lithium 18650 li ion battery

　　How does the lithium 18650 li ion batteryindustry find a reasonable balance between energy density and safety?

　　Nowadays, many companies are pursuing higher monomer and system energy density. In order to ensure more energy supply, the electrolyte of both the positive and negative electrodes cannot be reduced, and the thickness of the diaphragm can only be squeezed. The thickness of the lithium lithium 18650 li ion batteryseparator used to be 40 microns, but now it is only about 12 microns. Once this film is damaged, the consequences will be serious. The Samsung Note7 lithium 18650 li ion batteryfire in 2016 was caused by the separator being too thin.

　　At present, the theoretical energy density limit of ternary lithium batteries is around 350Wh/kg-400Wh/kg. There are still many engineering problems that need to be solved. Therefore, if there is no breakthrough in new materials, the specific energy of the lithium 18650 li ion batterymay hover between 300Wh/kg-400Wh/kg. Only on the premise of achieving breakthroughs in engineering technology can it be possible to increase the energy density of a single cell to 500Wh/kg and the energy density of a lithium 18650 li ion batterypack to more than 260Wh/kg.

　　However, the development and application of various materials takes 1-2 years, or even longer. The current national practice of adjusting system specific energy density once a year is inconsistent with the power lithium 18650 li ion batterysystem development cycle. The result is that it cannot be fully verified, leading to frequent fire accidents.

　　EV Century also interviewed Mr. Wang Zidong about his views on the current use of NCM811 batteries by many car companies. Mr. Wang Zidong said: Without sufficient verification of the lithium 18650 li ion batterysystem and insufficient thermal management system technology, these models are the walking time bombs he mentioned before, and he hopes car companies will pay attention to them.

　　Power lithium 18650 li ion batterysafety issues

　　1. During the lithium 18650 li ion batterymanufacturing process. Safety requirements are very high during the manufacturing process. There are no factories that make lithium batteries without accidents, including LG and Samsung.

　　2. During the lithium 18650 li ion batterypack integration process. The lithium 18650 li ion batterycells are exposed and there is a problem when assembling the lithium 18650 li ion batterypack.

　　3. Storage process. Why should batteries be stored after they are produced instead of being used directly by users? Because the manufacturing process requirements for lithium batteries are too demanding, it is difficult for these big-name companies to control the current domestic level, including the international level, perfectly. Only in the process of shelving will the bad things become apparent. For a good company, it takes 10-15 days. During this period, the minor flaw is that the lithium 18650 li ion batteryvoltage decays faster, and the major problem is that it catches fire.

　　4. During transportation. An accident occurred when a car transporting batteries went down a long slope for 10-20 kilometers. The temperature of the brake system was too high and the lithium 18650 li ion batteryignited.

　　5. Usage process. This is directly related to charging. The principle of all chargers on the market is completely wrong. This principle is a bit like when I took the subway this morning, I pushed it in from behind. When it was invented in 1970, it was called a rocking chair battery, and ions moved back and forth between the positive and negative electrodes. Nowadays, there is no reduction method that produces shaking in the charging process. The traction charging method should be used instead of pushing charging. Lithium is very active in the periodic table of elements. It is like being crowded in the subway. Everyone is blocked at the door. The more people are crowded, the more people are crowded. When everyone is blocked at the door, it creates a problem. You have seen many photos on the Internet of batteries catching fire while charging.

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