InnoCase - Innovative housing concepts for large-format lithium-ion batteries

The project InnoCase focuses on researching and developing innovative housing concepts for large-format lithium-ion cells (LIZ) that combine the advantages of various conventional housing types. Through innovative approaches, the dead volume and the mass of prismatic hardcase housings are to be reduced in order to achieve an increase in energy density. At the same time, changes in the manufacturing processes and procedures of the housings will be investigated in order to optimize cell assembly. This is expected to save costs in LIZ production.

Lithium-ion cells (LIC) are used as electrochemical energy storage devices in a variety of applications. The cell-internal components (electrodes, separators and electrolyte) are surrounded by a housing which is subject to a number of requirements. It shall protect the cell interior from external influences (moisture, dirt, etc.) as well as prevent the leakage of the cell-internal, partly toxic and flammable substances. In addition, the cell housing must assume the cooling function, fulfil requirements with regard to integration into the module and be as cost-effective as possible and easy to manufacture.

The increase in the specific energy density of a LIC depends largely on the improvement in the ratio between active and inactive components. For this reason, a housing concept is first developed that is not only optimized with regard to mass and volume efficiency, but also takes electrical and thermal properties into account. However, since large-format LICs impose increased requirements on cell design (temperature distribution, electrical conductivity over large electrode surfaces, safety properties, energy density), numerically supported cell layout is another focal point of the project. By applying Design for Manufacturing and Assembly (DfMA) methods, innovative housings can be created that are suitable for assembly. At the same time, the integration into a module must be facilitated when designing a new housing. In addition, production aspects are addressed by adapting and simplifying processes in cell assembly. The use of new manufacturing technologies, such as laser welding for joining thin collector foils at stack level, is intended to demonstrate significant advantages in terms of production costs and costs.

These challenges are addressed in the project InnoCase in a consortium of industry and research that includes partners along the entire value chain of LIC housings. The consortium consists of three German research institutions (Technical University of Munich: Institute of Machine Tools and Industrial Management (iwb), Chair of Electrical Energy Storage Technology (EES); RWTH Aachen University: Chair of Production Engineering of E-Mobility Components (PEM)) as well as four German companies (ElringKlinger AG, TRUMPF Group, MANZ AG, Futavis GmbH).

Acknowledgement

The iwb would like to thank the Federal Ministry of Education and Research (BMBF) and the Project Management Organisation Jülich for funding this research project (funding code: 03XP0207F).

Duration 01.02.2019 bis 31.01.2022
Funded by BMBF - Federal Ministry of Education and Research