Not long ago, the aerogel used for battery protection caught fire at the Xiaomi Auto Technology Conference. In brief, in order to ensure the safety of the battery, Xiaomi Automobile is equipped with air gel on both sides of each cell, which can play the role of heat insulation and fire prevention, and effectively protect the battery safety. Aerogel is a kind of material with excellent heat insulation and flame retardancy. This material has been widely used as heat insulation material in the aerospace field before, but the biggest problem is the high cost. The side of the cell in Xiaomi SU7 battery pack uses 165 pieces of aerogel as heat insulation material, which is full of conscience.
Aerogel is the most efficient energy-saving heat insulation material at present
With the popularization of new energy vehicles, lithium batteries have become mainstream power batteries. However, due to their high energy density, thermal runaway of batteries has attracted much attention, mainly caused by internal short circuits, overcharging, overdischarging, and high temperatures. Electric vehicles experiencing thermal runaway may lead to battery combustion, causing surrounding components to catch fire and even explode in extreme cases. To solve this problem, automobile manufacturers and battery manufacturers have turned their attention to aerogels, especially in the application of heat insulation and flame retardancy. The excellent thermal insulation and flame retardant properties of aerogel effectively reduce the risk of thermal runaway, improve the safety and stability of the battery, and become the best choice to solve the safety problems of the power battery system. At the same time, its lightweight and flame retardant properties are crucial in improving battery performance and lightweight.
Aerogel is a new generation of energy-efficient thermal insulation material. Aerogel is a kind of solid material with nano porous network structure and filled with gaseous dispersion medium in the pores. It is the lightest solid in the world. Due to its unique structure, aerogels exhibit excellent performance in many fields such as heat, acoustics, optics, electricity, mechanics, etc. At present, the commercial application of aerogels mainly focuses on their efficient heat resistance capability, and downstream applications include petrochemical industry, heat pipe network, lithium battery, building materials, outdoor clothing, aerospace, military industry and many other fields.
Compared with traditional thermal insulation materials, aerogel has the characteristics of low density (0.16Kg/m3), high porosity (80% -99.8%), large specific surface area (400-1000m2/g), and low thermal conductivity (10mW/mK).
In addition, aerogel also has good fire resistance, hydrophobicity, sound insulation, adsorption, green environmental protection and so on. Compared with traditional thermal insulation materials, aerogel has excellent thermal insulation performance. Fireproof and hydrophobic: can meet the national A1 level non combustible standard for building materials, with a hydrophobic rate of N98%; Weather resistance: the air gel insulation material is hydrophobic as a whole, difficult to absorb water and disintegrate, and its service life can reach more than 10 years, which is 3-5 times longer than that of traditional insulation materials; Sound insulation and earthquake resistance: the three-dimensional porous network structure of aerogel can play the role of sound absorption, noise reduction, and shock absorption; Health and Environmental Protection: The product has passed RoHS, REACH, and ELV testing and does not contain any harmful substances to the human body; Very ideal adsorbent material.
Compared with traditional thermal insulation materials, aerogel has better thermal insulation performance and longer service life. The ultra-low thermal conductivity of aerogel ensures its excellent thermal insulation effect. Its thermal insulation performance is 2-5 times that of traditional thermal insulation materials, and it can be used from -200 ℃ to 650 ℃. At the same time, the special structure of nano pores of aerogel makes it withstand pressure and tension, and its service life is more than 5 times that of traditional materials. The outstanding thermal insulation performance of aerogel comes from its porous structure. The pore size of aerogel is lower than the average free path of air molecules under normal pressure, so the air molecules in the pores are nearly static, thus avoiding the convection heat transfer of air. The extremely low bulk density of aerogel and the curved path of porous structure also prevent the heat conduction in gas and solid state, and the void walls tending to be "infinite" can minimize the heat radiation. The three aspects work together to block almost all heat transfer paths, making the aerogel achieve the heat insulation effect that other materials cannot match.
The preparation process of aerogel mainly includes sol gel, aging, modification and drying of wet gel. Sol gel process refers to the process of precursor sol aggregation and condensation to form gel. However, due to the insufficient three-dimensional strength of the newly formed wet gel, it is easy to break and collapse, so it is necessary to age in the parent solution for a period of time to improve the strength or use surface modification to reduce or eliminate drying stress. The drying process is to replace the solution in the pores of wet gel with air and discharge it.

The domestic aerogel market has begun to take shape in the past five years
At present, the aerogel industry has begun to take shape. We believe that the current time point will be the inflection point for the take-off of the aerogel industry, because:
1) With the maturity of carbon dioxide supercritical technology and the rapid expansion of the industry, its cost has decreased by about 80% compared to 10 years ago, and its economy is gradually improving;
2) Reducing the heat loss of high-temperature oil and gas pipelines and improving the thermal insulation efficiency of high-temperature reactors are in line with the general trend of carbon emission reduction. With excellent heat resistance, aerogel will gradually replace traditional thermal insulation materials, with broad market space;
3) New energy vehicles and energy storage lithium battery systems have high requirements for the safety of lithium batteries, so aerogels with excellent thermal resistance performance are needed as the thermal insulation materials of lithium batteries. The rapid improvement of lithium battery installation will rapidly boost the demand for aerogels.

Morever, there has been significant progress in production.
The average annual growth rate in the next 5 years will reach 63.6%
From 2015 to 2020, the average annual compound growth rate of domestic aerogel material output was 38.5%. In the past five years, the domestic aerogel market achieved a rapid jump in output and a rapid decline in cost through technological progress. The current cost has dropped by more than 80% compared with 10 years ago.
Under the current dual carbon policy, energy conservation will become the main theme of the future development of the chemical, energy and construction industries, and the aerogel industry is in the rapid development stage of turning point upward. At present, gel has a very competitive cost performance ratio in petrochemical pipelines, high-temperature reactors, heat supply network pipelines, and lithium batteries. Leading enterprises such as PetroChina and Ningde Times have switched from traditional insulation materials to aerogel. The benchmarking effect of leading enterprises will bring about the take-off of gel business.
According to Aspen's prediction, the total global market space in the next 10 years is 700 billion yuan. It is estimated that by 2025, the demand of domestic petrochemical pipelines and central heating pipelines for aerogels will reach 15.5 billion yuan, the demand of lithium batteries for aerogels will reach 2 billion yuan, and the demand of building materials for aerogels will reach 730 million yuan, with a total demand of 18.5 billion yuan. In 2020, the output value of domestic aerogel will be about 1.6 billion yuan, and the average annual growth rate will reach 63.6% in the next five years.
A number of enterprises have entered the aerogel industry to accelerate the expansion of industry capacity. At present, many listed companies have begun to lay out aerogel production capacity through equity investment in the past two years. According to our statistics, the existing domestic aerogel production capacity is about 157000 m3, while the expansion of mainstream enterprises is about 160000 m3 in total. Based on the two-year production cycle, it is expected that the industry's production capacity will double on the basis of 2021 in 2023, and the average annual growth rate of the supply side will be 50%.