Lithium-Sulfur Batteries Power High-Altitude Aircraft For 11-Day Flight

OCT 7 2014 BY MARK KANE 14

Li-S Technology Overview by Sion Power

Li-S Technology Overview by Sion Power

Lithium sulfur (Li-S) batteries reach another milestone as the Airbus Defense and Space Zephyr 7 prototype High Altitude Pseudo-Satellite (HAPS) aircraft finished a southern hemisphere winter weather flight of over 11 days duration controlled by satellite communications.

Because of short winter days, along with over 250 hours of flight, Zephyr 7 flew longer on batteries than on the solar array.

The ultimate goal for High Altitude Pseudo-Satellite (HAPS) aircrafts is year-round capability.

The Zephyr 7 is a solar/battery powered all-electric UAV equipped with Sion Power (Li-S) batteries. Energy density of those cells stand at 350 Wh/kg. The whole aircraft’s weight is just over 110 lbs. (50 kg) and it has a wing span of 70 feet (22.5 m).

“The custom built Li-S battery pack was designed and assembled by Sion Power in Tucson, Arizona. The battery utilized Sion’s unique, high specific energy Li-S cells which provide 350 Wh/kg, the highest available for a rechargeable battery. The Li-S battery pack was carefully engineered to minimize total pack weight. Advanced electronic controls maintained the battery condition throughout the flight.”

“Once launched, Zephyr can remain above a region for weeks delivering persistent services at a fraction of the cost of satellites and is significantly more cost effective than other conventionally powered manned or unmanned aircraft. This latest flight is part of an ongoing program to develop Zephyr into a year-round capability and provided the data which will be used to refine the design for the Zephyr 8, the next generation of HAPS.”

Sion Power’s CEO, Dr. Dennis Mangino stated:

“This flight represents a further major accomplishment for Sion’s lithium sulfur technology proving the viability of our high energy, rechargeable battery system. As a winter flight, the aircraft flew longer on the batteries than on the solar array, a world first.”

Jens Federhen, head of the Airbus Zephyr program, commented:

“The performance of the Sion Li-S battery was excellent and the Zephyr was able to exploit the full capacity of the battery due to the high reliability and consistency of the cells, essential for this winter flight. Sion’s Li-S batteries are an enabling technology for the Zephyr program and we look forward to joint future flights.”

Link to more detailed info on the Li-S battery technology from Sion.

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14 Comments on "Lithium-Sulfur Batteries Power High-Altitude Aircraft For 11-Day Flight"

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Nerd Attack!

Here are the gory details on the battery:

So they are not going to be popped into a car anytime soon due to cycle life and stability at high temperatures, but it is still hopeful.

Li-S is where I’m pinning my hopes of seeing big improvements in battery performance over the next 5 years. By 2020 I’m expecting Li-S with Si anodes, about 500-550Wh/kg and 500-600Wh/L. Compared to today’s Li-Ion, they aren’t that much more space efficient (though the reduction in safety circuitry may help[1]) but they’re way lighter. Cycle life will improve to about 500, which would be plenty for the long-range EVs these batteries will be outfitted in (250 mile range * 500 cycles is 125K miles).

The issue is price – will they be able to mass-manufacture these in sufficient quantity (the raw materials of sulfur and silicon are cheap enough) to be able to compete with the traditional Li-Ion gigafactories of the world. Or better yet, will the gigafactories of the world turn over their production technologies so soon as to give Li-Ion the boot and install Li-S production hardware?


Dr. Kenneth Noisewater

Well that’s also full-cycles, which should be somewhat avoidable with adequate over/undercharge buffers?

Once again a bad graph. What’s the numbers on the Y-axis?

It’s Wh/kg, I am pretty sure.

The graph is out of date, if it ever was up to date. Tesla’s batteries are beyond the lithium-ion bubble, and more energy dense in Wh/l than even the future LiS bubble. Of course, Wh/kg is more important for an airplane, but not for a car.

I think it is possibly Energy density Wh/ltr on the x axis as labelled, and power density on the y axis.

Nah, I’ve seen similar graphs before. There is one at

for instance.

You’re right.

I tracked the graph down and:
‘Over 600 Wh/kg in specific energy and 600 Wh/l in energy density are achievable in the near future.’

Mark and staff:
Any chance of including link info?
It makes life a lot easier for those interested in looking deeper.

Hi Mark.
I meant at the foot of the article, where you embedded the image.
That is what I dug out, as it was not referenced.


Many thanks, Eric.
If folk can possibly add where they got the info when they publish the article, it would be really helpful, and save digging and guessing!

From what they are saying this battery has three times the power of the battery they are putting into the Mitsubishi i-miev. If you could put this battery into Mitsubishi i-miev it would give the car a 186 mile range. If this could happen it would make the i-miev a very nice car in that the range is the only thing I don’t like about it.

Not quite…

Seems like Li-S is a more lightweight material (the y-axis, but takes up just as much or possibly more space than Li-ion (that’s the x-axis).

So it is way more suited for aircraft, where weight is paramount and you can possibly spread the batteries along the body and wings.