Interview with Antonia Stephenson, Cox Automotive
“A battery passport shouldn't replace assessment and diagnostics”
Antonia Stephenson holds a BA in Accounting and Finance from Newcastle University.
Cox Automotive Europe
Battery replacement costs are emerging as a critical factor for used-EV economics, residual values and customer confidence. Antonia Stephenson of Cox Automotive explains why the industry needs a repair-first strategy.
As the population of ageing electric vehicles grows, battery condition, repairability and lifecycle value are becoming increasingly important for the used-EV market. Antonia Stephenson, Director of Operations & Finance, EV Battery Solutions at Cox Automotive, works on the operational and commercial challenges surrounding EV batteries.
At Automotive Battery Conference 2026, she will present “Building a Scalable Battery Strategy – A Repair First Mindset” together with Russel Perry, Director of Engineering, EV Battery Solutions at Cox Automotive. Their session will examine the shift from range anxiety towards total cost of ownership, the role of battery repair and the risks for automotive brands when cost-effective solutions are unavailable after warranty expiry.
Ahead of the conference, we spoke with Stephenson about lifecycle value, battery diagnostics and the conditions needed to scale battery repair.
Automotive Battery Conference 2026 covers topics ranging from resilient supply chains and scalable manufacturing to battery safety, lifecycle value and charging. Which of these areas will shape the battery and e-mobility industry most over the next five years, and why?
Lifecycle value will be a defining issue in the industry over the next five years. As the number of used electric vehicles (EVs) grows, so too does the number of used EV batteries moving beyond manufacturer warranties. As a result, one of the most crucial challenges is how the industry supports a sustainable, circular approach to battery repair. For too long, the industry’s approach to a fault has been to send the battery straight to recycling and replace it with a new one. In the long run, this is neither cost-effective for consumers nor sustainable for the industry. Instead, we should be striving for an ecosystem that keeps batteries in circulation for as long as possible. It’s better from an environmental and financial perspective while also supporting a second-hand car market as EVs age. This is especially pertinent given the rapid pace of battery technology development, which means many direct replacements may not be available in the future.
Your agenda starts from replacement anxiety in the used-EV market. What single piece of evidence would most increase a buyer's confidence that an ageing battery can be safely repaired rather than expensively replaced?
A manufacturer-endorsed repair pathway would go a long way towards bringing greater confidence to the used market. Buyers want assurance that a battery has been independently assessed and deemed safe, with a clear track record of successful repairs to the battery, and that the technicians who carried out the work have been properly trained. Establishing a process that gives buyers visibility over all these factors would be a positive step forward for the used EV market.
With battery repair framed on the agenda as a missing link in a sustainable EV ecosystem, which pack design decisions most strongly determine whether repair is technically possible and economically worthwhile – joining methods, module access, diagnostics, sealing or software access?
Without accurate diagnostics and the right software access, repair is significantly more difficult regardless of the physical design. However, the most economically repairable batteries are those designed with repair in mind. These batteries are built with accessible modules, serviceable joining methods and approved resealing processes. So, if I had to choose one factor, it would be accurate diagnostics, but ideally, we want to see repair considered throughout the battery lifecycle. Ultimately, repairability is a design philosophy, not an engineering feature.
How do you determine whether a damaged battery should be repaired at pack level, opened for module replacement, repurposed or sent directly to recycling, and which diagnostic information is essential for that decision?
We can only make this decision once we determine if a battery can be safely handled. Assuming it can, we then start with accurate diagnostics to understand the fault, the likely cause and the remaining value within the battery. From there, we can determine the best technical, economic and environmental outcome. Our aim is always to place the battery at the highest point in the value hierarchy, starting with repair, then repurposing if repair can’t take place, with recycling as a final resort.
The Battery Passport session is immediately before yours. Which verified lifecycle data – state of health, damage history, repair events, ownership changes or usage data – are essential before a used EV battery can be judged safe, repairable and valuable?
While battery passport data can significantly improve confidence and decision-making, most of those data points aren't essential before a battery can be assessed. Today, many batteries are already being evaluated using a combination of physical inspection, diagnostic testing and battery management system data, often without access to a complete lifecycle record. What battery passport data does provide is context.
If I had to prioritise the most valuable information, it would be verified state of health, repair history and records of significant damage events, because they help us understand not only the current condition of the battery but also the risks and likely outcomes of repair. A battery passport shouldn't replace assessment and diagnostics; it should enhance them by providing trusted history alongside the technical evidence.
What currently limits the scalability of battery repair most: technical access, parts availability, technician skills, logistics, warranty rules, liability, diagnostic data or inconsistent pack designs?
There isn’t one universal constraint. In most cases, we can develop the technical capability to repair a battery if there's sufficient demand. The greater challenge is creating a system where repair can be performed safely, consistently and economically at scale.
If I had to highlight the biggest barriers today, I'd point to diagnostic data access, parts availability and liability. Without accurate diagnostics, it's difficult to identify the true root cause of a fault. Without a reliable supply of replacement components, even repairable batteries can become uneconomic. And without clear responsibility for the repaired battery's future performance, organisations can be reluctant to invest in large-scale repair programmes. Inconsistent pack designs also play a significant role. The industry has optimised batteries for performance, cost and manufacturability, but not always for serviceability. As a result, repair processes often need to be developed pack by pack rather than being broadly transferable across vehicle platforms.
Which other agenda topic intersects most with your own, and what would you ask that speaker or panel?
That’s a difficult question, as there are many sessions that link into what we are doing. However, if I were to pick one, it would be Architecting Trusted Mobility: Unlocking the True Value of EIS, as we are always looking for ways to improve our capabilities. One of the biggest repair challenges is accurately understanding a battery's true condition. Decisions on repair, reuse, repurposing and recycling are often constrained by the quality and granularity of the diagnostic information available. The better we can assess a battery, the more confident we can be in retaining value and avoiding unnecessary replacement. EIS has the potential to provide a much deeper understanding of battery health and degradation mechanisms than traditional diagnostics alone.
If we can identify issues earlier, isolate faults more precisely and improve our understanding of batteries’ remaining useful life, it could significantly increase confidence in repair decisions and help unlock greater circularity across the battery lifecycle. My question for Marc and the Analog Devices team would be: how close are we to seeing EIS evolve from a battery development and management technology into a practical diagnostic tool that can be used in service, repair and remanufacturing environments to assess repairability, predict remaining life and support decisions on whether a battery should be repaired, repurposed or recycled?
