What are the common problems of power lithium-ion batteries?

Question 1: Regarding the industrial development of power lithium-ion batteries, the industrialization of power lithium-ion batteries is progressing rapidly, with serious two-level differentiation and insufficient high-quality output. With the rapid increase in the production and sales of new energy vehicles in China, the battery industrialization progress is also very rapid. According to the statistics of the Ministry of Industry and Information Technology, the installed capacity of batteries was 16GWh in 2015, 28GWh in 2016, 36GWh in 2017, and the demand in 2020 is about 100GWh. However, according to our rough estimate, the annual output of the battery industry in 2017 has reached 200GWh, far exceeding the actual demand. Question 2: The technological development path of power lithium-ion batteries. Battery technology progress. The picture below is the picture when we made the 12th Five-Year Plan. There has not been much change so far. This is because of the current system of cathode materials and anode materials. All types are determined, but the combination of different positive and negative materials can achieve different performance indicators and meet the use of different vehicles. Specifically, the first piece is the existing electrochemical system, which is relatively mature; the second piece is that the research and development should go to industrialization, but it has already reached the industrialization stage in advance. What are the reasons? It is because of long battery life, high specific energy requirements and subsidy policy guidance; the third is lithium sulfur and lithium air batteries are the future system. Question 3: Change trend of battery system energy density and grouping rate from 2015 to 2018. In 2015, the battery system energy density was 90Wh/kg and in 2017 it was 116Wh/kg. The development is relatively rapid, and it is relatively in line with the law of development. But by April of 2018, it had reached 137.5Wh/kg. Why is there such a big change from 2017 to 2018? Due to the introduction of the new subsidy policy. The battery system grouping rate was 63% in 2016, 67% in 2017, and 74% in the first few months of 2018, which is an average. Specifically, in 2017, the average cell energy density of the battery was 173Wh/kg, and the system average was 116Wh/kg. The calculated grouping rate was 67%, which is the difference from the cell energy density to the system energy density. Question 4: Analysis of the battery structure of the ternary system, the average energy density of the square, soft pack and cylindrical group efficiency cylindrical monomers is 187Wh/kg, the system average is 117.6Wh/kg, and the grouping rate is 62.89%; the average energy density of the soft pack monomers 171Wh/kg, the system average is 114.2Wh/kg, the grouping rate is 66.78%; the square cell energy density average is 144.17Wh/kg, the system average is 105.5Wh/kg, and the grouping rate is 73.18%. The structural defect of the cylinder like 18650, the cooling system and other structures should be added when arranging the arrangement so that its grouping rate is reduced; the square forming grouping rate is the highest, the easiest to group; the soft package, it One of the advantages is that the single unit can be made very high, but the group needs to add brackets, heat dissipation measures, etc. On the contrary, its grouping rate may not keep up with the square battery, and they will be in a three-thirds state for a period of time in the future. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Can ceramic-coated lithium battery separators improve battery safety?