Electric Car Batteries 101
With petrol and diesel prices on the rise and an increased focus on sustainability, more and more people are making the switch to electric vehicles.
There are lots of myths about electric car batteries:
They don’t last very long (wrong)
Need replacing often (wrong!)
Are a significant fire hazard (wrong, again).
So we’re here, as industry professionals, to debunk EV batteries.
Our team at Electric Car Converts are EV fanatics and are here to help you understand everything there is to know about electric car batteries.
What kind of batteries do electric cars use?
The majority of EVs feature similar battery technology: tons of single cells stacked into groups to form one huge battery.
A lot of EV batteries are rather large, some even stretching a few meters in length and weighing several hundred kilograms; as a result, most are hidden beneath the floor of a car’s chassis, in a configuration known as a skateboard.
The individual cells within these battery packs are just a little bigger than a standard AA household battery!
There are 2 main types of batteries commonly used today:
Lithium-ion batteries are used by most EV makers (Tesla, Jaguar, Audi)
Lithium-ion batteries are rechargeable, consisting of cells where lithium ions travel between the negative electrode and the positive electrode via an electrolyte during charging and discharging.
The positive electrode of a lithium-ion cell is made of an intercalated lithium compound, while the negative electrode is usually made of graphite.
Lithium-ion batteries have a high power density, zero memory impact, and a low self-discharge rate. Cells can be designed to concentrate on either energy or power density.
As they can hold extremely high voltages and consist of flammable electrolytes, they must be handled with respect, by professionals with specialist tools and equipment to ensure they are safe.
Defective or inappropriately charged batteries can pose a fire hazard, so the technology that monitors them is extremely advanced and reliable, this is called a Battery Management System (BMS).
Nickel-metal hydride Seen in hybrids (eg Toyota)
Nickel-metal hydride (NiMH) batteries have increasingly supplemented previous nickel-cadmium batteries, which were phased out due to the growing environmental concerns.
Their cells consist of a positive cathode composed of nickel hydroxide, a negative anode made of various metal alloys that store hydrogen atoms, and a potassium hydroxide electrolyte solution.
A NiMH battery cell has a voltage of 1.2 volts. It is commonly found in cell devices, video recorders, emergency lights, machine tools, laptops, and hybrid vehicles, and is available and manufactured in both sealed and vented variants.
Nowadays, Lithium-ion batteries are by far the most widely used, this is due to them recharging quickly, being robust against temperature changes, and being able to maintain power for long durations, with bursts of very high power.
Electric Car Battery Capacity
EV batteries need to be relatively large to supply the energy needed to accelerate a vehicle weighing two tonnes or more, to motorway speeds, for hundreds of miles at a time.
The energy efficiency of a battery pack is generally expressed in kilowatt-hours, which denotes how much energy the battery can store over a given period of time. This is roughly equivalent to the size of a fuel tank in a combustion-engined vehicle.
So, a Tesla Model S with a 100kWh battery can supply a maximum of 100kW of power over an hour.
However, it would be no use if your car only worked for an hour, so an electric vehicle motor will consume significantly less energy than 100kW, thus the battery can last several hours and hundreds of miles before needing to be recharged.
The larger the battery pack, the longer range you will get, however, this is caveated by an added expense. Batteries are very expensive, so depending on your budget you may opt for a bigger or smaller battery capacity.
At Electric Car Converts, in our short-range builds, we often install just a 25kWh battery pack – which is more than adequate for an average day of driving in an electric converted classic car!
How Long Do Electric Car Batteries Last?
Battery degradation is a primary concern for drivers looking to drive an electric vehicle.
And so it should be! Electric cars are expensive enough without having to replace the entire battery pack every couple of years!
Recently, extensive research and technology have allowed battery manufacturers to significantly lower battery degradation, in other words, extend EV battery life, and allow batteries to maintain their capabilities over decades.
Remember your first smartphone (Nokia bricks..)? The battery used to be pretty much useless after a year or so, right?
Now, we never need to replace batteries in our phones. The same principle applies to electric vehicle batteries.
Lithium-ion batteries degrade based on charge cycles, Elon Musk claims that Tesla batteries will last 1500 charges, which equates to around 200,000 miles (range dependent).
This is longer than most diesel or petrol engines around today, which in that time will have to undergo extensive maintenance and servicing.
This longevity is down to the constant monitoring of each cell of a battery pack during charging and discharging by the BMS.
EV Battery Design Updates
If the cells are working too hard, getting too hot, getting too cold, or are under or over their voltage range they are shut down, allowing them to recover before they break.
Yet, even in the rare instance where a cell does break, it simply blows a fuse and is isolated from the rest of the battery pack, allowing the pack to continue to operate with a tiny bit less power.
Ultimately, battery degradation is a thing of the past, forget about it, batteries will last for decades, especially in a classic electric car!
Beyond their 1500 charges and useful lifespan in a vehicle, electric vehicle batteries can be used for energy storage where performance isn’t so important. For example, they can be used in motorhomes to store solar power, or as a backup for a power cut in our homes.
Why are electric car batteries so expensive?
The primary reason for the high cost of EV batteries is the materials used to manufacture them. Each cell has a cathode electrode, which is the most expensive component of the battery.
They contain highly valuable and rare metals, meaning they are expensive to source and work with, inflating their price. It’s for this reason that electric automobiles are so costly as compared to their gasoline or diesel counterparts.
It’s not all bad news though, electric vehicle batteries have drastically reduced in price over the years. It’s highly likely that this price decrease will continue as technology becomes more advanced, so less precious materials have to be used, and as more EVs are on the road, economies of scale will come into their own.
The more affordable battery technology becomes, the more likely drivers are going to be able to afford to switch to EVs, therefore reducing the environmental impact of cars and transport – so this is at the forefront of manufacturers’ strategies.
Who owns the battery in an electric car?
These days, you own the battery in your electric car, however in the early days of electric vehicles companies would sell you a vehicle but contract the batteries independently.
Renault was one of the brands that used this technique, although it is now nearly universally abandoned.
It was a technique to make EV’s appear less expensive at first glance, but you’d be locked into a monthly lease agreement, incurring finance on the battery in the same way you’d cover costs of your smartphone or Netflix over several months in a membership contract.
There is a theory however that the industry will go back to leased battery packs, although this could be on a very short scale. For example, rather than charging your own battery, you could go to a petrol station (kind of thing) and replace your empty battery with a pre-charged battery.
This could be swapped into your car in a matter of seconds and you could be back on your way. Perhaps a valid solution to range and charge times?
Are there any environmental impacts?
Electric car batteries are thoroughly tested, and manufacturers include numerous safety features to ensure that they are secure and safe for use over decades.
Of course, as they’re made out of precious and often poisonous materials there is always a risk of environmental damage.
At the end of their useful life, if recycled appropriately, materials in a battery can be used in another new battery time and time again, howeve,r if not disposed of properly they can be very dangerous and hazardous to the environment.
It is important to remember, however, that we’ve been driving around in cars fueled by fossil fuels, full of engine oil and nasty coolants for over a century.
So as long as these substances are used and disposed of safely, the environmental impact can be kept to a minimum.
Numerous studies have demonstrated that, while electric vehicles are more costly to construct, they are beneficial to the environment over their entire lifespan.
When an electric vehicle approaches the end of its life cycle, the precious batteries can be retrieved and repurposed to conserve energy.
Check out Electric Car Converts!
Electric car batteries are crucial to the future of motoring, and they’re going to become more popular and more advanced as time goes on.
It’s important to understand electric car components and what to look for in terms of batteries when purchasing an electric vehicle, as ultimately, they’re the most important part of the entire car!
If you have any questions regarding electric car batteries or electric car conversions, feel free to give us an email or a call, our friendly team at Electric Car Converts will be more than happy to chat all things EV!