Until now, people's concerns about electric vehicles still exist, mainly reflected in range anxiety and safety anxiety. At present, electric vehicles are mainly loaded with ternary lithium batteries and lithium iron phosphate batteries, and the mainstream view in the industry is that the energy density of lithium batteries has reached its limit, and the thermal runaway problem is difficult to solve from the root.
The working principle of lithium batteries is not difficult to understand, which relies on the repeated transfer of lithium ions between the positive and negative electrodes of the battery to achieve charge and discharge. Among them, because the liquid electrolyte contains flammable organic solvents, when the system is short-circuited, the battery may spontaneously combust or even explode and other runaway situations. Moreover, the liquid is naturally sensitive to changes in temperature, and the working performance of the battery is naturally easily affected by temperature.
So, let's change the way of thinking, the electrolyte is not a liquid, is it okay to replace it with a solid?
A solid-state battery with many advantages
The first advantage of solid-state batteries is safety. Theoretically, the electrolyte can be conducted on the solid, at this time there is no need to set the electrolyte, diaphragm, the structure is more simplified, can effectively avoid the short circuit caused by positive and negative contact, and no leakage, good insulation, no corrosion, safety is greatly improved. Of course, to achieve it, it is certainly not as simple as directly replacing the electrolyte, and the solid-state battery still needs a positive and negative electrode material, which will be re-matched according to chemical properties.
Solid-state batteries also have a higher energy density. In addition, since the solid-state battery has no separator and electrolyte, it also saves nearly 40% of the volume and about 25% of the mass, so that more various materials can be put in. According to professionals, the same choice of lithium as a medium, the theoretical battery specific energy is expected to reach 500Wh/kg.
(Substances in the electrolyte will inevitably puncture the diaphragm)
Solid-state batteries are also less attenuated. For traditional lithium batteries, the liquid electrolyte in the process of charging and discharging, the interface membrane, lithium dendrite will pierce the diaphragm, once replaced by a solid electrolyte, it will fundamentally solve these problems, thereby greatly improving the service life. Also, the electrolyte is solid rather than liquid, making the shape of the battery pack no longer limited and better resistant to temperature changes.
So, solid-state batteries are good everywhere, why not vigorously promote it?
Solid-state batteries are not practical at this stage
Once the electrolyte is changed from liquid to solid, the contact between the electrolyte and the electrode material changes from "liquid-solid contact" to "solid-solid contact". Because the liquid can more fully envelop the solid, this means that the effective contact area between the electrode and the electrolyte is reduced, and the efficiency of lithium ion transmission is reduced. Studies have shown that the conduction efficiency of solid electrolytes is more than 10 times lower than that of liquid electrolytes, which must not be tolerated.
If you think about it, sometimes you press the accelerator and need the battery to output a high power, but at this time, the electrolyte conduction efficiency cannot keep up, and it is easy to have insufficient power supply. Even if the solid-state battery has so many advantages, it will be "vetoed by one vote". Of course, in the long run, the defect of low conductivity of solid-state batteries can be technically overcome.
Looking at the industry, solid-state battery technology is still in the research and development stage, has not formed a mature industrial chain, the product cost is high, the process needs to be improved, and it does not meet the conditions of large-scale mass production and commercial popularization.
Solid-state batteries are promising
Nowadays, solid batteries have been clearly defined as alternatives and upgraded versions of traditional lithium batteries, and governments and major car companies are also actively deploying. Among them, Toyota, Panasonic and other companies and several universities in Japan jointly develop sulfide solid-state batteries, it is expected that by 2025 and 2030, the penetration rate of sulfide solid-state batteries in the Japanese automobile market will reach 50% and 95%, respectively, Toyota has more than a thousand solid-state battery-related patents, walking in the forefront of the industry.
Recently, China's "New Energy Vehicle Industry Development Plan" clear solid-state battery as a national strategic research direction, research and development work mainly rely on the Chinese Academy of Sciences, Ningde times, BYD and other major battery manufacturers are also actively following up. In addition, the commercial prospects for solid-state batteries are very impressive. The research report released by SNE Researchd, a well-known business consulting company, pointed out that by 2025, the global solid-state battery market is expected to reach 6 billion yuan, the Chinese market will occupy half of the country, and the global solid-state battery demand is expected to be close to 500GWh in 2030, becoming the mainstream battery on the future electric vehicle.
According to Weilai's plan, a semi-solid-state battery with a capacity of 150kWh will be installed on the ET7 model in the third quarter of 2022, helping the car NEDC to break through 1000km. In the face of media doubts, Weilai immediately clarified that it is a "semi-solid battery", and the battery still needs electrolyte and diaphragm. Uncle Che believes that the commercialization of solid-state batteries with attractive battery life and reassuring safety will advance faster than we think.
Uncle Che concluded
It can be said that the technical route of solid-state batteries is completely correct and more landed than hydrogen fuel cells. Among them, the technical obstacles are by no means unbreakable, please give enough time to researchers. After all, the commercial demand for solid-state batteries is strong, and it has also been recognized and supported by all sectors of society, and it is almost a "must-succeed" project. Uncle Che expects that at the beginning of the promotion stage, the cost of solid-state batteries is high, resulting in a high price of the vehicle, and some consumers will pay for it, and its market proportion will have a climbing process.
Today Uncle Che will talk to everyone here, welcome to leave a message in the comment area, exchange and discuss together.