Confidence in battery health will be vital in supporting more consumers switch to pure electric vehicles in the years ahead, and the industry must become adept at identifying underperforming cells and restoring battery health to optimal levels writes Dr Sara Ridley, engineering and quality director at Autocraft EV Solutions, part of Autocraft Solutions Group.

As the transition to electric gains momentum, several important obstacles must first be eliminated if EV is to truly become a viable alternative to the internal combustion engine (ICE). 

While much of the discussion tends to focus on factors like range anxiety and charging infrastructure, our ability to accurately measure, monitor, and improve EV battery State of Health (SoH) merits particular attention, as illustrated by the Labour party’s recent announcement that it would introduce standardised battery “health tests” to give confidence to buyers of second-hand EVs. Our success in this area will have a major bearing on this transition, overcoming the perceived risks of EV ownership while unlocking the environmental benefits. Here we examine the crucial role of testing and the importance of EV battery health transparency.

Instilling confidence within the used EV market

Most people are familiar with how a healthy ICE vehicle should look and sound, and could easily access a second opinion if necessary. Having confidence that what you are buying is what you are going to get is critical, and yet, there are considerably more unknowns when it comes to buying an EV. 

Our experience in EV battery repair has found many SoH assessments from vehicle battery management systems to be quite inaccurate. We’ve seen many an EV battery performance issue that hasn’t been picked up by the BMS, simply because the testing methodology doesn’t go into sufficient depth. Because of this, many problematic cells and potential faults go undetected, which raises question marks around the actual state of health of the battery and the degree of risk attached to it. 

The vast majority of people who buy vehicles buy them second-hand, and when they can’t be confident about what they are getting, demand for used EVs is going to remain low, creating huge disparities in value between new and used. In turn, weak residual values for used EVs will make leasing a more attractive option for buyers, who will turn to leases. Leasing companies, for their part, will be forced to drive up their costs to offset the drop in residual values. Without instilling confidence in used EVs, the entire market suffers. Multi-layer testing represents the best available option to instil confidence, providing a more in-depth picture of battery health, potential issues, and their root causes.

Informed decisions around repair

A multi-layer test can reveal battery health on an individual cell level. If an EV battery only performs to the level of its weakest cell, identifying underperforming cells is the first step to restoring optimal battery health. Moreover, the use of digital twins provides us with a reference for typical battery health given where the battery is at in its life cycle, allowing us to identify outlier cells that are at risk of future failure. These insights are based on comparisons with thousands of data sets accumulated through years of battery repair. 

The implications of this are huge – whether for OEMs, for in-warranty repairs, or the growing numbers of vehicle owners no longer protected by warranty, they will be able to make more informed decisions about the extent of proactive battery repair work. For instance, we can now accurately predict the improvement in performance by replacing a single faulty cell with a healthy replacement. We then contrast this benefit with the potential improvement from replacing multiple cells, allowing the customer to weigh up the costs and benefits in order to decide on the best course of action. Prevention is better than the cure, and testing can support a proactive approach to maintaining optimal health.

Unlocking the environmental benefits of EV batteries through remanufacturing

Given the well documented environmental cost of producing EV batteries, we have a duty to extract maximum value from every cell by ensuring they remain in use for as long as possible. For all the talk of EV battery recycling, the technology still has clear limitations. Because of the substantial, less publicised environmental impact of recycling, we should only recycle EV battery modules or cells once all available options to repair and re-use have been exhausted. 

With the right level of testing, we can assess the health of individual cells within a faulty unit that may be unviable for repair e.g., if the vehicle has been involved in a crash. Following this approach, we can extract healthy cells and parts and keep them in stock until they can be re-used in future, helping to keep other vehicles on the road for longer. Given the speed at which EV battery chemistry is evolving, the future repairability of say, a five-year-old vehicle, will depend on the availability of these parts. Without the ability to accurately gauge the health of cells and balance them within a new pack, the environmental benefits are severely compromised.

Author: Dr Sara Ridley, engineering and quality director at Autocraft EV Solutions, part of Autocraft Solutions Group