Recently, there is no small news in the industry, Nissan announced the all-solid-state battery technical briefing, announced the progress of Nissan's research on solid-state batteries, and also established the first all-solid-state battery pilot factory in 2024, and in 2028 may launch a pure electric car equipped with solid-state batteries.
First of all, what is a solid-state battery?
Whenever we talk about the pain points of pure electric cars, it is always inseparable from short endurance, flammable and explosive, slow charging (although now fast charging is faster than refueling or slow), both afraid of cold and heat, driving time is longer and shorter, the core problem here is that the battery is not working! The core disadvantage of a pure tram is actually the disadvantage of the battery.
If you can still think of the chemistry and physics knowledge of junior high school, the essence of battery charge and discharge is chemical reaction (redox), what factors affect the chemical reaction remember? Concentration, temperature, pressure, structure, properties, etc., so look at the disadvantages of batteries on electric vehicles, the reason is that it is very susceptible to various factors.
So which part of the battery is most sensitive to the external environment? The structure of the battery can be simplified to positive and negative electrodes + electrolyte, now most of the battery electrolyte is liquid, if you have removed the battery, you will find that the battery has wet and wet mud-like things, compared to the positive and negative electrode materials, the electrolyte is easily affected by the environment, temperature, external pressure, etc., so to improve the performance and safety of the battery, the electrolyte from liquid to solid is a revolutionary program.
What are the benefits of solid-state batteries?
Solid-state batteries can solve almost all the problems of current automotive power batteries, such as not easy to burn, not easy to burst, no electrolyte leakage, will not occur at high temperatures, it is difficult to short circuit, insensitive to temperature, more resistant to high pressure, which is determined by the physical and chemical properties of solid-state batteries. At the same time, due to the absence of electrolyte, the choice of positive and negative electrode materials is wider, and the solid-state battery can easily achieve 300Wh/kg-400Wh/kg, and the highest energy density of the current automobile power battery is only 300Wh/kg.
Solid-state batteries are so good, do you go early?
Just like the nanomaterials and graphenes we are familiar with since childhood, a technology sounds good, but we have never seen it, and that may only be one reason: the technology is too difficult to mass produce. Interestingly, the technical difficulties faced by solid-state batteries are the advantages of common batteries, such as electrolyte you say it is not good, but can be completely in contact with the positive and negative electrodes, ion movement is also very smooth, so it can be seen that the material of the electrolyte and how to connect the positive and negative electrodes together is the core technical difficulty of solid-state batteries, so at present, it is difficult to achieve mass production both technically and from the cost.
Will Nissan really achieve mass production of solid-state batteries?
At Nissan's press conference, Nissan announced that it will conduct a feasibility study at the solid-state battery laboratory level in 2022; in 2024, it will build a pilot plant for solid-state batteries in Yokohama, Japan, and at the same time test and trial-produce key technologies for solid-state batteries such as mixing electrode materials with solid-state electrolytes and stacking batteries. And it is expected that in 2028, the cost of the battery pack is expected to be reduced to $75/kWh, and the charging time is shortened to 1/3, and it can be charged from 15% to 80% in 15 minutes at 25 °C.
In terms of core technology, that is, electrolyte material selection + bonding technology, Nissan chooses the sulfur solid electrolyte scheme, and the oil and electricity are fully contactable, so the overall ionic conductivity is very good, and the solid-solid contact is easy to form surface contact. The disadvantage is that the stability is poor, the chemical activity of sulfide is very strong, and the reaction with air, organic solvents, positive and negative active materials are very strong, not only in the battery is difficult to stabilize, the entire production, transportation links have become difficult. In terms of bonding technology, Nissan announced a plan to replace the traditional adhesive with a fibrous adhesive, so that the movement of the cathode active lithium ion is not hindered, thereby reducing the cell impedance.
In addition to Nissan, several major manufacturers have already begun to work on solid-state batteries, such as Volkswagen plans to start mass production of its solid-state batteries in 2024; Toyota and Panasonic are expected to sell cars equipped with solid-state batteries around 2025. BMW expects to launch the first concept car equipped with solid-state battery technology in 2025; Stellantis plans to launch its first solid-state battery technology by 2026, among others. There are also domestic BYD, Ningde era, etc., solid-state batteries are also their very key research and development projects.
It can be seen that basically in 3-10 years, the major factories will launch products equipped with solid-state batteries, but I think it is relatively not optimistic, because the development of battery performance so far is still very slow, the solution of the entire new energy industry around the battery pain point is still charging, battery management, battery structure, not because humans are not hard enough, but the physical and chemical limits are difficult to break through. The future is beautiful, but it will take a lot of time and a lot of patience to walk into the future.