Recently, a Xiaomi SU7 operating under NOA smart driving assistance encountered a tragic incident while driving on the Chiqi section of the De Shang Expressway. Due to road construction ahead, the vehicle detected an obstacle and issued a warning while automatically reducing speed. However, the driver took over control, and the vehicle still collided violently with a concrete barrier at approximately 97 km/h, resulting in the unfortunate deaths of three people. This tragic event has once again thrust the safety concerns of new energy vehicles, particularly those equipped with autonomous driving technology, into the spotlight, prompting significant public scrutiny and reflection on their safety performance.
As the automotive industry rapidly transitions toward new energy and intelligent technology, questions arise about the safety levels of new energy vehicles and autonomous driving cars compared to traditional fuel vehicles. These concerns are not only critical for consumers but also essential for automotive manufacturers as they navigate technological development and product iterations. Furthermore, they represent significant challenges that must be addressed for the sustainable development of the automotive sector.
Comparing Collision Safety between New Energy Vehicles and Fuel Vehicles
The fundamental transformation in the power system of new energy vehicles leads to significant differences in collision safety design and considerations compared to fuel vehicles. New energy vehicles can be broadly categorized into those converted from fuel to electric and those built on dedicated electric platforms. The conversion models, which retrofit battery packs onto existing fuel vehicle chassis, often face challenges related to spatial layout, range, and weight distribution, ultimately impacting their collision safety performance negatively. In contrast, new energy vehicles built on electric platforms enjoy clear advantages in material selection and structural design. Many manufacturers invest significantly in high-strength steel and lightweight, high-strength aluminum alloys for critical areas, greatly enhancing the vehicle’s resistance to impacts during collisions.
Test results from the China Insurance Automotive Safety Index (C-IASI) support this perspective. For instance, the Aito M9 electric vehicle excelled in occupant safety tests, achieving “zero defects” in both the 25% offset collision and side impact tests, while also receiving excellent ratings for roof strength and seat/headrest conditions. This demonstrates the remarkable improvements in structural safety for new energy vehicles.
While there are similarities between new energy and fuel vehicles in standard collision tests, the high energy density batteries in new energy vehicles make battery protection a crucial factor in assessing collision safety. The battery, often referred to as the “heart” of the vehicle, can lead to significant operational failures and severe safety hazards like fire and explosions if damaged in a collision. To combat this challenge, the new energy vehicle industry invests heavily in numerous non-standard crash tests, simulating extreme conditions such as sharp object impacts on the vehicle’s underside.
Taking Tesla as an example, their innovative approach involves placing battery packs at the vehicle’s base, creating a robust and stable “chassis” structure that significantly enhances the overall rigidity of the vehicle and reduces the risk of direct impact and damage to the batteries during collisions.
Self-Ignition Safety: Comparing New Energy Vehicles with Fuel Vehicles
Historically, self-ignition incidents were relatively common with fuel vehicles, primarily due to issues like aging electrical systems, fuel leaks, and prolonged exposure to high temperatures. Statistics indicate that the self-ignition probability for fuel vehicles was quite high, with approximately 10 to 20 out of every 100,000 vehicles potentially experiencing such incidents. Fortunately, regular maintenance, adherence to proper driving protocols, and avoiding extreme conditions can help mitigate these risks, enhancing safety for drivers.
Conversely, the causes of self-ignition in new energy vehicles are more complex and diverse. Factors such as external impacts on battery circuits during regular use can lead to short circuits and potential self-ignition. Additionally, if the internal thermal management system of a battery fails, excessive heat generated during charging and discharging can lead to thermal runaway, ultimately causing the vehicle to ignite. Although statistics suggest that the self-ignition rate of new energy vehicles is lower than that of fuel vehicles, once a fire occurs, the rapid spread of flames and the difficulties in extinguishing them often result in far more severe consequences than those seen with fuel vehicle fires.
When a new energy vehicle ignites, intense chemical reactions within the battery can release significant energy, causing flames to reach extremely high temperatures. Standard fire extinguishers often struggle to combat such fierce flames, and the likelihood of re-ignition is notably high, posing substantial challenges for firefighting efforts. To fundamentally improve self-ignition safety, the industry has implemented various technical measures, such as using heat-resistant ceramic separators, explosion-proof valves, and current interruption devices (CID) in battery cells. These innovations ensure prompt and precise disconnection of electrical circuits during abnormal conditions, effectively preventing thermal runaway.
Debates often arise about which type of vehicle—new energy or fuel—is safer. Some individuals may perceive electric vehicles as more prone to self-ignition; however, a report from CCTV has provided compelling evidence to the contrary. According to statistics on the number of new energy vehicles and fire incidents over the past three years, the fire rate for new energy vehicles has decreased from 0.185 per 10,000 vehicles in 2021 to 0.096 in 2023. In comparison, the fire incidence rate for fuel vehicles hovers around 0.15 per 10,000 vehicles, indicating that the current fire rate for new energy vehicles is, in fact, lower.
Furthermore, data from Norway—one of the countries with the highest proportion of new energy vehicle sales—reveals that the fire incidence rate for gasoline and diesel vehicles is four to five times greater than that of new energy vehicles. In response to these findings, Dong Yang, chairman of the China Automotive Power Battery Industry Innovation Alliance, noted, “The fire accident rate for electric vehicles is statistically lower than that of fuel vehicles; however, our experience in handling electric vehicle incidents is not as robust as that for fuel vehicles.”
Battery Pack and High-Voltage System Safety Management
The safety management of battery packs and high-voltage systems is crucial for ensuring the stable operation of new energy vehicles. Poor management can lead to severe safety incidents such as self-ignition and electric leakage, endangering both personal safety and property. For instance, the New Yuan EV integrates various advanced technologies in its battery pack and high-voltage system management to establish a comprehensive safety protection system.
Within the battery pack, critical components like positive and negative contactors act as vigilant guardians, swiftly cutting off battery current output in the event of a collision or battery anomaly, thus preventing short-circuit-related incidents. Additionally, rigorous and regular testing of these contactors ensures their reliability and operational integrity.
In terms of high-voltage system protection, new energy vehicles leverage powerful software systems to achieve intelligent and precise safety measures. Technologies such as collision-disconnection enable the high-voltage circuit to be cut off within milliseconds during a collision, preventing potential injuries to occupants from high-voltage electricity. Furthermore, discharge technologies ensure that residual energy in the high-voltage system can be safely released during maintenance or fault situations, safeguarding the personnel involved.
In contrast, fuel vehicles do not have high-voltage systems, resulting in lower voltage in their electrical circuits, which reduces leakage risks compared to new energy vehicles. However, the fuel system in these vehicles requires careful maintenance; any leakage can pose a significant risk of fire if exposed to open flames or high temperatures.
Is Autonomous Driving Technology Reliable?
With the rapid advancement of technology, autonomous driving is gradually shifting from science fiction to reality, promising a more convenient and efficient travel experience. However, the serious accident involving the Xiaomi SU7 during NOA smart driving assistance has cast a shadow over the safety of this emerging technology, raising public concerns about the safety performance of autonomous vehicles.
From a technical standpoint, autonomous vehicles rely on sensors, cameras, radar, and complex algorithms to perceive their surroundings and make driving decisions. Ideally, these advanced technologies can provide high-precision environmental recognition and quick decision-making, effectively reducing the risk of traffic accidents caused by human error. For instance, some high-end autonomous vehicles equipped with LiDAR can construct a three-dimensional model of the surrounding environment in real-time, providing accurate distance information to help the vehicle anticipate potential dangers and take appropriate evasive actions.
However, the real-world traffic environment is complex and unpredictable, presenting significant challenges for autonomous driving technology. Adverse weather conditions, such as heavy rain, fog, or snow, can severely impact the performance of sensors and cameras, reducing their ability to accurately perceive the environment and potentially leading to misjudgments. Additionally, unclear traffic signs, temporary construction conditions, and non-compliant behavior from other road users can confuse autonomous driving systems, hindering their ability to make accurate and rational decisions.
While the current incidence of accidents involving autonomous vehicles remains relatively low due to their limited numbers, existing cases have raised significant concerns. For example, Tesla has experienced multiple collisions while its autonomous driving assistance system was active, resulting in severe injuries and property damage. These incidents highlight that, despite ongoing advancements, autonomous driving technology still has a long way to go before achieving full reliability and safety.
To enhance the safety of autonomous vehicles, the industry is actively implementing various measures, including increasing investment in research and development, optimizing sensor performance, refining algorithm models, and expediting the creation of safety regulations and standards for autonomous vehicles, which define safety requirements, testing specifications, and accident liability.
Conclusion
In summary, new energy vehicles, autonomous driving vehicles, and fuel vehicles each possess unique characteristics and face distinct challenges regarding safety. New energy vehicles demonstrate impressive competitive advantages and development potential in battery protection technology and intelligent safety configurations. However, ongoing research and development efforts are essential to address risks associated with self-ignition and to develop effective solutions for complex safety issues post-accident.
While consumer perceptions of safety differ between new energy and fuel vehicles, it is undeniable that the shift towards new energy vehicles is an irreversible trend. It is hoped that as the industry matures, tragedies caused by self-ignition will become a thing of the past.
