Keeping Battery Fires at Bay

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Fires on or in aircraft are anathema, leaving a pilot and passengers with few options. Even a laptop starting to smoke in the cabin will cause an emergency descent and a diversion to the nearest airport. As designers incorporate larger lithium batteries into new aircraft (and they are essential to motor-driven planes), the need to keep things from self-igniting becomes imperative. Researchers at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, working with funding from the Joint Center for Energy Storage Research (JCESR) discovered, “That adding two chemicals to the electrolyte of a lithium metal battery prevents the formation of dendrites – ‘fingers’ of lithium that pierce the barrier between the battery’s halves, causing it to short out, overheat and sometimes burst into flame.” Preventing these shorts will lead to the next-generation batteries being able to take advantage of lithium-sulfur and lithium-air technologies with up to 10 times the energy per weight of batteries now used in …

Trapping Light: A “Perfect” Solar Absorber?

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

The news item from David L. Chandler at the Massachusetts Institute of Technology (MIT) claims that researchers there have come close to realizing the “ideal” for solar absorption, trapping and containing all of light’s wavelengths that reach earth’s surface from the sun.  This absorbed sunlight is converted to heat by a two-dimensional metallic dialectric photonic crystal, which can absorb sunlight from a wide range of angles and withstand extremely high temperatures.  Even better, it can be made cheaply and in large quantities, according to MIT. One aspect of the design that might make it difficult to use on aircraft is its high operating temperature.  A solar-thermophotovoltaic (STVP) device, the energy from the sunlight hitting the cells is “first converted to heat, which then causes the material to glow, emitting light that can, in turn, be converted to an electric current.” Having worked on an earlier version of STVPs, the researchers noted that the solar cells had many hollow cavities.  Nature …

The New Mythbusters: Slow Charging May Not Make Batteries Last Longer

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

For the last 60 years, your editor remembers the oft-repeated advice from garage mechanics and now lithium-ion advocates that slow charging is the way to make your batteries last for many cycles.  Where does this put Tesla, for instance, with its 20-minute Superchargers?  Are you damaging your expensive cells by being in a hurry? In yet another example of counter-intuitive thinking at work, researchers at SLAC, the National Accelerator Laboratory at located on the Stanford University campus have challenged several tenets of conventional battery wisdom.  According to PC World, their work, “published on Sunday in the Journal, Nature Materials, challenges the commonly held notion that slowly charging a battery helps prolong its life and that it’s damaging to a battery if a large amount of energy is withdrawn in a short time.” William Chueh, a senior author of the paper and researcher at the Stanford Institute for Materials and Energy Sciences (SIMES), told the magazine, “’We’ve always thought of a …

Angela Belcher Continues Making Batteries with Viruses

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Three years ago, in one of our earliest entries, this blog reported on the blending of biology and chemistry in a bionic battery created by Massachusetts Institute of Technology researcher Angela Belcher. She was honored with a press briefing with President Obama, MIT President Susan Hockfield and her prototype battery, and used the occasion to encourage federal funding for such ventures.  In a later visit to her laboratory, the President accepted a business card with the periodic table, saying he would consult it periodically. She has turned her bionic battery research to improving the chances for lithium-air batteries to reach that magic 500-mile figure ( or at least 550 kilometers or 341 miles), and has explained her approach and progress in a Nature Communications paper and in the video below. Since Dr. Belcher has been using a biological approach in her research for the last decade, it was natural for her to use genetically-modified, non-toxic viruses to grow” spiky surfaces” …

SolidEnergy Teams with A123 for High Energy Density Battery

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Take two Massachusetts Institute of Technology (MIT) business incubator realizations, mix their strengths and watch for the potential breakthroughs that could come in the form of high-energy-density batteries. According to its web site, “SolidEnergy is developing a safe, high energy density, and wide temperature capable rechargeable battery that has the potential to transform the consumer electronics, electric vehicle, and downhole exploration (as in well drilling) industries. The core technology is called a Solid Polymer Ionic Liquid (SPIL) lithium metal battery.” Founded in 2012, “one of the toughest years in the battery industry,” SolidEnergy’s “…objective is to develop an insanely great next generation battery and commercialize it in the fastest and most efficient way.” This decidedly brash approach needs a steadying hand at the wheel, which is where its partnership with A123 Systems comes into play. A123’s first collaboration under its expanded research and development model combines SolidEnergy’s SPIL technology with “the mature cell design and prototyping capabilities of A123.” This would help …

Lighter, Stronger, and Morphable

Dean Sigler Sustainable Aviation 2 Comments

If you have a pre-teen roaming around the house, you more than likely know the shared delight of assembling the biggest possible thing you can make from Lego® blocks.  There must be something of that delight in the Center for Bits and Atoms at the Massachusetts Institute of Technology (MIT). There, researchers have invented, “A new approach to assembling big structures — even airplanes and bridges — out of small interlocking composite components,” according to a story by David L. Chandler of the MIT News Office. Neil Gershenfeld, director of the Center, and post-doctoral student Kenneth Cheung recently co-authored a paper published in the journal Science, in which they describe assembling strong lightweight structures with “cubocts,” lattice structures that are the lightest and strongest in existence, as stated in the Center’s publications. The Center claims 12.3 megaPascals, or 1,784 pound per square inch strength for the 7.3 milligrams per cubic centimeter material (about 0.45 pounds per cubic foot).  Balsa wood, …

Thinner than Kleenex®, as Powerful as the Sun

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

David L. Chandler of the Massachusetts Institute of Technology (MIT) News Office reports that an MIT research team headed by Jeffrey Grossman has found a way to make sheets that push “towards the ultimate power conversion from a material” for solar power.  His team has managed to fabricate molecule-thick photovoltaic sheets which could pack hundreds of times more power per weight than conventional solar cells. Senior author of a new paper on the team’s study in Nano Letters, Grossman found that despite the interest in two-dimensional materials such as graphene – only an atom thick – few have studied their potential for solar applications.  Grossman says, “They’re not only OK, but it’s amazing how well they do.” Stacking sheets of graphene and materials such as molybdenum disulfide would make solar cells with one to two percent efficiency in converting sunlight to electricity.  That seems disappointingly low compared to the 15 to 20 percent efficiency of commercially available silicon solar cells. …

Ionic Thrusters Offer Quiet Flight

Dean Sigler Electric Powerplants, Feedback, Sustainable Aviation 3 Comments

Gizmag and Science Daily both covered a propulsion system that’s been with us for many decades, but which is just now seeing practical applications in space flight, and may be adapted to terrestrial winged vehicles. Your editor might have passed it over as overhyped, but the research came from the Massachusetts Institute of Technology (MIT) and was published in The Proceeding of the Royal Academy – two good indicators of veracity. Jennifer Chu of MIT’s News Office explains, “When a current passes between two electrodes — one thinner than the other — it creates a wind in the air between. If enough voltage is applied, the resulting wind can produce a thrust without the help of motors or fuel.”  That phrase, “If enough voltage is applied…” is a significant qualification. “Electrohydrodynamic thrust,” or “ionic wind” has been known since the 1960s, but limited to hobbyists and science fair projects.  This video from China demonstrates the use of electric thrusters to …

On a Clear Day, I Can See My iPad

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Dr. Brien Seeley, President of the CAFE Foundation, shared the news of an exciting breakthrough that could make the see-through parts of an airplane’s solar collectors.  Most solar collectors have a black or near-black look because they are absorbing light in the visible spectrum.  Pulling energy from infrared or ultraviolet spectra invisible to the human eye allows Ubiquitous Energy’s Clearview Power translucent film of to be laid over iPad and Kindle screens and keep them charged constantly. Consider the possibilities of such films covering the Plexiglas or carbonate canopies on aircraft.  Even those portions could then be energy collectors.  On craft such as electric sustainer motor powered sailplanes, the glazed area comprises a large part of the total fuselage surface area. According to the MIT Technology Review, “…The transparent solar cells are made of various organic layers, deposited one at a time on top of a glass or film. This process could easily be integrated into thin-film deposition systems found …

New “Leaf” Turns Over More Energy

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Scientists have been working on imitating nature’s ability to photosynthesize the sun’s energy, much as plants turn that energy into food for their health and growth.  Daniel Nocera, for instance, created an artificial leaf that split water into oxygen and hydrogen that could fire up a small fuel cell and run an electric light.  According to a Science Pub lecture your editor recently attended, an eight-ounce glass of water can power a 60-Watt bulb for 20 hours.  Nocera, in a Pop! Tech talk, claims an Olympic-size swimming pool could supply all the world’s energy needs. Nocera now works at Harvard, but researchers at Massachusetts Institute of Technology (MIT), his former home, are taking his work further, detailing all the limitations that keep his “artificial leaf” from giving off more storable energy. As explained in the MIT press release, “The original demonstration leaf, in 2011, had low efficiencies, converting less than 4.7 percent of sunlight into fuel… But the team’s new …