This robot quickly and efficiently detects leaks on a lithium-ion battery. (Inficon)
Detecting battery leaks at production speeds
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Inficon has launched what it said is an industry-first, robotic-compatible leak-detection system that can use either helium or hydrogen-forming gas to ferret out minuscule cracks in the batteries of electrified vehicles.
“Customers were asking for an accurate and reliable high-speed leak detector that could use both tracer gases so they could choose the lowest-cost or easiest-to-source test gas available,” said Thomas Parker, a mechanical engineer and Inficon’s North American automotive sales manager. The leak detector has the same testing sensitivity with either helium or the forming gas (95% nitrogen/5% hydrogen).
The XL3000flex can detect small leaks up to 20 times faster than conventional systems. Inficon’s testing unit uses sample gas flows of 300 or 3000 sccm (standard cubic centimeters per minute) versus the typical sample gas flows of 60 to 150 sccm with existing leak detectors.
“A 60 to 150 sccm detection rate is much too slow to meet typical production cycle times, but a selectable 300 or 3000 sccm is ideal for robotic applications that need a high sample-gas flow for reliable testing, ” said Parker. With a gas flow of 3000 sccm, Inficon’s system can detect leaks of 10 -3 mbar per liter a second at a distance of 6 mm (0.23-in) during scan speeds of 10 cm (3.93-in) per second, according to Parker. The XL3000flex is a self-contained unit employing a magnetic sector mass spectrometer and patented software algorithms.
One alternative to tracer gas testing is a method in which parts are pressurized and fluctuations in pressure indicate a possible leak. “The problem with today’s pressure decay testing is that pressure changes can also be caused by temperature changes. So a pressure drop does not always indicate a leak, and a pressure increase can mask a leak,” noted Sandra Seitz, global market manager for Inficon’s automotive leak detection tools.
Any undetected battery leak can spur dangerous outcomes.
A battery cell leak can lead to an intake of air humidity, which will create sulphuric acid inside the cell, explained Seitz. “It’s a situation that means a loss of battery capacity and it could evolve to a worse-case scenario of thermal runaways that cause a burning battery,” she added.
Troubles also can manifest if water seeps inside the battery housing via an undetected leak. “The water intake could destroy the battery itself or destroy the battery management system and lead to uncontrolled operation of the battery resulting in overheating or a fire,” noted Seitz.
A cooling system leak is also problematic if the cooling liquid, typically a glycol-water mixture, reaches the electronics. If an electrical short results, a loss of cooling and overheating of the individual cells is likely, according to Seitz.
Current production applications of Inficon’s XL3000flex include testing on fully assembly battery packs as well as leak detections on automatic transmissions and high-pressure GDI fuel systems. “The XL3000flex is Industry 4.0 production-ready with an easy-to-use ethernet IP communication protocol, enabling the customer to capture more data during testing,” said Parker.
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