Among the sodium ion batteries that CATL is expected to be put into production next year, there are both sodium ion power batteries used in electric vehicles and sodium ion energy storage batteries used in energy storage power plants.

It is understood that sodium ion battery is a secondary battery that relies on sodium ion to move between the positive and negative electrodes to complete charging and discharging. Its battery working principle is similar to lithium ion battery . During charging, sodium ions are released from the positive electrode and are embedded in the negative electrode through the electrolyte; the opposite is true when discharged.

Globally, research on sodium ion battery technology can be traced back to the 1970s, and even slightly earlier than lithium ion batteries, but in the 1990s, lithium ion batteries were successfully commercialized due to their better performance. The development of sodium ion batteries has been silent for a while. Since 2010, with the shortage of lithium resources and the safety of lithium ion batteries, sodium ion batteries have once again appeared on the stage.

On July 29, 2021, CATL released its first generation sodium ion battery. According to the company's press conference, the energy density of the battery cell cell monomer reaches 160Wh/kg; charging at room temperature for 15 minutes, the power can reach more than 80%; in a low-temperature environment of -20°C, it also has a discharge retention rate of more than 90%; the system integration efficiency can reach more than 80%. CATL said that the energy density of the second-generation sodium ion battery cell cell will exceed 200Wh/kg.

The Paper reporter learned from many industry insiders that compared with lithium-ion batteries, sodium ion batteries do not have much advantage in terms of energy density. Currently, the energy density of the cell cell of ternary lithium batteries can reach 200-350 Wh/kg, but sodium ion batteries are theoretically better in terms of low-temperature performance, fast charging and safety.

The outstanding advantages of sodium ion batteries are more reflected in the cost of raw materials. sodium ranks sixth in the crust element content, and is richer than the scarce lithium resources. The average price of lithium carbonate for domestic batteries has increased from about 40,000 yuan/ton in 2020 to about 500,000 yuan/ton at present, while the average price of industrial sodium carbonate has been within 3,000 yuan/ton for many years.

In addition, the positive and negative current collector of sodium ion battery can be made of aluminum foil. Since the aluminum current collector is prone to alloy reaction with lithium at low potential, the negative electrode of lithium ion battery can only be made of the more expensive copper foil .

Liu Yanlong, Secretary-General of the China Chemical and Physical Power Supply Association, said in an interview with the Paper reporter that theoretically, the material cost of sodium ion batteries can be reduced by about 30% compared to lithium ion batteries.

In terms of manufacturing process, CATL said that sodium ion batteries can be compatible with lithium ion battery production equipment and processes, and the production lines can be quickly switched to complete the rapid layout of production capacity. In terms of battery system integration, CATL has developed an AB battery solution that can achieve integrated and mixed sharing of sodium ion batteries and lithium ion batteries.

negative electrode hard carbon material may be the first to industrialize

However, Liu Yanlong told the reporter of The Paper, "At present, various materials of sodium ion batteries are mainly independently developed by various R&D companies, and the actual cost is still higher than that of lithium ion batteries. It requires industrial development and reduce the manufacturing cost of supporting materials."

In the view of industry insiders, sodium ion batteries have put forward higher requirements on the positive and negative electrode materials of the battery and the electrolyte materials, which has also become the reason why its industrialization has been delayed.

A report from a domestic information company DeepTech pointed out that, on the one hand, compared with lithium ion , the sodium ion mass and radius are larger, and the ion diffusion rate is lower, which is reflected in the battery performance. The theoretical capacity and reaction kinetic characteristics of the battery are inferior, and the modification of the positive electrode material is required. At present, layered oxides, polyanionic compounds and Prussian blue compounds are the three main development directions of sodium ion positive electrode materials.

On the other hand, although the internal resistance of sodium ion batteries is large, the instantaneous heat release volume during short circuit is less than that of lithium ion batteries and the temperature rise is lower, and it has inherent advantages in safety. However, sodium ion electrolyte is flammable, and the growth of negative electrode sodium dendrites is likely to cause short circuits. These safety problems need to be solved by negative electrode materials and electrolyte materials. Currently, the negative electrode materials of sodium ion batteries mainly include amorphous carbon (hard carbon, soft carbon), alloys, transition metal oxides, etc.

In terms of material selection of sodium ion batteries, according to Dr. Huang Qisen, Vice President of CATL Research Institute, CATL used Prussian white material with a higher capacity (Prussian white is one of Prussian blue compounds, which appears white due to high sodium content, and is called Prussian white) as the positive electrode material to rearrange the body phase structure of the material, solving the problem of rapid attenuation of Prussian white during the cycle. In terms of negative electrode materials, CATL has developed a hard carbon material with a unique pore structure, which has the characteristics of high capacity, easy deintercalation and excellent circulation. In terms of

electrolyte, CATL said that it has developed a new unique electrolyte system that is adapted to positive and negative electrode materials, which can be compatible with the current lithium-ion battery manufacturing processes and equipment in terms of manufacturing processes.

However, the large-scale preparation of these materials still faces considerable challenges. Taking the positive electrode Prussian blue material as an example, DeepTech's report pointed out that Prussian blue material is usually prepared by co-precipitation method. Before achieving large-scale preparation, it is necessary to solve the problems of crystal water and structural defects and low production efficiency caused by this preparation method.

According to CICC's analysis, the hard carbon materials of the negative electrode are expected to be the first to achieve industrial breakthrough. Hard carbon is a type of carbon that is difficult to graphitize even at high temperatures above 2800 degrees Celsius. However, hard carbon materials also have problems such as low efficiency of , Kulun efficiency (a performance indicator for quantifying the negative electrode material of lithium battery, that is, the ratio of battery discharge capacity to charge capacity in the first charge and discharge cycle), low long cycle stability and low compaction density. Low Coulomb efficiency will seriously affect the battery capacity and need to be improved through structural design, cation doping, surface functionalization and pre-sodiumization. What is the significance of

sodium ion battery in CATL?

When A shares closed on September 16, CATL's share price closed at 410.00 yuan, down 1.05%, with a market value of 1000.5 billion yuan. On that day, its market value fell below the trillion red line. In the 16 trading days since August 24th, CATL's stock price has been in a unilateral downward state, with the stock price falling from 524 yuan per share to the current level, with a drop of 21.8%, and the market value evaporated by about 340 billion yuan.

In the view of industry insiders, from the timeline, the sharp decline in CATL's stock price is not unrelated to the Inflation Reduction Act passed by the US federal government in mid-August.

According to the bill, U.S. consumers who purchase electric vehicles can enjoy a new tax credit of $7,500, but relevant conditions must be met, including 50% of key battery material parts must be produced in the United States or countries that have signed free trade agreements with the United States, increasing by 10% every year from 2024 to 2029 to 100%; at least 40% of key mineral raw materials in batteries must be mined or refined in the United States or countries that have signed free trade agreements with the United States, and increasing by 10% every year from 2024 to 2029 to 80%.

Not only that, under this bill, electric vehicle battery manufacturers produce batteries in the United States and receive a tax credit of $35 per kilowatt-hour, while battery module manufacturers will also receive a tax credit of $10 per kilowatt-hour.

For domestic power battery manufacturers led by CATL, this policy means that the space for the electric vehicle market in the United States has been greatly reduced, and on the other hand, it may face the competitive pressure of power battery manufacturers in the United States in the future on battery costs.

In the domestic power battery market, CATL continues to face the siege of its competitors. The domestic power battery installed data released by the China Power Battery Industry Innovation Alliance in August showed that CATL, , BYD , and China Innovation Airlines ranked in the top three, among which CATL installed capacity was 12.99GWh, accounting for 46.8%; BYD installed capacity was 6.08GWh, accounting for 21.9%.

But in terms of lithium iron phosphate battery installed capacity, CATL's absolute advantage is no longer obvious. In August, CATL's lithium iron phosphate battery installed capacity was 7.34GWh, accounting for 42.65%, while BYD's installed capacity was 6.05GWh, accounting for 35.18%. In July, BYD once surpassed CATL to rank first with an installed capacity of 6.01GWh and a market share of 41.9%.

Many industry insiders pointed out that in the field of electric vehicles, from a technical perspective, sodium ion batteries are a supplement to lithium ion batteries and cannot completely change the development direction of electric vehicle batteries, but will have a certain impact on the current market structure. In the field of micro-pure electric vehicles of RMB 30,000 to RMB 50,000, sodium ion batteries will have great market prospects.

Not only that, as the prices of upstream raw materials for lithium-ion batteries represented by lithium carbonate soar, CATL has promoted the industrialization of sodium-ion batteries. In a sense, it can send a signal to upstream raw material suppliers of lithium-ion batteries. The growth of demand for lithium-ion batteries in the future may slow down, thereby stabilizing or even lowering the price of lithium-ion batteries.

In addition, judging from the comprehensive performance of sodium ion batteries, compared with electric vehicles, the more suitable scenario may be energy storage.

At the 12th China International Energy Storage Conference held in Hangzhou last week, the "2022 China Energy Storage Industry Innovation and Development White Paper" released by China Chemical and Physical Power Supply Industry Association pointed out that "sodium ion batteries overlap with lithium iron phosphate batteries in terms of energy density, fast charging, wide temperature range, environmentally friendly and high safety, making sodium ion batteries better compete with the application of large-scale energy storage." On June 28, 2021, the world's first 1MWh sodium ion battery energy storage system created by Zhongke Haina has been officially put into operation in Taiyuan.

At the end of June this year, the National Energy Administration of issued the "Twenty-five Key Requirements for Preventing Power Production Accidents (2022 Edition) (Draft for Comments)". The document stated that "Medium and large electrochemical energy storage power stations shall not use ternary lithium batteries and sodium sulfur batteries , and it is not advisable to use cascade power batteries; when selecting cascade power batteries, consistency screening should be carried out and safety assessment should be carried out in combination with traceability data."

This means that when competing with lithium-ion energy storage batteries, sodium-ion energy storage batteries also gain more policy space.

With the close introduction of relevant national support policies, the pilot project of energy storage capacity and electricity bills and spot market transactions, and the advancement of renewable energy distribution and shared energy storage projects, the energy storage market is in full swing in China. This has also become another important battlefield for CATL outside electric vehicles.

CATL's financial report for the first half of this year showed that in the first half of the year, its energy storage system's operating income reached 12.73 billion yuan, accounting for 11.3% of its operating income, and its energy storage system's revenue increased by 171.41% year-on-year.