Recently, an enhanced acoustic solar PVB interlayer jointly developed by Li Auto and Eastman successfully rolled off Eastman’s production line. It is the first adoption with enhanced acoustic solar technology in Li Auto. Taking this opportunity, let’s talk about the technological innovation of PVB interlayers for automotive glass.
PVB interlayers may be unfamiliar to many people. It is laminated between the glass in the car you ride in every day, helping protect your tranquility and comfort. It is the core functional material of laminated glass, directly affecting key vehicle performance aspects such as acoustics, solar control, and safety.
Recently, Li Auto, in collaboration with Eastman, a world-leading PVB interlayer supplier, officially launched the industry’s first enhanced acoustic solar PVB interlayer. This interlayer achieves both enhanced acoustic and solar performance, saving users the cost of aftermarket window tinting for front door windows, which can cost over 1,000 yuan.
What is a PVB interlayer?
Simply put, a PVB interlayer (polyvinyl butyral) is a transparent film placed in the middle of laminated glass. It is equivalent to the “core” of the glass and directly determines key performance aspects such as acoustics, solar control, and safety.
The mid- to high-end cars we drive daily use laminated glass for their side windows and windshields. The basic structure of this glass is a sandwich of “glass + PVB interlayer + glass.” The PVB interlayer, laminated between two layers of glass, not only holds broken glass together during a collision to help prevent injury, but also actively improves acoustic and solar performance through advanced formulations and innovative structures.
In traditional gasoline-powered vehicles, noise is primarily generated by the internal combustion engine. However, in the era of new energy vehicles, with engine noise disappearing, wind noise has become a significant source of noise inside the vehicle. Creating an extremely quiet environment for occupants in windy conditions is a crucial issue in the NVH (Noise, Vibration, and Harshness) design of new energy vehicles, and the PVB interlayer is a key material for solving this problem.
Meanwhile, during summer driving, near-infrared rays from the sun, especially in the 1550 nm and 1950 nm bands, can penetrate glass and reach the skin. Therefore, even with the air conditioning on, passengers may still experience noticeable discomfort under direct sunlight. This heat-related discomfort is precisely the key experience that a PVB interlayer solar innovation aims to further optimize.
What are the advantages of the industry’s first enhanced acoustic solar PVB interlayer?
The enhanced acoustic solar PVB interlayer jointly developed by Li Auto and Eastman innovatively introduces infrared-absorbing particles on the basis of the enhanced acoustic PVB formula, achieving solar control without sacrificing acoustic performance — a combination that is the first of its kind in the industry.
Superior solar control: Infrared blocking capability is improved by about 36%, making you feel more comfortable in summer.
Compared to conventional solutions, the new solution reduces the infrared transmittance (TIR) of the front door glass from 24.2% to 15.5%, improves solar performance by approximately 36%, and further optimizes the total solar transmittance.
What does this mean? Imagine sitting in your car after parking in the summer; the burning sensation of direct sunlight on your arms and face will be significantly reduced. Now, nearly 40% of infrared rays are directly blocked by the PVB interlayer before they reach the glass interior, ensuring a stable and comfortable experience inside the car even when driving in the sun.
Furthermore, better solar performance also helps reduce energy consumption, resulting in longer battery life. With the help of this new solution, the summer thermal management load can be reduced by 10 W, and the thermal management energy consumption under high-temperature conditions can be reduced by 5 W. This energy, which was originally used to combat high temperatures, can now be used in more valuable areas.
Superior acoustic performance: High-frequency sound insulation increased by 2 dB
In terms of acoustic performance, the new solution retains the core advantages of the enhanced acoustic PVB interlayer, namely, a 2 dB increase in high-frequency sound insulation, accurately covering the main frequency bands of wind noise in new energy vehicles and further enhancing the quiet experience inside the vehicle.
User value: Enjoy a cost-effective and worry-free heat-insulation experience when you purchase a car.
Among all vehicle glass components, the front door liftable windows have always lacked effective heat-insulation measures. Furthermore, due to their roll-forming process, silver plating cannot improve heat insulation. Therefore, using a PVB interlayer for heat insulation is a more reasonable technical approach for front door glass.
In terms of solar performance, the new solution has reached the level of mainstream high-performance interlayers. In other words, when purchasing a car, you can get a more complete heat-insulation configuration without having to invest extra effort and cost later.
Li Auto and Eastman jointly develop a new chapter in PVB material innovation.
The creation of this enhanced acoustic solar PVB interlayer is the result of in-depth collaboration between Li Auto and Eastman, a top global supplier. Through formula innovation and ingenious design, the two parties overcame long-standing technical challenges in the industry, demonstrating that enhanced acoustic and solar performance can coexist efficiently in the same interlayer material.
Currently, the material has passed the key performance verification required by Li Auto standards.
In the future, Li Auto will continue to deepen its innovation efforts in the field of PVB materials and tackle key problems in other new technology directions, promoting the innovation and implementation of more materials in stages, so as to create a quieter, more comfortable, and more energy-efficient travel experience for every user.