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    U.S.-based startup Wright Electric and British budget airline Easy-jet have announced a partnership to build electric airplanes. The goal is for the all-electric plane to be capable of ferrying 150 people on flights under 300 miles. 

    Although a few years out it is an important first step

    Wright Electric first caught the world’s attention back in March at Y Combinator’s Demo Day W17. As you may have guessed from their name, the American startup wants to develop electric airplanes, an idea that was praised by the head of Y Combinator’s accelerator program.

    Wright Electric’s idea is to develop an all-electric aircraft that’s capable of ferrying passengers for short flights —like those from New York to Boston, London to Paris, or Seoul to Jeju. This goal aligns with those of low-cost British airline easyJet, and today, the company announced a partnership between the two organizations.

    “A collaboration with U.S. company Wright Electric will support the goal for short-haul flights to be operated by all-electric planes,” easyJet noted in a press release. “Wright Electric has set itself the challenge of building an all-electric commercial passenger jet capable of flying passengers across easyJet’s U.K. and European network within a decade.”

    The British budget airline has reportedly been working with Wright Electric since March, providing the startup with guidance on designs and operations, according to Wright Electric co-founder Jeffery Engler.

    CUTTING DOWN COSTS

    Ultimately its economic drivers that will bring about change. Short-haul flights account for 30 percent of all flights and 50 percent of regional flights. As Engler previously pointed out, that’s a $26 billion market. Electric airplanes that wouldn’t need jet fuel would mean even cheaper flights for a budget airline like easyJet.

    “For the first time in my career, I can envisage a future without jet fuel, and we are excited to be part of it,” easyJet CEO Carolyn McCall told Electrek. “It is now more a matter of when, not if, a short-haul electric plane will fly.”

    Image Credit: easyJet

    Back in March, Wright Electric revealed their plans for an all-electric commercial aircraft called the Wright One. The plane would be capable of ferrying 150 people on flights under 480 kilometers (300 miles). That’s roughly equivalent to the abilities of a Boeing 737. The only difference would be that the Wright One is battery powered.

    Although air transport contributes only 9 percent of carbon emissions in the U.S., having all-electric airplanes for short-haul flights would be most welcome. In the fight to decrease our global carbon footprint, we’ll take all the wins we can get.

    Batteries 

    At the moment this could be the sticking point.

    Wright has taken a close look at the economics of rechargeable batteries for use in large airliners.
    We asked ourselves this question, “If we want to build an electrically powered airliner that offers cost savings over a conventional airliner, how long must the batteries last?”
    The answer is a sliding scale, depending on the cost of electricity and jet fuel. But the answer sits squarely in the multiple thousands of cycles.
    Here is a bit more on our thinking about battery cycle and calendar life:
    Less Depth of Discharge, More Cycle Life 
    With all lithium ion chemistries currently on the market, smaller charge-discharge cycles (narrower SOC band) are non-linearly accretive to battery life. In other words, if you get 1,000 cycles out of a battery at 100% depth-of-discharge (DOD) cycling, you will get more than twice as many equivalent cycles by doing 50% DOD cycling, many more than 4x at 25% DOD, etc. The takeaways from this: Charge a little bit at a time, opportunistically. Oversize your battery so that each mission does not fully drain the battery.
    Temperature Affects Calendar Life 
    Degradation of lithium ion batteries occurs via two primary routes, typically called cycle life and calendar life. Cycle life refers to the number of charge-discharge cycles that the battery sees, while calendar life degradation happens via time, just sitting around. Calendar degradation mechanisms are exacerbated by temperature. In this case, higher temperatures are worse for capacity fade over time. Thermal cycling may also cause capacity to fade. The effect of flight conditions on battery cycle life must be studied carefully.
    Higher Voltage More Problems
    Similar to higher temperatures mentioned above, calendar degradation is also exacerbated by higher voltages. Electrolyte improvement may improve cycle life in high voltage applications. There could be additives that improve discharge capacity because they reduces SEI formation and thus free captured lithium, but a non degrading electrolyte is key to cyclability. Keep an eye on that as new battery chemistries emerge.
    Slower Charging and Discharging is Better
    As mentioned above, degradation of lithium ion batteries tends to come from cycling and calendar effects. On the cycling side of the ledger, the slower the battery is charged/discharged, the longer the lifetime, typically. Rapid recharging between missions may harm the battery’s cycle life leading to unfavorable economics. If you swap battery packs instead of rapidly recharging them, you may be in a better place economically.
    Forget about the Memory Effect
    In the early days of portable electronics, when Ni-Cd and NiMh batteries were commonplace, the “memory effect” of these cells was well known. In short, if you consistently charged and discharged these cells within a narrow range of state of charge (SOC), they seemed to “remember” this method of operation and lost significant capacity. Lithium Ion does not suffer from this behavior.

    Reference

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    Laser, Graphene Enable Fastest Light-Driven Current
    Paper supercapacitor addresses power/energy density trade-off
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