Lithium-air batteries

[Serge]

the section on "Energy Storage" contains this metal-air project: (Not sure if that means "Lithium-Air", but promises a comparable energy density.)

I touched upon this grant in Candidates, Loans and Bailout thread. These are Zinc-Air batteries and research is lead by Cody Friesen of ASU (and co-founder of Fluidic Energy). Hopefully we'll see Lithium Air research covered in the next iteration: Berkeley-based PolyPlus is a good candidate and IBM of course.

[Norbert]

These are Zinc-Air batteries and research is lead by Cody Friesen of ASU (and co-founder of Fluidic Energy).

This would probably mean that "recharging" implies physically replacing the Zinc, which seems to mean that their usefulness is more for power plants, than for EVs.

Hopefully we'll see Lithium Air research covered in the next iteration: Berkeley-based PolyPlus is a good candidate and IBM of course.

It seems to be difficult to get an idea of the chances of success for the Lithium-Air projects (even for the researchers themselves). It is a bit surprising that there seem to be so few research projects for Lithium Air. According to everything one reads about it, it would be a huge "game-changer". IBM seems to be in some kind of evaluation phase of pre-researching, instead of immediately starting a full scale effort which would match its immense potential.

[Serge]

This would probably mean that "recharging" implies physically replacing the Zinc, which seems to mean that their usefulness is more for power plants, than for EVs.

AFAIK, this property was common to all metal-air chemistries for a while making such devices more "fuel cells" than "batteries" and limiting practicality (the infrastructure dilemma). However, very recently breakthroughs started to happen. In Europe ReVolt and BASF have joined forces this summer to commercialize electrically rechargeable Zinc-Air battery ReVolt developed. The rechargeability approach looks similar to ASU's: porous cathode and liquid electrolyte are used, but ReVolt/BASF seem to be further ahead.

It seems to be difficult to get an idea of the chances of success for the Lithium-Air projects (even for the researchers themselves). It is a bit surprising that there seem to be so few research projects for Lithium Air. According to everything one reads about it, it would be a huge "game-changer". IBM seems to be in some kind of evaluation phase of pre-researching, instead of immediately starting a full scale effort which would match its immense potential.

From what I read on the topic making even a primary (non-rechargeable) Lithium Air battery operate outside of lab environment is very difficult due to metal Lithium's chemically active nature. PolyPlus developed protective coating for Lithium metal anode making a step in commercialization direction for primary type. Secondary battery with good cycle life is even more challenging, but AIST in Japan has had some progress in that area.

[widodh]

Hi,

While I'm waiting for my Model S, I've been reading around about batteries and I found that the Model S is expected to have around 250Wh/KG (I'm Dutch, so I use KG's )

After some searching I found this: http://en.wikipedia.org/wiki/Lithium_air_battery

The theoretical density of Li/O2 is 11140Wh per KG.

If I understand it correctly, a 8KG battery would then provide 84kWh of energy, the same as the Model S now.

Well, that seems to good to be true, so what is the catch here? I know Lithium-Air is still in the lab and currently it can't be recharged, but there must be something else here?

On Wikipedia I found that the current batteries can have around 250Wh/KG, just like the Model S will have.

Now, I'm no battery expert at all, but if a Lithium-Air battery with such density could exist, what kind of problems would we run into?
* It can't absorb energy that fast?
* It can discharge fast enough?

Again, it seems good to be true, so I'm searching for the cavecat here

[TEG]

Just went looking for downsides, and found this (but claims it is being solved):

http://slashdot.org/story/09/06/26/1...Energy-Density

...Previous efforts to make lithium {air} batteries have been stymied by the sensitivity of lithium to water in the air...

Also:

The problem is the recharging step, ie, making it a battery instead of a fuel cell. Splitting zinc oxide to get relatively pure zinc back, all within the original container, remains an unsolved problem, in practice. These lithium devices will face the same problem: how do you use electricity to efficiently split lithium oxides to get lithium and oxygen again?

So, I guess one has to investigate charging efficiency so see how much of the current you put in actually gets stored in the battery.

[TEG]

More:
http://www.good.is/post/building-a-better-battery/

...One major barrier remains: When the oxygen reacts with the electrolyte to form ions, it also creates a solid that can gunk up the air intake, blocking the battery's function. Researchers are searching for an electrolyte that will produce the necessary ions but avoid the formation of this solid...

[widodh]

Ah indeed, there you have it. Other then Lithium-IOn there aren't any real alternatives right now? We'll have to keep howling these large batteries around for the coming years.

[TEG]

Ah indeed, there you have it. Other then Lithium-IOn there aren't any real alternatives right now? We'll have to keep howling these large batteries around for the coming years.

Over the past few years there were so many announcements of things like ultracap breakthroughs, NiMH improvements, even massive improvements to lead/acid. I wouldn't say that Li-Ion is absolutely the only possible solution, but so far it seems to be the technology of choice among all the current generation of EVs.

[widodh]

It's all about the Wh/KG, the less the battery weighs, the less the cars weighs, the less energy you need to move the car. That would result in a smaller (in Whr's) battery pack.

Ultracaps are one of the things I believe could be useful, even in conjunction with a regular battery, they could provide the boost of power a EV needs when accelerating.

But it seems that LiO2 is still far away

[Lloyd]

I beleive that Ultracaps are what your regen should go into first, once filled, then the battery. It would save the battery from all of the continuous charging and discharging which a capacitor is made to do. If this design is used you should have. 1. Longer battery life 2. No annoyance of not have regen available at times. Of course this involves a more complex controller to orchestrate all of this, and more $$$$