Guest blog: Navigating new regulations for EV Type Approval

The next update to UNECE Regulation 100, Revision 3, has significant implications for automotive manufacturers and the tiered supply chain. Extra measures will need to be undertaken when both designing and validating battery packs in EVs, with additional testing requirements having the potential to increase type approval costs and substantially impact timelines.

Yet, while the new requirements have been outlined, engineering teams face further complications as these updates are open to interpretation: specific test methodologies to provide compliance assurance have not been mandated. With battery technology still in its relative infancy compared to the internal combustion engine, it’s a challenging situation for OEMs to navigate, and one that could prove all the more costly if not addressed well ahead of its Q3 2023 implementation. 

New Type Approval requirements

UNECE Regulation 100.03 has two parts, the first of which refers to safety of the electric powertrain of road vehicles, including additional requirements such as the battery pack’s resistance against water ingress when washing and wading through standing water. Test methods for this are defined and therefore straightforward to implement.

Part two covers safety requirements with respect to the Rechargeable Electrical Energy Storage System (REESS). This includes proof of design as well as component testing prior to installation, spanning destructive and non-destructive testing, low-temperature protection, warnings in the event of failure of vehicle controls and five-minute warnings in the case of a thermal event. The extent of the requirements means some manufacturers may need to review the design of their battery packs.

Test methodology

When it comes to testing methodology, for thermal propagation, for example, it’s stated that ‘[…] a risk reduction analysis using appropriate industry standard methodology’ (6.15.2.1) must take place: potential methods are listed but none mandated.

There’s been much debate regarding the most effective methods for inducing thermal runaway and thermal propagation during validation – nail penetration, overcharging or overheating – with countries and OEMs taking different stances and an industry consensus yet to be reached. Additionally, there are instances where the regulation references ‘data obtained from either testing or simulation’ but no suitable methods are outlined. While future regulation updates may provide more concrete details, this is not confirmed or available in the short term to aid engineering teams in updating their validation and testing processes.

The result is that OEMs could take differing interpretations of these standards. Some manufacturers may look at the most cost-effective interpretation or perhaps the quickest route to meet the impending regulations, potentially exposing them to further engineering challenges down the line. Alternatively, it could be interpreted from an integrity point of view while making the battery pack as integrally safe as possible. Against the regulation, neither is right nor wrong, but HORIBA MIRA’s interpretation is to make batteries, vehicles and therefore roads as safe as possible.

A safe interpretation

With safety prioritised and complemented by decades of engineering experience and consultation on associated standards and regulations, HORIBA MIRA has developed a comprehensive methodology for meeting UNECE Regulation 100.03. It also draws on testing and validation guidance from two existing standards: ISO 6469-1 and GTR20. The first is a newly released amendment to an existing standard at the forefront of thermal propagation standards, while the latter is a global electrical safety regulation with close alignment to R100.

With this in mind, HORIBA MIRA is able to support manufacturers, helping them navigate the process and providing guidance on the most effective, efficient and safe methodologies to prove compliance. For example, for thermal propagation, HORIBA MIRA has found overheating to be an effective and reliable test method; whereby one cell is removed from the pack and replaced with a heater element that causes a thermal event that spreads to other cells. It allows testing to start from a specific point in the pack and is repeatable and reliable. Both nail penetration and overcharge testing have variables that can impact the repeatability of testing of the pack.

Additionally, amongst other testing technologies, HORIBA MIRA’s heat map equipment can further support by digitally predicting how a thermal event will take place, which route it would take through the battery pack and the point at which flames breach the vehicle cabin.

Minimising impact for the future

The new regulations require significant consideration at all stages, starting from the design of the pack. Some OEMs may already be doing this work pre-emptively or from an ethical standpoint, but thermal runaway and the new thermal event warning signals will be new to some. These regulatory updates will have such a significant impact on battery pack design that re-work, if not full re-design of battery packs, may be necessary. This can be costly in terms of developing and validating the updates, not to mention the capability and expertise necessary to make it work. At all stages of the V-cycle, HORIBA MIRA’s engineering team can offer guidance and support in testing and validation to meet UNECE Regulation 100.03 in advance of its implementation.

HORIBA MIRA Electrical Certification Engineer Nicholas Bates