One of the main obstacles to EV adoption is battery lifespan. Although improved manufacturing has extended battery life beyond original estimates of eight to ten years, replacement costs remain a concern. Researchers in Sweden have developed an approach that could extend battery life by over a year while reducing ownership costs.
Battery lifespan is often determined by the weakest cells in the pack. Manufacturing variations and uneven ageing cause some cells to deteriorate faster than others, potentially requiring replacement of a battery containing many healthy cells. Researchers at Chalmers University of Technology and industry partners have developed a reconfigurable system that bypasses deteriorating cells, potentially extending battery lifespan by more than 20%.
This theoretical maximum assumes individual control of every cell. Manufacturers could instead control groups of cells, reducing electronic complexity and costs while sacrificing some benefits.
To assess the financial impact, researchers modelled an EV with an 80 kWh battery, travelling 12,000 kilometres annually, with an expected lifespan of 18.8 years. Their calculations suggest the technology could delay battery replacement by approximately 14 months while increasing residual value through reduced degradation. Actual results depend on battery capacity, mileage and operating conditions.
The advantages become more significant in high-voltage applications with numerous cells connected in series. As cell numbers increase, so does the likelihood of uneven deterioration. In conventional batteries, one weak cell can limit overall performance.
Automotive manufacturers have investigated reconfigurable batteries for several years, including applications in stationary energy storage. Volvo Cars explored the concept through its SmartCell project, while another major manufacturer has begun road testing a passenger-car prototype. However, no mass-produced passenger vehicle currently incorporates the specific architecture examined in this research.
Additional electronic components and sophisticated controls increase initial battery costs. Researchers estimate that the required equipment would raise total pack costs by approximately 9%. Their analysis identifies a threshold of around 12%, beyond which the technology becomes less likely to provide an economic advantage over the vehicle's lifetime.
Longer battery life could also deliver environmental benefits by reducing replacement frequency and improving opportunities for reuse after a vehicle reaches the end of its service life. Extending the useful life of existing cells would also help conserve valuable battery materials and reduce demand for new battery production.
Although further testing is required to validate performance and economic benefits under commercial operating conditions, the findings suggest reconfigurable batteries could offer manufacturers a practical route towards longer-lasting EVs. By allowing healthy cells to remain operational despite deterioration elsewhere in the pack, the technology could reduce ownership costs, improve battery utilisation and support more sustainable electric transportation.
