06037777 is referenced by 154 patents and cites 11 patents.

A device includes a microprocessor or microcontroller and measures real and imaginary parts of complex immittance of a cell or battery at n discrete frequencies, where n is an integer number equal to or greater than 2. The device determines cell/battery properties by evaluating components of an equivalent circuit model comprising 2n frequency-independent elements. Equating real and imaginary parts of measured immittance to values appropriate to the model at the n measurement frequencies defines a system of 2n nonlinear equations. Introducing 2n intermediate variables permits solving these equations and leads to values for the 2n model elements. A table of element values contains virtually the same information as the spectrum of complex immittance over a wide frequency range but provides this information in a more concise form that is easier to store, analyze, and manipulate. Thus, the 2n element values may themselves comprise the desired result. If desired, however, a predetermined relationship between one or more of the elements and an additional electrical, chemical, or physical property of the cell/battery may be further invoked to determine the additional property.

Method and apparatus for determining battery properties from complex impedance/admittance
Application Number
Publication Number
Application Date
September 11, 1998
Publication Date
March 14, 2000
Keith S Champlin
5437 Elliot Ave. South, Minneapolis, 55417
Westman Champlin & Kelly P A
G01N 27/416
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