Batch Diagnosis of Batteries within One Second

As the demand for efficient and sustainable energy storage solutions increases, ensuring uniform performance across batteries becomes a key challenge. The development of efficient, reliable, and low-cost diagnostics is critical for identifying cell-to-cell inconsistencies and subtle differences for both factory-manufactured and second-life recycled batteries. To this end, this study presents a multi-channel and multi-frequency electrical excitation response (MMER) technique, containing the same impedance information as electrochemical impedance spectroscopy (EIS), but capable of screening multiple batteries in one second. The MMER technique significantly reduces measurement time from several minutes per EIS measurement — which scales with the number of cells — to just one second for the entire module. A comparative analysis between individual multi-frequency voltage responses and individual EIS reveals that multi-frequency voltage responses provide equivalent results of battery consistency and performance rankings compared to EIS, with reduced measurement time from ten or more minutes to several seconds. Furthermore, the integration of multi-channel technology enables simultaneous measurement of multiple batteries, maintaining measurement time comparable to that of a single cell, independent of the number of batteries. This approach not only enhances the screening efficiency but also eliminates errors associated with repeated set-up of individual tests. The diagnostic results from MMER align with true performance characteristics obtained from the discharge profile. The proposed technique offers a practical solution for pilot/industrial-scale battery diagnostics and holds potential for broader applications in any electrochemical device, such as fuel cells or electrolysers. It also opens up the door for ‘operando’ EIS-like measurements, whereby the previous restriction that the system has to be in a steady state (and therefore being measured at 0 A current) for traditional EIS does not apply to this technique. The one-second measurement time means that our diagnostic system is effectively at a steady state even with higher charge/discharge currents of up to 10 C.