Why electric buses are not equipped with ternary lithium?

Director-general of the department of ministry of machinery industry a picture of wood in 2016 China electric car c) said on the BBS, suspend the ternary lithium battery bus on the catalog of new energy automobile application recommended models, it expressed concern about the safety of power battery to state.In fact, in this year to the new directory on January 14 dated department, there is no assembly batteries ternary material coach products.

Told them a picture of wood, the ternary lithium battery high specific energy, cycle performance is good, is one of the important developing direction of the future lithium battery, but in this field in China started late, the products are used in passenger security development and validation is not enough.The ministry is considering further improve the new energy automotive product safety technical threshold, organize the ternary lithium battery bus models in the current safety standards under the system of risk assessment.He made it clear that before the review completed, suspended ternary lithium battery buses on the catalog of new energy automobile application recommended models.

Three yuan s high temperature material flammable

The security risks of ternary material is larger.Researcher at the institute of physics of Chinese academy of sciences, said huang summary of accident experience, aluminum nickel and cobalt ternary material 18650 cell in 180 ℃ above will appear from heating, difficult to control, after a fire and lithium iron phosphate material can only be seen to be over 250 ℃ heat emission phenomenon, security is relatively high.

From material properties, two materials arrived at a certain temperature decomposition, can occur in a ternary lithium material probably occur at about 200 ℃ decomposition, lithium iron phosphate decompose in 700 ~ 800 ℃.And, ternary lithium materials chemistry more intense, can release oxygen, under the effect of high temperature rapid combustion, electrolyte in a chain reaction.Lithium iron phosphate decompose when won't release oxygen, burning less severe.Therefore, the onlyLithium ion batteriesThe positive in terms of material properties, of the ternary lithium materials more easily than the lithium iron phosphate material fire or accident.

S battery capacity big lead to poor heat dissipation

Besides three yuan material safety risk, passenger car battery capacity is bigger, also increased the degree of danger of ternary battery.Huang said the battery safety and is inversely proportional to the energy stored in the battery, which can release the energy, the greater the security risks of its existence, pure electric car battery capacity is usually dozens of KWH, pure electric bus several hundred KWH battery capacity, with the increase of battery capacity, battery volume is increasing, its thermal performance is poor, the possibility of accidents.

Huang told reporters that the lithium ion power battery, battery must improve its safety performance, the greater the monomer battery, has the higher requirements for the safety of the indicators.In addition, the safety of the battery system is not only determined by the monomer battery.China's chemical and physical power industry association secretary-general yan-long liu thinks, the electric car battery, charging method of group technology, using method and maintenance method, the reliability of protection system, the effectiveness of the communication protocol, etc will affect the safety of the battery pack.

S lack of evaluation system

It is because of the lack of corresponding domestic evaluation system, it is difficult to evaluate three yuan cell system the security situation.Monomer battery group according to the vehicle battery pack is designed using condition, by strengthening the whole production process monitoring, can effectively promote the ternary cell system security, but in the end, or not need to identify corresponding evaluation system, through security yan-long liu told reporters, "domestic lack of the corresponding evaluation system."

Ministry of science and technology electric car major s&t special Wang Binggang distinguished experts and yan-long liu to see eye to eye.Wang Binggang thinks, battery material choice and can not fundamentally solve the problem of the battery safety, should be strict battery product quality requirements and regulatory measures., Wang Binggang two Suggestions, one is the need for battery module and system setting clear safety assessment indicator;The second is the new energy bus to strict monitoring, monitoring content and responsibilities.

Chinaspecial lithium electricity (Luoyang) co., LTD. Marketing Department minister RuanYiLiang thinks, passenger train route, the environment is relatively fixed, battery is not a bus the most focus of attention, should adhere to the higher thermal stability and security more secure route of lithium iron phosphate.Data show that at present in our country, the production of pure electric passenger cars, use lithium iron phosphate power battery passenger cars accounted for sixty percent of all new energy bus market share, the ternary material power battery to occupy the market share of thirty percent.Lithium iron phosphate batteries now is still the mainstream direction in the field of electric buses, at the same time also is the optimal choice.

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