All batteries for light mobility, industrial applications and electric vehicles within the European Union (EU) must have a battery passport from 2027. This passport must contain detailed information on the battery's condition, performance and origin. With the Secure Battery Passport Demonstrator (SeBaPaD), TNO and Dutch chip manufacturer NXP have developed a solution that ensures this data is reliable, secure and interoperable.
The battery passport is a digital system that collects, stores and shares detailed information about a battery's life cycle, performance, origin and sustainability. It is a mandatory part of the EU Battery Regulation, which comes into force from 2027 for batteries used in light mobility (such as e-bikes), industrial applications and electric vehicles.
More transparency and insight
Among other things, the passport should provide transparency on the origin of raw materials and production processes. It should also encourage circularity by providing information on the recycling possibilities and residual value of batteries. The condition, performance and safety of batteries should be visible through the passport throughout their life cycle. Finally, the battery passport should deter fraud in reuse and recycling.
TNO has been focusing on battery passport development for some time. In 2024, for instance, it published a white paper as part of the Green Transport Delta - Electrification (GTD-E) project, which laid a technical foundation for the passports. TNO and NXP's SeBaPaD project builds on this. For the project, NXP provided the hardware for the Battery Management System (BMS), including secure chipsets. TNO developed the SoX battery algorithms and integrated them with a commercial NMC battery module.
In addition, an end-user group with industrial partners is involved in the project. They contribute to the practical relevance of the project.
SoX Toolchain
One of the core requirements of the battery passport is to report State-of-X (SoX) values, which describe the condition and performance of a battery. SoX includes metrics such as charge capacity, health and efficiency, as well as new indicators such as round-trip efficiency that are often missing from existing BMS systems.
TNO developed the SoX Toolchain, a framework that combines existing operational data with dynamic data for the battery passport. A key challenge is that many existing SoX algorithms become less reliable as a battery ages. The SoX Toolchain evaluates the performance of SoX estimates over the entire battery life, allowing users to reliably monitor condition and performance on an ongoing basis.
Extremely high security level
To test the SoX algorithms, the software was integrated with NXP's BMS hardware. This hardware contains security ICs (chips) that protect the sensitive data and prevent manipulation. "The chipsets have an extremely high security level. It is the same type used for credit cards and passports," explains Marc Manninger of NXP. This is essential because battery manufacturers are legally liable for the reliability of the data.
The BMS consists of several layers of software. At the lowest level, raw signals such as cell voltage, current and temperature are measured. The core software ensures secure operation, while the application layer provides more advanced functions such as SoX algorithms. The framework builds on validated and protected data, enabling reliable calculation of both operational measured values and dynamic passport data.
The battery passport has been tested under a variety of conditions in TNO laboratory facilities, including climate chambers. "This allows us to test batteries at different temperatures and humidity levels and verify that their behaviour remains within expected limits," explains Feye Hoekstra, Battery Scientist at TNO. This is crucial for passport validation, especially at higher voltage levels common in industrial applications.
Scaling up
With the completion of the first SeBaPaD project, TNO and NXP are now focusing on scale-up. One focus area is testing the battery passport with LFP batteries, which are more challenging for SoX calculations due to their flat voltage curve. In addition, SeBaPaD 2 is scaling up from a 50V battery module to a 500V battery pack, aiming to get closer to industrial and mobility applications.
