Types of Electric Vehicle | Electric Vehicle | Detail Report

EVS can be categorized as follows:

1. Battery Electric Vehicle (BEV)
2. Hybrid Electric Vehicle (HEV)
3. Plug-in Hybrid Electric Vehicle (PHEV)
4. Fuel Cell Electric Vehicle (FCEV)

1. Battery Electric Vehicle (BEV):

Definition:

• EVS with only batteries to provide power to the drive train are known as BEVs.
• BEVs depend solely on the energy stored in their battery packs. Therefore the range of such vehicles depends directly on the battery capacity.

Basic Configuration of BEVs:

• Fig. shows a basic configuration for BEVs.

Fig. BEV configuration

• The wheels are driven by one or more electric motors, which are powered by the batteries through a power converter circuit.
• The battery’s DC power is converted to AC by inverter and applied to run the ac motor.

Range of BEVS:

• Typically their range varies from 100 km to 250 on one charge, whereas the top-tier models can have a range from 300 km to 500 km.
• These ranges depend on the following factors:

1. Driving condition and style.
2. Vehicle configurations.
3. Road conditions.
4. Battery type and age

Recharging:

• The depleted battery pack needs charging why takes quite a lot of time as compared to refueling a conventional ICE vehicle.
• Recharging can take as long as 36 hours to completely replenish the batteries.
• Some batteries take far less time than we but none is comparable to the little time required to refill a fuel tank.
• The recharging time depends on factors such as the charger configuration, its infrastructure operating power level.

Advantages of BEVS:

The advantages of BEVs are as follows:

1. Simple construction, operation, and convenience.
2. These do not produce any greenhouse gas.
3. They do not create any noise.
4. They provide instant and high torque, even a low speeds.
5. The BEVS are perfect vehicles for urban driving which requires running at slow o medium speeds, and these ranges demand a low torque.

Disadvantages of BEVs:

The disadvantages of BEVs are as follows:

1. They have a limitation of range.
2. This makes them the perfect vehicle to use in the urban areas only.

2. Hybrid Electric Vehicle (HEV):

Definition:

• HEVs are electric vehicles that use both an ICE and an electrical power train to power the vehicle.
• The combination of these two can come in different forms.

Principle of operation:

• HEVs are primarily ICE-driven cars that use an electric drive train to improve mileage or for performance enhancement.
• An HEV uses the electric propulsion system when the power demand is low.
• It is a great advantage in low-speed conditions like urban areas.
• It also reduces fuel consumption as the engine stays totally off during idling periods, for example, traffic jams.
• This feature also reduces the emission of greenhouse gases.
• When higher speed is needed, the HEV switches to the ICE. The two drive trains can also work together to improve the performance.
• It also enhances performance by filling the gaps between gear shifts and providing speed boosts when required.
• The ICE can charge up the batteries. The HEVS can also retrieve energy using regenerative braking.
• To attain these features. HEV configurations are being widely adopted by car manufacturers.

Energy flow while starting

• Fig. shows the energy flows in a basic HEV while starting the vehicle.

Fig. a) Direction of power flow during starting and stop

• The ICE may run the motor as a generator to produce some power and store it in the battery in this mode.

Fig. b) Direction of power flow during passing, breaking, cruising

Energy flow while passing:

• Passing needs a boost in speed, therefore the ICE and the motor both drive the power train.
• shows the energy flow taking place in the passing, braking, and cruising modes.
• During braking, the power train runs the motor as a generator to charge the battery by regenerative braking.
• While cruising. ICE runs both the vehicle and the motor as a generator, which charges the battery.
• The power flow is stopped once the vehicle stops.

Energy Management System (EMS):

Fig. Example of energy management strategy used in HEV

• Fig. shows an example of an energy management system (EMS) used in HEVs.
• Here it splits the power between the ICE and the electric motor (EM) by taking into account the vehicle speed, driver’s input state of charge (SOC) of battery, and the motor speed to attain maximum fuel efficiency.
• The controller splits power between the ICE and the motor by considering different input parameters.

3. Plug-In Hybrid Electric Vehicle (PHEV):

Concept:

• The PHEV concept arose to extend the all-electric range of HEVs.
• It uses both an ICE and an electrical power train, like an HEV, but the difference between them is that the PHEV uses electric propulsion as the main driving force.
• Therefore these vehicles need a bigger battery capacity than HEVs.
• PHEVs start in all-electric mode and runs on electricity.
• It switches to the ICE only when the batteries are low in charge to provide a boost or to charge up the battery pack.
• That means the ICE is used fire to extend the range. PHEVS can charge their batteries directly from the grid (which HEVS cannot) and they have the facility to utilize regenerative braking as well.
• Due to their ability to run solely on electricity for most of the time, their carbon footprint is much smaller than the HEVs.
• They consume less fuel as well and thus reduce the associated cost.
• The examples of PHEV are Chevrolet Volt and Toyota Prius

4. Fuel Cell Electric Vehicle (FCEV):

Concept:

• FCEVs also goes by the name Fuel Cell Vehicle (FCV). They got the name because the heart of such vehicles is fuel cells that use chemical reactions to produce electricity.
• Hydrogen is used as fuel for FCVS to carry out the chemical reaction. Hence they are also called hydrogen fuel cell vehicles.
• FCVs carry hydrogen in special high-pressure tanks.
• The other ingredient for the power generating process is oxygen, which it acquires from the air sucked in from the environment.
• The fuel cells generate electricity which goes to an electric motor that drives the wheels.
• Excess electrical energy is stored in storage systems like batteries or supercapacitors.
• Commercially available FCVs use batteries for this purpose.
• FCVS only produce water as a byproduct of its power generating process which is ejected out of the car through the tailpipe

Configuration:

Fig. FCEV configuration

• The configuration of an FCV is shown in Fig.
• Oxygen from air and hydrogen from the cylinders react in fuel cells to produce electricity that runs the motor.
• Only water is produced as a by-product which is released into the environment.

Advantages:

1. They produce their own electricity:

• An advantage of such vehicles is they can produce their own electricity which emits no carbon.

2. They reduce the carbon footprint:

• As these vehicles emit no carbon, it reduces their carbon footprint further than any other EV

3. Refilling is very fast:

• The most important advantage of these EVs is that refilling these vehicles takes the same amount of time required to fill a conventional vehicle at a petrol pump.
• This makes the adoption of these vehicles more likely shortly.

Disadvantages:

1. A major current obstacle is the scarcity of hydrogen fuel stations,
2. The high cost of fuel cells is very high typically more than $200 per kW, as compared to less than $50 per kW for ICE).
3. There are also concerns regarding safety in case of flammable hydrogen leaking out of the tanks.
4. High fuel cost.