Investigation of the Coulombic Efficiency and the Superior Differential Capacity Degradation Analysis

The Coulombic efficiency (CE) measurement is a promising method to quickly determine the potential lifetime of a battery cell. It will be demonstrated that high-precision measurements are required to determine the CE of modern cells. For this purpose, a comparison of our in-house developed precision hardware and two commercially available hardwares is performed. Furthermore, it is shown by means of a model that the CE can be misleading when it comes to the determination of cell aging. As a better alternative, the (conventional) differential capacity analysis (
$\Delta C$
) is presented and the difference compared to the CE is demonstrated by a precision measurement.