The progress of solid -state batteries exceeded expected, and semi -solid -state landing accelerated the loading.
Compared with traditional liquid batteries, solid batteries have obvious advantages in energy density and safety, and are considered one of the most potential next -generation battery technology. However, because its technology is still immature and the cost is still high, the industry generally believes that the time node of commercial applications is far from 2030. However, since 2022, enterprises have taken the semi -solid -state scheme as the intermediate route of transition, and have taken the lead in realizing the industrialization stage of loading applications. With the increase in car loading models, the scale of semi -solid batteries has expanded, and its economy is expected to increase, driving the development of the industrial chain simultaneously, or will accelerate the evolution process of the final form of a full solid battery.
The material system is comprehensively optimized, and the electrolyte is opened to open a new track.
The electrolyte is the key innovation point of solid -state batteries. The three major technical routes have the advantages and disadvantages: the highest vulcosion ion conductivity, the long -term development potential, but the stability is poor and the cost is high; the oxide conductivity is moderate and the stability is good. Fast; the polymer conductivity is limited, but the difficulty of application difficulty is a short -term choice.
The positive and negative electrode materials of solid -state batteries are iterating towards high -performance directions. It is expected to open the application space of high nickel triple yuan and silicon -based negative poles. Essence At present, there are many companies involved in solid -state batteries at home and abroad. Auto companies, R & D institutions, and battery companies, including many startups, and midstream materials companies, and midstream materials companies have invested new technology research and development layouts. The innovation of process technology and the change of the material system brings new opportunities to the entire industry chain.
From the perspective of in the section, domestic independent brands and new power car companies are at the forefront. The overall production capacity planning of supporting battery factories has entered a hundred GWH levels, and the development and production progress of electrolyte materials are relatively lagging. Yuanzhengji has the ability to mature mass production in China, and the size of the negative electrode of the silicon base needs to be volume.
Solid -state batteries are considered ideal solutions to solve the safety of lithium battery and improve energy density. As the next -generation battery technology route, it has a key industrial layout.
Since 2022, the research and development and industrialization of solid -state batteries has made significant progress, especially the technological progress and cost reduction of domestic enterprises in the field of semi -solid batteries have been greatly exceeded. The semi -solid battery achieved mass production vehicle in 2023, marking that the semi -solid battery has entered the first year of industrialization. With the production capacity planning of battery companies and the application of more vehicle companies' models, the industrialization process of solid -state batteries is expected to accelerate.
Compared with liquid lithium -ion batteries, the core variables of solid batteries on the material side are solid electrolytes and are expected to improve the penetration rate of high -performance positive and negative pole materials and soft bag packaging.
Solid -state battery: improve energy density and solve the ideal battery solution of safety problems.
Lithium -ion battery performance touches the ceiling, and the demand upgrade driver technology iterates. As the penetration rate of electric vehicles continues to increase, people's requirements for battery safety and mileage are getting higher and higher. As a mainstream technology route of the power battery, liquid lithium ion battery, on the one hand, the flammable and high corrosiveness of organic solvents in liquid electrolytes, lithium branches crystal problems that cannot be avoided during charging and discharge, triggers people's anxiety about battery safety; On the one hand, the energy density of liquid batteries has approached the ceiling under the restriction of the material system, and iterates to iterate. At this stage, in the case of serious excess homogeneous production capacity, get rid of cost -oriented, explore new technologies, seek breakthroughs in safety and performance, and become a new path of evolution of the power battery industry.
Solid -state battery is the current direction of the most potential battery technology.
Advantage: high security and high energy density
Solid -state batteries can essentially solve the main safety hazards of lithium -ion batteries.
Traditional lithium -ion batteries may occur in safety accidents such as spontaneous combustion and explosion, and the root causes come from flammable and volatile organic electrolytes. Excessive charging and internal short circuits will cause heat loss, and the electrolyte is ignited at high temperature, which eventually causes the battery to fire or explode. In addition, electrolyte corrosion, volatilization, and leakage may also bring serious hidden safety hazards to the battery system. The solid electrolyte itself is non -flammable, high -temperature resistant, non -corrosive, non -volatile, and the mechanical strength, thermal stability and electrochemical stability are better than the traditional electrolyte, which fundamentally improves the safety level of the battery.
The material system and battery structure are optimized, and the energy density has been greatly improved. Increased energy density is one of the primary goals of battery technology iterative upgrades. It is mainly achieved through two ways:
1) Using positive and negative pole materials with higher capacity and larger potential differences;
2) Increase the proportion of active materials in the battery. In liquid lithium -ion batteries, the approach corresponds to the application of high -performance materials such as high -nickel ternary and silicon carbon negative electrode, but the voltage window of the electrolyte directly limits the optional range of the positive pole material.
The two can be achieved through the improvement of the battery packaging process, the thickness of the fluid, and the increase of battery size. However, with the rapid development of the industry, the marginal effect of packaging and optimization of packaging and the weight loss of the collector has been minimal. The size of the battery size has continued to increase. Constrained by heat management and other issues. The solid battery breaks the various restrictions facing traditional lithium -ion batteries to achieve a leap in energy density.
According to the quality percentage of liquid electrolytes in the battery, lithium batteries can be divided into liquid batteries, semi -solid batteries, quasi -solid batteries, and full solid batteries. Among them, three solid -state, quasi -solid and all -solid state are called solid -state batteries.
The solid -state battery and the liquid battery follow the same charging and discharge principle, and replace the liquid electrolyte and diaphragm in the liquid battery with solid electrolytes to prevent the hidden dangers of flammable liquid leakage liquid. At the same time, the battery energy density is significantly improved. Focus on the direction of the world.
1) Solid -state battery can adapt to high voltage positive electrode materials. Compared with traditional electrolytes, the electrochemical windows of solid electrolytes are increased to 5V. At the same time, the material system with serious response to the interface in the liquid battery, such as high -nickel positive poles, manganese -containing compounds with manganese -soluble problems, and high -voltage positive material compatibility is more compatible. Okay, open the energy density ceiling.
2) The mechanical properties with good solid electrolytes provide possibility of the use of lithium metal negative poles. Lithium metal is used as a negative electrode, and the theoretical capacity is 3860 mAH/G, which is about 10 times the graphite. From the perspective of capacity, it is the most ideal negative form. However, the stability of lithium metal is poor. If the traditional liquid lithium battery uses metal lithium negative electrodes, lithium branches spiny the diaphragm will be generated during the cycle, resulting in short circuit inside the battery, affecting safety and cycle stability. The solid electrolyte has good mechanical properties, can effectively suppress the formation of lithium branches, compatible with lithium metal negative electrodes, and can achieve a leap in energy density.
3) PACK design simplifies and the system weight is reduced.
The function of solid -state electrolyte electrolyte and diaphragm is in one body. If the use of lithium metal negative electrode is used, the distance between the poles will be greatly reduced;
The single battery cells can be linked in series and densely stacked to achieve the voltage effect, thereby improving the manufacturing efficiency, reducing the size of the packaging, and improving the volume energy density. In addition, due to the excellent heat resistance of solid electrolytes, the demand for system thermal management of solid -state batteries has decreased, which further reduces the weight of the system.
The function of electrolyte is to build a channel for lithium ion between positive and negative electrodes, and the indicator of the smooth situation of lithium ion transportation is called ionic conductivity. On the electrode and electrolyte interface, the contact method of traditional liquid electrolytes with positive and negative electrodes is liquid-solid contact. The interface is well wettable. -Solid interface contact, small contact area, poor tightness, ion conductivity is usually two levels of magnitude lower than liquid electrolytes. This feature has led to limited fast charging performance of the battery. Because the solid-solid interface is rigid contact, it is more sensitive to the volume of the electrode material. The stress accumulation during the charging and discharge process can also cause the electrochemical performance attenuation and affect the cycle stability of the battery. How to take into account the guidance rate, reduce side reactions, and reduce impedance is still the direction of the current industry.
The solid -state battery system usually uses high -performance positive and negative pole materials. The material itself has not really realized large -scale commercial use, and the price is higher than that of traditional electrode materials. The cost of raw materials is much higher than liquid batteries.
In terms of manufacturing, the development of mass production process is more lagging behind the material system. Some electrolyte systems have strict requirements on the production environment and further raising the cost of manufacturing.
The three major routes of solid -state electrolytes have been focused on layout. The design and development of solid -state electrolytes is the key to the development of solid -state battery technology. The ideal electrolyte material should have high-ion conductivity (> 10-3 S/CM), wide-electrochemical chemical windows, and positive and negative electrode materials have good chemistry and mechanical stability.
At present, the mainstream solid -state electrolyte routes are mainly divided into three types: polymers, oxides and sulfides. Different solid -state electrolyte properties have their own advantages and disadvantages, and the technical route has not yet been concluded. Most of the sulfide systems are chosen by Japanese and Korean companies. For example, Toyota took the lead in promoting the mass production of all -solid battery in sulfide, while domestic and European and American companies mostly tend to choose oxide electrolyte routes.
The oxide conductivity is moderate and stable, which is favored by domestic enterprises.
The ion conduction rate of oxide electrolyte is generally 10-6 ~ 10-3s/cm. The dense appearance makes it have higher mechanical strength, with good stability in the air and high voltage tolerance. The poor deformation ability and flexibility require high temperature sintering, which is the main challenge.
Oxide solid electrolytes can be divided into crystal and amorphous electrolytes according to the form. Crystal oxide electrolytic air and thermal stability are high, so it is easy to achieve large -scale production. The more extensive crystal solid electrolytes include garnet -type LLZO electrolyte, perovskite LLTO electrolyte, NASICON LAGP and LATP electrolyte. Among them, LLZO ion conductivity is high and stable for lithium metal. Although the sintering temperature brings higher costs, we believe that the application potential is relatively large in the long run. Insidation of ullen solid electrolytes is mainly Lipon -type solid -state electrolytes, low ionic conductivity, and adapted film batteries, so it has more application prospects on electronic equipment with low capacity demand.
Sulfide ionic conductivity is the highest, but the stability poor system is applied to practical applications.
Due to the high lithium ionic conductivity (10–4 ~ 10–2 S/CM), the sulfide solid electrolyte has received widespread attention, such as LGPS and LSP-SC's ionic conductivity at room temperature comparable to traditional liquid electrolytes. However, they have defects in terms of chemical stability and environmental stability, and they can easily react with water to generate toxic H2S gases. Therefore, their development is the most difficult, with strict requirements for the production environment and high mass production costs.
Among different types of sulfide solid electrolytes, ingraded LPS and crystalline LGPS, LPSCL, etc. with higher attention. Among them, LGPS ion conductivity is the highest, but because it contains precious metals, the cost of raw materials is high; LPSCL's ion conductivity can also reach 10-2 S/CM levels, and does not contain precious metals, so it is more cost-effective.
The polymer solid -state electrolyte is composed of polymer matrix (such as polyester, polyether, and polyamine, etc.) and lithium salt (such as LIClo4, LiaSF6, LIPF6, etc.). The main advantages of polymer solid electrolytes are high flexibility and high processability, so it has the possibility of low -cost scale production. However, the polymer electrolyte room temperature is low at the temperature at the temperature of the electrolyte. It is only 10-8 ~ 10-6 S/CM, and it needs to be heated to about 60 ° C to reach 10-4 S/CM. Research on polymers is mostly concentrated to improve its conductivity and thermal stability through chemical modification or composite materials.
The selection of solid -state battery electrode materials is wider, and high performance becomes a trend. Solid -state lithium ions can follow the traditional liquid lithium -ion battery material system, such as ternary/lithium iron phosphate positive pole, graphite/silicon carbon negative electrode.
The use of solid electrolyte instead of liquid electrolyte can largely suppress the interface reaction of the electrode, and no longer there is no voltage window limit for electrolyte, so the material performance boundary of the positive and negative electrode can be greatly broaden.
The positive electrode can be used along the high nickel triple yuan, manganese -based and high -voltage materials are expected to make breakthroughs. Among the existing positive materials with large -scale mass production capabilities, high nickel ternary positive poles are the largest than the capacity, which fits the performance goals of the high -energy density of solid -state batteries. In the long run, lithium -rich manganese bases and high voltage positive materials also have better application prospects in the solid -state battery system.
The lithium -rich manganese -rich capacity (250 ~ 400mAh/g), high working voltage, and low cost, but still need to solve the problem of poor circulation and magnification, low efficiency in the first week, and bloating oxygen at high temperature. After breaking through the 4.5V voltage window, the use of high -voltage positive materials such as lithium nickel manganate and olive Limpo4 is also possible. The working voltage platform of lithium manganate materials is as high as 4.7V, which is greatly improved compared to the 3.7V of the ternary material. At the same time, the voltage can reach 4.1V/4.8V/5.1V, respectively.
Silicon -based materials are an important iteration direction of negative electrodes, and lithium metal negative electrodes may be long -term goals. Silicon's theoretical compared to more than 10 times the graphite, but there are problems such as severe volume expansion, the decay of continuous reaction capacity with electrolyte, and poor performance performance. Silicon -carbon and silicon oxygen materials can inhibit volume expansion to a certain extent and improve electrochemical stability. It has been applied to the negative electrode of high -energy density batteries. It has a certain commercial maturity and is also suitable for solid -state battery system. Lithium metal is a more idealized negative plan, but the highly high lithium chemical activity still constitutes a great challenge for its industrialized application. Different types of solid electrolyte materials have different interface problems on metal lithium negative poles. Customized needs to be customized. solution. There are already a large number of research work around the interface side effects and lithium branches crystal problems. How to solve the problem of lithium negative interface and adapt to large -scale production needs is still a challenging topic.
Wet technology and liquid batteries overlap high, but the process is tedious and costly.
In the first step, the electrolyte of sulfide and oxide will react with the water, so the water base process cannot be used, and only organic solvents can be used. The drying and recycling energy consumption will be significantly lifted.
The second step is coated. Although the process is relatively mature, the large -scale production of solid electrolyte film is still to be verified. The third step needs to make the electrolyte layer density to ensure good contact with the polar sheet. The electrolytes of vulcanizes can be used for voltage/roller compression processes, while the oxide electrolyte has poor ductility and can only be sintered by high temperature, but the temperature cannot exceed 1000 ° C. The temperature cannot exceed 1000 ° C. Otherwise it will lead to the decomposition of side reactions and positive materials.
The potential for reducing the cost of dry method, and the application of scale is yet to be studied.
In order to improve production efficiency and reduce costs, solid batteries or tendencies are used to use solvent -free dry electrode technology. The drying electrode technology contains the average mechanical drying and drying process of active materials, adhesives and conductives. Dialogue use, improve the utilization of active materials. In the industry, only Tesla claimed that the dry graphite negative electrode was applied to the 4680 battery, which was not mass -produced; most of the other companies' dry -method electrical electrodes were in the stage of process and equipment development.
The stack is the ideal solid battery structure, and the soft bag/square package is more advantageous.
Due to the poor flexibility of inorganic solid -state electrolytes, the square and circular wound structure will cause gaps in the material interface, and it is difficult to get compensation and submerged without electrolytes. Therefore, the stacked chip is the most ideal battery structure of the solid -state battery. The pole sheet and the electrolyte film are completely evenly contacted, and the parallel synchronous expansion contraction can maintain good interface performance. The packaging method adopts soft bag/square, which can retain the integrity of the cell structure to the greatest extent when entering the shell. In addition, the pain points of flatulence and leakage in the liquid battery no longer exist, and the high ductility of aluminum plastic films can adapt to the overall shrinkage of lithium ions during the migration process. clear. During the packaging session, the solid battery can save the liquid injection steps, and the time to turn into time can be greatly shortened.
The semi -solid battery has a high visibility, and domestic enterprises have a leading layout. The road to commercialization of solid -state batteries is facing two major obstacles of technology and cost. The industry generally believes that its industrialization time node is around 2030. The semi -solid battery still retains the diaphragm and part of the electrolyte. The material system has a small change in the liquid battery, and the heavy coexistence of process equipment and liquid batteries can inherit the existing mature industrial chain and is expected to take the lead in realizing industrialization. Therefore, more domestic companies choose semi -solid batteries as the transitional product, and actively carry out R & D and production capacity layout. Representative companies include Wei Lan New Energy, Qingtao Energy, Ganfeng Lithium, and Huaneng Technology. At present, the energy density of the semi -solid battery verified by the car is up to 368 WH/KG, which is about 40%compared to the mature high -nickel ternary battery. According to our statistics, as of the end of 2023, the domestic semi -solid battery production capacity planning plan has reached 240GWh.
The advantages of solid -state lithium batteries in terms of energy density and safety have allowed major vehicle manufacturers to accelerate the embrace of solid -state batteries and use it as the main technical route of the next generation of power batteries. International car companies including Toyota, Nissan, BMW, and Ford are planned to launch electric models equipped with all -solid batteries between 2025 and 2030.
The industrialization conditions of all -solid -state batteries have not yet matured, and many difficulties still need to be resolved by academic and industry. Against this background, car companies, R & D institutions, and battery companies including startups and other startups are actively committed to the development and mass production technologies of the next generation of all -solid batteries. At present, companies and institutions participating in the development of solid -state batteries are mainly concentrated in China, the United States, Japan, and South Korea. Japan: Leading in car companies, the earliest R & D layout, and the leading technology and patents worldwide. Toyota is one of the pioneers in the global solid battery field, with a leading patent layout. In 2019, it cooperated with Panasonic. In 2021, it jointly launched a prototype vehicle equipped with a solid battery. Mass production technology, strive to make full solid batteries enter a practical stage from 2027 to 2028. From the perspective of technical routes, Japanese companies generally bet the vulcosine electrolytes with the highest conductivity. The small cylindrical batteries used in the consumer electronics field have achieved batch shipments.
The solid battery mostly uses soft bag routes, or the demand for aluminum -plastic films.
With the advantages of the stacking process, high energy density, and gel -state packaging technology, soft bag batteries are expected to develop and apply in the field of solid battery. Aluminum -plastic films are the main packaging materials for soft bag batteries.
Due to the high difficulty of production technology, there are strict requirements in terms of resistance, depth, puncture resistance, electrolyte resistance and insulation, and the difficulty of controlling the consistency of the product after mass production. The only key material that has not yet achieved batch localization has not been achieved. At present, the main capacity of aluminum -plastic films in China is Xinlun New Materials, Zijiang New Materials, Daoming Optical and Ming Guan New Materials.