The Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut (EMI), has built a high-speed X-ray system that images the inside of large-format prismatic battery cells while they fail, recording up to 1,000 images per second. Fraunhofer EMI is now moving the technology into industrial use with PowerCo, the Volkswagen Group's battery cell manufacturer, which plans to install the system at its Salzgitter site in 2028.
The setup pairs high-performance X-ray hardware with a purpose-built battery test chamber and sensors that simultaneously log temperature, pressure, voltage, and gas flow. At full frame rate, it captures gas formation, material displacement, and crack propagation inside a cell as they happen. A key engineering hurdle was building a protective chamber that shields the X-ray components from the heat and pressure spikes of lithium-ion thermal runaway. "Our in-situ method allows us to see what happens inside a cell in fractions of a second, in real time and at the highest resolution," said Dr. Sebastian Schopferer, head of battery safety at Fraunhofer EMI. Engineers who currently piece together failure sequences from post-mortem teardowns or simulation runs will care about watching venting and crack growth unfold directly, without reconstructing it after the fact.
The system is not a lab prototype waiting for its first customer. Fraunhofer EMI has already used it with several German automakers, including Volkswagen and Audi, to characterize material ejection during thermal runaway and how failure propagates across multi-cell configurations. That data lets engineers evaluate cell designs against directly observed behavior and tune simulation models, feeding into product development and certification work.
In the next phase, Fraunhofer EMI supplies materials research, abuse-testing methods, and high-speed imaging expertise, while PowerCo contributes production requirements and access to real-world cell types. Initial results are already informing PowerCo's optimized production cells. The platform is modular, meaning it can scale to other cell formats and chemistries as battery designs change. "With in-situ high-speed X-ray imaging, we are taking battery research to a new level," said HW Vassen, CTO of PowerCo. The 2028 Salzgitter installation date marks the point where a research tool built for characterization work becomes part of PowerCo's regular production-development pipeline.
