EIS — Electrochemical Impedance Spectroscopy

Electrochemical impedance spectroscopy is a procedure NOVUM uses to check batteries for their general functionality as well as state of charge, residual capacity and expected service life. In this process, current is sent into the battery within a certain frequency range, which generates various response signals. In this way, we obtain a non-invasive image of the chemical processes inside the battery, which we evaluate using neural networks.

How does electrochemical impedance spectroscopy work at NOVUM?

The NOVUM team has developed stationary and mobile test systems for the electrochemical impedance spectroscopy of batteries. Battery modules, battery packs and even individual battery cells can be tested within seconds on the Battery Analyzer and Cell Analyzer.

The mobile test system from NOVUM, which fits in any pocket, is the perfect addition for battery tests that need to take place on the move, e.g. for logistics companies that operate large fleets.

The data collected is encrypted and sent to the NOVUM Cloud, where it is analyzed by our AI. After a few seconds, the results are then available to NOVUM customers on the user interface in a clear and easy-to-understand format.

The following steps characterize electrochemical impedance measurement at NOVUM:

  • Application of modulated direct current
    In electrochemical impedance spectroscopy, modulated direct current is used to investigate the electrochemical processes in the battery. We measure within a certain frequency range and thus obtain an image of different areas of a battery. This not only allows us to determine the state of health, the state of charge and the capacity, but also to see if there are defects in the battery, such as dendrite formation, which can impair the performance of the battery and lead to serious problems such as a short circuit.

  • Measuring the voltage response
    When we send current into the battery, we get a kind of voltage echo that can be displayed in the form of a curve and provides detailed information about the chemical processes within the battery and its condition. This curve is known as an impedance spectrum. The data collected is then sent to the NOVUM Cloud in encrypted form.

  • Analysis using artificial intelligence
    By analyzing these diagrams, NOVUM’s artificial intelligence — or more precisely, up to five different AIs whose strengths we combine — can derive various electrochemical properties of the battery. These include the state of health, the state of charge, the residual capacity, the residual value of the battery and various defects that are not visible from the outside.

When is electrochemical impedance spectroscopy used at NOVUM?

In principle, electrochemical impedance spectroscopy can be used for stationary and mobile battery diagnostics as well as for battery storage monitoring. We always use the method for battery diagnostics.

In monitoring, it is only used if the existing system data is not available in sufficient quantity or quality for the artificial intelligence to make valid statements.

Why does battery diagnostics with electrochemical impedance spectroscopy only take 90 seconds at NOVUM?

Electrochemical impedance spectroscopy generally only takes a few seconds. What makes battery diagnostics time-consuming is the correct interpretation of the data. The fact that we can interpret this data with the help of AIs has made the process much faster and more accurate than older methods.

When is electrochemical impedance spectroscopy used in battery storage monitoring?

The decisive factor is whether your data is available in sufficient quantity and quality. Current, voltage and temperature at intervals of a few seconds to a maximum of five minutes are particularly important.

If this is not the case, you can still use our AI-based technology for your battery storage system. We would then collect the data ourselves using our hardware. Please contact our team if you have any questions.

How do I know that NOVUM’s electrochemical impedance measurement delivers correct results?

NOVUM’s technology is backed by 10 years of development work. Several AIs are used, which check each other. Problems and anomalies are identified immediately. In addition, our team of experts is always available to answer any questions or concerns you may have. Well-known companies such as LEAG, Shell and the Deutsche Bahnbau Group are already using NOVUM technology.