Starting from the 4680 battery, the lithium battery anode material has changed from graphite to silicon-based

Since 4680 battery, the lithium anode material is changed from graphite to silicon

At the “Tesla Battery Day” held in September 2020, Tesla subversively released the “4680 battery”.

This kind of battery is not only significantly larger than the 18650 and 21700 batteries, but also has a higher energy density. The energy of the single cell has been increased by 5 times, and the output power has been increased by 6 times. It is expected to reduce the price of power batteries by more than 56%.

The application scenarios of electric vehicles are relatively special, and the space capacity is extremely limited. In order to ensure sufficient cruising range, certain requirements are placed on the energy density of power batteries, which is also the key to restricting the development of the industry. The main reason why the efficiency of Tesla 4680 battery has been greatly improved lies in three aspects: electrodeless ear mode, dry electrode process, and the application of silicon-based negative electrode.

The electrodeless ear mode complements the dry electrode process, and its core purpose is to reduce the internal resistance of the conductive path, from the previous 20mΩ to 2mΩ.

On the other hand, the application of silicon-based anodes is expected to break through the theoretical capacity limit of traditional anodes and achieve a comprehensive breakthrough in the energy density of power batteries.

When the 4680 battery is officially released, the permeability of the silicon-based negative electrode will continue to increase

For a long time, the negative poles of power batteries have been calm, and the cost-effective advantage has made artificial graphite a recognized technical route in the industry. In the absence of new driving forces, each negative pole company has put the focus of development on reducing costs and increasing efficiency.

But this calm may be broken by the 4680 battery. When the 4680 battery is officially released, the permeability of the silicon-based negative electrode will continue to increase. Will the discharge of 4680 batteries be the beginning of the next industrial iteration of lithium battery negative electrodes? What is the reason that restricts the replacement of artificial graphite by silicon-based anodes to become the mainstream of the industry?

Negative Iteration History

The concept of lithium batteries was first proposed in the early 20th century, but it was not until 1991 that Japan’s Sony officially realized commercial production.
The first batch of lithium batteries used petroleum coke as the negative electrode, which was quickly eliminated due to its low specific capacity and replaced by a material called mesocarbon microspheres (MCMB).

Although MCMB has been significantly improved compared with the first-generation negative electrode materials, there is still the problem of low specific capacity. In addition, a large amount of organic solvent needs to be consumed in the preparation process, so the cost is always high, which is almost the same as the current negative electrode material. several times more.

Lithium batteries were born in Japan, and Japanese companies always had the absolute right to speak in the early stage of the industry. Before 2000, almost all of the anode materials of Chinese lithium battery companies were imported from Japan.

Shanshan Co., Ltd. was the first to realize the domestic replacement of MCMB. At that time, Shanshan Co., Ltd., with the help of the technical strength of Anshan Thermal Energy Research Institute, established China’s first MCMB production line, which successfully reduced the price of MCMB anode materials.

Almost at the same time that Shanshan Co., Ltd. mass-produced MCMB, Professor Wang Chengyang of Tianjin University also developed the related technology of MCMB, and then authorized this technology to Tianjin Tiezhong Coal Chemical Company. In 2008, Tianjin Tiecheng was acquired by Bertray

When China realizes the domestic replacement of MCMB, the market demand for lithium batteries has actually changed. Mobile phones and notebook computers have become the main landing scenarios of lithium batteries, which puts forward certain requirements for the capacity density of lithium batteries.

With the continuous improvement of the penetration rate of lithium batteries in the 3C digital field, graphite materials with higher specific capacity have begun to gradually replace MCMB. The first to replace MCMB is the natural graphite material, which was first completed by Berterry. Almost at the same time as natural graphite, there is artificial graphite. Although artificial graphite is slightly more expensive, it is not easy to expand, has good cyclability, and has a good charge-discharge rate, which is suitable for more application scenarios.

Comparison of negative electrode parameters of lithium battery

In general, the lithium battery negative electrode continues the industry iteration route of petroleum coke, MCMB, natural graphite, and artificial graphite. Specific capacity and expansion rate are the performance parameters of most interest.

In 2011, natural graphite has become the material with the highest market share, with a market share of 59%; artificial graphite ranks second with a market share of 30%, and MCMB’s market share is only 8%.

At that time, it was in the early stage of graphite replacing MCMB, and the market still regarded cost as the primary consideration. The physical and chemical properties of natural graphite and artificial graphite are not so different, so the market is more willing to accept natural graphite with higher cost performance.

Lithium battery anode material market structure

However, in 2015, the proportion of natural graphite anodes dropped to 55%, and plummeted to 16% in 2020; the market share of artificial graphite anodes increased from 30% to 84%.

Why has the artificial graphite negative electrode achieved the tendency of rolling natural graphite in recent years? The reason lies in the rapid outbreak of new energy vehicle track.

The artificial graphite negative electrode has the advantages of long cycle life and fast charge and discharge, which has led to the unanimous choice of power battery manufacturers to choose the slightly more expensive artificial graphite as the mainstream route.

Throughout the development of lithium battery anode materials, which lithium battery anode becomes the mainstream of the market mainly depends on the application scenario at that time. After the basic performance is satisfied, the core competitiveness of negative electrode manufacturers no longer depends on research and development, but on how to reduce costs and increase efficiency, which also leads to a generally convergent profit trend for companies in the entire industry.

Tesla opens the negative path

What determines the choice of anode materials is market demand, and Tesla’s 4680 battery solution is expected to break the long-term market consensus on anode materials.

What is the biggest change brought about by the 4680 battery? That is, compared with the 21700 battery, the capacity increase is nearly 5 times, the power increase is 6 times, and the cruising range is increased by 16%.

4680 Cylindrical Cell Concept

For a long time, electric vehicles have been trapped in the short cruising range caused by the low density of power batteries.

Previously, the industry mainly focused on the selection of positive electrode materials to improve the energy density of power batteries, but today there is still a battle between ternary batteries and lithium iron phosphate. Obviously, there is no consistent conclusion in the positive electrode industry. .

The significance of Tesla’s 4680 battery is that it breaks through the traditional thinking of battery manufacturers focusing on positive and positive electrodes, and instead uses battery structure and negative electrodes to improve and maximize the energy density and efficiency of power batteries.

For graphite anodes, the current capacity of high-end products has reached 360-365mAh/g, almost reaching the ceiling of theoretical capacity of 372mAh/g. When the energy density of power batteries can no longer perfectly meet the needs of electric vehicles, it is necessary to look for higher Anode materials with gram capacity have become the general trend.

Looking at all anode materials, only silicon-based materials can significantly improve the gram capacity of the anode, and it is very likely to become the next-generation anode product. But at the same time, the silicon-based anode also has fatal defects, which limit the rapid popularization of this technology.

First, the silicon-based anode has a large expansion ratio and is prone to deformation. Secondly, the cycle performance is significantly lower than that of the graphite anode, and the conductivity is not very good. Coupled with the high price, it is difficult for this technology to obtain downstream manufacturers. of favor.

Comparison of Si-based Anode and Graphite Anode

Due to these defects, it is difficult for silicon-based materials to be quickly applied to anode materials in a short period of time. The current solution in the industry is the method of silicon-based materials composited with graphite, which has been able to achieve a battery solution with a specific capacity exceeding 400mAh/g.

The triple change caused by the 4680 battery

Tesla’s 4680 battery solution is expected to bring a dramatic triple-industry change to the negative electrode of lithium batteries.

The entire negative electrode industry is transformed from graphite to silicon-based composite materials, which will be the first major change brought by 4680 batteries to lithium battery negative electrodes.

Before the 4680 battery, silicon-based materials have actually been added to the negative electrode scheme in a small amount by some manufacturers. For example, 5% silicon-based materials are added to the negative electrode of the 21700 battery of Tesla Model 3. Data shows that in 2020, the domestic shipment of silicon-based materials is only 9,000 tons, and the industry penetration rate is only about 2.5%.

However, the emergence of the 4680 battery is expected to drive the market demand for silicon-based anodes, and the penetration rate of the entire silicon-based material in the anode is expected to double.

Behind the increase in the permeability of silicon-based materials, the core conductive agent carbon nanotubes may become another beneficial material, which is the second change brought about by the 4680 battery.

Due to the poor conductivity of silicon-based materials, the first thing that needs to be solved after full volume is the conductivity problem. The industry generally adopts the method of adding conductive agent to solve it.

At present, the traditional conductive agent of “carbon black + conductive graphite” is widely used in the industry, but the traditional conductive agent is added in a large amount and mainly relies on imports. In recent years, carbon nanotubes are a new type of conductive agent that is on the rise, with a small amount of addition and obvious advantages.

Carbon nanotubes are tubular nanoscale graphite crystals with good electrical conductivity. Carbon nanotubes are often added to cathode materials as conductive agents to improve the conductivity of lithium battery pole pieces, which can improve the rate performance and cycle life of lithium batteries.

In 2014, carbon nanotubes were only an unpopular conductive agent with a proportion of 13.6%. With the release of power batteries in China, the penetration rate of carbon nanotubes has continued to increase, and the market share has increased by 2018. to 31.8%. Continuing the current trend, by 2025, the market share of carbon nanotubes is expected to exceed 60%.

Penetration of Conductive Agents for Lithium Batteries in China

China already has the independent production capacity of carbon nanotubes. At present, domestic companies engaged in carbon nanotubes include Tiannai Technology, Cabot, Qingdao Haoxin, Jiyue Nano, Defang Nano, Wuxi Dongheng, etc.

Among them, Tiannai Technology is the absolute industry leader. In terms of shipments, Tiannai Technology’s market share in 2020 is as high as 32.3%, while the second and third places are 23.8% and 19.6%, a clear gap.

The upcoming third change is that the 4680 battery may fundamentally change the current pattern of the negative electrode industry.

In 2020, China’s anode material market will be divided up by four major leading companies, with Beterui, Putailai (Jiangxi Zichen), Shanshan and Kaijin Energy occupying 22%, 18%, 17% and 14% of the market respectively. In terms of market share, CR4 has a total market share of 71%.

Competitive Landscape of China's Anode Market

At present, the market share of negative electrodes of various enterprises is mainly affected by the production capacity of graphite negative electrodes. With the outbreak of silicon-based materials in the future, the market share of the entire negative electrode may change dramatically, and those companies that have an early layout in silicon-based materials will be preempted. market share.

Focusing on the global silicon-based anode industry, Japan’s Shin-Etsu is the most technologically advanced, while in the Chinese market, Bettray is the industry pioneer, and Putailai and Shanshan are currently catching up.

As early as September 2020, Bertray’s silicon-based anodes have been officially put into production. The market expects that this year’s shipments will be around 3,000 tons, and the development speed is ahead of other companies. It is most likely to become the largest silicon-based anode. beneficiaries.

Putailai is currently the second largest in the negative electrode market. In terms of the layout of silicon-based materials, Putailai has cooperated with the Institute of Physics, Chinese Academy of Sciences, and has completed the second generation of products, and has participated in the testing and certification of downstream users. It is expected to start mass production in the next few years.

Shanshan Co., Ltd. mainly focuses on silicon oxide anodes, and has achieved batch applications in the consumer and small power markets. The power battery is still undergoing testing and certification, and it is also in the early stage of mass production.

In addition, Kaijin Energy, Zhongke Electric and other companies are also actively deploying silicon-based anodes, hoping to seize the next iteration of the anode industry.

In general, the transition of lithium battery anodes from graphite materials to silicon-based materials has become a recognized technical direction in the industry, and the official release of 4680 batteries may stimulate the overall demand for silicon-based materials, which will not only reshape the entire lithium battery anode industry pattern, but also It will also drive the development of the related conductive agent industry.

The 4680 battery solution is not Tesla alone. Battery manufacturers such as BAK Battery and Yiwei Lithium Energy have also begun to develop their own “4680 solution”. This means that the discharge of 4680 batteries will most likely become a high probability event, and this is also expected to be the beginning of the next iteration of the lithium battery negative electrode.

Leave a Comment

Your email address will not be published. Required fields are marked *

tycorun logo

TYCORUN ENERGY

We offer lithium ion battery products, solutions, and services across the entire energy value chain. We support our customers on their way to a more sustainable future.

Products

Recent Posts

Hot Posts

Contact Form Demo (#3)
Scroll to Top

Request A Quote

Email:info@takomabattery.com