By Andy Choi
Scientists have developed a less-expensive sensor, which can alert the imminent appalling failure in the lithium-ion cells used in the electric and hybrid vehicles, at the Applied Physics Laboratory (APL) of Johns Hopkins University in Laurel.
The sensor is designed on the basis of an intrinsic relationship between the measured electrical parameter and internal temperature of the lithium-ion batteries. The cells ensure increased energy density to power millions of user electronic systems. Due to thermal runaway, the failures and fires of the battery cells in mobile phones, laptops and electric vehicles have been reported in the media.
Rengaswamy Srinivasan, a chemist in Research and Exploratory Development Department of APL, stated that an abnormally increased internal temperature of the battery is the universal sign of some catastrophic events, which can take place in seconds without the initiation of any corrective measures.
Srinivasan with the other scientists has discovered that when the lithium-ion battery is supplied with a very small alternating current at particular frequencies, the current is modified by the battery with respect to the temperature of the protective layers between the electrolyte and electrodes and it is the condition in these layers that result in failure and this finding enables identification of possible dangers before the surface-mounted sensors. The sensor is electrically terminated at the positive and negative leads of the battery so that it is powered for its operation. A single sensor can be used to sense several batteries in a package by employing a multiplexing circuitry.