Safe electric micromobility

For the mobility transition and the widespread use of electric vehicles, such as e-bikes, it is important to monitor the service life and safety of energy storage systems efficiently. This is where electrochemical impedance spectroscopy (EIS) comes into play – an innovative method that we are developing and continuing to improve.

What is EIS?

EIS stands for electrochemical impedance spectroscopy. This technique helps us to better understand a battery’s condition. It measures how the battery responds to various electrical signals, which provides us with information about its condition and efficiency.

What is DEIS?

DEIS stands for Distributed Electrochemical Impedance Spectroscopy. This advanced method builds on traditional electrochemical impedance spectroscopy (EIS) and extends it to enable the real-time monitoring of the condition of battery cells in large energy storage systems whilst they are in operation.

Why is this important?

With accurate information about the battery’s condition, we can:

• Extend the battery’s service life by optimising its use.
• Improving safety by identifying potential problems at an early stage.

The test system in our laboratory

In our laboratory, we have developed a compact test system that combines the battery, the battery management system and the power electronics. This versatile platform enables us to test new monitoring methods for functionality. From small e-bike batteries to large stationary energy storage systems, we can cover a wide range of applications. This intelligent monitoring technology is a crucial step towards a sustainable and safe transition to electric mobility. It enables us to be better prepared for a future in which electric vehicles play a central role.

The innovation in our method for monitoring energy storage systems lies in several key areas:

1. Precise monitoring during operation:

Traditional methods of monitoring batteries often require the battery to be taken out of service in order to make accurate diagnoses. With our further development of distributed impedance spectroscopy (DEIS), we can monitor the condition of individual battery cells whilst the battery is in operation, without interrupting it. This enables a continuous and dynamic analysis of battery health.

2. Improved accuracy of state estimation:

By using EIS, we can obtain very detailed information about the electrochemical state and properties of the battery. This means a more accurate assessment of the battery’s condition compared with conventional methods.

3. Temperature monitoring for safety and performance:

A particular advance is the ability to accurately measure the temperature distribution throughout the entire battery system. Temperature variations can indicate potential problems or unsafe operating conditions. Monitoring the temperature distribution is therefore a crucial factor in ensuring both the safety and longevity of the batteries.

4. Versatility and range of applications:

The compact test system developed in our laboratory integrates the battery, battery management system and power electronics, resulting in a flexible test platform. This platform makes it possible to test the new monitoring methods in a range of applications, from small devices such as e-bikes to large stationary energy storage systems. It therefore offers a wide range of potential applications in the mobility and energy storage sectors.

5. Extended battery life:

Precise condition monitoring helps to optimise charging strategies and prevent potential damage, which directly leads to an extension of the battery’s service life. In summary, this innovative monitoring technology not only offers increased efficiency and safety, but also helps to enhance the cost-effectiveness and sustainability of energy storage systems – key factors for the success of the energy transition and mobility.