Digital Impedance Emulator for Battery Measurement System Calibration

Area of Science:

• Electrical Engineering
• Materials Science
• Electrochemistry

Background:

• Battery internal state information is crucial for effective battery management systems (BMS).
• Electrochemical Impedance Spectroscopy (EIS) is a key technique for online battery control and diagnostics.
• A stable impedance reference is essential for calibrating and testing BMS due to battery impedance variability with state of charge and aging.

Purpose of the Study:

• To propose a programmable impedance emulator for calibrating BMS based on EIS.
• To develop a controllable and low-cost reference for battery impedance measurement systems.

Main Methods:

• Implementation of a digital finite-impulse-response (FIR) filter programmed to replicate real battery impedance.
• Derivation of an analytical expression for battery impedance from an equivalent circuit model.
• Validation of the model via numerical simulations and experimental tests.
• Implementation of the FIR filter on a low-cost microcontroller unit (MCU).

Main Results:

• The FIR filter successfully reproduced the target battery impedance in the frequency domain.
• The emulator was implemented on an MCU and validated using custom EIS and commercial instruments.
• Experimental results demonstrated the feasibility of the proposed emulator.

Conclusions:

• The developed programmable impedance emulator provides a feasible, controllable, and low-cost solution for calibrating EIS-based BMS.
• This approach enhances the accuracy and reliability of battery diagnostics and management.