The craze for electric vehicles is at an all-time high due to the growing environmental concern and rising cost of fuels. With different government subsidies in place, people are shifting towards EVs, especially in the two-wheeler segment.
One of the most critical components of an EV is the battery pack. The battery pack is used to drive the motor and so the vehicle.
The cost of an EV battery is almost half of the vehicle cost. So we must know about the Types Of Batteries Used In EV Vehicles to make a wise decision.
What Does A Battery Mean To EV?
A battery is the heart of an EV. It drives the motors and other supplementary equipment. A battery pack usually contains several battery cells each carrying a specified voltage.
All batteries have a negative and a positive electrode. Electrons flow from the negative to the positive when the terminal is connected to electrical power. During this process, the battery stores the energy.
Similarly when the battery is discharging electrons flow from the positive electrode to the negative electrode. When there is no electron flow, the battery is considered dead.
Typically a battery lasts for a couple of hundred miles depending on the type of battery. Here I am talking about the traction battery and not the auxiliary battery. A traction battery is used for driving the motor whereas a auxiliary battery is used for powering supplementary devices in the vehicle.
Most of the time consumers replace the traction not because the battery is dead but because the battery is degraded beyond a certain limit that it can not hold enough charge to run the vehicle for certain miles.
Most manufacturers offer 8 years and 160000 km warranty on battery. That does not mean that after 8 years the battery will die. But you won’t get the same range as when the battery is new. Lithium-ion EV battery has a degradation rate of around 3-5% per year.
Types Of Batteries Used In EV Vehicles
There are mainly three types of Batteries Used In EV Vehicles. Although there are many sub-types the core technology remains the same.
- Lithium Ion Battery
- Nickel-Metal Hydride Battery
- Lead-Acid Battery
Lithium Ion Battery
Lithium Ion batteries are popular for high energy density. This means more energy can be stored in less space. A typical lithium-ion battery has an energy density of more than 140 Wh /kg.
Due to its high energy density, these batteries are ideal for EVs as they will consume less space. Lithium Ion batteries are 1/3 lighter than similar capacity other battery types available in the market.
These batteries are also good at high temperatures which is a plus as EVs will exposed to high temperatures most of the time.
In terms of self-discharge, these batteries are the best as these batteries will only discharge by 2-3 per day. If you are not sure what self-discharge means, it is the rate at which batteries discharge when not in use.
Due to the low discharge rate, it can hold a charge for a longer time. A typical lithium-ion battery should last for the life of the vehicle. If not, easily it can survive 8-10 years or 200K-300K miles considering you are following all the best practices of using the battery.
The Lithium-ion battery could be recycled with minimum wastage. But still, companies lack a proper plan to recover those used batteries.
The manufacturing cost of lithium-ion batteries is 40% higher than other battery cost. But due the high energy density and resistance to temperature make it an ideal choice for EVs.
Types Of Lithium Ion Batteries Used In Electric Vehicles
There are different types of Lithium Ion batteries used in EVs
- Lithium iron phosphate (LFP)
- Lithium Titanate Oxide (LTO)
- Lithium-Ion Cobalt Oxide (LCO)
- Lithium Nickel Cobalt Aluminum Oxide (NCA)
- Lithium-Ion Manganese Oxide (LMO)
- Lithium Nickel Manganese Cobalt (NMC)
Nickel-Metal Hydride Battery (NiMH)
NiMH batteries are a cheaper alternative to Lithium-ion batteries although the energy density ( Around 60-100 Wh/kg) is very low and the self-discharge rate is very high.
These batteries are good for hybrid cars where there is no need the charge the battery externally. It is charged only by the regenerative braking mechanism.
The regenerative braking mechanism converts some kinetic energy to heat while applying brakes. This recovered heat is used to charge the battery.
NiMH batteries are sufficient for light battery applications where the battery is not the only source of power for driving the vehicle like Full Hybrid cars.
NiMH batteries are safe for EVs and do not explode at high temperatures. The typical lifespan of NiMH batteries is around 4-5 years and lasts for 100K-150K miles.
Lead Acid Battery
Lead Acid battery is the oldest battery technology ever used in EVs. The technology was invented back in 1860 and was used in EVs until 1980.
It was then replaced by NiMH and Lithium Ion batteries as they offer better energy density and low discharge rate. However, NiMH batteries are cheap and offer high efficiency.
The battery that you see in your IC engine vehicle is mostly lead-acid batteries. It has a life span of around 3 months to two years and a regular checkup of electrolyte solution is required to improve the life. Lead acid batteries are recyclable.
Things To Consider While Choosing A Battery Type for EV
Choosing the right battery type is essential when you choose an electrical vehicle. As I said before for EVs, the battery is the heart of the machine. Any wrong selection will cost you in the future.
Here are some of the parameters that you should consider while choosing a battery for an EV.
Range
The number of miles a battery can hold charge is called the range of the battery. If a battery has a high kWh rating, does not mean that it will offer a better range.
It all depends on the battery types, how cells are contained in the battery pack, and how optimized the Battery Management System is.
Due to high energy density, lithium-ion batteries offer the best possible range with a limited space available in an electric vehicle
Life Span
Life space plays a big role in choosing the battery types of EVs. A typical lithium-ion battery lasts for around 160K-200K KM which is good for 8-10 years. Whereas a NiMH may last only for 3-5 years.
Battery replacement is costly ( Often 50% of the vehicle cost) and that is why choosing the right battery type is the need of the hour. Please remember that even the best type of battery will also degrade at the rate of 3-5% per year.
Safety
New generation EVs are much safer than before due to the use of the right battery type. We all might have heard about EVs catching fire but never know what was the reason behind those incidents. It could be the wrong battery or these batteries were exposed to harsh environments.
Battery types like lithium-ion and NiMH can survive high temperatures and up to a certain extent can withstand water. EVs with these battery types can be exposed to harsh conditions considering we are operating beyond safety limits
Cost
I feel, that when you consider the range, life span, and safety, you need to sacrifice the cost parameters. All other parameters come into the picture at a cost. Either you pay a little more and get a safe battery or go for cheap batteries and sacrifice safety.
Conclusion: Electric Vehicle Battery Types
90% of EVs in the market today use lithium-ion batteries. This is because these are safe, can offer battery energy density in a given space, and last almost for the life of the vehicle.
But Lithium-ion batteries come at a cost which is almost half of the price of the vehicle. New technologies are evolving and we might see better battery technology that is cheap, safe and takes less time to charge.
What Type Of Batteries Do Electric Cars Use?
Most electrical vehicles use lithium-ion batteries as they are safe, can withstand high temperatures, offer high energy density, and can last for a long time due to their low self-discharge rate.
