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Current Status And Development Trend Of Lithium Ion Energy Storage Battery
- Jun 19, 2018 -


We know that lithium-ion batteries are energy storage technologies. This year, more attention has been paid to energy storage. Our energy storage power station is being built continuously. In addition to the energy storage power station, the lithium ion battery is built more. The centralized test has reached 100 megawatts, whether it is the household or the so-called centralized test.


Why are these two technologies developing faster? First, large-scale, and two, low cost and distributed. Now the two are starting to compete. Lithium ion batteries are particularly important. Other energy storage technologies, including liquid batteries, are seventy percent and lithium ion batteries are about ninety percent.


Batteries are the most efficient way of storing energy. There are many kinds of batteries. We are talking about energy storage batteries. Lead-acid and lithium ions are used in energy storage. Distributed batteries store more energy than lead-acid and lithium ions. The difference between lead acid and lithium ion is that lithium ion develops faster. Lithium ion is characterized by good life expectancy in the wide charge discharge range. The above image shows that the long term storage capacity of lithium ion does not reach 100% of DOD. In the long run, energy storage is usually 75%DOD. The life of 75%DOD is very long. If the lead-acid battery has to reach the same life expectancy, it can not exceed 30%, and the actual usable capacity is low. You can increase the depth of lead-acid batteries to 80%, a little stronger than you, but your life is going down. I am considering the same life expectancy, and at the depth of discharge, the cost of lithium ion batteries per watt hour is lower than that of lead-acid batteries. Not to mention other advantages, this is the fastest development of today's energy storage lithium ion batteries.


Batteries are made of different materials, and 70% of the cost comes from materials, or even more than one point. The anode and cathode materials of the lithium ion battery have many kinds of materials. In terms of electric vehicles, we know that there are iron lithium. There are many materials that can make battery materials. Many lithium compounds and lithium iron phosphate can be used as cathode materials.  Many of them can react with lithium, which can be used as anode materials, so they have graphite materials, carbon materials, alloy materials and so on.


The most important thing about energy storage is safety. Household energy storage is installed in the family. Large energy storage can be built to 100 MW or even gigawatts. It has a higher efficiency and a faster response. There are many flammable materials in the battery. Adding negative electrodes will become a lively material. For firewood to burn, we need matches. Matches are highly oxidizing. The stronger the oxidability, the more normal the mobile phone battery is. No matter what happens, the electricity will turn into a high price oxide and turn into a match for ignition. Our batteries are very reliable. We have to prevent all kinds of accidents. The accident is caused by overheated batteries. Our cathode material has a strong oxidizing type after charging, and it starts to react with negative materials, including breakage, fire and explosion. This is very dangerous.


At present, we can not choose negative materials. Lithium carbonate is too expensive. Now 99% of the battery is used as a carbon material. When negative materials and electrolytes can not be changed, when it comes to electrolytes, there will be solid electrolytes after 10 years. At this time cathode materials become very important. So many positive materials, we give priority to the most safe cathode materials, each has its own characteristics. Once heated, the charging cathode material and electrolyte will react. Tesla's car is most prone to react and hit a fire once. After the NCA is charged, the oxidation is the strongest.


What material is the most safe? Lithium phosphate, the only material, heating after the electric reaction, the temperature will drop down, the rest can not, the other material is the process of acceleration. Today, as the main material, lithium iron phosphate is grateful to the two old people. In 1997, the professor proposed an iron phosphate material. In 1999, Professor M.Armand proposed nanocrystallization, from insulator to electronic conductivity, to meet the characteristics of battery demand. In October this year, the United States hosted a special meeting to thank them, and we will all take part in it.


This conference is mainly a tribute to MichelArmand. Many people here are making lithium-ion batteries. Many people do not know how lithium ion batteries came. In 1971, lithium crystals were made in the US market. In 1972, the concept was formally published at international conferences, which was later made of lithium graphite compounds. It also made an important contribution to solid state batteries. When making doctoral dissertations in 1978, it talked about polymer solid electrolytes. In 1980, the concept of "rocking chair battery" was put forward. At the same time, the development of Hydro-Quebec lithium polymer battery technology in Canada was led, and more than 4000 cars have been operated in Paris. In 1999, the 196th international electrochemical conference held in Hawaii, United States, reported that carbon coating could solve the problem of conductivity of lithium iron phosphate cathode material. The industrialization of carbon coated lithium iron phosphate was realized by establishing Phostech. Solid state batteries can be used, but today's solid state batteries are not good enough, and there is a gap between economic performance and lithium ion batteries. The economic price should be 10 years later.  The back is his contribution to the lithium iron phosphate.


Not only do we need to choose stable lithium iron phosphate material, but the lithium iron phosphate car also exploded and caught fire and hit in Shenzhen. I think the material is on the one hand, and the battery structure is also very important. This is Boeing 787 battery. How many times did the plane fire? It cost a lot of money. It used a kind of material at that time, and the combination of the two led to this problem. For such a big accident, let's leave no details here. Hundreds of thousands of dollars were paid for the car accident, and the case was compensated for hundreds of thousands of dollars.


10 years ago, we tested at the European law and electrical testing center, over 6000 lives, 100%DOD, and 80%. Not only did we do well in the lab, but we applied it in industry and made more than 2000 shared rental cars. In 2010, there were 73 cars, more than 900 cars in 2011, and more than 1300 cars in 2011. The shortest has been used for more than 5 years, and the longest took nearly 8 years. More than 2000 times, the car to do a sampling test, now the battery has the lowest capacity of 73%, prove that lithium iron phosphate battery can meet the long time application. People are more confident in energy storage.


In order to improve the manufacturing technology, Yang also took part in this matter. Where the Academy of Sciences is not far from here, we set up a public platform in Nansha to allow research institutes to start research and technology from lamination.


Last year, we made a modified lithium iron phosphate battery. Now most of them are used for energy storage, because electric vehicles need higher energy density, and now they exceed 100Ah. This is the result of the electrical test. The life expectancy at room temperature and 45 degrees is very good, which is necessary for long-term energy storage. The key to solve this problem is the difference in design. Most of the batteries are positive and negative, and the battery has different designs. The positive electrode is in the same set of negative electrodes, so wide, the fever is located in the part of the ear. The negative electrode has good conductivity and is coated with carbon material. The positive electrode uses the whole ear, the heat can be evenly distributed and the work of high current. We use infrared camera to see the heat distribution is very good. Not only the temperature is good, but also the heat conduction is very good and the heat conduction is easy. We use tight structure to store energy, and the heat at the bottom can be easily transmitted. It is solid, not blown by fans. The heat transfer of gas is the slowest. The heat transfer of liquid is faster than that of gas, and the heat conduction of metal solid is the fastest. If the energy storage system uses a small fan, there is no fan to turn around for more than ten years. So solid heat conduction is very good, and it can be used as a dense energy storage system. The energy density of three yuan is high. What you say is energy. I don't think that's right. I can make soft bags into 200 watts, and 250-260 kilograms per kilogram. From the perspective of battery pack, there is not much difference between iron lithium and three yuan. Talk about the energy density, how many hours a liter. The same size, container energy storage cabinet, if using iron lithium, can be more than three yuan 40-50% energy. The energy density of lithium iron phosphate is 40-50% higher than that of three yuan.


This is what I asked the French electric staff to see. A 40 foot cabinet can be installed with three yuan battery for 2.5 MW, including PCS function. The density of iron lithium battery is much better than that of other batteries. The energy storage system will have more and more due.


One of the application scenarios: a new energy dissipation solution


Because the variability of wind and solar energy is difficult to predict, the system inertia can not be provided, which makes the power grid system more easily touches the upper limit of the power frequency fluctuation, and makes the reliability of the power system weak. The energy storage system can help the renewable energy station to improve the ability to reduce the energy consumption. It also plays an important role in cutting peak and filling the valley and improving the power plant output, while effectively solving the increasingly serious "abandonment of the light" problem.


Significance: help the new energy power plant to adjust the peak, reduce the power grid system under the impact of new energy grid, reduce the pressure of the power grid, absorb the harmonics generated by the photovoltaic and wind power, improve the power quality of the new energy generation, and smooth the intermittent fluctuation.


Income point: to improve the capacity of new energy dissipation, to absorb the electric quantity of abandoned wind and abandon the wind, to change the time to surf the Internet, to achieve the growth of income, to smooth the power output, to reduce the pressure of the power grid, to improve the accuracy of the power generation forecast and to relieve the pressure of the expansion of the power grid.


Now the reserve cost of lithium ion battery is about 0.3 yuan, and many companies are making money with it.


Two of application scenarios: user side customization solutions


According to different types of needs, we provide a set of customized energy storage solutions for users. Through energy storage, peak load and valley filling can be realized, the power consumption plan can be optimized, the demand side response can be made in response to the power grid, and the backup power supply can also be used in emergency. The user side energy storage has broad prospects for development, which is widely applied to all kinds of applications, from small and medium sized industrial and commercial users to power users and electric power generation.


High quality and high quality industry.


Significance: to improve energy stability and utilization for new energy users; make greater use of peak and valley difference; reduce power grid dependence, respond to peak time limit electricity; demand side response, reduce power grid pressure; electric energy management, improve power quality, can meet special load power quality demand; can be used as backup power, and ensure fast switching, response, response, response Emergency.


Income point: peak valley difference Arbitrage: Valley charge, peak time power consumption; reduce the basic electricity cost: reduce peak load, reduce the basic electricity fee according to the maximum measurement; demand side response subsidy: according to different local policies, users can reduce the load according to response; power obtain subsidies; improve the quality of electricity, and reduce the loss of precision equipment loss of some users. It is consumed.


Application scenario three: a microgrid energy storage solution


Microgrid is a small power distribution system, which consists of distributed power, energy storage device, energy conversion device, load, monitoring and protection device. It is an autonomous system that can realize self control, protection and management. As a complete power system, it can rely on its own control and management to achieve power balance control, system operation optimization, fault detection and protection, power quality control and other functions.