The development of new energy vehicles is the only way for my country to move from a big automobile country to a powerful automobile country. It is a strategic measure to promote green development and an effective measure to achieve "carbon neutrality". With the development of new energy vehicles, people pay more and more attention to the safety performance of new energy vehicles. Silica aerogels are considered to have excellent fire-retardant and flame-retardant, soft impact resistance, sound insulation and noise reduction functions, and can be used in new energy vehicle power systems to better achieve battery temperature control and electronic control management and improve performance. It is currently a thinner and more efficient thermal insulation material suitable for new energy vehicles and power lithium batteries.

Applications

Single cell silica aerogel thermal insulation protection

The thermal protection between the cells is to add a thermal insulation layer between the cells to block the propagation of thermal runaway from the uncontrolled single cell to the surrounding cells, reducing the damage to the battery pack and the accompanying damage. Silica aerogel materials have low thermal conductivity, excellent fire resistance and waterproof performance, small footprint, long life, and no pollution to the environment, making them the best thermal insulation materials for automotive batteries. At the same time, the performance of the electric vehicle is greatly affected by the temperature. If the temperature is too low, the performance of the regenerative braking system will be affected. The charging speed will be too slow and the battery will not be fully charged. Silica aerogel can also ensure that the battery temperature will not be too low.

Thermal insulation principle of aerogel in batteries

In addition, due to its excellent thermal insulation and flame retardant properties, silica aerogel can further reduce the safety distance between monomers. In order to save more space and improve the total power of the battery pack, silica aerogel companies have developed a series of high-performance ultra-thin aerogel insulation boards, insulation paper and other products to meet the needs of the battery industry for safety and high energy density.

The solution of Tesla, CATL, SAIC-GM, Yutong and other companies is to place silica aerogel between the cells.

In its patent for lithium-ion battery packs in cars, Tesla has designed a separator made of a composite of thermal insulation and elastic materials, which is placed between cells in different columns of a battery module to block adjacent cells. thermal runaway spread between. In "Research on Thermal Protection and Heat Dissipation Integration of Vehicle Power Batteries", a heat shield with a thermal conductivity of about 0.020W/(m·K) was used to establish a battery pack simulation model with a square ternary lithium-ion battery as the object. The integrated thermal management scheme of alternately placing heat shields and heat pipes in the battery pack can not only improve the heat dissipation capacity of the battery pack, improve the uniformity of temperature distribution inside the battery pack, but also greatly prolong the propagation time of thermal runaway and improve the safety performance of the battery pack. . Secondly, increasing the thickness of the heat shield from 1mm to 2mm can also completely block the propagation of thermal runaway.

Comparison of monomer temperature and blank group monomer temperature curve

According to the introduction of SAIC-GM, the company added nano-scale aerogel between the cells of the pure electric MAV Buick Micro Blue, which is the high battery energy density of 140Wh/kg and the low energy consumption of 13.1kW h for the Buick Micro Blue 410KM version. The contribution has strengthened the safety of the Buick MicroBlue battery pack and laid the foundation for the high-voltage system of the Buick MicroBlue to meet the system safety ASILD (Automotive Safety Level Highest Level) standard.

Battery pack/box overall protection

Thermal runaway accidents of lithium-ion power battery packs occur from time to time. The thermal runaway protection of lithium-ion power battery systems requires thermal protection not only between battery cells, between battery modules, and between battery boxes and passenger compartments to avoid thermal runaway. Improve the thermal resistance of the thermal runaway cell to transfer heat to other systems of the battery, so as to prevent the spread of thermal runaway. In addition to excellent heat insulation, fire resistance and flame retardant properties, aerogel felt also has the properties of softness, arbitrary cutting and processing. It can be used for thermal protection between battery modules of various shapes, battery boxes and passenger compartments.

Market size forecast

As the market price of silica aerogel materials continues to decline, in the field of industrial thermal insulation, the total project cost of using aerogel materials is close to that of traditional thermal insulation materials. Sino Energy predicts that the inflection point of the rapid development of silica aerogel has actually come quietly, and the silica aerogel industry as a whole has entered an explosive growth stage. Materials, in the next 5-10 years, may reach the scale of 1.9-17 billion US dollars per year. With the maturity of the aerogel material process and the expansion of the production scale, the application and market penetration in the power battery of new energy vehicles will also surge with the growth of the new energy vehicle industry.