Analysis of the status quo of solid state batteries: the winds have formed.

The upgrading of batteries is of obvious importance to the new energy car industry. Batteries account for half of the total vehicle cost only in terms of the most important costs in the market. The technology of other parts and components of new energy vehicles has matured. It is almost impossible to reduce the cost significantly. If you want to reduce the price to gain market advantage, you have to find a way on the battery. Who has mastered new energy vehicles.

Solid-state battery becomes a breakthrough choice

The importance of battery upgrades for the new energy automotive industry is self-evident, with batteries accounting for half of the cost of the entire vehicle, only in terms of the most costly market. The other parts and components of new energy vehicles have matured. It is almost impossible to reduce the cost accordingly. If you want to lower the price to gain market advantage, you have to find a way on the battery. You can say who has mastered the battery. Who will master the new energy vehicle. In the development of many battery technologies, solid-state batteries are regarded as the next vent, and many companies have invested in research and development, hoping to achieve breakthroughs.

Not long ago, the Ministry of Finance, the Ministry of Science and Technology, the Ministry of Industry and Information Technology, and the Development and Reform Commission jointly issued the Notice on Adjusting the Financial Subsidy Policy for the Promotion and Application of New Energy Vehicles, which clearly stipulated the power battery subsidy to increase the quality of the power battery system. The energy density requirement is not less than 90 wh / kg, and is subsidized by 1.1 times above 120 wh / kg.

In the "Promoting power battery Industry Development Action Plan" issued by the four ministries and commissions, it is clear that by 2020, the lithium-ion power battery cell should reach 300 wh / kg, which is not easy for the power battery, and Solid state battery technology is likely to be one of the few promising solutions.

Analysis of advantages and disadvantages of solid state batteries

There are many articles in the front that have mentioned the advantages and disadvantages of solid-state batteries. I will explain them briefly here.

Advantage:

1. High security performance. Safety is of the utmost importance, and solid-state batteries alone have a big advantage. So why is the safety of the solid-state battery high? Because the liquid electrolyte is short-circuited, the temperature rises and the electrolyte ignites and explodes. However, the solid electrolyte is non-flammable, non-corrosive, non-volatile, and has no leakage problems.

2. High energy density. The high energy density is mainly due to the fact that solid electrolytes generally have a wide electrochemical window, just like a small frame, so more high voltage cathode materials can be installed. In addition, the solid-state battery is small and stable, which can simplify battery management and greatly increase energy density.

3. is relatively light. In traditional lithium-ion batteries, the diaphragm and electrolyte add up to nearly 40% of the volume and 25% of the mass of the battery, while the use of solid electrolyte naturally reduces volume and mass.

4. the cycle performance is strong. The solid electrolyte solves the problem of the solid electrolyte interface film formed during the charging and discharging process of the liquid electrolyte and the lithium dendrite phenomenon, which greatly improves the cycle and service life of the lithium battery.

Disadvantages:

1. the interface impedance is too large. The interface between the solid electrolyte and the electrode material is in a solid-solid state, so the effective contact between the electrode and the electrolyte is weak, and the transport kinetics of ions in the solid matter is low.

2. fast charge is more difficult. The impedance, conductivity and other problems of the battery show that the internal resistance is large, which will hinder the charging of electricity, and because of the large internal resistance, energy loss will occur during the charging process. This part of energy waste cannot be ignored.

3. The cost price is high. Cost is the biggest factor preventing commercialization. Without profit, there is no market. The solid-state battery preparation process is not mature enough, and battery usage data collection is not comprehensive. Only in the electrolyte manufacturing of all-solid-state batteries, the technical immaturity of the two core problems of solid-solid interface optimization is enough to make the cost of solid-state batteries high.

Research progress in solid state batteries

Not long ago, the reporter learned from the Qingdao Science and Technology Bureau that the Qingdao Key Laboratory of Solar Energy and energy storage Technology, based on the Qingdao Institute of Energy and Process Technology of the Chinese Academy of Sciences, innovatively proposed the design concept of “rigid and flexible” polymer electrolytes. A composite electrolyte material system was prepared to prepare a series of solid polymer electrolyte systems with excellent comprehensive performance, which effectively solved the problem that the properties of polymer electrolytes could not be balanced, and developed a new solid electrolyte key material system. It is reported that the solid-state lithium battery developed by the laboratory has passed the third-party testing of the 8,000-meter and 11,000-meter pressure chambers of the National Deep Sea Base Management Center.

Guo Yuguo, a researcher at the Key Laboratory of Molecular Nanostructures and Nanotechnology Institute of the Institute of Chemistry, Chinese Academy of Sciences, has made progress in the research of lithium metal anodes, solid electrolytes and solid-state batteries. The researchers proposed and developed an in-situ treatment technology to successfully form a lithium phosphate solid electrolyte interface film with high Young's modulus and fast lithium ion transport capacity on the surface of metallic lithium, effectively reducing the lithium metal and electrolyte. The reaction inhibits the growth of lithium dendrites, achieves uniform regulation of the metal lithium/electrolyte interface, effectively controls the growth of metal lithium dendrites on the surface of the carbon spheres, and greatly improves the utilization of lithium, under the condition that the anode capacity is only 5% excess. The battery can still be stably cycled for a long time.

In August 2017, researchers from Hitachi, Japan, announced that their solid-state battery technology has been developed. Hitachi is working with an undisclosed Japanese battery manufacturer to refine some of the details and put the solid-state battery on the market by 2020.

In June 2017, a solid-state battery patent application numbered 20170179545 submitted by Toyota to the United States was published. Studies have shown that the solid state battery is composed of a sulfurized solid electrolyte and an electrode active material, wherein the composition of the electrolyte material includes four elements such as lithium, phosphorus, sulfur and iodine; and the positive electrode material contains a phosphate ester. The weight ratio of the phosphate in the positive electrode material ranges from 1 to 30%. The thermal stability of the solid state lithium battery is improved by adding a phosphate ester to the positive electrode material. In July, Toyota said it plans to begin selling electric vehicles powered by all-solid-state batteries in 2022.

Guo Yongsheng, R&D manager of Ningde Times, said that Ningde era is actively deploying the next generation technology of power battery, and has invested more in the research and development of solid-state lithium batteries, and is also developing the manufacturing process of solid-state batteries.

The era of solid-state batteries has arrived

Solid-state batteries are not really new things. As early as 2010, Toyota has been quietly exploring the field of solid-state batteries. However, it has not improved, until the solid-state battery patent submitted to the US Patent Office in December 2016 was finally approved, and it was a blockbuster, winning the headlines of the major pages. Academician Chen Liquan of the Chinese Academy of Engineering also said that if the entire solid-state battery is not yet deployed, it will miss the opportunity for development.

Dr. Sun Liqing, member of the National Engineering Laboratory of Electric Vehicles of Beijing Institute of Technology, and member of the Electric Vehicles Committee of the China Electrotechnical Society, said that solid electrolyte batteries will be the next outlet and the main development trend of new energy batteries in the future.

According to Wang Yan, a postdoctoral fellow at MIT, and Gebulande·saidaer, a professor of materials and engineering,solid electrolytes will become "real game changers" and will create the perfect battery -- solid electrolyte batteries,solve most of the problems facing lithium-ion batteries, so that the best balance between battery life, safety and cost.

The page contains the contents of the machine translation.