Is the electric car battery safe?

In 2015, China became the world's largest electric vehicle sales country, and people's concern about the safety of electric vehicles has also increased. From time to time, the reports of electric vehicles burning reports in the newspapers, and the radiation problems that individuals are worried about have poured in one after another, causing business troubles and confusing consumers.

Is the electric car safe, or rather, is the battery safe? Like gasoline tanks and oil products, its safety also requires rigorous testing and inspection. The reporter interviewed some companies and researchers.

Wang Chuanfu, president of China's BYD Co., Ltd., said: "This worry is superfluous. Our products are in line with national regulations ... Frankly speaking, our bus voltage is 750 volts. In fact, our friends in Beijing and Shanghai take the subway, the voltage of the subway is 1500 volts, almost double, take the subway do not worry about electromagnetic interference, so take our bus not to worry. So please rest assured that it is safe to ride the electric bus. "

Lihong, the chief scientist of the Chinese Academy of Sciences' lithium-ion battery project, said there was no objective basis for the rumors.

He said that the battery is powered by DC, theoretically, of course, electromagnetic radiation, but according to relevant standards and regulations, the outside of the battery is covered with materials used to shield radiation, and there should be no radiation leakage at the technical level. But it's also a problem if the car fails, such as a crash in the relevant part, which doesn't affect the operation, but there is a leak in the electromagnetic shield. For the solution, "go to the 4S store to maintain the vehicle and check the electromagnetic shielding situation. This is not difficult. Even the worried consumer can use a handheld device to detect it. "

For the safety limit of electromagnetic radiation, the WHO standard is calculated to be less than 100 μT(Weitesila) according to magnetic induction intensity, and China has also adopted this standard. Some countries have to be wider, such as the United Kingdom is 200 μT.

The safety of electric vehicle batteries is not only referred to as electromagnetic radiation. At present, there are 20 test entries for the safety of power cells in China, all of which can be passed on the road. The companies concerned are most worried about the battery heat out of control, pressure, fire, explosion. In system design, multiple safety guarantees should be set up by means of the battery management system, fuse protection, structure integration, etc.. In the process of matching the battery with the vehicle, it must also be fully certified by the durability experiment.

However, in practical applications, there are occasional cases of electric car fires. In December 2015, for example, an electric bus caught fire in Hong Kong, possibly because of a short circuit. Tesla, the "star" of electric cars, is expensive and supposedly safe, but in January a charging fire broke out in Norway.

Government departments have always attached great importance to the safety of electric vehicles. China's Ministry of Industry and Information Technology announced in January that it had suspended the listing of three lithium battery passenger cars for safety reasons. The ministry of industry and information technology said that three lithium batteries have high energy and good recycling performance, which is an important development direction for lithium batteries in the future. However, in this field, China started late and it is not enough for the safe development and verification of passenger cars. More safety assessment is needed. Pending the completion of the assessment, three lithium battery passenger cars will be suspended from the list of recommended models.

The mainstream lithium-ion batteries can be divided into various types such as lithium iron phosphate, lithium ternary, lithium manganese acid, and lithium nickel acid due to different materials. Researchers are developing new solid lithium batteries. It replaces the electrolyte from liquid to solid, which greatly improves its safety performance. For example, the Autoolib electric car introduced in Paris, France, uses solid-state lithium batteries. In one riot, a car was set on fire but the battery was found to be still there. Lihong said the case shows that the new battery has better safety.

In the increasing number of electric vehicles today, the absolute number of electric vehicle-related accidents may gradually increase. However, as with traditional gasoline vehicles, there will be some accidents. Concerned about the safety of electric vehicles should be considered more from the point of view of probability. Simply think that "the battery is fierce" is a great misunderstanding.

The page contains the contents of the machine translation.