More battery power news has come out recently, this time about work being carried out at MIT and an apparent breakthrough in the design of Lithium batteries. This could be really important as whilst Lithium batteries are far from ideal in terms of environmental friendliness (they are toxic), they are the best mobile energy storage device we currently have in terms of energy density and cost. Importantly, they are also now a well understood and quite mature technology (let’s hope the days of exploding laptop batteries are behind us!).
What’s being reported is that a group of chemists at MIT have come up with a new technology to change the surface crystallization in a typical lithium cell. It’s all pretty high level chemist stuff, but the news is that they can use existing lithium chemistry and change it to use this new electrode preparation. With the change made they claim to then be able to fully charge and discharge the battery in a few seconds.
Rapid charge and discharge is an important feature of ultra capacitors which I mentioned in a post here a few weeks ago and it’s what would make any battery especially useful for electrically powered vehicles. In a vehicle you need large amounts of energy delivered very quickly while accelerating and of course ideally very quick re-charging if your batteries run out during a journey. Lithium batteries environmental and lifetime downsides don’t make them the ideal choice for electric vehicles, but it’s all we’ve got right now so if this technology comes out of the lab it would be a massive step forward until a better solution is found.
Of course this is forgetting all the other devices that currently use lithium batteries. Being able to charge you laptop, mobile phone etc in a few seconds would be marvelous and no doubt new devices will appear that previously weren’t practical. Will people in years to come be amazed to learn that we used to have to charge our mobile phones overnight?!
Unlike ultra capacitors this innovation doesn’t rely on increasing the voltage stored. Electrical power is basically (voltage x current), and this innovation simply allows the current to be increased to achieve the much faster charging and discharging. This makes things nice and simple for the electronic designer as there don’t need to be nasty high voltages to deal with.
The power rate of a traditional lithium ion cell (the rate at which you’re able to draw power from it) is between 0.5 and 2 kilowatts per kilogram. In MIT’s test cells, using their modified lithium ion phosphate electrode, they’re able to get 170 kilowatts per kilogram – thats an increase from 2 to 170!
As tends to be the case with these announcements its early days. However producers have already licensed the technology so as this is an field that is already understood with large manufacturing facilities in place maybe this is something we could be using in just two or three years time…?
