Toshiba dramatically increases energy density of Li-ion battery
By Darren Murph 
posted April 15th 2009 10:12AM
posted April 15th 2009 10:12AM
The last time we heard of lithium titanate battery technology was when learning about the £120,000 Lightning GT, and while we've no way to confirm, we're definitely hoping that the latest development from Toshiba ensures that we're talking about it far more frequently than once per year. According to a report over at Nikkei's Tech-On, said outfit has crafted a cell of a Li-ion secondary battery (aimed at electric vehicles, mainly) that sports an energy density as high as 100Wh/kg. Needless to say, the invention relies on lithium titanate for its negative electrode, and considering that Tosh is currently producing a 4.2Ah cell with an energy density of around 67Wh/kg for electric bicycles, it's easy to see what kind of improvement we're staring at. Now, if only this stuff could be applied to AA cells, our power-gulping camera flash would be forever grateful...
Tangents.
Nice to see so many people *manipulating* the figures to suit their argument.
So lets go back to basics, and stick to the article, shall we.
The energy density (Wh/kg) is the core of this article.
The figure quoted for this battery is "as high as 100Wh/kg", so we'll just call it 100Wh/kg, which is the same as 0.1KWh/Kg.
With me so far.
The figures I located for the energy density of gasoline and diesel respectively were 12.7KWh/Kg and 11.6KWh/Kg.
Now, when I went to school, if you divided 12.7 and 11.6 by 0.1, you get 127 and 116.
At no point in this article are the relative *merits* of either stored electrical energy, gasoline or diesel mentioned.
However, unless I'm much mistaken, as you use up the energy stored in a cell, it does NOT get any lighter, unlike using up stored gasoline/diesel. Therefore the vehicle ICE vehicle gets lighter as it travels, unlike the electric vehicle.
And no, I haven't forgotten that you still have to transport gas/diesel to the filling station. But you also have to transport electricity to a recharge point.
So, back to my point.
Yes, advances are being made in cell technology.
Yes, this is a good thing.
And yes, eventually, electric vehicles will be viable.
But not yet.
So can we all chill the hysteria. There's a LONG way to go yet.
Example;
The Chevy Volt was being featured on the BBC news here last night.
40 mile(ish) range, with backup generator (petrol/gasoline driven).
Price- £30,000 (or thereabouts)
UK Gov talking up a £5K 'grant' to encourage people to go to EV's
Still leaves you having to find £25K, plus the installation of a recharge point at home.
And if you use it to commute to work, how do you recharge it when you get there so you can get home without having to use the generator?
How do you convince your employer to install charge points?
Then again, at £30K a pop, how many people are realistically going to be able to afford to buy one?
How long is it going to take before you begin to make back the up-front difference?
Many people have compared the development of viable, mass market EV's to the development of the first viable mass market ICE vehicles. There is one major difference.
When the first mass produced cars came along, they only had the horse to contend with. It wasn't too difficult to produce something cheaply, reasonably reliably, and plentiful enough to displace the horse.
EV's on the other hand, are going to have to displace the now ubiquitous ICE. And the massive support infrastructure that now exists for them. That will need to be replaced too.
As I said. There's still a LONG way to go.
The new unibody MacBook Pro 17" has a 95Wh battery which weighs 570 grams. That gives 167Wh/kg.
CraigJ
"The effective density of gasoline is about 1,200 to 1,800 per kg, because 85% to 90% is waste heat."
That's the important part. But besides that, the energy density of LTO batts isn't the point, the point is how fast they charge and how many times they can charge.
This isn't so useful in cars, because you would normally charge at night, and once in a while do a quick charge. However in uses like buses, trash trucks, container movers at ports, where the vehicle uses the same route over and over, these can be very useful. Put a fast charger at the end of the bus route (or trash truck), and charge it for 6 minutes, and you have a fully electric machine, only using a relatively small battery. Sure the charge is big, but quite feasible (300Amps at 600Volts!). Big electric trains do this all the time.
See www.nanobus.org for details.