Abstract: The present invention teaches providing a sensor capable of detecting organic vapors in close proximity to the li-ion battery, these organic vapors being reliable indicators of battery troubles before the battery troubles even manifest themselves. The sensor may initiate (actuate) various responses such as alarm indicators of various types, changing the mode of usage of the battery or even taking the battery off-line. The organic vapors may be any of a wide range of types as a degrading li-ion battery may emit any one of a wide range of different organic compounds. The invention may also be used with batteries immersed in fluids. Numerous types of li-ion battery may use the device, which is much faster than a post-failure smoke detection.

Abstract: A Li-Ion monitor includes a combustible vapor sensor positioned in air flow communication with the exterior of a hermetically sealed Li-Ion battery cell to detect combustible vapor escaping therefrom. Detection of the vapor indicates that an overheat or fire situation may be impending. Where the Li-Ion battery cell is immersed in liquid, the combustible vapor sensor is in air flow communication with a surface of the liquid. Alternatively, or additionally, an electrolyte sensor can be immersed in or otherwise in fluid flow communication with the liquid to detect electrolyte escaping from the cell which electrolyte would, if exposed to air, become a combustible vapor.