High-speed imaging tests on batteries to help design safe enclosures on Navy ships

PHILADELPHIA –Engineers are using high-speed video of failing lithium-ion batteries to help design safe battery enclosures on ships, the Navy announced today.

When lithium-ion batteries fail, the cells may vent or explode, and if the resulting gas expands fast enough, a shockwave forms as it moves away from the battery.  Engineers at Naval Ship Systems Engineering Station, Naval Surface Warfare Center Carderock Division (NAVSSES) teamed with New Mexico Institute of Mining and Technology (New Mexico Tech) where researchers forced batteries to the point of failure in a laboratory environment to create a pressure release explosion.  They then used schlieren imagery, capable of capturing up to 250,000 frames per second, to make precise measurements of gradients in gas density near the failing cell. 

“We need to see what happens when the cell fails,” said Jason Ostanek, mechanical engineer with Energy Conversion Research and Development Branch at NAVSSES. “We have data from pressure transducers, but schlieren imaging will provide additional information, such as directionality of the blast.”

The high-speed imaging will also provide information such as shockwave speed versus position, and engineers can determine the track of any projectiles generated. These data will be compared to dynamic pressure gage measurements and parallel data generated at NAVSSES. The team hopes to quantify the amount of gas released, the gas release velocity, and identify the presence of any shock waves produced in the battery failures.

“Lithium-ion batteries are quite common – they are used in grid storage applications, electric vehicles, consumer electronics, a variety of military applications, and even formula-one race cars,” said Ostanek. “But the Navy will be using many batteries packed into enclosed spaces as part of the Multifunction Energy Storage Future Naval Capability (FNC). It’s crucial for us to understand what happens when a battery fails to know how it might affect other batteries in the space. Eventually we can use this data to develop lighter containers that can protect the other cells, while also being able to pack the cells closer together.”

Ostanek said engineers at NSWCCD and NSWC Crane routinely fail batteries to qualify them for use.

“We already know that lithium-ion batteries can meet power and energy requirements for our applications, but we also need to make sure they are being deployed in a safe manner,” said Ostanek.