What is aerogel?

Silica Aerogel is a form of solid matter, the least dense solid in the world. The density is 3 kilograms per cubic meter. The most common aerogel is silica aerogel, which was first made by American scientist Kistler in 1931 as a result of a bet with his friends. There are many types of silica aerogels, including silicon-based, carbon-based, sulfur-based, metal oxide-based, metal-based and so on. aerogel is a compound word, where aero is an adjective, which means flying, and gel is obviously a gel. Literally a gel that can fly. Any gel of any substance can be called silica aerogel as long as it can be dried to remove the internal solvent, and its shape can remain basically unchanged, and the product has high porosity and low density.

Why is silica aerogel so important to the new energy industry chain?

1. Silica Aerogel is used for thermal runaway thermal insulation of ternary batteries

You can often see videos of electric vehicles spontaneously combusting. It often takes only a few seconds from the fire to the deflagration of the whole vehicle. The main reason is that the internal insulation level of the battery is not enough, and the thermal failure of a single cell extends to the entire battery pack.

The Ministry of Industry and Information Technology issued the "Safety Requirements for Power Batteries for Electric Vehicles", adding a thermal diffusion test of the battery system, requiring that after the thermal runaway of the battery cell occurs, the battery system does not catch fire and does not explode within 5 minutes, so as to reserve safe escape time for the occupants. This requirement will come into effect on January 1, 2021.

The biggest role of fire and heat insulation materials is to delay or prevent the spread of heat and the spread of flames, leaving enough time for passengers to evacuate the accident scene.
Battery factories or OEMs generally use fire-proof and heat-insulating materials between the cells and the upper cover of the module and PACK. Aerogel has low thermal conductivity, good thermal insulation effect, and non-combustibility. Compared with traditional thermal insulation materials, only 1/5-1/3 of the thickness can achieve the same thermal insulation effect, saving more space for power batteries, and the thermal insulation effect is better than that of traditional thermal insulation materials. temperature is more stable.

The application in new energy vehicles can better realize the temperature control and electronic control management of the battery and improve the performance, play the role of heat insulation and fire prevention, and buy more time for users and passengers to escape the scene and put out the fire.

2. Silica Aerogel is used for lithium iron phosphate battery insulation in winter

In the low temperature environment of lithium iron phosphate battery, the movement ability of charged electrons in the positive and negative electrode materials becomes poor, resulting in the decline of battery capacity and the reduction of battery life. The excellent thermal insulation performance of aerogel can make the cells in the lithium iron phosphate battery not affected by the external low temperature.

BYD battery modules use silica aerogel for isolation:

3. Silica Aerogel is an important component of solid-state battery polymer electrolyte
Using silica aerogels as the backbone of polymer-based electrolytes, a super-strength reinforced composite polymer electrolyte for solid-state batteries was successfully designed and fabricated.

This novel composite electrolyte consists of an interconnected SiO₂ silica aerogel framework and a highly conductive cross-linked PEO-based electrolyte. The interconnected SiO₂ silica aerogels not only act as strong pillars to strengthen the entire composite, but also provide a large and continuous surface for strong anion adsorption, resulting in a highly conductive pathway through the composite

4. Application advantages of silica aerogel in the field of automobiles and power batteries
Mainly, it has the best heat insulation effect per unit volume, flame retardant, stable performance and thermal shrinkage. Meets extremely high safety requirements.

In terms of solving the thermal runaway diffusion of lithium iron phosphate battery in low temperature environment and the thermal runaway diffusion of ternary battery in high temperature environment, silica aerogel has been recognized by the two key battery routes, and it is the preferred material for lithium battery thermal insulation.
According to AspenAerogel's 19th annual report, the average price of silica aerogel materials in recent years is about 30 US dollars / square meter, and each new energy vehicle needs about 2-5 square meters of silica aerogel composite materials, so the average value of each new energy vehicle is 105 Dollars of Aerogel Composites.

According to the requirements of the "New Energy Vehicle Industry Development Plan (2021-2035)", by 2025, the sales of new energy vehicles will reach about 20% of the total sales of new vehicles. The planned annual compound growth rate must reach more than 30%.

It is estimated that the potential scale of aerogel composite materials in the global new energy vehicle market is about 1.575 billion US dollars in 2025, and will reach 3.150 billion US dollars in 2030.

The picture shows the aerogel products used by SAIC-GM:

Policies promote the vigorous development of aerogels

1. The demand for high-standard thermal insulation and flame retardant drives a new round of aerogel industrialization

On the evening of October 24, 2022, the "Opinions of the Central Committee of the Communist Party of China and the State Council on Completely, Accurately and Comprehensively Implementing the New Development Concept and Doing a Good Job in Carbon Neutralization" was officially released. Article 21 of the document calls for accelerating the research and development and promotion of advanced applicable technologies.

Top-level policies for the two-carbon work have made clear the push for silica aerogel applications.
Traditional heat-insulating and flame-retardant materials include rock wool, mica, foamed materials, glass fiber, etc., each of which has constraints, such as large thickness (low heat-insulating performance per unit thickness), non-flame retardant, debris harmful to human body, easy to use. loose etc.

In high-standard scenarios with high thermal insulation performance, high flame retardant requirements, and high mechanical performance requirements (power battery thermal insulation, dense chemical pipelines), only aerogel can meet the requirements.

The generation of new demands drives a new round of industrialization of silica aerogels.

Thermal insulation principle of silica aerogel in battery:

2. Intensive introduction of policy standards to accelerate the rapid penetration of silica aerogels
Due to the energy-saving and safety features of silica aerogel, policies and standards have been introduced intensively under the catalysis of the outbreak of industrial demand.

There are not only the "Opinions of the Central Committee of the Communist Party of China and the State Council on Completely, Accurately and Comprehensively Implementing the New Development Concept and Doing a Good Job in Carbon Neutralization" at the central level, but also the "Safety Requirements for Power Batteries for Electric Vehicles" at the national standard level, etc. The promotion of gel in lithium battery, energy chemical industry, green building and other fields.

The "Silica Aerogel Heat Insulation Sheets for Lithium-ion Power Batteries" co-edited by BYD, Yiwei Lithium Energy and other battery companies clarifies the technical standards of aerogels and accelerates the use of silica aerogels in the whole industry.