Here are the technical details: The idea of a conventional battery is that two solid electrodes are immersed in a fluid-like substance (they may be dangled in there, or sandwiched in a complex multi-layered structure, but the design is the same) that allows for flow of chemicals–when charged, the battery chemistry enables the liquid to huddle up to the solid electrodes so electrons flow out of the battery and into the circuitry you’re using. To charge it up, you push electrons back in to the battery, and the internal chemistry re-arranges itself ready to be discharged.
In MIT’s system, the electrodes and battery fluid (electrolyte) are still separate, but they’re all mingled up as a kind of sludgy liquid. The electrodes are made of tiny particles suspended in liquid electrolyte, and to discharge it you pump the fluid through a special kind of filter–thus allowing electrons to flow out of your battery. It’s called a semi-solid flow cell, and though it’s not brand new tech,
no one’s been able to achieve the kind of useful high energy density MIT
Sound complicated? It is. But battery science notwithstanding, here’s what you need to know: The tech allows for less bulky designs than is usually possible, meaning EV components–battery, electronics, and motors–could be more easily dropped into conventional car designs. Picture cramming a useful EV battery into a car the size of a Smart, and you’ll see why this is useful. Better still, because the “battery” exists as two systems with one to store energy, and the extraction system designed to discharge it, it’s easy to remove the “storage” part to replace it. That could mean easily swapping out a charged fuel “tank” in minutes at a filling station, but it could also mean pumping out “spent” fuel, and replacing it with new fully charged battery chemistry. That spent fuel could be charged up at the station, and then injected into the next nearly empty battery that drove up.
Moments to charge your EV instead of hours: Sounds so fabulously useful, and a freakishly brilliant way to tackle the limited range that beleaguers EV design. No wonder the science team is dubbing their odd new battery sludge “Cambridge Crude.”
[Image: Flickr user livenature]