Vacuum applications in battery production

Safety concerns and costs of cell failure to battery manufacturers drive the search for reliable test methods to ensure leakage-free battery cells. However, there are currently no standardized test methods used in battery industry to find leaks at cell level.

In this study, a series of pouch cells were made with and without deliberate defects to investigate the combination of a preliminary leak test with a subsequent gas analysis with respect to a reliable detection of defective cells. For the leak test a mass extraction instrument ME4 was used which allows to correlate the flow rate to the defect size. Mass extraction is a test method capable of identifying battery cells that have defects common in high-volume cell manufacturing. In addition to the leak test the OmniStar, a self-contained gas analysis system, was used to continuously measure gasses and vapors up to 300 amu with speeds in the sub 1 second range in order to monitor if components of the electrolyte are leaking out of the cell. This eliminates concerns by unnecessary lost production by rapidly verifying that a failed mass extraction test is due to electrolyte leaking out of the cell.

Herein, we report that the combination of these two methods can be used to provide a robust solution to the costly and unsafe problem of leaking battery cells which minimizes assembly line down times.