How Do Batteries in Electric Cars Work?

Cars are something that we use on a daily basis. The only problem is the lasting negative effect they leave on this planet. While we pollute the air and exhaust our planet’s natural resources getting from point A to B, others attempt to create alternatives that are less harmful to the planet.

Electric cars first appeared in the mid-19th century. Anyos Jedlik, a Hungarian inventor developed the first prototype of the electric motor. Following its inception, a series of other inventors also toyed with the idea and further developed the idea. In 1834, Thomas Davenport a Vermont blacksmith built a similar contraption, its main difference was that it ran on an electrified track.

As time passed many attempted to improve the idea but it eventually saw a decline in interest and for some time remained on the backburner. Things have however changed in the recent past and massive strides have been made in cars powered by alternatives to fuel or gas. With the state the world is in from over-population, fossil fuels, and greenhouse gasses, something needed to be done.

The below chart shows the growth in electric vehicles globally, categorized by countries and continents, with China, European nations, and the United States leading the way.

Top selling light duty plug in electrical vehicles globally chart

Now, in order to understand how a battery in an electric car works, we need to know more about electric cars in general.

What is an electric car?

Cars these days can run on anything. Alternatives such as water, cooking oil and in this case, electricity, have all been tested. Things are changing.

These alternatives work by turning potential energy into kinetic energy. In conventional cars, the potential energy is locked inside gas pumped into your tank. It is then released due to ignition by the spark plug and the function of the engine itself. A chemical reaction takes place inside the engine.

Thus the hydrocarbon molecules in gasoline burn with oxygen and release heat pushing the pistons that turn the wheels. Without the right combination of fuel, air and the spark, it would not work effectively. As all of this takes place internally it is called internal combustion.

Electric cars also store a chemical energy which is released electrochemically and involves no form of combustion. Electrons ping from their slowly discharging batteries. This means there is no burning of any fuel and thus creating no air pollution.

In the below schematic we see the inside of an electric car, with the major components highlighted in green, showing how they all come together to create a smooth eco-friendly ride.

Electric car inside schematic

How do electric car batteries work?

The energy storage system that is in an electric car comes from a battery. The type of battery depends on the vehicle. Some are all-electric (AEV) while others are plug-in hybrid electric (PHEV). AEVs use traction battery packs which is usually a lithium-ion battery. The traction battery pack is meant to be plugged in and recharged.

Like AEV the plug-in hybrid electric vehicles also feature an electric traction battery pack to power the electric traction motor. The main difference is that this battery also has a combustion engine.

Then PHEVs run on electric power. Once the battery has been depleted the vehicle switches to fuel in order to power itself. This powers an internal combustion engine. The battery can be recharged by plugging it in, through regenerative braking. This combination of both fuel and battery means the PHEVs have a longer range than the all-electric counterparts.

We currently have battery technology which is meant for an extended life which is typically 8 years or 100,000 miles. There are batteries out there that are capable of lasting 12 to 15 years in moderate climates or 8 to 12 in extreme climates.

AEVs and PHEVs are usually charged through standard connectors which are compatible with any LEVEL 1 (120V AC) LEVEL 2 (240V – Residential/208V – Commercial) type outlets. There are charging stations which use receptacles which are not standardized such as SAE and CHAdeMO for example. Note the type of vehicle will determine the charging station you can use.

Electric car schematic

What are the different types of electric batteries?

There are four types of batteries found in electric cars:

#1 Lithium-ion batteries

Easily the most common battery to be used in electric cars is the lithium-ion battery. These batteries are also used in day to day devices such as computers and cell phones. The lithium-ion batteries are highly energy efficient, have good high-temperature performance and also have a high power-to-weight ratio. What this all means is that the battery can hold a large amount of energy for their weight.

This is a vital factor for use in an electric car. The car can travel further on a single charge with less weight. Due to their low self-discharge rate, lithium-ion batteries are better than other batteries with the ability to maintain and hold a full charge over time.

Electric car parked charging

You will find Lithium-ion batteries in both AEVs and PHEVs. The chemistry varies from those found in our everyday devices. The majority of lithium-ion batteries are recyclable meaning this is an environmentally friendly choice.

#2 Nickel-metal hydride batteries

More often used in hybrid-electric vehicles, nickel-metal hydride batteries are also found in some all-electric cars as well. Hybrid-electric vehicles rely on fuel to recharge the battery unlike the other method of using an external plug-in source. This is what excludes them from having a definition of being a pure electric car.

Nickel-metal hydride batteries are known to have a longer life expectancy than lithium-ion or lead-acid batteries. The main issue found with nickel-metal hydride batteries is that they’re very expensive and have a high self-discharge rate. They also generate significant heat at high temperatures so while they are safe and tolerant to abuse, they have problems too.

These issues amount to the batteries being less effective for rechargeable electric vehicles. Nickel-metal hydride batteries for all the reasons listed before mean they’re used primarily in hybrid electric vehicles.

#3 Lead-acid batteries

Lead-acid batteries are mainly used in electric vehicles in order to supplement other battery loads. They’re inexpensive, safe, high-powered and reliable. Unfortunately, they’re not without flaws. They have a very short lifespan and during cold-temperatures, they under perform significantly.

This makes them a difficult choice to use in electric vehicles. While they are making further developments in high-power lead-acid batteries they will continue to be used in commercial vehicles as nothing more than a secondary storage.

#4 Ultracapacitors

Ultracapacitors function in a different way to traditional batteries. Ultracapacitors store polarized liquid between an electrode and an electrolyte. Steadily the liquid’s surface will start to increase and then the capacity for energy storage begins to increase. These batteries are similar to lead-acid batteries in the sense that they’re most useful as secondary storage devices. This is because ultracapacitors help electrochemical batteries level their load. They also have the ability to provide some extra power when electric vehicles are accelerating and during regenerative braking.

We can now compare these different battery types in the below graph, which displays their energy density versus their power density. Battery energy density versus power density

Charging a Hybrid

Having a hybrid car is like having two cars in one. Since you have both a conventional engine which uses gasoline (petrol) for optimized freeway driving as well as an electric motor for more environmentally friendly and economic traveling. Depending on designs the wheels are driven by either the engine, the motor or both.

Charging Electric Cars

One of the main selling points of an all-electric car is the go green label that goes with it. You’re taking a firm step forward in helping the environment. Unfortunately, it’s not enough having an electric car it’s also about how you charge it. If you are using electricity from your home you’re not doing it right. You would need to begin investing in solar power in order to truly grasp the method of cutting down your greenhouse gas emissions. Statistics show that 80% of charging an electric car battery happens at home. So you need to consider the option of solar power.

Solar panels can be pricey but you need to think about it in the long-term sense. Car owners spend on average $200 a month on petrol. That’s a lot of money. You get an electric car and use city power, who knows what your bills going to look like. Solar panels are a once-off expense with some minor monthly maintenance. Thereafter you have free charging for your vehicle forever.

Electric cars charging under solar roof

Hybrid Cars

Electric or gasoline cars have their advantages and disadvantages. You’ll find that a vast majority of electric cars on the road are hybrids. As stated before hybrid means they have two engines and two sources of power. There are a few different type of hybrids;

Parallel hybrids – The wheels are powered by both the engine and motor.

Series hybrids – The wheels are powered by the motors only and the engine drives the motor like a generator. It recharges the battery.

Full hybrids – The electric motors and batteries are powerful enough to drive the engine.

Mild hybrids – The small motors mean they are unable to power the car alone. They instead assist the engine which means the car is able to switch off when the car idles in traffic.

Ordinary hybrids – The batteries in ordinary hybrids are charged by the engine as well as energy which has been recovered from the regenerative brakes.

Plugin Hybrids – They are able to be refueled at charging stations or domestic power supplies. Plugin hybrids are also capable of being driven by the motor and batteries alone and they are more like conventional electric cars.

Electric car charging at street charging station

Electric Cars

While electric cars and gas-powered cars have many things in common their main differences are:

  • The stored energy that they each use (gasoline vs electricity).
  • The machine which is used to convert it into kinetic energy (engine vs electric motor).
  • The way the stored energy powers that machine (gearbox and transmission – ordinary vehicles and directly – electric vehicles).

We’re going to take a quick look at the components of electric cars such as the batteries and the motor.

Electric Motor – An engine spins around at high speeds in order to work as efficiently as possible. A car’s wheels don’t need to go as fast as this motor makes possible. If you were moving off from a cold start or a traffic signal you’d need the engine to produce a great deal of force at a low speed. Immense force, in this case, is known as torque.

The pros and cons of electric cars

The good…

#1 Emissions

It is great to know that your car truly is a firm step in the right direction to creating a greener earth. Unfortunately, it’s not 100% zero emission. The vehicle does produce CO2 when it’s being recharged. This doesn’t devalue the point of going green but if your electricity is provided by a wind turbine or solar panels you would be happy to know you have cut out that small amount of CO2 emission.

#2 Efficiency

It is a proven fact that electric cars are more efficient than traditional cars. This is because electric engines are 80% more efficient than traditional internal combustion engines. It is known that some cars burn petrol faster meaning you are wasting petrol when it is combusting. Hybrids are praised in this regard due to the fact that they switch engines when the opportunity arises.

#3 Performance

Electric cars are known to produce high torque even at low speeds. This means that they are able to accelerate faster than that of gasoline cars. They don’t reach their peak torque until they have reached high engine speeds. They also happen to be a lot quieter and smoother.

#4 Maintenance

The great thing about electric cars is their lack of bits and pieces. Traditional cars are a maze of pipes and moving parts. If they are using no transmission and no gearbox this means that there is more space and less maintenance.

The bad…

#1 Batteries

It is something that no one fully understands yet and can still be called the Achilles heel of electric cars. While gasoline isn’t a something to praise it does yield results. A tank of gas carries a lot more energy than a bunch of batteries. It’s also unfortunate that it takes batteries longer to recharge. Gas, on the other hand, can be filled up anytime and takes seconds.

#2 Convenience

This goes back to charging. It’s more convenient to own a gas car due to the fact that you can get petrol very easily and it takes a small amount of time to do so.

#3 Status quo

While an electric car is cheaper in some sense, the initial purchase price is rather high. People struggle to take the chance on an electric car due to the concerns they have such as charging. Some countries are attempting to make it more affordable to own an electric car by having tax breaks on electric models.

What does the future of the electric car industry hold?

We are living in exciting time. People will continue to improve upon the electric car model. As further knowledge is gained regarding batteries and charging we will see a decline in the cost of the cars.

The world will need to evolve into a greener way of thinking. If we continue to deplete our planets natural resources we will soon find ourselves with little alternatives. Electric cars are the future but for now, they remain a work in progress.

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