Charging Methods of Electric Vehicles
Electric Vehicles are vehicles that are operated from electric motors, without using fuel mix combustion engines or gas. The power for the electric vehicle is supplied using the batteries and has to be charged when they are low. Within the next decade, usage of electric vehicles will increase according to the statistics.
In this article, I hope to briefly discuss the common ways for electric vehicles’ battery charging. There are 3 main methods :
- Conductive charging
a. AC charging
b. DC charging
2. Inductive charging
a. Static charging
b. Dynamic charging
3. Battery swap
Electric Vehicles can only store power as DC. So AC power has to convert DC. If this AC to DC converting process is done inside the vehicle, it’s known as an onboard charger. Otherwise, we called it an offboard charger.
1. Conductive charging
This is the most common charging method and it has two categories.
1.1 AC charging
Advantages:
● EV batteries can be recharged anywhere using the AC grid. (The vehicle must have an onboard EV charger.)
● EV chargers can easily communicate with the Battery Management System (BMS) without using any additional power electronic converters.
● Higher performance.
● Low cost.
Disadvantages:
● Power output is limited. (due to size and weight restrictions of the onboard charger)
● It takes a long time.
1.2 DC charging
Advantages:
● Fast-changing. ( limited only by the ability of the batteries to accept the charge.)
● Low charging time.
Disadvantages:
● Higher investment for installation.
● High power demand on the grid
2. Inductive charging
Inductive charging is known as wireless charging or cordless charging
This method uses two electromagnetically linked coils. The primary coil is placed on the road surface. The secondary coil is placed on the vehicle(bottom or top of the car)
2.1 Static charging
Advantages:
● Convenience
● Suitable for self-driving car
Disadvantages:
● High investment
● Limited space and weight of charger pad
● Relatively lower efficiency than conductive charging
● Electromagnetic radiation exposure
2.2 Dynamic charging
Advantages:
● Low stand in charging time
● Low battery
● Smaller battery size
Challenges:
● The investment cost is high
● Coil structure changes and coil misalignment on the road
● Applicability of different car types and universal coil type selection
( the dynamic inductive charging is still in the experimental stage)
3. Battery swap
The battery swap works based on switching out the depleted battery and replacing the same with a full battery. This is done automatically in a battery swap station.
Advantage:
● Battery swap can give a full charge battery without waiting a long time. (Reduce time)
● The battery charging process is done outside of the vehicle. So there is a limitation on the size, weight, and power levels of the battery charger.
● The battery can be charged by the local load and renewable energy generation.
Challenges:
● For safe handling, the vehicle must have good weight distribution. The average passenger car battery pack weight will be 250Kg-300Kg. So battery packs could be specially designed for each kind of vehicle and there must be a standard.
● In this system, the battery has to change each time when the battery swap. The consumer doesn’t know about the new battery in the vehicle. So consumers worry about it because he is in an unsure state of battery life.
● The electric connection between the battery and the vehicle carries a very high current. This connection would need to be broken each time battery exchange. That can make safety issues.
Battery Swap vs Fast Charging
● When we go to the fast charging station a battery can be charged only up to 75–80%. But from the battery swap station you can get a full charge battery with 100% state of charge.
● The fast charging required different times to charge a battery partly or fully. It depends on charging power. But the battery swap only wants battery replacement process time.
Comparison of EV charging methods
Hope all of you have gained some knowledge from this article. Sometimes in the future, more new technologies will be introduced and these things will not be used. So, hope to see you with another article soon.
