Investment advice
To solve the anxiety of charging and endurance, 800V system came into being. The development of new energy vehicles is in full swing, with obvious advantages in power performance, intelligence and cost saving, but electric vehicles still face the problem of mileage anxiety. In order to extend the mileage, major manufacturers have installed batteries one after another, and the battery addition strategy after exceeding a certain amount of electricity reduces the marginal revenue of endurance. With the increase of battery capacity, the endurance anxiety has been reduced a lot, and the charging anxiety began to surface. Fast charging can effectively solve the charging and endurance anxiety, and the 800V high-voltage platform scheme of new energy vehicles came into being. Xiaopeng released that the g9800v platform adopts SiC devices, which can realize charging for 5 minutes and endurance of 200 km; Lan Tu 800V system can realize charging for 10 minutes and endurance of 400 km; At present, more than 20 automobile brands have launched or determined to launch 800V system in the world. Based on the obvious core advantages of 800V system, we study and judge that it is expected to penetrate rapidly in the field of electric vehicles and are optimistic about the beneficial industrial chain.
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. 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. 90% of the driving conditions are within 30% of the rated power of the main drive motor and in the high-efficiency area of silicon carbide; The power frequency and motor speed of SiC main drive increase, the torque decreases and the volume decreases at the same power. 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%. In addition, on-board OBC, DC-DC and PDU began to apply silicon carbide on a large scale. On board OBC adopts silicon carbide devices, and the system efficiency can be improved by 1.5% - 2.0%; The supporting high-voltage fast charging and super charging piles also increase the amount of silicon carbide. 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.
The volume and price of isolation chips have risen. 800V electric drive system has higher transient common mode interference. For the isolated drive chip of inverter, it needs to be able to withstand common mode transient interference of more than 100kV / us. With the increase of 800V voltage, the system needs higher insulation and withstand voltage requirements of primary and secondary sides. It is mainly reflected in two aspects: one is insulation working voltage. For the system with 800V voltage, the isolation chip across the isolation band needs to bear at least 800V insulation working voltage to ensure the working life of at least 15-20 years. Overall, the usage and value of 800V system isolation chips have increased significantly.
The value of thin film capacitor and high voltage DC relay has increased. With the application of SiC devices in 800V system, noise countermeasures become more and more important, and sometimes large surge voltage will occur. On the whole, the service temperature and voltage of 800V system for thin film capacitors will be improved, the requirements for reliability and stability will be further improved, and the predicted value will be improved to a certain extent. The requirements of 800V system for high-voltage relay are further improved. The original resin packaging needs to be replaced with ceramic packaging. The voltage and current of 800V platform are higher and the arc is more serious. The performance requirements for withstand voltage grade, current carrying capacity, arc extinguishing and service life are improved. The products need to be improved in many aspects such as contact material and arc extinguishing technology, and the value is also improved to a certain extent.
Recommended combinations: Sanan Optoelectronics Co.Ltd(600703) , Xiamen Faratronic Co.Ltd(600563) , nano core micro, Starpower Semiconductor Ltd(603290) body, Zhuzhou Crrc Times Electric Co.Ltd(688187) .
Risk statement
The penetration rate of 800V system did not meet expectations, SiC cost remained high, and the development of new energy vehicles was lower than expected.
（ Sinolink Securities Co.Ltd(600109) ）
