Electric vehicle battery – the power source for propulsion is the main component of an electric vehicle. Rechargeable batteries (secondary batteries) are the source of energy for an electric vehicle.
Different battery technologies are used in an electric vehicle. The selection of the batteries is based on their advantages, applications, and cost. The distance that can travel by an electric vehicle depends mainly on battery capacity.
The size and cost of a vehicle increase when we add more batteries to the vehicle. It’s a fact that if the battery is not up to the mark, the performance of an electric vehicle would be poor. Please read My Experience with Electric Scooter!
The cost of electric vehicle batteries decrements in since last few years and it will further decrease. Automotive industries focus on low cost, high efficiency, high capacity battery development.
Tesla motors established a Gigafactory for battery manufacturing.
Let’s check some desired characteristics of electric vehicle battery technologies.
Desired characteristics of Electric Vehicle Battery
Electric vehicle batteries are expected to have the following characteristics.
#1 Deep cycle battery
A deep cycle battery can discharge almost up to the maximum of its capacity. They can be discharged up to 20% of maximum capacity but usually, it caps maximum discharge value to 45% for a longer life span. An electric vehicle battery is expected to be a deep cycle battery so that we can get maximum out of it.
#2 High Ampere hour capacity
Distance traveled by the vehicle in a single charge depends on the capacity of the battery. A high ampere-hour battery could help out the vehicle to travel for a longer distance which a driver expects from his EV.
The higher rating battery has some negative impacts on the vehicle. The higher capacity battery increases the size and cost of the vehicle. As a result, it leads to install a high rating motor to drive the vehicle.
#3 High power to weight ratio
An electric vehicle motor should be capable of supplying high power to the motor whenever it is necessary and it should not demand a bigger battery. It is desired to have a high power to weight ratio battery in an electric vehicle.
#4 High energy to weight ratio
Weight of battery does matter in an electric vehicles and it should be as light as possible, mainly for improved range, and life.
You shall read: Life expectancy of electric vehicle: How long an EV lasts?
#5 Low cost
The lower initial cost is one of the recommended characteristics of an electric vehicle. Currently, an electric car is 30 to 50% costlier than similar ICE car. The future of electric vehicles would be definitely affected by the cost of the vehicle.
Common Electric Vehicle Batteries
Commonly used electric vehicle batteries are Lead-acid, Nickel-metal hydride, Lithium-ion, Zebra, etc. Short information about these electric vehicle battery tehnoloies are given below.
Traditionally electric vehicle has used Lead-acid battery due to their matured technology and low cost. But the deep-cycle lead-acid battery has shorter life than other battery technologies.
The life span of a lead-acid battery is around 2 to 3 years. The lead-acid battery is now limited to a few electric vehicle battery applications due to the drawbacks.
Nickel metal hydride battery
Nickel metal hydride batteries are long-life batteries compared to a lead-acid battery. They are considered as a matured battery technology now.
Energy density is more in Nickel-metal hydride batteries. Even though the charging and discharging efficiency is lower than that of lead-acid batteries, Nickel-metal hydride batteries position at the top with their long life and energy density, in the list of electric and hybrid electric vehicles.
Lithium-ion batteries are the most common batteries used in recent electric vehicles. High energy density, power density, and charging efficiency are the advantages of Lithium-ion batteries.
The energy density of 200 Wh/kg and more than 85% of charge/discharge efficiency makes Lithium-ion battery suitable for an electric vehicle.
The weight of the vehicle significantly reduces due to the above-mentioned advantages of the battery. But the life of a lithium-ion battery is not that impressive. It lasts for a few 1000 charging cycles.
Ultra-capacitors are not a battery technology, it is another method to store electrical energy for electric vehicles. Ultra-capacitors have very high power density and low energy density.
A combination of battery and ultra-capacitor can be used in electric vehicles to overcome a few drawbacks and to extend the life of the battery. Momentarily available electric energy from regenerative braking can be stored in ultra-capacitors and eventually use to charge a battery.
But the Li-Ion batteries that have the capacity to charge fast makes the ultracapacitors not a necessity in electric vehicle regenerative braking applications.
The electric vehicle battery is an important component in an electric car that affects the size, cost, and range of the vehicle. There are different battery technologies used in an electric vehicle and we have discussed them in this post.
The price of an electric vehicle depends on the price of the battery used in the vehicle. It contributes the lion’s share to the initial cost of the vehicle
It is a good sign that there are a lot of researches happening in battery technology and the cost of the batteries shows a reduction in every year.