In recent years, with the continuous increase in the number of new energy vehicles in China, the frequency of fire accidents related to them has also been increasing year by year. According to data released by the Ministry of Emergency Management, there will be an average of 7 new energy vehicle fire accidents per day in 2022. The safety issues of new energy vehicles pose a serious threat to the life and property safety of drivers, and the corresponding solutions to the "spontaneous combustion" of cars have become an increasingly concerned topic.
Since 2021, China has been assessing the safety of lithium batteries at the system level, and selecting high-quality insulation materials has become the mainstream choice for most car companies and battery factories. The "Safety Requirements for Power Batteries for Electric Vehicles" officially implemented on January 1, 2021, will focus on the safety of lithium battery systems and add a system thermal diffusion test, requiring that the battery system should not ignite or explode within 5 minutes after thermal runaway of a battery cell. In order to achieve the "5min safe escape time", it is necessary to improve the thermal insulation material of the battery pack to delay the explosion time of the faulty battery pack. Aerogel is just a material with excellent insulation, heat insulation and flame retardant effects at the same time.
The solidified smoke
Widely applicable in various fields
As a "magic material that can change the world", aerogel is a solid thermal insulation material with the lowest thermal conductivity and density known at present, known as "solidified smoke" and "blue smoke". It is also a national basic strategic frontier new material, which is of great strategic significance to reduce carbon emissions and achieve the goal of "double carbon".
The fire and heat insulation of gel mainly comes from its special structure. We can understand aerogel as a nano version of porous sponge. Its pore diameter is basically a microporous diameter of 20-50 nm, and the size of the air molecule is about 70 nm, which is larger than the diameter of the pores of the aerogel material. Therefore, the air flow efficiency on the aerogel is extremely low, and the thermal insulation performance is very good.
In recent years, in order to promote the development of the aerogel industry, China has successively issued many policies, such as the Guiding Opinions on Promoting the High Quality Development of Central Enterprises and Doing a Good Job in Carbon Peak and Carbon Neutralization issued by the General Office of the State Council in 2021, which encourages the strengthening of research on common basic technologies in the industry, and accelerating the research and application of carbon fiber, aerogel and other new materials.
Relevant policies of national aerogel industry
Why develop aerogel?
To answer this question, we first need the application field of antiaerosive gel.
Aerogel is widely used downstream, with thermal insulation as the leading factor. It was initially widely used in high-end technology fields such as aerospace and military industry. Aerogel gel was used as thermal insulation protection material for the U.S. "Mars Pathfinder" carrier rocket, Russia's "Peace" space station, "China Space Station", "Shenzhou Manned Spacecraft", "Zhurong Mars Rover", and "Long March Series Rocket".
With the transformation and upgrading of China's economy and the implementation of the national nano material strategy, the aerogel with outstanding thermal insulation performance and mature technology has achieved industrialization in China, and is gradually moving towards the civil market. For example, in order to maintain the fluidity of oil during oil exploitation, pipeline insulation is required. If the outer layer of oil pipeline is wrapped with aerogel, only 2cm thick, insulation can be achieved during transportation and energy loss can be reduced.
In addition, aerogel also plays a "firewall" role in new energy vehicle batteries.
On the one hand, the air gel is filled between the electric core and the electric core, and insulation, heat insulation and flame retardancy play their respective roles at the same time. Even if individual electric cores are out of control, the heat dissipation system can quickly control the temperature below the ignition point, effectively control the heat loss, and the battery pack will not be easily "ignited"; Even if a battery cell is "ignited", due to the strong thermal insulation and flame retardant protection properties of the material surrounding the battery cell, it can withstand the instantaneous impact of high temperature energy caused by flames, control the spread of combustion, and will not have a chain reaction "implicating" other battery cells in the battery, thus fighting for longer escape time for car drivers and passengers. On the other hand, in the cold winter, because the aerogel has an excellent thermal insulation effect on the battery cell, it can also prevent the battery's endurance from decreasing due to the too cold weather.
At present, the application fields of aerogel are mainly concentrated in industrial pipeline insulation, new energy vehicles, daily outdoor insulation, etc. With the continuous expansion of application fields, the market for building construction will also gradually open. Therefore, the development of aerogel is an inevitable result under the dual influence of policy orientation and industry demand.
Demand turning point upwards
Targeting the billion dollar blue ocean market
In recent years, the global aerogel market demand has been growing. According to the research data of Wanchuang Research Institute, it is optimistic that by 2025, the global aerogel product market size will exceed 39 billion yuan, and China's aerogel product market size will exceed 21.4 billion yuan.
The core reason for the rapid expansion of the scale of the aerogel track lies in the new growth point of the new energy vehicle market - the requirement of power battery safety.
Fire prevention and heat insulation is the core value of aerogel products. In the power battery industry, this heat insulation value is further extended to the "safety" value, thus opening the road of rapid growth of aerogel track.
The overall development trend of power batteries is towards increasing battery energy density and higher battery safety performance. The increase in energy density requires a smaller volume and lighter weight of the battery at the same level of charge. However, the higher the energy density, the more unsafe the battery becomes, making it more prone to fire and explosion. Due to its unique structure, aerogel can just adjust the contradiction in the development of power battery. It can be used in new energy vehicles to reduce the risk of combustion and explosion, improve its low-temperature performance, and extend the service life of the battery pack.
In addition to power batteries, aerogels can also be applied to the whole vehicle structure of automobiles, such as roof, door frame, hood, etc., which can achieve the effect of heat preservation, energy conservation and emission reduction in the compartment. In addition, compared with ordinary materials, aerogels can significantly reduce the space occupied in the vehicle.
Although the aero gel track is gradually hot, the permeability of aero gel in China is generally low.
There are two main reasons: first, the current price of aerogel is higher than that of traditional materials. In the future, with the large-scale mass production of aerogel enterprises and the optimization of process routes, the downward exploration elasticity of comprehensive costs is greater.
In terms of technology, the atmospheric drying process in China has gradually improved, and is gradually replacing the high cost and long cycle supercritical preparation process. The manufacturing cost can be reduced to 1/20 of the supercritical process. However, the atmospheric drying process is still not perfect at present, and the quality and performance of the prepared products are poor. Most products are suitable for the large pipeline level aerogel market. In addition, in the preparation process of aerogel, enterprises can also use fiber composite to reduce the comprehensive cost and improve the mechanical strength. There are three mainstream media of domestic aerogel: pre oxygen wire, ceramic fiber and glass fiber.
Second, at present, most manufacturers in the aerogel material die-cutting industry of the power battery industry need to improve their degree of automation. Automatic production is a major trend and an important cost reduction method.
As for the future development trend of aerogel industry, the core development trend of basic materials can be roughly divided into two steps. The first step is to find a relatively fast expanding market, and the second step is to find a relatively large market.
For gel, the market for new energy vehicles and power batteries is the key scene of its rapid expansion, while fields such as building insulation materials are the next 100 billion level alternative market for gel.
At present, the overall scale of the thermal insulation materials used in the construction market in China is huge, and the types are rich, such as the coating for the exterior floor of buildings, foam boards. The thermal conductivity and combustion grade of aerogel composite products are both dominant. Aerogel gel can be thinner to achieve better thermal insulation effect, and can also effectively increase the usable area of the house. With the continuous growth of raw material capacity and the help of cost reduction measures, gel is expected to accelerate the replacement of traditional thermal insulation materials by virtue of its excellent performance and thin structure, and be applied in more fields, and the market size of gel will continue to expand.
In fact, gel products are not only supply chain products, but also general materials serving various industries. Aerogel materials not only have commercial value, but also have strong social value. Their application fields are related to the national economy and people's livelihood. From this point of view, the attention of gel to the capital market is just the beginning. Some investors also said that the future growth value of gel is immeasurable and deserves continuous attention.
At present, the large-scale industrialization of silica aerogels in the market is silica aerogels. Its upstream is silicon sources (which can be divided into organic and inorganic according to different sources). After preparation, aerogels are made into aerogels (which can be divided into supercritical and normal pressure according to different drying processes). Aerogels are generally not directly used, but made into aerogel products (aerogel felt, aerogel plate, aerogel gel insulation blanket, etc.); Finally, it is applied to multiple downstream industries such as petrochemicals, building materials, new energy vehicles, aerospace and military industries.
Upstream: Raw material silicon
The main raw material upstream of aerogel is silicon, which can be divided into organic silicon source (mainstream) and inorganic silicon source.
Organic silicon source: The main raw materials are methyl orthosilicate and ethyl orthosilicate (belonging to functional silane). Organic silicon source is currently the mainstream route due to its simple post-treatment and superior performance.
Inorganic silicon source: inorganic compounds such as water glass. Its upstream is the polysilicon industry.
Middle stream: aerogel production
The performance of gel is mainly determined by its nano pore structure. Generally, the required nano pores and the corresponding gel skeleton are obtained through the sol gel process. Because the solvent inside the gel skeleton has surface tension, the skeleton will collapse under ordinary drying conditions. The core of aerogel preparation technology is to avoid the collapse of nano pore structure due to capillary force during drying. After the production of gel, the aerogel material manufacturer does not sell the aerogel directly, but makes products (aerogel felt, etc.), which are generally sold by pieces.
According to different drying processes, the preparation process of aerogel can be divided into supercritical drying process and atmospheric drying process:
Supercritical: Good performance, high growth, and mature development. Supercritical technology is the earliest technology to realize batch preparation of aerogel, which is relatively mature, and is also the technology adopted by domestic and foreign aerogel enterprises. At present, batch production technology generally uses carbon dioxide as the drying medium, abbreviated as carbon dioxide supercritical drying technology.
Atmospheric pressure drying: Low cost but difficult to achieve good performance, few factories have spare parts. A new type of aerogel preparation process is currently the most active research and development potential of aerogel mass production technology.
Downstream: packaging of aerogel products
Aerogel products made by the above production enterprises often need to be compounded with other materials (aerogel materials have low strength and high brittleness, and their direct use is limited, so they are usually compounded with organic polymers and fiber reinforced materials) and packaged before they can be used in downstream (battery plants, car plants).