FAiL

Brief description

As part of this project, the criticality of failure patterns in battery production will be analyzed and evaluated through the systematic examination of large-format battery cells. The scale of the experiment is crucial to the validity of the results, as aging studies conducted on a laboratory scale often have limited relevance for industrial applications. The innovation encompasses insights for the intelligent production and quality assurance of battery cells, as well as the development of a novel test bench for the time-resolved characterization of “thermal runaways” using imaging techniques. The goal is to identify correlations between defects and the causes of cell failures in order to develop safety measures based on these findings. The core objective is to combine a robust CT system for detecting safety-critical cells and for investigating production defects such as foreign particles. This technology is currently unavailable, despite high industrial demand. Additionally, a demonstrator for high-speed in-situ radioscopy is to be developed using a new liquid-metal X-ray source to enable fast and safe analyses. This solution ensures complete CT penetration of the side walls, providing maximum safety in the event of potential accidents. The project also aims to develop a solution for battery monitoring during operation to detect potential failures at an early stage. However, there is currently a lack of systematic investigations into cell defects to enable the development and validation of targeted detection methods.

The project is divided into six work packages:

WP 1 Project Management and Transfer: In WP 1, project activities are coordinated to ensure that the described project objectives are achieved and that the project results are published. A detailed project management plan ensures that the project is carried out efficiently and in a targeted manner.

WP 2 Definition of Requirements and Critical Failure Patterns: A comprehensive catalog of production-related defects along the battery cell production chain will be created; the failure patterns will be described based on criteria such as material, size, shape, and position. A literature review will supplement the assessment of safety and performance relevance as well as the feasibility of targeted implementation, including transferability to other cell formats. Based on this, the failure patterns are selected and prioritized; the experimental design defines the reference system, experimental matrix, and analysis procedure to maximize statistical significance. Finally, a best-practice guide is created to support follow-up projects and enable an efficient internal evaluation of battery production.

AP 3 Defect Patterns: Feasibility studies examine the practical introduction of defect patterns in accordance with the experimental strategy, including preliminary tests on stability and reproducibility, testing of various processes, intermediate product removal, and manual interventions (adjustments to system parameters if necessary). The flexible PreFab structure enables insertion and removal at multiple process points and utilizes inline measurement technology to ensure representativeness. Defective cells, replicas, and reference cells are then manufactured step by step; pre-characterization is applied to all replicas, and CT verification is performed upon particle introduction; the central challenge remains the production of defect-free reference cells.

WP 4 Development of the high-speed radioscopy/X-ray CT system including a shielding chamber: Concepts for the DR/CT system are developed and validated, taking into account the structural conditions at the installation site as well as integration into the existing infrastructure; motion trajectories and the shielding chamber are coordinated, a specification document is created, and relevant components are procured. The demonstrator is assembled, the X-ray source and detector are tested in the imaging chain, radiation protection is integrated, and a shielding chamber is designed, manufactured, and certified, including a FAT; in parallel, concepts for an in-line DR/CT system are implemented, software is adapted, and a helical CT trajectory with data rates of up to 1,000 images per second is realized, with documentation being created.

WP 5 Defect Analysis: The approach combines filling, connection, and forming/cyclic aging of reference and defective cells with imaging techniques (X-ray CT and high-speed radioscopy) to visualize defects, analyze their causes, and assess safety-relevant conditions. At the same time, the DR/CT demonstrator is being further developed and validated, protective measures are being implemented, and software is being adapted; in addition, digital cell defect diagnostic methods are being established that correlate electrical, end-of-line, and cycling data with CT image data to efficiently detect defects.

WP 6 Post-mortem examinations: Aged cells are evaluated after opening and compared with reference materials to select relevant components for post-mortem examination and elucidate degradation mechanisms. The analyses include optical evaluation, transfer to a glovebox, opening and documentation, as well as SEM/EDX analyses of electrodes and separators, ICP-OES to determine lithium content, and NMR spectroscopy to identify electrolyte decomposition products. The results are compared with digital cell failure diagnostic methods, these methods are further refined, and correlation models for failure identification are developed.

The project helps drive the expansion of energy storage systems to secure jobs in the German battery manufacturing sector and transition pilot plants to highly automated, digitally supported mass production. From a scientific and technical perspective, knowledge transfer to national and international networks is being actively promoted; results are published and integrated into teaching and SME collaboration; Consequential changes and new models are intended to enable the consideration of other cell chemistries as well. The demonstrator serves to achieve production readiness for a high-speed DR/CT system and digital cell defect diagnosis, with prospects for international marketing and potential contracts; post-project, continuation at the demonstrator site is sought. Significant potential of several billion euros is seen in the CT-based inspection market segment, with applications in primary manufacturing and second-life use, while scientific exchange is continuously strengthened through publications, conferences, and continuing education programs.