About Featured Expert: ReJoule
ReJoule are industry experts in battery diagnostics, state-of-health assessment and rapid testing technologies for electric-vehicle and stationary-storage batteries. The company develops hardware and analytical software that help battery manufacturers, service organizations, remanufacturers and second-life operators understand what a battery can still reliably do. That question becomes increasingly important as electric-vehicle batteries move through service, repair, reuse and eventual recycling.
Traditional battery-capacity testing can require lengthy charge-and-discharge cycling. ReJoule takes a different approach, using electrochemical impedance spectroscopy to measure how a battery responds to small electrical signals applied across multiple frequencies. The resulting data can reveal changes in internal electrochemical behavior that cannot be determined from voltage, mileage or state of charge alone. ReJoule combines those measurements with battery-specific analytical models to estimate state of health. Its BattScan systems perform the physical testing, while BatteryDB records and processes the results across larger battery populations. This creates a more structured and consistent view of battery condition, rather than leaving each test as an isolated measurement.
That distinction matters most when a battery reaches a decision point. A used EV pack or module may still retain significant capacity, but capacity alone does not determine whether it is suitable for continued vehicle use, repair, stationary storage or recycling. Operating history may be incomplete, and batteries from the same vehicle population can show meaningful differences in condition.
ReJoule provides the diagnostic information needed before those decisions are made. Its systems can evaluate batteries at the module and pack levels, and selected configurations can test high-voltage EV batteries through the vehicle’s DC fast-charging connection.
The company demonstrated this approach in a battery-repurposing project conducted with Renewance. ReJoule tested 1,670 lithium iron phosphate modules recovered from retired electric delivery trucks using its BattScan050M system. Each module was tested in approximately five minutes, with the results processed through BatteryDB.
The published study reported a median absolute state-of-health estimation error of 2.9%. That result applies specifically to the battery population and model used in the project, but it provides a useful example of how rapid impedance testing can support large-scale battery grading without requiring every module to undergo a full cycling test. The same diagnostic foundation can be applied much earlier in the battery lifecycle. Within manufacturing, impedance measurements can add another layer of information to end-of-line quality assessment. In service and remanufacturing environments, battery-condition data can support inspection, warranty review and decisions about module or pack repair.
At the end of a battery’s first application, that information becomes part of the wider circularity decision. Some batteries may remain suitable for transportation use. Others may be better matched to stationary energy storage, while batteries with insufficient remaining condition can be directed toward recycling. ReJoule does not reduce those decisions to a single number. Its value lies in providing a faster, more consistent and more technically grounded view of battery condition, allowing engineering, service and asset-management teams to make better-informed decisions about what should happen next.
Typical applications for ReJoule technologies include electric-vehicle battery service, warranty assessment, pack remanufacturing, end-of-line quality control, second-life battery grading, stationary-storage qualification and recycling intake.
Based in Signal Hill, California, ReJoule develops battery diagnostic hardware, analytical software and testing services for organizations managing batteries across their first and subsequent operating lives. To learn more about ReJoule and its battery diagnostic technologies, please click here.
(Editor’s Note: All trademarks mentioned in this article, including company names, product names, and logos, are the property of their respective owners. Use of these trademarks is for informational purposes only and does not imply any endorsement.)
Molly Bakewell Chamberlin is the Founder, Publisher and Editor-in-Chief of Components Source Network, a 100% woman- and disability-owned B2B publishing and expert marketplace platform serving the global high-tech manufacturing and engineering community. She is the architect, author and developer of the Network’s 11 specialized e-news sites and 11 peer-vetted expert e-marketplaces, including EV + Battery Tech Monthly. With more than 25 years of experience in strategic technical marketing, public relations and business development, she is also the Founder and President of Embassy Global, LLC, which has supported more than 200 high-tech industry brands worldwide since 2008. Molly also serves pro bono as Second Vice Chair of the Government Team for the WBENC Forum and is a long-standing advocate for small business, supplier diversity, sustainability and women in STEM. Connect with Molly on LinkedIn.
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