How to solve the problem of driving distance and safety of power lithium battery?

On the evening of April 21, a Tesla ModelS electric car in the underground parking garage of a community in Shanghai suddenly ignited and ignited several cars parked next to it. The scene of the incident in the video was shocking. Less than 24 hours later, a Weilai ES8 electric car in Xi'an ignited spontaneously. On April 24, a BYD E5 electric car in Wuhan also ignited spontaneously. A series of spontaneous combustion has caused people to mostly point to the power lithium battery. At this stage, the data system of the new power passenger car battery is mainly the ternary positive electrode-liquid electrolyte-graphite negative electrode. The battery using the lithium iron phosphate positive electrode is mainly used in the field of special vehicles such as buses and logistics. From the data of vehicle batteries in 2018 , The ternary system battery accounts for nearly 60%. Fu Zhengwen, a professor of chemistry at Fudan University and a doctoral supervisor, analyzed in an interview with a reporter from my country Car News that there is no combustible liquid organic solution in solid-state batteries, and the safety factor has improved a lot. Solving the problem of driving distance and safety of the power lithium battery of the new power car has naturally become the top priority. The all-solid-state lithium-ion battery is a kind of lithium-ion battery that uses solid electrode materials and solid electrolyte materials and does not contain any liquid. It mainly contains all-solid-state lithium-ion batteries and all-solid-state metal lithium-ion batteries. The difference is that the former does not contain metal in the negative electrode. Lithium, the negative electrode of the latter is metallic lithium. Among the various new battery systems at present, solid-state batteries use new solid electrolytes to replace the current organic electrolytes and barriers, which have high safety and high volume energy density. At the same time, they are compatible with different new high-energy electrode systems (such as lithium-sulfur systems, metal- Air system, etc.) has a wide range of adaptability, which can further improve the quality and energy density, and increase the driving ability while improving the safety, which is expected to become the solution of the next generation of power lithium batteries, which has caused many research organizations and start-up companies at home and abroad. And the love of some car companies, Tianbian sedan is one of them. Solid-state batteries have distinct advantages. A few days ago, the news that a one-minute charge and an 800-kilometer drive has attracted the attention of the industry and focused people’s attention on solid-state batteries. Although this piece of news disclosed by Fisker still has much to discuss, it at least shows that solid-state batteries have distinct advantages and are expected to become a new direction for the development of lithium-ion batteries for new-powered cars. The first is a high safety function. Traditional lithium-ion batteries use organic liquid electrolyte. Under abnormal conditions such as overcharging and internal short-circuit, the battery is prone to heat, causing the electrolyte to expand, spontaneously ignite and even explode, posing serious safety hazards. Many inorganic solid electrolyte materials are non-flammable, non-corrosive, non-volatile, and have no leakage problems. Compared with liquid electrolytes containing flammable solvents, polymer solid electrolytes have greatly improved battery safety. The second is high energy density. Metal lithium can be used as the negative electrode of solid-state lithium-ion batteries. The energy density of the battery is expected to reach 300-400Wh/kg or even higher. Its electrochemical stability window can reach more than 5V, which can match high-voltage electrode materials to further improve quality. Energy density: There is no liquid electrolyte and barrier, which reduces the weight of the battery, shrinks the internal space of the battery, and improves the volumetric energy density; the safety is improved, the battery casing and cooling system modules are simplified, and the system energy density is improved. The third is the long cycle life. It is expected that the liquid electrolyte will continue to form and grow the SEI film during the charging and discharging process and the lithium dendrites pierce the barrier, which will greatly improve the cycle performance and service life of the metal lithium ion battery. The fourth is a wide range of operating temperature planning. The solid-state lithium-ion battery has excellent acupuncture and high-temperature stability. If all inorganic solid electrolytes are used, the maximum operating temperature is expected to reach 300°C, which may cause the positive and negative materials to react with the electrolyte at high temperatures. The heat is out of control.