The competition in the electric vehicle market has always been a battlefield without smoke, just like a crowd of heroes vying for victory in the Central Plains. Those who win occupy the market, and those who lose are eliminated by the market. In this competition, battery energy density is a key technology. In ternary lithium batteries, the current mainstream cathode materials are NCM or NCA. How to improve their energy density has become a hot topic in recent years. Nowadays, the 811 battery stands out, with a single cell even exceeding 300Wh/kg? What is energy density? What impact does it have on new energy vehicles? Energy density refers to the energy that can be released per unit mass, and the unit is expressed in Wh/kg. The concept of 300Wh/kg means that 1kg of lithium battery can release 300Wh of energy.

　　If this is not intuitive yet, 300Wh is equivalent to 0.3kWh, which is 0.3 kilowatt hours of electricity. It can light up the 30W light bulb at home for 10 hours and charge the mobile phone 30 times. The energy contained in a lithium battery pack in a vehicle can reach 100kWh or even higher. Higher energy density can obviously effectively reduce the weight and size of the battery pack. This can not only improve acceleration performance, but also reduce power consumption per 100 kilometers. That is to say, when the volume of the battery compartment remains unchanged, the energy density is higher and the energy of the battery pack is higher. What is the current energy density of lithium batteries? Currently, mainstream lithium batteries mostly use ternary lithium batteries. According to the different proportions of nickel, cobalt, and manganese, nickel-cobalt-manganese ternary lithium batteries can be subdivided into type 111 and type 523. , 622 type and 811 type, etc. Nowadays, 523 and 622 type are the main ones, with a single energy density of 200Wh/kg. The 811 battery broke through 300Wh/kg in one fell swoop, which is equivalent to a 50% increase in energy density. This is equivalent to a battery compartment of the same size, which can carry more lithium batteries or significantly reduce the quality of lithium batteries.

　　What exactly is an 811 battery? NCM811 is a ternary lithium battery with a cathode material of nickel, cobalt and manganese and a content ratio of 80%:10%:10%. It is currently the lithium battery with the highest energy density and highest technical content. Due to the high technical barriers to NCA batteries and Japanese companies monopolizing the NCA material market, most Chinese battery manufacturers choose the NCM route due to multiple factors.

　　Why develop 811 battery?

　　First, the main purpose is to increase energy density. The nickel component can increase the activity of the material and increase the energy density. So go the high nickel route. The cobalt component is also an active substance, which can stabilize the layered structure of the material, thereby increasing the discharge capacity of the material. The manganese component plays a supporting role in the material and provides stability during the charge and discharge process.

　　Second, it must be cost, because the cost of cobalt has been rising. Reducing the cobalt content can reduce production costs. After using 811 batteries, the general cost can be reduced by 8%. Taking Model 3 as an example, the 2170 battery cell it uses reduces the cobalt content required in the cathode material to less than 10%, which is lower than the cobalt content in the next-generation NCM811 batteries produced by other battery manufacturers. This breakthrough reduced Tesla's demand for cobalt by 59%. While increasing the energy density, it also reduces the manufacturing cost of 2170 battery cells.

　　Third, it is mainly policy guidance. National policies continue to use power battery energy density as a key indicator to guide the development of the new energy vehicle industry, and at the same time directly link new energy subsidies to power battery energy density. In addition, according to the "Medium and Long-term Development Plan for the Automotive Industry", by 2020, the energy density of a power battery cell will reach more than 300Wh/kg, and it will strive to achieve 350Wh/kg and the cost will be reduced to less than 1 yuan/Wh. Therefore, under these three pressures, the development of 811 is unstoppable. What are the risks of 811 batteries? At the same time, we cannot ignore the possible hidden dangers of 811 batteries. As the nickel content increases, the stability of the cathode material decreases.

　　The main manifestations are capacity loss due to cyclic charge and discharge and accelerated attenuation of capacity in high temperature environments. On the one hand, this means that the service life of the 811 battery is reduced, and on the other hand, the risk of spontaneous combustion caused by thermal runaway increases. Which models now use this kind of battery? The new BMW X1 PHEV model is a plug-in hybrid model, not a pure electric model. BMW Brilliance X1 is also the first model to be officially equipped with 811 batteries. To know how much NCM811 has improved it, it is enough to see the improvement in its cruising range. The energy density of the battery core is as high as 280Wh/kg, the power capacity of the new model has increased from 14.7KWh to 24KWh, and the pure electric cruising range has also increased from 60 kilometers to 110 kilometers.

　　For a plug-in hybrid model, this is already a qualitative leap. The pure electric range of 100km allows most usage scenarios to be driven by pure electricity. At the same time, the greater the energy of the battery pack, the greater the discharge power, and the opportunity for the engine to intervene. Just less. For details, please refer to the BMW X1 plug-in hybrid long-range version, which is priced at 393,800 yuan. GAC AionS is GAC's initiative model this year. Its cruising range has exceeded 500km. Under NEDC operating conditions, the cruising range has reached 510km. Many reasons for this are that the Aions has increased power. Under the same battery compartment specifications, 811 batteries The energy density is higher, and the battery system energy density reaches 180Wh/kg. The battery pack energy is 58.8kWh. This enables it to break through the 500km endurance mark. For details, please refer to the price after subsidy of 139,800-205,800 yuan. GAC New Energy AionS is officially launched. The NIO ES6 is NIO's second model and was released at the end of last year. The car is equipped with an 84kWh liquid-cooled constant-temperature battery system. The ES6 also uses CATL's NCM811 battery. The system energy density reaches 170Wh/kg, and the cruising range reaches 510 kilometers under NEDC operating conditions.

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