Chalmers researchers model reconfigurable EV battery packs that bypass weak cells
Chalmers University researchers modeled reconfigurable battery packs that can bypass weak cells to extend EV battery life and reduce cost, while US EV sales data shows Tesla Model Y and Model 3 leading Q3 2026 rankings with Hyundai IONIQ 5, Toyota bZ, and Chevrolet Equinox EV following.
Researchers at Chalmers University of Technology in Sweden have assessed how much reconfigurable battery packs could extend EV battery life and reduce lifetime cost. The study was carried out with PHINIA and Scania.
Chalmers researchers model reconfigurable EV battery packs that bypass weak cells
Battery packs in EVs consist of many interconnected cells that do not age in the same way. In a conventional pack, the weakest cell can therefore set the limit for the entire pack.
Albert Škegro, a doctoral student at Chalmers and the study’s first author, explains the problem by picturing the cells connected by a rope while they all try to move forward. “Since they are bound to each other, everyone has to keep the same pace as the slowest cell and stop when that cell stops,” said Škegro. “With the solution in our study, the battery can instead bypass the cell that is causing problems and continue forward.”
In a reconfigurable pack, switches and control systems can change the connections between the cells. The researchers say that in their models, controlling each cell separately could extend battery life by over 20% in some high-voltage vehicles, such as electric trucks and long-range cars. In practice, groups of cells are more likely to be controlled together, so that figure is a theoretical upper limit.
In one example, the researchers modeled a typical 80 kWh battery in a car driven 12,000 km per year and assumed a conventional pack would be replaced after 10 years. In the model, the reconfigurable pack reached that replacement point after about 11 years, roughly 14 months later. It also had a higher residual value because it had degraded less.
The technology is not yet available in series-produced vehicles but has been tested in research and industrial prototypes. Reconfigurable packs require additional electronics, which raise their upfront cost.
The results show that the architecture can already be cost-effective under a wide range of real-world usage conditions, said Changfu Zou, Professor at the Department of Electrical Engineering at Chalmers. Based on a component-level analysis using automotive-grade hardware, the additional hardware would increase the total pack cost by approximately nine percent.
These are the top 10 best-selling EVs in the US through Q3
The US electric vehicle market delivered its strongest performance in a year in the third quarter. Here are the top 10 most popular so far this year.
Through Q3, Tesla remains the dominant leader, with the Tesla Model Y and Model 3 holding the No. 1 and No. 2 spots.
Hyundai’s IONIQ 5 remained America’s most popular EV not named Tesla, ranking third with 31,112 units sold through September.
The Toyota bZ ranked fourth after sales doubled to nearly 25,000 units. Toyota’s electric SUV continues winning over buyers after the updated 2026 model went on sale late last year.
In fifth was the Chevrolet Equinox EV, despite sales dropping 65% from last year with 18,154 units sold.
The Hyundai IONIQ 5, Toyota bZ, and Chevrolet Equinox EV are among the most affordable electric vehicles, starting at around $35,000.
The Rivian R1S ranked sixth, followed by the Ford Mustang Mach-E, Rivian EDV, Honda Prologue, and Kia EV9.
With several new models now on sale, such as the Kia EV3 and Rivian R2, the list could look very different by year’s end.
Looking ahead, the next stage of growth will come from great products, competitive pricing, and automakers that continue to give consumers compelling reasons to make the switch, Valdez Streaty said, adding, With gas prices well above $4 a gallon, electric vehicles look better than ever.
