There are two mainstream battery technology routes in new energy vehicles: lithium iron phosphate and ternary lithium batteries. Although these two batteries compete in many application fields, the competition in new energy vehicles is mainline because This is China's most extensive lithium battery application scenario. Since there is competition, there must be a comparison. The comparison of the cost performance of the battery can be carried out through the price of the car. In terms of performance, it is necessary to compare the ternary lithium battery and the lithium iron phosphate battery. By setting the conditions, the actual parameters of the two batteries are obtained. According to the experiments of relevant laboratories, new energy vehicle manufacturers, and power battery manufacturers, although each test inevitably has subtle differences in specific parameters, the judgments on the performance of the two batteries tend to be consistent. To this end, we take representative parameters for comparison.

1. Choose BYD for passenger cars and Tesla for vehicles. This is the difference in size between the two. From the current technology point of view, the energy density of ternary lithium batteries is generally 200Wh/kg and may reach 300Wh/kg in the future, while lithium iron phosphate batteries are currently hovering at 100~110Wh/kg, and some can go 130~150Wh. /kg, but it is tough to break through 200Wh/kg. Therefore, the ternary material power battery can provide twice as much space as lithium iron phosphate, which is very important for cars with limited space. Tesla produces ternary lithium batteries, and BYD has lithium iron phosphate batteries, so there is a saying that "BYD for passenger cars, Tesla for cars".

2. Also, because of the high energy density and much smaller weight, the lightweight and small footprint determine that the ternary lithium battery new energy vehicle consumes less power, so the speed is faster, and the battery life is more robust. Therefore, ternary lithium batteries can be used to run farther, while lithium iron phosphate new energy vehicles are used for city buses. Because the battery life is not far at a time, it is necessary to charge piles for charging within a short distance.

3. Of course, the core 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: Tesla's battery pack consists of about 7,000 18650 ternary lithium batteries. If the batteries of these units or the entire battery pack have an internal short circuit, an open flame will be generated. The collision accident, the short course caused the fire. The lithium iron phosphate material will not burn in the event of a short circuit, and its high-temperature resistance is much better than that of the ternary lithium battery.

4. Although lithium iron phosphate batteries are resistant to high temperatures, ternary lithium batteries have better low-temperature resistance and are the main technical route for manufacturing low-temperature lithium batteries. At minus 20°C, ternary lithium batteries can release 70.14% of their capacity. In contrast, Lithium iron phosphate batteries can only release 54.94% of their ability. Due to the low-temperature conditions, the discharge platform of ternary lithium batteries is much higher than the voltage platform of lithium iron phosphate batteries and starts faster.

5. The charging efficiency is higher than the ternary lithium battery. Lithium battery charging adopts the current limiting and voltage limiting method; constant current charging is performed in the first stage. At this time, the current is large, and the efficiency is high. After the continuous current charging reaches a specific voltage, it enters the second stage of constant voltage charging. At this time, the current is small, and the efficiency is low. Therefore, to measure the charging efficiency of the two, the ratio of the constant current charging power to the total battery capacity is called the constant current ratio. The experimental data shows little difference between the two when charging below 10C, but the distance above 10C will be widened. When setting at 20C, the constant current ratio of the ternary lithium battery is 52.75%. The constant current ratio of the lithium iron phosphate battery is 10.08 %, the former is five times the latter.

6. In terms of cycle life, lithium iron phosphate batteries are better than ternary lithium batteries. The academic life of ternary lithium batteries is 2000 times, but, at 1000 cycles, the capacity decays to 60%; Sla, after 3000 times, can only maintain 70% of the power, while the lithium iron phosphate battery has 80% of the capacity after the same cycle.

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