The semiconductor “heart” of the charging pile

With the continuous breakthroughs in the penetration rate of new energy vehicles, from only 1% in 2016, to now, the penetration rate of electric vehicles in Shanghai has exceeded 50%. This is inseparable from the continuous development of the upstream and downstream of the industrial chain, as well as the continuous improvement of semiconductor components . . The number and distribution density of charging piles determine users’ intuitive feelings about whether they are anxious about the cruising range of new energy vehicles, as well as their advance consideration of whether subsequent recharge is convenient.

In addition to private AC charging piles that can slowly charge at night, public charging piles are more critical, especially public DC charging piles (fast charging) that are becoming the main force. And what exactly is the semiconductor “heart” that DC charging piles have? In addition to well-known international manufacturers, what other local companies are actively deploying? Today, Yifei.com will conduct an in-depth analysis on this.

DC fast charging usually refers to the internal AC-DC conversion module of the charging pile itself, which converts the AC power in the power grid or energy storage equipment into DC power and directly charges the car without borrowing OBC. The DC fast charging power depends on the output power of the charging pile itself and the BMS ( battery management system ). If the battery voltage is upgraded to 800V, the DC fast charging power will usually exceed 120 kW, and the high power characteristics of silicon carbide devices can be used. , thereby improving charging efficiency and shortening charging time.

The semiconductor “heart” of the charging pile

In recent years, benefiting from the rapid growth of new energy vehicles, the supporting charging pile market has also shown rapid development. According to Yidu Data, China's charging facilities market will reach 287.02 billion yuan by 2026, with a compound growth rate of 37.83% from 2022 to 2026.

Figure, China’s new energy vehicle ownership, number of charging piles and vehicle-to-pile ratio from 2015 to 2022 Data source: China Charging Alliance, China Automobile Association, etc.

According to statistics from the China Charging Alliance, there will be 62,000 more public charging piles in July 2023 than in June, a year-on-year increase of 40.4% in July. As of July 2023, the cumulative number of charging infrastructure nationwide is 6.928 million units, a year-on-year increase of 74.1%. Charging infrastructure is growing rapidly in parallel with new energy vehicles.

As the "heart" of DC charging equipment, the charging module is mainly composed of semiconductor components such as chips , power devices , capacitors , magnetic components, and PCBs . Power devices are the most commonly used semiconductors in this "heart".

Power devices are one of the core devices in the electronics industry chain. It can realize power conversion and circuit control. It mainly plays the functions of power conversion, power amplification, power switch, line protection, inverter (DC to AC) and rectification (AC to DC) in the circuit.

The power devices in the charging module mainly include  MOSFET  and  IGBT  , each of which is suitable for different voltage ranges and both are used in charging modules. Compared with Si-based devices, SiC  MOS has excellent characteristics such as lower conduction loss, lower switching loss , and higher switching frequency, and can work efficiently in harsh environments such as high temperature, high pressure, and interference, and can significantly Improve the power density of the charging module, extend the service life of the charging module, and reduce the operation and maintenance costs of operators and pile companies.

Figure, Impact of SiC on charging time of electric vehicles Source: Infineon

Obviously, the addition of SiC will greatly increase the power density and extend the service life of the charging module. As a third-generation power semiconductor , the application of silicon carbide will also greatly accelerate the performance of DC charging piles.

In 2020, charging piles were included in one of the country’s seven “new infrastructure” areas. During the two sessions in 2020, the "Government Work Report" also emphasized "building charging piles, promoting new energy vehicles, stimulating new consumer demand, and assisting industrial upgrading."

Under the operating power and current requirements required by public DC charging piles, the power devices used are mainly high-voltage MOSFETs. Super junction MOSFET has become a mainstream power device application product for charging piles due to its lower conduction loss and switching loss, high reliability, and high power density. It is specifically used in power factor correction ("PFC") of charging piles. , DC- DC converters and auxiliary power modules , etc. Super junction MOSFET will fully benefit from the rapid construction of charging piles. According to Infineon statistics, a 100kW charging pile requires power devices worth US$200-300. It is expected that with the continuous construction of charging piles, power devices, especially super-junction MOSFETs, will usher in rapid development opportunities.

Domestic power semiconductor manufacturers rushing to deploy charging piles

Dongwei Semiconductor: Focusing on the field of charging piles, new products such as silicon carbon devices and TGBT are frequently released

As the first company in China to begin replacing imported devices for use in DC charging piles, Dongwei Semiconductor has obtained patents for high-voltage super-junction technology with innovative structures through years of independent research and development, breaking through the monopoly of major international manufacturers on the use of MOSFETs by charging pile companies.

On April 13, 2016, the company took the lead in mass-producing China's first independently developed power semiconductor core device for charging piles, and entered the industrial power application field that has long been monopolized by international manufacturers.

Gong Yi, chairman and general manager of Dongwei Semiconductor, once said that after localization, the overall cost of charging piles will be reduced, which will have a strong promotion effect on the popularity of new energy vehicles.

In 2022, Dongwei Semiconductor's operating income will be 1.116 billion yuan, a year-on-year increase of 42.74%. Among them, the revenue from the field of new energy vehicle DC charging piles accounted for approximately 15% of the current main business revenue, an increase of approximately 6% from the same period last year, and the revenue from the vehicle charger field accounted for more than 21% of the current main business revenue, an increase from the previous year. An increase of approximately 500% over the same period last year. The two charging application fields have seen different growth rates.

In terms of specific products, Dongwei Semiconductor's new Tri-gate IGBT (TGBT) new power device with an original device structure has achieved rapid growth, and has been applied in high-efficiency power conversion systems including DC charging piles with its excellent product performance. It has been used in many Achieve batch supply for key customers.

In terms of third-generation semiconductor R&D and industrialization, Dongwei Semiconductor has also made advance arrangements. Great progress has been made in research and development of SiC diodes , SiC MOSFETs and Si²C MOSFET devices. Among them, Si²C MOSFET has been shipped in small quantities and entered the mass production stage.

Si²C MOSFET is a device with an original structure developed by Dongwei Semiconductor based on its power semiconductor design and process capabilities accumulated over many years. Different designs lead to differences in craftsmanship.

Si²C MOSFET devices overcome the shortcomings of high cost and Vth drift of traditional SiC MOSFETs. They have excellent gate oxide reliability and high gate-source withstand voltage. They also have extremely low reverse recovery time and reverse recovery charge. They are easy to apply and suitable for use. Based on totem pole bridgeless PFC, H-bridge inverter and other topologies , it can be used in various application scenarios such as new energy vehicle on-board chargers, energy storage inverters , high-efficiency communication power supplies , high-efficiency server power supplies, etc. SiC MOSFET replacement, high cost performance will bring broad market prospects.

Dongwei Semiconductor mentioned in the announcement that new energy vehicles and DC charging piles are the company’s key expansion directions. Its high-voltage super-junction MOSFETs and medium-low voltage SGT MOSFETs have been shipped in batches to BYD , Kesku, Harman, United Electronics and other companies.

With the rapid increase in the penetration rate of the new energy vehicle market, the charging pile module market will also usher in a new round of rapid growth. The cooperative relationship established by Dongwei Semiconductor with major domestic DC charging pile power module manufacturers means that it continues to ship in batches and brings considerable performance growth.

Table, related products of Dongwei Semiconductor that have been used in charging piles and their technical characteristics. Source: compiled by Yifei.com

In general, in addition to the conventional high-voltage super-junction MOSFETs and medium and low-voltage SGT MOSFETs, Dongwei Semiconductor's silicon cubic carbon devices and TGBT will also play an important role in the field of charging pile power semiconductors.

China Resources Micro: Focusing on SiC MOSFETs

In December 2021, the main application areas of the 1200V SiC MOSFET products launched by China Resources Micro include new energy vehicle charging piles. At the beginning of 2022, we will quickly launch targeted series of products such as 160 milliohms, 100 milliohms, 80 milliohms, and 40 milliohms.