Challenges in testing.

Batteries are complex electrochemical devices that undergo extensive testing through materials development. A wide array of microscopic and spectroscopic techniques can evaluate cell quality, but these in-depth tests are capital-intensive and often destructive. Thus, nondestructive full-cell tests are limited to time-intensive self-discharge testing over many days or cycle-life testing over many weeks.

The case for impedance spectroscopy.

The impedance of a battery is the measure of the cell’s opposition to a change in current when a voltage is applied and is quantified by the magnitude and phase relationship between current and voltage at a given frequency. Measuring the impedance of a battery across many frequencies — electrochemical impedance spectroscopy (EIS) —enables a nondestructive test that offers information about the internal components of the battery. EIS is a well-known technique, but its use has been limited due to high cost of test equipment and long time of test. Furthermore, battery impedance is highly sensitive to factors such as temperature and state of charge, making interpretation of impedance data difficult.

Get more from impedance.

We believe that a clearer understanding of battery impedance is key to alleviating bottlenecks in battery testing. From laboratory testing to cell manufacturing quality control, better diagnostics will enable more informed decisions sooner.

Since 2014, Hive Battery Labs has been developing equipment and impedance analytics to expand the use of impedance spectroscopy, from battery management integrated circuits to high-power, multi-channel combined EIS potentiostat/cell cyclers. Please reach out for more information.