How Do Electric Car Batteries Work? | The Science Behind Electric Car Batteries

The environmental benefits and ease of maintenance are among the top reasons an increasing number of car owners are ditching their gas-burning vehicles to invest in electric ones. This shift to electric mobility is not only great for the planet but also helps drivers save money in the long run.

However, despite their growing popularity, there is still a general lack of awareness about electric cars and how they operate. In fact, “how do electric car batteries work” is typically the top question among prospective buyers.

If you plan to buy a sleek electric car for yourself or a family member, this guide to electric vehicle battery technology may come in handy.

How Do Electric Car Batteries Work
Photo of a charging electric car

What Is An Electric Car Battery?

The battery of an electric car works as an energy accumulating system. It stores electricity and then transmits it to an alternating or continuous current engine.

The battery is also what makes these vehicles different from their gas-burning alternatives.

Instead of depending on fossil fuels and emitting planet-warming greenhouse gases, the modern electric vehicle battery technology uses electricity to power the motors, making them a sustainable and climate-friendly option.

Though all-electric vehicles (AEV) batteries may differ slightly from those of hybrid-electric vehicles (PHEV), their function remains the same.

The most common types of electric car batteries include lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries. In addition, the latest models have an average lifespan of eight years or 100,000 miles.

Interestingly, electric car batteries are also at the center of consumers’ concerns about investing in this climate-friendly technology.

Most buyers are concerned about how long these batteries may need to be charged and what distance the car may travel before running out of power.

If you also share similar concerns, please note that electric car batteries have come a long way in the last decade.

The latest electric car batteries boast a better range than the earlier models, which means you don’t have to worry about being stranded on the side of the road at an ungodly hour at night.

Similarly, the incredible improvement in charging times has also improved the efficiency and performance of these rechargeable batteries, providing drivers and passengers with an excellent experience.

Types of electric car batteries
Electric car battery

Check How to Wash an Electric Car

How Do Electric Car Batteries Work?

Electric car batteries may use the same chemistry as their traditional counterparts, but they have a drastically different internal design and functionality.

To put it simply, a regular internal combustion battery needs a short burst of high energy to crank the engine and start the car, after which the alternator takes over as the main power supply.

On the other hand, an electric vehicle battery is designed to constantly discharge energy to power the car.

Unlike traditional cars equipped with an internal combustion engine, AEVs feature an electric traction motor. These vehicles use a traction battery pack to store the current required by the motor to power the wheels.

This battery pack, which usually comprises a lithium-ion battery, has to be plugged into a wall outlet or electric vehicle supply equipment (EVSE) to be charged once the energy depletes.

PHEVs also have an electric traction motor that draws energy from a traction battery pack. However, these vehicles have a combustion engine as well.

Though they mostly run on electricity, they have the capability to switch over to fuel once they run out of power. The battery can be recharged either by plugging in or through the internal combustion engine.

Since PHEVs benefit from both technologies, they have a longer range than most AEVs, but they are not as eco-friendly.

Read How Long Does It Take To Charge An Electric Car

Types of Electric Car Batteries

Now that we know how electric vehicle battery technology powers the car, let’s look at some of the most common kinds of electric car batteries. 

1. Lithium-Ion Batteries

Today, most new electric cars use a lithium-ion battery, making it one of the most popular options among automakers and consumers alike.

In theory, these batteries are similar to the ones used in most portable electronic devices, including, but not limited to, laptops and cellphones.

However, in practice, lithium-ion electric car batteries have the capacity to hold a larger amount of energy, thus boasting a high power-to-weight ratio. They can last up to 12 or more years in moderate climates and from eight to ten years in harsh climates.

They are also more energy-efficient than most other types of AEV batteries and display a high-temperature performance.

Moreover, lithium-ion batteries are generally bigger than those found in gas-powered cars and are usually found underneath the interior carriage.

They consist of thousands of individual lithium-ion cells, which work together to ensure your car can travel great distances without demanding to be charged.

The low self-discharge rate is also one of the biggest advantages of lithium-ion batteries, ensuring they doesn’t run out of power even when you don’t drive your car for a few days.

Another great thing about these batteries is that they are largely recyclable, making them a perfect choice for those conscious of the environment.

How do electric car battery work
electric car battery

On the flip side, the biggest drawback of these batteries is their potential to ignite and explode if not treated with care. Therefore, electric car owners must be extremely careful while dismantling or removing lithium-ion batteries.


  • High efficiency
  • Ability to hold a charge for long
  • Better range
  • Recyclable
  • Longer lifespan


  • Large and heavy
  • It can potentially catch fire if not removed properly

Bottom Line

The benefits of lithium-ion batteries easily outweigh their drawbacks, making them the most prevalent choice for electric cars worldwide.

Read Can You Recycle Electric Car Batteries?

2. Nickel-Metal Hydride Batteries

While most of the latest electric cars feature lithium-ion batteries, you can find nickel-metal hydride batteries in older models of AEVs and PHEVs alike.

Moreover, some automakers are still using these batteries in their newer models because of their ability to withstand harsh weather conditions and longer life cycles. They are also highly tolerant of abuse.

Owing to these features, nickel-metal hydride batteries are considered an excellent option for those living in areas with blazing hot summers or freezing cold winters.

Additionally, the high amount of nickel in these rechargeable car batteries makes them easier (and more profitable) to recycle.

However, there are also quite a few drawbacks of using nickel-metal hydride batteries. Firstly, they have an approximately 40% lower energy density than lithium-ion batteries.

As a result, they are generally bigger than the alternatives. While their size helps circumvent the energy storage problem, it also significantly adds to their weight.

Secondly, they charge slower than lithium-ion batteries. The long and frequent charging cycles mean these batteries tend to run hotter, thus requiring a separate cooling system.

Lastly, these types of electric car batteries hydride batteries have a high self-discharge rate, which means they cannot hold power for long periods.

Nonetheless, most of these problems arise when these energy accumulators are used in AEVS. Since PHEVs can charge the battery through their combustion engine, nickel-metal hydride batteries usually perform better in hybrid cars.


  • Longer life-cycle
  • Recyclable
  • Can withstand harsh weathers
  • Tolerant of abuse


  • Relatively expensive
  • Heavier and larger
  • High self-discharge rate
  • Slow charging time

Bottom Line

Unless you live in a state with extreme weather conditions or own a hybrid car, nickel-metal hydride batteries may not be an ideal option for you.

Read How Much to Install Electric Car Charger in Garage

3. Lead-Acid Batteries

These types of electric car batteries are often used as secondary storage to supplement other battery loads.

As far as their chemical composition is concerned, the lead-acid batteries used in AEVs are not much different from those used in gas-fueled combustion engines.

Nonetheless, they have a different design that allows these batteries to power electric traction motors.

Interestingly, you are more likely to find lead-acid batteries in commercial vehicles. They are relatively inexpensive and can store more energy than other types of electric car batteries, which adds to their popularity.

Furthermore, these batteries are not likely to catch fire upon dismantling. They are also very reliable.

However, on the other end of the spectrum, lead-acid batteries perform rather poorly in cold temperatures and have a shorter lifespan than lithium-ion batteries.

While advanced lead-acid batteries are currently being developed, the ones available today are only considered suitable for ancillary loads.


  • Relatively less costly
  • High-powered
  • Safe and reliable


  • Short calendar life
  • Poor cold-temperature performance

Bottom Line

Lead-acid batteries may not be heavy on the pocket, but they only last for a couple of years. Moreover, they don’t perform well in cold regions.

So, if you live in an area with cold winters and want to invest in electric car batteries that will last for nearly a decade, these batteries may not be a good option for you.

Electric vehicle battery technology
Electric vehicle battery technology

Read How to travel in electric cars

The Science Behind Battery Capacity: Explained

The question “how do electric car batteries work” is often followed by a query about their capacity in kilowatts and kilowatt-hours.

If you are confused between the two, here is a quick explanation: Kilowatts, which is denoted by kW, is a unit of power that signifies how much energy a device requires to work.

Meanwhile, a kilowatt-hour, or kWh, is a unit of energy that shows how much energy has been used.

For example, a 100-watt bulb uses 0.1 kilowatts per hour. However, when it comes to electric cars, they typically use around 2,000 kWh a year.

Since electric cars weigh approximately two tons or more, the electric traction motor requires more energy to move the car on the road. This means the battery must store sufficient energy for the vehicle to travel from Point A to Point B without shutting off in the middle of the journey.

It is the main reason electric car batteries are significantly larger than those used in gas-powered vehicles.

Additionally, the latest electric vehicle battery technology does not rely on a single battery like most portable electronic appliances. Instead, it uses a battery pack.

The energy capacity of AEV batteries is measured in kWh. A Tesla Model S can deliver as much as 100 kW of energy for one hour, which is significantly less than what most cars will spend while their owners drive to school or work.

Therefore, the battery will last for multiple hours before it requires to be plugged in.

Furthermore, if you are planning to buy an electric car, please make sure to select one with a battery capacity big enough to accommodate your day-to-day travel requirements.

If most of your driving includes short trips to different parts of the town, investing in an AEV with a smaller battery capacity will be an ideal option for you.

It is also worth mentioning that most manufacturers incorporate additional spare capacity in electric car batteries to prolong their average lifespan.

As the battery begins to degrade and loses its capacity to store energy, this additional capacity comes in handy.

It ensures the range of the vehicle remains the same as long as the battery capacity remains above 80%.

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To conclude, all-electric vehicles or AEVs come with an electric traction motor instead of a combustion engine. This motor draws power from an energy source called the battery to propel the car forward by moving the wheels.

Since these cars do not require petrol or gas and run solely on electricity, they don’t emit any hazardous gases through the tailpipe, making them a sustainable and eco-friendly option.

There are three main types of electric car batteries: lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries.

While rechargeable lithium-ion batteries are more prevalent, nickel-metal hydride batteries are usually found in older hybrid vehicles, whereas lead-acid batteries are mostly used as a secondary power source in commercial vehicles. Moreover, their capacity is measured in kilowatt-hour.

We hope our comprehensive guide has answered your most pressing questions about “how do electric car batteries work?”

Read Do All Electric Cars Stop Charging Once the Battery is Fully Charged?

Frequently Asked Questions

These are the most frequently asked questions about electric car batteries and how they work.

How long do batteries last in electric cars?

Most electric car batteries last between 10 and 12 years before they have to be replaced. Some may even last longer.

Do electric car batteries run out of power?

Electric car batteries discharge may energy when the vehicle is in motion and gradually run out of power. Therefore, you are required to charge the battery pack once the energy begins to deplete.

Do electric cars lose charge when parked?

Unfortunately, electric cars do lose charge when parked. However, if you have a lithium-ion battery, this discharge is going to be minimal.