CCTV News (Focus Interview): China is the world's largest producer and user of electric bicycles, with a total of about 350 million electric bicycles and an annual output of about 35 million. Electric bicycles are convenient, efficient, and not too expensive, which greatly meets people's rigid needs for short-distance travel. However, in recent years, electric bicycles have also caused many accidents for various reasons, even causing casualties, which has aroused public concern. In addition to regret, people have once again focused their attention on the safety of electric bicycles.

A series of electric bicycle fire accidents occurred in various places. Although the causes are different, they often catch fire quickly, burn violently, release toxic and harmful gases, and even explode in serious cases, resulting in casualties and property losses.

Gao Weina, second-level commander of the Fire Supervision Department of the State Fire Rescue Bureau:"It will reach the burning state in 30 seconds, and the temperature at the center of the flame can reach 1200 degrees Celsius in 3 minutes. If it is indoors, the indoor temperature can be as high as 600 degrees Celsius, which will produce a lot of toxic smoke. At present, our country does not have a fire extinguishing agent specifically for electric bicycle fire fighting."

Experts said that lithium battery fires are quite different from ordinary fires. Lithium batteries are an energetic substance. Existing fire extinguishing agents, such as dry powder fire extinguishing agents, have almost no effect on lithium battery fire fighting; carbon dioxide and heptafluoropropane can only extinguish open flames, but cannot fundamentally suppress the occurrence of fires, and often reignite; although the water sprinkler system has obvious cooling and fire extinguishing effects, it consumes a lot of water and takes a long time to extinguish.

According to statistics from the China Bicycle Association, by the end of 2022, China's electric bicycle ownership was about 350 million, with an average of one for every four people. Therefore, even if the probability of an accident is very small, it is not a small number in absolute terms. According to statistics from the National Fire and Rescue Bureau, since 2021, China has received reports of 69,700 fires caused by battery failures in electric bicycles and buildings, 884 deaths and injuries, and direct property losses of more than 700 million yuan. So why are there so many fire accidents involving electric bicycles? Gao Weina: "Electrical failure is the main cause, accounting for 78%, of which battery thermal runaway accounts for 44%. First, the inherent safety of the whole vehicle and battery products is not up to standard, and the lithium batteries sold in the market are mixed, and many are even "three-no" products; second, the problem of illegal modification is prominent; third, electric bicycles are charged in buildings and households, causing mass deaths and injuries." The reporter conducted an investigation in Nanning, Guangxi. With the assistance of the traffic police, we randomly checked some vehicles and found several outstanding problems, the first of which was illegal modification of batteries. In order to run farther, the courier brother installed a spare lithium battery on the basis of the original lead-acid battery. Because the battery compartment was already occupied, he simply put the spare battery in the suitcase.

According to national standards, the battery should be fixed in a special battery pack box, the maximum gap between the battery and the side wall of the battery pack box is less than or equal to 30 mm, and it should not shake.

The courier not only used the suitcase to hold the battery, but also used foam and plastic bags to fix the battery. Not only that, he also changed the wiring and structure of the car. The investigation found that there are many people who illegally modified the battery. The main purpose of the modification is to run faster and farther.

In April 2019, the "Electric Bicycle Safety Technical Specifications", which is often referred to as the new national standard, was officially implemented. It stipulates that the maximum speed of electric bicycles shall not exceed 25 kilometers per hour; the total weight of the vehicle shall not exceed 55 kilograms; and the battery voltage shall not exceed 48 volts. However, many people believe that the new national standard cannot meet actual needs, especially high-frequency users such as takeout, express delivery, driver-on-behalf, small vendors, and enthusiasts, so they have modified them.

At present, there are more than 10 million riders in China who use electric bicycles as their operating tools. In order to run more and faster, some people often configure at least one spare battery, most of which are modified batteries. In order to adapt to the modified battery, the vehicle structure, size and line will also be modified. Although these practices violate national regulations, many people still choose to modify. Modifications are usually carried out at maintenance points. The reporter came to Zhonghua Road in Nanning, where maintenance points are concentrated.

Here the reporter saw: changing lead-acid batteries to lithium batteries and changing small-capacity batteries to large-capacity batteries are the modification requirements often raised by general car owners. Although these are all in violation of national regulations, they can all be changed at the maintenance point.

The battery voltage can be changed here at will, 60 volts, 72 volts or even higher.

The investigation found that original lithium batteries with the same power usually sell for thousands of yuan, while modified batteries are cheaper and only sell for a few hundred yuan, so many people will buy modified batteries, but it also buries potential accidents. The cells of modified batteries are usually second-hand cells eliminated from electric vehicles. However, black workshops pass off old batteries as new ones and inferior batteries as good ones. Safety protection is seriously lacking and does not meet national standards at all. However, on short video platforms, many businesses publicly display the battery modification process to attract business.

Faced with the chaotic modification market, the local market supervision and management department does not seem to have a good solution. Only 88 cases were investigated and dealt with last year.

Jiang Zhiying, head of the Law Enforcement Supervision Section of the Nanning Market Supervision and Administration Bureau of Guangxi:"Each modified vehicle is fined according to the standard of 1,000 yuan. For users, the market supervision department is more about education. Modifying electric bicycles, especially modifying the transmission and adding batteries, can be completed in a short time, about half an hour, which puts great demands on the time, frequency and intensity of daily supervision and inspection."

Modified batteries that do not meet national standards like this are prone to accidents. According to the Beijing Fire Rescue Corps, electric bicycle fires caused by battery failure account for more than 90% of the total number of accidents. Most battery failures are caused by illegal modifications.

As a comparison, let's take a look at how regular battery manufacturers ensure battery safety. First of all, in terms of battery cells, regular manufacturers use lithium iron phosphate batteries with higher safety.

Huangfu Dongyang, assistant to the chairman of a new energy company in Guangxi: "Because its structure is relatively stable, the battery performance is relatively stable. At the same time, a BMS system is added to it, and a battery management chip is implanted in the battery management system. By writing programs, the data of various electrical properties of the entire battery are extracted and controlled."

The BMS system is the battery management system, which is equivalent to the "brain" of the battery. It can even remotely manage each battery. These safety protection measures are not available for modified batteries.

Huangfu Dongyang: "Including the battery voltage status, remaining power, signal, etc. can all be displayed. In the case of high temperature alarm, the power can be cut off to reduce the risk."

Electric bicycles cause fire accidents not only because of the use of illegally modified batteries, but also because of the modification of the body, including the body structure, motor power, wiring, etc., but at the maintenance point, all of these can be modified. Even the "brain" of the electric bicycle, the controller, can be modified at will. There are countless videos of various modifications on the Internet.

Industry insiders said that replacing the original battery with a large-capacity battery may cause the technical parameters such as battery power and weight to be inconsistent with the parameters of the main components of the electric bicycle, such as the charger, speed controller, and motor. During charging and use, short circuits or thermal runaway may occur, causing fires.

Li Denghua, production process manager of an electric vehicle company in Guangxi: "Electric bicycles are not just a patchwork of parts. We must treat it as an overall design, including the rationality of the R&D structure, the rationality of the vehicle process layout, the high quality of the parts, and the rationality of the safety design of the parts, in order to ensure the safety of electric vehicles when leaving the factory, not just the battery problem."

In order to prevent modified batteries from causing fire accidents during charging, some charging pile companies have used technical means to restrict hardware to improve charging safety.

At present, China only has recommended standards for lithium-ion batteries for electric bicycles, but no mandatory standards. It is understood that the mandatory national standard "Safety Technical Specifications for Lithium-ion Batteries for Electric Bicycles" has passed the drafting and comment solicitation stages and will be issued soon.

Illegally modified electric bicycles are faster and run farther, but this comes at the expense of safety. Industry insiders pointed out that at present, there are no specific laws and regulations to constrain the illegal dismantling and modification of electric bicycles. Therefore, the punishment measures for illegal modification of electric bicycles can only be mainly administrative penalties, which is difficult to play a deterrent role. It is recommended to further improve laws and regulations and effectively play the restraining role of legal norms. Here, we would like to solemnly remind consumers to purchase regular and qualified vehicles and accessories, replace old batteries regularly, and do not modify electric bicycles illegally for the sake of temporary pleasure.

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