The electric vehicles that have been launched recently are basically ternary lithium batteries and iron phosphate batteries. So what is the difference between these two batteries?
When we buy a car or buy a battery, we inevitably have many questions. Everyone hopes to be able to determine whether the two batteries are good or bad, so as to make a choice. In fact, there is basically no individual or relevant department or unit to compare these two mainstream batteries. Because the two batteries have different performance and characteristics.
Ternary lithium battery
Ternary lithium battery refers to a lithium-salt lithium battery in which the positive electrode material is nickel salt, cobalt salt, manganese salt/lithium aluminate, the negative electrode material is graphite, and the electrolyte is lithium hexafluorophosphate. It has high energy density, good safety and stability, supports high-rate discharge and other excellent electrochemical characteristics, and has a moderate cost advantage. It has been widely used in consumer digital electronic products, industrial equipment, medical equipment and other small and medium-sized lithium battery fields. , and in the field of power lithium batteries such as intelligent robots, AGV logistics vehicles, drones and new energy vehicles, there are also digital categories (smart phones, tablet computers, notebook computers, electric toy cars, MP3/MP4, earphones, mobile phone charging treasures, Aircraft model aircraft, mobile chargers, etc.) have shown strong development potential.
Lithium iron phosphate battery
Lithium iron phosphate battery Lithium iron phosphate battery refers to a lithium ion battery that uses lithium iron phosphate as the positive electrode material. The negative electrode is also graphite. The electrolyte is also based on lithium hexafluorophosphate. No matter what state the battery is in, it can be charged and used at any time, and there is no need to discharge it first and then charge it. It is the safest lithium battery at present, the inside or outside is damaged, the battery does not burn, does not explode, and has the best safety; the battery does not contain any heavy metals and rare metals (rare metals are required for nickel-metal hydride batteries), non-toxic (SGS certified) , No pollution, in line with European RoHS regulations, for the absolute green battery certificate.
Compared
In the field of power batteries, lithium iron phosphate batteries and ternary battery technologies are the leading ones. In the two major technical fields, the company's core technical indicators are at the leading level in the industry. The energy density of lithium iron phosphate batteries is far lower than that of ternary lithium batteries, but its safety is generally considered to be better than that of ternary lithium batteries.
Due to the different performance characteristics and different application scenarios of lithium iron phosphate batteries and ternary batteries, the two major technical routes will be supported at the same time. Among them, lithium iron phosphate batteries have the advantages of high safety and long cycle life, which can meet more safety requirements. In the field of commercial vehicles with high operating frequency and higher operating frequency, and in the field of passenger vehicles with higher space and weight requirements, the high energy density ternary battery can achieve longer cruising range and better meet the needs of individual consumers.
Although lithium iron phosphate batteries are resistant to high temperatures, ternary lithium batteries have better low temperature resistance, which is the main technical route for manufacturing low-temperature lithium batteries. At minus 20°C, ternary lithium batteries can release 70.14% of their capacity, while Lithium iron phosphate batteries can only release 54.94% of their capacity, and due to 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.
Charging efficiency, ternary lithium battery is higher. Lithium battery charging adopts current limiting and voltage limiting method, that is, constant current charging is performed in the first stage, at this time, the current is large and the efficiency is high. After the constant current charging reaches a certain voltage, it enters the second stage of constant voltage charging. At this time, the current is small and the efficiency is low. Therefore, the ratio of the constant current charging power to the total battery capacity is used to measure the charging efficiency of the two, which is called the constant current ratio. The experimental data shows that there is not much difference between the two when charging below 10C, but the distance will be opened 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 5 times that of the latter.
In terms of cycle life, lithium iron phosphate batteries are better than ternary lithium batteries. The theoretical life of ternary lithium batteries is 2,000 times, but basically when 1,000 cycles are reached, the capacity decays to 60%; even if the industry's best brand features Tesla, after 3,000 times, can only maintain 70% of the power, while the lithium iron phosphate battery still has 80% of the capacity after the same cycle.
Summarize
In reality, the choice between the two batteries needs to be determined according to the hot and cold climate in my personal opinion. Cold places are more suitable for low-temperature resistant lithium iron phosphate batteries, and places with moderate temperatures are more suitable for ternary lithium batteries with breakthrough performance.
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