What are the recycling technologies for lithium batteries in the follow-up process?

At present, the recycling process of the common waste power battery includes two stages of pre-processing and subsequent processing. The pretreatment process first needs to be completely discharged, and then the battery is disassembled to separate the components such as the positive electrode, the negative electrode, the electrolyte and the separator. In the follow-up process, the main goal is to recover the high-value components of the dismantled waste materials and further rebuild or repair the battery materials; the technical methods adopted can be divided into three categories: dry recycling technology, wet recycling technology and biorecycling technology.

The dry recovery technology refers to a technical method for directly recovering various types of battery materials or valuable metals without passing through a medium such as a solution, and mainly includes a mechanical sorting method and a high-resolution pyrolysis method. The dry recovery does not undergo other chemical reactions, the process is short, and the recovery is not targeted, and is usually used in the preliminary stage of separation and recovery of metals in lithium batteries.

Some enterprises have initially developed dry heat repair technology, which can perform high temperature heat repair on the crude products recovered by dry method; however, the positive and negative materials produced by this method contain certain impurities, and their performance cannot meet the power of new energy vehicles. The requirements of the battery are mostly used in scenes such as energy storage or small power batteries.

The wet recovery technology uses various acid-alkaline solutions as a transfer medium to transfer metal ions from the electrode material to the leaching solution, and then ion-exchange, precipitation, adsorption, etc., to remove metal ions in the form of salts, oxides, and the like extracted from the solution. The wet technology route mainly includes three methods of hydrometallurgy, chemical extraction and ion exchange. The wet recovery technology is relatively complicated, but the technology has a high recovery rate for valuable metals such as lithium, cobalt and nickel. At the same time, the high purity of metal salts and oxides obtained by the wet recovery technology can To meet the quality requirements of the production of power battery materials; therefore, the wet recycling technology is also the main recycling method adopted by leading technology recycling companies at home and abroad.

The biorecovery technology mainly utilizes microbial leaching to convert useful components of the system into soluble compounds and selectively dissolve them to separate the target components from the impurity components, and finally recover valuable metals such as lithium, cobalt and nickel. At present, the biological recovery technology is not yet mature, such as the cultivation of high-efficiency strains, the long culture period, and the control of leaching conditions remain to be solved.

As mentioned above, the current recycling process with higher recovery efficiency and relatively mature is becoming the mainstream technical route in the professional processing stage; the leading domestic enterprises such as GEM, Bangpu Group, and most leading international companies such as AEA and IME. The wet technology route is adopted as the main technology for the recovery of valuable metal resources such as lithium, cobalt and nickel; some enterprises also support various recycling technologies such as dry method to improve the comprehensive recovery efficiency.

On the other hand, for both lithium iron phosphate and NCA ternary materials, the specific capacity, a key performance index of the cathode materials obtained by wet method after recovery of valuable metals, is superior to that obtained by dry method.

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