UPDATE: Scientist casts doubt on "30 year battery"

 

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By Stuart Turton

Posted on 2 Oct 2007 at 12:40

A scientist from University College London (UCL) has cast doubt on reports that US Air Force scientists are close to releasing a battery that could power a laptop for 30 years without being recharged.

The batteries are supposedly based on existing betavoltaic technology which uses decaying radioisotopes as an energy source, according to a report on Next Energy News.

However, Dr Tony Harker, a physicist at UCL is unsure of the claims, "The sort of power density I have seen suggested for these betavoltaics is a few tens to a few hundreds of microwatts per cubic centimeter," he tells PC Pro.

"A typical mobile phone battery supplies one or two watts, so it's clear that this technology is not a replacement for present batteries. What it can do is trickle charge batteries which only need to run at full power in short bursts.

"A lithium ion battery has a power density of more than a watt per cubic centimetre. If you want electric power capable of fueling an electrical device like a laptop for years, I don't think this is it," he says.

"I suspect that tritium is actually the energy source, and that the reaction being exploited is the decay of tritium to Helium-3," he adds.

"If it really is tritium that is used, the lifetime claimed is usually five to 15 years: 30 years sounds a bit optimistic. The half-life of tritium is 12.3 years, so after 30 years the power would be less than one fifth of its initial level."

The 30 year battery follows Sony's sugar battery research as companies seek to move away from "fundamentally-flawed" lithium-ion power sources.