DC fast charger can realize fast charging of electric vehicles


The development speed of new energy vehicles in the past two years is obvious to all. New energy vehicles have now become one of the leading industries in my country and the world. In 2017, my country's new energy production and sales reached 794,000 and 777,000 respectively, and the cumulative inventory reached 1.8 million, accounting for more than 50% of the global market, ranking first in the world for three consecutive years.

Ninety percent of new energy vehicles are electric vehicles that need to be charged. Therefore, charging facilities have become an important infrastructure for the development of new energy vehicles. At the same time, charging facilities have also become the biggest shortcoming restricting the rapid advancement of new energy vehicles. In the past two years, the relative hysteresis of infrastructure facilities such as fast chargers and charging piles has become increasingly prominent. Although the number of fast chargers and charging piles is increasing rapidly, it cannot be ignored that the growth scale of new energy vehicles is still significantly higher than that of fast chargers and charging piles. The gap is still widening.

According to the different charging power, charging piles can be divided into DC fast chargers and AC slow charging chargers: AC charging piles are fixedly installed in community parking lots, residential quarters, large shopping malls, service areas, roadside parking lots, etc. It is connected to the power grid to provide a controllable one-way AC power supply or a three-phase AC power supply device for the electric vehicle on-board charger. The AC charging pile itself does not have a charging function. It only provides power output and needs to be connected to an electric vehicle charger to charge the battery of an electric vehicle. Since the power of the on-board charger of an electric vehicle is generally relatively small, the AC charging pile cannot achieve fast charging.

DC fast chargers are also fixedly installed outdoors, such as community parking lots, residential quarters, large shopping malls, service areas, roadside parking lots, special electric vehicle charging stations, etc., connected to the grid to provide DC power for electric vehicle batteries Charging device. Since the DC fast charger can directly charge the battery of an electric vehicle, it generally uses a three-phase four-wire system or a three-phase three-wire system for power supply, and the output voltage and current can be adjusted in a wide range, so it can realize the fast charging of the electric vehicle. To put it simply, since lithium batteries must be charged by direct current, DC fast chargers can directly convert electrical energy from AC to DC, while AC charging piles need to be completed on the on-board charger of electric vehicles. The size and power of the charger are generally small, and the charging speed is slow. Due to the high construction cost, large construction area, and inflexibility of DC fast chargers, the current proportion of AC charging piles in the market is still relatively high.

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