Batteries Used in Electric Cars to Get Safe with the Addition of Special Molecules in Electrolyte
By August 26th, 2009Wednesday, August 26, 2009 8:42 on
The molecule, developed by researchers Zonghai Chen and Khalil Amine at Argonne National Laboratory, is being tested as an additive in the electrolyte of lithium batteries to keep cell voltage from going too high.
The batteries used in electric and hybrid vehicles typically consist of 200 to 400 small cells, strung together into one powerful whole. Individual cells sometimes overcharge, emitting heat when they reach too high a voltage and pushing neighboring cells past the breaking point to set off a runaway thermal reaction.
Because electric and hybrid vehicles are constantly discharging and recharging during normal driving, overcharging problems are not confined to the garage but pose a real operational hazard.
In the lab, Amine and Chen discovered they could make a molecule based on boron and fluorine and add a tiny amount of it to each cell to control charging. When the cell exceeds the safe voltage level, Amine explained, the molecule picks up electrons and keeps the cell charge from going up.
Currently, expensive electronic controls are used to regulate each individual cell in a battery and shut it down if the voltage gets too high. But the control systems are expensive, making up as much as 20 percent of a battery’s cost, and the electronics are prone to failing.
Original Source: NYTimes
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