Electric batteries power the electric motors of hybrid electric vehicles (HEV) and electric vehicles, also known as EVs. Typically, these batteries are Lithium-Ion because they are uniquely constructed for high kilowatt-hour capacity. However, electric cars also use lithium polymer, lead-acid batteries, and nickel-metal hydride batteries, but the percentage is relatively low compared to Lithium-ion batteries. So, why do electric vehicles prefer lithium-ion batteries to other battery types?
Lithium-ion batteries are preferred for electric vehicles because they have a high energy density or high energy per unit mass. In addition, the batteries are rechargeable and have long charge/discharge cycles. Modern lithium-ion batteries are now built with more fire resistance capability, rapid charging features, and lasts longer than ten years. EV manufacturers, such as Tesla, build their vehicles using variations of Lithium-ion batteries to deliver more energy.
Do Electric Cars Use Lithium Batteries?
Electric cars use deep-cycle batteries, which include lithium-ion batteries because they can be sustained over a long period. Unlike conventional petrol-powered only vehicles that have high specific energy, which makes it possible to have more range, electric vehicles have much lower specific energy, and that’s why their ranges are lesser. Specific energy or gravimetric energy is the energy per unit mass. It’s used to quantify stored heat, internal energy.
Most electric cars built today use lithium-ion batteries because of what they offer. Unlike other rechargeable batteries like nickel-metal hydride and lead-acid batteries, lithium-ion batteries have a high power-to-weight ratio, energy density, and above all, light, so that the weight of the vehicle is minimal.
The demand for lithium-ion battery increased since the late 1990s due to electronics, mobile phones, and laptops. As a result of the advances in this type of battery, electric vehicles manufacturers took advantage. Lithium-ion batteries were undisputedly the best because they corrected most flaws that existed in other types of rechargeable batteries – shorter lifespan and high discharge rate.
Why Are Lithium Batteries Preferred for Electric Cars?
Compared to other EV batteries, Lithium-Ion batteries have a longer lifespan. In addition, they are environmentally friendly, have more fire resistance ability and rapid charging, high energy density, and extended charge/discharge cycles.
Before now, most EVs used lead-acid batteries as a power source because of their low cost and availability. Due to their low costs, the total price of the EV was significantly lower than Lithium-Ion batteries. However, they have a shorter lifespan, with the batteries needing replacement every two to three years. This is why most modern EVs and hybrid vehicles adopted Lithium-Ion batteries as a power source.
Another type of rechargeable battery that has undergone development is nickel-metal hydride batteries. This battery has more stored energy than lead-acid batteries, and even lasts longer, as evident in some hybrid cars like the Toyota Rav4 EVs. However, they still share some of the flaws in lead-acid batteries – high self-discharge rate, poor efficiency, and demanding charge cycles. They also perform poorly in cold weather.
All these flaws were corrected in Lithium-Ion batteries. Although Lithium-Ion batteries are unarguably the best EV battery type, they are not near perfect. For instance, they are sensitive to temperature. Prolonged exposure to heat could degrade them, resulting in a lower lifespan. They also pose fire safety risks if charged improperly. Low temperature affects their performance, but their performance depends on the driver.
More work is still being carried out to improve the performance of Lithium-Ion batteries, most especially in the areas of energy density. If succeeded will result in more mileage of the electric vehicles.
How Long Do Lithium Batteries Last In Electric Cars?
The lifespan of Lithium-Ion batteries is usually long. For those considering switching to electric vehicles, Lithium-Ion batteries can last up to ten years before needing replacement. Some batteries, like Tesla Model 3 last up to 17 years, according to Consumer Reports.
Based on mileage, Lithium-Ion batteries last more than 100,000 miles. Tesla Model 3 battery, on the other hand, can last up to 500,000 miles.
Do Electric Cars Lose Charge When Parked?
This topic has gotten many worried because EVs are meant to be driven regularly.
Yes, electric cars lose charge when parked, but the loss is not that significant. If an electric vehicle is left unplugged, the pack will drain by a few percent of the total capacity per month. A fully charged electric car can stay for months until the battery is completely drained. Just imagine charging your phone to 100% and leaving it on standby. It will take a month plus before the battery reads 0%. The EV is just like your mobile phone, only that it’s built with longer battery life.
However, the rate of dropping depends on some factors. For example, if several power-sapping features like automatic preconditioning are turned on, the power drain would be more. Luckily, some EVs have features like “Deep Sleep” and “Power Save” modes that you can activate to prolong the battery life and conserve energy use in the long term.
Should I Charge My EV to 100%?
A lot of experts, including car manufacturers, have voiced their opinions regarding this. Ford and Volkswagen suggest charging your EV to 100% if you need it at the full range for longer trips. Nissan and General Motors, on the other hand, say that you can charge your EV to 100% any time, any day.
In fact, it’s safe to leave your EV plugged in overnight. Electric vehicles have some inbuilt management systems to mitigate the risks of overcharging, so car owners can wake up in the morning to see their cars fully charged, but not overcharged.
Some cars never truly charge up to 100% full capacity, even if the computer system tells you so. The reason for this is to preserve the battery life. Auto manufacturers have these systems do their bidding to prevent the battery from degrading faster. If a battery truly charges to 100%, the battery will be less productive, have a shorter life, and above all, lose its charging capacity.
You should never be worried that your EV is 100% charged because it isn’t. At most, it should be between 90-95%. So, take advantage of the long night hours to charge your EV to “100%” and get ready for the next day’s activities.
As much as you need your car charged fast to meet a work deadline or reach your destination quicker, you should avoid fast-charging your EV. According to a study published by the University of California, Riverside, using commercial fast-charging stations can damage EV batteries because they subject them to high temperatures and resistance. A battery may be fully charged, but the overall battery life will depreciate.
Technically, it’s not the fast charging that results in the battery’s decline. It’s the temperature. Fast-charging generates lots of heat on the battery, and while this is good, prolonged exposure to the high temperature can reduce the lifespan. If the EV’s battery management systems (BMS) aren’t active to bring the temperature down to a reasonable level, the battery life will be affected. This is why it’s recommended not to opt for fast-charging stations.
Is There an Alternative to Lithium-Ion Batteries?
Judging by the success of Lithium-Ion batteries, one could say that it would take some years before manufacturers can come up with better alternatives. Luckily, that’s already happening, thanks to the evolving cutting-edge technology.
Sooner than later, these alternatives will take over the world, and Lithium-Ion batteries would be yesterday’s news. So, what are some of these alternatives?
- Redox Flow Batteries
The Department of Energy’s Pacific Northwest National Laboratory has stated that Redox Flow Batteries are the future, and there’s no doubt about that. This type of battery comprises hydrochloric acid and sulfuric acid, and prototype batteries made from the addition of the compounds are found to have 70% more energy density than Lithium-Ion batteries.
Redox Flow Batteries are aimed for commercial purposes and could power a car up to 1000 miles on a single charge. That’s two times more than Lithium-Ion batteries.
- Lithium-Sulfur
Researchers say that Lithium-Sulfur batteries will have a 40% higher energy density than Lithium-Ion batteries at a lower cost of production. The downside of this type of battery is that they degrade quickly, but serious work is being done to make it more efficient. They could go on sale in a few years.
- Aluminum-Graphite Batteries
Although the voltage isn’t enough for cars, aluminum-graphite batteries could reduce charging times by almost 40%. Comprising of negatively charged aluminum and positively charged graphite, this battery is safe, lightweight, and has more energy density. They are still being worked upon for commercial use.
Other alternatives include:
- zinc-ions,
- sodium-ion,
- graphene supercapacitors,
- and bioelectrochemical batteries.
What If My EV Runs Out of Charge?
If your EV runs out of charge on the road, a car can tow your EV to the nearest charging station. You can also contact AAA to charge it. AAA trucks have Level 2 and 3 chargers that will provide up to 15 minutes of charge, enough to take you to the nearest charging station. The downside of AAA is that they are available in few locations.
In a Tesla vehicle, the computer can suggest the nearest charging locations. But, that only helps if the battery is not completely drained.
Finally
Lithium-Ion batteries are the most preferred type of batteries as far as EVs are concerned because of their efficiency, longer lifespan, and high energy density. However, sooner than later, they would be replaced by more efficient batteries, so that your vehicle will witness an improved performance.