The battery cell formation is one of the most critical process steps in lithium-ion battery (LIB) cell production, because it affects the key battery performance metrics, e.g. rate capability, lifetime and safety, is time-consuming and contributes significantly to energy consumption during cell production and overall cell cost.
In lithium-ion battery production, the formation of the solid electrolyte interphase (SEI) is one of the longest process steps. [ 1 ] The formation process needs to be better understood and significantly shortened to produce cheaper batteries. [ 2 ]
Figure 1 introduces the current state-of-the-art battery manufacturing process, which includes three major parts: electrode preparation, cell assembly, and battery electrochemistry activation. First, the active material (AM), conductive additive, and binder are mixed to form a uniform slurry with the solvent.
The formation and aging process makes up 32% of the total cost and can take up to 3 weeks to finish. The acceleration of formation will be eagerly embraced by the battery industry. However, the accelerated formation step cannot sacrifice battery performance.
Battery cell formation is part of cell conditioning. Cell conditioning also includes various quality test steps and quality sorting. The purpose of the formation process is to electrochemically activate the cell so that its subsequent performance is positively influenced. The formation process is critical for a number of reasons.
Volume 34, article number 1890, (2023) To become entirely operational, lithium-ion batteries (LIBs) must go through a formation process after assembly and electrolyte injection. To provide steady and repeatable cycling with the highest level of energy efficiency, a particular formation procedure is essential.