Comments on: there is no better battery

By: Tesla Roadster the Next Generation Sports Car

Tesla Roadster the Next Generation Sports Car — Wed, 18 Nov 2009 07:29:10 +0000

Tesla Roadster the Next Generation Sports Car…

This is the greatest car ever. Can you imagine to ride all day with the pleasure of Porsche GT3, and to pay about $10 for this. It is just amazing!!!…

By: Anonymous

Anonymous — Mon, 29 Sep 2008 16:19:06 +0000

Fuel cells seem the most promising in the short term, the main problem is cost but someone just invented a fuel cell replacing the platinum with GoreTex, of all things.
The guy with the flywheel design was building his flywheels out of carbon fiber. A failure resulted in the wheel bursting into small easily-contained fibers. Don’t know about the “bouncing down the road” problem but it seems likely that the wheels would burst if they hit the container walls.
Ultimate solution is probably superconductors.
Then again, if you use algae-based biofuel, internal combustion engines are just fine.

By: Tom

Tom — Mon, 29 Sep 2008 15:18:28 +0000

Rosco: I would suggest you remain skeptical of any battery technology that’s promising a doubling or quadrupling of performance. I hope it works out, but am not particularly optimistic.
Johann and Goishin: supercaps are cool, but so far they can’t store nearly as much energy as an electrochemical cell of the same size. Maybe that’ll change, but again, it would be a mistake to assume that it will.
As for flywheels — yes, they’re great for storing energy. They have to be extremely massive to do so, though, which means it takes a lot of energy to move them around. And what happens in a crash? Imagine a cascading failure of massive flywheels hurtling down the freeway, setting each other off. It would be horrific. Flywheels aren’t really viable for vehicles smaller than a tank. Finally, Zn/air isn’t a rechargeable chemistry (I think you’re also overstating its energy density considerably, most likely due to someone quoting an implausible energy consumption for the laptop you allude to).
Josh: actually, it’s both price AND capability that need improving. Tesla clearly designed their roadster without much concern for cost, but the batteries they use still deliver a fairly anemic range. By emphasizing the car’s impressive acceleration, they seem to have managed to imply that electric cars can be awesome, it’s just that it costs too much to make them so. But designing an electric vehicle with great pickup is actually really easy — it’s range that’s the crucial problem. So it’s not just a question of cost. Cheaper batteries would be great, and would let us do more things. But we really do need energy storage technologies with greater capacity, too.

By: goishin

goishin — Sun, 28 Sep 2008 22:32:04 +0000

You’re right about theoretical limits on batteries. The chemistry involved has been quite well known for a long time. But you’re neglecting “other” technologies than purely chemical.
I remember reading about a guy who was storing energy in a rotating electromagnetic flywheel. Put energy in by speeding up the flywheel, and take energy out by turning it into a generator. The main problem is finding a suitable flywheel that doesn’t explode at the tremendous speeds it was spinning at.
Or how about the ultra-capacitors that I read about that MIT was working on? Takes seconds to charge and can hold energy at densities greater by several magnitudes of conventional batteries.
Or even the zinc-air batteries? Powers a laptop for twenty hours in one charge.
The point is this; just because we believe one avenue of research won’t prove fruitful just because twenty or thirty years ago researchers said it wouldn’t work doesn’t mean further down the road we won’t be able to overcome that stumbling block.

By: kettal

kettal — Sun, 28 Sep 2008 22:26:02 +0000

The solution is not cars at all. The answer is electrified trains baby!

By: Josh Yelon

Josh Yelon — Sun, 28 Sep 2008 22:08:01 +0000

But we don’t really need the batteries to be better, we need them to be cheaper. So we don’t need better battery technology, we need better battery-manufacturing technology.

By: johann

johann — Sun, 28 Sep 2008 21:40:35 +0000

why does “battery” have to mean electrochemical? what about supercaps?

By: Rosco Fropper

Rosco Fropper — Sun, 28 Sep 2008 20:10:43 +0000

I disagree with the assessment that sufficiently good batteries don’t exist. The key question is energy density – the amount of kw.hours you can store in a kilogram.
Modern batteries have hit the densities required. You need about 20 kw of output for four hours to make a car with a normal range. That’s an 80 kw.hr battery. The existing Tesla Roadster has a smaller pack, 53 kw.hrs.
A LiIon battery has a density of 0.16 kw.hrs/kg so your battery for the car above has to weigh 500 kg. That’s heavy, but not insurmountably so, once you get rid of a gas engine and gas tank.
If you are willing to have a commuter car with half the range of a normal car (recharge it every night), you can halve the weight and expense of the batteries. This would be fine as a second car.
The lithium sulfur battery is projected to have an energy density two to four times higher, so the battery mass will be just a couple of hundred of kg for a normal car. Just 15% of the car’s mass would be battery.
The issue is battery expense, not the technology. Make existing batteries cheaper, and electric cars will be better than present day gas cars.

By: G.R.L. Cowan, H2 energy fan 'til ~1996

G.R.L. Cowan, H2 energy fan 'til ~1996 — Sat, 30 Aug 2008 20:21:03 +0000

Batteries can oxidize a wide range of fuels because they retain the ash. It is possible for internal combustion systems to do this too by a judicious choice of fuel. If the ash can leave the combustor, but then be cached in a compact cache in a waste cache bin, it can work better than a battery.

By: Tom

Tom — Fri, 29 Aug 2008 18:36:56 +0000

Thanks for the kind words, Fred. I agree completely that the usefulness of battery-related prizes or non-market incentives is regularly overstated. I didn't discuss it here because I did so earlier -- I probably should've included a link to that post in this entry.