What aspects does the design of electric vehicle charging stations involve?

As a frontline designer, I work on EV charging piles daily. Amid worsening global climate change and China’s rapid economic growth, green mobility like e - bikes and electric cars has boomed, yet charging issues have become a focal concern. The risky “Bypass Wire” charging has spurred huge demand for professional piles. Having taken part in the CNPC First Construction residential charging pile renovation, I’m sharing my hands - on experience.

I. Industry Context
(1) Electric Vehicles: Tech - Driven Evolution

Today’s EVs, from e - bikes/tricycles to electric cars, all use AC charging piles. Battery tech advances – higher energy density from R & D, lithium - ion/solid - state batteries, fast - charging breakthroughs – plus smart driving and vehicle - to - network tech (enabling auto - drive, cruise control, remote monitoring, etc.) have transformed EVs.

(2) Charging Piles: Booming Market

Split into AC/DC (AC is more common), China’s charging pile market has exploded, reaching 10.804 million units by July 2024. They’re deployed centrally (for large lots, transit) or decentrally (for small lots, communities). I focus on low - power decentralized AC piles, which supply power to on - board chargers (converted to DC).

II. Charging Pile Design: From Standards to Custom Builds
(1) General Requirements: Safety, Function, Installation

Layout must consider power, fire, flood infrastructure. Locate piles for easy power access, away from hazards, in low - dust, non - corrosive areas (or downwind if needed). Avoid vibrations, ensure traffic access, and keep a ≥40cm safe distance from structures for maintenance.

Functionally, interfaces follow unified standards for universal compatibility. Multiple power options, efficient conversion, anti - interference, remote monitoring, fault diagnosis (with alarms/info upload), and diverse payments (WeChat/Alipay/cards) are needed.

Installation: Floor - mounted piles need a 0.2m - high foundation (≥0.05m larger than the pile) for shed - less areas. Wall - mounted piles attach vertically to walls, operable height, usable with/without sheds.

(2) E - Bike Piles: CNPC First Construction Project

Pre - renovation, “flying lead” charging was risky. We designed piles for e - bikes, adding them at unit entrances (shed - less communities like Zhongyou Garden) or in sheds (e.g., Zhongyou Huayuan).

Power Distribution: Circuits serve 6–8 piles, using WDZ - BYJ (F) - 0.8/1KV - 3×6 mm² wires (protected by steel pipes to distribution boxes, connected to upper - level standby circuits). TN - S grounding: floor - mounted piles connect to the main grid, wall - mounted piles (and sheds) ground via 40×4 galvanized flat steel. Each pile supports ≤1200W e - bikes, with single - phase sockets in sheds. Cables (0.6/1kV copper - core) and wires (halogen - free, flame - retardant) use PVC troughs/pipes indoors, direct burial outdoors (with galvanized steel pipes for building entry, sealed to prevent water). Floor - mounted piles go in unit - entrance open spaces; wall - mounted ones on unit walls (0.7–1.1m height, uniform per community, 1.2–1.5m spacing).
Selection: Each socket has a 220V/10A/50Hz, 2.0% - accuracy static energy meter (storing 2 settlement periods’ data, protected from loss/tampering). Piles record charge start/end, power before/after (reset to zero post - charge), with card/QR code payments and IP54+ protection (load/short - circuit/leakage protection).

(3) Electric Car Piles: Parking Lot Renovation

Decentralized AC piles are added (1 per car space) for easy management, positioned for convenience.

Power Distribution: 6.8kW/220V piles use circuit breakers (short - circuit/residual current protection, no shared breakers). High - quality cables/wires ensure voltage compliance. A complete grounding system (with equipotential wiring) ensures safety.
Interface: Standard - compliant, dust/water - resistant, universal for all EVs.
Control Circuit: Precise current/voltage control (damage - free, smart mode - switching, over - charge/short - circuit protection).
Metering/Billing: Accurate metering, flexible billing (adapting to needs/time), with data management for users/operators.

III. Load Calculation: Critical for Planning

For decentralized AC piles, determine pile specs, calculate via formulas (1)/(2), and use Table 1’s demand coefficients. This ensures a rational power distribution design.

In formulas (1) and (2),

S js

represents the calculated capacity of the charging equipment (in kVA);

P 1

P 2

, and

P 3

represent the total rated power of various types of charging equipment. Generally, the load grouping and classification are carried out according to single - phase AC charging piles, three - phase AC charging piles, off - board chargers, etc. (in kW); P_$1$, P_$2$, and P_$3$ represent the working efficiency of various types of charging equipment, generally taken as 0.95; cosφ

1

, cosφ₂, and cosφ₂ are the power factors of various types of charging equipment, generally greater than 0.9;

Kt

is the coincidence factor, generally taken as 0.8 - 0.9;

K

is the demand factor, as shown in Table 1.

Conclusion

As public environmental awareness rises and EV technology advances, EVs, with longer ranges, lower costs, and better cost - effectiveness, will enter millions of households. Charging piles, crucial EV infrastructure, are increasingly adopted. With government - enterprise collaboration, massive charging pile construction in public/private parking lots, garages, communities, and stations is inevitable. Thus, standardized design, use, and scientific management of charging piles are vital. This paper, using real projects, summarizes the electrical design of non - motorized and motorized vehicle charging piles, offering references for similar future projects.