How an EV’s main battery works
You’ll find many types of batteries in the industry: nickel-metal hydride (NiMH), lead-acid, lithium-ion, and more. Your disposable batteries at home are generally alkaline batteries. Rechargeable ones are usually NiMH type. Most EVs, though, have a lithium-ion battery.
All batteries have an anode, a cathode, and an electrolyte. The electrolyte reacts with the anode and cathode to create energy. When a battery charges, electrons travel from the cathode to the anode. When it discharges, the flow reverses.
One battery contains multiple battery modules, each of which holds a set of battery cells. In a lithium-ion battery, one cell comprises the following:
- anode (negative pole)
- cathode (positive pole)
- separator
- electrolyte (usually a lithium-salt solution)
Do EVs have other batteries?
Yes. Because an EV’s main battery uses higher voltage, the vehicle needs a secondary battery to power internal electronics, just like internal combustion engine (ICE) vehicles do.
For comparison, EVs run on a 400 V or 800 V battery, whereas the small lead-acid battery carries only 12 V.
For this blog post, we’re focusing on the high-voltage battery that powers the drivetrain.
How to know when it’s time to replace your EV’s battery
You’ve maintained your EV battery well, but you still suspect it’s time for a replacement. How can you find out?
EV batteries have two key measures that help auto technicians know if it’s time for a replacement: state of health and state of charge.
State of charge measures how much energy your battery can still carry. This is 100% when the battery is new, and it will decrease over the battery’s lifetime. If you’ve looked up how much juice your cell phone battery can still store, this is its state of charge.
State of health measures how well a battery performs now compared to a new one. This value combines measurements of charge acceptance, internal resistance, voltage, and self-charge.
State of health can also be ascertained by tracking the number of charge-discharge cycles a battery completes. However, state of health, unlike state of charge, is calculated through various means and is an estimate, not an exact value. Standardization efforts are underway.
Can the battery be repaired?
Always ask this question first. Sometimes a battery cell or module is damaged, and replacing it will bring your battery closer to its original performance.
Because the other cells have been in use this entire time, they are worn. But if tests show they’re performing at optimal efficiency for their age, then having the damaged cell or module replaced may be a viable – and much cheaper – solution.
How much does it cost to have your battery replaced?
This is where the horror stories begin. A quick search online will show you tales of drivers being quoted $50,000 to have an EV battery replaced.
EV batteries are by far more expensive than 12 V batteries, costing into the thousands. However, a little research here before you purchase your EV – if possible – can keep these rare but potential costs down.
The cost of replacing an EV battery can range from about $8,000 to over $30,000. However, because this event is rare, compare the price to replacing an ICE car’s engine. It may surprise you to find that an engine replacement costs more in many situations.
EVs today generally come with an eight-year or 160,000-km warranty. In many situations, then, your battery replacement will be covered up to those limits. Please read the fine print relevant to your vehicle and ensure you understand it before purchasing.
If you suspect you may need a new EV battery, contact your nearest NexDrive service centre for an estimate.
Are there cheaper options to replace my EV battery?
The good news about EV batteries is that many of the components are recyclable. Some are even serviceable. If your EV has lasted at least 10 years before you need a new battery, consider purchasing a used one. You can easily cut your replacement costs in half.
What should you expect when you have your EV’s battery replaced?
Unlike a 12 V battery, which any driver can replace in their driveway, an EV battery replacement must be done by a professional. Online instruction videos do not count. With EV batteries packing 400 to 800 V, the tiniest mistake by an amateur of any level can be deadly.
Also, ensure the automotive expert you choose has received special training in maintaining and repairing EVs. Although all cars take an energy source and turn it into power to make the car move, the actual process differs considerably between ICE vehicles and EVs.
This is not something a mechanic can learn on the fly. If you see the mechanic working on someone else’s EV without any noticeable safety equipment, for example, take your car elsewhere.
What happens to the battery after it’s been removed?
One of the biggest concerns with EV batteries is that they’re thrown out after they’ve met their demise.
Nothing could be further from the truth.
Like all recyclable materials, batteries can often be reused. What was once an EV’s energy supply can, with some maintenance and repair, become stationary energy storage for a home or a battery pack for an electric wheelchair or a drone, to name a few possibilities.
Current estimates say that new lithium-ion batteries last 10-15 years in a vehicle. Repurposed batteries may have another five to ten years left in them. Because EV battery use is still relatively new, more data needs to be collected to give more definitive ranges.
Much of this relies on recycling facilities, so ask your local EV technician what will happen to your car’s battery after they’ve removed it.
If you suspect your EV’s battery may need replacement, an expert at your nearest NexDrive service centre will be happy to talk to you.