After the ups and downs, the share prices of the three giants of domestic cobalt industry-Han Rui Cobalt Industry, Huayou Cobalt Industry and Luomo Co., Ltd. almost all returned to the level of a year ago.
A month ago, when the word "cobalt-free battery" flashed in the cooperation between contemporary Amperex Technology Co, Limited and Tesla, the share prices of the three giants in the cobalt industry all collapsed. ? Afterwards, when more clues showed that the cobalt-free battery was a lithium iron phosphate battery that had nothing to do with cobalt from beginning to end, the industry began to suspect that this might be a "sneak attack" by lithium-ion batteries on ternary lithium batteries, and the concept of cobalt-free batteries was abused and "used as a gun".
Then, after reading it, Tesla issued a comment by burn: "Without cobalt, it is not necessarily lithium ferrous phosphate", which left people with infinite suspense. Some media combined this matter with the dry electrode production technology and supercapacitor technology obtained by Tesla's acquisition of Maxwell Company, and believed that Tesla would once again change the technical trend of the power battery industry. It is said that Tesla will release the technical progress of cobalt-free batteries on Battery Day in April this year.
However, considering Tesla's consistent tradition of skipping tickets and the objective laws in the field of materials, if we simply pay attention to the development of lithium batteries and automotive power batteries, we will find that this may be another traditional routine of "making a big news" in the battery field. Humans have been struggling for many years on the road of cobalt-free lithium batteries, and it is likely that they will continue to struggle for many years.
What is "cobalt-free"
Why can the word "cobalt-free" cause industrial earthquakes? It is no exaggeration to say that in the field of passenger car power batteries, this is equivalent to pulling out the foundation of the industry.
At present, the power battery of electric vehicles mainly uses two systems of cathode materials-lithium ferrous phosphate and ternary lithium, and ternary lithium occupies an absolute dominant position in the passenger car market. Moreover, represented by Tesla and other car companies, a pair of twin brothers are differentiated under the ternary lithium system: Tesla uses NCA (nickel cobalt lithium aluminate), and other car companies basically use NCM (nickel cobalt lithium manganate).
It can be seen that twin brothers can switch between Mn (manganese) and Al (aluminum), but the positions of Ni (nickel) and Co (cobalt) cannot be moved. To understand the importance of nickel and cobalt, we need to look at the layered structure, which is the basis of ternary lithium materials. The stability of layered structure is the premise of orderly operation of battery and the guarantee of battery performance and life.
In the layered structure of ternary lithium materials, the mission of nickel is to form a "skeleton" in which lithium ions can be embedded to improve the energy density of batteries. When the battery is charged, lithium ions will be inserted from the positive electrode, leaving holes, which may cause nickel ions to leave their posts and occupy the space originally belonging to lithium ions.
When lithium ion returns to the positive electrode during battery discharge, it can only go to the layer belonging to nickel, resulting in "mixed discharge of nickel and lithium". If the chain reaction is further triggered, the result is the collapse of the layered structure. When the battery materials are confused at the micro level, the macro result is that the cycle life of the battery is shortened, the battery capacity is reduced, and even the safety hazard is caused.
The role of cobalt is to make this framework more stable, inhibit the mixed arrangement of nickel and lithium, and keep the layered structure of ternary lithium cathode material as much as possible.
Unfortunately, cobalt is the most expensive material in power batteries. The price of lithium is still expensive, while the price of cobalt is about six times that of lithium. Moreover, because the main producing area of cobalt is Congo (Gold), the political situation is extremely unstable, and there is a risk of supply reduction and supply interruption. Therefore, whether in order to reduce costs or ensure the safety of the supply chain, it is of practical significance to find a battery material scheme with little or no cobalt.
In fact, the power battery industry has been on the road of "decarbonization". Tesla is a pioneer on this road.
When the first car Roadster went on the market in the early years, the battery cathode material used by Tesla was lithium cobalt oxide. Lithium cobalt oxide can be said to be the predecessor of lithium battery industry. In 1980s, when Sony took the lead in commercializing lithium batteries, it chose the lithium cobaltate route. Lithium cobaltate has a good cycle life and the highest volume-energy ratio among all materials, which is especially suitable for consumer electronic products (in fact, lithium cobaltate is still widely used in batteries of notebook computers, mobile phones, charging treasures and other products today).
However, lithium cobalt oxide is not suitable for vehicle power batteries because of its low actual energy density, low safety performance and large cobalt content.
In its own second-generation power battery, Tesla replaced the cathode material with NCA, which reduced the battery cost on the premise of ensuring the battery capacity and safety. In 20 18, Musk said on Twitter that the cobalt content in Tesla power battery had been reduced to below 3% at that time, and its ultimate goal was to erase cobalt from its own battery.
On NCM, the brother material of NCA, the industry is also advancing along the road of reducing the amount of cobalt-the material ratio of nickel, cobalt and manganese is from1:1to 5:2:3, and it has applied for 8: 1: 1 in the past two years.
But before Tesla, no one dared to shout the slogan of "no cobalt". Because no one can predict whether the booming ternary lithium materials will collapse after cobalt is completely removed. Tesla's voice has triggered various efforts in the industry in cobalt-free batteries.
Four cobalt-free ways
Although "cobalt-free" sounds subversive, from the specific path, the technical system of lithium batteries has not changed dramatically.
On the one hand, the pursuit of cobalt-free led to the revival of lithium-iron batteries. Originally, due to the limitation of theoretical energy density, lithium iron battery lost its competitiveness in the passenger car market. But since last year, BYD and Contemporary Ampere Technology Co., Ltd. have successively launched blade batteries and CTP(Cell? Where to? Pack) battery technology, on the premise of not cutting the battery material, improves the energy density of the battery system by changing the structure, and basically reaches the level of lithium ternary 5:2:3 material.
This innovation in engineering method, rather than in material system, combines the advantages of lithium ferrous phosphate in battery cycle life, safety and cost, and makes lithium ferrous phosphate glow with new vitality. BYD launched a brand-new flagship model "Han" on this basis, and Contemporary Ampere Technology Co., Ltd. got the Tesla model on this basis? 3 battery supply order for standard battery life version.
1, "as long as manganese" spinel lithium manganate LiMn2O4, lithium-rich manganese-based Li2MnO3.
2. "just nickel" LiNiO2.
3. spinel lithium nickel manganate LiNi0.5Mn 1.5O4, both manganese and nickel are needed.
4. The genre of "mixing something else" is NiAl/NiMg, etc. This is Tesla's route.
The work of this route is mainly carried out by Jeff, the "father of ternary lithium" who has cooperated with Tesla for a long time. What the Dahn team did was to use nickel as the main material (accounting for 95%) and dope magnesium, aluminum or manganese to completely replace cobalt in the cathode material. According to the paper published by Dahn team, the experimental results show that magnesium and aluminum have similar effects to cobalt and can stabilize the layered structure.
Different schemes have their own troubles. For example, lithium nickelate is not safe; Lithium-rich manganese base is too short-lived; The energy density of spinel lithium manganate is too low; Spinel lithium nickel manganate solves these problems, but it is full of difficulties in production. Generally speaking, due to the pursuit of high energy density in power battery industry, high nickel series is paid more attention by the industry. However, the safety and life of the cobalt-free battery are more prominent after the cobalt which plays a role in stabilizing the structure is erased.
Where's Jeff The Dahn team seems to have found a good solution to the problem, which can achieve a smooth transition on Tesla's existing battery technology route and solve various problems without cobalt batteries.
However, it should be noted that when lithium ferrous phosphate re-entered the passenger car stage with the help of blade battery and CTP technology, and once became the representative of cobalt-free battery, the technology of cobalt-free battery derived from ternary system mostly stayed in the laboratory stage.
The gap from laboratory to commercialization
As mentioned above, cobalt-free batteries are not only the direction of Tesla's efforts, but also a hot topic in battery laboratories around the world.
But obviously, there will always be a gap to be bridged before a technology moves from laboratory to commercial application.
When Tesla's cobalt-free battery attracted the attention of the industry, Zhihu V "Frey Liu", an electrochemical engineering expert in a main engine factory, publicly questioned that Tesla's cobalt-free battery technology was not about to be commercialized. He believes that the experimental results of the Dahn team are obtained under the conditions of small batteries and a small number of charge and discharge cycles, which are completely different from the actual use conditions of electric vehicles, and the experimental conclusions should not be directly applied to large-scale commercial technology.
On the other hand, he also believes that there is no direct evidence that Maxwell dry electrode technology acquired by Tesla can obtain better performance and life than traditional wet electrodes.
At the same time, some insiders believe that Tesla may adopt a comprehensive optimization method, that is, make efforts in material innovation and engineering methods at the same time-the specific path is to use cobalt-free batteries, but compromise on the nickel content of battery materials at the expense of certain energy density performance, so as to improve the safety and cycle life of batteries. The short board of battery energy density can be solved by applying dry electrode combined with pre-lithiation technology (that is, charging more lithium at the negative electrode of the battery in advance to supplement the possible capacity loss of the battery in subsequent use).
In fact, this comprehensive optimization method is indeed in line with Musk's style-that is, on the basis of respecting the first principle, using the innovation of engineering methods to create new solutions in the industry. Is it the first generation model? The battery pack consisting of more than 8,000 cylindrical batteries on the S, or the first-class rocket that can be recycled by space exploration technology company, is based on the results of first-principles and reverse thinking in engineering methods.
However, the success of this thinking in the past does not mean that it can be perfectly copied on the "cobalt-free battery". As the insiders say, if the past success represents the future success, then the cobalt-free battery can't walk out of the reality of the laboratory for many years, and it can be deduced that the cobalt-free battery is just a castle in the air.
Conclusion:
Back to the beginning of the article, the three giants in the domestic cobalt industry were overwhelmed by Tesla's "cobalt-free battery" scandal, but it was not entirely a tragedy of the industry. However, some time ago, due to the hot speculation of capital on cobalt, the status of cobalt has risen to the point of being out of market demand. This is contrary to the cobalt removal work in the whole power industry.
The big news of Tesla's "cobalt-free battery" is only a breakthrough for market rules to play a role, prompting cobalt to "return to value".
Similarly, the battery field has always been prone to "breakthrough development" and "subversive discovery". But most of these breakthroughs are often proved afterwards, only verbal breakthroughs. In fact, the level of battery technology in human society has been showing a gradual picture.
It is difficult to determine whether cobalt-free batteries can become a reality; But what is certain is that there is no miracle in the development of batteries, and there is only one way-the gradual development of materials and the innovation of engineering applications.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.