Currently on new energy cars, there are two mainstream battery technology route, lithium iron phosphate batteries and ternary lithium batteries, although the two batteries compete in many application areas, but competition in the field of new energy vehicles as the main line, because this is the nation's largest lithium battery application scenario, since to compete, must have the comparison, The comparison of the cost performance of the battery can be carried out through the price of the car, and from the performance of the comparison of three lithium battery and lithium iron phosphate battery which is good, it is necessary to set the conditions, the actual parameters of the two kinds of battery is clear. According to the experiments of relevant laboratories, new energy vehicle manufacturers and power battery manufacturers, although there are subtle differences in specific parameters in each test, the judgment of the performance of the two batteries tends to be the same. To this end, we take representative parameters for comparison.

1. Byd for buses and Tesla for cars. That's the difference in volume. From the current technology, the energy density of ternary lithium battery is generally at 200Wh/kg, and may reach 300Wh/kg in the future. And lithium iron phosphate battery basically hovering at 100~110Wh/kg, individual can reach 130~150Wh/kg, but to break through 200Wh/kg is very difficult. As a result, ternary batteries can provide twice as much space as lithium iron phosphate, which is important for space-constrained cars. Tesla produces three yuan lithium battery, BYD produces iron phosphate lithium battery, so there is "bus choose BYD, car choose Tesla" said.

2. Also, because of the high energy density, the weight is much smaller, the light weight and small space occupation determine that the three-yuan lithium battery new energy vehicle consumes less electricity, thus faster and has stronger endurance. Therefore, the car can run farther with ternary lithium battery, while the lithium iron phosphate new energy vehicle is basically still used for city buses at present, because a endurance is not far, there needs to be a charging pile in a short distance to charge.

3. Of course, the use of lithium iron phosphate batteries in passenger buses is based on safety considerations. There has been more than one fire accident in Tesla cars. The reason is that Tesla's battery pack consists of about 7,000 18,650 tera-lithium batteries. If there is an internal short circuit in the battery of these units or the whole battery pack, open fire will be generated. And the material of lithium iron phosphate will not burn in short circuit, high temperature performance is much superior to three lithium batteries.

4. Although lithium iron phosphate battery is resistant to high temperature, ternary lithium battery has better low temperature resistance, which is the main technical route for manufacturing low-temperature lithium battery. At minus 20°C, ternary lithium battery can release 70.14% capacity, while lithium iron phosphate battery can only release 54.94% capacity. The discharge platform of ternary lithium battery is much higher than that of lithium iron phosphate battery and the voltage platform starts faster.

5. Higher charging efficiency, ternary lithium battery. Lithium battery charging is the use of current and voltage limit method, that is, in the first stage of constant current charging, at this time the current is large, high efficiency. After constant current charging reaches a certain voltage, it enters the second stage of constant voltage charging, at which the current is small and the efficiency is low. Therefore, the ratio of constant current charge to the total capacity of the battery is used to measure the charging efficiency of both, which is called constant current ratio. Experimental data show that there is little difference between them when charging under 10C, but the distance will be separated when charging above 10C. When charging at 20C, the constant current ratio of terpolymer lithium battery is 52.75%, and that of lithium iron phosphate battery is 10.08%, the former is 5 times of the latter.

6. In terms of cycle life, lithium iron phosphate battery is better than ternary lithium battery. The theoretical life of ternary lithium battery is 2000 times, but basically when 1000 times, the capacity attenuates to 60%; Even tesla, the best brand in the industry, can only retain 70 percent of its power after 3,000 cycles, while the lithium iron phosphate battery still has 80 percent of its capacity after the same cycle.

The comparison of the above six aspects can roughly conclude that the relative advantages of the two are helpful to answer the question of which is better between lithium ion battery and lithium iron phosphate battery: lithium iron phosphate battery is safe, long life and high temperature resistance; Terpolymer lithium battery has light weight, high charging efficiency and low temperature resistance. The adaptability of the two is the reason for the coexistence of the two.