Influence of position and intensity of production-caused inhomogeneities on the spatially-resolved performance parameters and total performance of lithium-ion cells

• Applicant: Professorin Dr.-Ing. Julia Kowal
• Subject Area: Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461805740

• Final Report Year: 2024

Final Report Abstract

The project focused on optimizing production processes for lithium-ion batteries (LIBs) by investigating the impact of inhomogeneities and production-related defects on battery performance and lifespan. The goal was to develop methods to identify such defects, analyze their effects, and enable improvements in the manufacturing process. Key outcomes include: Enhancing production standards in research: Guidelines and standardized procedures for the reproducible fabrication of test cells were developed. Development of innovative cell formats: Novel cell designs featuring customized casing materials to accommodate pouch cell materials were created. CT-imaging was demonstrated to effectively identify nearly all relevant defects, such as metallic contamination, line defects (e.g., missing active material), scratches, or cuts, with the exception of folds. Additionally, the limitations of this imaging method were identified. Development of a test cell and a spatially resolved battery model (oESBM): This model accounts for inhomogeneities and provides precise predictions of performance degradation. These results contribute significantly to LIB research by helping researchers and manufacturers better understand, detect, and prevent defects.

Publications

• Reproducibility of Small-Format Laboratory Cells. Energies, 15(19), 7333.
  Luc, Paul-Martin; Buchwald, Fabio & Kowal, Julia
  
• Reproducible Production of Lithium-Ion Coin Cells. Energies, 15(21), 7949.
  Luc, Paul-Martin; Bauer, Simon & Kowal, Julia
  
• Detection of Manufacturing Defects in Lithium-Ion Batteries-Analysis of the Potential of Computed Tomography Imaging. Energies, 16(19), 6958.
  Evans, Daniel; Luc, Paul-Martin; Tebruegge, Claas & Kowal, Julia
  
• Comparison and Teardown of Na- and Li-Ion 18650 Cells. Elsevier BV.
  Droese, Dominik; Luc, Paul-Martin; Otto, Martin; Schlösser, Anton Emil Kasper; Evans, Daniel & Kowal, Julia