Electrochemical Energy Storage - EES -

The Electrochemical Energy Storage group studies batteries and electrolysers to integrate fluctuating renewable energies into the energy system. Building on projects regarding hydrogen storage and various fuel cell systems, they are currently concerned with PEM electrolysis systems and vanadium redox flow batteries. Individual components and systems are being optimised in close cooperation with academic chairs and industrial partners – always aiming to increase efficiency, maximise service life, and reduce costs.

The main work focuses are:

  • Investigation of electrochemical systems
  • PEM electrolysers
  • PEM electrolysers
  • Vanadium redox flow batteries
  • Analysis and further development of materials
  • Development of cell and stack designs for increased performance
  • Degradation measurement
  • Analysis of electrochemical systems in various applications

Head of Group:
Dr. Matthias Rzepka
Walther-Meißner-Str. 6
85748 Garching
Tel.: +49 89 329442-31
Fax: +49 89 329442-12

Deputy Head of Group:
Tobias Greese M.Sc.
Walther-Meißner-Str. 6
85748 Garching
Tel.: +49 89 329442-66
Fax: +49 89 329442-12

Services & Equipment


  • Analysis of PEM electrolysers and redox flow batteries
  • Further development of cell components (e.g. electrode materials)
  • Design and construction of individual cells and stacks
  • Production of membrane electrode assemblies (MEA)
  • Electrochemical characterisation of cell components
  • Analysis of loss mechanisms and performance measurements on individual cells and stacks (laboratory and industrial scale)
  • Catalyst screening
  • Investigation of catalyst degradation
  • Techno-economic modelling of storage systems in different applications
  • Modelling of charge and mass transport at cell level
  • Simulative analysis of ageing phenomena


  • PEM electrolysis testing systems
    • Laboratory cells and stacks for material testing
    • Stack testing rig for up to 10 cells, up to 600 A
    • Two individual cell testing rigs up to 30 A
    • Testing rig for water transport and catalyst degradation
    • Electrochemical impedance spectroscopy, current-voltage characterisation and cycle measurements in the entire DC range
  • Redox flow testing systems
    • Laboratory cells for material analyses
    • Measurement of stacks and prototypes up to 15 kW
    • Electrochemical impedance spectroscopy, current-voltage characteristics, and cycle measurements with state-of-charge and temperature control
  • Three-electrode measurement setup and rotating disk electrode (RDE) setup
  • Laboratory equipment for the analysis of electrolytes and pre-treatment of electrodes (plasma system, high-temperature furnaces)
  • Mass spectrometer for gas analysis
  • Redox flow models for system simulation (Matlab, Python)
  • COMSOL Multiphysics cell models for material and transport simulation as well as fluid simulation


Kopernikus-Project Power2X - Development of a Highly Efficient Electrolysis System (PEM) for the Production of Hydrogen from Renewable Energies at Reduced Precious Metal Consumption

ZAE Bayern KopernikusPower2X Projekt

The paramount goal of the research cluster in the P2X Kopernikus-project is to transfer the findings of previous fundamental work into practice. The novel catalysts for the anode side of hydrogen producing PEM electrolysis will be combined with particularly thin membranes and integrated into an adapted commercial cell stack with a maximum output of several 100 kW. An important consideration in this respect is whether or not these stacks' service life is long enough. ZAE Bayern will take charge of characterising the performance and investigating the long-term stability of short stacks provided by other project partners. Moreover, the long-term loss of precious metal (iridium) in real PEM electrolysis cells will be assessed.

Head of Project: Maximilian Möckl, maximilian.moeckl@zae-bayern.de
Project Duration: 09/2019-08/2022

openBEA - Open-Source Battery Models for Modelling Energy Systems in Grid Applications

ZAE Bayern-open_BEA Projekt -  Graphik

The upcoming energetic coupling of the transport and electricity sectors as well as the options offered by grid-integrated energy storage create new potentials and challenges alike. The effects of grid-integrated storage on the need for further grid expansion or the potential use of battery-electric vehicles as a flexibility option, for example, have not yet been looked at in detail. Investigating these scenarios requires a detailed and complete system model which covers battery storages, electric mobility, and time series of the future electricity generation in distribution grid structures.

In cooperation with the Technical University of Munich and the Reiner Lemoine Institute Berlin, an open-source modelling tool is being realised and made publicly available in the open_BEA project. This simulation platform allows for the detailed modelling of the ageing and performance of redox-flow and lithium-ion storage systems as well as time series simulations of a complete distribution network with a large number of producers, consumers, and storages. The newly created software may be used, for example, to model how to best position, dimension, and operate stationary storage units to provide grid-serving services such as reactive power. Similarly, parameterised simulations can be used to find the most cost-effective storage technology for a given application.

Head of Project: Dr. Matthias Rzepka, matthias.rzepka@zae-bayern.de
Project Duration: 11/2018-10/2021

Website: www.openbeaproject.wordpress.com/

ELVABATTslim - Development of Innovative Thin Electrodes and Adapted Flow Frames to Increase the Efficiency of Vanadium Redox Flow Batteries

ZAE Bayern ELVABATTslim - Apparatur Aufbau

The project aims at the timely provision of a new generation of efficient and low-maintenance electrical redox flow storage systems. These serve to smooth out fluctuations in renewable electricity generation and, thus, contribute to the energy system transition. The main focus lies on improving the redox flow battery's core component, the converter unit, which consists, among other elements, of electrodes and adapted flow frames.

Simulations and measurements of such electrodes in the predecessing project ELVABATT have shown how an unexpectedly large proportion of the electrode volume is not fully incorporated into the redox reaction. Due to the low ionic conductivity of the electrolyte, the reaction mostly takes place close to the membrane. Therefore, only about 1 mm of the electrode's thickness, which is usually about 4 mm, is effective with the rest remaining largely unused to date.

Hence, thinner electrodes are being developed in the ELVABATTslim project, which, when combined with a novel electrolyte flow guidance system, achieve at least a doubling in volume-specific power density. This allows for a more compact stack design, a significant reduction in material and thus battery cost, and, consequently, further improvement of the marketability of VRFB storage technology.

Head of Project: Stefanie Tafelmeier, stefanie.tafelmeier@zae-bayern.de
Project Duration: 11/2019-10/2021

ZAE Bayern

We conduct applied research at the interface between basic science and industrial application. Our methods and systems aim to achieve CO2 neutrality and thereby counteract climate change through the intelligent and efficient use of renewable energies.

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