Nobody needs an introduction to electric cars, hybrid cars or the Lithium-ion pack. We are all a witness to the race for such green cars, whether in pure form or a later conversion to it through kits. The truth is– while such green move is laudable, yet by taking it, we are also putting our lives at risk.
Due to its lightweight and size, lithium batteries have commonly been used in Laptops and cell phones. Sometimes, when massive amount of energy is stored in a small space it tends to burst into flames violently. Since both the fuel and the oxidizer are bundled into the battery, they can’t be smothered like common fires, says Dan Doughty, who manages lithium-ion battery testing at Sandia National Laboratories in Albuquerque, NM.
Doughty adds further:
Such problems are rare, occurring in one of ten million cells in laptops and other electronics. If there are 7,000 cells, and there’s one in ten million failures, you do the math in terms of how many vehicles are going to have a cell problem.
According to the U.S. Consumer Products Safety Commission, more than 300 lithium-ion battery-overheating accidents occurred from 2003 to 2005. Therefore, the most challenging safety issue related to such batteries are-how to prevent overcharging, overheating, and damage in an accident. Sometimes, these accidents can get so out of hand that it causes ‘thermal runaway’-an uncontrollable chemical reaction where temperature escalate to melt even aluminum plus causes batteries to explode.
In Tesla’s wonder car, all of the 7,000 batteries have been isolated and protected with its own steel case. Not only that, an electronically controlled liquid cooling system, overcharging protection is also provided along with an encasement for the entire system. Mark Verbrugge, a battery expert at GM’s Research and Development center in Warren, MI, still has a point to worry. He says:
The one thing that really worries OEMs is you can’t control poor-quality manufacturing as it relates to safety. For example, if two electrodes touch because it’s poorly manufactured, you’ve got a problem.
Doughty adds:
If there’s a flaw in the manufacturing, and it has an internal short circuit, there’s nothing you’re going to do externally to interrupt that reaction.
In contrast to what Eberhard believes, bad battery can be a big problem even if it comes in a steel case and a liquid cooling system to carry away the excess heat. During test, Doughty saw violent explosions with the strength to burst a steel case. If the liquid cooling fails, a single battery could cause neighboring batteries to overheat, causing chain explosion.
Via: Technology Review
