Charging Pile

There are many types of infrastructure for electric vehicles, including various private and public charging piles, as well as some general charging piles suitable for passenger cars and buses.

Standard charging piles are classified according to 3 indicators: output power level, physical interface, and communication protocol. The communication methods of different charging protocols are different. The protocol relies on different physical connections, and there is almost no compatibility between different physical connections. Table 5 shows the charging pile standards and supporting protocols implemented in different regions. In the case of using secondary and tertiary AC charging piles, each type has a corresponding agreement, and Tesla also uses the same agreement. But in the case of using DC fast charging piles, the combined charging system (CCS) connector is suitable for the power line communication (PLC) protocol (usually used for smart grid communication), while CHAdeMO, Tesla and GB/T use the controller area network Communication (originally developed for in-car components) protocol. 

According to the "Global Electric Vehicle Outlook" recently published by the International Energy Agency (IEA), the number of public charging piles for electric vehicles jumped 60% in 2019, the largest increase in the past three years, and exceeded the sales growth of electric vehicles themselves. Specifically, the number of slow-charging and fast-charging charging piles worldwide has reached 862,000, of which China holds 60%.

The current charging strategy and communication protocol are mainly for passenger cars and light commercial vehicles, but they can also be applied to other fields.

①Most electric two-wheeled vehicles use the first-level low-power charging strategy. Of course, electric tricycles with higher power can also use the second-level mid-power charging pile.

②The charging scheme of electric buses has developed into two categories: slow charging at the station at night when the electricity price is low (multiple charging interfaces and charging protocols can be used); high-power charging at the station at any time.

③Electric buses are equipped with huge battery packs, so slow charging piles at stations also need more than 22kW of power to meet the demand for full battery packs at night; in most cases, the power of DC fast charging piles is generally greater than 50kW. The newly launched buses already support a 150kW contact charging method.

④In view of the fact that the number of electric buses on the road in China is much larger than that in other countries, and China prefers the charging method of slow charging at stations, many medium and large electric vehicles on the road currently use the fast charging mode of the GB/T DC charging standard.

⑤ CHAdeMO and CCS also support passenger cars and trucks charged by pantograph. Another supporting pantograph charging method is OppCharge, which can reach a charging power of 150-450kW and is compatible with IEC61851-23 (DC) and ISO15118 standards.

⑥ Existing standards need to be further improved to adapt to more and more electrified vehicles, especially for high-power applications such as electric trucks, which also have long-distance and heavy-load requirements. Typical examples are the Semi electric vehicles released by Tesla. truck.

In the "Electric Vehicle Charging Infrastructure Development Guide (2015-2020)" issued by the National Development and Reform Commission and other ministries and commissions in 2015, the goal of achieving a 1:1 ratio of vehicles to piles was set very early in 2020. However, the actual vehicle to pile ratio is currently around 3:1, and the number of charging piles is still insufficient.

To this end, in March 2020, the construction of charging piles was included in the seven key areas of "new infrastructure". State Grid announced that it will invest 2.7 billion yuan to build 78,000 charging piles, a year-on-year increase of 10 times; China Southern Power Grid plans to invest 21.5 billion yuan in four years to build 380,000 charging piles, more than 10 times the existing number. In addition, Telaidian, CATL and other companies are also deploying charging pile operations.