EV battery leak detection tech promises reliable Li-ion testing
The company says its breakthrough leak-detection systems can reliably and accurately test all types of lithium-ion battery cells for the first time – claimed to be the single most important leak-detection development in the past 10 years. Billions of lithium-ion battery cells are produced annually for use in electric, hybrid-electric and autonomous vehicles, as well as for medical devices and a variety of consumer electronics products, and depending on cell type, five percent or more of those cells may have undetected leaks, says the company.
Based on mass-spectrometer technology, the company’s new leak detectors are offered as being able to identify dangerous leaks 1,000 times smaller than currently possible. Only a fraction of new battery-cell leaks can be detected through traditional methods, says the company, and its new ELT3000 technology could pave the way for the industry’s first reliable quality-control standards for EV battery cells.
“The rapid detection of even the smallest battery-cell leaks is absolutely essential to achieving extended service life and meeting necessary safety requirements,” says Dr. Daniel Wetzig, INFICON’s research and development director for leak detection. “The use of industry-first spectrometer technology, for example, can help assure an extended EV battery life of up to 10 years or more.”
Three types of battery cells today are used to power most hybrid-electric, electric and autonomous vehicles: hard-cased prismatic, cylindrical cells, and softer pouch cells. The company expects its equipment for testing prismatic and cylindrical cells to be introduced in October, followed by testing devices for pouch cells in late 2020 or early 2021.
Currently, says the company, empty hard-case battery cells are checked by filling the cells with helium test gas to detect leaks while in a vacuum chamber. Electrolytes are not inserted into the cells until after they have been “dry tested.”
“Helium bombing” is an alternative approach, but generally not suited for liquid-filled components. If used, however, electrolyte-filled battery cells are placed in a vacuum chamber and exposed to helium under pressure. Helium enters through existing leaks and then can be measured as it escapes back into the vacuum chamber.
Neither test method, says the company, provides the reliably consistent results needed to establish industry-wide standards for battery-cell leak detection. The company’s new process will, for the first time, allow automakers and battery suppliers to accurately test battery cells already filled with electrolyte: The cells are placed into a vacuum chamber connected to an INFICON ELT3000 leak-detection unit with a mass spectrometer for testing.
The INFICON equipment can be combined with a variety of automation technologies such as high-speed robotic assembly processes. It also is available for use in research and development laboratories. The new systems are designed to handle all types of common electrolyte solvents, including DMC, EMC and PP, as well as many others.
In addition to EV batteries, says the company, its new systems can also be used to test billions of battery cells annually produced for use in smartphones, computers, and other consumer electronics products. For more, see “Methods for Leak Testing Lithium-Ion Batteries to Assure Quality with Proposed Rejection Limit Standards.”
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