How to distinguish between DC charging stations and AC charging stations?

How to distinguish between DC charging stations and AC charging stations?

As we all know, charging stations are charging facilities for "refueling" electric vehicles. Charging stations are divided into AC charging stations and DC charging stations. So, what is the difference between AC and DC charging stations?

1、 What is a charging station?
Car charging station
Charging stations function similarly to gas dispensers in gas stations, and can be fixed on the ground or walls, installed in public buildings (such as public buildings, shopping malls, public parking lots, etc.) and residential parking lots or charging stations. They can charge various types of electric vehicles according to different voltage levels. The input end of the charging station is directly connected to the AC power grid, and the output end is equipped with a charging plug for charging electric vehicles.
Charging stations are currently divided into AC charging stations and DC charging stations. The AC pile outputs single-phase/three-phase AC power, which is converted into DC power by the on-board charger to charge the on-board battery. The power is generally small (7kw, 22kw, 40kw, etc.), and the charging speed is generally slow. Therefore, it is generally installed in residential parking lots and other places.
Communication Charging Diagram
Figure 1 Schematic diagram of AC charging
DC charging stations (also known as off board chargers) directly output DC electricity to charge the on-board battery, with high power (60kw, 120kw, 200kw or even higher) and fast charging speed, so they are generally installed at charging stations next to highways.
DC charging schematic diagram
Figure 2 Schematic diagram of DC charging

Generally speaking, DC charging piles have a rough shape (due to the presence of a certain number of AC-DC power modules inside, the higher the power, the more modules there are, and the larger the pile), while AC charging piles are relatively small. A more obvious difference is that the gun head (charging line) is different, with a 9-wire plug for DC charging stations and a 7-wire plug for AC charging stations.

2、 Charging line of DC charging station
DC charging schematic diagram
Figure 3 Schematic diagram of DC charging
As shown in the above figure, the output of the DC charging pile consists of 9 wires, namely:
DC power supply line: DC+, DC -;
Equipment ground wire: PE;
Charging communication line: S+, S -;
Charging connection confirmation lines: CC1, CC2;
Low voltage auxiliary power supply line: A+, A -.

The DC charging station charges electric vehicles through these 9 wires, and we will introduce the detailed charging process in subsequent articles.

3、 Charging lines for communication charging stations
Charging lines for communication charging stations
Figure 4 Schematic diagram of AC charging
As shown in the above figure, the output of the AC charging station consists of 7 wires, namely:
AC power lines: L1, L2, L3;
Equipment ground wire: PE;
Median line: N;
Connection confirmation line: CC;
Control guidance line: CP.
The communication charging station charges electric vehicles through these 7 wires.
The essential difference between AC charging stations and DC charging stations
The scientific name of a DC charging station is an off board charger, why is it called such a strange name?! DC charging stations are relative to AC charging stations.
An AC charging station is a specialized device that uses conduction to provide AC power to electric vehicles equipped with on-board chargers. AC charging stations include single-phase and three-phase AC charging stations.
Off board charger is a specialized device that is fixedly installed on the ground, converts AC power from the power grid into DC power, and uses conduction to charge the power battery of electric vehicles.
Principle diagram of communication charging station
Figure 5 Schematic diagram of AC charging station
Principle diagram of DC charging station
Figure 6 Schematic diagram of DC charging station
Figure 5 is a schematic diagram of the principle of an AC charging station, with AC input and output; Figure 6 is a schematic diagram of the principle of a DC charging station, with AC input and DC output. The charging station contains a charging machine, including rectification, filtering, DC/DC conversion, and corresponding control systems. Therefore, compared to DC charging stations, AC charging stations do not have charging machines inside, but only provide power. For AC charging stations, the charging unit is installed in electric vehicles. Due to the limited interior space of the car, the power of the on-board charging unit is generally not too high, so the charging time of the AC charging station is relatively long. However, DC charging stations are different. The charging station already includes a charging station inside. As we all know, compared to the interior space of the car, there is enough space on the ground to install a charging station, so its charging machine power can be made very large, and the charging time of the DC charging station is relatively short.
Therefore, the essential difference between AC charging stations and DC charging stations is whether they include a charger, which is why DC charging stations are called off board chargers. Similarly, an AC charging station can be referred to as a car charger.
Hot Keywords: AC Column Charging Post AC Charging Pile