Bicycles

Williams demonstrates sodium-ion-powered proof-of-concept e-bike

The e-bike, with its sodium-ion battery pack
The e-bike, with its sodium-ion battery pack
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The sodium-ion battery pack, which was made by Williams, incorporates sodium salts made from common salt
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The sodium-ion battery pack, which was made by Williams, incorporates sodium salts made from common salt
The demonstrator bike was developed by British start-up Faradion, in partnership with Williams and Oxford University
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The demonstrator bike was developed by British start-up Faradion, in partnership with Williams and Oxford University
The e-bike, with its sodium-ion battery pack
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The e-bike, with its sodium-ion battery pack

Although lithium-ion batteries perform far better than alkalines, they're also relatively costly, the lithium salts used in them aren't widely available, and they sometimes catch fire. That's why some scientists are suggesting sodium-ion batteries as an alternative. To that end, Williams Advanced Engineering recently demonstrated that they could be used to power an electric bike.

The demonstrator bike was developed by British start-up Faradion, in partnership with Williams and Oxford University.

Its sodium-ion battery pack, which was made by Williams, incorporates sodium salts made from common salt. It consists of four 12-cell modules. The pack was made rather large, in order to keep costs and manufacturing complexity down, although Williams claims that a more refined commercial version would be similar in size to a lithium-ion pack of the same capacity.

The sodium-ion battery pack, which was made by Williams, incorporates sodium salts made from common salt
The sodium-ion battery pack, which was made by Williams, incorporates sodium salts made from common salt

Williams' communications manager James Francis tells us that the e-bike "performed well with no issues," although the demo (which took place this Thursday in a parking lot) wasn't extensive enough to get specs on factors such as range.

"Whilst lithium-ion is still the dominant choice of chemistry, sodium-ion is a fascinating alternative that could have real benefits in terms of cost and availability," says Williams technical director, Paul Mcnamara. "We have worked closely with Faradion and Oxford University to explore its potential and today was about showcasing the concept in a real world application for the first time."

Source: Williams Advanced Engineering

6 comments
Jérémy Henriquel
Interesting news, it's nice to see alternatives to the dictatorship of lithium. However you also forgot to mention in the introduction the limited worldwide reserves of lithium (39 millions of tonnes worldwide according to the USGS), its toxicity and the environmental impact of manufacturing it and its difficult recycling. http://www.kitco.com/ind/Albrecht/2014-12-16-How-Green-is-Lithium.html Indeed, it is expected that 2 billions cars (excluding two and three wheelers) will be on the roads by 2050. If we intend to have a range of 400 km (a range where EV would begin to be mainstream), we need at least a 70 kWh pack thus a total capacity of 140 TWh. With a requirement of 320 g/kWh of lithium, we would need around 44 millions tonnes of lithium without process losses, which is not enough. Now add electric scooters, smartphones, tablets and energy storage (a market at least two times bigger than EV) and we are in big trouble. On the other hand, we don't have to worry about sodium which is the most common metal cation in seawater (10 g/L which is 100 millions times more abundant than lithium in seawater) and is harmless because it constitutes normal table salt.
-dphiBbydt
I wonder if they have solved the anode swelling problem prevalent in Na-ion batteries. Maybe the fact they mention the batteries being bigger than they potentially could be is a hint that there's still work to do. The key with Na-ion batteries is not the energy per kg but more the mechanical aspects that reduce longevity (degradation during charging). The sodium ions are relatively big and swell the anode during charging causing structural problems.
PeterMortensen
Why can't journalists write something that provides a valid comparison when a new technology is presented. When it comes to battery chemistries there are a list of different properties that are relevant. These includes cost, power density, charging time, maximum power drain, durability, toxicity and others. Often you can hear that now some new chemistry is better in a particular property, but nobody mentions the fact that it's worse in others. I can rename a super capacity to "battery" and claim it to have the world's fastest charging time, best maximum power drain and best durability, but it will fail for real battery powered applications due to very low energy density. Using super capacitors an electric bike would become too big and heavy. The article also fails to point out that a dominant battery technology in markets like China is actually still lead acid batteries for electric bikes.
Fretting Freddy the Ferret pressing the Fret
@-dphiBbydt, If you had followed the link to the sodium-ion batteries, you would have found that there's a method around that problem you mention. Where lithium-based batteries fail, and sodium-based batteries prevail is natural abundance. Lithium-based batteries will fail to meet long-term future demand as its volume in electric vehicles and homes will need to rise dramatically. There aren't nearly enough lithium reserves. It's only a matter of time before the switch is made to other elements such as sodium.
Douglas Bennett Rogers
Lithium mining stocks are very depressed!
stew
I heard that Nicola Tesla powered an electric car without a battery