DETROIT – More than 80 percent of all automotive leak testing relies on out-of-date methodology. Water-bath tests have been used in the auto industry for more than 125 years for example, but are not suitable on today’s production lines. Modern assembly lines require faster and much more accurate methods to ensure quality.
Although it’s important to have accurate equipment when leak testing automotive components, it’s just as important to understand what types of tests should be administered. This is even more important as we move farther into the era of electrification and battery-powered vehicles.
Tire Water Bath
As the EV market expands, it is critically important to leak test battery packs, battery cells and cooling circuits to ensure that they keep water out and electrolyte in.
Placing a bicycle tire or tube in water to look for bubbles might work for these parts, but submerging an EV battery pack in water is impractical, time consuming, inaccurate and could even be dangerous.
Today, helium and forming gas such as a safe 5% hydrogen/95% nitrogen mix have replaced water and pressurized air to provide more accurate, repeatable tests under a variety of temperature and humidity conditions. This is especially important with EV battery packs, battery cells and cooling circuits to help automakers avoid costly warranty costs, customer service issues or safety-related problems such as fires or explosions.
Battery cells initially are assembled into battery modules, which then become battery packs. Battery-pack housings must protect the internal modules and cells from water and conform to IP67 or IP69K protection ratings.
If battery-cell electrolyte reacts with water, hydrofluoric acid is produced, which will damage the battery cell. That is why even the smallest components of a traction battery – the battery cells – must be air and water tight. Reliable gas-tightness can only be verified by modern test-gas methods, for example by helium testing in a vacuum chamber.
Air-pressure testing of the cooling circuit can’t be relied upon to ensure that the system’s ethylene glycol coolant won’t leak into the high-voltage circuitry of a battery pack. Sniffer leak detection with test gases, which is often carried out automatically with a robotic arm, is recommended for this purpose.
As a partner with the automotive industry, INFICON is digging deeper to educate customers on the best methods for leak testing their battery packs and cooling components.
For more information on leak testing in general, visit www.INFICON.com. To download an e-mobility white paper about concerns of leak testing EV battery packs, cells and cooling systems, download it from the following link: https://www.inficon.com/en/markets/automotive/e-mobility-white-paper/
To view a video of Parker talking about INFICON leak detection technology, click on https://youtu.be/-jfFy_v-pHg
About the Author
Thomas Parker is responsible for INFICON’s automotive sales in North America, supporting the company’s growing focus and investment in the automotive market. Parker previously had been the company’s leak-detection segment manager for the eastern United States. He joined INFICON in 2006 as a key account manager in Atlanta. Prior to that, he served as a technical sales representative at W.L. Schoonover Inc. in Canton, Georgia.