Nanjing Fire Triggers Concern Over Battery Powered Cars and Bikes

The Nanjing fire reminded the public of electric vehicles, known as new energy vehicles, which the Chinese authorities have vigorously promoted for years.

A food delivery driver wearing a face mask rides an electric bicycle across a street in Beijing on June 19, 2020. Wang Zhao/AFP via Getty Images

A residential neighborhood in China suffered a devastating fire caused by an electric bicycle, resulting in a significant loss of life. This has sparked concerns about the safety of batteries used in electric bicycles and cars.

Around 4 a.m. on Feb. 23, a fire broke out in a 34-story building in Nanjing, the capital of China’s Jiangsu Province. Online videos showed thick smoke and flames billowing from the building, spreading across several floors.

The building on fire was a residential neighborhood in the local Yuhuatai District called “Mingshang Xiyuan.” It wasn’t until daylight that the fire was extinguished, but the exterior walls still bore charred marks.

On Feb. 24, the local authorities reported that the fire incident had resulted in 15 fatalities and 44 hospitalizations, including one in critical condition and another in serious condition.

According to Liang Jun, the captain of the Nanjing Fire Rescue Brigade, the fire originated from the electric bicycle parking lot at the elevated ground level in Building 6. However, the specific cause is still under investigation.

Electric Bicycle Fires Not Uncommon

Fires caused by electric bicycles are not an occasional occurrence in China. According to statistics from the National Fire and Rescue Bureau of China, there were 21,000 reported cases of electric bicycle fires nationwide in 2023, an increase of 17.4 percent from 2022. In 2022, there were 18,000 cases, a year-on-year growth of 23.4 percent.

The National Fire and Rescue Bureau also pointed out that since many electric bicycle fires did not ignite surrounding objects and most people involved did not report them, the actual number is likely higher than reported.

Statistics show that 80 percent of electric bicycle fires occur when the device is charging. Despite China’s implementation of the “Fire Safety Management Regulations for High-rise Civil Buildings” in August 2021, which explicitly prohibits parking or charging electric bicycles in public hallways, evacuation corridors, stairwells, or safety exits of high-rise civil buildings, many still bring electric bicycles or batteries into buildings to be charged. The residential neighborhood where the fire broke out is a case in point.

In fact, this particular residential neighborhood experienced a fire a few years ago. According to a report by Nanjing Radio and Television Station in April 2022, a fire occurred in Building 2 of Mingshang Xiyuan in 2019, which was also caused by an electric bicycle. An owner said to have counted over 180 electric bikes parked on the elevated ground floor at 8 p.m. The fire destroyed more than 20 households. Luckily, since it happened during the day, there were no casualties.

Why Electric Bicycles are Prone to Fire

Regarding why electric bicycles are prone to fire, Xiang Guanyu, a station chief of the Wuhan Fire Rescue Brigade, told local media that there are three main reasons:

1. Overcharging, which can cause batteries to overheat, swell, or even explode

2. Aging wiring. Prolonged use of electric bicycles can lead to aging and loosening internal wiring, resulting in leakage, poor contact, or short circuits.

3. Improper use of chargers, such as mixed use of charging equipment for different brands of electric bicycles, which can damage batteries. Chargers must match the battery model.

Chen Guoliang, director of safety at Lan Tu Automotive in Wuhan, added that if batteries are subjected to external force or self-modifications, resulting in abnormalities or leakage, it can also cause fires and explosions. In addition, the unauthorized connection of electric wires poses significant safety hazards, as household chargers and sockets are not designed for continuous high-current charging and can easily overload, leading to fires.

Workers manufacturing electric bicycles at a factory in Huaian, Jiangsu Province, China on May 26, 2019. Reuters

Poor-quality batteries are also a significant factor in fires. According to a report by China’s State Administration for Market Regulation released last year, the failure rate of electric bicycle batteries reached as high as 21 percent.

Furthermore, the declining use of safer lead-acid batteries and the increasing dominance of easily flammable and explosive lithium batteries are related to official regulations.

Lead-acid batteries have long dominated the Chinese electric bicycle market. They are cheap and contain sulfuric acid as the electrolyte, making them less prone to self-ignition and explosion. However, they are heavy, have limited capacity, and have a shorter lifespan, generally lasting up to 400 deep charge and discharge cycles.

In 2018, China’s State Administration for Market Regulation introduced the “national standard” for electric bicycles, stipulating that the maximum design speed of electric bicycles should not exceed 25 kilometers (15.5 miles) per hour, the nominal voltage of batteries should not exceed 48 volts, and the total weight of the vehicle (including the battery) should not exceed 55 kilograms (121 lbs).

In terms of weight, a 48-volt 12-amp-hour lead-acid battery weighs around 16 kilograms (35 lbs). This means that using lead-acid batteries requires sacrificing range. In contrast, lithium batteries of the same capacity weigh only about 4 kilograms (8.8 lbs), with higher energy density and shorter charging times. Therefore, after the introduction of new regulations, lithium batteries quickly penetrated the market.

Safety Concerns About Electric Vehicle Batteries

The Nanjing fire reminded the public of electric vehicles, known as new energy vehicles, which the Chinese authorities have vigorously promoted for years.

The current mainstream types of new energy vehicles’ power batteries include lithium iron phosphate and ternary lithium batteries. Both are lithium batteries.

Electric vehicles tend to be much heavier than internal combustion engine vehicles due to the large number of batteries providing their power. Thomas Soellner/Shutterstock

Although less visible in the media, the number of fires involving new energy vehicles is also significant. According to statistics from emergency management departments, in the first quarter of 2023 alone, the self-ignition rate of new energy vehicles increased by 32 percent, with an average of eight new energy vehicles catching fire (including self-ignition) daily.

At the China Electric Vehicle Hundred People Conference in Beijing in April 2023, Sun Shigang, an academician of the Chinese Academy of Sciences, stated that lithium-ion batteries face several major challenges, including frequent safety accidents. He revealed that there were about 3,000 cases of new energy vehicle fires in China in 2021.

According to statistics from the YouTube channel “Insight into China,” hundreds of videos on Douyin, the Chinese version of TikTok, show the spontaneous combustion of electric vehicles from BYD, a well-known Chinese brand.