AC charging:
The electricity output by the State Grid is alternating current. As shown in the figure below, it has a sinusoidal switching pattern.
The battery of an electric vehicle can only accept DC power, so the AC power needs to be converted into DC power before it can be charged into the car battery. This requires a converter OBC (on-board charger). OBC is divided into one-way and two-way. One-way can only It can charge the vehicle, and can output 220V household AC power in both directions, which supports external discharge function;
Since OBC needs to be built-in, its size and heat dissipation are limited, and it is impossible to achieve high charging power.
DC charging:
The AC power is directly converted into DC power through the external OBC and input to the electric vehicle without using the OBC in the vehicle. The external OBC can have better heat dissipation conditions and is not limited by size, so it can provide higher voltage and current, better charging power and higher efficiency.