Some misconceptions about lithium-ion batteries

Regarding the "toxicity of lithium batteries", Liu Haojie, a researcher-level senior engineer of the 18th Research Institute of China Electronics Technology Group, said that the lithium-ion battery itself does not contain highly toxic substances, and the carbon of the negative electrode and the metal oxide of the positive electrode are basically non-toxic. Since lithium-ion batteries are a sealed system, they are not exposed to normal use. “In any case, its impact is much smaller than the most widely used lead-acid batteries.”

Lithium batteries have short life and harsh conditions?

Response: Power lithium-ion battery life can reach 2000 cycles, battery management system can limit "overcharge and over discharge"

How long is the current life of lithium batteries? Will shallow charge and overcharge and overcharge affect battery safety and life?

"There are many factors that determine the service life of a power lithium-ion battery, including the characteristics of the system itself, as well as the manufacturing process, working conditions, etc. High-quality battery system, plus scientific system management, can achieve a long service life." Wang Fang said that according to the capacity attenuation to 80% as the cut-off condition, according to the 100% discharge depth test, the current life of the power battery can basically reach 2000 cycles.

“Overcharge and over-discharge refers to the battery's voltage exceeding or lower than the specified cut-off voltage during charging and discharging, which will cause harm to battery performance and life.” Wang Fang said, but the BMS battery management system in the battery will be limited and protected. Restrict the charging of the battery at low temperatures and recharge when heated to a suitable temperature. Wang Fang said that in order to ensure the safety of lithium-ion batteries, there are a series of safety protection designs from battery cells, modules and battery systems to prevent over-charge and over-temperature of the battery, and to alarm and protect in case of abnormality.

According to the net text: There have been reports in the media that “Tianjin 18 has proved that lithium batteries have burned and exploded in almost all projects under high temperature and high pressure, puncture impact, overcharge and over discharge”.

In this regard, Liu Yanlong, secretary general of the China Chemical and Physical Power Industry Association, said that at the end of May 2014, the 18th Research Institute of China Electronics Technology Group was interviewed by the media, but the phenomenon of battery explosion in the program was based on the recording requirements of the program. After the protection circuit was removed, the abuse experiment was performed. The main purpose of this experiment is to let the users know the dangerous situation that may occur under the abuse condition of the ternary lithium battery without protection measures.

"The safety of lithium-ion batteries is theoretically controllable, and the safety problems are mostly caused by product defects and abuse." Liu Yanlong said. "But the safety of battery cells, modules and systems is not enough to ensure the absolute safety of electric vehicles equipped with lithium batteries." Li Ping, chairman of Ningde Times New Energy Technology Co., Ltd. (CATL), introduced the current model. —S used 7104 Panasonic ternary lithium batteries, which made great efforts in battery safety protection, including setting sensors, controlled by battery control system, and collision protection of materials such as high-strength aluminum alloy. With these safety designs, the probability of a security incident is still one in ten thousand.

Wang Qinghua, a researcher-level senior engineer of the 18th Research Institute of China Electronics Technology Group, also pointed out that the current products in the electric vehicle battery market are mixed, and the batteries produced by some manufacturers have poor consistency, and the effectiveness of the management system is not significant. Problems can have a certain impact on the overall life of the battery pack. In this regard, Wang Qinghua suggested that the government raise the corresponding test verification standards and strengthen the management supervision and testing of the electric vehicle market.

Waste lithium battery pollution is uncontrollable?

Response: Due to the relatively small environmental risks, lithium batteries have not been included in hazardous waste management, but the recycling system should be laid out as soon as possible.

Is there a mandatory recycling policy for lithium batteries? Is it like the online biography article, the waste lithium battery will cause huge environmental pressure? Wang Fang said that the waste batteries that were included in the hazardous waste management by the environmental protection department at this stage include waste nickel-cadmium batteries and waste lead-acid batteries. For disposable batteries, lithium-ion batteries, nickel-metal hydride batteries, etc., because their environmental risks are relatively small, they are not included in the management of hazardous waste.

However, the waste lithium-ion battery enters the environment, and the reaction of the electrode material, the electrolyte and other substances in the environment may cause heavy metal ion pollution such as nickel, cobalt and manganese, fluorine pollution and some organic matter pollution. So, are these pollutions controllable?

Wang Fang said that for the treatment of lithium-ion batteries, the "Recycling and Utilization Policy for Electric Vehicles for Electric Vehicles (2015 Edition)" drafted by the National Development and Reform Commission's Department of Environmental Protection stipulates that the use of wet smelting technology to treat used lithium-ion batteries is required, requiring nickel and cobalt. The comprehensive recovery rate of manganese should not be lower than 98%. "For the processing technology of lithium-ion batteries, China has always had research by university research teams and has cooperated with the United States." Wang Fang said.

On January 8th, the Ministry of Industry and Information Technology issued the “Interim Measures for the Administration of the Regulations on the Comprehensive Utilization of Waste Electrical power battery Comprehensive Utilization of New Energy Vehicles (Consultation Draft)”, and proposed to implement dynamic management of the new energy vehicle waste power battery comprehensive utilization enterprises, and entrust relevant professional organizations to assist Do a good job in announcement management.

Hu Shuqing, chief expert and researcher-level senior engineer of China Electronics Technology Group Co., Ltd., said that lithium-ion batteries with lithium iron phosphate, lithium manganate and low-cobalt ternary materials are positive active materials. high. The recycling of these used batteries must be promulgated by the state in order to successfully realize the closed loop of the industry. At present, China has introduced some policies and standards, such as the classification of waste batteries, storage and transportation regulations, solid waste and hazardous waste pollution prevention and control technology policies, but not enough.

“The work of recycling and reusing lithium-ion batteries should be laid out as soon as possible.” Wang Binggang, head of the national 863 energy-saving and new-energy vehicle project supervision consulting expert group, said that to establish a power battery recycling system, it is necessary to improve the standardization of batteries, establish a code traceability system, and implement Strict reward and punishment measures and qualification management for recycling companies.

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