The process of processing negative electrode materials - Bolu Tiancheng

The production process of negative electrode materials is long and there are many types of raw materials, so negative electrode factories have certain bargaining power. The processing of artificial graphite negative electrode materials requires a long process for particle size and morphology design, including pretreatment, pyrolysis, ball milling, outsourced graphitization, screening, and other steps.

In the production process, the composition of negative electrode material products is relatively complex, including various types of coke and additives. Battery companies usually cannot fully grasp the complete cost of artificial graphite suppliers, so the negotiation ability of artificial graphite suppliers is relatively strong compared to other material links.

The technology route of artificial graphite negative electrode is relatively mature, and more barriers are concentrated in the granulation process. The theoretical specific capacity of artificial graphite is 372mh/g, and currently mainstream products can achieve 345-355mh/g. Its production process involves crushing, granulation, graphitization, and screening of aggregates and binders. Compared to the crushing spheroidization mixing sieving magnetic separation process of graphite negative electrodes, artificial graphite negative electrodes have three key processes: granulation graphitization and secondary granulation. The basic process flow of each is the same, but there may be some differences, such as carbonization and modification, screening times, etc. 

Relatively speaking, the various processes of artificial graphite negative electrode are relatively mature in technology, so it is more about process optimization and cost comparison. During the granulation process, the size, distribution, and morphology of graphite particles have a significant impact on the negative electrode performance indicators. Enterprises need to balance the advantages of small particles in rate performance and cycle life, as well as the disadvantages in efficiency and compaction density, while also weighing the impact of particle morphology on rate performance and low-temperature performance; Artificial graphite is generally subjected to secondary granulation after graphitization, where 7-8 small particles are bonded together to balance expansion performance and density.

Graphitization is an extension of the traditional carbon industry, and therefore leading companies in the negative electrode industry, such as Hitachi Chemical and Mitsubishi Chemical. Currently, graphitization technology is mature but has a significant impact on cost control. Artificial graphite usually uses warm graphitization processes, which have higher costs.