What Is an EV Battery Made Of?

An EV battery and its components can be a mystery. Here, we shed light on what EV batteries are made of, how they are produced, how they work, and what happens to them when they are done powering electric vehicles.

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Discover the essential components and types of EV batteries, from lithium-ion to the promising solid-state technology.
Learn how EV batteries propel vehicles and associated tehcnologies like regenerative braking systems.
Explore the lifecycle of EV batteries, from their cutting-edge construction to their sustainable recycling and repurposing, paving the way for a greener tomorrow.

Have you ever looked at an EV and wondered what an EV battery is made of or how it works?

You are not alone.

Here, we examine what goes into making an EV battery, the different types, how they work, and what happens when they are recycled or repurposed.

The different types of EV battery cells

When it comes to the structure of EV batteries, there are three basic types of cells: cylindrical cells, prismatic cells, and pouch cells.

Cylindrical cells: the most commonly used format. Cylindrical cells are self-contained in a cylindrical format.
Prismatic cells: much larger than cylindrical cells. Prismatic cells use less material for casing and can often store more energy and deliver higher power due to their size.
Pouch cells: often encased in a soft plastic casing, meaning they take up less space. However, their relatively fragile casing usually requires additional protection.

Electric car batteries are not a single unit but consist of hundreds of cells arranged in an array. This includes the cells mentioned previously, which are grouped into modules. These modules are then connected to form the final, full-sized battery pack (what most people commonly refer to when they say EV battery).

What materials are often used in EV batteries?

When talking about EV battery materials, we most often talk about the materials in and around the cells.

Nickel manganese cobalt (NMC) and nickel metal hydride (Ni-MH) were popular choices for EV battery cells early on but have since been replaced by other types.

Today, EV battery cells are often equated to lithium-ion. While this is the most common composite used today, there are others.

Briefly put, there are three types of batteries most commonly used in electric vehicles today:

Lithium-Ion: Widely used in electric vehicles like BEVs and PHEVs due to their high energy density and long lifespan. A key benefit is their low self-discharge rate, allowing them to retain charge longer when not in use, unless they experience vampire drain.
Nickel-Metal Hydride (NiMH): Hybrid vehicles often use nickel-metal hydride batteries rather than lithium-ion. They use a mix of nickel, metal hydride, and other materials to store energy. They have lower energy capacity than lithium-ion batteries but offer better energy density than lead-acid batteries.
Solid-State: While still mostly in development, solid-state batteries promise significant advancements for EVs. Using solid electrolytes means potentially higher energy density, faster charging, and improved safety.

What are the key components of an EV battery?

Apart from the materials used, key components play central roles in making an EV battery:

Electrodes: The battery’s power transfer points. The anode (negative) and cathode (positive) allow electrons to move during charging and discharging. They are often made from materials like porous carbon with a platinum catalyst.
Electrolyte: A conductive liquid made of the likes of lithium salt in an organic solvent. It enables ions to move between electrodes and is crucial for battery performance, safety, and lifespan.
Separator: A barrier made of materials like polyethene that keeps the electrodes apart to prevent short circuits while allowing ions to pass. Thickness and pore size affect battery power and energy capabilities.
Casing: The protective shell, typically made of steel or aluminium, shields the battery cells from damage.

How an EV battery works

An EV battery drives the vehicle’s engine and provides propulsion.

When you press the accelerator in an electric vehicle (EV), the battery discharges energy to power the motor. Lithium ions and electrons flow inside the battery from the anode to the cathode, creating an electric current. This current is sent to the motor, where it’s converted to momentum when the motor generates a rotating magnetic field that pulls the rotor, which in turn spins the gears and drives the vehicle’s wheels.

As the vehicle moves, the battery continues to supply energy, but the process changes when you release the accelerator. The motor, now acting as a generator, slows down the vehicle by converting the kinetic energy back into electrical energy, recharging the battery. This regenerative braking system allows the EV to recover some energy, improving efficiency and extending the driving range.

What happens at the end of an EV battery’s lifetime?

When EV batteries reach the end of their life, they can either be repurposed (for example, as energy storage units for renewable energy sources) or recycled.

The recycling process includes collection and disassembly.

During disassembly, materials are recovered through techniques like sieving and magnetic separation. The recovered materials are then refined to remove impurities and prepare them for reuse.

Remaining waste or byproducts are managed and disposed of in ways that prevent or minimise environmental harm.

What is the future of EV batteries?

EV battery technology continues to improve. For example, ranges are increasing. For example, Mercedes-Benz recently re-broke the 1,000km (621 miles) on a single charge record with its VISION EQXX.

New materials and construction methods, such as solid-state batteries, are also appearing, promising to improve EV battery performance, making them more efficient and, in turn, using fewer raw materials.

Beyond materials, EV battery recycling is also improving and the amount of materials recovered for use in future EV batteries is steadily increasing.