Development trend of "three small electrics" of new energy vehicles

After the rapid development of the new energy vehicle market in 2020 and 2021, the growth rate of new energy penetration in global passenger cars has shown a clear slowdown since last year. The three major global automobile markets also show very different trends. According to the China Passenger Car Association, China's domestic retail new energy penetration rate has reached 40.3% in the first five months of this year. In comparison, in March 2024, the penetration rates of new energy vehicles in the United States and the European Union were 9.3% and 20.1%, respectively.

While the growth of the new energy market has slowed down, the overseas expansion of China's new energy vehicle industry chain has not slowed down, and the sales performance of plug-in hybrid vehicles has also been outstanding. According to the latest report from the China Passenger Car Association, from January to May 2024, the total sales volume of China's new energy vehicle market increased by 34.4% year-on-year, of which the sales volume of pure electric vehicles (BEV) increased by 17.4% year-on-year, and the sales volume of plug-in hybrid vehicles (PHEV) increased by a significant 70.1% year-on-year.

Looking ahead to the next few years, the new energy vehicle market will continue to grow steadily and will not easily change its dominant position in the automobile market. This also brings incremental demand for new energy "small three electrics".

Due to the different power systems, the "three electrics" of new energy vehicles have replaced the fuel tank, engine, gearbox, etc. of traditional fuel vehicles. The incremental components of new energy vehicles mainly include the big three electrics (power battery, motor controller, motor) and the small three electrics (on-board charger OBC, DC/DC converter, high-voltage distribution box PDU).

Based on the commonalities among the three small electric vehicles, integrated solutions and even all-in-one electrified product designs have become mainstream. Most current products integrate the originally dispersed controllers into one housing in a physical way to form a new "integrated" product. This integration method reduces the total weight and volume of the product, which is conducive to the lightweight design of the vehicle. At the same time, the integration of multiple products optimizes the total cost of parts.

Su Zirui, marketing manager of electrification system at STMicroelectronics' New Energy Vehicle Technology Innovation Center, pointed out that multi-directional electrification integration in the power domain is a major development trend in the market. As new energy vehicle platforms move toward 800V high voltage, the OBC power segment has expanded from 6.6kW to 11kW or even higher, and the trend of selective electrification integration of power domain components has intensified, such as the combination of OBC and DC/DC+PDU, as well as battery management BMS (BMU part) + VCU, or Inverter+DC/DC, etc. Taking STMicroelectronics as an example, it has realized an all-in-one power domain controller electrification integration solution prototype, which includes five-in-one: BMU, VCU, Inverter, OBC+DC/DC. "The purpose of this is to provide customers with flexible integration solutions and choose the integration form according to their own needs and market strategies."

For the application of OBC+DC/DC integrated on-board charger, facing different voltage platforms, there will be various development directions and possibilities. First of all, in terms of topology and power device selection, the current traditional mature solution is mainly based on PFC+CLLC for the OBC part, and some unipolar topology OBC solutions have also been seen. In terms of power device selection, the use of third-generation semiconductor silicon carbide devices has a certain effect on improving the energy efficiency of new energy vehicles. The improvement of energy efficiency means a longer driving range, which is also a consideration for sustainable development.

Su Zirui pointed out that as the market develops, all-in-one applications will put forward newer and more detailed requirements for MCUs. "The feedback we have received from the MCU market mainly focuses on these resources: first, the number of MCU main cores and lockable steps and the main frequency of the core; second, the demand for MCU storage resources. For example, OTA requires MCU storage resources to have a larger capacity to support the storage and operation of more code; whether the MCU has rich hardware resources, sufficient high-speed ADC/DAC resources, counter modules with different functions, digital/analog comparator modules, hardware encryption modules and other different resources to support customers' diverse needs, which is more conducive to customers' development of MCU platform."

Of course, the evolution of such an integrated form requires time to accumulate technology and further system verification. When choosing OBC-related solutions, customers also pay more attention to product maturity, system coordination, and certain innovation while having sufficient stability. Su Zirui said, "The current OBC+DC/DC market is becoming mature. When we introduce new solutions, we will undoubtedly consider the improvement brought by traditional solutions and the continuation of reliability. After all, after time and market verification, traditional solutions have been recognized by customers. At the same time, in the current fiercely competitive Chinese automobile market, we must also put ourselves in the shoes of the industry environment pressure faced by the OEMs. As an OBC+DC/DC solution, how can we use innovative ideas and technical means to bring better charging efficiency, reduce mileage anxiety, and take into account cost requirements at the same time."

In general, the development trend of electrification is mainly evolving towards platformization, integration, and cross-domain integration, from the initial discrete "big three electrics, small three electrics" components to integrated power domain modules, which can reduce and optimize BOM costs, the number of overall chips, and the development cycle, as well as follow the trend of "software-defined cars" for a more efficient OTA experience, improve customer development efficiency, and fit the current trend of rapid development and iteration of China's new energy vehicle market. When it comes to the cooperation model in the development of electrification, ST also provides a variety of support services, such as cooperative development with OEMs and Tier 1 in the industry, in-depth exchanges, and cooperation with localized technical application teams to help customer projects quickly land on the market and jointly promote the development of electrification.