The route dispute of power batteries has become a hot topic in the past two years, which is also the technical route represented by Ningde Times and BYD, two companies. Previously, ternary batteries occupied an absolute advantage in the market, the installed capacity was more than 70%, but in the past two years, the situation has begun to change, equipped with lithium iron phosphate batteries more and more models, even Tesla, a staunch advocate of ternary lithium batteries, has also begun to use lithium iron phosphate.
Some people put the difference between the two kinds of batteries, simple and rough to summarize that the energy density of ternary lithium batteries is greater, and the energy density of lithium iron phosphate batteries is low but safer. Today we will talk in detail about the difference between the two batteries.
Ternary lithium battery
Advantages: higher energy density, stronger charge and discharge performance, better consistency of the battery
Disadvantages: higher cost, poor thermal stability
Ternary lithium battery, that is, the cathode material uses nickel cobalt manganese oxide lithium or nickel cobalt aluminum oxide lithium ternary cathode material lithium battery, has been the mainstream of power batteries before, because the advantages of ternary lithium batteries are more prominent.
In the case of the previous power battery energy density is generally low, only ternary lithium batteries are selected, because of its high energy density, better consistency of the battery cell, and high charging and discharging efficiency, so the power of fast charging is often higher and the discharge performance is stronger.
However, its shortcomings are also obvious, whether it is a lithium nickel-cobalt aluminate battery, or a nickel-cobalt-manganese-oxide battery, especially the high-temperature structure of nickel-cobalt-aluminum is unstable, so the risk of thermal runaway is greater. In addition, in terms of cost, the cost of ternary lithium batteries is significantly higher than that of lithium iron phosphate batteries.
Lithium iron phosphate batteries
Advantages: Better thermal stability, longer life, lower cost
Disadvantages: low energy density, poor consistency, poor low temperature performance
Lithium iron phosphate battery is a lithium ion battery with lithium iron phosphate as the cathode material, so it avoids the danger of thermal runaway brought about by the instability of the high-temperature structure of nickel-cobalt aluminum, from the combination of chemical elements, lithium iron phosphate is a typical orthogonal crystal system, due to the P-O covalent bond bond bond energy is very large, so the stability of the high temperature case is better, in addition, its battery durability is also better, the general charge and discharge can be more than 3000 times, that is, it is more durable than ternary lithium batteries.
In addition, lithium iron phosphate batteries also have a very big advantage, that is, the cost, the cost of lithium iron phosphate batteries is lower than that of ternary lithium batteries, which is also an important reason why many models choose lithium iron phosphate batteries. At the moment when subsidies are declining, it is inevitable to do everything possible to reduce costs.
However, the disadvantages of lithium iron phosphate batteries are also more obvious, because the vibration density and compaction density of lithium iron phosphate batteries are very low, so the energy density is lower, and the energy density of lithium iron phosphate batteries has increased in recent years, but it is close to the bottleneck, so it can only start from the structure, and can only improve the energy density by removing the module and changing the physical method of the internal structure.
In addition, the charge and discharge performance at low temperatures is weaker, and the consistency of the battery cell is poor. In particular, the problem of poor battery consistency has been ignored by many people, and at present, car companies mainly improve the consistency of lithium iron phosphate batteries through the lamination process.
Some people mentioned that lithium iron phosphate batteries are safe, to the mileage or to die, to choose lithium iron phosphate. This kind of friend's brain is all single-circuit. At present, there is a kind of atmosphere on the Internet, that is, like to label a thing simply and rudely, lithium iron phosphate is safe, ternary lithium battery is energy density but unsafe, at every turn is that you want energy density or life, see anything is not black and white, the same as primary school students.
Why is it said that the car equipped with lithium iron phosphate battery is safer is not rigorous, because the safety of the power battery is a system engineering, in addition to the safety of the battery itself, the electronic control system, the thermal management system is also very important, for example, some car companies use a fuse fuse mechanism, and some use explosive fusing mechanism, the latter in the occurrence of battery short circuit, the speed of power failure is faster.
In addition, lithium iron phosphate battery we also introduced, although it does not have nickel cobalt aluminum high temperature structure instability, resulting in poor high temperature safety problems, but its battery consistency is generally a little worse, battery consistency will bring what problems? On the one hand, it will bring about a sudden cliff-like decline in battery capacity, and even stall problems. On the other hand, it also brings greater challenges to the electronic control system, otherwise it will also increase the risk of spontaneous combustion of the battery.
In layman's terms, the safety of ternary lithium batteries and lithium iron phosphate batteries is not absolute, but should look at the specific model in the electronic control, thermal management to do not do in place, for example, you say that steel armor is safer than leather armor, but if the steel armor only covers the chest, leather armor covers the whole body, it is not necessarily. From the current point of view, the means to improve the safety of the ternary are more than the means to increase the energy density of lithium iron phosphate, and the energy density of lithium iron phosphate batteries has almost reached the top.
Ternary lithium batteries and lithium iron phosphate batteries have their own strengths, not necessarily which side kills the other party, lithium iron phosphate batteries and ternary lithium batteries have their own strengths, the key or the market to decide, whether it is ternary lithium batteries or lithium iron phosphate batteries, are not perfect at present, I hope that these two power batteries continue to evolve, as soon as possible to achieve the replacement of the internal combustion engine assembly.