How far is it from realizing the safety and industrialization of lithium battery?

Safety is always lithium battery head of a sword, including lithium electricity on the industrial chain companies, research institutions and industry to all parties have been spare no effort to solve the problem of the "problem". Among them, the research production of solid-state lithium battery is the industry put forward a new idea and new method.

Chinese academy of engineering academician Chen said: "in 2014 I was put forward for 5 years (solid-state lithium battery) industrialization, solid-state batteries is that we achieve the lead of the rare opportunity, 40 years ago began to study in our country, we have."

Solid-state lithium battery is still in the development stage at present, has been part of domestic enterprises in technical research. All solid state lithium battery research and development process in what stage? How far is it from industrialization? This paper will help readers know more clearly all solid state lithium battery and its industrialization.

The technology principle

All solid state lithium battery, the battery units, including anode, electrolyte are all adopt the solid material of lithium secondary battery, developed from the 1950 s, its working principle and the liquid electrolyte lithium ion batteries principle of the same.

At present, according to the electrolyte, solid-state lithium battery mainly include two categories: one is composed of organic polymer electrolyte solid-state lithium-ion batteries, called solid-state lithium polymer battery; Second is inorganic solid electrolyte of lithium ion battery, called inorganic solid-state lithium batteries, there are mainly the oxide and sulfide.

On the structure, all solid state more simple than traditional lithium-ion batteries, lithium-ion batteries solid electrolyte in addition to conducting lithium ion, also act as the role of the diaphragm. Therefore, in all solid state lithium battery, the electrolyte, electrolyte salt, diaphragm and UF agent don't need to use such as poly (vinylidene fluoride, greatly simplify the build steps of battery.

All solid state lithium polymer battery has the advantage of high safety, not only can be prepared into various shapes, and through the preparation is relatively easy to roll to roll mode; Inorganic solid-state lithium battery using inorganic solid electrolyte materials, has high mechanical strength, do not contain flammable, volatile components, there is no leakage, good temperature resistance.

At the same time, easier to achieve large-scale preparation of inorganic materials to meet the needs of the large size batteries, can also be prepared into a thin film, the lithium battery miniaturization, assembly of inorganic material film inorganic solid electrolyte of lithium battery has long storage life and cycle performance.

Hinder the industrialization problem?

Jiangsu Qing Tao energy technology co., LTD. (hereinafter referred to as the "energy" qing ceramics), chief technology officer, says Dr. Li Zheng solid-state batteries to realize industrialization at present there are mainly two problems: one is the solid electrolyte the ionic conductivity at room temperature is not high. The second is a solid electrolyte interface between is negative impedance is larger.

Currently used polymers, oxide, sulfide solid electrolyte are these problems. Specifically, the polymers and heat-resistant performance is not enough, a little bit good interface problem, but poor electrochemical window narrower, stability, ion conductivity is low; Oxide interface resistance is bigger, ionic conductivity and low; Sulfide in higher ionic conductivity, but poor interface ion transport properties, and the stability of the material itself is not good.

Had earlier media reports, the French Bollore have put 3500 urban rental car in London, England. According to this batch of rental cars are for the use of solid-state lithium battery electric vehicle, the chemical system for Li/PEO/LFP batteries, battery pack up to 300 kg weight, energy density in 100 wh/kg, and after a 1300 - cycle, the water capacity of up to 80%.

Solid electrolyte industry technical experts, the narrow range of applicable temperature and the Bollore company electric cars need heating components, battery heated to 80 degrees Celsius to activate, temperature, electrical conductivity.

Directly start the engine with ordinary cars can set off, the battery temperature rising this process not only trouble, and will consume energy, which can lead to a significant reduction in the effective energy density of the overall battery Pack. At the same time as a result of the solid polymer battery power performance is poor, so in actual use, need and high-power super capacitor.

More obvious defects is based on the PEO polymer solid electrolyte electrochemical stability window narrower, generally in the following 4 v, the positive material selection of the corresponding only LFP, its overall energy density makes it difficult for them to achieve 300 wh/kg.

Enterprises to actively layout

Although solid-state batteries using solid electrolyte also faces many problems, but this does not affect the industrialization of the confidence of the solid-state batteries. And for one of the difficulties, many companies open technology research and development mode.

The sulphide solid electrolyte is important development direction of Ningde era. Sulfur solid-state batteries have the positive and negative interface problems of interface reaction. For the anode interface can solve the anode coating modification methods, and the cathode interface can be in lithium metal surface to form a stable layer of buffer layer.

Practice, sulfide and ionic conductivity of contact problems, poor stability of air and water, the water would not only after release poisonous hydrogen sulfide gas, and the smell is very smelly, if the problems in the process of using car, people can't afford.

Ningde era of new energy technology co., LTD. Chengdu, said Dr. Liang Ningde era by hot-pressing way to improve the interface contact to increase the overall ionic conductivity of battery system, and studies of sulfide material was improved, improve the stability of it, towards the industrialization further.

But manufacturing is a big challenge, the production process, process method and the traditional production method of lithium ion battery was completely different, ningde age has make a series of materials research and development, in the way of the industrialization of solid-state batteries positive layout.

"All roads lead to Rome", in the development of all solid state lithium battery electrolyte path choice, every company will have their own choice. Li Zheng said, the technical route of clear Tao energy is made of polymer and the oxide compound material, although the part can avoid the common problems of solid polymer electrolyte, but still need to improve, the corresponding is negative also need to change.

The industry there is a consensus that industrialization is still too early to talk about solid-state lithium battery now, because of its form a complete set of materials, equipment, process is not yet mature, even no production equipment. While Li Zheng revealed that at the beginning of the Qing Tao established energy is to produce the purpose of all solid state lithium batteries, form a complete set of equipment company name check has been completed, is in the industrial and commercial registration.

Research high production of lithium electricity institute (GGII) analysts, solid-state batteries energy density of the theoretical value is very high, but the current engineering ability is not enough, the whole package in 100-200 wh/kg, also has the very big promotion space. In order to realize the large-scale industrialization of solid-state batteries, is critical technological breakthroughs, and material, process, equipment requires corresponding ascension.

The page contains the contents of the machine translation.