Date: 2024-01-10 hits: 239
Recently, it was reported that the large Japanese battery company Maxell has developed a cylindrical all-solid-state battery with a capacity of 200 mah, which is 25 times the capacity of the traditional ceramic package (square). The new battery has the characteristics of strong heat resistance, long life, and good impact resistance, and is considered to be able to be used as the main power supply. It is said that Maxell's all-solid-state batteries have been adopted by Nikon's sensors for industrial machinery, etc., and orders are increasing.
On January 3, the US solid state battery QuantumScape said that its solid state battery passed the 500,000 km durability test of the German company Volkswagen. The test data also shows that electric vehicles equipped with QuantumScape batteries have a WLTP range of 500-600 kilometers, and can travel more than 500,000 kilometers in the full life cycle of the battery without any decline in battery capacity.
Although the development of all-solid-state batteries is accelerating from Europe to Japan, in view of technical difficulties and high costs, semi-solid-state batteries will become an important development direction of battery technology innovation and application in the next one or two years.
First of all, let's understand the difference between semi-solid state batteries and all-solid state batteries.
Semi-solid battery: compared with liquid battery, semi-solid battery reduces the amount of electrolyte, increase polymer + oxide composite electrolyte, wherein polymer is filled in the form of frame network, oxide is mainly added in the form of diaphragm coating + positive and negative electrode coating, in addition, the negative electrode is upgraded from the graphite system to the pre-lithium silicon based negative electrode/lithium metal negative electrode, and the positive electrode is upgraded from high nickel to high nickel high voltage / Lithium rich manganese, etc., the membrane is still retained and coated with solid electrolyte coating, lithium salt is upgraded from LiPF6 to LiTFSI, and the packaging method is mainly rolled/laminated + square/soft package, and the energy density can reach 350Wh/kg or more.
All-solid-state battery: Compared with the liquid battery, the all-solid-state battery cancels the original electrolyte, chooses the polymer/oxide/sulfide system as the solid electrolyte, and divides the positive and negative electrodes in the form of a thin film, thus replacing the role of the diaphragm. The upper limit of the polymer performance is lower, the oxide progress is faster, and the sulfide has the greatest potential in the future. The negative electrode is upgraded from the graphite system to the pre-lithium silicon based negative electrode/lithium metal negative electrode, and the positive electrode is upgraded from high nickel to ultra-high nickel/lithium nickel manganate/lithium rich manganese base, etc. The packaging method is laminated + soft package, and the energy density can reach 500Wh/kg.
Solid state battery interface is solid-solid contact, low ionic conductivity, poor interface stability, circulation, fast charge and other problems, restricting its commercialization process.
Low ionic conductivity at the material end: In solid state batteries, the interface contact between the electrode and the electrolyte changes from solid-liquid contact to solid-solid contact, and because the solid phase is non-wettability, the contact area is small, forming a higher interface resistance. At the same time, a large number of grain boundaries exist in the solid electrolyte, and the grain boundary resistance is often higher than the resistance of the material body, which is not conducive to the transmission of lithium ions between the positive and negative electrodes, thus affecting the fast charge performance and cycle life.
Poor cycle life: solid-solid contact is rigid contact, which is more sensitive to changes in the volume of the electrode material, and it is easy to cause the contact between the electrode particles and the electrode particles and the electrolyte to deteriorate during the cycle process, resulting in stress accumulation, resulting in electrochemical performance attenuation, and even the emergence of cracks, resulting in rapid capacity attenuation, resulting in poor cycle life.
All-solid-state battery interface contact problem is more serious, the process is not mature, the production cost is high. The lack of fluidity of solid electrolyte leads to problems such as small solid-solid contact area, increased impedance, and low overall conductivity, which restricts the industrial application of solid state batteries.
Solid electrolyte is the key to achieve high safety, energy density, cycle life performance. According to the type of electrolyte, it can be divided into oxide, sulfide, polymer three routes. The polymer system is the first to be commercialized in Europe, and its advantages are easy processing, compatible production process, good interface compatibility, and good mechanical properties. The disadvantages are low ionic conductivity at room temperature, slightly narrow electrochemical window, limited thermal stability and energy density improvement, which restricts its large-scale application. The oxide has the best comprehensive performance, the advantages are wide electrochemical window, good thermal stability, high mechanical strength, and the disadvantages are difficult to process, poor interface compatibility, and general electrical conductivity. On the whole, the preparation difficulty of oxide system is moderate, and more people and domestic enterprises choose this route, which is expected to take the lead in large-scale loading of semi-solid batteries by means of composite with polymers; Sulfide has the greatest potential for development, with advantages of high electrical conductivity, both strength and processing performance, and good interface compatibility, while its disadvantages are poor compatibility with cathode materials, poor stability to lithium metal, sensitivity to oxygen and moisture, potential pollution problems, and high production process requirements. Sulfide is currently in the research and development stage, but the subsequent development potential is the greatest, and after the process breakthrough, it may become the mainstream route in the future.
According to the current point of view, solid-state batteries have already been on the market, but they are not used in automotive power. If the vehicle scale solid state battery applied to the automotive power market is mass-produced, it will undoubtedly open up a new era.
The overseas market seems to be quite optimistic, and the direct development of vehicle gauge all-solid-state batteries; The domestic market is more robust and realistic, semi-solid state batteries have been mass produced and applied, the next step is the launch of all-solid state batteries.
In the past two years, many people believe that the solid-state battery era can be reached in 2030. However, based on the current trend, the solid-state battery era will come sooner, and major battery manufacturers need to prepare early!
