe.  With three batteries, the complete power system weighs 137 pounds and with four, 173 pounds.

Like the BMS, the motor controller provides over- and under-voltage protection and provides thermal limits for the motor and controller.  It can be connected to a display or an “app” to view EFIS (Electronic Flight Instrument System) information.

Incidentally, the electric power system can be installed on any Aerolite 103.

Gabriel’s Other “Ultralights”

In Europe, all of Gabriel’s E planes, even the “heavy” ultralight, would be classified in the ultralight category.  Clean design is important.  Even though the Aerolite 103 is the lightest, it’s also the draggiest, and used more kW than the eGull, 12 kW to eight or nine for the eGull’s faster cruise.  That’s an important factor for endurance and range and what has held fixed-wing electric aircraft back so far.  The usual complaint is that we need better batteries – some of which are near and promising.  We could see a real expansion of light electric aircraft as that promise comes to fruition.

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Xpeng X1 and X2 Fly in China

A new player in the electric aviation market, Xpeng has introduced a series of electric aircraft, and is currently test flying them.  A relative newcomer to the electric vehicle scene, Xpeng is making inroads with a sport utility vehicle (SUV), its P7 sedan, and its aerial projects.

“Xpeng or Xiaopeng Motors, also known as XMotors.ai, is a Chinese electric vehicle manufacturer. The company is headquartered in Guangzhou, with offices in Mountain View, California in the US and is publicly traded on the New York Stock Exchange,” as reported by Wikipedia.  Prices in China range from around $23,300 for the G3 to around $50,000 for the P7, claimed to have a range of up to 408 miles.  Both are slated to be competitive with comparable Tesla models.  The company doesn’t seem to be listing prices for their aerial EVs, though.

The X1 Single Seat Multirotor

Neatly covering any rotor noise with Justin Timberlake, Carey Mulligan, and Stark Sands, Xpeng demonstrates a short hop with a tidy single-seat multirotor not unlike Lift’s Hexa.

eVTOL News reports, “The aircraft has a maximum speed of 72 km/h (45 mph) and a range of 30 km (18.5 miles) or 30 minutes, whichever comes first. The original name of the aircraft was the Kiwigogo T-One (was also written as T-1 and A-1) but as of September 2020, the aircraft’s name has been shortened to Kiwigogo. (And since renamed the X1, apparently) The first flight for the aircraft was June 2018.”

The same source provides these specifications:

  • “Aircraft type: eVTOL
  • “Piloting: Piloted or autonomous
  • “Capacity: 1 passenger
  • “Cockpit: Open
  • “Maximum speed of 72 km/h (45 mph)
  • “Range: 30 km (18.5 miles)
  • “Flight time: 30 minutes
  • “Cruise altitude: 16-82 feet (5-25 meters)
  • “Maximum altitude: 3,000 m (9,650 ft)
  • “Maximum take-off weight: 800 kg (1,734 lbs)
  • “Propellers: 8 propellers
  • “Electric engines: 8 electric motors
  • “Electric motor output: 80 kW, each
  • “Windows: Front windshield, sides are open
  • “Landing gear: Skid type landing gear
  • “Safety features: Has multiple redundancy features, advanced flight control to keep the aircraft stable in windy or gusty conditions to ensure safe flight. Distributed Electric Propulsion (DEP), provides safety through redundancy for its passengers and/or cargo. DEP means having multiple propellers and motors on the aircraft so if one or more motors or propellers fail, the other working motors and propellers can safely land the aircraft.”

Eight times 80 kW equals 640 kW total (858 horsepower), which seems a little overwhelming for such a craft.  That may account for the gross weight, probably necessary to carry the batteries for a half-hour’s endurance.

A Two-seater with Greater Speed and Endurance

Again, specifications come from eVTOL News:

  • “Aircraft type: eVTOL multicopter
  • “Piloting: Autonomous
  • “Capacity: 2 passengers
  • “Maximum speed: 130 km/h (81 mph)
  • “Flight Time: 35 minutes
  • “Cruise altitude: 300-500 m (984-1,640 ft)
  • “Empty weight: 360 kg (794 lb)
  • “Maximum takeoff weight: 560 kg (1,235 lb)
  • “Propellers: 8 propellers
  • “Electric Motors: 8 electric motors
  • “Power source: Batteries
  • “Fuselage: Carbon fiber composite
  • “Windows: Canopy over cockpit
  • “Landing gear: Fixed skid landing”
  • Safety Features are as described for the X1.

The fifth generation of “flying cars” from Xpeng Huitian, the Voyager X2 is “being tested in extreme environment,” including, “high altitudes over cities like Xining and Yushu, Northwest China’s Qinghai province.”

Empty weight ostensibly includes batteries, making for a somewhat confusing comparison with the single-seater.  With two on board, all-up weight is close to Light Sport Aircraft (LSA) restrictions and about 400 pounds less than the X1.  It also claims an extra five minutes endurance

Capable of two “driving” modes, manual and autopilot, the “autopilot function can operate an automatic flight according to a predetermined altitude, speed, and flight time along a planned route.

With offices in Silicon Valley, a move toward our shores seems likely.  We can hardly wait for the competition to begin and our questions to be answered.

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Sion Power’s EV Battery

Sion Power’s EV Battery

400 Watt-hours per kilogram is a long-awaited minimum expectation for what it will take to get electric aviation off the ground.  Sion Power® of Tucson, Arizona will introduce its Licerion® 17 Amp-hour pouch cells at the Battery Show North America in September – claiming to fulfill that expectation.  The large-format pouch cells come in a compact 810 Watt-hours per liter size, last over 800 cycles and can be charged to 80-percent of their rated capacity in 15 minutes, according to Sion.

Sion Power is shifting from its lithium-sulfur chemistry to lithium-metal technology.  Their Li-S cells powered Airbus’ Zephyr® 7 HAPS (High Altitude Pseudo Satellite) to a record for continuous flight.  According to Tucson Tech, “In 2014, lithium-sulfur batteries custom-made by Sion helped power Airbus’ Zephyr 7 solar-electric unmanned plane to fly for 11 days on sun power during the day and battery power at night.”

From Lithium-Sulfur to Licerion®

In a paper on the subject, Sion Power explains its change from lithium-sulfur to its current approach.  “However, even with this success, Sion Power was aware of an intrinsic weakness with Li-S that limited its usefulness for most applications. In 2015, Sion Power began research and development work on its next-generation rechargeable cell that overcame the limitations of Li-S.

Cross section of Licerion cell includes lithium metal anode, and a lot of proprietary materials

Sion has created three levels of protection for safe storage of energy, as reported in GreenCarCongress.com.

·         At the cell-level, electrolyte additives chemically stabilize the anode surface to enhance cycle life and increase energy. The cells do use a liquid electrolyte; however, the amount is negligible compared to traditional Li-ion cells.

·         The lithium metal anode is physically protected by a thin, chemically stable, and ionically conductive ceramic polymer barrier.

·         The pack incorporates proprietary cell compression and an advanced battery management system (BMS).

Intelligent BMS

Licerion battery packs include many safety features and an intelligent battery management system.

Using Licerion cells, Sion Power’s modular design simplifies connection and configuration of battery packs “for a wide variety of applications.”  The battery management system (BMS) includes cell balancing, discharge circuit control, state of charge (SoC), and state of health (SoH) estimation, and CAN 2.0 communication.

Standard safety features include Sion Power’s cell compression system, probably similar to other such systems that physically compress pouch cells for improved performance.  Electrical safety measures include over-charge and over-discharge protection, over-temperature protection, and over-current protection.  Each module is equipped with fuses and switches, and custom containment enclosures are available.

Competition

It will be of interest to see if Sion Power or Northvolt come to market with their battery systems soon, and how soon we will see them in actual EVs, including aircraft.  Fully available batteries at reasonable prices and with high levels of safety are essential to the future of electric flight.

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Ampaire Flies in the UK

Having completed a series of successful island-hopping flights in Hawaii, and in Scotland, Ampaire is now in Exeter, England taking part in a government-backed program, “Aimed at moving the UK towards green aviation.”  Test Pilot Eliot Seguin has moved from his Mojave, California base to take part in the endeavor, joined by fellow test pilot Justin Gillen.

Drawing a Crowd

A large contingent of dignitaries attended the inaugural takeoff of Ampaire’s electric EEL, their modified Cessna 337 Skymaster.  These included Baron Martin Callanan, the Parliamentary Under Secretary of State, Minister for Business, Energy and Corporate Responsibility at the Department for Business, Energy and Industry Strategy.

Ampaire taxiing on Orkney airfield before flying south to Cornwall in England

He shared a realistic appraisal of the new technology.  “Nobody is pretending we will be flying over the Atlantic any time soon but for short hops between two regional airports this is absolutely ideal.”

Susan Ying,  Senior Vice President of Global Partnerships and recently seen on the PBS program “The Great Electric Airplane Race,” said the hope is flights will soon be able to operate from regional airports across the UK.

“If you can scale this up for more seats in the future, it will mean that you can serve these regional airports for shorter journeys really well.”

“It will let people fly point to point really so efficiently so it will be operating at a competitive price range.”

Photo by Theo Moye 24/08/21 Ampaire, a leader in electric aviation, together with its key partners in the Government-backed Towards Zero Emissions in Regional Aircraft Operations (2ZERO) consortium demonstrate their modified hybrid electric six-seat Cessna 337 Skymaster at Exeter Airport.

“The airport already benefits from using solar energy and this is the next logical step towards greener flight in the UK.”  Cornwall is site to a great many wind farms and solar projects.

Graeme Scrimgeour, commercial estates manager at Cornwall Airport Newquay, added a note about the existing clean energy base.  “By basing an electric aircraft at Cornwall Airport Newquay, part of the energy used to charge the aircraft batteries will be generated by the adjacent solar farm owned by Cornwall Council.

The flight demonstrations are being conducted under projects funded by the UK government’s Future Flight Challenge.

Test Pilot Elliot Seguin stands with Electric EEL (its name comes from flipping its three last registration characters) on Exeter Airfield

Ampaire test pilot Elliot Sequin added, “The EEL flies very much like a conventional aircraft, with some new instrumentation for power management. said  We have flown it nonstop from Los Angeles to San Francisco and now the length of the UK without any difficulty. It is the forerunner of a new generation of efficient aircraft that will be easy to fly for pilots and cost effective for airlines.”

 Ampaire Ltd heads a UK-based consortium created to explore paths toward zero-emission transportation.  2ZERO (Towards Zero Emissions in Regional Aircraft Operations) involves the operation of hybrid electric aircraft on regional routes in South West UK, together with a study of the ecosystem required to enable the future of electric aircraft within existing airport and airline operations.

The 2ZERO bid was submitted by Ampaire Ltd and partners including Exeter Airport, Rolls-Royce Electrical, University of Nottingham, Loganair Ltd, Cornwall Airport Ltd, Heart of the Southwest Local Enterprise Partnership (HotSWLEP), and UK Power Networks Services.

If successful, it is hoped the project – which has received £30million worth of funding – will help to reduce emissions.

Lord Callanan concluded that, “The trials were “part of a range of technologies that we think will make a contribution to ‘Jet Zero’, which is sustainable aviation in the UK by 2040.”

“Aviation is something like 2-percent of worldwide emissions. So it’s something we do have to decarbonize alongside industry, alongside heating, alongside vehicles as well.”

Spreading the Word

Cory Combs, one of the founders of Ampaire, surprises by explaining his hatred of flying, but his hopes for electric aviation.

Incidental Note

Your editor’s father served at Newquay during WWII as a crew chief on B-17s and C-47s. It’s a lovely site for a flight test area.

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A battery with 560 Watt-hours per kilogram, a stable long life, and no fires.  What’s not to like?  Researchers at Helmholtz Institute Ulm (HIU), founded by the Karlsruhe Institute of Technology (KIT) in cooperation with the University of Ulm, have come up with a dual anion, nickel-rich cathode, lithium-metal battery that, although in early stages of development, may point a way forward.

Academic journal Joule reports, “High-energy batteries, in particular lithium batteries, are the key to achieve carbon-neutral mobility…. However, it is foreseen that a fully electrified mobility and transportation can only be achieved by the development of batteries employing lithium metal as the negative electrode (anode) while still granting long-term cycling performance and safety.”  Safety may be the deciding factor here, especially in electric aircraft.   Coupling the lithium metal anode with a nickel rich cathode seems to pay off for the researchers.  Along with the dual anion liquid electrolytes, they’ve managed to keep things stable and performing well.

Considering the visual impact of recent car fires on the nightly news, and instructions to park your EV outside, buyers might be forgiven for a certain reluctance to embrace an attractive, but iffy, new vehicle.

Helmholz Institute Ulm (HIU) has come up with a battery that can store 560 Watt-hours per kilogram, according to their paper.  It retains 88 percent capacity after 1,000 cycles

(As always, your editor is quick to point out 589 fossil-fuel powered cars per day self-immolated in one recent year.)  CNBC points out, “Vehicle fires are common, generally. According to the National Fire Protection Association, there were 212,500 vehicle fires that caused 560 civilian deaths, 1,500 civilian injuries and $1.9 billion in direct property damage in the U.S. in 2018.”

More Energy, More Risk

Batteries seem to be the never-ending thorn in electric flight’s side.  As batteries gain energy, they seem to become more flammable.  An ongoing recall by GM has virtually pulled all Chevy Bolts off the road, battery manufacturing defects getting the blame.  While the car company is footing the bill (over $1 billion) to replace offending battery packs, battery fire anxiety may replace range anxiety for EV owners.

Stability over its life cycle is a primary feature of HIU’s battery using dual-anion ionic liquid electrolyte (ILE)

Researchers employed a cobalt-poor, nickel rich negative electrode (anode) material along with a dual-anion ionic liquid electrolyte [ILE].  According to the Joule entry, “This electrolyte enables initial specific capacity of 214 mAh g−1 and outstanding capacity retention of 88% over 1,000 cycles with an average Coulombic efficiency of 99.94%. The Li|ILE|NCM88 cells achieve a specific energy above 560 Wh kg−1 based on the combined active material masses.”  Lower cobalt levels are promising because of the controversial conflict and child labor resourcing of that material.

From Academia to Commercial Reality?

The term “active material masses” seems to draw attention, with several comments in GreenCarCongress.com.  “Lab coin cell data is normalized to a real energy density.  This is a bit misleading.”

 

Morphology of HIU battery shows forms of materials under different methods of viewing:                                                                                                                                        (A) Rietveld refinement of the XRD pattern of pristine NCM88 powder.  (Wikipedia explanation: Rietveld refinement is a technique described by Hugo Rietveld for use in the characterization of crystalline materials. The neutron and X-ray diffraction of powder samples results in a pattern characterized by reflections (peaks in intensity) at certain positions.)
(B) Structural model of NCM88. Red, O; light blue, interslab metal; dark blue, intralayer metal.
(C) SEM micrograph of NCM88 and its elemental mapping for oxygen (O), Nickel (Ni), Cobalt (Co), and manganese (Mn).

Another reader commented, “The reference: high energy density of 560 Wh/kg—based on the total weight of the active materials, means that this does not include the inactive and polymeric binder mass. Even if they quoted the Lithium full cell energy density, it is still only a lab specimen. Until a fully developed pouch or cylindrical cell is produced, you can only estimate battery energy density.

“Cuberg does have a product with a 369 Wh/kg energy density (though poor cycle life). Depending on the configuration (pouch, 2170, 4680, etc.) energy density would be in this range. The HIU research extended the cycle life by using a dual-anion ionic liquid electrolyte.”  Combining findings by researchers with commercial developments may be a way forward.  Whether Cuberg (and by acquisition, Northvolt) uses a similar chemistry or a nickel rich cathode is not known.

Swedish Acquisition of Cuberg

Good news comes through in that regard.  Northvolt, a Swedish company, acquired Cuberg, a California-based battery developer.  Cuberg has been working closely with Boeing and other customers, including BETA Technologies, Ampaire, and VoltAero. The company’s investors and financial backers include Boeing HorizonX Ventures, Activate.org, the California Energy Commission, the U.S. Department of Energy, and the TomKat Center at Stanford.

Northvolt has plants in Sweden, Germany, and Poland among other locations, and will, “Establish an advanced technology center in Silicon Valley based on the Cuberg acquisition and is actively hiring top battery industry talent to support these efforts.”  Acting as a bridge between European and North American battery development, the center will, “Bridge ongoing research efforts between Europe and North America. It will also serve as a testbed for methodologies leveraging digitalization, artificial intelligence and machine learning.”

A comparison of cell-stack sizes of conventional lithium-ion batteries and lithium-metal batteries featuring Cuberg’s technology.  Image: Northvolt

Northvolt’s multi-billion dollar backing will help the further commercialization of Cuberg’s efforts.  “’We are very excited to join forces with Northvolt to build the future of clean energy together,’ said Richard Wang, CEO and Co-Founder of Cuberg. ‘Northvolt brings incredible technology and manufacturing capabilities that will accelerate the commercialization and adoption of our lithium metal technology. Their deep engineering experience and bold spirit perfectly complement Cuberg’s own culture of rapid innovation.’”

Close on this announcement, Arizona-based Sion Power is making news at the upcoming Battery Show North America.  We’ll follow up on that in a few days.  Finally, changes and hope are coming to the battery business.

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Pie Aeronefs, a small team of dedicated builders in Switzerland is putting the finishing touches on the UR-1, a V-tailed, battery-winged electric racer expected to fly in next Air Race E series.

“Marc Umbricht’s vision is to create a 4-seater general aviation electric aircraft that shall equal or surpass the performances of standard piston engine aeroplanes. This new generation aircraft will bring a viable and sustainable alternative on the general aviation market.”

To achieve this ultimate goal, the Pie Aeronefs team has a series of iterative designs to explore, starting with a single-seat eRacer.  The small aircraft development firm in La Sarraz, Switzerland is on track to complete the airframe of its UR-1 Air Race E machine soon.

12 Battery Packs

Innovative in the extreme, the small craft will store 12 in-series 10-kilogram (22-pound) battery packs in its wings.  Each 55-Volt pack stores 1.15 kilowatt hours of electricity.

The 13-member team chose lithium-ion polymer cells for their battery packs because they offer, “The best balance between power output and safety, despite the fire risks inherently found in Lithium-ion batteries.”  To protect the batteries and distribute their weight across the wing’s span, the group built a wing “with appropriate rigidity, as a flexible wing may damage the batteries.”  They’ve also designed “an original battery fire protection system in addition to a liquid cooling system.”  Stay tuned for more on this feature.  Part of that may come from the basalt fiber containers in which the batteries are ensconced.

UR-1’s battery packs, six in series in each wing, provide short-duration, high-output burst of power

Heat loss from the electric motor, controller, and other electronics will be dissipated through radiator plates on the inner skin of the fuselage.  This is similar to the radiator tubes that ran down the sides of the Supermarine S5 and S6 Schneider Cup racers in the 1930s.

Supermarine S5 was predecessor of Spitfire, WWII fighter. Tubes running along fuselage cooled engine, much like inner skin on UR-1 cools the motor

One Emrax Motor

All that stored energy will be fed to an Emrax 12-inch diameter motor weighing 40 kilograms (88 pounds), putting out 150 kilowatts (203 horsepower).  That’s projected to be enough to pull the 400 kilogram (880 pounds) maximum weight UR-1 around the pylons at up to 302 knots (560 kilometers per hour or 348 mph).  Racing four laps around the Air Race E course will probably see lower speeds because of the high G-force turns.  The projected 90 kilogram (198 pound) pilot will be subjected to those forces 16 to 20 times during a quick, intense race.

Fixed Gear and V Tail

UR-1 has a fixed landing gear in accordance with the rules, and slotted flaps to slow things down for take-offs and landings.

The V tail is an approach to reducing interference drag, that part of the drag profile that comes from wings butting up against the fuselage, for instance, and tail surfaces interfering with each others’ airflows.  Eliminating one part and making the remaining two perform all functions simplified the airflow, but makes it a little harder to manage the stresses on the tail cone.  That may be why UR-1 has a fairly thick protrusion – looking a bit like what ornithologists call the “Pope’s nose” on a bird.  (Your editor is not making that up.)  Much like the aircraft, the bird may need that for structural reasons, all the tail feathers poking out from the bulbous posterior and needing muscles to move them appropriately.

Certification

On June 18, 2021, the EAS (Experimental Aviation of Switzerland) association approved the UR-1 project. a crucial step to permit the first Swiss all-electric race plane to fly.

In Switzerland, EAS offers support and help to every project in the experimental aviation field. According to Pia Aeronef, “They work with the FOCA (Federal Office of Civil Aviation) and are in charge of the supervision of the construction and the maintenance of self-built planes. The EAS association is actually managing the development of more than 130 aircrafts.”

Future Plans

UR-1 is a simple, straightforward design compared to what Marc Umbricht has envisioned for the future.  Following, if all goes well, could be UR-2, a distributed electric propulsion (DEP) race plane.  That would give way to the UG-3, a certified electric General Aviation craft capable of flying 500 nautical miles at 120 knots indicated air speed.  It could land and take off in 500 meters (1,640 feet).  Finally, Umbricht foresees the UB-4, a long-range short takeoff and landing (STOL) business jet with a 6,000 NM range, cruise of Mach 0.8 (613 mph!), and a 900-meter (2,952-feet) takeoff and landing distance.

It’s nice to see an enthusiastic group keeping a timeline and their ambitions on track.  We wish them well and safe racing.

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Embraer Electrifies Agricultural Aviation

Embraer, a Brazilian aircraft maker with ties to Boeing, has been tilling the clean aviation field for several years.  Their current agricultural craft, the EMB 203, has flown on ethanol for some years – a kind of farm-to-aircraft symbiotic relationship.  Going to the next step toward clean, green aviation, Embraer has since devised an electrical powertrain in cooperation with WEG Equipamentos Elétricos and EDP.

Embraer EMB 203 making low pass along runway at Sao Paolo factory

Embraer is deeply involved in programs headed toward making the skies greener.  This includes everything from their aircraft designs to their “DIPAS PROGRAM – DIPAS (Integrated Development of an Environmentally Sustainable Product).”  This program considers “current and future environmental legislation,” alternative technologies and their life cycles.  The program works toward reducing fuel consumption, CO2 emissions, noise, and maintenance costs, while, “Increasing operational efficiency and comfort for the pilot and passengers.”

Other operations to incorporate electrification of flight include Embraer X’s Eve, the company’s approach to urban aerial mobility, and other efforts to offset or mitigate harmful emissions.  “Embraer says it will develop a range of products, services, and disruptive sustainable technologies, such as electrification, hybrid, sustainable aviation fuel (SAF) and other energy alternatives. The company claims it will also offset any residual emissions that cannot be reduced through efficiency projects, available alternative energy or advancing technology.”

The Plane from Ipanema

Flying since 2004 on ethanol, the predecessor to the current EMB 203 was an early attempt to reduce carbon emissions.  Some find this approach controversial, since ethanol production often entails converting food crops such as corn into aviation fuel.  Electricity can be obtained from more sustainable resources, and thus might be more acceptable to environmentalists and those worried about feeding a hungry world.

The base design has been flying since 1970, and Embraer plans to use it as a testbed for electric power.  Its payload of 950 kilograms (2,094 pounds) is great for spraying large fields, and highly useful for carrying a large battery pack.  EDP-funded batteries combined with the “very light electric motor [from] the large Brazilian electrical company WEG” will allow enhanced endurance.  Technology developed on the Ipanema will be transferred to use on the EVE eVTOL (electric Vertical Take Off and Landing) project and probable future electric projects.

Luis Carlos Affonso, Vice President for Technology and Development at Embraer, explains the importance of the Ipanema.  “The first flight of an aircraft is always an important milestone and the start of our first of… ten emission-free electric aircraft is also an important contribution of our teams and partners on the energy transition in the industry. We strive to find solutions that enable a more sustainable future for aviation, and innovation becomes one along the way Play a key role.”

Embraer’s electric agplane with some of its 1,800 builders, flanked by civilian and military craft produced by Embraer

First flight tests include evaluation of performance, control, heat management, and operational safety.  Embraer hopes to validate computer simulations, laboratory tests and integration of the technology, ongoing since the second half of 2019.

President and CEO Francisco Gomes Neto. “We recognize the urgency of the climate crisis and we are fully committed to a more sustainable future.  We are stepping up our efforts to minimize our carbon footprint by remaining dedicated to innovating solutions that have a broader impact for our customers, our local communities and our aircraft.”

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Three Massachusetts Institute of Technology (MIT) researchers may be on the track of producing hydrogen from a reaction between aluminum (the scrappier the better) and water.  Their “simple way” of generating H2 from aluminum and water can take place anywhere, according to the researchers.

Since groups like ZeroAvia and Pipistrel with the DLR (German Space Agency) and HY4 are working toward at least intermediate-range hydrogen-powered flight, an inexpensive way to produce the gas would be a blessing.  Current methods of producing H2 from fossil-fuel-related materials can be more detrimental to the environment than the promise hydrogen would otherwise bring, however.

Corroding but Not Rusting

Dr. Laureen Meroueh along with Professor Douglas Hart and Professor Thomas Eager at MIT have found a way to react aluminum with water at normal room temperature, leading to the formation of aluminum oxide while releasing hydrogen gas.

Under normal conditions, aluminum exposed to water develops a coating of aluminum oxide.  Stanford researchers in 2000 discovered why this does not become destructive “rust” like that on steel.

Aluminum aircraft don’t corrode because of protective coating. Alclad  Ryan SC-W shines because of labor-intensive polishing

Gordon Brown, Jr., the Dorrell William Kirby Professor of Earth Sciences explains, “Water actually changes the structure of the solid surface.  In the journal I, Brown and others presented the first atomic-level model of what happens when water and aluminum oxide meet. ” As the name would suggest, aluminum oxide is atoms of aluminum and oxygen bonded together.

“But Brown and Trainor discovered that, when water molecules come in contact with aluminum oxide, the aluminum and oxygen atoms on the surface move apart — in some cases separating by more than 50 percent compared to their normal molecular positions.

“As a result, when the outer layer of aluminum oxide gets hydrated or wet, its structure changes just enough to become chemically inert and thus unable to react rapidly with additional water molecules or atmospheric oxygen. This change in molecular structure is why aluminum oxide metal resists corrosion.”  This 20-year-old discovery is key to the MIT researchers’ ability to make H2 from oxidized aluminum.  It takes a little fine tuning, though.

A Little Tuning

The thin oxide layer on the aluminum keeps the aluminum from corroding further, but also prevents it from reacting any further with water.  To counter that, researchers had Novelis, Inc. prepare pure aluminum and special alloy samples with coatings of, “0.6% silicon (by weight), 1.0% magnesium, or both—compositions that are typical of scrap aluminum from a variety of sources.”

The nifty part of this comes from being able to pretreat the aluminum, transport it anywhere, and then generate the hydrogen on site.  More frugally, such pretreatment could take place anywhere with scrap aluminum, an abundant resource near any population center with convenience stores.

At a wildly simplified level, these coatings act as blockers against the creation of further protective oxidation, but allow reactive things to happen – generating hydrogen when the treated aluminum comes in contact with water.

Laureen Meroueh PhD ’20, professors Douglas P. Hart and Thomas W. Eagar used a technique “first introduced by Jonathan Slocum ScD ’18 while he was working in Hart’s research group.”  They pretreated,  “the solid aluminum by painting liquid metals on top and allowing them to permeate through the grain boundaries, as shown in the diagram below.”

Coating aluminum to prevent protective oxidation.  The idea of permeating metal with a liquid may seem counterintuitive, but is necessary to the process

Researchers found the type of coating (a limited sample, admittedly) changes the amount of hydrogen generated and the time over which the reaction takes place.

Aluminum coated with a layer of 0.6-percent (by weight) silicon spikes quickly in forming hydrogen, which a coating of 1.0-percent magnesium enables a high early reaction and a longerl period of production.

Grain size plays a part, smaller grains of aluminum reacting with various coatings to produce higher reaction levels, but varying reaction durations.

Aluminum grain size plays a factor too, enabling permeation by the liquid metal coating

Logistics are important in being able to provide energy in diverse locations.  Recent climate-based traumas (The Texas winter, for instance) show the dangers of having large, highly dispersed needs served by highly localized resources.  Shipping volatile fuels such as oil, gasoline, and liquified natural gas is hazardous, whether by truck, train, or pipeline.  Most of the ingredients for generating hydrogen at its point of use are readily available for most elements of MIT’s approach.

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