Which is better, lithium battery or lithium iron phosphate battery?

At present, there are two mainstream battery technology routes on new energy vehicles, lithium iron phosphate battery and ternary lithium battery. Although these two batteries compete in many application fields, they are mainly in the field of new energy vehicles because This is the largest lithium battery application scenario in China. Since it is necessary to compete, there must be a comparison. The comparison of the cost performance of the battery can be carried out through the price of the car, and it is better to compare the performance of 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 experiments conducted by relevant laboratories, new energy vehicle manufacturers, and power battery manufacturers, although the test of each test inevitably has subtle differences in specific parameters, the judgments on the performance and inferiority of the two types of batteries tend to be consistent. To this end, we take representative parameters for comparison.

1. The passenger car chooses BYD and the car chooses Tesla. This is the difference in volume between the two. From the current technology, the energy density of the ternary lithium battery is generally 200Wh/kg, and may reach 300Wh/kg in the future; while the lithium iron phosphate battery is currently hovering at 100~110Wh/kg, and the individual can reach 130~150Wh. /kg, but it is very difficult to break through 200Wh/kg. Therefore, the ternary material power battery can provide twice as much space as lithium iron phosphate, which is important for cars with limited space. Tesla produces a ternary lithium battery, and BYD produces a lithium iron phosphate battery. Therefore, there is a saying that "the passenger car chooses BYD and the car chooses Tesla."

2. Also because of the high energy density and the small weight, the light weight and small footprint determine that the new energy vehicle of the ternary lithium battery consumes less power, so the speed is faster and the endurance is stronger. Therefore, the car can use the ternary lithium battery to run farther, and the lithium iron phosphate new energy car is basically used for the city bus, because a battery life is not far away, there is a charging pile to charge in a short distance.

3. Of course, the core of the passenger bus using lithium iron phosphate battery is based on safety considerations. The Tesla car fire accident is more than one, because Tesla's battery pack consists of 7000 pieces of 18650 ternary lithium batteries . If these units' batteries or the entire battery pack have an internal short circuit, they will produce an open flame and encounter extremes. In the event of a collision, a short circuit caused a fire. The material of lithium iron phosphate does not burn when it encounters a short circuit, and the high temperature resistance is superior to that of the ternary lithium battery.

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

5. Charging efficiency, ternary lithium battery is higher. The lithium battery is charged by the current limiting method, that is, the constant current charging is performed in the first stage, and the current is large and the efficiency is high. After the constant current charge reaches a certain voltage, it enters the second stage 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 capacity to the total battery capacity is called the constant current ratio. The experimental data shows that the difference between the two is less than 10C, but the distance is above 10C. When charging at 20C, the constant current ratio of the ternary lithium battery is 52.75%, and the constant current ratio of the lithium iron phosphate battery is 10.08. %, the former is five times the latter.

6. Cycle life, lithium iron phosphate battery is better than ternary lithium battery, the theoretical life of ternary lithium battery is 2000 times, but basically to 1000 cycles, the capacity is reduced to 60%; even the best brand in the industry Sla, after 3,000 times, can only maintain 70% of the electricity, while lithium iron phosphate battery goes through the same cycle, and 80% of the capacity.

The comparison of the above six aspects can roughly lead to the relative advantages of the two to help answer the question of ternary lithium battery and lithium iron phosphate battery: lithium iron phosphate battery safety, long life, high temperature; ternary lithium battery weight Light, high charging efficiency, low temperature resistance, and the adaptability of the time and place due to the difference between the two is the reason why the two males coexist.