CATL is rapidly breaking through all-solid-state battery research and development problems.

CATL all-solid-state battery research and development has recently entered the 20Ah sample trial production stage. A person familiar with the matter said that CATL's current solution can increase the energy density of ternary lithium batteries to 500 Wh/kg, which is more than 40% higher than existing batteries, but the charging speed and cycle life have not yet reached expectations.

This is a major progress and breakthrough.

Wu Kai, chief scientist of CATL, once said that the technology route that CATL currently invests more in research and development is the sulfide route. It has established an all-solid-state battery R&D team of nearly a thousand people, and has established a 10Ah all-solid-state battery verification platform.

In half a year, CATL has not only increased its R&D investment, but also expanded its all-solid-state battery R&D team to more than 1,000 people. It has also entered the 20Ah trial production stage, marking that CATL has entered the production technology exploration stage and begun to move towards mass production. go ahead.

From cautious stance to second to none

According to previous public statements by CATL Chairman Zeng Yuqun, CATL has invested 7 to 8 years in research on all-solid-state batteries. Based on this, it is estimated that the research began from 2016 to 2017. Late Auto news shows that in 2016, CATL invited Liang Chengdu, who had worked at Oak Ridge Laboratory in the United States (one of the world's top materials chemistry laboratories) for 10 years, to join CATL as co-president of the R&D system, directly leading CATL's sulfide All-solid-state battery R&D project team.

However, the team had less than 100 people at the time, and CATL's positioning of the team was to "understand the technological progress of the most cutting-edge laboratories and companies, and help senior executives make technical decisions." Even last year, Wu Kai was quite cautious in his external statements. He once said: "If Toyota says it can produce all-solid-state batteries today, I am skeptical. No one in the industry currently has the ability to mass-produce all-solid-state batteries. As for whether mass production can be achieved by 2027, as a technician , it’s hard for me to say accurately.”

Until this year, CATL frequently shared the research and development progress of all-solid-state batteries at industry events, including research level, technological progress, mass production time, comparison with peers, etc.

At the performance briefing in March, Zeng Yuqun stated that all-solid-state batteries are still far from commercialization, but CATL does not ignore this technology and has recently increased investment. It hopes to do the same in the field of all-solid-state batteries in the future. To be second to none.

Wu Kai once said that if technology and manufacturing maturity are used as an evaluation system (on a scale of 1-9), CATL's all-solid-state battery research and development is currently at a 4-point level, and the goal is to reach a 7-8-point level by 2027.

Four months later, CATL said in response to investor questions that "small batch production of all-solid-state batteries is expected to be achieved in 2027."

At an industry conference in September, Zeng Yuqun still said that CATL's all-solid-state battery research and development is currently at a 4-point level, but rarely made a high-profile statement that compared with the situation around the world, CATL's research should be regarded as "a big step ahead", or in other words The English saying is "Second to none".

From cautious statements to claiming to be second to none, and now entering the 20Ah sample trial production stage, it should be relatively reliable for CATL to achieve small-scale mass production of all-solid-state batteries in 2027.

Three CATL solid-state battery patents newly "released"

Along with the good news that it has entered the trial production stage of 20Ah samples, CATL’s three solid-state battery patents have also been released.

On November 5, the State Intellectual Property Office announced three CATL all solid state battery patents, namely "modified solid electrolyte and its preparation method, solid-state battery and power device", "solid-state electrolyte membrane and its preparation method, solid-state battery, Electrical device" and "Solid-state battery cell and manufacturing method thereof."

Modified solid electrolyte and its preparation method, solid state battery and electrical device: the components of the modified solid electrolyte include a solid electrolyte substrate and a phase change toughening agent distributed in the solid electrolyte substrate; and in the In the modified solid electrolyte, the phase change toughening agent is mainly distributed at the product boundaries in the solid electrolyte; the phase change toughening agent can undergo phase change under the action of external force.

Solid electrolyte membrane and its preparation method, solid state battery, and electrical device: the solid electrolyte membrane includes a solid electrolyte material layer and a phase change toughening agent and fiber material dispersed in the solid electrolyte material layer, and the solid electrolyte material layer includes Inorganic ceramic solid electrolyte materials. The above-mentioned solid electrolyte membrane can effectively improve the mechanical properties of the solid electrolyte membrane, especially the fracture toughness, through the synergistic effect between the phase change toughening agent and the fiber material in the solid electrolyte material layer, thereby reducing problems such as dendrites and short circuits caused by fracture.

Solid-state battery cell and manufacturing method thereof: The solid-state battery cell includes an electrode assembly and a packaging shell. The packaging shell includes two packaging films, and the electrode assembly is arranged between the two packaging films. The two packaging films are connected and form a packaging part arranged along the circumferential direction of the electrode assembly. The packaging part includes a packaging area and a reinforcement area, and the thickness of the reinforcement area is greater than The thickness of the encapsulation area, and/or the hardness of the reinforcement area is greater than the hardness of the encapsulation area.

In the solid-state battery cell and its manufacturing method in this application, the packaging part is arranged along the circumferential direction of the electrode assembly to match the shape of the electrode assembly, thereby improving sealing stability. In addition, a reinforced area is provided on the packaging part. The thickness of the reinforced area is increased or the strength is higher, which can reduce the risk of wrinkles in the packaging part. The above structure can not only improve the packaging efficiency, but also reduce the risk of wrinkles during the packaging process, and improve the sealing performance of the solid-state battery cells.

Problem-solving ideas for all-solid-state battery technology

Judging from the above-mentioned disclosed patents, materials and manufacturing processes are CATL’s main directions for breaking through all-solid-state battery technology. This is also consistent with Wu Kai’s public statement.

At that time, Wu Kai said that there were three main technical routes for solid-state batteries, namely sulfides, oxides and polymers. No solid electrolyte is perfect. The sulfide route is progressing rapidly and is more likely to be the first to be mass produced. However, it must solve four major problems: solid-solid interface, lithium metal anode, solid electrolyte and manufacturing process.

In response to the problem of hard contact between solid and solid interfaces, CATL has developed multi-level full coating technology for single crystal positive electrodes. The stability of the interface structure is enhanced through multi-layer design. Currently, the gram capacity of high-face ternary positive electrodes can reach 230mAh/g. At the same time, CATL has also developed a multifunctional composite binder to help stabilize the conductive network of the pole pieces.

In response to the dendrite and polarization problems associated with lithium metal anodes, CATL uses phase change self-filling technology and lithiophilic interface layer design to inhibit the growth of lithium dendrites, induce lithium metal to be uniformly deposited on the surface, and build an interface ion transport "highway" ”, making the average Coulombic efficiency of lithium metal anode cycle >99.9%.

In response to the air stability and cost issues of sulfide electrolytes, CATL has developed a surface hydrophobic layer reversible coating technology that can keep the electrolyte stable in a -40°C dew point environment and achieve the preparation of electrolytes with high air stability. At the same time, CATL is also developing new synthesis routes and low-lithium content materials. Compared with the current price of electrolytes of more than 50,000 per kilogram, the new synthesis scheme can reduce mass production costs.

In order to solve the problem of solid electrode and electrolyte film formation process, CATL has opened up the dry/wet method of pole piece preparation and battery core integrated molding process.

The research and development and mass production of all-solid-state batteries is a very arduous task. Although CATL has overcome many problems, there are still many problems that need to be solved. It is exciting to see whether CATL, which has now entered the 20Ah sample trial production stage, will continue to disclose the progress of its progress during the year.