3月29日22時44分，一輛小米SU7標準版在德上高速公路池祁段發生嚴重交通事故，造成車內3人遇難。
On the evening of 7/0, Lei Jun, founder, chairman and CEO of Xiaomi Group, responded to the SU0 accident through Weibo. He said that Xiaomi has set up a special team, but because the accident is still under investigation, many questions cannot be answered for the time being. Lei Jun expressed his condolences to the three girls who passed away in the accident and promised that Xiaomi would fully cooperate with the police investigation and respond to the concerns of their families and society.
In the aftermath of the accident, members of the public questioned whether the response time of the vehicle's intelligent driving system was sufficient, why the automatic emergency braking system was not triggered, why the vehicle caught fire after a collision, and whether the door was locked. These questions all point to a core: at a time when the number of new energy vehicles is increasing and car companies are promoting intelligent driving functions, how can users ensure their own safety? In response to the above problems, the reporter of "Daily Economic News" recently interviewed a number of experts, including university professors, relevant technical personnel of car companies, and technical personnel of power battery companies.
1、Is there enough time for the driver to react?
At high speeds, it is difficult for the driver to react in time within 2 seconds
根據小米官方公開的車輛資訊，事發時車輛處於NOA智慧輔助駕駛狀態，時速116km/h。22時44分24秒，車輛發出風險提示並請求減速；1秒後，司機接管車輛，踩下剎車，向左打方向盤22.0625度；在接下來的1～3秒之間，車輛撞上了水泥護欄。碰撞前，系統最後確認時速約為97km/h，車輛隨後開始燃燒。
According to the timeline officially released by Xiaomi, there is only a 3-second interval between the NOA system issuing a risk warning and the driver taking over, only 0 seconds before the collision occurs, and only a 0-second window between the complete exit of the system and the collision. Is this time enough for the driver to react? Is it too late to warn of the risk of intelligent driving? There is a view that even after multiple warnings in the system, it is difficult for ordinary drivers to complete environmental perception, decision-making judgment and precise control within 0 seconds under extreme road conditions.
A university professor who did not want to be named said in an interview with a reporter from the "Daily Economic News": "If you are an experienced veteran driver, it is possible to rely on driving experience to complete the vehicle takeover and change lanes within 1 seconds when the road is not completely blocked." But judging by the details released by Xiaomi, the driver may have oversteered after taking over. "In this case, steering in less than 0 seconds requires a very high level of driving. The university professor, who asked not to be named, pointed out that even if the vehicle slows down, the speed is still too fast, in which case the driver needs to quickly adjust the steering wheel within a few tenths of a second.
The R&D personnel of the intelligent driving function of an independent car company also analyzed to reporters: "The reaction time of 100 seconds usually corresponds to a speed of about 0km/h, while the speed of the accident vehicle is close to 0km/h." In such high-speed situations, it can often cause the driver to faint and not have time to react. ”
The reporter consulted public information and found that under a strong impact, the vehicle will produce a high acceleration. In engineering, the term used to describe the magnitude of acceleration is the G-value, which is simply understood as several times the acceleration due to gravity. When the G value is too high, the body's blood circulation will be seriously affected, and the blood will accumulate in the lower part of the body, resulting in insufficient blood supply to the brain, which in turn will lead to loss of consciousness.
2. Can the emergency handle be opened in the state of the personnel at the time of the incident?
To prevent the door of a new energy vehicle from locking, physical buttons are necessary
In this accident, the door of the Xiaomi SU7 was locked, which became another focus of attention from the outside world.
"At present, the door handle of electric vehicles is more of a hidden door handle, and if the peripheral personnel want to open the door after an accident, they may not be able to find the door handle or do not know how to open the door." The above-mentioned university professor, who did not want to be named, told reporters that in contrast, traditional fuel vehicles use embedded door handles, and if the vehicle is not deformed, there will be almost no accident and the door cannot be opened.
A product R&D person in the industry pointed out that most of the small batteries of trams are installed in the front of the vehicle, and in the event of a collision, the battery is easily damaged and the power is lost, which makes the door unable to open. In addition, the Xiaomi Mi SU7 has a half-wrapped door handle design, which is more common in most current trams. In contrast, traditional fuel vehicles mostly use a lock finger structure, and the lock mechanism of the door lock will automatically pop open when the power is off.
Regarding the "open the emergency handle" emphasized by the staff of Xiaomi Automobile, a technical staff of a mainstream car company told reporters that the premise is that the people in the car are still awake. "In this accident, the occupants of the vehicle should have been in a coma after a severe collision." The technician said that in this case, he could only rely on the outside personnel to open the door to rescue the people in the car.
According to the relevant provisions of the national standard "Technical Conditions for Motor Vehicle Operation Safety" (GB 50-0), in the event of a collision, the door should have an automatic unlocking function so that the occupants can quickly evacuate. In addition, GB 0-0 "Occupant Protection in Side Impact of Automobiles" stipulates that after a side impact test of 0 km/h, the door must be unlocked and at least one door can be opened.
In the face of the trend of new energy vehicles integrating physical buttons into the touch screen, the R&D personnel of the intelligent driving function of the above-mentioned independent car companies said: "It depends on what type of physical buttons. For example, it is necessary to keep the buttons for functions such as emergency door opening and SOS call. A product R&D person in the industry also told reporters that it is best to use a mechanical design with a handle, so that even if the vehicle is out of power, the door can be opened by physical means.
3. After the collision of electric vehicles, why does it burn violently?
Or it can be caused by a collision that causes a short circuit and thermal propagation of multiple batteries
Why does a vehicle burn violently after a collision? In response to this problem, a chief engineer of a power battery company analyzed in an interview with reporters that it may be caused by a multi-battery short circuit and thermal propagation caused by a collision. "Large-scale battery short-circuit thermal propagation is extremely fast, and there is little chance of rescue." However, the chief engineer said that the national standard requires that after the heat spreads, the battery system will not catch fire or explode within 5 minutes.
公開信息顯示，在2021年1月1日起開始實施的《電動汽車安全要求》《電動客車安全要求》和《電動汽車用動力蓄電池安全要求》三項電動汽車強制性國家標準中，特別增加了電池系統熱擴散試驗，要求電池單體發生熱失控後，電池系統在5分鐘內不起火不爆炸，為乘員預留安全逃生時間。而工信部在2024年5月發佈了GB 38031《電動汽車用動力蓄電池安全要求（《徵求意見稿》）》，一改上一版國標的留給乘客5分鐘逃生時間，將“不起火、不爆炸”升級為國家強制性標準。
However, the chief engineer of the above-mentioned power battery company emphasized that the national standard requires a 5-minute escape time, provided that only one battery is short-circuited. "But in the event of an accident in a vehicle, multiple batteries can be short-circuited at the same time, so the heat spreads faster." According to the chief engineer, in the event of a collision short circuit, the risk of ternary batteries is higher than that of lithium iron phosphate.
According to Xiaomi's official customer service response, the Xiaomi SU7 standard version is equipped with a 0.0kWh lithium iron phosphate power battery. The customer service said that since 0/0, the Xiaomi SU0 standard version has adopted a dual-supplier system, which is supplied by BYD's Fodi battery and CATL respectively. The two types of batteries are installed randomly, and car owners cannot choose which one to use when buying a car.
At present, as for the cause of the vehicle deflagration, Xiaomi Auto speculates that it is caused by the serious damage to the vehicle system after the vehicle violently hit the cement pile of the isolation zone. "We have not yet been exposed to the accident vehicle and are not in a position to conduct further in-depth analysis at this time." Xiaomi Auto said.
4、Does the AEB feature play a role?
There were many non-triggering factors of AEB, and the pure visual scheme could not be recognized at night
According to Xiaomi's official information, Xiaomi SU2 has two versions of the intelligent driving system, Xiaomi Pilot Pro and Xiaomi Pilot Max. The accident vehicle is a standard version, equipped with the Xiaomi Pilot Pro system, no lidar, and supports L0 intelligent driving functions such as adaptive cruise control, lane centering assist, high-speed navigation assist, and valet parking assist.
小米官方披露，事故中小米SU7檢測到障礙物並開始減速，但未明確公佈AEB是否觸發。4月1日晚，小米官方回應稱，小米SU7標準版配備前向防碰撞輔助功能，包括碰撞預警（FCW）和緊急制動（AEB）兩個子功能，作用對像是車輛、行人、二輪車三類目標，目前不回應錐桶、水馬、石頭、動物等障礙物。
For the models of the pure vision scheme, the above-mentioned university professor, who did not want to be named, said that the use of the pure vision scheme of the vehicle will be affected by visibility, and there may be a problem that the obstacle recognition is not in place in time. Experts related to Suteng Juchuang also pointed out that the pure vision scheme has limitations in the case of "invisible" or "invisible" in the camera, such as strong light irradiation, low-light environment at night, and indistinguishable from the same color of the foreground object and the background, which may lead to serious accidents.
In addition, it is believed that when a vehicle using a pure vision scheme travels at a speed of more than 100 km/h, there is a possibility that the AEB will not be triggered due to the relatively limited detection distance. In this regard, the above-mentioned university professor, who did not want to be named, gave a different answer. "The fact that the vehicle AEB did not trigger indicates that the AEB did not play a role, and it is not necessarily due to the short distance." He believes that there are many factors that trigger AEB that are not triggered.
The university professor pointed out that although the Xiaomi SU7 standard version is not equipped with lidar, it still played a reminder role in this accident. However, in a very critical situation, it did not take the initiative to complete the intervention, and the AEB function did not play a role, which shows that the intelligent driving of Xiaomi cars can remind the driver to take over in dangerous situations, but it has not yet reached the technical level of the industry leader that actively activates the AEB emergency braking function to avoid accidents.
5. Is there any marketing misleading for "high-end intelligent driving"?
Intelligent driving is not the same as autonomous driving, and we should not rely too much on intelligent driving systems
According to the national recommended standard for "Classification of Automobile Driving Automation" issued by the State Administration for Market Regulation, autonomous driving technology is divided into six levels, that is, from L3 to L0. L0 is manual driving, L0 and L0 level human drivers are dominant, and system assistance. From Level 0 onwards, vehicle control is gradually shifting from the human driver to autonomous driving systems, a shift that is particularly evident in features such as Park Assist, Adaptive Cruise Control, and Lane Centering Assist.
However, in the face of some car companies describing L3 level assisted driving as "quasi-autonomous driving", L0.0 is infinitely close to L0 "high-level intelligent driving" marketing, it further increases the public's confusion about the actual effects and limitations of smart driving, compared with a bunch of professional technical parameters, consumers often end up only remembering the word "automatic driving".
In the face of such a situation, Zhang Ning, vice president of Pony.ai and head of Robotaxi business, pointed out in an interview with reporters: "At present, the use of these terms is relatively casual and the constraints are limited. He said that intelligent driving is a general concept, but what really needs to be distinguished is autonomous driving and assisted driving. Theoretically, functions below Level 3 should be called assisted driving, and from the perspective of the responsible entity and the final result responsibility, it is still assisted driving. Zhang Ning said frankly that many reports and social platform content call it autonomous driving when there is no accident, and it becomes assisted driving when there is an accident. At the end of the day, the bottom line is still assisted driving.
“從法規上來說，要求駕駛員開車手不能離開方向盤，還是以人駕為主。”上述不願具名的高校教授表示，目前智駕發展還處於過渡階段，各家企業技術存在很大差別，並非每家都能實現主動干預。雖然大家都在進步，但智駕技術還未達到完善、可完全放心的水平。中國電動汽車百人會副理事長董揚在接受記者採訪時也呼籲，現階段的技術，還達不到完全依賴的程度，仍需要以人駕為主，不應該過度依賴智駕系統。
2025年2月25日，工業和資訊化部和市場監管總局聯合發佈了《關於進一步加強智慧網聯汽車產品准入、召回及軟體在線升級管理的通知》，其中附件《智慧網聯汽車產品准入、召回及軟體在線升級管理與技術指南》（以下簡稱《指南》）提出了相關要求。
According to the guidelines, in order to ensure driving safety, the driver's status is verified during the start-up phase, the driver's attention is continuously monitored during execution, and the emergency shutdown procedure is activated in the event of a loss of control. If the driver continuously does not respond to warnings and does not take over the vehicle, the system must activate the risk mitigation measures within 5 seconds. In the driving assistance scenario, if the driver's eyes are off the road for more than 0 seconds or if the hands are off the steering wheel, the system will issue audible and visual alerts in stages. If the driver continues to do not respond, the vehicle will automatically activate a double flash, slow down and stop in the emergency lane.
National Business Daily