In addition to the development, implementation and validation of the demonstrators, four research areas are the main focus of the project SEEDs: DC networks and electrical storage, supply network simulators, gas-current coupling and cold-storage systems. The Fraunhofer Institute for Silicate Research (ISC) not only provides a new battery prototype, but also the comprehensive know-how in the characterization and analysis of storage modules and systems.
So far, however, nobody knows the exact relationship between the tension - how and with which defined force the electrodes are stressed in the battery cell - and their service life. The Fraunhofer R&D Center for Electromobility Bavaria, part of the Fraunhofer ISC, therefore uses demonstrator cells to investigate how potential - and possibly inhomogeneous - module stresses, pressure, temperature and electrode potentials affecting the service life and performance of a battery. To this end, the scientists are developing "intelligent" cells that can measure these influencing factors in a cell during the operation.
The sensors are integrated directly into the lithium-ion cells. They continuously determine the state of the entire cell network with regard to charge and aging behavior and provide information on how different operating conditions affect the cells. As pressure sensors are used such sensor types that due to their low overall height, are suited for installation in cell modules and measure by compression or force.
For the production of intelligent cells, the Fraunhofer ISC has semi-automated production processes under defined climatic conditions. The electrodes are continuously coated on-site using a roller-to-roller system in the clean room. For comparison purposes, battery modules from commercially available cells are constructed and tested in actual operation. Subsequently, an extensive post mortem analysis will identify, among others, construction-related local stresses. Based on the results of the cell-internal sensor analysis and the post-mortem analysis, recommendations for the design and construction of cells and battery systems are developed.
More information https://www.fzeb.fraunhofer.de