An electric vehicle revolution is well underway here in Ireland and is on the cusp of becoming mainstream. With rising tides and the dramatic effects of climate change coercing many of us to question our motoring habits. The motor industry is on the road to making solely electrified vehicles by the year 2050.
Hearing all of these new terms and not a hundred percent sure what all the fuss is about?
Good for the environment, great fuel economy, helpful for climate change, etc, etc... But what are the real benefits of switching to an electric vehicle and why are they becoming increasingly popular? You might also still be attached to the stigma of EV’s being highly expensive however the price has rapidly dropped over the years by 70% and the range is continuously increasing.
Electric vehicle (EV) classifies three different types of vehicles – a battery-operated electric vehicle (BEV), a Hybrid Electric Vehicle (HEV), and a plug-in electric vehicle (PHEV). The bev, hev and fev as we like to call them. Each features batteries and electric motors that work independently to move the vehicle with the use of electricity.
Ok, so here are the basics to get you up to speed:
EV’s are like automatic cars - they have a forward and reverse mode. When you place the vehicle in gear and press on the accelerator pedal these things happen:
Power is converted from the DC battery to AC for the electric motor
The accelerator pedal sends a signal to the controller which adjusts the vehicle's speed by changing the frequency of the AC power from the inverter to the motor
The motor connects and turns the wheels through a cog
When the brakes are pressed or the car is decelerating, the motor becomes an alternator and produces power, which is sent back to the battery
EV Technical Terminology
AC/DC and electric cars
AC stands for Alternating Current. In AC, the current changes direction at a determined frequency, like the pendulum on a clock.
DC stands for Direct Current. In DC, the current flows in one direction only, from positive to negative.
Battery Electric Vehicles
The key components of a Battery Electric Vehicle are:
Inverter
An inverter is a device that converts DC power to the AC power used in an electric vehicle motor. The inverter can change the speed at which the motor rotates by adjusting the frequency of the alternating current. It can also increase or decrease the power or torque of the motor by adjusting the amplitude of the signal.
Battery
An electric vehicle uses a battery to store electrical energy that is ready to use. A battery pack is made up of a number of cells that are grouped into modules. Once the battery has sufficient energy stored, the vehicle is ready to use. Battery technology has improved hugely in recent years. Current EV batteries are lithium-based. These have a very low rate of discharge. This means an EV should not lose charge if it isn't driven for a few days or even weeks.
Battery charger
The battery charger converts the AC power available on our electricity network to DC power stored in a battery. It controls the voltage level of the battery cells by adjusting the rate of charge. It will also monitor the cell temperatures and control the charge to help keep the battery healthy.
Controller
The controller is like the brain of a vehicle, managing all of its parameters. It controls the rate of charge using information from the battery. It also translates pressure on the accelerator pedal to adjust the speed in the motor inverter.
Charging cable
A charging cable for standard charging is supplied with and stored in the vehicle. It's used for charging at home or at standard public charge points. A fast charge point will have its own cable.
Another great aspect of the EV is that it is incredibly quiet but holds fast acceleration. EV’s also features regenerative braking meaning the electrics can slow your car down, and recharge your battery without using the brakes!
Hybrids (HEV)
These are known as HEV’s. These vehicles have both an internal combustion engine and an electric motor. The electric battery, however, is only charged by the ICE, the motion of the wheels or a combination of both. There is no charging connector.
Plug-in hybrid (PHEV)
These are similar to the HEV, in that they use an internal combustion engine (ICE) and electric motor. You can charge PHEVs from an electricity source, and access cheaper and cleaner electric power. The battery's energy is recharged by the ICE, wheel motion, or by plugging into a charge point.
Range vs Capacity
The total energy or capacity of an EV battery pack is measured in kWh (kilowatt-hours). The vehicle's range is how far a vehicle can travel on a full charge, this is typically in proportion to the capacity of the battery. Every model has a different battery size and efficiency, and therefore a different range.
As is the case for ICE vehicles, with fuel tanks of different sizes and mpg, EVs vary widely on the distance they can travel on a fully charged battery. Other variables that have an impact on real-world electric range of a BEV or PHEV include driver behaviour (specifically speed, as with ICE vehicles the faster you go the less the range), driving conditions, topography, passenger load, auxiliary use, and climate.
Electric car batteries are being built to have a long lifespan, with most manufacturers like Hyundai guaranteeing 8 years or 160,000km (SoH of batteries >70-80%).
Some Consumer Reports in the US estimate the average EV battery pack's lifespan to be at around 320,000 Kms, which is nearly 19.5 years of use if driven at the Irish average per car 16,400 Km per year (CSO 2019), longer than the expected lifespan of most vehicles (which is 10-14 years)! (Source SEAI)
