Can 300 Seconds Save Lives in New Energy Vehicles?

This article explores the safety challenges associated with fires caused by collisions in new energy vehicles. It analyzes the limitations of the current national standard that allows for a five-minute warning before thermal runaway occurs, highlighting the difficulties in escape and rescue during high-speed impact scenarios. A new battery safety standard is set to be implemented in 2026, mandating that batteries must not catch fire or explode. Experts compare the fire risks of electric vehicles (EVs) with those of traditional fuel vehicles, emphasizing the importance of technological upgrades and supply chain quality on safety. Additionally, it discusses the challenges of extinguishing lithium battery fires and rescue strategies.

• New National Standards: Stricter battery safety standards will be implemented in 2026, requiring batteries to not catch fire or explode after thermal diffusion.
• Escape Challenges: In the event of multiple cells losing control due to high-speed collisions, the five-minute warning may be insufficient; actual rescue efficiency must be considered.
• Controversy Over Fire Probability: Experts state that the spontaneous combustion rate of electric vehicles is lower than that of fuel vehicles, but the flammable nature of electrolytes after a collision increases risks.
• Technological Upgrades: 78% of companies possess thermal runaway suppression technology, and improvements in vehicle design enhance battery protection.
• Rescue Difficulties: The high rate of reignition in lithium battery fires necessitates specialized equipment for continued cooling; standard fire extinguishers are only effective in the early stages.
• Supply Chain Concerns: Some manufacturers prioritize low-cost, borderline-compliant batteries, which can compromise product stability due to potential technological copying.

When a new energy vehicle experiences a high-speed collision, the battery can be breached, ideally providing a five-minute warning before a fire ignites, as mandated by national standards. However, the effectiveness of this “golden five minutes” in saving lives faces numerous challenges. For instance, on March 29, a collision involving a Xiaomi SU7 on the G0321 highway in Chizhou, Anhui, resulted in a fire and three fatalities. Following the incident, Xiaomi stated that the vehicle was in NOA intelligent driving mode prior to the collision, and the driver had taken control, attempting to steer the vehicle away, but a crash occurred. Later, Xiaomi clarified that the fire was not due to spontaneous combustion but rather severe damage to the vehicle’s system after a violent impact with a concrete barrier.

As electric vehicles now account for half of all car sales in China, the questions surrounding their fire safety and escape strategies are increasingly urgent. On February 28, the “Defect Analysis Method for Electric Vehicle Fires” was officially implemented, aiming to standardize the investigation and analysis of electric vehicle fire incidents. Current regulations primarily rely on static tests and fail to cover high-speed collision scenarios. The new standard emphasizes the need for data from real accidents to refine analysis methods for better recall management and safety oversight.

The existing standards require that within five minutes of thermal diffusion, the battery must issue a warning signal before posing danger to the passenger compartment. However, the updated “Safety Requirements for Power Storage Batteries in Electric Vehicles” (referred to as “Safety Requirements”) will enforce stricter regulations stating that batteries must not ignite or explode after thermal diffusion. The draft of this new regulation is expected to be released in the first half of 2025 and implemented in July 2026, replacing the previous standards from January 2021.

Are Five Minutes Enough for Survival?

A new energy vehicle typically contains over a hundred battery cells. If one cell undergoes thermal runaway, it can trigger a domino effect, leading to a fire in the entire battery pack. According to the current “Safety Requirements,” the battery pack must not explode or catch fire within 30 minutes of an accident, nor should any electrolyte leak into the passenger compartment. However, specific testing conditions are mandated, with minimum speeds of 50 km/h for frontal impact tests and 32 km/h for side-impact tests. Although the standards require a warning signal within five minutes of thermal diffusion, they do not explicitly mandate that the battery must not ignite or explode.

It is important to note that there is no countdown timer during an accident to indicate how long until the five minutes are up. “The five-minute standard is based on laboratory conditions, but thermal propagation can vary significantly in real-life scenarios,” a fire safety expert noted. The current “Safety Requirements” permit battery fires under certain conditions, provided that users have sufficient time to evacuate. The five-minute evacuation window is derived from simulations and tests, and has been widely adopted internationally. Liu Guibin, Secretary-General of the Technical Committee of National Automotive Standardization, explained that the “national standard certification” sets only the minimum threshold for safety, and laboratory conditions do not guarantee safety in all real-world situations.

Some manufacturers opt for cheaper, thinner materials to meet standard requirements, which can compromise safety when faced with complex issues. Moreover, some companies have begun to develop their own technologies, creating competition among suppliers that may lead to instability in product quality. As outlined by battery researcher Zhu Yulong, extreme conditions, such as high-speed collisions with sharp objects, can lead to catastrophic breaches of the battery pack, exceeding the safety limits set by these standards.

Is It Easier for Electric Vehicles to Catch Fire?

In 2024, the Chinese Fire Department reported over ten incidents of new energy vehicle fires. According to an analysis by China Securities Journal, 2.32 million vehicles were recalled due to fire risks, with 380,700 being new energy vehicles, of which 283,000 involved battery issues. Electrolytes are highly volatile and flammable, meaning that if a battery is damaged and the electrolyte leaks, it can ignite upon contact with high temperatures or sparks. Collisions may also cause short circuits, releasing significant heat in a short period. Exceeding temperature thresholds can lead to thermal runaway and subsequent fires. During a collision, the battery pack may become compressed or punctured, rupturing the separator between cathodes and anodes, leading to a short circuit. High-voltage lines (typically 300V to 800V) can also spark or create localized heat if damaged, igniting surrounding materials.

Investigation reports of electric vehicle fires after collisions reveal cases where the battery pack remained intact despite severe vehicle damage. Some companies have suggested that fires are ignited by high-temperature components or sparks due to short circuits in the front compartment.

So, are electric vehicles more prone to catching fire? In March 2024, Ouyang Minggao, an academician of the Chinese Academy of Sciences and a professor at Tsinghua University, stated that the self-combustion rate of new energy vehicles is lower than that of fuel vehicles. He cited data from relevant national agencies, concluding that the fire rate for new energy vehicles was lower in the first quarter of 2023 compared to fuel vehicles. The causes of battery fires can be classified into external and internal factors. External causes include overcharging, excessive charging power, and significant impacts, while internal factors stem from inconsistent production quality leading to internal short circuits.

This conclusion has sparked debate, as factors such as vehicle inventory, usage state, service life, and causes of fires were not considered. While the statistics refer to spontaneous combustion rather than collision-related fires, the general perception in the industry is that electric vehicle safety is improving. According to Chinese Academy of Engineering academician Sun Fengchun, the probability of new energy vehicle fires fell from 0.049% in 2019 to 0.026% in 2020, while traditional fuel vehicles have a fire incident rate between 0.1% and 0.2%. This improvement is attributed to technological advancements in battery production and a trend of market consolidation, with smaller companies exiting the market. Additionally, vehicle manufacturers are increasingly focused on enhancing safety through updated materials and manufacturing technologies.

Liu Guibin noted that, as of February 2024, 78% of the 36 surveyed vehicle and battery companies possess technologies that prevent battery fires and explosions, ensuring that even if a single cell experiences thermal runaway, it will not lead to a fire or explosion in the battery pack.

How to Respond After an Electric Vehicle Fire?

Rescuing individuals from electric vehicle fires has been a persistent challenge. “Electric vehicles of the same size tend to have higher temperatures when on fire, and lithium battery fires are particularly difficult to extinguish,” a fire rescue expert indicated. It is recommended to use dry powder fire extinguishers first; if necessary, water hoses can be employed to cool the battery pack to prevent explosive re-ignition. However, fires can reignite and emit toxic gases, posing additional challenges.

The best approach is to utilize specialized firefighting equipment, although these tools are costly and have stringent usage requirements, making them more common in high-risk areas. “An electric vehicle fire does not mean there is no chance of rescue,” the expert added. Using a dry powder extinguisher in the early stages can help control smoldering fires in lithium batteries, providing precious time for escape and subsequent rescue efforts. At a domestic airport, all buses and engineering vehicles utilizing batteries prominently display the type of battery used and the required specialized firefighting equipment.

(Disclaimer: This article aims to clarify the safety challenges currently faced by the automotive industry and does not address any specific incident. All investigations into incidents are subject to official conclusions.)