What are the advantages of lithium iron phosphate batteries?

The superiority of lithium iron phosphate batteries is going back to the previous two articles. We analyzed that the future electric vehicles should be mainly electric vehicles with small mileage and fast charging. At present, the dual-mode hybrid power of the family car with long battery life, and the pure electric vehicle of the bus market with long battery life. So what kind of battery does such a car need? 1. Safety First, safety is a prerequisite for automobiles. Cars are different from mobile phones and computers. Cars may encounter many unpredictable factors during high-speed driving, such as battery squeezing and impact caused by car accidents. Any one of the unfavorable factors may cause car crashes and deaths. We can see that some old scooters use inferior lead-acid batteries, and there is no safety guarantee. There are many cases of battery spontaneous combustion and burning by impact. Another example is Tesla's continuous fire incident in the past year, although there were no casualties in favor of Tesla's safety design. But at the same time, we must also see that these incidents were all very minor collisions. The collision itself did not harm the car or people, but the battery caught fire. What if it was a more serious accident? 2. High-rate discharge life The service life of an ordinary car is as long as several decades, and the battery of an electric car needs a cycle life of at least 3000 times in 10 years. As a relatively expensive component, it is very important that the battery life is equivalent to that of the car. It is necessary to ensure the performance of the vehicle and the interests of the car owner, so as to facilitate the promotion of the market. At present, only BYD Qin, which went on the market last year, has the battery life-long warranty for the electric vehicles of the world's automakers. The battery life is also the cycle life, and it is not a simple number given by battery parameters. The cycle life of the battery is closely related to the cycle state of the battery, such as discharge rate, charge rate, temperature, etc. Usually the cycle life derived from the battery laboratory data is obtained at a constant charge and discharge rate of 0.3C and a constant optimal temperature of 20 degrees. However, in the actual use of the car, the magnification and temperature are not constant. This is why the battery life of laptops, mobile phones, or battery cars is usually far less than the data given by the manufacturers in actual use. As for the low- and medium-range pure electric and long-range dual-mode hybrid electric vehicles, because they have fewer batteries, the discharge requirements will be higher, and the impact on life will be greater. For example, A123's lithium iron phosphate battery usually has a cycle life of more than 3000 times. However, the A123 lithium iron phosphate aeromodelling battery is used at a charge rate of 10C and a discharge rate of 5C. The life in the laboratory is shortened to only 600 times, but only about 400 times in actual use. It can be seen that the discharge rate has an impact on the life. . Taking BYD Qin as an example, only a 13KWH battery drives a motor with a peak power of 110KW. It can be calculated that when Qin is fully charged, its maximum discharge rate is as high as 8.4C. Especially when Qin has only 50% power, its maximum discharge rate can reach 18C. If the power is low, the discharge rate will exceed 25C, which will greatly shorten the life of the battery. Looking at the P85 kWh Tesla, the motor with a maximum power of 310KW looks very large, but the battery discharge rate is only 4C. When there is only 30% of the power, the maximum discharge rate is no more than 10C. Moreover, Tesla's large-capacity battery prevents the battery from being discharged with high power to a great extent. Through simple comparison, we can see the superiority of BYD battery's high-rate discharge life. 3. Temperature adaptability The impact of extreme cold on the battery is mainly manifested in the low charge and discharge rate and the reduction of electric capacity; the impact of extreme heat on the battery is mainly manifested in the reduction of life, high temperature safety, and decrease in charge and discharge capacity. The impact of extreme cold on the battery is relatively light, because the general lithium battery can be used below minus 20 degrees, and there will be heat during the battery discharge process, but the increase in energy consumption and the decrease in power cannot be prevented. The impact of extreme cold on pure electric vehicles is different from that of dual-mode hybrid vehicles. Because pure electric vehicles have no other power sources, they must rely on battery discharge and heating to reach a suitable temperature in extreme cold conditions, which will have a great impact on energy consumption and cruising range. Tesla's energy consumption per 100 kilometers and cruising range are significantly different in winter. 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: What are the benefits of increasing the battery from 18650 to 21700?