Increasing Electric Car Battery Performance
September 23, 2009 by John Messina
(PhysOrg.com) -- Researchers have found that by replacing conventional graphite electrodes with silicon nanotube electrodes, lithium-ion batteries can store 10 times more charge.
The research was performed at the Stanford University and Hanyang University in Ansan, Korea. The joint effort is between the Universities and LG Chem, a Korean company, who makes lithium ion batteries for the Chevy Volt.
In a conventional Hybrid Car, using today's technology, a lithium-ion battery charge only last 30 minutes.
A battery is charged by the movement of lithium ions from the cathode to the anode. By replacing the graphite electrode with silicon, much more energy can be stored because the silicon absorbs larger amounts of lithium in the charging process.
Because silicon anodes absorb up to 10 times more lithium by weight, its volume also increase by 4 times. This can be a disadvantage as the material becomes brittle and can crack after the battery has been charged and discharged a few times. By developing a nanostructured silicon design, researchers have found that the silicon material can better withstand the stress.
There are some major challenges ahead before the silicon nanotube electrodes can be used in electric car batteries. One of the problems is getting back all the energy from the silicon anode after the battery has been charged. The battery must be able to be charged hundreds or thousands of times before this type of battery can be used in electric cars. As of today this has not yet be shown.
Electric car batteries, incorporating silicon nanotube electrodes, could be on the market in three years. It's too early to determine whether this new technology will add to the cost of lithium batteries.
More information: Silicon Nanotube Battery Anodes; Nano Letters, DOI: 10.1021/nl902058c
Via: Technology Review
© 2009 PhysOrg.com
Nov 19, 2008 |
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The only thing it ran was a small lcd clock,,,it
exploded !! Oh yeah, batteries NOT.
For plug-in customers willing to pay a premium for bleeding edge performance, leasing models should accommodate any experimental battery requiring more frequent replacement.
Far more likely that it failed for one of the same reasons the vast majority of "breakthroughs" we read about every day fail -- production scalability, high cost, intractable quality control problems, product safety and longevity, or just plain hype that far exceeded reality.
One thing to consider, though, is catching something in the early phases is much easier to stop. Offer a few people a couple million a piece to forget about it. Happens a lot in all different places.
Here's an example: Los Angeles had an excellent subway system at the beginning of the 20th century. The auto industry decided it wanted to sell cars there and after world war II was able to. They purchased the subway (under whatever pretense; it doesn't matter) and just let it sit there. Effectively forcing people to buy cars (or take the bus).
Now think about what large companies have the ability to do.
I'm not saying that this battery thing was a conspiracy, but don't dismiss it without digging deeper.
and there was likely nothing special about Tesla's burial by Westinghouse either . . . ?
We don't really need breakthroughs as we already have batteries that work fine. The biggest problems with our racers is keeping the axles from snapping. Tesla had to get rid of their 2 speed transmission because it kept breaking.
We have motors/controllers that hit 600kw or about 800hp and batteries that put that out.
The Killacycle EV MC does the 1/4 mile in 7.9sec at 168mph. Do we really need more performance?
What we need is car companies to build them. BTW oil companies do stiffle EV's. Chevron bought the NiMh patents and stopped Panasonic/ Toyota and everyone else from building EV size batteries.
This report seems to be covering some of the earliest research in this area. The initial nanotube technology did not retain this capacity after just a few charge cycles, leading Dr. Cui to explore alternate nanowire chemistries. One that was recently published was regarding “core shell” nanowires, wherein there’s a crystalline nanowire core to conduct the electrons and an amorphous surface, which has better stability. This comes at the cost of only a 3x improvement in energy density over graphite. At this point in the research, they’re already up to 90% capacity retention after 100 cycles.
Even a applicable 3x improvement would be a real game changer, making electric cars more competitive in terms of cost, travel range and battery weight effect related fuel efficiency.