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Method and apparatus for indicating electric charge remaining in batteries based on electrode weight and center of gravity

United States Patent

*** EXPIRED ***
December 3, 1996
View the Complete Patent at the US Patent & Trademark Office
Idaho National Laboratory - Visit the Technology Transfer and Commercialization Office Website
In most electrochemical batteries which generate electricity through the reaction of a battery electrode with an electrolyte solution, the chemical composition, and thus the weight and density, of the electrode changes as the battery discharges. The invention measures a parameter of the battery which changes as the weight of the electrode changes as the battery discharges and relates that parameter to the value of the parameter when the battery is fully charged and when the battery is functionally discharged to determine the state-of-charge of the battery at the time the parameter is measured. In one embodiment, the weight of a battery electrode or electrode unit is measured to determine the state-of-charge. In other embodiments, where a battery electrode is located away from the geometrical center of the battery, the position of the center of gravity of the battery or shift in the position of the center of gravity of the battery is measured (the position of the center of gravity changes with the change in weight of the electrode) and indicates the state-of-charge of the battery.
Rouhani; S. Zia (Idaho Falls, ID)
Lockheed Idaho Technologies Company (Idaho Falls, ID)
08/ 289,164
August 11, 1994
CONTRACTUAL ORIGIN OF THE INVENTION The United States Government has rights in this invention pursuant to Contract No. DE-AC07-76ID01570 between the United States Department of Energy and EG&G Idaho, Inc.