Electrode Manufacturing: PEM Helps Classify Coating Defects

Electrode foil coating line Copyright: © PEM RWTH Aachen University

The chair "Production Engineering of E-Mobility Components" (PEM) of RWTH Aachen University, together with two other research institutions, is dedicated to the classification of coating defects in electrode production in the "KritBatt" project. Such defects, which have occurred to date during production, reduce yield and lead to high follow-up costs. The project is an accompanying project of the federally funded competence cluster "Analytics/Quality Assurance" (AQua) and is intended to contribute to the determination of criticality in electrode production.

Lack of criticality criteria

To date, there has been a lack of so-called criticality criteria that describe a relationship between the type and extent of coating defects and their effects on the electrochemical properties of the electrodes, so that appropriate tolerance limits can then be defined for electrode production. Due to the complexity of the processes, empirical quality measures currently exist only without a clear correlation to cell performance. However, it is precisely these process-structure-property relationships that need to be identified in order to establish efficient quality management for cell manufacturing.

Innovation module for testing technology in electrode production

As a significant contribution to this, a pre-qualified laser speckle photometry (LSP) system for on-site monitoring of the coating quality of electrode foils will be further developed and correlated with innovative defect detection methods as part of the "KritBatt" project. The integration of the LSP system into a roll-to-roll process thus achieves a technology maturity value of about 5, based on today's "proof of concept". The goal is a validated prototype as an innovation module for testing technology in electrode manufacturing, including data evaluation for transfer to the Fraunhofer Research Institution for Battery Cell Production FFB in Münster.

PEM takes over benchmarking of the new process

In the "KritBatt" project, the PEM team is concerned with benchmarking the newly developed LSP process on a roll-to-roll system using commercially available optical testing technology. Subsequently, both processes will be validated by building defect and non-defect multilayer pouch cells with sufficient statistics. At the end of the research project, acceptable tolerance limits will be defined with regard to defect size and density, for example, which must be observed during further processing of the electrodes.



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The project

  • "KritBatt": Inline classification of coating defects to determine criticality in electrode manufacturing

Research objectives

  • Development of a common defect catalog for the first main stage of battery cell production (electrode production)
  • Improvement of quality assurance measures in cell production through
    • use of an innovative inline measurement device (laser speckle photometry) for the detection and AI-based classification of defects in the electrode coating
    • determination of the relationships between process parameters and defect formation in electrode production (mixing, coating, drying)
    • identification of the mechanisms of action of the defects to assess criticality in the application

Research and project partners

Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) (project coordinator)
PEM of RWTH Aachen University
Institute of Materials Science (IFWW) (TU Dresden)


  • 03/01/2021 through 02/29/2024

Project management

Projektträger Jülich (PtJ)

Funding code

  • 03XP0360C


Federal Ministry of Education and Research (BMBF)