How #1 charging pile works
The alternating current is input from the three-phase power grid and converted into direct current through the bridge uncontrollable rectifier circuit . After being filtered by the LCR circuit, it is sent to the high-frequency DC-DC power converter. The power converter outputs the required DC voltage after direct-to-direct conversion . The output is filtered to charge the electric vehicle battery. There are four charging modes available: fixed quantity, fixed time, fixed amount, and automatic (until full).
Electric vehicle charging structure diagram
In summary, the working principle of the charging pile can be summarized as using the power supply , converter and output device to combine to change the voltage from low to high, convert the high voltage into a state that can provide power supply, and finally achieve charging of electric vehicles.
#2 Classification of charging piles
Charging piles are divided into AC charging piles and DC charging piles. The former is also called “slow charging” and the latter is also called “fast charging”.
(1) AC charging pile
The AC charging pile is a power supply device that is fixedly installed outside the electric vehicle and connected to the power grid to provide AC power for the on-board charger (that is, the charger fixedly installed on the electric vehicle).
AC charging piles only provide power output and have no charging function. They need to be connected to a car charger to charge electric vehicles. It is equivalent to just playing a role in controlling the power supply.
AC charging is divided into single-phase AC and three-phase AC according to the number of AC charging phases; according to the power of AC charging, there are 2KW, 3.3KW, 7KW, 11KW, 22KW and other AC charging. The most commonly used is the household single-phase 220V 7KW charging pile.
The 7KW AC charging pile mainly consists of a pile body, LED indicator board, LCD display, card reader, auxiliary power supply, main control module, relay module, wiring strip, single-phase circuit breaker (air switch ), surge protector (anti- Lightning device), smart meter, AC contactor, access control switch, emergency stop switch, charging gun, charging harness, etc. (At this stage, single-phase 220V 7KW charging guns all have 7 holes and 5 contact terminals . Only high-power charging guns such as three-phase 380V 22KW charging guns are equipped with 7 full contact terminals.)
(2) DC charging pile
The DC charging pile is a power supply device that is fixedly installed outside the electric vehicle and connected to the AC power grid. It can provide DC power for the off-board electric vehicle power battery. The input voltage of the DC charging pile adopts three-phase four-wire AC 380 V ±15%, frequency 50Hz, and is rectified by internal control. The output is adjustable DC, which can directly charge the power battery of the electric vehicle. Common powers are 30KW, 60KW, 90KW, and 120KW.
A 60KW charging pile generally consists of an LED indicator board, LCD display, card reader, rectifier (two 30KW), wireless network module, switching power supply, main control board, anti-reflection board, electronic lock, fuse, ammeter , (A+) Air switch, leakage circuit breaker, lightning arrester, single-phase air switch, shunt, cooling fan, etc.
According to the installation location, installation method, and number of charging guns, it can be divided into:
#3 Parts you should pay attention to when purchasing charging piles (1) Charging pile columns
Floor-standing charging piles generally require upright columns. The pile structure is usually made of steel, aluminum alloy and other materials, which has strong durability and stability.
(2)Charging module
The charging module is the core part of the charging pile, including chargers, controllers, power supplies and other components. The charger is the main component of the charging pile and is responsible for converting electrical energy into the electrical energy required by electric vehicles. The controller is responsible for controlling the working status of the charger and various parameters during the charging process to ensure the safety and stability of the charging process. The power supply provides electric energy to the charging module.
1. Microprocessor module
The microprocessor is one of the core components of the AC pile motherboard. It can process commands from the user and control the operation of the AC pile accordingly. This module includes the central processing unit (CPU), memory, clock, and other necessary integrated circuits.
2. Communication module
The communication pile needs to communicate with the backend server and mobile terminal. The communication module can provide various interfaces, such as Ethernet, RS485, community network, etc. This module is mainly responsible for transmitting communication pile data to the backend server or mobile terminal to achieve remote monitoring and management.
3. Charging control module
This module is connected to other electronic components on the AC pile motherboard to control the entire charging process. It is responsible for identifying vehicle models, confirming charging needs, determining appropriate charging methods and charging power, and monitoring various parameters during the charging process, such as charging current, voltage, etc.
4. Safety protection module
In the AC pile mainboard, the safety protection module is responsible for ensuring the safety and reliability of the charging process. It can detect data such as battery power, voltage and temperature during charging , and ensure the safety of vehicles and users during charging through system control. Including leakage protection, overcurrent protection, overvoltage protection, etc.
AC contactor circuit schematic diagram
5. Sensor module
The sensor module can collect various data on the environment where the AC pile motherboard is located, such as temperature, humidity, combustible gas concentration, etc. These data can be used to optimize the use efficiency of AC piles and ensure the safety, reliability and efficiency of the entire charging process.
(3)Display screen
The display screen of the charging pile is usually used to display information such as the status of the charging pile, charging progress, charging fees, etc. There are different types and sizes of display screens. Some charging piles are also equipped with touch screens to facilitate user use, realize human-computer interaction, and meet the personalized needs of different types of users.
(4)Account management module
The accounting management module calculates the consumption amount based on the current real-time electricity price and consumed electricity data, collects fees, and prints bills. Completing accounting management tasks requires the cooperation of the controller and the embedded printer. The charging pile adopts a trapezoidal electricity price policy. The controller calculates the consumption amount and completes the charge. The printer communicates with the controller. The controller sends the consumption information to the printer and prints the bill details of this charging.
(5)Connect the cable to the charging gun
The connecting cable is the bridge between the charging pile and the electric vehicle, responsible for transmitting power and data. The quality and length of the connecting cable directly affects charging efficiency and safety. Some high-end charging piles are also equipped with automatic cord reels for user convenience.
The main function of the charging gun is to connect to the car charging interface to charge the car. The AC pile charging gun has 7 holes according to the current new national standard. The charging pile mainly contains three parts: charging gun terminal base, charging gun and charging gun base.
1. Charging gun terminal block: Connect to the charging pile, fix the charging gun wire body, and then connect the charging gun to the charging pile shell.
2. Charging gun: Connect the charging pile and car charging port to charge the car.
3. Charging gun holder: where the charging gun is placed when it is not charging.
The design and manufacturing quality of the above parts directly affect the service life and safety of the charging pile. Therefore, you need to pay attention to these aspects when purchasing a charging pile.
#4 Charging pile engineering composition and engineering interface
Charging pile engineering components are generally divided into charging pile equipment, cable bridges and optional functions.
(1) Charging pile equipment
Commonly used charging pile equipment include DC charging pile 60kw (floor-standing double gun), DC charging pile 30kw (floor-standing single gun), AC charging pile 7kw (wall-mounted single gun), AC charging pile 7kw (wall-mounted double gun) and AC Charging pile 7kw (floor-standing single gun);
AC charging piles are often equipped with components such as leakage protection switches, AC contactors, charging guns, lightning protectors, card readers, meters, auxiliary power supplies, 4G modules, and displays;
DC charging piles are often equipped with components such as switches, AC contactors, charging guns, lightning protectors, fuses, meters, DC contactors, switching power supplies, DC modules, 4G communications, and displays.
(2) Cable tray type
Mainly distribution cabinets , power cables, electrical wiring, electrical piping (KBG pipes, JDG pipes, hot-dip galvanized steel pipes), bridges, weak current ( network cables , switches , weak current cabinets, optical fiber transceivers, etc.).
(3) Optional functions
It mainly includes changing the AC charging pile plastic shell to a metal shell, adjusting the length of the charging gun cable, 4G network communication, changing non-touch to touch screen, backend management system (including hardware support) operation and maintenance update costs, APP software ( including hardware ) Support) and display size upgrade, etc.
Currently, according to the Power Supply Bureau’s requirements for power supply property rights management, the construction scope of the charging pile project can be divided as follows:
(1) From the high-voltage power distribution room to the charging pile power distribution room, the power distribution room to the charging pile partition main box, and the partition main box is connected to the charging pile meter box, this part of the circuit contains high and low voltage cables , high and low voltage equipment, transformers , and power distribution The supply and installation of boxes and meter boxes are carried out by the power supply unit;
(2) The charging pile equipment and the cables behind the charging pile meter box are constructed by the charging pile manufacturer;
(3) The time for detailed drawings of charging pile locations in various regions is uncertain, resulting in the inability to configure the piping from the charging pile meter box to the charging pile on site. This part can be divided according to the site conditions, and the piping and wiring can be constructed by the general contractor or by the charging pile. Manufacturer’s exposed pipe and wiring construction;
(4) The bridges for charging piles, as well as the basic grounding and trenches in the charging pile power distribution room will be constructed by the general contractor.
#5 Charging pile cost survey
Charging pile equipment and installation prices
The installation price of charging pile equipment is basically 60-85 yuan/unit. The price of DC charging piles in the equipment is much higher than that of AC charging piles. Project A, Project B, Project C and Project D are ranked according to the construction time in 2020 and 2020 respectively. , 2021 and 2022, and because there are more and more manufacturers on the market, there are more and more brand choices, the price is gradually falling, and because Project D has signed a centralized procurement contract with relevant manufacturers, the price is relatively lower.
Cost analysis of preliminary preparation projects for charging pile projects
