What is the trend of diode usage in new energy vehicle charging stations?

1, Technological iteration: Upgrading from traditional silicon-based to wide bandgap semiconductors
Traditional silicon-based diodes have long dominated the charging pile market due to their low cost and mature technology. However, with the development of new energy vehicles towards high voltage and high power, the performance bottleneck of silicon-based diodes is becoming increasingly prominent. For example, in the 800V high-voltage fast charging scenario, the high reverse recovery loss and low switching frequency of silicon-based diodes lead to a decrease in system efficiency, while stability issues in high-temperature environments also limit their application.

The rise of wide bandgap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) has provided a new direction for upgrading diode technology. Taking SiC Schottky diodes as an example, they have the following advantages:

Low on resistance: The critical breakdown field strength of SiC material is 10 times that of silicon, which can achieve a thinner drift layer, thereby reducing on resistance and energy loss.
High frequency switching characteristics: The reverse recovery time (t_rr) of SiC diodes is close to zero, significantly increasing the switching frequency and adapting to the requirements of high-frequency charging modules.
High temperature resistance: SiC devices can operate stably in environments above 200 ℃, reducing the complexity of heat dissipation design and improving system reliability.
According to market research institutions' predictions, the global SiC diode market size will exceed 3 billion US dollars by 2026, with a compound annual growth rate of 15%, of which the charging pile field will account for more than 30%. Domestic enterprises such as Silanwei and Yangjie Technology have achieved mass production of SiC Schottky diodes and gradually introduced high value-added scenarios such as charging piles and OBC (on-board chargers).

2, Material Innovation: Collaborative Optimization of Packaging Technology and Heat Dissipation Design
The improvement of diode performance not only relies on material innovation, but also requires collaborative optimization of packaging technology and heat dissipation design. In the application of charging stations, diodes need to withstand harsh conditions such as high current, high voltage, and high-frequency switching, and traditional packaging forms (such as DO-41, TO-220) are no longer able to meet the requirements. Currently, the industry is accelerating its evolution towards the following directions:

Compact packaging: DFN (double-sided flat no pins), SODFL (small patch diode) and other packaging forms have become the preferred choice for high-density PCB layouts due to their small size and low parasitic parameters. For example, DFN packaged diodes can reduce device size to 1/5 of traditional products while improving heat dissipation efficiency.
High heat dissipation packaging: For high-power charging modules, companies improve the thermal conductivity of diodes by using materials such as copper substrates and ceramic packaging. For example, a ceramic encapsulated SiC diode developed by a certain enterprise can reduce temperature rise by 40 ℃ and improve system efficiency by 2% compared to traditional silicon-based devices in a 350kW ultra fast charging scenario.
Integrated design: integrate multiple diode units into a single module, or package them together with MOSFET and drive circuit to form a power device complex (such as IPM module), which can simplify circuit design, reduce parasitic inductance, and improve system reliability.
3, Application scenario expansion: from charging module to full chain protection
With the upgrading of charging station technology, the application scenarios of diodes are extending from traditional charging modules to the entire chain, covering multiple aspects such as power management, electromagnetic compatibility (EMC), and safety protection

Power Management: In PFC (Power Factor Correction) circuits, fast recovery diodes combined with SiC MOSFETs can achieve high-efficiency and low harmonic energy conversion, meeting the requirements of IEC 61000-3-2 standard.
Electromagnetic compatibility: TVS (transient voltage suppression) diodes, with their nanosecond response speed, can effectively suppress surge voltages generated when charging stations are connected to vehicles, protecting the downstream circuit from damage. For example, a 5kW TVS diode developed by a certain enterprise has a clamping voltage accuracy of ± 5% and an increased surge absorption capacity of 10kA.
Safety protection: At the charging gun interface, the diode array can form anti reverse and overvoltage/overcurrent protection circuits to prevent equipment damage caused by misoperation. For example, a certain car model's charging system uses bidirectional TVS diodes to clamp the reverse voltage within a safe range, avoiding the risk of overcharging the battery pack.