State of Battery Health Test Set, Employing Time Domain Spectroscopic Techniques

Time Domain Spectroscopy (TDS) is a precision metrology technique which allows the condition of an electrochemical cell or battery to be quantitatively evaluated in real time, obviating the protracted data collection times associated with the more familiar Frequency Response Analysis Method. In the FRA method, the cell's responses to a sequence of sinusoidal excitations are used to estimate the parameter values of an electric circuit model, which can then be used to simulate the behavior of the cell. In contract, a well definded non-sinusoidal excitation is used for TDS measurement, and the resulting response is evaluated using pattern recognition algorithms to immediately assess the condition and capacity of the cell under test. The TDS mehtod has been demonstrated to be effective for determining the condition and capacity of cells of several secondary battery chemistries, including lead-acid, nickel-cadmium, and most recently, lithium-ion types. Preliminary results also indicate that the 'state-of-life' of these cell may be estimated. TDS Technologies, Inc., proposes to extend this technique for use with a variety of primary and secondary cell types, including lithium sulfer dioxide units and others.