Analyzing the development trend of electric vehicle charging infrastructure and technology

Analyzing the development trend of electric vehicle charging infrastructure and technology

Electric vehicle charging infrastructure, also commonly referred to as electric vehicle supply equipment (EVSE), is a core component of a healthy electric vehicle ecosystem. It is a distribution network and dedicated power infrastructure planned for vehicle charging. Simply put, just as mobile network infrastructure is a complete communication system behind supporting mobile phone communications, electric vehicle charging infrastructure is a complete power supply control system behind supporting charging piles for vehicle charging.

The simplest EV charging station is a set of power electronics, usually wall-mounted or pedestal-mounted, that safely delivers power from the grid to the vehicle battery. Different types of chargers offer different current and voltage levels to meet the vehicle's specific battery requirements. EV chargers range from as low as 500 watts (W) to as high as 500 kilowatts (KW).

Most vehicles are equipped with an onboard charger system that converts AC power supplied by the grid into the DC power required to charge the battery. The onboard charger enables the vehicle to be charged directly from a standard household plug (slow AC) or from dedicated AC chargers available at home, work, and public places (medium AC). Chargers that supply DC power to the vehicle battery and bypass the onboard converter are called DC chargers or DC fast chargers and are capable of higher charging rates.

The charging equipment typically has some level of intelligence, responsible for user authentication, vehicle communications, data collection and monitoring, and payment. In some cases, it also has bidirectional control capabilities, allowing the dispatch system to adjust the level of power injected into the battery based on price information or other dispatch reasons. Some chargers, sometimes called "dumb" chargers, have no communication or control capabilities and simply regulate the power from the grid to the voltage and current required to charge the battery.

Hardware infrastructure for electric vehicle charging systems

A standard charging system includes the following basic hardware components:

• The power electronics component is the heart of the charging station. It provides power to the onboard battery charger of the electric vehicle.

• The charge controller is the intelligent device in the charging station that manages basic charging functions such as turning the charger on and off, measuring power usage, and storing critical real-time and event data.

• The network controller provides connectivity between the charging station and the wider network. It allows the charging station to communicate with the network using onboard telecommunications equipment so that system administrators can monitor, review and control device usage. It also manages user access to the charging station.

• A cable and connector called a charger. It plugs into the vehicle, creating a secure physical connection between the charger and the vehicle. The charger or connector typically conforms to a specific standard form factor for the automotive OEM (e.g., CCS, CHAdeMO, SAE J1772, IEC 60309).

Data Management

Electric vehicles and electric vehicle chargers continuously generate important data about the battery's state of charge, such as the battery's charge rate, the amount of electricity used in charging (kWh), price information from the power network, and demand response signals from the management system. Charging management software is designed to efficiently manage and operate charging stations and their networks. Network software can effectively facilitate the rapid deployment and configuration of electric vehicle charging systems through a two-way data flow between charging stations and their network control centers, and help operators remotely configure, manage and perform software updates. Charging management software can also set and control drivers' charging permissions, set prices, manage bills, and generate operational usage reports.

Maintenance and Service

Like any equipment used by the public and exposed to the environment, electric vehicle chargers require a certain level of service and maintenance. The service of public chargers is generally the responsibility of the charger owner or operator and is generally not a concern for power companies that do not own the charging infrastructure. However, power companies that own public charging stations should be responsible for regular service and maintenance of these assets.

The Development of Electric Vehicle Charging Technology

A few years ago, "range anxiety" was still a very unfamiliar term, but now, it is impossible not to mention it when talking about electric vehicles and their charging systems. At that time, people were worried that the car battery would not have enough energy to reach the destination, thus getting into trouble. In recent years, technological advances have greatly alleviated people's "range anxiety" about charging electric vehicles. The advancement of charging technology is keeping pace with electric vehicles and charging needs.

Next, we will briefly review the development of electric vehicle charging technology.

Battery Energy Storage

Charging at home is relatively simple, with homeowners seeing an additional charge on their electricity bill and paying it as usual. However, for companies with many employees who need to charge their cars, or companies that rely on a large number of cars, the cost of charging becomes a major issue. Battery energy storage technology provides a solution to this problem, which charges and stores batteries during off-peak hours, when demand is lower and tiered electricity prices are at a lower level. During peak energy use, such as working hours, the stored batteries take on the maximum output, which can effectively reduce the demand and impact on the grid when the load is the largest and the electricity price is the highest, thereby saving a lot of electricity expenses.

Wireless charging

It almost sounds too good to be true: being able to charge your car wirelessly like you charge your phone. The development of technology has opened up all sorts of possibilities. Unlike a smartphone, which can be placed directly on a wireless charger, a car is a behemoth that requires quite a bit of electricity to charge. This brings up environmental and cost issues. To make wireless charging of electric vehicles possible, the following conditions are required:

• Additional charger integrated in the vehicle (increases vehicle cost).

• Wireless chargers integrated in public places (the cost is quite high).

• Reduce the distance between the charger and the car to improve efficiency.

Many automotive and EVSE manufacturers, such as Genesis/WiTricity, DKE and Project STILLE (Germany), and CATARC (China) are working on automotive wireless charging technology.

Megawatt Charging System (MCS)

How to efficiently use electricity to charge the giant electric vehicles such as heavy trucks or buses and run relatively long distances is another development in electric vehicle charging technology, namely high-power charging, or megawatt charging. To make high-power charging MCS a reality, the following challenges need to be solved:

• Use larger capacity electric vehicle batteries and use thicker cables to increase charging power.

• Due to the large amounts of charge transferred, the system must be completely safe to operate.

• Make charging fast and efficient (fast charging should complete 1MW of power in 15-20 minutes).

• Fast charging stations have the capacity to charge several vehicles simultaneously.

Megawatt charging is also being used for light electric aircraft, ferries and other ships. As megawatt charging is introduced, battery storage will be essential to help cope with peak power demands on the grid.

Mobile Electric Vehicle Charging

Mobile electric vehicle charging systems include portable chargers, charging trucks or trailers, and temporary chargers. The advantage of mobile charging systems is that they do not require any permanent charging infrastructure, and the charging devices can be flexibly used where the vehicles need to be charged. This charging technology and solution is very effective for specific application scenarios, such as charging at car dealers and providing mobile charging for rescue vehicles for electric motorcycles that run out of power on the road.

Automatic electric vehicle charging

While automatic charging and wireless charging are somewhat interchangeable, the difference between them is that wireless charging typically requires intervention from the vehicle's driver, such as parking the vehicle over a charging pad. Automatic charging, as the name implies, is done completely automatically, without driver intervention.

For example, charging plates could be installed under the asphalt of roads, allowing electric buses to charge on the move, or autonomous charging plates could be installed under the asphalt of parking lots and home garages. Automatic charging is particularly important for self-driving cars, which means charging the car without the intervention of a human driver. Although it will take several years for driverless cars to travel on public roads, they are already being used in container port loading and unloading areas, and the corresponding automatic electric vehicle charging technology is being developed in parallel.

Conclusion

With the emphasis on reducing carbon emissions and achieving carbon neutrality, as well as the electrification of roads, more efficient EV charging infrastructure is bound to see rapid development. In the not too distant future, automatic and wireless charging devices may appear around us!