With increasing global focus on environmental protection and sustainable development, electric vehicles (EVs) are becoming a popular transportation choice. EV charging infrastructure is also gaining attention. So, how does EV charging work? This article will explain the principles, steps, and factors affecting EV charging in detail.
1. What is EV Charging?
EV charging is a key part of the EV industry. It is closely linked to the development of EVs. It replenishes the battery of an EV. This allows drivers to power the vehicle and travel long distances. It helps break free from dependence on fossil fuels. The EV charging infrastructure consists of various types of charging stations. It plays a crucial role in promoting the widespread use of EVs. It ensures smooth charging for EV owners at home, work, and public places.
2. How Does EV Charging Work?
2.1 The Working Principle of EV Chargers
2.1.1 AC Charging
Input and Conversion: An AC EV charger is usually connected to an AC power source at home or a business. It draws AC power from the grid and then sends it to the EV.
Onboard Charger: Inside the EV, there is an onboard charger. It converts AC power to DC power. This is done by a rectifier. The rectifier changes the sine wave of AC power to the pulsating wave of DC power.
Battery Charging: The converted DC power is then delivered to the EV’s battery pack. It charges the battery. The charging current and speed depend on the onboard charger’s power and the battery’s ability to accept a charge.
2.1.2 DC Charging
Direct Power Supply: A DC EV charger gets AC power from the grid. It converts AC to DC power inside the station. This skips the AC-DC conversion in the EV. So, it can provide higher charging power.
Fast Charging: DC charging stations usually have much higher power than AC ones. They can charge EVs quickly. For example, some fast-charging stations on highways can charge an EV’s battery to about 80% in 30 – 60 minutes.
Battery Management System: During charging, the DC charging station communicates with the EV’s battery management system. The system monitors the battery’s voltage, current, temperature, and so on. It ensures safe and efficient charging.
2.2 The Steps of EV Charging
2.2.1 Finding a Charging Station:
You can use a mobile app to find nearby charging stations. The app shows location, status, and charging type. You can also use the car’s navigation or map app. In some cities, maps mark the locations of charging stations.
2.2.2 Connecting the Charging Equipment:
Based on the car’s charging port type, choose the right charging gun. Plug it into the port securely. Then start the charging station by swiping a card, scanning a code, entering a password, or using a mobile app.
2.2.3 Starting the Charging:
You can set the charging amount or time on some charging stations. For example, charge to 80% or for 1 hour. During charging, you can check the progress on the charging station’s screen or a mobile app. Also, watch the indicator lights to make sure charging is normal.
2.2.4 Ending the Charging:
When the battery is full or reaches the set amount, the charging station stops automatically. You can also stop it manually in advance. After charging, unplug the charging gun and put it back in the designated place. Keep the plug and port surfaces dry and clean.
3. Factors Affecting EV Charging
3.1 Charging Infrastructure
Chargers are divided into three levels. Level 1 chargers use 120V AC. They are suitable for slow charging at night. Level 2 chargers use 240V AC. They have a moderate charging speed and are suitable for daily use. Level 3 chargers provide DC power. They can charge quickly but are more expensive. The current capacity of the charging cable affects the charging speed. It needs to match the charger’s power and the vehicle’s charging capacity. In shared charging stations, the load management system allocates power. When multiple vehicles charge at the same time, the charging speed of each vehicle will slow down.
3.2 The Vehicle Itself
The larger the battery capacity, the longer the charging time. When the battery has less power, it charges faster. But when it is close to full, the charging speed will slow down to protect the battery. The onboard charger converts AC to DC. It determines how much charge the vehicle can accept at a time. The battery management system controls the charging rate. It prevents overcharging or overheating. It ensures safe charging and extends the battery’s life.
3.3 Environment
Extreme temperatures affect charging speed. In cold weather, the battery’s internal resistance increases. The battery needs to be heated before charging. In hot weather, the vehicle may limit the charging speed to prevent battery damage. The local power grid or home wiring may not support high-speed charging. Houses may need to upgrade their circuits to meet the needs of high-power charging.
3.4 Other Factors
Using the car’s air conditioning, lighting, and other systems during charging will consume some of the charging energy. This will extend the charging time. Lithium-ion batteries have a limited lifespan. Over time, their charging capacity and fast-charging ability will decline.
4. Summary
The realization of EV charging is the result of the interaction of many factors. The efficient operation of the charger relies on the strong support of the charging infrastructure. It also needs the precise cooperation of the vehicle’s charging system. The smooth progress of the charging process is also constrained by many external factors, such as environmental conditions. Only by deeply understanding the interrelationships between these factors can we better optimize the charging process. This will improve charging efficiency and provide strong support for the widespread use and sustainable development of EVs.
