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Discussion in 'Battery Discussion' started by dpeilow, May 22, 2009.
'Air fuelled' battery tech invented in Scotland â€¢ The Register
Lithium Oxygen Battery
Both of these are very impressive if true. 2-4x density is really all we need in practical circumstances. That's enough for ~500-1000 miles on a Roadster sized 450kg pack or ~250-500 on a 225kg pack.
With the claimed densities of these kind of pack, range can greatly exceed what is even possible in most gasoline cars (though it'll take a very long time to charge full). There are so many applications where this kind of density is useful beyond just EVs.
IBM Lithium-Air battery research:
Next Big Future: Ultimate Specific Energy for Batteries, Ultracapacitors
Technology Review: IBM Invests in Battery Research
IBM Aims for a Battery Breakthrough 300 to 500 miles on a single charge
A consortium led by IBM hopes to develop lithium-air batteries that will power electric vehicles for 300 to 500 miles on a single charge
By Steve Hamm
"Eager to place itself at the forefront of technology considered crucial to transportation's future, Big Blue is throwing its weight behind batteries.
On June 23, IBM announced a multiyear effort to increase the performance of rechargeable batteries by a factor of 10. The aim is to design batteries that will make it possible for electric vehicles to travel 300 to 500 miles on a single charge, up from 50 to 100 miles currently. "We want to see if we can find a radically different battery technology," says Chandrasekhar "Spike" Narayan, who manages the Science & Technology Organization at IBM Research's Almaden lab in San Jose, Calif.
To do that, IBM (IBM) is leading a consortium that will create batteries using a combination of lithium and oxygen rather than the potentially combustible lithium-ion mix that now dominates advanced consumer electronics and early electric-vehicle batteries. The new batteries could be used to store energy in electric grids as well.
IBM is also eager to reclaim U.S. leadership in battery tech from Asia. While many of the original breakthroughs for the batteries that power today's laptop computers and cell phones happened in the U.S., those batteries now come primarily from Japan and Korea.
Industry leaders have called for just this kind of concerted effort amid concern that the U.S. will miss out on one of the most important technology shifts in history—the switch from gasoline to electricity as the primary power source for light vehicles. The worry is that the U.S. will trade its current dependency on the Middle East for oil with a new dependency on Asia for vehicle batteries. "We lost control of battery technology in the 1970s," laments Andy Grove, former chairman of chip giant Intel (INTC). "Battery technology will define the future, and if we don't act quickly it will go to China and Japan."
Battery as a commodity
With theoretical densities of 3050 Wh/kg I wonder if it even makes sense to build these batteries as rechargeable kind. A cheap (to manufacture) zinc-air battery should be lightweight enough to be easily swapped at a charging station (providing a convenient central location for recycling purposes). The battery then becomes a commodity (and a business opportunity for progressive energy companies). What drivers get out of this is all the benefits of EV (the "grin") at low upfront cost, reasonable operating expenses and "refueling" convenience. Plus, there is choice: those who produce their own energy and use EV primarily for commuting can invest in rechargeable batteries for everyday purposes, but still have access to "commodity" battery infrastructure for long-distance trips and those unexpected moments.
Will be watching this development closely ...
Max Energy density is looking very good. Any word on Power Density and Calender Life?
According to Battery Digest
In terms of calendar life:
Hence my hypothesis that focus of development are Lithium Air "power bricks" - disposable range-extenders to supplement internal car rechargeable battery, akin to the following device:
Not really ... With more and more "news" of vaporware (EEStor and hydrogen fuel cells being chief offenders) polluting the infosphere, I feel more and more distraction from areas where real progress is taking place.
Who cares about subtle machinations of EEStor hyping their fancy [mildly useful] barium-titanate powder, when a real industrial research organization is most positioned to bring us the ultimate battery to the table:
For a little perspective:
The linked paper describes the same kind of power brick that you mention above.
Interesting concept - a primary battery that would take a Roadster 50,000 miles (or am I missing something?)
Lithium air sounds really nice, and it has HUGE potential ... but there are still many kinks to work out. For example,
very low power density--
and doesn't like cold weather--
Now I'm sure these little issues can be resolved by keeping the batteries temperature-conditioned like the Roadster already does, and by paralleling with some Li-Ion batteries to supply the power while Li-Air batteries supply the energy.
I got 27K "ideal EPA range" with cell voltage of 3V.
40,000 g * 50 Ah /g * 3V = 6 MWh (quite a pack)
6 mWh * 244 miles / 54kWh = 27,111 miles.
Numbers make sense, given that such a pack would contain a lot of pure lithium metal, a very energy dense material, as anode.
Indeed a discharge rate of .1 A/g at 3V equals power density of just 30 W/kg -- 10x weaker than lithium ion. The paper does not specifically mention whether tests were conducted at atmospheric pressure, but perhaps increasing pressure could result in higher current flow.
Or trickle charge an ultra-capacitor, some of which have power density of 6KW/kg.
Why only 40kg?
I originally wanted to compare to weight-equivalent of Roadster's ESS. Shame on me for forgetting how many grams are in a kilogram :redface:
On second thought, 40 Kg is about the right weight for a "power-brick"; could probably go even lower to 20 Kg for 12K miles. Gosh, I hope they can make this technology work soon ...
Did you just invent an EV supercharger? :smile:
Seriously, though, to generate the ~190kW that the Roadster uses, you'd need over 6000 kg of batteries! You would, presumably, use some kind of power buffer (like an ultracap) to cover for bursts, but you'd still need the main battery to provide the long-haul average power. At 250Wh/mile and 60 m/h, you need 15kW sustained, which would still be 500kg of batteries at 30 W/kg. That's somewhat bigger than the Roadster's battery, and still kind of on the weak side.
That is, I think to be useful in cars, they need a big improvement in power density.
Well, I goofed on the order of magnitude (1 kg = 10^3 g), which means that .1 A/g translates into 300 W/kg, not 30. This level is presumably comparable to power output of lithium-ion cells currently employed in Roadster's ESS, so make that "power-brick" a 50 kg (instead of 40) for 15 kW on the go recharge of high power [low energy density] main traction battery. This looks like the game changer many were looking for (or did I goof with numbers somewhere again?)
Another way to look at it is that to deliver 190kW you'd need 633kg of the things.
633kg leads to 95MWh, which even with 'real world' power use is over 300,000 miles...
EDIT - so this felt a little too good to be true and here is why:
Having had time to read the linked article (as opposed to relying on the quotes above) I've seen there is some 'cheating' going on with the numbers. The energy density they are quoting is for the cathode only.
It felt slightly wrong given that the scaling up I did earlier based on this chart came out at ~50000 miles per charge, whereas the calculation from scratch came out at >300,000 miles.
Thinking about it, this can be verified by taking the 150mAh/g figure they have for Li-ion and working out Wh/kg, which comes out at 555Wh/kg. The alarm bells should be ringing, as the number for available batteries is under 200Wh/kg (2.775 times less).
So if you divide the 300,000 miles number by 2.775 (=108108) and then the ratio of the above pack to the Roadster's approximate mass of 18650 cells (633/320), you get 54,652 miles. Given some of the uncertainties in the information available, that's pretty close.
It's not clear, but that 2.775 divider also probably applies to the power density, so we are definitely back to the li-ion/capacitor based buffer to get peak power. But interestingly, it actually doesn't specify that 0.1A/g is the maximum discharge rate.
Still, this is an awesome achievement - I'd be interested to see the paper they presented in March for more details.
New lithium-air cell could make car recharging obsolete
Does "air" in Lithium-Air means it actively uses atmospheric air during its operation?
The oxygen component of it :smile:
More like "could make recharging impossible".
I have no interest in a battery that I can't charge cheaply at home. It negates one of the great benefits of an EV, low cost overnight home charging and never having to stop at a "gas" station or being tied into a single "fuel" source or provider.