As a matter of fact, among the markets that we have been providing solutions to, the lithium-ion battery industry and its raw materials suppliers started to use Entegris technologies around 2005-2006, whether it be at the cell fabrication stage or at the chemical manufacturing plant, when it became clear that contamination could have a significant impact on batteries’ reliability.
To provide solutions to the LiB players, Entegris has been using approaches based on the comparison with processes in the semiconductor industry and adapted to this market, as their needs are not always the same.
The various process steps in LiB manufacturing, and their environment, have been thoroughly studied to either implement existing solutions or develop new ones. Among these solutions, aqueous or organic solvent filtration can be proposed at the mixing step, as well as water removal from organic solvent. Improving the coating process presents a challenge, though since formation of aggregates or other problems related to slurry properties are difficult to handle; within this step, the use of a high viscosity pump to transfer the slurry to the slot die or filtration to remove aggregates can be implemented. Even if it is well known by most of the manufacturers, reducing the HF concentration in an electrolyte is important to improve cycling performances. At the cell filling stage, purifiers to reduce HF and H2O from the electrolyte have been developed.
Generic plant layout extracted from Entegris commercial brochure
Through the ELIBAMA project, Entegris aims to develop and validate novel separation technologies with specific Contaminant/Matrix couples that have not been previously investigated elsewhere (like HF removal from organic based electrolytes).
Determining the nature and source of the contaminants is key to improving battery performances in term of capacity, cycling life and safety issues. Entegris is closely working with SAFT to determine the contamination brought by the different sources: raw material, human factor, environment and process during the battery cell manufacturing. In the course of the program, the audit performed by Entegris and SAFT to improve product quality at the various manufacturing steps provides a fruitful collaboration that helps both partners to understand the impact of many variables on the process.
As a second step, solutions proposed by Entegris may be implemented on production lines and new processes will be explored together with Renault. This initial collaboration between Renault, Saft and Entegris is crucial to the project, and it is anticipated that expanding this investigation on the impact of contamination will help other partners to contribute to improving batteries performance.
Christelle Herriot (Entegris)