Laurel, Maryland – Scientists at Johns Hopkins University have developed an inexpensive sensor that can warn of impending catastrophic failure in lithium-ion batteries.

The sensor is based on the researchers’ discovery of an intrinsic relationship between the internal temperature of lithium-ion cells and an easily-measured electrical parameter. The sensor is intended to detect thermal runaway, a self-perpetuating condition that occurs once a cell reaches a critical temperature and which can result in fire.

“An abnormally high internal cell temperature is a nearly universal manifestation of something going awry with the cell,” said Rengaswamy Srinivasan, a chemist and one of the inventors. “These changes can occur within seconds, leading to a potentially catastrophic event if corrective measures are not taken immediately. When things start to go wrong inside the cell, time is not on your side.”

The researchers discovered that a very small alternating current, when applied to a lithium-ion battery at specific frequencies, is modified by the cell in a way that is directly related to the temperature of the electrochemical interface between the battery’s electrodes and its electrolyte. The new sensor is able to detect potentially unsafe temperatures within the battery before surface-mounted temperature sensors are able to register any changes.

The university has applied for patents for the sensor and is pursuing licensing opportunities.

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