Chemical Current Source Express Diagnostics Using Noise Spectroscopy on the Example of Lithium-Thionyl Chloride Battery

Abstract

Lithium-thionyl chloride battery voltage is practically not changing during the discharge process and drops sharply being completely discharged. In this regard, the problem of non-destructive quality control of the chemical current sources (first of all, the discharge degree) before installation thereof in the equipment becomes of particular importance. Microcalorimetric studies make it possible to rather correctly determine the current source internal self-discharge rate, predict the LCCS shelf life and its performance term. However, the heat release absolute value in current sources with sufficient storability, i.e., with low self-discharge, is very small; therefore, it is necessary to use sensitive, stationary and large-sized equipment. This makes such diagnostics impossible when operating in the stand-alone conditions. The impedance spectroscopy method could be proposed to solve this problem. However, satisfactory results are only obtained in the 0--70 % residual capacitance range. Determination of residual capacitance in the 70--100 % range appears to be rather difficult due to the absence of noticeable alteration in the informative parameter within the limits of its absolute deviation from the mean value. In this regard, it looks advisable to use noise spectroscopy as a physically independent method in diagnosing the state of chemical current sources to expand the residual capacitance diagnostics range to the 70--100 % domain, as well as to increase reliability of the chemical current source diagnostic estimate in the range of 50--70 %. Results of the electrochemical noise measurement analysis confirm promising application of the noise spectroscopy method in estimating current state of the primary chemical current sources in their low discharge domains