Electrochemical Impedance Spectroscopy with AVL X-ion™ and AVL Smart EIS™

Accurate analytics of electrochemical cell parameters

The Electrochemical Impedance Spectroscopy (EIS) is an innovative stimulus response testing technology for checking the frequency-dependent internal resistance of electrochemical cells such as batteries or fuel cells.

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AVL X-ion EIS enables battery, electrolyzer, and fuel cell measurement that is both fast and reliable, based on the Electrochemical Impedance Spectroscopy. It can be combined with various AC excitation systems and offers a complete package of solutions, from the stimulus to a high-resolution measurement system for quantifying the response of the inner impedance of the UUT. At the heart of the system is AVL X-ion, a highly dynamic data acquisition unit. In combination with the AVL EIS software, the AVL X-ion EIS solution enables multichannel EIS and harmonics analysis for UUTs up to 1,200 V.

The highly dynamic market transition towards electrification requires a closer look at the individual systems, focusing on battery and fuel cells. To improve their efficiency and lifetime, these components must be analyzed in detail.

Finding errors at an early stage, observing degradation effects, and evaluating the state of health of battery and fuel cells are crucial tasks for a wide range of applications in all stages of development – from R&D to end-of-line tests.

New measurement and evaluation methods like the Electrochemical Impedance Spectroscopy (EIS) provide this detailed information.

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Highly Accurate Measurement Results

The modular structure of the X-ion EIS system enables the perfect fulfillment of a wide variety of requirements. The various possible combinations of AC sources and signal conditioning units allow everything to be covered – from pure Electrochemical Impedance Spectroscopy of PEM FC, batteries, and SOFC, to resonance frequency analysis and impedance spectroscopy of inverters or other DC bus components, for example. The number of measurement channels can also be easily adapted, and it is possible to calculate the cell impedance and analyze the whole stack simultaneously.

Technical Specification  


32 channels: 1 current and 31 voltage     
Up to 191 EIS channels @ 6 cascaded X-ions
Max DCV          1,200 V
Max AC current  200 App
Frequency range 0.1 HZ ... 200 kHz
Measurement resolution 24 bit
Fast EIS Up to 19 frequencies simultaneously


Trolley EIS
Broad Spectrum of UUTs

EIS measurements from the single cell up to HV battery packs and fuel cell or electrolysis stacks.

Fast EIS – Short Measurement Duration 

The option to apply several frequencies to a single UUT (multisine EIS), and the use of pseudorandom binary sequences (PRBS) accelerate measurements.

Multi-Channel Solution

The high-resolution multiple cell analysis (up to 191 EIS channels) allows simultaneous EIS of multiple cells within a stack.

Maximum Flexibility and Utilization

Built into a trolley, the system offers a mobile solution with maximum flexibility, simple setup, and high utilization value.

AVL X-ion™ Platform

AVL X-ion is a highly dynamic, modular data acquisition unit with 8 freely usable slots. This allows X-ion to be used for a wide variety of use cases, for example, those relating to power measurements or NVH measurements.

Signal Conditioning High Voltages and Current Range

To measure high voltages and currents, the High Voltage Probe (HVP) Box and the Current Transducer Supply (CTS) Box are available as extensions for AVL X-ion.

EIS Toolbox Software

The software enables testbed integration with automated test sequences and storage of raw data for further processing and analysis. Integrated evaluations such as impedance lists, Nyquist and Bode plots, calculation of parameter values, and validity checks via Kramers-Kronig relations facilitate operation and interpretation.

AVL Smart EIS™

The all-in-one fast Electrochemical Impedance Spectroscopy measurement system for battery modules, battery packs, fuel cell short stacks, and fuel cell systems. AC excitation and measurement in a single system. DC voltage up to 500 V.

Solution Sheet AVL X-ion™ EIS

EIS measurement system - Accurate analytics of electrochemical cell parameters

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