What Is a Charging Station?

Electric vehicle charging stations and mobile phone charging stations are similar to car gas stations. They are a device that "powers up" batteries and mobile phones. It is a high-efficiency charger that can quickly charge electric vehicles, mobile phones, electric tricycles, and old-time scooters. "Electric vehicle fast charging stations" and hand charging stations can be set up at street shops, street communities, next to newsstands, car storage sheds, betting points, etc., like car gas stations. The electric vehicle charging station uses pulses, which has a good desulfurization effect. It can first activate the battery and then perform maintenance-type fast charging. It has timing, full alarm, computer fast charge, password control, self-recognition voltage, multiple protection, four-way Output and other functions, supporting universal output interface, can quickly charge all electric vehicles.

(1) Basic structure of charging station:

Box-type electric vehicle

(1) Public parking lot: The parking lot is one of the best places for social charging stations, with convenient transportation and convenient access. You can rent a parking space with the parking lot, or even a corner location, and you can leave 2 charging spaces (because it is short-term charging, you do nt even need a dedicated charging space, you can pay a certain fee according to the number of charging vehicles).

(2) Large shopping malls: Charging stations placed here will inevitably be welcomed by shopping malls. Charging people will buy goods by the way (buy wherever you buy, just use the charging 10-20 minutes for shopping). A win-win situation.

(3) Parkable roadside: Urban parking is becoming more and more difficult. Many non-main roads are allowed to be temporarily parked. Because the box electric vehicle fast charging station occupies a small area (less than 20m ² ) There are many places for fast charging stations for box-type electric vehicles, and they can be moved at any time as needed.

(4) Expressway service area: Set up several box-type electric vehicle fast charging stations in the expressway service area to connect the surrounding cities. The number is not large, but it is of great significance. It will greatly increase the confidence of electric vehicle users.

(5) Residential area: This is the place closest to the user, although many slow speeds can be set in the community

After the electric vehicle battery is discharged, the direct current is used to pass the battery in the opposite direction to the discharge current to restore its working ability. This process is called battery charging. When the battery is charged, the positive electrode of the battery is connected to the positive electrode of the power supply, and the negative electrode of the battery is connected to the negative electrode of the power supply. The voltage of the charging power source must be higher than the total electromotive force of the battery. There are two types of charging methods: constant current charging and constant voltage charging.

Research on charging method of electric vehicle charging technology:

The conventional charging system was designed based on internationally accepted rules of thumb before 1940. The most famous of these is the "Ampere Hour Rule": the amperage of the charging current should not exceed the ampere of the battery to be charged. In fact, the speed of conventional charging is limited by the temperature rise and gas generation of the battery during the charging process. This phenomenon is of great significance for the shortest time necessary to charge the battery.

Charging station constant current charging method

The constant current charging method is a method that adjusts the output voltage of the charging device or changes the series resistance with the battery to maintain the charging current intensity unchanged. The control method is simple, but because the battery's acceptable current capacity gradually decreases with the progress of the charging process, in the later stage of charging, the charging current is mostly used to electrolyze water to generate gas and make the outgas too much. Therefore, the stage charging method is often used.

Charging station stage charging method

This method includes two-stage charging method and three-stage charging method.

The two-stage method uses a fast charging method combining a constant current and a constant voltage. First, the constant current is charged to a predetermined voltage value, and then the constant charge is changed to a constant voltage to complete the remaining charging. Generally, the switching voltage between the two phases is the constant voltage in the second phase.

The three-stage charging method uses constant current charging at the beginning and end of charging, and constant voltage charging in the middle. When the current decays to a predetermined value, it switches from the second stage to the third stage. This method can minimize the amount of air out, but it is limited to use as a fast charging method.

Charging station constant voltage charging method

The voltage of the charging power source remains constant throughout the charging time. As the battery terminal voltage gradually increases, the current gradually decreases. Compared with the constant current charging method, the charging process is closer to the optimal charging curve. Fast charging with constant voltage. Because the battery has a lower electromotive force and a large charging current in the initial stage of charging, the current will gradually decrease as charging progresses. Therefore, only a simple control system is needed.

This charging method has very little electrolytic water, which avoids overcharging the battery. However, the excessive current during the initial charging period has a great impact on the battery life, and it is easy to bend the battery plates, causing the battery to be scrapped. In view of this disadvantage, constant voltage charging is rarely used, only when the charging power supply voltage is low and the current is large. For example, during the operation of a car, the battery is charged using a constant voltage charging method.

Charging station fast charging method

Pulse charging method, this charging method not only follows the inherent charge acceptance rate of the battery, but also improves the charge acceptance rate of the electric vehicle battery, thereby breaking the limitation of the battery index charge acceptance curve, which is also a new development of the battery charge theory.

The pulse charging method first uses a pulse current to charge the battery, and then stops the battery for a period of time, and so on. The charging pulse makes the battery fully charged, and the intermittent period allows the oxygen and hydrogen produced by the chemical reaction to be recombined and absorbed in time, so that the next round of constant current charging can be performed more smoothly and the battery can absorb more Power. The intermittent pulse enables the battery to have a sufficient response time, reduces the amount of outgassing, and improves the charge current acceptance rate of the battery.

2REFLEXTM fast charging method, this technology is a patented technology in the United States, and its main charging object is nickel-cadmium batteries. Because it uses a new charging method, it solves the memory effect of nickel-cadmium batteries, so it greatly reduces the rapid charging time of the battery. The method of charging lead-acid batteries and the method of detecting the state of charge are very different from those of nickel-cadmium batteries, but they can mutually use a REFLEXTM charging method. A working cycle includes forward charge pulses, reverse instant discharge pulses, and stop Charge maintains 3 stages.

Variable current intermittent charging method. This charging method is based on constant current charging and pulse charging. Its characteristic is to change the constant-current charging section to a voltage-limited variable-current intermittent charging section. Each stage of the early stage of charging adopts the method of intermittent charging with variable current to ensure that the charging current is increased and the majority of the charging capacity is obtained. In the later stage of charging, a constant voltage charging section is used to obtain the overcharged amount and restore the battery to a fully charged state. By intermittently stopping the charging, the oxygen and hydrogen produced by the chemical reaction of the battery have time to be recombined and absorbed, so that the next round of constant current charging can be carried out more smoothly and the battery can absorb more power.

Variable voltage intermittent charging method. On the basis of variable current intermittent charging method, some people have proposed a variable voltage intermittent charging method. Different from the variable current intermittent charging method, the first stage is not intermittent constant current, but intermittent constant voltage. In each constant voltage charging stage, because it is constant voltage charging, the charging current naturally decreases according to the exponential law, which is in line with the characteristic that the battery current acceptable rate gradually decreases with the progress of charging.

Variable voltage and current wave type intermittent positive and negative zero pulse fast charging method, combined with the advantages of pulse charging method, ReflexTM fast charging method, variable current intermittent charging method and variable voltage intermittent charging method, variable voltage and current wave positive and negative zero pulse The intermittent fast charging method has been developed and applied. There are two kinds of control of pulse charging method charging circuit:

1) The amplitude of the pulse current is variable, and the frequency of the PWM (driving charge and discharge switching tube) signal is fixed;

charging station

2) The amplitude of the pulse current is fixed, and the frequency of the PWM signal is adjustable.

The pulse current amplitude and the frequency of the PWM signal are fixed, and the PWM duty cycle is adjustable. On the basis of this, an intermittent stop charging phase is added, which can charge more power in a shorter time and improve the battery's charge acceptance. ^[2]