INFICON, a leading supplier of automotive leak-detection technology, has authored an SAE International paper on advanced lithium-ion leak detection that could lead to the establishment of the industry’s first reliable quality-control standards for battery cells.
“There currently are no reliable tests on which to base leak-detection standards for a full range of soft-pouch, cylindrical or prismatic battery cells in use throughout the industry,” notes Dr. Daniel Wetzig, head of leak-detection research and development at INFICON. “Today’s pressure and helium testing methods are either too slow or unreliable, and also may allow small, but significant lithium-ion leaks to go unnoticed.”
He points out that INFICON has developed non-destructive leak-detection methods that for the first time can be used to set quantifiable and repeatable standards for testing all types of lithium-ion battery cells.
Lithium-ion battery cells fall into three categories – hard-cased prismatic and cylindrical cells and softer pouch cells. Because they are lighter in weight, pouch cells are growing in popularity with automakers, but they also are more difficult to accurately test.
Empty hard-case battery cells currently can be checked by filling the cells with helium test gas to detect leaks in a vacuum chamber. Electrolytes are not inserted into a hard-case cell until after it has been “dry tested.”
Helium bombing is an alternative approach. In this case, battery cells are placed in a vacuum chamber and exposed to helium under pressure. The helium is able to enter through existing leaks, then can be measured when it escapes back into the vacuum chamber.
Neither test method has provided the reliably consistent results needed to establish industry-wide standards for battery-cell leak detection.
Entitled “Methods for Leak Testing Lithium-Ion Batteries to Assure Quality with Proposed Rejection Limit Standards,” a print or digital copy of INFICON’s SAE Paper 2020 01 0448 is available at https://bit.ly/3dM6ht5 for $33. There is an 18 percent discount for SAE members.
INFICON is one of the world’s leading developers, producers and suppliers of instruments and devices for leak detection in air conditioning, refrigeration and automotive manufacturing. The company has manufacturing facilities in Europe, China and the United States, as well as sales and service offices throughout the world.