Solid-state batteries not only have high safety and high energy density, but also have excellent "high and low temperature" performance. All kinds of advantages make people look forward to them, and they are regarded as the next generation of power batteries, and also the strategic commanding heights for countries to compete. However, at present, all three technical routes have corresponding basic shortcomings that need to be solved urgently, and the cost is also an insurmountable hurdle for enterprises.
Toyota Motor Corporation recently announced at the technical briefing that it has found good materials to commercialize solid-state batteries from 2027 to 2028 and put pure electric vehicles equipped with all-solid-state batteries on the market. However, because Toyota did not publish convincing technical details, it caused public opinion to question.
Solid-state batteries not only have high safety and high energy density, but also have excellent "high and low temperature" performance. All kinds of advantages make people look forward to them, and they are regarded as the next generation of power batteries, and also the strategic commanding heights for countries to compete. Thirty years ago, Oak Ridge National Laboratory claimed to have built a solid-state battery, but it is a pity that it has not been mass-produced so far. In the past two years, with the popularity of new energy vehicles around the world, many companies have reported the progress of mass production of solid-state batteries, but after the news was exposed, there was no more.
According to the material system, solid-state batteries can be divided into three technical routes. Japan and South Korea are betting on sulfide systems. In Europe, the main route is polymer, while in China, the main route is oxide. Among them, Japanese and Korean companies, represented by Toyota, Samsung SDI and Hitachi, have profound technology accumulation and obvious first-Mover advantage, and the trend of joint research and development is obvious. However, these three technical routes all have corresponding basic shortcomings that need to be solved urgently.
Specifically, sulfide electrolyte has poor air stability, and when it is exposed to air, it will produce toxic gas. At the same time, with the destruction of electrolyte structure and the attenuation of electrochemical performance, the synthesis, storage, transportation and post-treatment of sulfide electrolyte need to rely heavily on inert gas or drying chamber. At room temperature, the ionic conductivity of polymer electrolyte is low, which makes the charging of polymer solid-state battery need to be completed in high temperature environment, which greatly limits its commercialization. Most oxide electrolytes have wider electrochemical stability "window" and better oxidation stability, but in order to ensure good interface contact between rigid oxide electrolytes and cathode materials, it is often necessary to sinter at high temperature, otherwise it will lead to serious interface chemical side reactions. In addition, some oxide electrolytes also have the problem of lithium dendrite growth.
At the same time, cost is also a difficult hurdle for enterprises to overcome. At present, the cost of semi-solid battery is much higher than that of commercialized liquid battery. According to industry research and calculation, taking NCM811 liquid battery and NCM811 semi-solid battery as examples, the cost of semi-solid battery increases by about 80% compared with that of liquid battery. Among them, the cost of solid electrolyte is the main new cost and the main cost in semi-solid battery, accounting for about 50%. Due to the change of electrolyte material, production process and lack of experience in product quality control, the cost of all-solid battery is higher than that of semi-solid battery.
There are five main indicators to measure whether a power battery can be mass-produced, namely, energy density, charge-discharge rate performance, cost, safety and cycle life. The laboratory research results of power batteries generally make a major breakthrough in one or several indicators at a certain stage, and it is possible to mass-produce them only when they meet the requirements of five indicators. In other words, as far as the current research and development progress of major enterprises is concerned, solid-state batteries seem to be "windy", but in fact they are "long and long", and the mass production is still quite difficult.
Compared with structural innovation, the improvement of battery materials is slower and indeed more difficult. However, being difficult does not mean not doing it. We often say that it is reasonable to do the "difficult and correct thing". From the perspective of technological change, the technological innovation of power battery has played a major role in promoting the development of automobile electrification. The reason why China’s new energy automobile industry can lead the world is that we have surpassed the power battery, and a global power battery giant like Contemporary Amperex Technology Co., Limited was born.
In the industrial transformation driven by the goal of "double carbon", the innovation of power battery has become the key to strengthen the competition level of new energy vehicles, build the national industrial competitiveness and stabilize the competitive advantage of enterprises. Whether it is the first country or the catch-up country of new energy vehicles, or the main enterprises of the power battery chain, they are all aiming at new technologies and laying out solid-state batteries. This is both a great challenge and a rare opportunity. Super-large-scale market advantage, leading industry-wide competitiveness and rising innovation make China more qualified to win the strategic commanding heights of power batteries.
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