At present, there are two mainstream battery technology lines in new energy vehicles, lithium iron phosphate batteries and ternary lithium batteries, although these two batteries in many applications to compete, but the main line of competition in the field of new energy vehicles, because this is the largest domestic lithium battery application scenario, since the competition, there is bound to be a comparison, the comparison of battery cost performance through the price of the car can be carried out, and from the performance comparison Tributary lithium batteries and lithium iron phosphate which is better, it is necessary to set the conditions, the actual parameters of the two batteries to illustrate. According to the relevant laboratories, new energy vehicle manufacturers, power battery manufacturers experiments, although each test is not immune to the existence of specific parameters on the subtle differences, but the judgment of the advantages and disadvantages of the two battery performance tends to be consistent. For this reason, we take the representative parameters to compare.
1. Bus selection BYD, car selection Tesla. This is the difference in volume between the two. From the current technology, the energy density of ternary lithium batteries generally in 200Wh/kg, the future may reach 300Wh/kg; and lithium iron phosphate batteries are basically hovering at 100 ~ 110Wh/kg, individual can reach 130 ~ 150Wh/kg, but to break through 200Wh/kg is very difficult. Therefore, ternary material power battery can provide more than double the space than lithium iron phosphate to, which is important for the limited space of the car. Tesla production of ternary lithium batteries, BYD production of lithium iron phosphate, so there are "passenger cars, BYD, cars, Tesla" said.
2. Also because of the energy density, weight is also much smaller, light weight and occupy less space to determine the ternary lithium battery new energy vehicles consume less electricity, and thus faster, more range. Therefore, the car can run farther by choosing ternary lithium batteries, while lithium iron phosphate new energy vehicles are still basically used for city buses, because a range of not far, need a charging pile can be charged within a short distance.
3. Of course, passenger buses using lithium iron phosphate battery is more core is based on safety considerations. Tesla car fire accident more than one, the reason is: Tesla's battery pack consists of about 7000 18650 ternary lithium batteries, these units or the entire battery pack such as internal short circuit will produce open fire, encounter extreme collisions, short-circuit caused by fire. Lithium iron phosphate materials encounter short circuit will not burn, high temperature resistance than the ternary lithium battery is much superior.
4. Although lithium iron phosphate battery high temperature resistance, but ternary lithium battery low temperature performance is better, is the main technical route for the manufacture of low-temperature lithium batteries, at -20 ° C, ternary lithium batteries can release 70.14% of the capacity, while lithium iron phosphate batteries can only release 54.94% of the capacity, and due to the low temperature conditions, ternary lithium battery discharge platform is much higher than the lithium iron phosphate voltage platform to start also faster.
5. charging efficiency, ternary lithium batteries are higher. Lithium battery charging is the use of current-limited voltage method, that is, in the first stage to do constant-current charging, when the current is high, high efficiency. After the constant current charging reaches a certain voltage, it enters the second stage of constant voltage charging, at which time, the current is small and the efficiency is low. Therefore, the measurement of the two charging efficiency on the ratio of constant current charging power to the total capacity of the battery, called constant current ratio. Experimental data show that the difference between the two when charging under 10C conditions is not much, but more than 10C will pull away, in 20C charging, the constant current ratio of ternary lithium batteries is 52.75%, the constant current ratio of lithium iron phosphate batteries is 10.08%, the former is 5 times the latter.
6. cycle life, lithium iron phosphate battery is better than ternary lithium battery, ternary lithium battery theoretical life is 2000 times, but basically to 1000 cycles, the capacity decay to 60%; even the industry's best brand Tesla, after 3000 times can only maintain 70% of the power, while lithium iron phosphate battery after the same cycle, there is 80% of the capacity.
The above six aspects of comparison can be roughly derived from the relative advantages of the two can help answer the question of which is better: lithium iron phosphate battery safety, long life, high temperature resistance; lithium iron phosphate battery light weight, high charging efficiency, low-temperature resistance, the difference between the two so generated by the time and place of their respective adaptability is the reason for the coexistence of the two males.
