The charging process of AC pile mainly depends on the vehicle charger, the volume and power of the vehicle charger is limited, so in most cases, it can only be slow charging.
Combined with the use of private passenger cars, this mode is in line with the needs of its low-frequency mode, and it is also good for the battery.
Dc pile, directly charging the battery under the on-board BMS management, can meet the charging needs of commercial vehicles (buses, buses, taxis, etc.), high-frequency vehicles (online car, business vehicles, etc.), and emergency vehicles (although more or less sacrifice the service life of the battery).
Because it is non-vehicle, it is no longer sensitive to volume, and of course, more high-power conversion components can be used. This is also an economic consideration. A set of high-power charging devices that can serve multiple vehicles.
Strictly speaking, the fast charging pile also has AC (depending on the power of the on-board charger).
For example: the charging scheme used by BYD buses. This solution is good for the deployment of charging piles, as long as the 380V power supply is solved, the rest is the conventional low-voltage distribution scheme, and the difficulty of the construction of charging stations is minimized. However, the disadvantage is that each car must be configured with an on-board charger of the same power. In this case, the overall economy of the scheme is obviously inferior to that of the DC fast charge scheme. In this regard, the solution envisaged by BYD (personal understanding) is that the charge conversion circuit is achieved by using the different working modes of its V2G vehicle drivers, so it is not an additional set of charging circuits, so it will not add too much additional cost to the vehicle.