This review examines the key process of lithium-ion battery cell formation. Influencing factors, challenges, experimental and simulation tools required for knowledge-based process design of current and emerging battery technologies are addressed.

The cell finishing process is the final stage in the production of a battery cell. Almost one third of the production costs of a battery cell are related to this part of the production. It includes a series of steps and technologies aimed at optimizing the battery cell’s performance, quality, and safety. The process is divided into three categories: pre-treatment, formation procedure, and quality testing. The order of the processes and the time required for each step can vary depending on the manufacturer and the cell format. Recent trends in optimizing the cell finishing process include the integration of a second filling process for larger prismatic cells and the optimization of the formation protocol or Electrochemical Impedance Spectroscopy (EIS) as possible methods for quality inspection. Efforts are also being made to reduce the pre-treatment time and improve the degassing process to ensure cell performance, quality, and safety. In this paper, all process steps of the cell finishing process are presented, and their function and technological implementation in the industry are explained. Future innovations are analyzed in terms of time to market and the potential to optimize the process in terms of quality, time, and cost.

Zusammenfassung: Die Bereitstellung der elektrischen Antriebsenergie erfolgt in batterieelektrischen Fahrzeugen (BEV) derzeit überwiegend durch Lithium-Ionen-Batteriesysteme. Diese Systeme bestehen aus Batteriemodulen und Batteriezellen in unterschiedlichen Formaten. Das Batteriesystem ist dabei eine Schlüsselkomponente des Elektrofahrzeugs und beeinflusst maßgeblich die Reichweichte sowie die Performance. Außerdem macht das Batteriesystem einen Großteil der Kosten von heutigen Elektrofahrzeugen aus. Um im internationalen Wettbewerb langfristig erfolgreich zu sein, müssen Hersteller von Elektrofahrzeugen daher bereits in der Entwicklung und Produktion von Batteriesystemen Qualitäts- und Kostenpotenziale ausschöpfen. Darüber hinaus wird eine nachhaltige Produktion von Batteriezellen, -modulen und -systemen besonders in Europa in den kommenden Jahren immer wichtiger.