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Current collectors in focus of Li-Ion battery development at ZBT

Micro-structured power collectors were the main focus of work in a now completed project. The findings are being incorporated into innovative approaches to the development of three-dimensional current collectors.

Li-Ion battery development at ZBT

Together with fem from Schwäbisch-Gmünd we have completed the project "Flexible lithium-ion cells with microstructured current collectors to increase flexibility, adhesion and volumetric energy density". Different methods for structuring current collectors based on established processes in the field of metal processing or metal deposition were investigated. On the battery side, influences of the process during the application of the active material, but also influences of the used binder with regard to the above mentioned objectives were included in the investigations.

Two research centres were involved in the project: fem (Forschungsinstitut Edelmetalle + Metallchemie) and ZBT (Zentrum für Brennstoffzellen-Technik) from Duisburg. The fem investigated different structuring possibilities and was responsible for the structural elucidation of the modified current collectors and electrodes. ZBT took over the electrode and cell manufacturing, the electrochemical characterisation of the produced cells and the mechanical test of pouch cells. The results are summarised in a comprehensive final report, which will be published by the TIB Hannover and the member association (German). A short summary of the results can be downloaded (german):

Project: Flexible lithium-ion cells with microstructured current collectors to increase flexibility, adhesion and volumetric energy density, duration: 01.03.2017 - 29.02.2020, Project No. 19492 N (Kurzzusammenfassung)

Forschungsvereinigung: Verein für das Forschungsinstitut für Edelmetalle und Metallchemie e.V. - FEM       www.fem-online.de

Research performed by:

The findings and characterisation methods are now being incorporated into a newly started project focusing on three-demensionally structured current collectors:

To increase the energy density of lithium-ion batteries (LIB), the mass of the electrochemically inactive components of the electrode must be reduced. This can be cone by increasing the mass loading of the electrochemically active materials. However, the traditional electrode architecture is based on thin layers applied to metal foils and does not allow a further increase in loading. The aim of the project LiBaStrom is the realisation of innovative electrode architectures based on three-dimensional (3D) current collectors, e.g. metal and graphite foams, carbon papers or expanded metals. 3d structured current collectors are characterised by a continuous electrically conductive network enabling a fast electron transfer through the entire electrode even at high mass loadings. A silicon-based composite material is to be used for the anode. Due to its enormous storage capacity the energy density can be significantly increased compared to the standard anode material graphite. Lithium nickel cobalt manganese oxide (NCM) is to be used on the cathode. NCM is suitable for applications requiring high energy content, e.g. electric vehicles or portable electronic devices. At cell level, a significant increase in gravimetric energy density of 25-35% can be estimated for 3D structured current collectors compared to foil-based electrodes. Both described material routes for anode and cathode production are demonstrated on a pilot plant scale.

SMEs as manufacturers of 3D current collector materials as well as electrodes for LIB and plant engineering companies will benefit from the results and will receive essential information for the adaptation of the coating technology for the production of 3D structured electrodes. The project-accompanying committee is open to other interested companies.

Project:

Entwicklung von Lithium-Ionen-Batterien hoher Energiedichte mit Elektroden auf Basis dreidimensionaler Stromabnehmer (LiBaStrom), 58 EWBG, 01.06.2020 - 30.11.2022

Forschungsvereinigung: Institut für Energie- und Umwelttechnik e.V. - IUTA  www.iuta.de
Forschungseinrichtungen:

  • Universität Duisburg-Essen, Institut für Energie- und Umweltverfahrenstechnik Fachgebiet Energietechnik
  • Zentrum für BrennstoffzellenTechnik ZBT GmbH,  department electrolysis and batteries
  • Fraunhofer-Gesellschaft e.V., Fraunhofer-Institut für Keramische Technologien und Systeme IKTS Standort Hermsdorf
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