New National Standards Aim to Make Electric Vehicle Battery Fires a Thing of the Past

Will spontaneous combustion of power batteries become a thing of the past? A new national standard mandates that batteries must be “bulletproof” by next year.

Recently, the Ministry of Industry and Information Technology released a mandatory national standard titled “Safety Requirements for Power Storage Batteries Used in Electric Vehicles”. This standard aims to reduce the occurrence of spontaneous combustion incidents in power batteries by focusing on product design.

Although the official implementation date is set for July 1st of next year, there has already been a noticeable increase in product testing and trials related to the new standard. At the New Energy Testing Center of the China Automotive Technology and Research Center, engineers are conducting a variety of complex tests on automotive power batteries. A responsible official noted that most of these tests are centered around the new national standard.

Jiang Chenglong, a senior engineer at the New Energy Testing Center, stated, “Since the release of the new national standard, major domestic vehicle and battery manufacturers have been actively applying for tests under this standard. Some companies have already received testing reports, and new products are primarily being tested according to the new regulations.”

Experts indicate that this new standard includes seven individual tests and 17 tests for battery packs or systems. Compared to the 2020 version, the new standard imposes stricter safety requirements on power batteries.

Hao Weijian, a senior engineer at the China Automotive Technology and Research Center, explained, “The safety requirements are more stringent, raising the alarms for thermal diffusion from five minutes before ignition and explosion to preventing ignition and explosion entirely. Additionally, the scope of testing has expanded, with specific tests designed for safety risk scenarios such as undercarriage impacts and prolonged fast charging.”

Three New Rigid Tests Strengthen Safety Measures

The new national standard introduces three rigorous tests, with thermal diffusion protection being a key component that significantly enhances battery safety.

The standard also includes tests for scenarios like undercarriage scraping and the widespread adoption of fast charging for new energy vehicles, ensuring comprehensive safety for power batteries.

Thermal diffusion refers to a situation where thermal runaway in a single battery cell triggers a chain reaction in other cells, potentially leading to fire or explosion. The new standard specifies that tests can be conducted using needle penetration or internal and external heating methods.

Reporter Luo Hongjin from CCTV noted, “During the needle penetration test, a 5mm steel needle will penetrate the target battery cell at a speed of 1mm per second, taking approximately 50 seconds to break through.” The reporter observed that once the target cell was pierced, smoke immediately emerged from the battery pack, and the temperature of the monitored cell surged.

Jiang Chenglong further explained, “Typically, the temperature of the punctured battery can rise to around 300°C, while the internal temperature may reach approximately 1000°C. During this process, the temperature of adjacent batteries will also increase, but the entire battery system must not catch fire or explode.”

Undercarriage scraping is an unavoidable occurrence while driving; thus, the new standard also adds a rigorous test for undercarriage impact.

Reporter Luo Hongjin added, “Here at the site of the battery pack bottom impact test, a 30mm steel impact head will strike the battery pack at a force of 150 joules on designated risk points, which include front, middle, and rear points beneath the battery pack.”

Jiang Chenglong explained that these three risk points were chosen for their sensitivity to the protective capabilities of the battery pack. The aim of the test is to assess how the battery pack responds to impacts.

Moreover, to address the rapid proliferation of fast charging for new energy vehicles, the new standard also introduces safety testing for batteries after fast charge cycles. This test targets battery cells charged within 15 minutes and includes external short-circuit tests after 300 fast charge cycles, ensuring that the battery cells do not catch fire or explode.

Multiple Extreme Tests Assess Power Batteries

After undergoing rigorous tests for thermal diffusion protection, undercarriage impact, and fast charge cycles, are electric vehicle power batteries deemed sufficiently safe?

In fact, they must pass numerous extreme tests to be deemed ready for deployment. This includes a battery pack simulated collision test, where the fully charged battery pack is secured on a test platform and subjected to collisions from two directions, ensuring no leakage or shell rupture occurs.

There is also a fire test where the battery pack is exposed to flames for 70 seconds and then indirectly burned for 60 seconds, during which it must not ignite or explode.

The water immersion test involves submerging the battery pack in one meter of water for 30 minutes, followed by a two-hour observation period to check for water ingress, ensuring no water intrusion, leakage, and normal insulation performance.

Additionally, the compression test uses a semi-cylindrical object with a 75mm radius, applying a force of 100 kN from two directions, requiring the battery pack to remain leak-free and not to ignite or explode.

Automakers Enhance Battery Safety Technology

Many automakers are reportedly increasing their innovation efforts to strengthen battery safety measures from multiple dimensions.

Full-chain technology upgrades are reshaping safety standards for power batteries. A representative from one automaker stated that they are actively conducting tests that exceed the new national standard, such as increasing undercarriage impact forces or extending thermal diffusion monitoring duration to better validate battery safety. They are also innovating in battery structure by employing a “blocking and channeling” management technique.

Zhao Yongpo, CEO of Great Wall Motors’ Haval brand, explained, “Blocking means diverting heat through safe pathways when localized thermal runaway occurs. For areas requiring sturdiness, such as those prone to bottom impacts, we use a ‘sandwich’ structure to ensure that our batteries do not experience thermal runaway during strong impacts.”

Another automaker’s representative shared that battery packs typically consist of hundreds of individual cells, and managing each cell effectively ensures the overall safety of the battery pack.

Li Jin, head of battery research and development at GAC Group, stated, “We utilize fireproof and heat-insulating materials to divide the battery pack into multiple ‘safety compartments.’ When thermal runaway occurs in a cell, the fireproof layer and heat-absorbing materials will contain the heat within the ‘safety compartment’ and quickly dissipate it through rapid cooling technology, ensuring that it does not affect other batteries.”

Additionally, some companies are choosing more stable material systems to enhance battery safety, such as high-safety positive electrodes, flame-retardant electrolytes, and high-heat-resistant separators to minimize the risk of thermal runaway in individual cells. Furthermore, cloud-based big data methods enable real-time diagnostics of battery health, allowing for early identification of potential faults.

Current National Standards Ensure Basic Safety for Vehicles

With the implementation of the new power battery national standard on July 1st next year, there will be a systematic enhancement in battery safety levels. However, some consumers are questioning whether they should wait for the new standard to purchase new energy vehicles.

In response, industry experts indicated that the current national standards already ensure basic vehicle safety, and many companies have proactively completed their technological preparations, allowing consumers to confidently select models that meet existing standards.

Experts emphasized that both the new and existing national standards uphold high safety levels.

Hao Weijian remarked, “Both the new and old standards have undergone thorough industry discussions and standard formulations, possessing a high technical level. Vehicles currently on the market already meet the relevant mandatory national standards, making them generally safe.”

During interviews, it was revealed that some manufacturers had preemptively prepared their technology to adopt safer batteries before the release of the new standard.

Hao Weijian noted, “Based on our preliminary research, over 80% of new energy vehicle manufacturers are equipped with technologies that prevent fire or explosion after thermal diffusion testing, indicating a high overall level of safety technology, so consumers need not worry excessively.”