China’s GB 38031-2020, implemented at the start of 2021, set the level for the global industry on EV thermal runaway safety. It was the first mandated standard with a 5-minute warning for occupants to escape the vehicle.
In April 2025, it was announced that China’s GB 38031-2025 would be mandated for new vehicles by July 2026. This 2025 update goes well beyond the previous one, requiring no fire or explosion for 2 hours after the initial event.
Whilst China continues to outpace the world in EV sales, with EVs accounting for 49% of new car sales in 2024, according to IDTechEx research, it is also ahead of the rest of the world with safety standards.
China’s New Requirements
China’s 2025 version of the 38031 standard includes a few key changes. The most surprising is the requirement that no fire or explosion occur for 2 hours after thermal runaway initiation in a single cell. The warning to the vehicle occupants is still present, and no visible smoke should enter the passenger compartment within 5 minutes of the event.
The standard also adds internal heating, external heating, and puncturing to the list of testing trigger mechanisms. If thermal runaway does not occur with one of these test methods, the other methods should be tested.
China’s EV market has become increasingly dominated by LFP chemistry, which makes adhering to this challenge easier than with the higher energy density NMC chemistries. But it is still not straightforward, as no energy storage system is 100% inherently safe.
What is clear is that China’s standards regarding thermal runaway in EVs are moving much quicker than those of other regions, which are still going through drafts, revisions, and updates with no mandated standards in place.
What’s happening in Europe?
Europe is looking to the UN ECE R100 standard and its changes. The R100-05 version will be implemented for new vehicle types in September 2027 and for all new vehicle types by September 2029.
It is significantly behind China’s 2026 implementation and has requirements much more similar to China’s 2020 standard! A 5-minute warning to vehicle occupants after a thermal event, during which no hazardous situation can occur for the occupants (fire, smoke, or explosion).
The latest updates look to have more specificity in the testing mechanisms, rather than the final safety outcome.
Is the US Even Further Behind?
While the US also examines the UN ECE regulations, NHTSA is the key body for mandating safety. Its latest revision of FMVSS 305a closely follows the UN ECE regulation, but has adopted a less stringent safety standard. Here, there is no need to detect single-cell thermal runaway; it is wholly based on the temperature within the pack.
Whilst GTR20 requires a 5-minute warning before a single cell enters thermal runaway and threatens the occupants, NHTSA argues that detecting a single cell would be “unduly design restrictive” and irrelevant in all conditions.
Rather than a warning triggered by a single cell failure, NHTSA proposes a warning system triggered by temperatures inside the battery system significantly exceeding the maximum operating temperature.
To test this system, the battery should be opened, and a heater that reaches 600°C in 30 seconds should be attached to the cell/cells so that at least a single cell enters thermal runaway. The warning must occur within 3 minutes of the heater initiation.
How Do Automakers Adapt?
When China announced the 2020 standard, automakers adapted existing battery platforms to meet the new standard. This time, automakers have been considering fire safety at a much earlier stage in the design process and have been trying to exceed the 5-minute warning.
However, China’s new 2-hour need is a massive curveball. Preventing thermal runaway between cells is undoubtedly possible, and several material options exist. However, as always, there is a trade-off between performance and price for each battery design. This all comes when reducing battery costs, which is paramount for future EV adoption.
Safer vehicles are undoubtedly good, but also a significant challenge for automakers and battery designers. Automakers tend to want a design that can be used globally without too many alterations for a specific market.
IDTechEx’s report, “Fire Protection Materials for EV Batteries 2025-2035: Markets, Trends, and Forecasts,” predicts that the market for these materials will experience a 15% CAGR with the growing EV market and increased focus on fire safety.
Fire protection will continue to be considered early in the design process, which presents enormous opportunities for materials suppliers who can help automakers meet these new requirements.