The need for continuous development and deployment of reliable energy storage devices such as Lithium-ion rechargeable batteries has become increasingly crucial for EV transportation modes. In recent years, the EV industry has seen numerous developments in Cathode Active Materials (CAM) to improve their structures and properties. These materials affect battery performance in energy and power densities, cycle life, and safety.
The positive electrode, the cathode, consists of a highly pure mixture of lithium metal oxides. The more uniform its chemical composition and crystal structure, the better battery performance and life are. The CAM production process is complex and requires multi-chemical transformation stages involving solid, liquid and gaseous products to get a pure mix of active materials. Unsurprisingly, QA controls are also becoming more and more stringent for chemical companies as CAM quality impacts the overall performance of the battery itself and its cost per KWh. To meet the EV battery manufacturers’ specifications, high-performance filtration solutions are required at the different fabrication stages to produce pure and uniform cathode active materials.
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Challenge
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Solution
For its new manufacturing plant, a major chemical company wanted to install appropriate filtration solutions on its processing lines to help produce high-energy cathode active materials. To achieve this goal, the company needed to raise the bar regarding process control to supply EV battery manufacturers with CAM featuring a high degree of purity and excellent product characteristics. The chemical company conducted preliminary feasibility and definition studies for its production facilities, representing more than 30 processing lines, including liquid and gaseous utilities.
Fine filtration required at the different stages of the production of the NMC cathode active materials for lithium-ion batteries
The filtration and separation solutions provided were mainly driven by the operating conditions of the different processing lines and the micron rating required to achieve the right degree of purity, considering the very narrow size distribution of the active material. Depending on the processing line, single or multi-element and simplex or duplex stainless-steel vessels were selected to ensure the best filtration performance while minimizing the total cost of ownership.
As a general overview, the technologies below were selected for use:
- Pall Ultipleat® High Flow (CAS series – 1 µm) on NiSO4, MnSO4, CoSO4, NaOH and SO4 pure diluted or mixed solutions
- Pall Profile® Coreless 0.3 µm on utility lines (Nitrogen, Oxygen, Compressed air)
- Pall Poly-Fine® II or Pall Varafine® VFTR 0.45 µm on solvents and carbonate solutions (DMC, DEC, EC, PC). In addition to these filter families, various liquid and gas filter elements and ceramic membranes were installed on several processing lines.
Functional Principle of a Lithium Battery
Conclusion
Pall partnered with the chemical company to select the optimal filtration and separation technologies and solutions to install in its new manufacturing plant to deliver high-quality cathode active materials to EV battery manufacturers. More than 30 processing lines, including utilities, were equipped with high-performance filters (down to 0.3 µm filter rating). Several different configurations of vessels were used on the processing lines to minimize the cost of ownership, ensure continuous production and simplify the maintenance operations.
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