Do Minh Nguyen

and 3 more

As Lithium-ion batteries (LIBs) are forecasted to reach their technological optimization limits in the coming decade, next generation battery technologies, such as solid-state batteries (SSBs), are investigated to enable even higher energy and power densities. However, depending on the utilized solid electrolytes (SEs), the cell components exhibit low mechanical stability or an adhesive behavior with serious implications on handling during cell assembly. Additionally, mainly SSB cell components with one-sided coating are currently available, which limit the automated cell assembly to the production of bicells with challenges in securely changing the component's orientation during stacking with established gripping technologies. In the present research, a drum gripping concept for a secured change of the cell components' orientation along its pitch axis during handling is introduced. Especially relevant is the avoidance of undesirable folds in the materials which occur in dependence of the adjustable pressure difference and the gripper's rotation direction. To validate the applicability of the presented concept, an experimental evaluation of the deposition accuracy in relation to the supplied pressure difference with polymer-based SEs and lithium metal anodes is carried out. As key results, adequate deposition accuracies are achieved with deposition with the original orientation and for pressure differences of 0.5 bar. Overall, the proposed gripping concept can be viewed as a valid solution for a flexible automated cell assembly of early-stage test cells which are required for further developments towards the establishment of industry-scale SSB production.

Do Minh Nguyen

and 2 more

Lithium-ion batteries (LIBs) immensely contribute to the electromobility’s success for achieving climate change goals. As LIBs are forecasted to succumb to optimization limits in the coming decade, next generation battery technologies, such as all-solid-state batteries (ASSBs), gain noteworthy attention for meeting ever-increasing cell performance requirements. By deploying solid electrolytes (SEs), compared to liquid electrolytes in current LIBs, ASSBs benefit from enhanced safety against flammability and allow for the usage of lithium metal anodes for higher energy densities. Here, polymer solid electrolytes, such Polyethylene oxide (PEO), are widely used for their high flexibility and hence beneficial processability properties compared other SEs. However, their adhesive behavior poses challenges when conducting handling and stacking processes with conventional grippers during cell assembly. In this research, we present a parameter study on ASSB handling and stacking with PEO-based cell components aiming to promote process understanding and point out optimization potentials. An experimental design for testing different grippers is devised by which deposition accuracy was systematically assessed in relation to the holding force, gripper speed, and placement distance. Within this evaluation, the electrostatic gripper with PTFE dielectric provides adequate position and orientation accuracies in almost all experiments while showing improved accuracies with higher holding forces. Parameter settings achieving higher overall deposition accuracies for all tested grippers are identified. This research provides insights into the establishment of stacking processes for realizing an industry-scale ASSB production.