Lithium-ion batteries (LIB) are the key component of electrical energy storage. The improvement of their properties provides enormous potential for increased market penetration of electric mobility on land, at sea and in the air. However, stationary energy storage devices and electronic consumer products would also benefit greatly from the further development of LIB. The composition of the electrodes defines numerous properties of the LIB, such as available capacity, fast charging capability and power supply. During charging and discharging, lithium is inserted into and extracted from the active materials. However, the porous structure of the electrode results in long and complex lithium-ion transport paths in the electrolyte. These result in strong lithium concentration gradients in the electrodes, which cause a drop in the available capacity due to lithium depletion on the active material surfaces. The introduction of structures into the electrodes represents a proven approach to reduce the lithium concentration gradients mentioned above.
The ProfiStruk project addresses the use of alternative and superior structuring processes that address an alternative to laser-based processes with too low process speeds for mass production. The aim of the project is the integration of plant technology for structuring into the existing production line for lithium-ion cells. At the same time, a plant for the discontinuous injection of structure formers without loss of active material will be established and the structuring process will be validated by the production of large lithium-ion cells. The challenge is the development of processes and equipment for inline structuring using both mechanical and process engineering processes.
The process design at the Technical Universities of Munich and Braunschweig is based on previous investigations of structure dimensioning and distribution. In this respect, laser-structured electrodes are used as a model methodology for the validation of advantageous structures and the resulting tool and process design. Evaluation criteria are electrochemical investigations of the generated structured electrodes, which are correlated with the structural, mechanical and electrical electrode properties in the sense of systemic structure development.