The lithium battery industry is attracting hundreds of billions of yuan in investment. Where is the golden compass pointing? The 2018 China International Lithium Battery and Electric Vehicle Technology Development Summit Forum was held in Shanghai on April 20-21. This conference was jointly organized by: First Lithium Battery Network, First Electric Vehicle Network, China Charging Pile Network, Lithium Battery 100 Forum, and HeLi Exhibition. The China International Electric Vehicle and Charging/Swapping Technology Summit Forum was held concurrently. More than 40 guests gave speeches and shared their insights at the conference, and more than 500 guests attended.
Good morning everyone, I'm Guoneng Battery from Beijing. Today's topic is the development progress of high-performance batteries. I will be speaking in four parts: first, an introduction to the background; second, a discussion of the product technology roadmap; third, the design and related progress of high-performance batteries; and fourth, Guoneng Battery's R&D plan and overall production capacity.
First, let's discuss the overall background of new energy power. With the advancement of national policies and the increasing severity of environmental pollution, our demand for new energy vehicles is growing rapidly. Statistics show that sales increased from 740,000 vehicles in 2009 to 2.16 million vehicles in 2015, and are projected to reach 6.6 million vehicles globally by 2025. Sales of new energy vehicles are expected to increase significantly over the next decade. Looking at the vehicle types in the new energy market, passenger cars and special-purpose vehicles primarily use the ternary catalytic converter system. Currently, the ternary catalytic converter system is dominant. With national policies aiming for 300Wh/kg and a cost reduction to one yuan per watt-hour by 2020, [the market is now...]. Currently, the battery system development strategies of various companies are similar. The earliest approach was based on LFP + carbon and graphite with a capacity of 110-160Wh/KG. As the energy density of ternary cathode and anode systems increased, this energy level still did not meet the requirements. As the requirements became higher, the system continued to evolve. Later, NCM + carbon was used to achieve 160-220Wh/KG, and then filtered to lithium-rich + silicon at 260-350Wh/KG. This basically meets the national policy requirements for 2020. Finally, there are some cutting-edge technologies. The system we are currently working on is still based on ternary systems, and we are still researching ternary materials combined with graphite or silicon-carbon.
Our company's technology roadmap is as follows: last year, the system was 160Wh/KG, and this year the system is 180Wh/KG. Last year, the ternary system was mainly based on 523 and graphite, and this year we are gradually shifting to 622 graphite and silicon-carbon systems. In the future, we will further develop high-cracking silicon-carbon systems, and in the future, we will definitely move towards all-solid-state batteries. This is the battery development roadmap.
If we take the silicon-carbon system as the negative electrode technology route, we will first launch the 260Wh/KG 622 silicon-carbon system this year. The positive electrode is 622 and the negative electrode is silicon-carbon system. In 2019, we plan to launch 280Wh/KG to meet the requirement of 300Wh/KG in 2020.
I'll talk about silicon anodes, which have been the subject of much research. It's currently difficult for graphite to meet the national standard of 300-350Wh/kg, so there's been a lot of research on silicon anodes. We know that silicon has significant advantages, including high capacity, about 10 times that of conventional anodes. Also, the platform is graphite paste, offering better safety performance than graphite. However, it has some fatal drawbacks. During the lithium extraction and insertion process, there's a 300% volume change, compared to about 10% for graphite. This causes the active material to crack and pulverize, posing a significant challenge for our batteries: suppressing the volume expansion of silicon anodes. What problems does volume expansion cause? During charge-swap cycles, it leads to material pulverization and shedding, and also affects the formation of the SEI film and its impact on electrolytic consumption. Therefore, how do we solve the problems in the application of silicon anodes? We mainly consider two aspects. The first is the material itself; this is a challenge that requires collaboration between material manufacturers and battery manufacturers to overcome. Current improvements in materials, from the perspective of materials synthesis, mainly focus on the nano-sizing of silicon, primarily 0-dimensional, 1-dimensional, 2-dimensional, and 3-dimensional. 0-dimensional mainly involves creating nanoparticles, which must be made smaller; 1-dimensional involves creating nanowires; 2-dimensional involves nanofilms; and 3-dimensional involves porous structures.
The second is to perform encapsulation, which involves encapsulating silicon and carbon. The first step is to provide some buffer for expansion. This is mainly achieved by improving the conductivity of lithium batteries through metal doping. From the perspective of battery companies, how to make good use of this material and how to use it effectively in batteries are crucial. There are also related connectors. How to suppress the expansion of silicon during cycling? How do we understand the effects of electrolysis on the negative electrode during the binder process? How do we find a good additive or solvent to form a more stable SEI film during cycling, so that the SEI film is more stable and does not break so severely?
The nano-sizing of silicon mainly involves fabrication from the perspectives of 0-dimensional, 1-dimensional, and 2-dimensional dimensions, as mentioned above. Currently, the most commonly used method is the one shown in the lower right corner. Many companies use this approach, which first provides a buffer with bicyclic silicon to form a grape-like or pomegranate-like structure.
Then, in terms of battery development, the main focus is on binders and electrolytes. The most fundamental issue with binders is conductivity. How do binders improve the interface, and how do they increase the strength of the electrode interface? This section explains how to choose a good binder to improve the performance of the silicon system during battery operation. Therefore, our binder selection criteria include: first, better strength; second, better modulus and fatigue resistance; and better affinity for the electrolyte. Conductive agents peel off during cycling, requiring us to find better conductive agents to form a better network. Many people have mentioned carbon; currently, the best performing type is probably single-arm carbon nanotubes. Due to the conductive agent's role in connecting the binder, and the length and diameter of the tube, the conductivity is more complete, resulting in better overall conductivity. Using silicon anodes, we've created 622 and silicon-carbon system batteries with an energy density of approximately 264 Wh/kg and a cycle life of about 80% after 1000 cycles. However, while the basic performance is met, safety performance is somewhat lacking. A major problem with silicon-based batteries is that while an additive greatly helps with cycling, it encounters issues at high temperatures. This is a performance comparison of different electrolytes. Special additives can significantly improve various aspects of battery performance. We selected many binders, and the final electrolysis process yielded a substantial improvement.
The last two aspects focus on improving the material itself, suppressing expansion, and addressing issues from the perspective of battery applications. The first is how to achieve homogenization, and the second is how to make the material thinner according to density requirements. How to solve these problems, and how to determine the structure, density, and porosity? Then there are the research on binders and conductivity, electrolytes, and pre-reforming processes.
Now let me talk about our planning and production capacity. We have research institutes, system research institutes, BMS research centers, and materials research institutes. We also have a complete command center. Our entire system starts with materials and ends with battery recycling, creating a closed loop.
Regarding our production capacity, we currently have nine bases nationwide, with a capacity of approximately 1.2 GWh last year, ranking fifth in sales volume. Our customers are mainly located throughout the country, primarily concentrated in East China, North China, and coastal areas. These are our customer locations. Thank you.
