Improving EV Battery Reliability with the Right Battery Data

Four ways EV data can deliver insights that help manufacturers respond to recalls and improve future battery design 

In recent years, battery-related recalls have stymied the rollout plans of electric vehicle models from an array of global carmakers — the cost of which can range from tens to hundreds of millions of dollars and include deep reputational wounds for brands. Reducing the rate and impact of these recalls requires thoroughly understanding the reliability and performance issues that EVs and their traction batteries endure during use and the conditions that cause them. 

Many original equipment manufacturers (OEMs) are turning to the EV data their fleets produce for insights. While some OEMs are just beginning to capture data en masse, others are sifting through mass quantities. In both scenarios, knowing what data is most useful and how to use it can help you get ahead of potential performance vulnerabilities — instead of finding out about alleged problems from complaints in the market or field failures. 

Efficiently capturing and analyzing the available data from a fleet of vehicles is a monumental task, but when done right, it can be used to capture significant benefits throughout the vehicle design lifecycle.

Finding value in mass EV battery data 

Advanced monitoring systems that periodically check and provide information on the health of connected EV battery packs are a powerful, evolving source of data for OEMs. These systems can help stakeholders spot short-term hazards, such as weak battery cells, which can be used to mitigate field issues before they become long-term problems. These same battery monitoring systems can also be used to improve future iterations of an EV battery and deploy proactive strategies, such as optimal conditions for fast charging, that have been trained on real-world performance data. 

Whether an OEM is in the early phases of development or seeking to optimize their data analysis architecture, fleet-level data holds transformative potential. By fully exploiting the data streams from EV traction batteries, stakeholders can unlock insights across the full product lifecycle. 

Here are four ways getting the data right can help improve battery performance and reliability. 

1. Improve EV battery design  

Battery packs are the costliest components of EVs, and they heavily influence consumer perception of the entire vehicle. Thus, battery pack design engineers are deploying advanced techniques, such as using prototype testing and performance field data, to identify inefficiencies in current designs, develop customized solutions for future battery pack development, and improve battery pack performance for the consumer.

Collecting and analyzing field data to identify opportunities for improving battery pack performance sounds straightforward. However, developing and implementing a process to effectively capture, distill, and process the terabytes of information that can come from each vehicle is non-trivial. Continuously analyzing the data from thousands of vehicles at once further magnifies the challenge. 

Artificial intelligence and machine learning are evolving quickly and supporting OEMs in efficiently distilling the results from vast vehicle networks into actionable improvements. However, fully capturing the capabilities of these technologies means knowing how to feed them the right information and interpret their results to surface actionable insights. OEMs can take steps toward accelerating the use and development of AI/ML tools in the context of batteries through a strong understanding of complex battery dynamics, including minute chemical changes within the battery cells. 

Assessing the battery pack performance of in-market vehicles can also help accelerate the feedback loop of fleet-level data to surface opportunities for improvements in pack design. In particular, this data can be used to improve performance parametrics such as charging times, range estimation, and battery life by identifying and mitigating failure modes at their earliest stages.

2. Adopt continuous monitoring to spot tiny changes in EV battery performance

As EV adoption grows, the growing number of on-road miles driven by EVs will be a critical source of data and insights into charging and discharging behavior and trends over the lifetime of an EV fleet. Continuous, real-time monitoring and analysis of battery pack data such as charge and discharge characteristics, cell balancing activity, thermal management operations, and fault diagnosis can identify predictive maintenance strategies or support deploying alternative charging and discharging strategies. 

These adjusted control parameters can be administered through on-board programs or periodic software updates that may not require any action from EV owners. Analyzing EV battery data effectively requires expertise on the battery pack's degradation and failure modes to better implement required maintenance solutions. For example, if a battery pack's driving range is deteriorating at an accelerated rate, understanding the primary factors that are contributing to the degradation is essential to defining the right mitigating actions.

3. Respond to potential incidents quickly and effectively 

In the event of a vehicle fire or thermal runaway event, continuous monitoring of EV battery pack data may also prove crucial to the speed and results of a root-cause analysis. According to a 2023 report compiled by the National Transportation Safety Board and Bureau of Transportation Statistics, fully electric cars (not hybrid) stand a .03% chance of igniting compared to the 1.5% chance of internal combustion engines; however, EV fires often draw additional publicity — and pose unique challenges for forensic engineering investigations.

When EV fires do happen, the intensity of the thermal event and common containment processes can be destructive to the battery pack and the rest of the powertrain. As a result, determining the root cause of the failure can be more difficult relative to conventional vehicles, as extensive damage from the event often obscures evidence. 

Manufacturers who invest in robust battery data monitoring and connectivity are likely better equipped with actionable data to work from, which can lead to determining the root cause of the failure more quickly. When properly designed, such as through effective data storage or transmission, acquiring and analyzing battery-related data can enable EV manufacturers to trace the last minutes of battery activity before a thermal event, offering critical information about the incident. 

4. Use postmarket surveillance to granularly scope EV recall activities 

Data visibility across the battery and powertrain performance of EVs can also help manufacturers scope recalls on a more granular level, including isolating the correct production lot and tracing the origin of defective components. 

Deploying a software information architecture system that fully leverages EV data streams can enable vehicle-by-vehicle analysis during a warranty or recall investigation and avoid the need to cast a wide net over a vehicle's lot or model population. By assessing an individual vehicle's performance for degradation or failure markers, the number of affected vehicles in a recall can be minimized to only those presenting the issue versus all vehicles from a particular group. In turn, this can substantially reduce the recall cost for EV manufacturers and improve customer outcomes.

The technical challenges of leveraging data from fleets of EV batteries will only grow more complex as more information becomes accessible

Looking to the future of real-time EV battery monitoring

The technical challenges of leveraging data from fleets of EV batteries will only grow more complex as more information becomes accessible — and data becomes a more fundamental driver of insights and actionable strategies for EV manufacturers.

Looking to the future, OEMs are now working on battery and powertrain designs that incorporate wireless battery management system technologies, such as shedding vehicle weight by swapping the physical wiring connecting various control units for wireless communication. Future EV battery pack monitoring advancements may also include more localized pressure sensing to detect swelling at the cell level and using gas sensors to identify specific known gasses that may be generated during a cell outgassing event. As these new innovations, and others, are added to battery packs, the demand to comprehensively analyze the information available will only become more rigorous.

To prepare for a fast-changing future and for potential reliability or failure scenarios, EV manufacturers can ready themselves by working to develop a nuanced understanding of the growing number of sensors across the drivetrain, boosting the data capture of the cars' connectivity features, and achieving more granular insights into individual cell health and overall battery pack health at the fleet level. When implemented appropriately, the insights derived from these efforts can help improve battery performance and lifespan, potentially reduce recall-related costs, and speed root-cause analysis of failures.