We have seen recently some new breakthroughs in improving the lithium-ion (Li-ion) battery. These developments combine the use of nanomaterials and nano-scale microscopy tools like the transmission electron microscope (TEM) to find ways of someday creating better Li-ion batteries.
Improvements to Li-ion batteries bodes well for powering small gadgets like our cell phones and MP3 players, but when it comes to powering electric cars the picture becomes a little different. By some accounts, Li-ion batteries’ energy density will only get about two times better than it is today, leaving one to ponder whether perfecting the Li-ion battery is time and money well spent in developing a way to power a vehicle that is competitive with the fossil-fuel-powered variety.
However, now it seems a lot of time and money is being invested in the hope that Li-ion battery technology will be the solution. According to Industry Week’s Nanopulse column last week, nano-enabled Li-ion batteries produced by companies like A123Systems are not only powering the electric vehicles of today but are also powering an economic recovery in the US as new plants are being built to capture back market share of Li-ion battery production from Asia.
Scott Rickert in his column provides some prices per kWh that show a dramatic drop in pricing fueled in large part by greater production than ever before. But price is really only one of the metrics that will determine whether Li-ion batteries can fuel an electric vehicle age. There is one other metric that I think supercedes all others and I like to describe it as the “will-it-work” metric.
According to that metric, barring any unforeseen development, Li-ion batteries are never going to get close to the 1000Wh/kg needed for batteries to compete with the internal combustion engine in powering vehicles. If they do improve to about twice that of where they are today, Li-ion battery will be maxed out at around 400Wh/kg.
Over at a publication called Alt Energy Stocks, they have a pretty alarming interpretation of a recent presentation given by Energy Secretary Steven Chu at the United Nations Climate Change Conference in Cancun. According to the article, penned by John Petersen, it seemed as though Secretary Chu was suggesting, at least tacitly, that “that lithium-ion batteries are a dead-end electric drive technology”.
Petersen comes to this interpretation after hearing the following remarks that come about 25 minutes into the video above.
"And what would it take to be competitive? It will take a battery, first that can last for 15 years of deep discharges. You need about five as a minimum, but really six- or seven-times higher storage capacity and you need to bring the price down by about a factor of three. And then all of a sudden you have a comparably performing car; let's say a mid-sized car which has a comparable acceleration and a comparable range."
Now, how soon will that be? Well, we don't know, but the Department of Energy is supporting a number of very innovative approaches to batteries and its not like its 10 years off in the future, in my opinion. It might be five years off in the future. It's soon. Meanwhile the batteries, the ones we have now, will drop by a factor of two within a couple of years and they're gonna get better. But if you get to this point, then it just becomes something that's automatic and I think the public will really go for that."
While Secretary Chu is saying this, there was a slide showing what a rechargeable battery will need to be able to do to compete with fossil fuels: "A rechargeable battery that can last for 5,000 deep discharges, 6-7 x higher storage capacity (3.6 Mj/kg = 1,000 Wh) at 3x lower price will be competitive with internal combustion engines (400 - 500 mile range)."
The Li-ion battery just does not look to be the solution to these requirements. And I am simply not swayed by the examples of the Chevy Volt that can only manage about 40 miles before it starts using its gas tank, and it seems that estimates that the Tesla can go 200 miles without a recharge seem to be exaggerated for anyone that has watch the UK show Top Gear.
The point here is that Li-ion battery may be the solution for powering hand-held gadgets but we may need to look somewhere else if we want to get serious about replacing the internal combustion engine in our vehicles.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.