Fast charging and slow charging are the two main categories into which new energy vehicle charging techniques fall. Each of these two approaches is unique and appropriate for a variety of use cases.
I. Fast charging (DC fast charging)
Fast charging, that is, fast charging, also known as emergency charging. Through the DC charging pile of the charging station, this method primarily delivers DC high-voltage electricity directly to the power battery of new energy vehicles.
Operational concept
Through the DC charging pile, direct current is converted from the three-phase, four-wire AC voltage of 380 volts ± 57 volts used for fast charging. This type of direct current can quickly provide new energy vehicle charging services because it is relatively large, typically ranging from 150 to 400 amps. Usually, the charging takes 20 to 2 hours after parking because of the high current.
Advantages and limitations
The DC charging pile’s high input voltage allows it to produce a lot of power, which in turn allows for a wide output voltage and current adjustment range to satisfy the demands of rapid charging. However, it might also have an effect on the battery’s lifespan because of the high current.
Working equipment
The batteries of new energy vehicles are typically charged by “fast charging” in DC charging piles. Using a rectifier, it primarily converts AC to DC. A DC/DC converter then modifies the voltage and current to match the battery’s charging requirements.
II. Slow charging (AC slow charging)
This method primarily uses the household power plug and AC charging pile to connect to the AC charging port. The on-board charger then converts the 220-volt AC power to 330-volt DC to charge the power battery.
Operational concept
Slow charging uses low current, constant voltage or constant current charging; the charging period is typically 5 to 8 hours but can go up to 10 or 20 hours. In order to charge the batteries of new energy vehicles, 220 volts AC is converted to 330 volts DC using the on-board charger.
Advantages and limitations
Slow charging has less of an effect on battery life because of the low current. In addition, because household power supplies are primarily used for this purpose, installing and using them is not too difficult. But because of its lengthy charging time, it might not be appropriate in situations where quick charging is necessary.
Working equipment
The new energy vehicle’s AC charging pile is permanently mounted outside and connected to the grid of AC power. It is purely a power output device; it cannot be charged. For new energy vehicles, it must be connected to an on-board charger. To provide energy for the battery, the on-board charger transforms alternating current (AC) into direct current. The power supply in this process is managed in part by the AC charging pile.
III. Comparison of fast charging and slow charging
Currently, fast and slow charging are the two main ways that new energy vehicles are charged. While slow charging primarily uses household power supplies and AC charging piles for long-term small current charging, fast charging primarily provides large current through DC charging piles for charging in a short amount of time. Each of these two approaches has benefits and drawbacks that make them appropriate for various use cases. It will be easier for you to select and employ the appropriate charging methods if you are aware of the features and limitations associated with these two options.
