Understanding Electric Vehicle Charging Piles: Common Indicators and Functional Descriptions

Common indicators and functional descriptions of electric vehicle charging piles

[Simple principle

Before explaining the various indicators, it is necessary to briefly understand the technical principles of the charging pile.

 

From the external structure, the charging pile is clearly divided into components such as the pile body, cable, and charging gun head.

 

At first glance, it seems that the charging pile performs the charging work, but for the AC charging pile, the real charging process is completed by the on-board charger (OBC) built into the car.

 

After the charging gun head is inserted into the slow charging interface of the car, the AC charging pile sends the AC power to the on-board charger, which converts the AC power into DC power and cooperates with the car battery management system (BMS) to complete the battery charging.

 

Therefore, the AC charging pile can be understood as a set of connection and control equipment with a protection system. It implements a unified electrical protocol (national standard regulations) to communicate with the on-board charger to achieve functions such as opening and closing the scheduled charging. And it has various protection functions, such as overvoltage, overcurrent, lightning protection, temperature control, etc.

 

In addition, there are peripheral control functions such as Bluetooth, WIFI, 4G communication operation mode, operation sharing, etc.

 

Therefore, in addition to functional differences, the most important factor that determines the quality of AC charging piles is quality, which is mainly determined by the quality and workmanship of the plate, wire and spare parts, and is directly reflected in the standard levels of performance and safety protection.

 

Of course, there are also service links such as installation, warranty and after-sales.

 

DC charging piles do not use on-board chargers, but their own charging modules communicate with the vehicle. The technical scope and requirements are different.

 

But the factors that determine quality are similar.

 

[1]. Power and compatibility

 

The power of a charging pile refers to the maximum amount of electrical energy that can be output per hour, in kW or "kilowatts".

 

AC charging piles are generally divided into 3.5kw, 7KW, 11kw, and 22KW specifications according to power.

 

The more precise definition of the 7KW specification is 220V/32A/7kw, which is also the most common specification at present.

 

Charging piles above 7kw require a 380V meter.

 

As mentioned above, the choice should be based on the power of the vehicle's own charger, while considering expansion needs such as changing vehicles.

 

The mainstream new energy vehicle brands now all support 7KW charging piles.

 

For example, if the battery pack of a car is 56 degrees (KWH), the 7KW charging pile is nominally charged at 7 degrees per hour.

 

Theoretically, 56/7 = 8, that is, 8 hours to fully charge. It can be fully charged overnight.

 

The current vehicle model information generally indicates the fast charging and slow charging time. Slow charging refers to the time of using an AC charging pile.

 

Of course, the actual charging efficiency will fluctuate. (For more information, please refer to: [7-9] Charging power fluctuation and loss)

 

The 22kw charging pile is backward compatible with 11kw, single-phase 7kw, and 3.5kw models, and has strong adaptability.

 

In addition, because of the high power, its device and wire design specifications are higher and safer. Of course, the price is also higher.

 

So if you have two cars at home, or consider future expansion, you can consider choosing a 22KW charging pile.

 

In short, you must choose a charging pile that is not less than the power of the on-board charger and is compatible.

 

Note that charging piles above 7kw require a 380V meter.

 

[2] Safety protection

Current mainstream brands of AC charging piles have all achieved basic safety protection.

 

Whether the advertisements claim that they have 8, 10 or more layers of protection, they are actually all lightning protection, short circuit protection, leakage protection, current protection, voltage protection, over-temperature protection, flame retardancy and other aspects.

 

In addition, you can also check whether there are functions such as automatic power off after full charge, emergency one-button emergency stop button, fuse alarm, and device offline alarm.

 

There are separate national standards for dust and water resistance, see the chapter introduction

 

In addition, some brands have passed IK10 shell anti-collision tests.

 

The IK code indicates the shell's protection level against harmful mechanical collisions from the outside world, with a number from 01 to 10, with the highest being 10.

 

(That is, the shell can withstand more than 20J of energy 5 times, and the same point cannot be impacted more than 4 times)

 

DC charging piles have higher safety performance requirements such as electrical safety, mechanical structure safety, and lightning protection and anti-static protection, which are omitted in this article.

 

[3] Waterproof and dustproof level

Waterproof and dustproof are based on the special unified IP dustproof and waterproof level test standard. It is measured by a third-party testing agency.

 

The protection standard required for charging piles in my country is no less than IP54 for charging piles installed outdoors, and no less than IP32 for charging piles installed indoors.

 

Explanation: The first digit after IP is the dustproof level, and the second digit is the waterproof level. The larger the number, the higher the protection level.

 

Dustproof level 5 means: it cannot completely prevent dust intrusion, but the amount of dust intrusion will not affect the normal operation of the product.

 

Waterproof level 4 means: it prevents splashing water intrusion and splashing water from all directions.

 

All products on the market can now meet or exceed the IP54 standard. Good products will even meet the standard of IP65 or higher for the gun head.

 

So if your charging pile is installed indoors, such as in an underground parking lot, you don’t need to pay too much attention to this.

 

However, if it is installed outdoors, my suggestion is: the gun head must be IP 65 or above, and if conditions permit, the charging pile body should be equipped with a protective box.

 

[4] Gun head and gun wire

As the charging connector and the most frequently used gun head, the quality and workmanship are undoubtedly extremely important.

 

After using some charging gun heads for a few years, you may find that the temperature is getting higher and higher during charging. One reason is that the metal coating of the electric needle in the gun head is worn and consumed, which will also affect the charging efficiency. Therefore, some brands now treat the gun heads with silver plating.

 

From the perspective of injection molding technology, if it is a one-time injection molding, the physical properties are generally better and more stable, and the quality is more stable.

 

In addition, if there is a quality problem in the circuit control, it may cause the gun to jump and lock.

 

The gun wire directly connected to the gun head is also very important. After all, it is several meters long and directly affects the charging effect. It is also a safety factor.

 

Now the gun wires of mainstream brands are all 6 square specifications (3 cores or 5 cores depending on the voltage used), and the difference is not big.

 

Some will be marked as fluorine-free or oxygen-free pure copper wire (stable, corrosion-resistant and flame-retardant), which is of course better.

 

[5] Shell

The material and workmanship of the shell are easily overlooked. In fact, there are differences between manufacturers and even between different products of the same manufacturer.

 

If the charging pile is placed outdoors, pay special attention.

 

The most common ones are PC/ABS and PC/ASA

 

Here is a simple conclusion: PC/ASA has better flame retardancy and is more impact-resistant.

 

[6] Charging start/control method

In addition to the completely unlimited plug-and-play method, there are three common control methods:

 

1. Card swiping (physical method)

 

This is the most basic method and is also provided. Simple and effective.

 

2. Short-distance remote control method

 

Bluetooth connection, or built-in WIFI connection.

 

In this way, after the mobile phone is connected to the charging pile within a few meters, it can be controlled through a specific APP or browser page.

 

3. Remote network control

 

The charging pile has a built-in 4G SIM card, and then connects to the Internet through traffic, so that users can remotely control it through APP and mini-programs, which is more convenient.

 

The 4G version of the product that you usually see has this function, of course, the price is higher.

 

For some charging piles that support operation charging functions, this is a must-have function.

 

This function may be subject to the following restrictions: first, there must be a network signal, and different manufacturers may choose different networks such as China Telecom or China Mobile. Therefore, if it is installed in an underground parking lot, you must first test whether there is a corresponding 4G signal.

 

In addition, traffic is charged, and some manufacturers will provide traffic for several years.

 

For the above three types of control methods, the support level of charging piles of different manufacturers varies. Choose according to your needs.

 

[7] Appointment charging

This function must be available.

 

First, it is convenient and saves time.

 

Second, it is economical. Reasonable setting of charging time and making full use of the low price of off-peak electricity at night can save more money in the long run.

 

Another point is that when the temperature is low, cold start will affect the performance of new energy vehicles such as endurance. Pre-charging can heat up key components such as the battery in advance, which can improve endurance performance and also protect the vehicle from preheating.

 

[8] Information display screen

Some charging piles are equipped with information display screens, which can display information such as voltage, current, real-time power, temperature, charging time, etc.

 

Some can also display the working status of each phase of the three-phase charging pile.

 

These display information are helpful for understanding the charging status and preliminary fault location when problems occur.

 

For example, when the charging power is found to be reduced, there may be many reasons, such as unstable voltage.

 

The voltage input from the meter actually fluctuates within a range. For example, 220V AC power may actually fluctuate within the range of 200V-250V. This will of course affect the current change and the charging power.

 

With the above specific information display, it is possible to preliminarily determine whether the input voltage is unstable or the problem is with the vehicle's own components.

 

Of course, many charging piles now do not have information display screens. Instead, they are displayed and controlled on the APP, and the effect is the same.

 

[9] Warranty and after-sales service

The technical differences between charging piles are not that big. The quality of many electrical materials and processes is not something that ordinary consumers can quickly distinguish. Therefore, after-sales service guarantees and warranty periods are also indirect factors in measuring their quality and brand.

 

After the warranty period has expired, the repair cost of many charging pile products will be high.

 

Common brands provide a 1-year warranty, and some offer a 2-year or 5-year warranty, which is even better.

 

[10] Certification

Certification by an authoritative organization is of course one of the best ways to prove product quality.

 

The common certifications for charging pile products now include:

 

CQC certification

 

CQC is the China Quality Certification Center. It inspects products according to national standards in various aspects. Certificates will only be issued if they meet the national standards. Moreover, CQC re-inspects and renews the certification every year.

 

Therefore, charging piles with CQC certification are all reliable products.

 

CE certification

 

CE certification is a series of regulations formulated by the European Union (EU) on product safety and quality, requiring that products sold to the European market must comply with specific directive requirements.

 

UL certification

 

The UL certification in the United States is a safety test and certification conducted by Underwriter Laboratories Inc.

 

TUV mark

 

It is a safety certification mark customized by the German TÜV for component products and is widely accepted in Germany and Europe.

 

Manufacturers that export products overseas generally pass the above-mentioned European and American market certification.

 

So are those without certification necessarily unreliable? Not necessarily. If it is a large brand manufacturer, its quality standards are often higher than the national standard (CQC certification).

 

[11] Shareable/operable

Now many manufacturers have launched shared/operable charging pile products. That is, in addition to using the charging pile yourself, you can share it with others and charge a certain fee.

 

For example, Xingxing Charging can set the price and time period of your charging pile through the APP, and then join the Renren Power Station platform. Other car owners can search for your charging pile through the APP and then drive their cars to your charging pile to charge.

 

Teledian also has a dual-pile product that can be shared by scanning a code, which is displayed on the Teledian charging map.

 

Some other brands also have shared DC charging piles.

 

However, such services generally require the signing of an operating agreement and the payment of some fees every year.

 

This type of product is actually not very meaningful for most individual users, because when sharing your own private charging pile with others, you need to consider many factors such as parking space occupancy, entry and exit of the community, the relationship between pricing and charging pile depreciation, and the energy consumed for maintenance.

 

This type of product is more suitable for providing public charging services in communities, enterprises and institutions, homestays, hotels and public places. And generally, high-power DC piles should be used.

 

This part will not be introduced in detail in this article.

 

[12] Appearance

Appearance is a differentiated requirement and a subjective factor.

 

Some car owners do not care about the appearance at all, while some car owners may choose a certain product just for the appearance.

 

The appearance of each generation of products produced by the manufacturer is also very different.

 

So I will not analyze it. Just like it.

 

[13] Others

One-button emergency power off.

 

Locking the car means locking the gun. After locking the car, the charging gun cannot be pulled out and needs to be unlocked. The vehicle needs to support the locking function.

 

Automatic power off when fully charged.

If you Want to know more,Welcome to contact us, website：www.jubilee-energy.com

email: vivi@jubilee-energy.com or WhatsAPP +86-18824552258

 

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