With soaring oil prices and global policy support, electric vehicles will become increasingly popular. Slowly electric vehicles will become the mainstream of the market. Next, let’s learn about the working principle and charging principle of electric vehicles.

New energy pure electric vehicle charging method

At present, the charging methods of electric vehicles include slow charging, fast charging, battery replacement, wireless charging and mobile charging, but most electric vehicles on the market only support slow charging and fast charging, and are equipped with slow charging and fast charging interfaces. Other charging methods are not widely used yet.

1.Slow charging (conventional charging, car charging) is suitable for car chargers and home wall-mounted charging piles. The current and power are relatively small, and the general charging time takes 6-8 hours.

2.Fast charging (ground charging, emergency charging) includes two forms of charging stations and mobile charging vehicles. It mainly charges the battery directly with a large current through an off-board charger, so that the battery can be charged to about 80% in a short time. , Generally, it can be fully charged in 1 hour.

3.For battery replacement, the car battery is charged by replacing the power battery. When the power battery is exhausted, replace the low-power battery pack with a fully charged battery, and send the replaced battery to the replacement station for slow charging.

4.Wireless charging is to automatically connect to the grid for charging and discharging through the wireless charging source board embedded in the road and parking space without using wires and cables. This charging method is convenient and safe to use, but it has not been used in mass production for the time being.

5.Mobile charging (MAC) is an extension of wireless charging. Car owners do not need to look for charging stations and spend time charging. They can charge while cruising on the road. The mobile charging system will be buried under a section of road surface to mark out the charging section without requiring additional space.

Lithium-ion batteries are far more complex and sophisticated than simple gas tanks. Charge them too quickly and they can get too hot and even get damaged. Overcharge them and they will break. Let them sit without charging or discharging and they will lose capacity. To extend battery life, EV manufacturers have developed charging programs, or “curves,” to optimally manage the charging process and maintain capacity over time. Let’s now understand why lithium-based batteries require charging profiles, and how EV manufacturers and charger manufacturers can work together to provide them.Electric Vehicle Charging Principle

How does a lithium-ion battery work?

In short, lithium-ion batteries store and release energy through chemical reactions. During this reaction, lithium ions move through the electrolyte from one electrode to the other, losing or gaining electrons along the way. Pass current through the battery and “charge it”. Connect the terminals to the circuit and discharge.

What is an EV charging profile?

Charging and discharging Li-ion batteries generates heat, and too much heat can shorten the long-term life of the battery. Fast-charging lithium-ion batteries are a delicate balance between speed and heat. Charge them too quickly and they will overheat. To keep the battery cool while charging quickly, automakers vary the charge over time. Typically, fast charging has two phases, a constant current phase and a constant voltage or “top charge” phase. During the constant current phase, the battery charges as fast as possible without overheating. You may have noticed that many electric car manufacturers say their cars can be quickly charged between 20% and 80% in a short period of time. That is the constant current phase, which is the fastest during the charge cycle. After the constant current phase, the charger enters the constant voltage phase, which is slower. Charging an EV battery from 80% to 90% can take just as long as charging it from 40% to 80%. When a battery is close to being fully charged, it’s crucial to make sure it doesn’t overheat, and therefore charge more slowly.

Electric vehicle charging principle

The power battery of the electric vehicle can only receive direct current (DC) voltage, while the power grid/household outlets provide alternating current, which can’t directly charge the battery of the vehicle. It needs AC-DC conversion, and the converted DC can charge the battery. All alternating current (AC) charging piles are only the power supply lines of charging equipment (OBC), although they may be very intelligent power supply lines; The power module is integrated in the direct current (DC) pile, AC-DC conversion is carried out in the pile, and the direct current is output to charge the battery.

The alternating current (AC) pile supplies power for OnBoard Charger: OBC), and the on-board charger carries out AC-DC rectification conversion to charge the power battery; While the direct current (DC) pile directly charges the battery.