Real-time detection of health-related processes in lithium-ion batteries through AI-supported characterisation for resource-efficient exploitation of reuse potential

Funding: BMBF

Duration: 01/23 - 12/25

Abstract:

The KI2L project is a joint project involving several institutes and companies that aims to promote the reuse of electric mobility battery stacks in stationary applications. The aim of this sub-project is to develop a manufacturing separation and joining concept for the replacement of pre-aged lithium-ion cells. Since individual cells in battery stacks age at different rates, reprocessing is intended to enable a second phase of use in stationary energy storage applications.

The individual cells are connected by welded cell conductors. In order to separate battery elements from each other, a concept for automated separation and joining at this connection point must therefore be developed. Following a material analysis of the common cell conductor connections "prismatic cells", "pouch cells" and "round cells", laser cutting, where necessary with the addition of various process gases, and alternatively robot-assisted milling of these joints are being tested. Laser welding is being considered for joining, whereby the influence of process parameters (feed rate, power and shielding gas) and seam preparation are being investigated. The present investigations show that laser deep welding can be used to produce reproducible joints, and that laser cutting can also be used to safely separate cell conductors with low energy consumption.

At the same time, preparations are being made for the automation of the cutting and joining processes. Based on high-resolution 3D scans, this involves offline processes with the generation of tool paths in a CAD environment on the one hand, and on the other hand, an online approach with automated image recognition and the use of distance sensors is being developed in collaboration with industry partner AIM Systems. 

In collaboration with AIM Systems, a safety concept is also being developed that will serve as the basis for later work on real, uncharged battery stacks. The project is thus creating the technological and safety requirements for the automated reprocessing of battery stacks for a second life.