Invest in Charger Piles or Charger Stacks?

What is Charging Piles?

EV charging piles are single devices that provide electric energy to electric vehicles. They are usually installed in public places such as public buildings, parking lots, shopping malls, and operating vehicle charging stations, as well as private places such as residential areas.

According to the charging type, charger piles can be divided into AC charging piles and DC charging piles. AC charging piles have a small charging current and a long charging time (usually 7-10h). They are slow charging and are suitable for parking spaces in residential areas and office buildings. DC charging piles are a type of charging pile mainly used for public charging, which converts AC power into DC power. The charging time is short, which is fast charging, with a charging time of one to two hours, and is suitable for public places that require fast charging.

What is Charging Stacks?

EV charging stacks are a charging group designed specifically to meet large-scale charging needs, such as large parking lots or enterprises. The charging stack can convert AC power into DC power and is equipped with multiple charging modules to serve multiple electric vehicles at the same time. It is designed to efficiently utilize power modules and reasonably allocate charging power, which can meet the charging needs of different models and improve charging conversion efficiency and equipment utilization.

Charging Pile Structure

• Power supply: The charging pile needs to be connected to a power source to provide power. The power supply can come from the power grid or from green energy devices such as solar panels.

• Control panel: The control panel is the core part of the charging pile, which can realize the control and monitoring of the charging pile. Including power calculation, automatic stop function, charging speed control, etc.

• Charging interface: The charging interface refers to the connector between the charging pile and the electric vehicle, which can exchange information and transmit power between them. There are two types of charging interfaces: DC fast charging and AC slow charging.

• Protective barrier: The protective barrier is a physical security device that can protect the charging pile and charging equipment from the external environment, such as bad weather and moisture.

• Shell: The shell is the outer packaging of the charging pile, which can protect the equipment inside the charging pile from damage by the external environment, and also plays a beautifying and decorative role.

• Support frame: The support frame is a device used to support the charging interface, usually fixed on the charging pile. The support frame can adjust the height and angle of the charging interface to adapt to different models of cars.

Charging Stack Structure

• Energy unit: This is the basic part of the charging pile, responsible for converting AC power into DC power for charging electric vehicles.

• Charging controller: Controls all aspects of the charging process to ensure the safety and efficiency of charging.

• Monitoring system: Real-time monitoring of battery voltage, current, temperature and other parameters during the charging process to ensure charging safety.

• Energy scheduling system: Manages the overall energy flow of the charging pile and optimizes charging efficiency.

• Communication system: Connects the charging pile with the cloud server to achieve remote monitoring and management, and improves the intelligence and digitalization level of the charging pile.

• Cooling system: Maintains the normal temperature inside the charging pile to prevent overheating from affecting charging efficiency and equipment life.

Charging Pile Working Principle

The working principle of the charging pile mainly involves two aspects: power conversion and transmission.

• Power conversion: The core part of the charging pile is a converter that converts grid power into DC power. The converter converts the AC power of the grid into DC power, and then transmits it to the battery of the electric vehicle through the charging cable.

• Transmission method: There are two main methods of power transmission: wired transmission and wireless transmission. Wired transmission is to transmit grid power to the battery of the electric vehicle through cables; wireless transmission is to transmit power to the battery of the electric vehicle through a magnetic field. At present, wireless transmission technology is still in the research and development stage and has not yet been widely used.

Charging Stack Working Principle

The charging stack is mainly composed of a charging module, a monitoring module, an energy scheduling module and a communication module. The modules cooperate with each other to complete the intelligent charging task. The monitoring module monitors the voltage, current and temperature of the battery module in real time, adjusts the output of the charging module according to these parameters, and ensures that the battery module on the vehicle side is safely charged. The communication module is connected to the cloud server to achieve remote monitoring and management, and improve the intelligence and digitalization of the charging pile.

The charging module is the core component of the DC charging equipment of new energy vehicles. Its main function is to convert the AC power in the power grid into DC power for battery charging. It is also the most valuable part of the charging pile industry, and its cost accounts for about 50% of the total charging pile cost.

Charging Pile Application

• Public places: As one of the main application scenarios of charging piles, public places such as parking lots, gas stations, shopping malls, etc., due to their large flow of people and vehicles, make the charging demand of electric vehicles large. Installing charging piles in public places can not only meet the charging needs of electric vehicle users, but also make positive contributions to the sustainable development of the city.

• Residential areas: residential areas such as communities, apartments and villas. Installing charging piles in these residential areas can not only provide great convenience for residents, allowing them to easily charge their electric vehicles, but also significantly improve the quality of life of residents. By deploying charging piles in residential areas, residents can avoid long journeys to find public charging stations, thus saving time and energy. In addition, this convenience can also encourage more residents to choose electric vehicles as their daily means of transportation, thereby promoting environmentally friendly travel and reducing carbon emissions.

• Office and production areas: Office and production areas such as government, enterprises, factories, hospitals, and schools are also important application scenarios for charging piles because their users or employees have electric vehicles and are permanent residents. Installing charging piles in these places not only facilitates employees or users to charge electric vehicles, but also helps meet their needs for commuting or official office production.

Charging Stack Application

• Highways, ports, airports and other important areas with dense and fast population flow: Charging piles can provide fast charging services for electric vehicles, solve the problem of electric vehicle range anxiety, and charge for 5 minutes to run 200 kilometers.

• Commercial areas: Charging piles can give full play to the role of smart charging in online car-hailing and public charging around cities. They can be fast or slow, and can be selected according to actual needs.

• Other application scenarios: Charging piles can also be used in commercial areas, residential areas, etc., and small-power piles can be used to achieve wheel charging, orderly charging, etc., and can also be combined with energy storage to achieve integrated light storage and charging.

Both charging piles and charging stacks are charging facilities for electric vehicles. There will inevitably be duplicate parts in the application scenarios, but the general direction is that charging piles are suitable for individual users or small-scale places, and charging piles are suitable for large-scale charging needs such as large parking lots and highway service areas.

Advantages of Charging Piles

• Easy to use: The charging pile takes into account the use needs of many individual users, so the installation and use of the charging pile is relatively simple and can meet basic charging needs. However, the installation process involves electrical safety, power access, ground connection and other operations. It is recommended to find personnel with professional knowledge and experience to operate.

• Low cost: Compared with charging piles, the research and development and production costs of charging piles are lower. These factors lead to a relatively low unit price of charging piles, which is more suitable for installation in parking lots, residential areas and other places.

Disadvantages of Charging Piles

• Poor compatibility: The power of the charging pile is fixed and cannot meet the charging needs of different models. When a vehicle with low power demand is connected to a high-power charging pile, it will lead to unnecessary waste of electric energy; conversely, a high-power vehicle charging at a low-power charging pile cannot fully utilize its fast charging potential, and the charging time is significantly extended. This "one-size-fits-all" charging solution limits the wide applicability and user experience of the charging pile.

• Poor adaptability: With the rapid development of battery technology, electric vehicles are constantly developing towards a high-voltage platform. However, due to the fixed power of charging piles, if you want to meet the charging needs of future electric vehicles, you can only reinvest and replace the entire pile.

• Low efficiency: Compared with charging piles, charging piles have a certain gap in charging efficiency. This is mainly because charging piles usually use more advanced charging technology and optimization algorithms, which can more efficiently manage the distribution and transmission of power and reduce energy loss. However, due to limitations in design and configuration, charging piles often cannot achieve the same high-efficiency charging level as charging piles.

Advantages of Charging Stacks

• Diversified charging needs: When a charging station needs to provide charging services for multiple different models of electric vehicles at the same time, the charging pile can adapt to various charging needs because it is equipped with charging heads of various specifications without replacing or adding additional equipment.

• High efficiency and fast charging: The charging pile uses efficient charging technology to charge electric vehicles quickly and safely, improving charging efficiency. Especially when electric vehicles are in urgent need of fast charging, the high efficiency of the charging pile can meet this demand.

• Modular design: The modular design of the charging pile makes its composition flexible, and battery cells can be added or reduced according to actual needs to adjust the amount of energy storage. This design makes the charging pile more convenient and economical when expanding and upgrading.

• Small footprint: In urban centers or areas with limited space, the modular design of the charging pile enables it to build charging stations in a relatively small space, making full use of land resources.

• Multi-channel simultaneous charging: The charging pile can support multiple channels for charging different models at the same time, improving the utilization rate and service efficiency of the charging station. In contrast, the integrated charging pile may only provide charging services for a single model, limiting its scope of use.

• Intelligent adjustment: The charging pile can realize intelligent adjustment of the output power of each terminal to meet the charging needs of different models. This intelligent adjustment function can improve charging efficiency and reduce energy consumption.

Disadvantages of Charging Stacks

• High cost: The manufacturing cost of the charging pile is higher than that of the charging pile integrated machine. First, the cable cost is high. The charging pile adopts DC power distribution, and the cable used to consider the charging adaptability of the charging pile should be thicker; second, the equipment cost of the charging pile itself is high.

• Inconvenient maintenance: If the charging pile fails, all the charging guns cannot be used, so the parking space cannot be charged normally

• The charging stack has a higher failure rate and is not as mature and stable as the integrated machine.

Although the standards such as the charging pile interface have been unified, the problem of "upward compatibility" has not been effectively solved. With the continuous advancement of battery technology, the demand for charging facilities for new energy vehicles will continue to increase. Whether the charging piles built now are suitable for future new energy vehicles has also become a major problem facing the industry.

When charging, the charging pile does not need to consider issues such as charging rate and battery capacity, and can automatically match the charging power according to the power required by the battery. In the future, when the battery energy density increases and the battery capacity increases, the charging stack can still be upgraded by replacing a higher-power charging module, thus effectively solving the problem of "upward compatibility" of the charging pile.

Charging Pile Construction Cost: an example in China

For a single charging pile, taking a 60KW single pile as an example, the equipment cost price is about 15,000 yuan (about 0.25 yuan/W), electricity, land, infrastructure, etc., the overall investment and construction cost is about 40,000-60,000 yuan.

For station construction, a 120KW DC dual-gun charging pile is selected, the price is about 30,000 yuan (about 0.25 yuan/W), and 10 units are 300,000 yuan; it needs to match a 1250kva power system, the cost of the power distribution system, if it needs to be re-applied for construction, the power plus infrastructure cost is about 800,000, and the overall investment and construction cost is about 1.1 million yuan.

Civil construction costs, including site hardening, building canopies, etc., will be determined according to actual conditions.

Site rental, the cost will vary depending on the number of parking spaces required and the geographical location.

Charging Stack Construction Cost: an example in China

The cost of the charging stack will vary depending on the number and power of the charging modules it is configured with. For example, the price of a 360kW charging stack is about RMB 98,000 (about RMB 0.27/W).

The different cable configurations of the charging stack and the charging pile may lead to cost differences.

The construction cost of the charging stack may be slightly higher due to the need for more complex power facility laying and construction costs.

Other Costs

The construction of charging stations also needs to consider other costs such as transformers, charging monitoring systems, safety monitoring, and charging metering and billing systems.

Operating costs include staff costs, maintenance costs, electricity costs, etc.

Policy Subsidies: Example in China

Policy subsidies vary from place to place, ranging from 100 yuan/kW to 900 yuan/kW.

Deployment Strategy

The construction cost of charging piles is relatively low, suitable for small-scale deployment; while the construction cost of charging stacks may be slightly higher, due to their modularity and power sharing characteristics, they are suitable for large-scale and high-efficiency charging needs.

How to Choose Charger Piles or Charger Stacks?

When choosing charging piles and charging stacks, you need to consider multiple factors to ensure that they are suitable for the relevant vehicles and usage scenarios.

1. Confirm technical specifications

• Output power: Make sure that the charging pile can provide stable power output and is suitable for the vehicle's fast charging needs. For example, a 60~120kw DC charging pile or a 7~21kw AC charging pile is normally selected for a small family car. A large vehicle that needs fast charging can also choose a 60~180kw DC charging pile or even a charging pile with a larger output power.

• Voltage and current range: Check the voltage and current range supported by the charging pile to ensure compatibility with electric vehicles.

• Charging interface standard: Select an interface that meets international or regional standards, such as CCS, CHAdeMO or GB/T, to ensure wide compatibility. It is also necessary to confirm whether the vehicle supports DC/AC charging. In the early days, a large number of vehicles on the market did not support DC/AC dual charging interface charging.

• Charging efficiency: Pay attention to the conversion efficiency of the charging pile to reduce energy loss and optimize operating costs.

2. Confirm functional characteristics

• Intelligent management: Select a charging pile that supports remote monitoring and management functions to facilitate device status monitoring and fault diagnosis.

• User interface: intuitive and easy-to-use user interface, supporting multiple payment methods, improving user experience.

• Safety features: ensure that the charging pile has multiple safety protection measures such as overvoltage, overcurrent, and short circuit protection.

• Network connection: support Wi-Fi, Ethernet or 4G connection, which is convenient for software updates and data transmission.

3. Confirm the application scenario

• Target users: clarify the main service objects in order to select the appropriate product configuration.

• Installation environment: consider the impact of the space, power supply capacity and environmental conditions of the installation site on the performance of the equipment.

• Future expansion: evaluate whether it is possible to add more charging piles and choose a system architecture that supports expansion.

• In addition to confirming the technical specifications, functional characteristics and application scenarios according to the requirements of the charging pile, the charging pile also has the following advantages:

• Power sharing: The charging pile can concentrate the power, and each charging terminal can obtain the required power from this power pile. According to the actual situation, users need to calculate how large the charging pile should be and how many terminals should be matched.

• Flexible charging: According to the charging demand issued by the vehicle BMS, the charging power is allocated on demand. The charging pile allocates power on demand and can achieve the fastest charging speed of the vehicle. However, when there are many vehicles, if the charging power exceeds the rated power, the power will be reasonably allocated and used by everyone.

• Smooth expansion: As the battery charging rate increases, the charging power demand increases, and the power of the power pile can be expanded to meet the charging needs.

• Energy saving and high efficiency: Regardless of the charging demand, the charging equipment should be guaranteed to work in the optimal load rate range.

• Adaptability: The charging pile can meet the different power requirements of various models of charging, and improve the charging conversion efficiency and equipment utilization of charging facilities.

• Compatibility: The charging pile can solve the problem of "upward compatibility" of charging piles and adapt to the needs of the rapid development of battery technology.

• When choosing charging piles and charging stacks, factors such as safety, cost, convenience and charging speed should also be considered. Be sure to choose charging equipment that meets national standards and be installed and maintained by professionals to ensure the safety and efficiency of the charging process.