Investment advice
At present, the mainstream of electric vehicle voltage platform is 400-500v, which has the problems of mileage anxiety and slow charging speed. Electric vehicle 800V high voltage system + super fast charging can realize charging for 10 minutes and endurance of more than 300km, which can effectively solve the anxiety of charging and endurance, and is expected to become the main trend. The characteristics of SiC material make the MOSFET structure easily cover 650v-3300v, and the conduction loss is small; At the same time, 90% of the driving conditions are within 30% of the rated power of the main drive motor, which is in the high-efficiency area of silicon carbide; In addition, the power frequency and motor speed of SiC main drive increase, the torque decreases and the volume decreases at the same power; The 800V platform model of SiC MOSFET for main drive controller can save energy by 5% – 10%. Sicmosfet is a better choice for power semiconductors in 800V high voltage system. Most of the 800V high voltage system schemes that have been released or will be released at present choose SiC MOSFET. For super fast charging, the best way is to use the 800V platform. When using the 800V super fast charging, the power of the charging pile power module is required to be expanded to 40kW / 60kW, and the efficiency of the full SiC scheme can be improved by 2%. 800V high voltage system will drive the main drive inverter, on-board OBC, DC-DC, PDU, overcharge and fast charging pile to start large-scale application of silicon carbide, and silicon carbide will usher in a sweet moment. Yole predicts that the market scale of silicon carbide power devices is expected to reach US $5 billion in 2026, of which more than 60% will be used in the field of new energy vehicles.
Industry perspective
800V high voltage system, silicon carbide benefits deeply. The power device is the core energy conversion unit of the electric vehicle inverter. If the DC bus voltage is increased to more than 800V, the withstand voltage of the corresponding power device needs to be increased to about 1200V. SiC has high withstand voltage characteristics. Under the withstand voltage of 1200V, the impedance is much lower than Si, and the corresponding conduction loss will be reduced accordingly. At the same time, since SiC can select MOSFET package under the withstand voltage of 1200V, the switching loss can be greatly reduced. Wolfspeed, the global silicon carbide leader, controls the conduction resistance of 1200V silicon carbide at about 3M Ω cm2. According to st data, the loss of silicon carbide device is much lower than that of Si based IGBT. Under the commonly used 25% load, the loss of silicon carbide device is lower than 80% of IGBT, and the advantage is more obvious at 1200V. According to the research data of Infineon, Ford, Mercedes Benz, Hyundai and other companies, SiC applied to 800V system can save energy by 5-10%.
On board OBC, DC-DC, PDU, charging pile and high-speed rail transit began to apply silicon carbide on a large scale. When the on-board OBC is transferred from Si device to SiC device design, the number of power devices and grid drives is reduced by more than 30%, and the switching frequency is more than doubled. It reduces the component size, weight and cost of the power conversion system, and improves the operation efficiency. The system efficiency can be increased by 1.5% ~ 2.0%. For the 800V system model, it is necessary to install a high-power boost module on the vehicle, and then charge the power battery on the ordinary charging pile. Silicon carbide has the advantages of high voltage resistance, high temperature resistance and low switching loss. Silicon carbide has been widely used. With the increasing demand for overcharge and fast charge, all silicon carbide modules are widely used in charging piles. According to the industrial chain research, most of the high-performance charging piles with 800V architecture use all silicon carbide modules. China’s public charging piles have developed rapidly, and the new increment from January to August 2021 increased by 322% year-on-year. According to the research data of Siemens, when silicon carbide is applied to rail transit, the motor noise is generally reduced, and the energy consumption is reduced by about 10%. Silicon carbide is expected to be popularized and used in rail transit in Europe. Shinkansen in Japan has begun to use silicon carbide in large quantities, and silicon carbide has been used in 8 subways in China. Yole predicts that the market scale of silicon carbide power devices is expected to reach US $5 billion in 2026, of which more than 60% will be used in the field of new energy vehicles.
Recommended combinations: Sanan Optoelectronics Co.Ltd(600703) , Starpower Semiconductor Ltd(603290) , Zhuzhou Crrc Times Electric Co.Ltd(688187) , Wingtech Technology Co.Ltd(600745) , Tianyue advanced.
Risk statement
The permeability of 800V system did not meet expectations, SiC cost remained high, and the development of charging pile was lower than expected.
（ Sinolink Securities Co.Ltd(600109) ）
