Expert: lithium battery is not terrible but quite durable

Widely spread network of questions about lithium battery also include: toxic issue, short cycle life, explosion issue, harsh conditions of usage; cannot be recycled, great environmental pressure... But are these the truth? The editor continues to interview a number of industry experts to explore the truth.

Lithium batteries are highly toxic dangerous goods?

Response: lithium battery does not contain toxic substances, far less than the impact of lead-acid battery

"There is a conceptual difference between a lithium-ion battery and a lithium battery." Wang fang, a senior engineer and chief expert in the field of power batteries at the China automotive technology research center, and general secretary of the battery testing and application technology alliance, said lithium batteries usually refer to batteries with a negative electrode made of lithium metal or lithium alloy and using non-hydro-electric solutions. Lithium ion battery refers to rechargeable secondary battery, the negative electrode does not use lithium metal, rely on lithium ions to move between the positive and negative poles to work. However, in daily life, people used to lithium ion battery referred to as lithium battery or lithium battery.

It is understood that the new energy vehicles (including pure electric vehicles and plug-in hybrid electric vehicles) promoted in China at present mostly use lithium ion batteries, of which lithium iron phosphate accounts for 80% to 90%. Ternary lithium batteries have also been widely used in passenger vehicles.

Wang fang refuted the claim that lithium batteries are "extremely toxic and dangerous" in the articles posted on the Internet, saying that compared with traditional batteries such as lead-acid, nickel-chromium and nickel-metal hydride, lithium batteries do not produce any toxic and harmful heavy metal elements and substances such as lead, mercury and cadmium, and are relatively less polluted. And the electrolyte is organic solvent and lithium salt, mostly non-toxic or low toxic; However, the decomposition or hydrolysis products of lithium batteries are hydrofluoric acid and other fluorinated compounds, which are corrosive and toxic.

As for "lithium battery is extremely toxic", Liu Haojie, a senior engineer at the 18th research institute of China electronics science and technology group, said that lithium ion battery itself does not contain highly toxic substances, and the carbon in the negative electrode and metal oxide in the positive electrode are basically non-toxic. Because the lithium ion battery is a sealed system, normal use will not be exposed to these substances. "In any case, the impact is much smaller than that of the most widely used lead-acid batteries."

Lithium battery life is short, harsh service conditions?

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

How long is the life of lithium battery? Will shallow charging and discharge or over charging and discharge affect the safety and service life of the battery?

"There are many factors that determine the service life of power lithium-ion batteries, including the characteristics of the system itself, as well as the manufacturing process and operating conditions. Excellent battery system, coupled with scientific system management, can achieve a very long service life. Wang fang said, according to the capacity attenuation to 80% as a cut-off condition, according to 100% of the discharge depth test, the current power battery life can basically reach 2000 cycles.

"Over-charge and over-discharge refers to the battery in the process of charging and discharging voltage over or below the cut-off voltage, the battery performance and life will bring harm. But the BMS battery management system in the battery limits and protects the battery, limiting charging at low temperatures and recharging at the right temperature, Ms. Wang said. Wang fang said that in order to ensure the safety of lithium ion battery, from the battery monomer, module to the battery system has a series of safety protection design, to prevent the battery overcharge to let off temperature, in the event of abnormal alarm and protection.

The article mentioned: media reports, "Tianjin 18 proved that lithium battery in high temperature and high pressure, puncture impact, overcharge and discharge in almost all projects occurred in the combustion and explosion.

In response, liu yanlong, secretary general of China chemical and physical power industry association, said that at the end of May 2014, the 18th institute of China electronic science and technology group gave a special interview to the media, but the burning and explosion of the battery in the program was caused by the abuse experiment after the protection circuit was removed according to the recording requirements of the program. The main purpose of this experiment is to let the majority of users to understand the protection measures of lithium three battery in the abuse of conditions may be dangerous.

"The safety of lithium-ion batteries is theoretically controllable, and safety issues are often caused by product defects and abuse." "Liu Yanlong said. "But the safety of single batteries, modules and systems is not enough to guarantee the absolute safety of electric vehicles with lithium batteries." Ningde times new energy technology co., LTD. (CATL) chairman li ping introduced, the current top matching Model -- S used 7104 Panasonic ternary lithium batteries, in the battery safety protection to do enough work, including the setting of sensors, battery control system control, a large number of high-strength aluminum alloy materials such as collision protection. In the case of these safety design, the probability of safety accidents or reached one in 10,000.

Researcher at the institute of China electronics technology group 18 level senior engineer Wang Qinghua also pointed out that at present the electric car battery products on the market the good and bad are intermingled, some manufacturers of battery problems of poor consistency, and the effect of management system play a little, a monomer problems can produce certain effect to the whole life of the battery pack. In this regard, Wang Qinghua suggested that the government should improve the corresponding test verification standards and strengthen the management, supervision and testing of the electric vehicle market.

Uncontrollable pollution of used lithium batteries?

Response: due to the relatively small environmental risk, lithium battery has not been included in the hazardous waste management, but should be laid out as early as possible recycling system

Is there a mandatory recycling policy for lithium batteries? As mentioned in the article posted on the Internet, waste lithium batteries will cause great environmental pressure? Wang fang said that at the present stage, the environmental protection department included waste batteries for hazardous waste management, including waste cadmium nickel batteries and waste lead-acid batteries. Disposable batteries, lithium ion batteries and nickel metal hydride batteries are not included in hazardous waste management due to their relatively small environmental risks.

However, when the waste lithium ion battery enters the environment, the electrode material and electrolyte react with other substances in the environment, such as hydrolysis and oxidation, which may cause heavy metal ion pollution such as nickel, cobalt and manganese, fluorine pollution and some organic pollution. So is the pollution manageable?

Wang fang said that for the disposal of lithium ion batteries, the policy on recycling and utilization of electric vehicle power batteries (2015 edition) drafted by the environmental resources department of the national development and reform commission encourages the use of wet smelting technology to dispose of waste lithium ion batteries, and requires that the comprehensive recovery rate of nickel, cobalt and manganese should not be less than 98%. "For the treatment technology of lithium ion battery, our country has always had a university research team to carry out research, and carried out cooperation and exchange with the United States. Wang fang said.

The ministry of industry and information technology on January 8 issued the "interim measures for announcement management of new energy vehicle waste power battery comprehensive utilization industry standard (draft for soliciting opinions)", proposing to implement dynamic management of new energy vehicle waste power battery comprehensive utilization enterprises, entrusting relevant professional institutions to assist in the announcement management related work.

Hu shuqing, chief expert and senior engineer at the level of researcher of China electronics science and technology corporation, said that for lithium ion batteries with positive active materials such as lithium iron phosphate, lithium manganate and low-cobalt ternary materials, the recycling business value is low and the enterprise interest is not high. The recycling of these waste batteries must be carried out by the state policy, in order to successfully achieve industrial closed-loop. At present, China has issued some policies and standards, such as the classification of waste batteries, storage and transportation specifications, solid waste and hazardous waste pollution prevention and control technology policies, but not enough.

"Lithium ion battery recycling work, to layout as soon as possible. Wang binggang, head of the national 863 energy conservation and new energy vehicle project supervision advisory group of experts, said that the establishment of the power battery recycling system, the need to improve the battery standardization, the establishment of a code traceability system, the implementation of strict incentives and punishment measures, as well as the renewable enterprises for qualification management.

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