Significant Amendments to UN ECE Regulation No. 100

At the 195th session of the United Nations Economic Commission for Europe (UN ECE) World Forum for the Harmonisation of Vehicle Regulations (WP.29), the 05 Series of Amendments to UN ECE Regulation No. 100 was adopted. This revision is crucial, as it aims to define new specific standards for vehicles equipped with electric powertrains.

The most significant element of these updates involves the introduction of requirements designed to counteract “thermal propagation” within Rechargeable Electrical Energy Storage Systems (REESS). Simply put, we’re talking about the dreaded scenario where a “thermal runaway”, an uncontrolled overheating, occurs in one battery cell and, like a domino effect, spreads to adjacent cells.

To tackle this challenge, the 05 Series of Amendments has developed four alternative physical testing methodologies. These procedures allow for intentionally inducing a “thermal runaway” in a single cell, in order to evaluate its “thermal propagation” within the REESS. Versatility is a key point: these tests can be conducted at different scales, adapting to specific needs. One can opt for evaluation at the complete vehicle level, observing the interaction between the battery pack and the entire vehicle system; or at the complete REESS level, for an in-depth analysis of the battery pack in its entirety; finally, it’s possible to go into detail by testing at the REESS sub-system level, focusing on smaller modules or sections.

The entry into force of these amendments will follow a precise timeline. Compliance will become a mandatory requirement for new type approvals starting September 1, 2027. This means that, from that date, every new electric vehicle model introduced to the market will need to comply with these provisions. Subsequently, the rule will extend: compliance will be mandatory for all type approvals, including existing ones, from September 1, 2029. This gradual approach ensures that the entire electric vehicle fleet progressively adheres to higher safety standards.