Some misunderstanding about lithium-ion batteries

On the "lithium battery toxic theory", Liuhaojie, senior engineer of the 18th Institute of China Electronic Technology Group, said that lithium ion batteries themselves do not contain highly toxic substances, negative carbon and positive metal oxides are basically non-toxic. Since lithium-ion batteries are sealed, these substances will not be exposed to normal use. "In any case, the impact is much smaller than the most widely used lead-acid batteries. "

Lithium battery short life, harsh conditions for use?

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

How long is lithium current electric life? Does shallow and overcharged placement have an impact on battery safety and life?

"There are many factors that determine the service life of powered lithium-ion batteries, including the characteristics of the system itself, as well as manufacturing processes and operating conditions. A high quality battery system, coupled with 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 power cell life can basically reach 2000 cycles.

"Overcharge over discharge means that the voltage of the battery in the process of charging and discharging exceeds or is lower than the specified cut-off voltage, which will cause harm to the battery performance and life. "But the BMS battery management system in the battery will be limited and protected. At low temperatures, the battery will be limited to charging and recharging when heated to a suitable temperature," Wang said. 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 the battery from overcharging and letting go of temperature, and timely warning and protection in the event of an anomaly, Wang said.

The net mentioned: There have been media reports that "Tianjin 18 has proved that lithium batteries have burned and exploded in almost all projects such as high temperature and high pressure, puncture impact, and overcharging."

In response, Liuyanlong, Secretary General of the China Chemical and Physical Power Industry Association, said that at the end of May 2014, the 18th Institute of China Electronic Technology Group was interviewed by the media. However, the phenomenon of burning explosions in the batteries in the program was based on the recording requirements of the program. After the protection circuit was dismantled, an abuse experiment was conducted. The main purpose of this experiment is to enable users to understand the dangers that may occur under the conditions of misuse of unprotected lithium ternary batteries.

"Lithium-ion battery safety is theoretically controllable, and safety problems are mostly caused by product defects and misuse. " said Liuyanlong. "But the safety of battery cells, modules and systems alone is not enough to guarantee the absolute safety of an electric car equipped with a lithium battery. Li Ping, chairman of the New Energy Technology Co., Ltd.(CATL) in the Ningde era, said that the current Model-S equipped with 7,104 Panasonic Sanyuan lithium batteries has done enough to protect battery safety. Including the installation of sensors, controlled by battery control systems, the use of high-strength aluminum alloy and other materials collision protection. In the case of these safety designs, the probability of safety accidents still reaches one in 10,000.

Wangqinghua, a senior engineer at the researcher level of the 18th Institute of China Electronic Technology Group, also pointed out that the current products in the electric car battery market are uneven, and some batteries produced by manufacturers have problems of poor consistency, and the effectiveness of the management system is not great. A single monomer problem will have a certain impact on the overall life of the battery. In this regard, Wangqinghua suggested that the government improve the corresponding test verification standards and strengthen the management and monitoring of the electric vehicle market.

Can not waste lithium battery pollution be controlled?

Response: Lithium batteries are not yet part of hazardous waste management due to relatively small environmental risks, but recycling systems should be deployed as soon as possible

Is there a mandatory recycling policy for lithium batteries? Is it possible, as the article said, that used lithium batteries can cause enormous environmental pressure? Waste batteries that are now being managed by the Environmental Protection department as hazardous waste include cadmium nickel batteries and lead-acid batteries, Wang said. For disposable batteries, lithium-ion batteries, nickel-metal hydride batteries, etc., because of their relatively small environmental risks, they are not included in the management of hazardous waste.

However, waste lithium ion batteries enter the environment and are hydrolyzed and oxidized by electrode materials, electrolytes, and other substances in the environment. This may cause heavy metal ion pollution such as nickel, cobalt, and manganese, fluorine pollution, and some organic matter pollution. So, is this pollution manageable?

Wang said that for the treatment of lithium-ion batteries, the National Development and Reform Commission's Ministry of Finance drafted the "Policy on the Recycling of Electric Vehicle Power Battery(2015 Edition)" to encourage the use of wet smelting technology to treat used lithium ion batteries. The comprehensive recovery rate for nickel, cobalt and manganese is required to be no less than 98 per cent. "For the treatment technology of lithium-ion batteries, China has always had a university research team to conduct research and carry out cooperation and exchanges with the United States. " said Wang Fang.

On January 8, the Ministry of Industry and Information Technology issued the "Interim Measures for the Administration of the Industry Specification for the Comprehensive Utilization of New Energy Vehicle Power Battery"(Draft for Consultation), which intends to implement dynamic management of the comprehensive utilization of new energy vehicle power battery enterprises and entrust relevant professional institutions to be responsible for assisting in the announcement management.

Lithium-ion batteries with lithium iron phosphate, lithium manganate and low cobalt content as active materials are of low commercial value due to low recycling interest, said Hushuqing, chief expert and senior engineer at the researcher level at China National Electronics Technology Corporation. The recycling of these used batteries must be issued by the state to successfully achieve industrial closed-loop. At present, China has promulgated some policies and standards, such as the classification of used batteries, storage and transportation codes, and technical policies for the prevention and control of pollution from solid waste and hazardous waste.

"The recycling and reuse of lithium ion batteries should be arranged as soon as possible. "The establishment of a power battery recycling system requires the standardization of batteries, the establishment of a coding and tracing system, the implementation of strict rewards and penalties, and the qualification management of recycling enterprises," said Wangbinggang, head of the National 863 Energy Conservation and New Energy Vehicle Project Supervision Advisory Expert Group.

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