Bendy batteries: the MIT Slimcell

Power-weight ratio is a catchphrase of all motor enthusiasts from Formula 1 to dragster racing. Expressed in Watts per kilogram it is everything in the complex world of batteries. Enter the bendy battery, as thin as a crisp packet but packing a real charge. Professor Donald Sadoway and his team at Massachusetts Institute of Technology are pushing at the boundaries of battery technology with their lithium ion Slimcell. A unique feature of this ultra-thin laminate is the flexible polymer (perspex) electrolyte capable of storing 250Wh/kg. That’s seven times more than a conventional lead-acid battery and twice the capacity of lithium ion batteries in mobile phones and laptops, both using heavier liquid electrolytes. When can we get our hands on Slimcells? Sadly not for a while, until battery manufacturers pay back their capital investment in the current technology and MIT sort out the patents… [©Alastair Fuad-Luke, 2005]