Shortly after being involved in the "fire incident", Li Auto urgently recalled 11,411 units of the MEGA.

Recently, Beijing Li Auto Co., Ltd. recalled 11,411 electric vehicles of the 2024 MEGA model, with production dates ranging from February 18, 2024, to December 27, 2024. For the vehicles within the scope of this recall, due to the insufficient anti - corrosion performance of the coolant in this batch, under specific conditions, it may cause corrosion and leakage of the cooling aluminum plates of the power battery and the front motor controller in the cooling circuit, resulting in the vehicle's fault light being illuminated, power limitation, and the inability to power on. In extreme cases, it may cause thermal runaway of the power battery, posing a safety hazard.

Beijing Li Auto Co., Ltd. will replace the coolant, power battery, and front motor controller for the vehicles within the recall scope free of charge.

This recall of over ten thousand vehicles has once again pushed the spontaneous combustion incident of the Li MEGA that occurred on an elevated road in Minhang District, Shanghai, a few days ago, to the core of public opinion.

Li Xiang, the CEO of Li Auto, reposted the recall statement of the 2024 Li MEGA and stated: "This is an active recall. The accident investigation takes time, and sometimes it may take one or two months to get the results. We have already discovered the hidden danger that led to the accident. We can't wait when facing a one - in - ten - thousand risk. The probability of an accident may be one in ten thousand, but life is only once, which is 100%."

On the evening of October 23, at the intersection of Hechuan Road and Caobao Road in Minhang District, Shanghai, a pure - electric MPV of the Li MEGA suddenly caught fire while in motion. Eventually, the vehicle was burned down. Fortunately, the two people in the car escaped in time, and no casualties were caused.

After the incident, the car owner entrusted a law firm to issue a statement stating that while the vehicle was in motion, there was an explosion - like noise from the chassis, and then the car was filled with smoke. The electric rear - door couldn't be opened at first, and they finally escaped through the front - passenger door. The statement also pointed out that the online rumors such as "the battery pack was bumped", "the small battery was modified", and "the vehicle had a fault before the accident but was not repaired" were all false information.

This accident is not an isolated case. Within the past two weeks, there have been three new - energy vehicle fire incidents caused by different reasons. However, different from the other two cases involving collisions, this Li MEGA suddenly caught fire during normal driving, which has triggered extensive public discussions on the safety of power batteries in new - energy vehicles.

Against the background of the rapid development of the industry, the market penetration of new - energy vehicles continues to rise. The iterative upgrade of power - battery safety technology and the improvement of the standard system have become key issues that the entire industry urgently needs to address.

Analysis of the Causes of Thermal Runaway: Multi - dimensional Hidden Dangers from Cells to Systems

According to public information, the involved vehicle uses the Kirin 5C battery, which is a ternary lithium battery. As of now, the cause of the fire of this Li MEGA has not been announced.

“The technical causes of spontaneous combustion accidents in power batteries involve a complex chain of cells, components, and system management. It's difficult to directly identify the cause from the currently disclosed information.” An industry insider with many years of experience in the power - battery industry told a reporter from IT Times.

“Component short - circuit is one of the most likely direct causes of power - battery fires.” The industry insider said that in a complex battery management system, various electrical components such as connectors, relays, and resistors may short - circuit due to factors such as processing defects or long - term vibration, which will instantly generate a large amount of heat and then trigger thermal runaway. Especially when the vehicle is in motion, if the insulation parts fall off, it is very easy for components with different potentials to come into direct contact, forming a short - circuit loop.

The above - mentioned industry insider further analyzed that the failure of insulation protection may be another important cause. The power - battery system has extremely high requirements for insulation performance. All relevant insulation measures are strictly tested before leaving the factory, and theoretically, there should be no problems with the products that have passed the tests. However, as the vehicle is used for a longer time, affected by factors such as road conditions and temperature, the insulation materials may age, break, or fall off, which may lead to a leakage path between the cells and external conductive parts, causing an arc or even a fire under specific working conditions. “The failure of insulation is highly concealed. This kind of hidden damage that occurs during use may suddenly trigger a safety risk at a certain point in time.”

The relevant faults of the battery management system (BMS) are considered to be a highly possible cause by the industry. Although the control logic of the BMS has been verified to be basically reliable over a long period, problems may still occur in this system, mainly concentrated in two aspects: hardware damage and software bugs. At the hardware level, the BMS circuit board needs to undergo delicate processing such as surface - mounting, and components such as diodes and resistors inside may be damaged, and the temperature - sensing elements may also fail. At the software level, if there are bugs, it will also affect the system's functions.

“The BMS is like the 'nerve center' of the battery. Once there is a deviation in its monitoring of the cell temperature and voltage, it may miss the best opportunity to intervene in thermal runaway.” The above - mentioned person analyzed.

Hidden damage in the cells themselves may also be a potential cause of spontaneous combustion, but the probability is relatively lower, and it is not a common problem at the factory - production stage. The person believes that after the cells are assembled into a battery pack, they will undergo strict charge - discharge and insulation tests, and theoretically, problems with the cells themselves can be ruled out. There is only a very small probability of a “missed case” - a cell with microscopic damage may gradually expand the damaged area after multiple charge - discharge cycles, eventually leading to an internal short - circuit.

It is worth noting that it is often difficult to restore the exact state of the vehicle before the fire after it burns. “A long - time fire will eliminate some short - circuit traces before the fire, and it is extremely difficult to trace the exact location where the short - circuit occurred.” The industry insider said that this may pose considerable challenges to the investigation of the accident cause.

Currently, the analysis of accidents mainly relies on the fault records of the vehicle's CAN (Controller Area Network) bus. However, this kind of data can only reflect the system alarm information and cannot fully restore the microscopic changes at the moment of the fire.

The Arrival of the “Strictest - Ever” New National Standard

“Upgrading the collision tests in the test environment is of utmost importance.” An engineer who has been engaged in the R & D of complete vehicles for many years in an automobile brand told a reporter from IT Times. Currently, the testing requirements for new - energy vehicles still have certain limitations. Dynamic tests simulating real - world working conditions such as frequent fast - charging, long - time high - speed driving, and high - temperature and high - humidity environments need to be supplemented. The cycle life and safety performance under extreme collision conditions should be included in the core assessment indicators.

The arrival of the “Safety Requirements for Traction Batteries of Electric Vehicles” (GB 38031 - 2025) (hereinafter referred to as the “new national standard”) has greatly made up for this deficiency. This new national standard, which will be officially implemented on July 1, 2026, sets up the “strictest - ever” safety threshold with 24 test standards, which is fundamentally different from the previous standards.

The new national standard has achieved multi - dimensional safety upgrades: the thermal - diffusion test has been upgraded from the previous “5 - minute escape alarm” to “no fire or explosion within 2 hours”. A new “internal heating” triggering method has been added, and the state - of - charge (SOC) value during the test is required to be no less than 95%, which is closer to real - world usage scenarios. For the first time, a bottom - impact test has been included, where the entire bottom of the battery is impacted with an energy of at least “150 joules ± 3 joules” to test the chassis protection ability. In response to the trend of ultra - fast charging, a short - circuit test after 300 fast - charging cycles has been added to address the long - term safety hazards of ultra - fast charging. These three core requirements were not covered in the previous version.

Source: Ministry of Industry and Information Technology

In addition, enterprises need to optimize the testing system and upgrade the production lines simultaneously. At the testing end, a full - chain verification system from “cells - modules - systems” needs to be established. On the basis of meeting the mandatory requirements of the new national standard, dynamic tests simulating actual road conditions should be added. The production lines need to complete technological transformation in advance, and the models that have obtained type approval need to be adapted by July 1, 2027. At the same time, the new national standard incorporates the results of international standards such as UN R100, and enterprises need to meet both domestic and international compliance requirements.

In the next 3 - 5 years, the new national standard will promote the industry's transformation from “passive protection” to “active prevention and control”.

Risk Hedging under the Trends of High Energy Density and Ultra - Fast Charging

Currently, the new - energy vehicle industry is accelerating its iteration towards high energy density and ultra - fast charging. Technical claims such as “a 10 - minute charge for a 500 - kilometer range” and “a peak power of over 500 kilowatts” are frequently seen at press conferences of various automobile manufacturers. The supporting high - voltage platforms and fast - charging piles are also gradually being rolled out, becoming the core selling points for automobile manufacturers in the competition.

Li Auto has also claimed that the power batteries used in its models have “already met in advance” the safety, thermal - diffusion, and bottom - impact test requirements of the new national standard after fast - charging cycles. However, whether the test data in the laboratory environment can fully match the real - world scenarios of long - term, high - frequency fast - charging and driving on complex roads still needs time to verify.

Some experts have pointed out that high energy density means a higher proportion of active materials inside the cells, resulting in relatively lower thermal stability. Ultra - fast charging requires the battery to withstand a large - current input in a short period, which is likely to cause uneven lithium - ion migration, the formation of lithium dendrites, and will also intensify the “breathing effect” of the battery, accelerating the rupture of the solid - electrolyte interphase (SEI) film and the consumption of active materials. Long - term use may increase safety hazards.

How to balance performance breakthroughs with safety has become an issue that the entire industry must face.

The special tests for ultra - fast - charging safety in the new national standard are a forward - looking response to this trend. The standard - setters have realized that ultra - fast charging is not only an improvement in energy - replenishment efficiency. The industry also needs to address the cumulative damage to the battery caused by long - term large - current input. The standard upgrade will force the technology side to accelerate innovation.

In the current era of excessive publicity, automobile manufacturers should also abandon the obsession with “parameter - based marketing” and disclose long - term verification information such as test conditions and cycle - attenuation data, so that the performance advantages in the publicity can form a closed - loop with the actual safety performance, avoiding over - publicity that may mislead consumers.

Photos / Li Auto, Ministry of Industry and Information Technology, Doubao AI

This article is from the WeChat official account “IT Times” (ID: vittimes), author: Mao Yu. Republished by 36Kr with permission.