New Tech Offers Reliable EV Battery-Cell Testing For First Time

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New technology from INFICON soon will allow automakers and battery suppliers to reliably test critically important electric-vehicle battery cells for the first time.

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.

INFICON's breakthrough leak-detection systems can reliably and accurately test all types of
lithium-ion battery cells for the first time – 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 INFICON's North American headquarters in Syracuse, New York.

Based on mass-spectrometer technology, the company's new leak detectors are able to identify dangerous leaks 1,000 times smaller than currently possible.

Dr. Daniel Wetzig, INFICON's research and development director for leak detection based in Cologne, notes that only a fraction of new battery-cell leaks can be detected through traditional methods. He adds that the company's new ELT3000 technology also 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," Wetzig says. "The use of industry-first spectrometer technology, for example, can help assure an extended EV battery life of up to 10 years or more."

He points out that INFICON's new systems also can be used to test billions of battery cells annually produced for use in smart phones, computers and other consumer-electronics products.

INFICON's breakthrough technology was discussed for the first time in an SAE International paper published earlier this year. Entitled "Methods for Leak Testing Lithium-Ion Batteries to Assure Quality with Proposed Rejection Limit Standards," a print or digital copy of the paper is available from SAE.

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," Parker points out, adding that  "Annual lithium-ion battery-cell production in gigawatt hours (GWh) is expected to more than triple from 280 GWh this year to 970 GWh 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 notes that by 2030 annual lithium-ion battery cell production is predicted to jump to more than 2,600 GWh, equal to the hourly output of 5.2 million Corvettes, 3.3 billion horses and 260 billion LED light bulbs.

EV car and light-truck manufacturers in particular are seeing significant growth in overall value and investor interest. Tesla's market cap in July actually passed Toyota's more than $200-billion cap to make Tesla the world's most valuable car company.

Rivian, the U.S.-based EV truck and SUV startup, has secured $5.3 billion in investment capital since last fall to help launch three new vehicles in 2021.

Battery suppliers also are seeing surges in stock value with South Korea's Samsung SDI and LG Chem up 35 to 50 percent. China's Contemporary Amperex Technology share price has climbed 50 percent as well.

Although China recently imposed tougher production standards for batteries, Thomas does not believe government regulations will drive future quality control improvements in the auto industry.

"Automakers in North America, Europe and the Asia Pacific region want to maintain high quality standards and customer acceptance levels for their future wave of electric vehicles," Parker explains. "Car companies will have the most to lose if their batteries can't achieve mileage targets, require early replacement or cause safety concerns."

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, 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 provides the reliably consistent results needed to establish industry-wide standards for battery-cell leak detection.

INFICON'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.

Wetzig adds that INFICON's new systems are designed to handle all types of common electrolyte solvents, including DMC, EMC and PP, as well as many others.