On April 22, 2026, the European Commission officially brought into force the Detailed Rules for the Implementation of the New Battery Regulation (Annex VII-A), making it clear that starting from October 2026, all voltage, temperature, and current sensor modules used in power battery BMS systems entering the EU market must integrate a real-time SOC (state of charge) calibration communication interface compliant with the UN/ECE R100.03 standard. This requirement is directly related to the compliance capabilities of Chinese BMS sensor manufacturers, module integrators, and new energy battery exporters, and in particular constitutes a substantive technical market access threshold for companies supplying European vehicle manufacturers and energy storage projects.

Event Overview

On April 22, 2026, the European Commission issued and formally implemented the Detailed Rules for the Implementation of the New Battery Regulation (Annex VII-A). According to these detailed rules, starting from October 1, 2026, all power battery systems placed on the EU market must ensure that the voltage, temperature, and current sensor modules used in their battery management systems (BMS) are equipped with a standardized communication interface that can be accessed in real time by external devices to retrieve and verify SOC values, and this interface must meet the mandatory technical requirements of UN/ECE R100.03 regarding functional safety and data interaction for onboard battery systems. Leading battery companies such as CATL and BYD have already issued technical response letters to domestic sensor suppliers; manufacturers of combined temperature-pressure sensor modules such as Xi'an Shenghongchuang have also confirmed that their existing export solutions need to be adjusted accordingly.

Which Market Segments Will Be Affected

Direct Trading Enterprises

Trading companies engaged in exporting BMS sensor modules to Europe will face stricter product market access reviews. The impact is mainly reflected in the following: existing sensor modules without an SOC calibration interface will be unable to pass EU Type Approval, resulting in customs clearance obstacles or order cancellations; at the same time, customer factory audits and technical documentation review cycles may be extended, affecting delivery schedules.

Processing and Manufacturing Enterprises

Manufacturing enterprises focused on the development and production of BMS sensor hardware (such as manufacturers of integrated multi-parameter temperature/voltage/current modules) will need to redefine their product architecture. The impact is mainly reflected in the following: at the hardware level, communication pins compliant with the R100.03 protocol and underlying firmware support must be added; at the software level, real-time reading, signing, and timestamp synchronization of SOC calibration data must be implemented; in the testing stage, R100.03 consistency verification procedures must be added.

Supply Chain Service Enterprises

Service organizations that provide battery manufacturers with sensor selection, testing and certification guidance, and preparation of CE marking technical documentation will shift their focus toward R100.03 interface compliance assessment. The impact is mainly reflected in the following: existing standard service capabilities aimed at EN ISO 12405 or IEC 62660 series must be extended to the UN/ECE regulatory framework; third-party laboratories must be coordinated to carry out R100.03 communication protocol stack verification, with technical service cycles and costs rising accordingly.

Channel Distribution Enterprises

Distributors acting as agents for international-brand sensors or distributing domestic modules to overseas integrators will face concentrated inquiries from downstream customers on “whether R100.03 SOC calibration interface is supported”. The impact is mainly reflected in the following: product catalogs and specification sheets need urgent updates to technical parameter items; some inventory models that did not anticipate this interface face the risk of slow-moving stock; upstream manufacturers must be coordinated to provide interface compatibility statements and test reports to support sales claims.

What Key Points Should Relevant Enterprises or Practitioners Pay Attention To, and How Should They Respond at Present

Pay Attention to the Subsequent Official EU Release of the R100.03 Interface Implementation Guidelines and Test Case Sets

Although UN/ECE R100.03 has already been issued, its specific implementation methods at the sensor level (such as physical layer protocol selection, data frame format, and security authentication mechanism) still need to be further refined by EU type approval bodies (e.g., TÜV Rheinland, SGS). Enterprises should continue to track updates from the GRRF working group under UNECE WP.29 to avoid blindly developing based only on general CAN FD or UART communication solutions.

Differentiate Between “Interface Presence” and “Functional Compliance”, and Prioritize Verification of the Traceability and Tamper Resistance of SOC Calibration Data

From an industry perspective, what deserves more attention at present is whether the interface truly supports calibration requests initiated by external devices, returns SOC values with digital signatures and corresponding timestamps, rather than merely reserving communication pins. Enterprises should organize internal testing in advance to compare the response consistency and error range of different SOC algorithms (such as coulomb counting + open circuit voltage combined estimation) under calibration triggering.

Review Existing Export Product Lines, Identify High-Risk Models, and Launch Technical Retrofit Plans

It is recommended to cross-screen affected products based on three dimensions: “whether EU battery type approval has been obtained”, “whether supporting designated BMS platforms of customers such as CATL/BYD”, and “whether customized communication protocols are used”. For models that still have delivery plans before October 2026, it is advisable to immediately launch parallel hardware PCB redesign and firmware upgrade work, while simultaneously preparing updated materials for the Declaration of Conformity (DoC) signed by the EU authorized representative.

Strengthen the Tripartite Coordination and Communication Mechanism with Battery Manufacturers and Certification Bodies

From the analysis, the issuance of letters by leading enterprises such as CATL and BYD itself indicates that they are simultaneously advancing adaptation verification of their own BMS systems for the R100.03 interface. Sensor suppliers should proactively connect to their testing environments, obtain sample calibration command sets and response expectations from the actual BMS master control side, and avoid protocol incompatibility issues arising after unilateral development.

Editorial Viewpoint / Industry Observation

From observation, the implementation of these detailed rules is not an isolated technical upgrade, but a key step in the EU's forward shift of battery full-lifecycle data sovereignty management to the sensing layer. It is more like a clear policy signal——in the future, the EU market's requirements for the underlying capabilities of battery systems to be “verifiable, auditable, and intervenable” will extend from battery cell material traceability to BMS sensing nodes. What the industry needs to continue paying attention to is: whether the R100.03 interface will become the data input source for subsequent regulatory scenarios such as carbon footprint declarations and reuse grading; and whether this interface may be incorporated into the Battery Passport data collection framework scheduled to be implemented in 2027.

Conclusion
This event marks that EU battery regulation has moved from the stage of macro-level institutional design into the stage of micro-level technical execution. For the domestic BMS sensor industry chain, this is not only a task of adding a single interface, but also a systematic stress test of product definition logic, testing and verification systems, and international regulatory response mechanisms. At present, it is more appropriate to understand it as: a compliance critical point with a clear timeline, a defined technical path, and substantive actions already triggered by leading customers, rather than a distant uncertain risk.

Information Source Notes
Main sources: official announcement on the European Commission website (Regulation (EU) 2023/1542 Annex VII-A, version effective on April 22, 2026); technical response letters sent by CATL and BYD to suppliers (summary information available through public channels); public statement by Xi'an Shenghongchuang regarding adjustments to export solutions for combined temperature-pressure sensor modules.
Items pending continued observation: the specific testing methods and certification acceptance list for UN/ECE R100.03 at the sensor level are expected to be released successively by technical service institutions designated by EU member states in the third quarter of 2026.