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Method, system and computer-readable media for measuring impedance of an energy storage device

United States Patent

January 26, 2016
View the Complete Patent at the US Patent & Trademark Office
Idaho National Laboratory - Visit the Technology Transfer and Commercialization Office Website
Method and Apparatus for In-Situ Real Time Characterization of Energy Storage and Energy Conversion Devices
Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. A time profile of this sampled signal has a duration that is a few periods of the lowest frequency. A voltage response of the battery, average deleted, is an impedance of the battery in a time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time profile by rectifying relative to sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.
Morrison; John L. (Butte, MT), Morrison; William H. (Butte, MT), Christophersen; Jon P. (Idaho Falls, ID), Motloch; Chester G. (Idaho Falls, ID)
Battelle Energy Alliance, LLC (Idaho Falls, ID), Qualtech Systems, Inc. (East Hartford, CT), Montana Tech of the University of Montana (Butte, MT)
13/ 438,741
April 3, 2012
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT The invention was made with government support under Grant No. NNA05AC24C awarded by the National Aeronautics and Space Administration, and with government support under Contract No. DE-AC07-051D14517 awarded by the United States Department of Energy. The government has certain rights in this invention.