July 30, 2008
New Method Lowers Energy Cost Of Lithium Battery Manufacture
Materials science prof Arumugam Manthiram at the University of Texas at Austin might have made a big contribution toward our move toward electrically powered vehicles. A new way to make lithium iron phosphate batteries cuts costs by lowering the temperature needed to make them.
But it has proved difficult and expensive to manufacture lithium iron phosphate batteries, which cuts into potential cost savings over more conventional lithium-ion batteries. Typically, the materials are made in a process that takes hours and requires temperatures as high as 700 °C.
Hours at high temperatures suggest a large energy cost for lithium battery manufacture and a big energy debt that each electric car would start out with.
Manthiram's method involves mixing commercially available chemicals--lithium hydroxide, iron acetate, and phosphoric acid--in a solvent, and then subjecting this mixture to microwaves for five minutes, which heats the chemicals to about 300 °C. The process forms rod-shaped particles of lithium iron phosphate. The highest-performing particles are about 100 nanometers long and 25 nanometers wide. The small size is needed to allow lithium ions to move quickly in and out of the particles during charging and discharging of the battery.
What I'd like to know: How much energy does it take for A123Systems and other lithium battery makers to manufacture their batteries? The answer to that question would give us an idea of how many miles a hybrid, pluggable hybrid, or pure electric car would have to be driven before it would save more energy than it took to manufacture it originally.
Another issue is the coming shortage of Lithium in the world. According to some studies, the Lithium reserves in the world happen to be very limited, and before we build hundreds of millions of electric cars that use Lithium batteries, this rare metal will simply run out:
A few weeks ago, another commentator said that Lithium can also be extracted from sea water, and this is possible, but if it comes to that, then it almost certainly means another extra 15-20 years of delay before the world is in chaos.
But this means that we must also consider some other kinds of batteries like zinc-air batteries which are much more difficult to charge but have higher energy density than lithium, and so like ammunition magazines the zinc-air batteries can be swapped at gas stations instead of charging, simplifying the whole market actually, while these cars would have a range that exceeds 300 miles per charged battery.
It turns out that most of the Lithium reserves are in China, Chile and Argentina. So maybe South America and China should focus on lithium batteries, while the rest of the world should develop zinc-air and other batteries. Once extracted, Lithium can be recycled even after the battery has reached its normal life of 20 years, and so the lithium metal itself does get recycled into new batteries, and so this can continue forever. The only problem is the actual net shortage of lithium that will limit the number of batteries.
The following link shows that lithium is about 25% as abundant as both zinc and copper in the earth's crust.
Now clearly that doesn't say anything about the how difficult is may be to mine or process, but if its even remotely like copper, we certainly won't be running out soon.
Why is it a worry as to how much energy is spent manufacturing batteries? I don't think we have a problem with enough energy, it is a problem with having enough liquid fuel for transportation. As long as they are not using oil to run their factory, it is not a big deal.
"the Lithium reserves in the world happen to be very limited"
One word: ASTEROIDS
High process temps are expensive because of special handling, holding materials, delays heating and cooling - energy costs are likely to be not especially important. Good insulation is all that's needed - energy should be a big input where it's actually consumed in an endothermic reaction, as you'd find in, say, aluminum smelting.