Revolutionizing Electric Vehicle Batteries: Smart Sensors Enhance Safety and Longevity

Turning Cells into Sensors: How E-Car Batteries Get Smarter and Safer
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A new battery management system promises to enhance the safety, sustainability, and lifespan of electric car batteries. By transforming battery cells into sensors that can detect hidden faults and temperature fluctuations, this innovative “electronic brain” helps prevent failures and improve performance. “We integrated it into a car and proved it works,” say the developers. “Now the challenge for the industry is to make it affordable.”

If you attended “The Battery Show Europe” in Stuttgart, Germany, recently, you might have seen a small demo car featuring a battery installed under the seat with 14 cells connected in series. At first glance, it may not have seemed remarkable, especially with this year’s theme focusing on “Driving sustainability, resilience, and innovation in Europe’s battery industry.” However, a closer look revealed a display showcasing various metrics. The true innovation of this prototype lies in the data it presents, which includes not only the battery’s charge level but also the health status and temperature of each individual cell—promising enhanced safety, longevity, and sustainability.

This is achieved through a “battery management system” (BMS) known as zBMS. The “z” in its name indicates its focus on impedance. “For the industry and the scientific community, Z stands for the impedance,” explains Andreas Hutter, Leader of the Battery Systems group at the Swiss technology transfer center CSEM. Hutter likens impedance to the resistance faced by water flowing through a pipe: “The water represents electric current, while the pressure pushing it represents voltage. If the pipe’s diameter decreases, resistance increases, limiting current flow. In electrical terms, increased impedance reduces current capacity.”

In lithium-ion batteries, current is generated by electrons moving between the anode (negative electrode) and the cathode (positive electrode), with ions shifting back and forth to charge and discharge the battery. “It’s like a race full of hurdles, where obstacles might trap or mislead some electrons,” Hutter notes. Since these obstacles diminish battery capacity and performance, the first step toward improvement is identifying them.

Unlike current practices, which often rely on invasive methods, this system measures impedance at various frequencies using a non-invasive technique called “impedance spectroscopy.” This method allows developers to identify issues without opening the battery. Md Sazzad Hosen, a part-time professor and senior battery researcher at the Free University of Brussels (VUB), leads the European consortium NEMO, which is behind the zBMS development. “With electrochemical impedance spectroscopy (EIS), you can gain precise insights into battery performance and lifespan, as well as predict overheating or safety risks,” he explains.

EIS allows for impedance measurement without requiring additional sensors. “This is advantageous because integrating a sensor inside a cell is complex,” remarks Jan Philipp Schmidt, a professor of Systems Engineering of Electrical Energy Storage Systems at the University of Bayreuth. “Moreover, while sensors typically measure temperature at a single point, impedance spectroscopy can determine the temperature across the entire battery.”

One significant advantage of this method is its ability to maintain performance even in the presence of internal failures. Since batteries consist of numerous interconnected cells, damage to some cells can impact the entire system. “In a battery module with 15 cells, if two cells are damaged, impedance measurements and the cell management system enable us to bypass those failures and rely on the remaining 13,” Hosen clarifies. “This ensures safe and reliable operation.”

Experts refer to this process as “balancing,” which serves two purposes: prolonging the system’s lifespan by maintaining uniform cell health and using the hardware to identify and avoid failing cells. Schmidt emphasizes the need for further research, as several barriers still limit the widespread adoption of impedance-based battery management systems. “The technology is advancing rapidly, which is promising,” he states. “However, while traditional systems rely on a sensor designed for multiple applications, impedance spectroscopy turns the cell itself into the sensor. Consequently, with every new generation of higher-performing cells, all previous data must be revalidated.”

Despite these challenges, significant progress has already been made. Although impedance spectroscopy is a well-established technique, its application for gathering diagnostic data in electric vehicle batteries is relatively new. “It started being used around 2011 or 2012 to replace sensors and measure cell temperatures, inspiring researchers to extend this functionality beyond the laboratory,” notes Schmidt.

The NEMO project aims to contribute to the future of battery management systems by miniaturizing the system and integrating it into cars, demonstrating its operational viability. “This technology could improve safety and extend battery life by 20%, while also simplifying validation for second-life applications,” Hutter states. However, implementing this system in car batteries would increase the final product’s cost from approximately €10 to €13, which represents an additional nearly 30% increase—currently a significant barrier, he adds. “Thus, the industry’s challenge is to make it affordable.”

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**Citation:** Turning cells into sensors: how e-car batteries get smarter and safer (2025, June 13) retrieved 14 June 2025 from [Science X](https://sciencex.com/wire-news/511259570/turning-cells-into-sensors-how-e-car-batteries-get-smarter-and-s.html).

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