The official website of Hengneng Technology shows that its silicon composite anode battery can travel about 300 kilometers after being charged for 5 minutes. Compared with the industry's fast charging standard (30 minutes), this reduces the charging wait time by 83.3%, improves the charging turnaround rate, and solves the dilemma of insufficient charging stations and long charging times. Silicon materials expand when used. What are the disadvantages? Is it a challenge to battery safety? And how should it be solved? At present, do other domestic manufacturers have similar silicon material battery systems with mass production progress?
Wang Liwei, Executive Director of Frost & Sullivan's Greater China region, was interviewed by China Business News and shared the potential of silicon materials in battery applications and the mass production progress of domestic manufacturers.
Q:Silicon materials expand when used. What are the disadvantages? Is it a challenge to battery safety? And how should it be solved?
Wang Liwei
Executive Director of Frost & Sullivan's Greater China region
The main disadvantages of the expansion problem of silicon materials are:
1. Volume expansion: When silicon is used as the anode of a battery, it experiences significant volume expansion (up to 300%) during charging, which may lead to structural damage of the battery material, affecting cycle stability and battery life; 2. Reduced conductivity: Expansion and contraction cause the conductivity of active materials to decrease, thus affecting the overall performance and charge-discharge efficiency of the battery; 3. Internal stress: Repeated expansion and contraction cause internal stress in the battery, which may lead to electrode peeling or cracking, increasing safety hazards. In extreme cases, due to the expansion of silicon materials, it may cause internal short circuits or thermal runaway in the battery, thus affecting battery safety. This phenomenon may lead to fires or explosions in extreme cases.
Regarding the above disadvantages, current solutions are:
1. Using composite materials composed of silicon and other materials (such as carbon) to balance energy density and expansion characteristics and reduce the impact of volume changes; 2. Developing flexible or solid electrolytes that can better adapt to the volume changes of electrodes, thereby improving battery safety and stability; 3. Optimizing the design and structure of batteries, such as using porous structures or nanostructures, to reduce stress concentration and improve cycle stability; 4. Adding coatings on the surface of silicon materials to reduce interfacial reactions and improve cycle stability.
Overall, the expansion problem of silicon materials has relatively little impact in battery use, especially after adopting advanced composite materials and optimized designs. These technologies can not only effectively alleviate the negative impacts brought by silicon volume changes but also maintain the high energy density and good cycle stability of batteries. Through reasonable material selection and structural design, battery manufacturers can improve product safety and performance, enabling silicon materials to exert their potential in battery applications.
Q:At present, do other domestic manufacturers have similar silicon material battery systems with mass production progress?
Wang Liwei
Executive Director of Frost & Sullivan's Greater China region
The silicon material battery systems of domestic enterprises mainly focus on mass production of anode materials such as silicon-carbon composite and silicon-oxygen composite. The shipments of domestic silicon material battery systems show a rapid growth trend and are gradually commercializing. The core enterprises mainly include BTR, Anhui Suntech Silicon Materials Co., Ltd., Putei Lai, etc., which are committed to technological research and development, production capacity expansion, manufacturing, etc. in the industrial chain.
For example, BTR is one of the earliest domestic enterprises to mass-produce silicon-based anode materials. Among them, silicon-carbon anode materials have been developed to the fifth generation product, with a specific capacity of over 2,000 mAh/g. As of the end of 2023, the production capacity of silicon-based anode materials reached 5,000 tons per year. Anhui Suntech Silicon Materials Co., Ltd. has mastered the core technology of mass synthesis of silicon-based anode precursors and successfully overcome the technical bottleneck in the embedding uniformity of pre-lithiated silicon materials. The shipments in 2021 were about 100 tons; and the company has laid out a 40,000-ton integrated silicon-based anode production capacity base in Ningbo. Among them, the first-phase production capacity construction will start trial production in mid-2024. Putei Lai launched the project construction of an annual output of 12,000 tons of silicon-based anode materials (monomers) in July 2023 and plans to start phased production gradually in 2025. Shenghua New Materials recently started the production of a 30,000-ton per year silicon-based anode material project at its Meishan base. At present, more than 40 manufacturers at home and abroad have laid out silicon material battery systems, and the industry has entered the commercial mass production stage.
*This interview has been published inChina Business NewsReporters are Zhu Chengxiang, and the original title is: "5 minutes of charging, 200 to 300 kilometers of range - Is there a solution to the problem of long queues for new energy vehicle charging at high speed?"
