China has the largest number of electric bicycles (e-bikes) in the world. However, the number of fire incidents caused by the e-bike batteries is alarming.
In recent years, e-bikes have become an important means of transportation in China due to their affordability and convenience. China’s CCTV, a Chinese state-owned media, reported that the annual sales volume of e-bikes exceeds 30 million, and the current number owned is close to 300 million.
CCTV data show that as many as 6,462 fires were caused by the bicycle batteries in China from January to July of this year alone.
At 3:00 a.m. on Sept. 20, a fire broke out in a residence in Tongzhou District, Beijing, killing the upstairs neighbors’ entire family of five. The cause of the fire was the lithium-ion battery from the family’s e-bike, which exploded and caught fire while it was being recharged in their apartment.
According to state media Dazhong Daily, since 2009, there have been more than 70 e-bike fire incidents in China that resulted in at least three deaths, combining to a total of nearly 400 deaths. On Apr. 24, 2018, a fire in Qingyuan City, Guangdong Province, killed 18 people, and on Sept. 25, 2017, a fire in Taizhou City, Zhejiang Province, killed 11.
The latest data from China’s Ministry of Emergency Management suggested that the leading causes of fires were electrical failure and spontaneous combustion from e-bike batteries, which accounted for 62.1 percent and 23.5 percent of the total number of e-bike fire incidents respectively. Overcharging, over-discharging, and short-circuiting are some of the primary causes of electrical failures in batteries.
According to public information, the two primary types of batteries used in electric bicycles in China are lead-acid and lithium-ion (Li-ion). Both types of battery are quite safe when manufacturing quality conforms to specifications and safety features are implemented.
Lead-acid batteries use sulfuric acid as the electrolyte, which is not easily flammable or combustible. Lithium-ion batteries are more widely used as they are light, hold more energy, last longer, and charge quickly. However, lithium batteries are also the cause of most e-bike fire incidents as they are sensitive to high temperatures and can burst into flames when their separators are damaged.
Liu Yanlong, Secretary of China Chemical and Physical Power Industry Association, told CCTV that most e-bike batteries manufactured in China might be substandard in terms of quality. Liu suggested that some refurbished batteries may have internal swelling and short-circuit problems, and long-term use of a battery can lead to aging and external short circuit. In addition, batteries with a malfunctioned or failed battery management system (BMS) may lead to overcharging and overheating.
Liu also pointed out that China’s “Lithium-ion Battery Specification for Electric Bicycles” is currently listed as “recommended” and not “mandatory.” In other words, e-bike companies can choose not to implement this safety standard.
China’s Ministry of Industry and Information Technology formulated a “Safety Technical Specification for Electric Bicycle” in 2019, but its standard is still low in the eyes of professionals. Zhang Yingzong, Emergency Management Department director of the Shenyang Fire Station, told Caixin Global, a Chinese state-owned media, that “[the Chinese authorities] didn’t adopt many expert suggestions when creating the regulations due to the concerns of cost.”
Starting Sept. 28, Beijing banned electric mobility tools from the subway. Beijing’s transportation department explained that bringing electric bicycles and other electric mobility tools on its subways could hinder its fire protection measures. In the case of a fire, the use of e-bikes and other e-mobility tools may block the passageways and affect evacuation, delaying the fire extinguishing efforts.
China’s “Fire Safety Regulations in High-Rise Buildings,” implemented on Aug. 1, banned parking or charging e-bikes in public hallways, evacuation walkways, stairwells, and safety exits of high-rise buildings.
“Behind all these regulations, the fact is, the quality of the batteries is not reassuring,” said CCTV host Bai Yansong on his program in late September.
