AIWEI ITS550-500 Fuel Cell Impedance Testing System

Overview

The AIWEI ITS550-500 Fuel Cell Impedance Testing System is a purpose-built, high-fidelity electrochemical impedance spectroscopy (EIS) platform engineered for in-situ, real-time characterization of proton exchange membrane fuel cell (PEMFC) stacks and individual cells under operational conditions. Unlike conventional potentiostats, the ITS550-500 integrates synchronized high-current excitation and multi-channel voltage/current acquisition within a single robust architecture optimized for high-power systems. It employs a dual-module design: a precision AC current injection module (1–50 A, 10 Hz–1.5 MHz) and a galvanically isolated, high-bandwidth monitoring module capable of simultaneous stack-level and cell-level signal capture. The system implements true four-wire Kelvin sensing for low-impedance measurements down to 0.1 mΩ per cell, with 24-bit resolution and 100 kHz sampling—enabling accurate extraction of ohmic resistance (R_Ω), charge-transfer resistance (R_ct), and mass-transport contributions across the full frequency spectrum. Its 1000 V common-mode isolation and Class I EMC/EMI compliance ensure stable operation in electrically noisy environments typical of power electronics integration (e.g., alongside DC/DC converters and electronic loads).

Key Features

• Single-channel electrochemical workstation with scalable current capacity (0–500 A or 0–1000 A continuous output)
• Wideband EIS capability: 10 Hz to 1.5 MHz frequency sweep range, supporting both logarithmic and linear scanning modes
• Galvanically isolated stack voltage input (500 V / 1000 V ranges) and optional 5-channel cell voltage monitoring (5 V / 50 V / 100 V / 200 V ranges)
• 24-bit analog-to-digital conversion with 100 kHz maximum sampling rate and <0.1% RDG voltage accuracy
• AC excitation current source with 0.2% RDG + 0.1% FS accuracy and programmable amplitude, phase, and waveform shape
• Integrated common-mode rejection >120 dB at 1 MHz; 1000 V DC withstand rating for safe testing of large-area stacks
• Real-time impedance calculation engine with on-board FFT processing and configurable averaging (1–64 cycles)

Sample Compatibility & Compliance

The ITS550-500 supports PEMFC, DMFC, and SOFC stacks up to 200 cells (depending on total voltage and thermal management). It accommodates standard bipolar plate configurations and interfaces seamlessly with commercial stack cooling and humidification subsystems. All signal conditioning circuits meet IEC 61000-4-3 (radiated immunity) and IEC 61000-4-4 (electrical fast transient) requirements. The system adheres to ISO 17025-relevant traceability principles for measurement uncertainty reporting and supports audit-ready data logging compliant with GLP and GMP documentation workflows. While not FDA 21 CFR Part 11-certified out-of-the-box, its software architecture permits configuration of electronic signatures, user access levels, and immutable audit trails when deployed in regulated R&D or validation laboratories.

Software & Data Management

The system operates via AIWEI’s proprietary FC-IMP Suite—a Windows-based application providing intuitive setup of EIS protocols (frequency range, points/decade, amplitude, settling time), real-time Nyquist/Bode visualization, and automated equivalent circuit fitting using non-linear least squares (NLLS) algorithms. Raw time-domain waveforms and complex impedance spectra are saved in HDF5 format with embedded metadata (timestamp, environmental conditions, operator ID, calibration history). Export options include CSV, MATLAB .mat, and IMP format for third-party analysis tools (e.g., Thales, EC-Lab, ZView). The software includes built-in diagnostic checks for electrode contact integrity, signal-to-noise ratio (SNR) validation, and harmonic distortion detection—ensuring data quality before storage.

Applications

• In-situ diagnosis of membrane hydration loss, catalyst degradation, and gas diffusion layer flooding during dynamic load cycling
• Quantitative assessment of interfacial resistances across MEA components (catalyst layer, membrane, GDL) under varying temperature and stoichiometry
• Validation of stack-level control strategies by correlating EIS-derived parameters with voltage efficiency and thermal profiles
• Accelerated stress testing (AST) protocol execution per DOE and JARI guidelines for durability benchmarking
• Integration into hardware-in-the-loop (HIL) test benches for fuel cell system controllers and energy management units

FAQ

What is the minimum measurable impedance per single cell?
The system achieves a resolution of 0.1 mΩ per cell under optimal SNR conditions (≥40 dB), validated using NIST-traceable low-impedance shunts.
Can the ITS550-500 perform simultaneous EIS on multiple cells within a stack?
No—it performs sequential cell-level EIS via multiplexed voltage inputs; however, all five cell channels can be sampled synchronously at up to 20 kHz per channel for time-domain analysis.
Is external triggering supported for synchronization with auxiliary equipment?
Yes—TTL-compatible trigger I/O (input/output) is provided for precise timing alignment with DC/DC converters, data loggers, or environmental chambers.
Does the system support custom equivalent circuit models?
Yes—users may define arbitrary R-C-L topologies in FC-IMP Suite and export parameter constraints for batch fitting across datasets.
What calibration standards are included with delivery?
Each unit ships with a certified 10 mΩ and 100 mΩ reference shunt, NIST-traceable voltage divider, and full calibration certificate valid for 12 months.