When people refer to electric vehicles (EVs), they’re usually talking about fully electric cars powered by a battery, commonly known as Battery Electric Vehicles (BEVs). However, other types of vehicles can also be categorized as EVs, including:
⦁ Hybrid Vehicles
⦁ Plug-in Hybrid Vehicles
⦁ Fuel Cell Electric Vehicles (FCEVs)
Among these, the most common types of EVs on the road today are hybrids and battery-powered vehicles.
How the Battery in an EV Works
All EVs, except those powered by a fuel cell, rely on a battery to store the energy needed to power the vehicle. Typically, these batteries are made of lithium-ion, similar to an industrial-strength version of the batteries found in your electronics.
EV batteries are usually constructed from stacks of cells organized into units and laid out in a large bank along the bottom of the vehicle, known as a traction battery. This assembly is charged with electricity from the grid via a charging station or by plugging the vehicle into a home power socket. Larger vehicles like trucks and SUVs powered by a battery will have correspondingly larger battery banks.
Once fully charged, the vehicle has a set range before needing to be charged again. Electric cars come with additional features to extend battery life, such as turning off the engine when the car isn’t in motion and using the kinetic energy generated during braking to recharge the battery.
Fuel cell vehicles operate somewhat differently. Instead of a battery, they use a tank of stored hydrogen gas, mixing this hydrogen with the oxygen in the air to create an electricity-forming chemical reaction. Once the gas is depleted, the tank needs to be refilled, which often takes less time than recharging an EV’s battery.
Advances in EV battery technology are continuously being made, which likely means that the range of EVs will continue to increase as new designs and innovations are introduced.
Electric Motor vs. Gas Engine: What’s the Difference?
Internal combustion engines powered by gas use compressed, ignited fuel to move pistons connected to a crankshaft, which turns the vehicle’s wheels. An all-electric vehicle (EV) uses the same principle of rotation to propel a vehicle forward but achieves this in a different way.
Instead of pistons, an EV uses electromagnets to get the crankshaft moving. The electric motor in an EV consists of a system of magnets, some of which are stationary and some of which rotate. The rotating magnets are driven by continuously switching the polarity of the magnets that need to spin.
Imagine those science experiments from school where you tried to push two magnets together, only to feel the resistance as like poles repelled each other. This basic principle of magnetic resistance is what rotates an EV’s motor and spins the vehicle’s wheels.
To create that resistance, the rotating magnets must always have an opposite charge to the stationary ones. This is achieved by a device called an inverter. The inverter draws power from the EV’s battery to switch the polarity of the rotating magnets around 60 times per second. This constant switching creates sustained magnetic resistance, powering the motor.
This design is more efficient than an internal combustion engine because the motor is built to spin from the start, while a gas-powered engine must use a crankshaft to convert the pistons’ up-and-down motion into rotary motion to turn the wheels. Additionally, adjusting the frequency of the inverter’s polarity switching gives the driver finer control over an EV’s speed and torque compared to what is possible with a gasoline engine.
Are EVs Really More Sustainable Than Gas Vehicles?
All-electric vehicles don’t burn fossil fuels, so they don’t emit any harmful exhaust from their tailpipes. In hydrogen fuel cell vehicles, the only byproduct is water, produced from mixing hydrogen and oxygen. In this sense, EVs are more sustainable and environmentally friendly than gas vehicles. However, the sustainability of EVs also depends on how their batteries are built and sourced.
The minerals needed to manufacture EV batteries will need to be mined on a larger scale if electric vehicles are to compete with gas-powered ones. There’s also the question of what to do with these batteries once they reach the end of their useful lifespan. The Union of Concerned Scientists has highlighted key measures to ensure the sustainability of EV batteries, including recycling programs, strong workplace health and labor standards, and the use of renewable energy in manufacturing.
Battery manufacturers are also exploring the use of more readily available materials in their designs. For example, some new battery technologies are incorporating aluminum to reduce the amount of cobalt required per battery.
Another consideration regarding the sustainability of EVs is the source of the electricity used to charge them. Power plants that produce electricity to fuel EVs may still generate greenhouse gas emissions, depending on the energy source. However, the emissions are generally lower than those produced by gas vehicles. Greater investment in renewable power sources, like wind and solar, could further reduce the environmental impact of generating electricity for EVs in the future.
Authored by Frank A. Forelli at EV Charging Solutions LLC