Slight Talking about Solid State Battery
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A solid-state battery is a battery that uses solid electrodes and a solid electrolyte. Solid-state batteries generally have low power density and high energy density, which is an ideal battery for electric vehicles.
In 2030, lithium-ion batteries may no longer be the mainstream of electric vehicle batteries, but they still have a place in some electronic components. According to estimates, China’s solid-state battery market is expected to reach 3 billion CNY in 2025 and 20 billion CNY in 2030.
Since Sony introduced lithium-ion batteries containing liquid electrolytes into electronic devices in 1991, liquid lithium batteries have become one of the most mature and widely used technical routes.
In 2010, Toyota launched a solid-state battery with a cruising range of more than 1000KM. Efforts including QuantumScape and Sakti3 are also trying to replace traditional liquid lithium batteries with solid-state batteries.
Canadian company Avestor also tried to develop solid-state lithium batteries, and finally filed for bankruptcy in 2006. Avestor uses a polymer separator to replace the liquid electrolyte in the battery, but has not solved the safety problem, and there have been several battery fires or explosions in North America.
In mid-March 2015, James Dyson, the inventor of the vacuum cleaner and the founder of the British company Dyson, invested his first $15 million in solid-state battery company Sakti3, which is a battery startup founded in 2007.
In January 2018, a breakthrough new battery technology seems to be finally close to reality. If expected, the new technology could keep mobile phone addicts going for days and increase the range of electric vehicles to more than about 800 kilometers. The new technology, known as solid-state battery technology, replaces the liquid electrolytes in today’s batteries with ceramic materials.
In January 2018, it formed an alliance with BMW, which has pledged to supply some form of battery component to every product it makes for the next 10 years.
On January 9, 2021, Weilai Automobile released a new 150kWh solid-state battery pack. The Weilai electric vehicle equipped with this technology is expected to be delivered in the fourth quarter of 2022, and the cruising range is expected to exceed 1,000 kilometers.
On January 22, 2022, the Dongfeng E70 demonstration operating vehicle equipped with Ganfeng solid-state batteries was launched in Xinyu, and the first batch of 50 solid-state battery demonstration operating vehicles was officially launched on the market. The first production line of the new lithium battery project with an annual output of 10GWh in the second phase of Ganfeng Lithium Battery was also officially put into operation on the same day.
The traditional liquid lithium battery is also vividly called a “rocking chair battery” by scientists. The two ends of the rocking chair are the positive and negative poles of the battery, and the electrolyte (liquid) is in the middle. The lithium ion is like an excellent athlete, running back and forth at both ends of the rocking chair. During the movement of the lithium ion from the positive electrode to the negative electrode and then to the positive electrode, the charging and discharging process of the battery is completed.
The principle of a solid-state battery is the same, except that its electrolyte is solid, and its density and structure allow more charged ions to gather at one end, conduct greater current, and increase battery capacity. Therefore, for the same amount of power, the volume of solid-state batteries will become smaller. Not only that, since there is no liquid electrolyte in solid-state batteries, storage will become easier, when used on large equipment such as automobiles, there is no need to add additional cooling pipes, electronic controls, etc., which not only saves costs, but also effectively reduces weight.
- Light – high energy density. After using all-solid-state electrolytes, the applicable material system of lithium-ion batteries will also change. The core point is that it is not necessary to use lithium-intercalated graphite negative electrodes, but directly use metal lithium as negative electrodes, which can significantly reduce the amount of negative electrode materials, so that the energy density of the entire battery can be significantly improved.
- Thin – small in size. In traditional lithium-ion batteries, separators and electrolytes are required, which together account for nearly 40% of the volume and 25% of the mass of the battery. And if they are replaced by solid electrolytes (mainly organic and inorganic ceramic materials), the distance between the positive and negative electrodes (traditionally filled by diaphragm electrolyte, now filled by solid electrolyte) can be shortened to only a few microns to a dozen microns, so that the thickness of the battery can be greatly reduced, so all-solid-state battery technology is the only way for the miniaturization and thinning of batteries.
- The prospect of flexibility. Even brittle ceramic materials are often bendable at sub-millimeter thicknesses, and the material becomes flexible. Correspondingly, the flexibility of all-solid-state batteries will also be significantly improved after being thinner and thinner. By using appropriate encapsulation materials (not a rigid casing), the fabricated battery can withstand hundreds to thousands of bends without substantially degrading its performance.
- Safer. The following dangers may occur in traditional lithium batteries:
(1) Lithium dendrites may appear when working under high current, which will puncture the diaphragm and cause short circuit damage
(2) The electrolyte is an organic liquid, which tends to intensify side reactions, oxidative decomposition, gas generation, and combustion at high temperatures.
Using all-solid-state battery technology, the above two problems can be directly solved
“Solid-state batteries may be one of the future directions of battery technology, but maybe not the best.”A technician from a new energy production company said, “Including fuel cells, supercapacitors, aluminum-air batteries, and magnesium batteries, there is a lot of room for development in concept, and in the end, it depends on which route develops faster and is more down-to-earth.” The so-called down-to-earth means that a perfect balance can be achieved in terms of commercialization scale and cost. First, the materials used must not be expensive and rare. Secondly, it is possible to realize large-scale application in various industries and fields.
Perhaps, the most testing place now is the price, the cost of a liquid lithium battery is about $200-300/kWh. If you use existing technology to make a solid-state battery that is enough to power a smartphone, the cost will reach $15,000, and the cost of a solid-state battery that is enough to power a car reaches staggering $90 million. Sastry said that an important reason for the high production cost of solid-state batteries is the low production efficiency. According to Sastry’s plan, Sakti3 will eventually reduce the cost of the battery to $100/kWh, but she did not give the final time.
Judging from the time when the theory was proposed, solid-state batteries are not a new concept, but over the years, the progress in research and development has not been as fast as imagined. A technician from South Korea’s Samsung believes that even if Sakti3 can finally reduce the cost, it will take a long time for the battery to go from the laboratory to the final mass production. Just like liquid lithium batteries, in the 1970s, related concepts and experimental certifications were advancing hand in hand, but the real large-scale use was already at the end of the 20th century.