Introduction to the reason why Tesla uses ternary lithium batteries

1. Better low-temperature discharge performance. my country has a vast territory and a complex climate. The temperature changes from the three northeastern provinces at the northernmost point to the Hainan Islands at the southernmost point. Take Beijing as an example. As the main market for electric vehicles, the highest temperature in Beijing in summer is around 40°C, while in winter it basically stays at around minus 16°C or even lower. Such a temperature range is obviously suitable for ternary lithium batteries with better low-temperature performance. However, lithium iron phosphate batteries, which value high-temperature performance, will look a little weak in winter in Beijing. Relative 25℃ capacity refers to the ratio of discharge capacity under different temperature conditions to discharge capacity at 25℃. This value can accurately reflect the attenuation of battery life under different temperature conditions. The closer to 100%, the better the battery performance. 2. Higher Energy Density According to the information supplied by BAK Battery, the leading domestic ternary material 18650 cylindrical battery company, the energy density of its 18650 battery has reached 232Wh/kg, and will be further increased to 293Wh/kg in the future. In contrast, the energy density of the current domestic mainstream lithium iron phosphate batteries is only about 150Wh/kg. According to the analysis of domestic battery industry experts, the energy density of lithium iron phosphate batteries can reach 300Wh/kg in the next few years. Hope is very slim. Unlike the bulky electric buses, for household electric vehicles, space always comes first. Lithium iron phosphate batteries with lower energy density will occupy a small amount of car space, and due to the heavier mass, the discharge life during use will also be greatly affected. Relatively speaking, the ternary lithium battery with higher energy density can not only deal with the weight problem, but also save space for the family car. Third, higher charging efficiency In addition to battery life, charging is also an important part of the actual use of electric vehicles, and the ternary lithium battery has a very big advantage over the lithium iron phosphate battery in terms of charging efficiency. The most common charging method currently on the market is constant current and constant voltage charging. Generally, constant current charging is used at the beginning of charging. At this time, the current is larger and the charging efficiency is relatively higher. After the voltage reaches a certain value, reduce the current and change to constant voltage charging, so that the battery can be charged more fully. In this process, the ratio of the constant current charging capacity to the total battery capacity is called the constant current ratio. It is a key value to measure the charging efficiency of a group of batteries during the charging process. Generally, the larger the percentage, the higher the amount of electricity charged in the constant current stage, which also proves that the battery has a higher charging efficiency. It can be seen from the table that when the ternary lithium battery and the lithium iron phosphate battery are charged below 10C, there is no significant difference in the constant current ratio. When the rate is above 10C, the constant current ratio of the lithium iron phosphate battery decreases rapidly, and the charging efficiency decreases rapidly. Fourth, the cycle life can be assured. For family cars, the rated cycle life of ternary materials and lithium iron phosphate power lithium-ion batteries far exceeds the actual user's habits, so you can rest assured in terms of service life. Taking the current high-capacity 18650 battery of BAK Battery as an example, after 1000 charge-discharge cycles, the battery capacity can still be maintained above 90% of the original. Since the author himself is also an electric vehicle owner, it is only during the coldest month of winter in the whole year. When the warm air is frequently turned on, the charging can be achieved every 2 days, and the rest is basically 3-4 days. Assuming an average charge for 3 days throughout the year, it takes about 6 times to charge in 1 year, and it takes about 8 years to complete the cycle life of 1,000 times. This basically exceeds the current average replacement cycle of consumers in my country. 5. Sufficient safe materials and processes The most harmful part of traditional internal combustion engine vehicles is the fuel that contains huge energy. If liquid fuels with low ignition point and explosiveness like gasoline leak, it is very easy to cause great safety hazards. The power lithium-ion batteries of new energy vehicles are monitored by a complete battery management system (BMS), and each battery can be controlled most accurately to prevent accidents. Take BAK 18650 battery products as an example. In terms of the process of single cell batteries, BAK chose to configure protective additives and reactive additives on the positive and negative electrodes to prevent safety problems caused by electrolyte analysis. At the same time, safety protection measures such as ceramic diaphragm and negative electrode ceramic coating are added to control the occurrence of accidents from the root cause. In addition, BAK's small cylindrical 18650 battery pack mode keeps a sufficient safety distance between each battery to ensure that the accident of a single battery will not affect other batteries. Automobile batteries have also gone through a long development process, and a batch of new ones have been eliminated. Lithium manganese oxide batteries were first proposed by the battery company AESC. This AESC is not a small one. It is a joint venture between Nissan and NEC. Ternary lithium batteries, as a rising star, have the highest energy density, but their safety is relatively poor. Regarding pure electric vehicles with required mileage, they have a broader prospect and are currently the mainstream direction of power lithium-ion batteries. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete the previous one: 18650 What are the advantages of lithium battery with and without protection board?