Fingerprinting for Rapid Battery Inspection

The technology utilizes photopolymer droplets (invisible to the digital radiograph) with embedded radiopaque fragments to create randomized fingerprints on battery samples. The droplets are deposited using a jig (see figure on right) that precisely positions samples. Then, at different points during battery R&D testing or use, digital radiography imaging with micron-level resolution can be performed. The high-resolution imaging required to detect dendrite formation requires images to be collected in multiple “tiles” as shown below. The randomized fingerprints uniquely identify relative positioning of these tiles, allowing rapid assembly of composite high-resolution images from multiple tiles. This same composite creation process can be used for images taken at a series of points in time during testing, and background subtraction can be applied to efficiently compare how the battery is changing over successive charge/discharge cycles to identify dendrite formation. This inspection technique is proven effective for thin-film pouch cell prototypes at NASA, and it works well at the lowest available x-ray energy level (limiting impact on the samples). The Fingerprinting for Rapid Battery Inspection technology is available for patent licensing. Dendrite growth in lithium-ion batteries can lead to fires and explosions, limiting battery life and safety. High resolution radiographs can be used to detect subtle precursors to battery failure, but it can be tedious to collect and combine these radiographs over the course of testing many battery samples. NASA researchers developed a novel technique for creating unique orientation fingerprints on battery samples prior to digital radiograph collection. The fingerprints enable rapid assembly of high-resolution images. This allows efficient inspection of batteries for early signs of dendrite formation, improving safety and extending useful battery life. This technology can improve efficiency in battery R&D, battery production, and other electronics applications.