The development of chemical batteries has been more than two hundred years old. Lithium batteries have become the mainstream. You may be surprised that there are more than one hundred elements on the periodic table. Why do you have to choose "lithium" as a "little character"?
How lithium-ion batteries work
The new energy vehicle lithium-ion battery is a Rechargeable battery that relies on lithium ions moving between the positive and negative electrodes to generate current. There are many cathode materials for lithium-ion batteries, and they all exist in the form of embedded lithium compounds. Currently, the cathode materials for automotive power batteries are lithium iron phosphate, ternary lithium (divided into nickel-cobalt-manganese system and nickel-cobalt-aluminum system), and the like. The current mainstream of anode materials is graphite.
When the lithium ion battery is discharged, lithium ions are embedded in the positive electrode, and lithium ions are deintercalated in the positive electrode during charging, and lithium ions move between the positive and negative electrodes through the electrolyte and the separator during charge and discharge.
This is like a logistics car in the city, driving at points A and B. The constant and constant shuttles bring "current" to the city, and lithium is the most efficient and the most capable of bringing goods. That logistics car.
Why does lithium become the material for rechargeable batteries?
Before the application of lithium, humans have been looking for suitable battery materials as a device for storing electrical energy. People have tried various battery materials such as copper, iron, zinc, lead, mercury, magnesium, etc. The improvement direction of the battery is mainly to increase the capacity and The discharge performance and other indicators were the main factors, and lithium was finally selected as the material of the latest generation of rechargeable batteries.
Why is the active ingredient of the battery "lithium" instead of gold, silver, copper, iron and tin?
It is clear from the periodic table that lithium is the third element and the most advanced metal element.
Lithium itself is 6 atomic mass units, each lithium carrying a charge;
Compared to zinc, which has a wider range of applications in earlier batteries, its atomic mass is 66, and each zinc carries two charges. Obviously, using lithium as a battery material can bring about a significantly higher energy density. That is to say, lithium has a higher specific capacity as a battery material.
In addition, lithium-ion batteries have the advantages of no memory effect, high rate charge and discharge, low self-discharge rate, and high energy conversion rate.
From the earth to the space station to deliver supplies, although the light rockets are loaded less, but more launches several times, but also the cost of the proportion of rockets is low, lithium is like this more efficient light rocket?
Why does the ternary lithium battery replace lithium iron phosphate as the mainstream?
At present, most of the batteries used in pure electric vehicles have abandoned the positive electrode material of lithium iron phosphate and switched to ternary lithium materials. The main reason is because of higher battery performance requirements, that is, higher cruising range. Claim.
For example, the same cost motorcycle can run much faster than the car, but the safety of the iron on the two wheels will be less, which is very similar to the difference in personality between lithium iron phosphate and ternary lithium battery. .
The advantages and disadvantages between lithium iron phosphate and ternary lithium are obvious. The disadvantage of lithium iron phosphate is low capacity but better safety. The energy density of ternary lithium battery is obviously high but the safety is relatively general, in order to pursue higher endurance performance. , ternary lithium has become the current mainstream.
Why is the purpose of the battery's active ingredient "lithium" different formula cathode materials?
It is precisely because of the energy density that lithium iron phosphate is gradually replaced by “ternary lithium” batteries for the following reasons:
The energy density of the ternary lithium battery is obviously high, and the most direct benefit is that the cruising range can be increased;
The subsidy policy in 2018 and before directly encouraged high energy density batteries;
The new positive electrode material of the ternary lithium battery has a greater potential for energy density, such as NCM811 (nickel-cobalt-manganese ratio of 8:1:1).
Why is it called "Ternary Lithium Battery"? What is the purpose of different formulations of cathode materials?
The term "ternary lithium battery" is actually a very simple source.
Lithium-ion batteries use an embedded lithium compound as a positive electrode material. In order to improve battery performance, different combinations of materials have been tried to improve battery performance. Currently, "nickel-cobalt-manganese (NCM)" and "nickel-cobalt-aluminum (NCA)" have been found. The positive electrode materials of the two systems perform better because the two types of positive electrode materials have three active ingredients, so they are called "ternary lithium" batteries.
Some models of Tesla and other brands use nickel-cobalt-aluminum (NCA) system. Most other pure electric vehicles use nickel-cobalt-manganese (NCM) battery. According to different formulas, they are divided into NCM523, NCM111, NCM811, etc. Is the ratio between the three elements.
The more or less each element will directly affect the battery performance. At present, the main energy of the company's research and development is on the formula, just like the flavor of each stew is similar but the taste is different. The performance of the same formula battery of different companies will also have difference.
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