New Atlas is reporting the first flight of a crewed electric aircraft using solid-state batteries occurred in Florida earlier this month, and it’s being heralded as a breakthrough in advancing electric aviation. The new batteries were installed in a modified Pipistrel motorglider called the Helios Horizon. The flight tests were mainly done to validate weight and balance for the new storage system, which replaced a standard wet cell lithium ion setup. The increased capacity of the solid-state cells is already documented at 410 watt hours per kilogram, a 60% increase over lithium ion batteries. For perspective, gasoline has 12-13,000 watt hours per kilogram of energy density but the heavier internal combustion engines and their relatively inefficient conversion of energy (25% to 40%) significantly eat into that advantage.
The aircraft also uses a regenerative system that charges the batteries with the prop on descents, and there are solar cells on the wings which, combined, significantly extend the range of the glider. Electric car manufacturers are already pouring billions into bringing solid-state batteries to market and systems capable of 500 watt hours are being tested. Miguel Iturmendi, who owns Helios and flew the glider in Florida, said he expects the solid-state performance to increase another 40% within two years. The other advantage of the system is its fast charging capability. It can be charged to 80% in 15 minutes.
Gliders are a perfect platform for electric drive. Get to altitude, stow the motor, go soaring! No need for 700NM of range. It would be nice to know the performance of the system as designed. How many minutes at full power, how much reserve when climbing 5000 feet? For those who don’t know, 1HP is the ability to lift 550 pounds 1 foot in 1 second. Climb in an aircraft is no different, HP does the work. Lifting a 1200 pound glider 5000 feet at 500FPM would require (ignore losses) about 20HP for 10 minutes. That may not seem like much to those of us who fly conventional aircraft, but for battery power, that’s quite a task. Ignoring losses, the battery must output about 15kW (15,000W) worth of power to produce 20HP. And have enough reserve to do it at least one more time. All very do-able.
Although production 4680 cells now top 303Wh kg and next gen 340Wh kg. SS cells are not 60% better than conventional lithium batteries. More like 25%, tech for tech.
Given the claim for fast charging, how are these at tolerating it (thermal runaway and long term capacity impact) vs existing tech?
SS batteries are said to be much less prone to fail from dendrite growth due to the actual physical barrier. Also they can tolerate much more heat without damage. No liquids to fail. Some can operate as high as 300ºC!
thx for the insight
Whats new here?
For historical reference: In 1990 Eric Raymond flew a solid state battery powered solar airplane from California to North Carolina. He built his Sunseeker 1 himself, it weighed about 155 lbs and carried ~30lbs of Ni Cad batteries in the spars.The airplane had a ~4HP motor driving a 2 bladed 20oz folding propeller (that I designed and built). The batteries provided for a maximum 15min of power. The rest of the trip was accomplished by Eric’s expert soaring capabilities on several legs in about 5 weeks.The batteries were always and only charged by solar power. Eric has since built the Sunseeker Duo which has even more spectacular performance using a Solar paneled wing mated to a super light fuselage built from the Stemme S10 molds. He and his wife fly the airplane regularly in the Alps.
What’s new here is the battery. Ni-Cd batteries are not solid state batteries. Solid state batteries use solid electrolytes instead of the liquid or gel electrolytes used in traditional lead acid, Ni-Cd or Li-ion batteries (like those used in the Sunseeker). Solid state batteries exist and have for a long time, but they are currently difficult and expensive to manufacture. As Russ mentions in the article, solid state batteries are more energy dense, offer rapid recharging and are less prone to thermal runaway. Mass manufactured solid state batteries will be a game changer in battery technology – especially for electric vehicles.
Thank you wrong way for your enlightened comments
Douglas has commented a few times over the years on AvWeb and now its more worthy spiritual successor, AvBrief. You are the first to make reference to my pseudonym. We must be of similar vintage.
Getting to 50% equivalent of petrol is the holy grail
Glad to hear solid-state batteries work – but at what cost, compared to the Li-ion batteries used in electric cars?
Very interesting development. New technology always moves in fits and starts, but the arc for renewables over the last 20 years has pretty much confounded the initial naysayers. The same will be true for aviation, both the fits and starts, and the eventual progress.
Based on the information in this article, the advent of solid state batteries could give evtol commercial aircraft the ability to make regional flights of more than 100 miles to important destinations. This may be what the designers and operators of these aircraft are counting on to recover the huge investment that has been made in evtols.