Figure 1 The use of the energy storage device in the smart grid is due to the driving of the related industries such as electric vehicles, the scale of the lithium-ion battery industry quickly expands, the price is rapid, and the application of lithium ion battery as a distributed energy storage system is gradually increased.. As of the end of 2018, my country’s accumulated electric chemical energy storage project has 1072.
7mW, of which the lithium-ion battery energy storage project accounts for about 60%.. In the context of building a flexible smart grid, from increasing power grid toughness, adjustability, flexibility, intelligence, independence, reduced coupling, no matter which application, energy storage is effective means one.
From currently selectable energy storage components, lithium-ion batteries are a relatively suitable choice, especially regarding user side energy storage, lithium-ion battery as high energy density, long life, and other advantages, etc.. However, the current user side lithium-ion battery energy storage is slow, whether it is the economic, safety or application of the energy storage system itself, and needs to be broken.
. First, the lithium-ion battery can save money? At present, the user-side lithium-ion battery storage can not be more than many other benefits in addition to the peak of the peak, and the economic return is single..
Peak Filling Valley is more dependent on the regional peak value, Figure 3 shows the domestic peak cereal price difference distribution area. From the perspective of research, Beijing Peak cereal is the largest, more than 1 dollar, so it is the most advantageous application in the peak valley arbitrage application..
Next, it is Tianjin, Shanghai, Jiangsu and Guangdong.. Overall, the first-tier cities and coastal provinces are more active in promoting the price of peak valley, so the user side energy storage will have better economy.
. Figure 3 Splitting Peak Rapid Economic Region Division Figure 4 Comparison of Independent Peak Filler Revenue Characterization Figure 4 shows the peak yield of the energy storage project (the abscissa is KWH investment cost, the ordinate is the full life cycle Rate, different color curves represent peak cereal price differentials). The lithium ion battery model considers the charge and discharge efficiency, depth, and capacity decline.
According to 4,500 cycles, the number of 1500-2000 secondary use cycles is used, and 20% of the residual value is considered in the calculation.. As can be seen from Figure 4, even if this ideal algorithm is adopted, the yield is not very considerable (only when the peak valley difference reaches 0.
7 yuan, the yield will occur). In addition, there is currently a good quality of lithium-ion batteries in the energy storage industry, and the owners and integrators are difficult to make an intuitive judgment on battery performance..
The cycle of lithium-ion batteries on the market is 3000 times to 6000 times (even if the manufacturer promises to cycle, if it is only used for peak-filling, there may be no battery life, the calendar life has also arrived, this same Will reduce battery use efficiency), and no big questions in actual operation. These have added investors’ questions about the economics of lithium-ion battery energy storage projects, which added lithium-ion battery energy storage in user-side applications..
Second, the lithium-ion battery will be safer? The lithium-ion battery is an energy body. It is characterized by high energy density. Therefore, itself has safety risks, the higher the energy density, the greater the security risks.
. At present, the domestic lithium-ion battery energy storage industry basically eliminates the ternary battery. The phosphate ion battery is also considered to be a truth (the energy density of the ternary battery is higher than the lithium iron phosphate ion battery, the safety risks of the ternary battery are also greater than the iron phosphate Lithium Ion Battery).
Figure 5 The explosive safety hazard caused by the high energy density of the battery increases the quality of lithium-ion battery, and it is necessary to reduce battery out of control.. At present, the safety of lithium-ion battery energy is more concentrated in the lithium ion battery itself, but the energy storage system does not only only lithium ion batteries, and other system equipment, protection equipment, etc.
, the safety problem is also worth paying attention.. Current owners and integrators will focus on battery itself, but ignore peripherals and system integration design.
. For example, the survey results of a energy storage accident in Shanxi indicate that the cause of the accident is continuously discharged on the top of the fixed bolt, not the cause of the battery itself..
South Korea summarizes 23 stored system accidents to four aspects: poor electric shock protection system, operational operation environment management is not good, installation negligence, integrated control system management is not good (see Arctic Star Storage Network – Battery does not have a pot! The reason for the accident, South Korea proposed four major improvement measures). These have shown that in addition to selecting the quality of lithium-ion batteries, the safety of their energy storage systems still has a probability of hidden dangers, and it is necessary to ensure the system integration design guarantee for more and more complexing..
Third, whether the lithium-ion battery is applied first from attribute perspective, the current energy storage system applies more to a production unit in the grid.. Regarding the user side energy storage, its characteristics and user-side operation behaviors are close, showing more, broad, quantity, dispersion, etc.
, is a can be arrested and adjusted user-side device. If only mean the meaning of a production unit, then its application constraints will be a lot..
At present, it has been established for the construction, operation, maintenance of lithium-ion battery energy storage system, but due to the emergence of lithium-ion battery energy storage systems, the relevant guidelines and basis needs to be further improved.. For example: national standard “GB51048-2014 Electrochemical energy storage power station design specifications” is important to make energy storage as independent production units, current user-side storage project design is difficult to meet specifications.
National Standard “GB / T36558-2018 General Technical Conditions for Electrochemical Socher System” Requires Lithium Ion Battery Energy Conversion Efficiency of Lithium Ion Battery Whenesses should not be less than 92%, but in fact the manufacturer is difficult to achieve, domestic department and land electronic CL5231F Can system efficiency is 88%, TslaPowerPack energy storage system is 88% ~ 89%. Lithium-ion batteries in the user side energy storage system, in addition to the reference specifications of the lithium ion battery energy storage itself, more involve both the cooperation of both construction and equipment on the user side, the relevant design specifications and the construction of both specifications match, Correlation protection can use the building of the building to protect measures, both of which are not design or practical applications..
The above work involves multidisciplinary knowledge integration, to strengthen exchanges and collaboration in cross-professional fields. In summary, lithium-ion battery energy storage as an emerging application mode, its efficiency and energy advantage have been widely recognized. However, the study of lithium-ion batteries in user side energy storage engineering is still insufficient, and the relevant standard specification supports need to be supplemented, and further research on its attribute meaning, economic benefits, system design, construction operation guidance, etc.