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Introduction: As China's new energy vehicle market continues to expand, the charging pile market has broad growth prospects. SiC power devices can switch at higher frequencies than Si-based power devices and deliver high power density in an ultra-compact footprint, so their penetration in charging pile power modules keeps rising.
Broad Prospects for the Charging Pile Market
China's charging market was initially dominated by commercial vehicles, with centralized charging stations taking the lead; as passenger vehicle sales have surged, distributed charging piles have grown rapidly. The national plan for 2015–2020 called for 12,000 new charging stations and 4.8 million new charging piles, targeting a vehicle-to-pile ratio of about 1:1 by 2020. According to the Guidelines on the Development of Electric Vehicle Charging Infrastructure (2015–2020), China's EV fleet will exceed 5 million by 2020, and based on the charging infrastructure requirements of EVs across application segments, the national target for 2020 is a vehicle-to-pile ratio of essentially 1:1. China now has the world's largest public charging pile fleet, and growing passenger vehicle sales are driving up the share of private charging piles, but overall build-out still lags the plan. As of the end of September 2018, China had 2.21 million new energy vehicles and 686,000 charging piles, a vehicle-to-pile ratio of about 3.31:1 — still well behind the target.
Fierce Competition in Charging Pile Equipment Manufacturing
The charging pile equipment manufacturing market is fragmented, with players of widely varying scale; most mainstream brands are power equipment manufacturers that have expanded their product lines. China's charging pile equipment makers include brand owners and OEMs. Brand owners are numerous, and the mainstream manufacturers come mainly from the power supply equipment, power supply, and electronics industries — companies that generally have strong talent and technology foundations and well-developed R&D, manufacturing, and service systems. Companies such as TGOOD, Wanbang Charging, Clou Electronics, Wanma New Energy, and BYD also run charging pile equipment manufacturing businesses, with operations spanning equipment production, construction, and operation.
Charging Module Prices Fall Sharply
The charging module is a key charging pile component, accounting for 50% of total equipment cost — the core part. A charging pile module converts AC power from the grid into DC power for charging. In operation, three-phase AC is rectified and filtered into a DC input voltage that feeds an IGBT bridge. A controller drives the IGBTs through a gate driver circuit, converting the DC voltage back to AC. That AC voltage is then stepped and isolated by a high-frequency transformer, rectified and filtered again into DC pulses, and used to charge the battery pack. The charging module not only delivers power but also controls and converts the circuit to keep the supply stable.
China's charging module market has many participants, with the large players mostly tracing back to the Emerson-Huawei Electric team, including Tonghe Technology and Increase. There are numerous domestic charging power supply system and complete equipment manufacturers; those that produce their own EV charging power modules include Tonghe Technology, Increase, Infypower, Lingkang, Huawei, and ZTE.
Tonghe Technology's power module customers include well-known power equipment makers such as Luneng Intelligence, NARI, and Guowang Puruite, as well as major vehicle manufacturers such as Yutong Bus and Foton Motor. Increase's main customers include Huashang Sanyou, Hexin Ruitong, and Zhuhai Taitan Technology. Zhongheng Electric also holds core high-power conversion module technology, mostly serving its own charging pile equipment manufacturing.
Charging pile module power ratings are rising fast while prices fall sharply, gradually marginalizing small and mid-sized module makers. As traction battery and vehicle technology advance, new energy vehicle driving range is clearly trending upward, and charging pile module power is rising accordingly. Technical competition among charging module makers is intensifying, and module prices have fallen sharply in recent years, from RMB 0.4/W to RMB 0.2/W. Many small and mid-sized module makers are being marginalized, taking a wait-and-see stance or even preparing to exit the market.
Accelerating Adoption of SiC Power Devices in Charging Pile Equipment
Taking DC charging piles as an example, CASA estimates thatSiC power devices in EV charging piles have reached an average penetration rate of 10%, and the 2018 market for SiC power electronic devices in DC charging piles was about RMB 130 million, more than double the 2017 figure.
Because SiC transistors can switch at higher frequencies than silicon-based power devices, they deliver high power density in an ultra-compact footprint — small size while still supporting fast charging. Fast-charging several vehicles at once requires hundreds of kW, and an EV charging station needs over a megawatt, comparable to the power demand of a residential community. Traditional silicon-based power devices are bulky, whereas SiC modules meet the power requirements in a much smaller footprint.
But using SiC devices brings its own design challenges:
1. Parasitic effects: SiC devices have low intrinsic parasitics, so parasitics from PCB and component layout have an outsized effect;
2. SiC gate drive design: at high-frequency operation, the gate driver circuit's power dissipation, speed, and protection design become more complex;
3. High-frequency EMI: high-frequency operation of SiC devices causes severe EMI, requiring a balance between switching speed and EMI performance;
4. Reliability: long-term reliability of the SiC MOSFET gate oxide layer.
