Faulty battery cells can dramatically shorten battery life, increase warranty costs, affect customer satisfaction and damage product reputation, as well as create safety-and-drivability problems. 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. Depending on cell type, five percent or more of those cells may have undetected leaks. Leaks in lithium-ion battery cells can lead to serious safety and performance concerns when left undetected.
New technology from Inficon soon will allow automakers and battery suppliers to reliably test electric-vehicle battery cells for the first time. The breakthrough leak-detection systems can test all types of
lithium-ion battery cells for the first time in what is claimed to be the single most important leak-detection development in the past 10 years.
Developed at the company’s research facilities in Cologne, Germany, they also incorporate sensor technology from its North American headquarters in Syracuse, NY. Based on mass-spectrometer technology, the company’s new detectors are able to identify dangerous leaks 1000 times smaller than currently possible.
Only a fraction of new battery-cell leaks can be detected through traditional methods, said Dr. Daniel Wetzig, Inficon’s Research and Development Director for Leak Detection based in Cologne. He added that the company’s new ELT3000 could pave the way for the industry’s first reliable quality-control standards for EV battery cells.
The use of industry-first spectrometer technology, for example, can help assure an extended EV battery life of up to 10 years or more. The new systems also can be used to test billions of battery cells annually produced for use in smartphones, computers, and other consumer-electronics products. The technology was discussed in an SAE International paper published earlier this year called “Methods for Leak Testing Lithium-Ion Batteries to Assure Quality with Proposed Rejection Limit Standards.”
Better battery testing is more important now as demand for lithium-ion batteries is expected to increase dramatically over the next five to 10 years, according to Thomas Parker, Inficon’s North American Automotive Sales Manager.
“The global market for battery cells is expected to more than double from an estimated $44 billion this year to nearly $95 billion in 2025,” said Parker. “Annual lithium-ion battery-cell production in gigawatt-hours (GW·h) is expected to more than triple from 280 GW·h this year to 970 GW·h in 2025—equivalent to the hourly energy output of an estimated 1.9 million Corvettes, 1.3 billion horses, or 97 billion LED light bulbs,” Parker noted that by 2030 annual lithium-ion battery cell production is predicted to jump to more than 2600 GW·h.
EV car and light-truck manufacturers in particular are seeing significant growth in overall value and investor interest. Battery suppliers also are seeing surges in stock value with South Korea’s Samsung SDI and LG Chem up 35% to 50%, and China’s Contemporary Amperex Technology share price has climbed 50%.
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. Inficon equipment for testing prismatic and cylindrical cells is scheduled for introduction in October, followed by testing devices for pouch cells in late 2020 or early 2021.
Empty hard-case battery cells currently 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, 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 provides the reliably consistent results needed to establish industry-wide standards for battery-cell leak detection.
Inficon’s new process will allow automakers and battery suppliers to accurately test battery cells already filled with electrolyte. It can handle all types of common electrolyte solvents, including DMC (dimethyl carbonate) and EMC (ethyl methyl carbonate). The cells are placed into a vacuum chamber connected to an ELT3000 leak-detection unit with a mass spectrometer for testing. The equipment can be combined with a variety of automation technologies such as high-speed robotic assembly processes, but also can also be used in research and development laboratories.
