Introduction:
In the article "Series 3 of 'The Core of Charging Piles and Beyond'—Electric Vehicle Power Battery and Its Charging/Discharging Principles: AC Charging Pile or DC Charging Pile?", we briefly mentioned the differences between DC and AC charging piles. This article will summarize DC charging piles from the following five aspects, aiming to exchange ideas with industry peers!
1. What is a DC charging pile?
2. Classification of DC charging piles
3. Relevant standards for DC charging piles
4. Basic composition and working principles of DC charging piles
5. Development trends of DC charging piles
(1) Ultra-high-power charging stacks - dynamic power allocation - flexible charging
(2) Smart circular charging for community parking lots
(3) Wall-mounted home charging piles entering home appliance stores and households
(4) Integrated "solar charging and storage" system
(5) Shared charging and free charging
The article raises 11 technical questions about charging pile design, which may interest technical practitioners in the charging pile industry:
1. Can the output end of the charging module group use only one fuse? Can only one DC contactor be used?
2. Can DC contactors be controlled directly by the controller’s I/O signals without relays?
3. If a leakage switch is added to the input end of the auxiliary power supply, can it be omitted? If no leakage switch is added to the three-phase AC input end, is this acceptable?
4. Can the fan be controlled without relays?
5. Can two auxiliary power supplies be merged into one?
6. Can only one type of 12V auxiliary power supply be used?
7. Can the electronic lock be engaged without relays?
8. Is it acceptable that the diagram lacks voltage and current detection units?
9. The electricity meter collects voltage and current information, the BMS also collects voltage and current information, and each charging module itself reports voltage and current information to the charging controller. What are the differences among these?
10. A 120-ohm resistor is connected to the overall terminal of the charging module group. Should a 120-ohm resistor be matched at the CAN output interface of each module within the charging module?
11. How many CAN communication ports and RS485 communication ports are used in total in the diagram? If it is a dual-gun system, how many CAN communication ports are required?
1. What is a DC charging pile?
The author has not verified the origin of the term "DC charging pile." In some national and industry standards, similar terms include "off-board charger," "off-board conductive charger," "conductive charging system," and "battery electric vehicle DC charging system." The term "pile" might not sound very formal, but in the domestic industry context, people are accustomed to calling it "DC charging pile" instead of "DC charger" or "off-board charger." The term "on-board charger" has become a fixed term and aligns with the international term "On-board Charger."
In the industry standard issued by the National Energy Administration, "NB/T33001-2010: Technical Conditions for Off-board Conductive Chargers for Electric Vehicles," the term "off-board charger" is defined as follows:
Off-board charger: A dedicated device fixed on the ground that converts grid AC power into DC power to charge the power batteries of electric vehicles through a conductive method. (The use of the term "power battery" in this standard may feel uncomfortable due to its age.)
In the highly scrutinized national standard "GB/T18487.1-2015: Electric Vehicle Conductive Charging System Part 1: General Requirements," there is no specific definition for the term "off-board charger," but the term "charging" is defined. This definition feels awkward and like a direct translation from English:
Charging: Adjusting grid (power supply) AC or DC to a calibrated voltage/current to provide power for the power battery of an electric vehicle, and optionally powering on-board electrical equipment.
DC charging piles, commonly known as "fast chargers," as the name suggests, can quickly charge electric vehicles. Tesla has named its model "SuperCharger," which translates to "super charging pile" in Chinese. Abroad, "SuperCharger" seems to have become synonymous with DC charging piles. The author has seen ABB’s new product press releases titled "SuperCharger."
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