Frequent electric car burning accident? Solid state lithium battery or can be avoided

In December 2018 06, 07:24 source: Science Daily
Original title: frequent electric car burning accident? Solid state lithium battery or can be avoided

Liquid lithium battery, by scientists known as the "rocking chair battery", positive and negative poles at both ends of the middle rocking chair battery, electrolyte (liquid). The lithium ion as the outstanding athletes in the positive and negative poles back and forth between the run, the charge and discharge process in the process of movement to complete the battery.

However, this seemingly interesting structure but there are hidden dangers. According to incomplete statistics, the first half of this year there have been 10 electric car burning accident. A fire unit summed up the occurrence of new energy vehicles, the most common manifestations of the burning scene for charging in the process of combustion, in addition, the battery will also produce combustion in driving or stopping process.

Not long ago, the second session held in Beijing to the direction of storage battery technology development seminar, the experts on the current battery problems are discussed, that the solid-state batteries is relatively more ideal choice.

High safety, inheritable liquid lithium battery "status"

Why would frequent liquid lithium battery explosion, expert analysis, the reason is that traditional lithium batteries work possible lithium dendrite at high current, so as to cause a short circuit failure through the diaphragm; the electrolyte is organic liquid, under high temperature will aggravate the side reaction, oxidation and decomposition, gas, combustion tendency.

In recent years, the academia, the industry that uses solid-state batteries in security relative protection as the liquid lithium battery can inherit the "status of the political arena".

The energy storage spring has come, the storage industry began to sprout and flowering, in all kinds of energy storage technology, energy storage battery the most attention, is the fastest growing energy storage technology. All solid state lithium ion battery is a chemical power scale energy storage ideal." Study on electrical storage technology research group China Academy of Sciences Professor Chen Yongchong said.

Experts believe that using solid electrolyte instead of conventional organic liquid electrolyte all solid state lithium ion battery, the battery is expected to solve the security problem fundamentally, is the ideal chemical power of electric vehicles and large-scale energy storage.

Beijing Institute of Technology, National Engineering Lab for electric vehicles, China Electrotechnical Society member Specialized Committee said Sun Qing, compared with the traditional lithium battery, lithium battery electrolyte is between solid solid state, there are certain advantages in theory.

The solid state lithium battery using lithium compound, sodium glass is made of conductive material, to replace the previous electrolyte of lithium battery, greatly enhance the energy density of lithium batteries. Using solid electrolyte, can prevent the battery from the combustion of some components.

The experts, the density and structure of solid state lithium battery allows more charged ions gathered in the end, conduction more current, and enhance the capacity of the battery. Therefore, in the same power, solid state battery volume will be smaller. Also, because there is no electrolyte solid state battery, storage will become easier, used in automotive and other large equipment, do not need any additional cooling tube, electronic control, not only cost savings, but also effectively reduce weight.

The development is still on the road, some key problems to be a breakthrough

The solid electrolyte of lithium battery is introduced, in order to break through the limitations of existing organic electrolyte, enhance the energy density of the battery, power, temperature range and safety. The experts, really achieve these goals, still need to first solve the existing problems with the electrolyte material itself and electrode interface.

Deputy researcher of Shanghai Silicate Research Institute Chinese Jin Jun said that in recent years they mainly developed by Laboratory of solid electrolyte lithium sulfur battery system. Lithium metal modified by solid electrolyte, the cycle stability of the battery can be enhanced. They also proposed a dual electrolyte lithium sulfur battery concept, using a solid electrolyte having lithium ion conductivity of LAGP system, in between the positive and negative poles by a small amount of liquid electrolyte wettability, the test results can be seen, the first discharge capacity can reach more than the theoretical capacity of 80%, especially in the aspect of the charge discharge efficiency, basically close to 100% no, the shuttle effect problems of liquid lithium sulfur battery. In order to further solve the security problems of the battery, they made the interface gel, to ensure that there is no electrolyte flow dynamics, modified by polymer, can also buffer volume effect during the cycle.

College of materials Tsinghua University associate professor Li Liangliang team is developing a solid oxide electrolyte and solid state lithium battery prototype, using three yuan cathode, solid electrolyte film and graphite as cathode load, battery energy density, good safety, maintain the capacity of 81% thousands of cycles.

Hefei Boao Guoxing Energy Technology Co. Ltd. Dr. Zheng Mingsen pointed out that at present the research and development of laminated large capacity solid state polymer lithium ion battery, relatively simple structure, few nodes do not need management system, in the assembly of battery only in series rather than in parallel. Using some solid electrolyte instead of liquid electrolyte traditional, can solve the battery leakage and collision after combustion, improving the safety of the battery.

Of course, the development of solid-state batteries are still on the way, there are still some key problems to be a breakthrough. Experts said that the solid battery used in the field of energy storage should be considered to long life, safety and other factors. In addition, still need the volume effect, solve the long-term cycle stability and interfacial compatibility problems.

(commissioning editor Yang Sengyu and Hu Yigong)

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