Internal combustion engine cars get their energy from burning gasoline or diesel, while electric cars get their energy directly from a large set of batteries.
They're much like larger versions of the lithium-ion (Li-ion) batteries in mobile phones - instead of using a single cell like a phone, electric cars use a battery pack made up of thousands of individual lithium cells. Ion cells work together. When a car is charged, electricity is used to create chemical changes inside the battery. When it's on the road, these changes reverse to generate electricity.
Electric vehicle battery technology
Electric car batteries go through "discharge" cycles that occur while driving and "charge" cycles that occur when the car is plugged in. Repeating this process over time affects how much power the battery can hold. This reduces the mileage and time required to recharge between each journey. Most manufacturers' batteries come with a warranty of five to eight years. However, current predictions are that electric vehicle batteries will last 10 to 20 years before needing replacement.
The way batteries and car electric motors work together is surprisingly simple-the battery is connected to one or more electric motors that drive the wheels. When you press the accelerator, the car immediately sends power to the electric motor, which gradually consumes the energy stored in the battery.
The electric motor also acts as a generator, so when you take your foot off the accelerator, the car begins to slow down and convert its forward motion back into electricity - this is even more intense if you hit the brakes. This regenerative braking recovers energy that would otherwise be lost and stores it again in the battery, improving the car's range.
Electric car battery lithium ion
Lithium-ion (Li-ion) batteries are a type of rechargeable battery used in electric vehicles and many portable electronics. They have higher energy density than typical lead-acid or nickel-cadmium rechargeable batteries. This means battery manufacturers can save space and reduce the overall size of the battery pack.
Lithium is also the lightest of all metals. However, lithium-ion (Li-ion) batteries do not contain lithium metal, but ions. For those of you wondering what an ion is, an ion is an atom or molecule that carries an electric charge resulting from the loss or gain of one or more electrons.
Lithium-ion batteries are also safer than many alternatives, and battery manufacturers must ensure safety measures are in place to protect consumers in the event of battery failure. For example, manufacturers equip electric vehicles with charge protection devices to protect the battery when fast charging is repeated over a short period of time.
Characteristics of lithium-ion batteries
Lithium-ion batteries are also used in consumer electronics (phones, laptops) and electric vehicles. The main reason for this large-scale success is the storage density allowed by lithium-ion technology.
The concept of density refers to the ratio between the storage capacity provided by a battery and its volume or weight. By comparison, lithium-ion batteries have a density of about 300 to 500 Wh/kg, or about ten times that of lead-acid batteries.
While we await the potential development of innovative technologies such as solid-state batteries, today's lithium-ion technology represents the best compromise between capacity, volume and mass in the electric vehicle space. It features high voltage, easy charging and durability, making it suitable for use scenarios that complement each other throughout the life cycle and is in line with the principles of circular economy.
