Hybrid Car Battery 101: How it Works & How Long it Lasts
Hybrid car batteries don’t have to be a mystery. Even though this fuel-saving automotive technology has been on our roads since the late ’90s, most people don’t know how hybrid batteries work, how long they last, how to care for them or how replacements work.
Fundamentally, a battery is a device that stores electricity to be discharged (used) later. Batteries do this by charging metals and fluids within them, but exactly which metals and fluids are in each kind of battery makes a difference.
Fundamentally, a battery is a device that stores electricity to be discharged (used) later. Batteries do this by charging metals and fluids within them, but exactly which metals and fluids are in each kind of battery makes a difference.
Types of hybrid batteries
A hybrid car is a type of electric vehicle (EV) — or electrified vehicle, to be more precise — that has not just a battery-powered motor driving the wheels, but also a gas-burning engine. So, a hybrid electric vehicle (HEV) can have a smaller battery than a fully electric car because it can be recharged by the gas engine or turned off completely when the engine is driving the wheels.
A plug-in hybrid electric vehicle (PHEV) is a hybrid that can have its battery charged through an external plug. PHEV charging allows hybrids to have a longer battery-only range. The Mitsubishi Outlander PHEV gets over 60 kilometres of EV-only range and can charge 80% in just 38 minutes, for instance.
Choosing the right electrified vehicle for your lifestyle means understanding what’s under the hood (or floor). The batteries will be either Nickel-Metal Hydride (NiMH) or Lithium-Ion (Li-ion).
A plug-in hybrid electric vehicle (PHEV) is a hybrid that can have its battery charged through an external plug. PHEV charging allows hybrids to have a longer battery-only range. The Mitsubishi Outlander PHEV gets over 60 kilometres of EV-only range and can charge 80% in just 38 minutes, for instance.
Choosing the right electrified vehicle for your lifestyle means understanding what’s under the hood (or floor). The batteries will be either Nickel-Metal Hydride (NiMH) or Lithium-Ion (Li-ion).
Nickel-Metal Hydride hybrid batteries (NiMH)
Nickel-metal hydride hybrid batteries are made from nickel-based cathodes, metal hydride anodes and potassium hydroxide electrolytes. That’s probably too much info for anyone but a chemist, but just know that this formula is especially robust and reliable. This type of battery is ideal for hybrid use and, because it’s also a less expensive type of battery, most hybrids built in the last 20 years or so stick to NiMH.
Even though NiMH batteries get hotter during operation, external temperature has less of an impact on battery performance. They don’t lose as much range in cold weather or require as much conditioning, which means heating or cooling batteries so they’re at optimal operating temperature.
They’re not able to hold quite as much energy in the same space as Li-ion batteries, but because they have an onboard generator (your engine and regenerative brain) to charge them, that’s less of a concern. NiMH batteries can stand up to charging and discharging often without degrading, or losing their ability to hold electricity. Still, the weight and size can be a challenge, and that’s why most fully electric cars — which need larger batteries — go with Li-ion over NiMH.
Another reason NiMH batteries make sense for hybrids, but not EVs, is because they can suffer from a memory effect in which they start to “think” they have less capacity than they really do. Battery management systems are great at managing this in hybrids. On an EV, that memory effect would be harder to manage, since there’s no gas engine to give the battery a break.
If you buy a used hybrid, you’re almost guaranteed to get one with a NiMH battery. Newer hybrids, however, are beginning to use Li-ion batteries as the technology matures.
Even though NiMH batteries get hotter during operation, external temperature has less of an impact on battery performance. They don’t lose as much range in cold weather or require as much conditioning, which means heating or cooling batteries so they’re at optimal operating temperature.
They’re not able to hold quite as much energy in the same space as Li-ion batteries, but because they have an onboard generator (your engine and regenerative brain) to charge them, that’s less of a concern. NiMH batteries can stand up to charging and discharging often without degrading, or losing their ability to hold electricity. Still, the weight and size can be a challenge, and that’s why most fully electric cars — which need larger batteries — go with Li-ion over NiMH.
Another reason NiMH batteries make sense for hybrids, but not EVs, is because they can suffer from a memory effect in which they start to “think” they have less capacity than they really do. Battery management systems are great at managing this in hybrids. On an EV, that memory effect would be harder to manage, since there’s no gas engine to give the battery a break.
If you buy a used hybrid, you’re almost guaranteed to get one with a NiMH battery. Newer hybrids, however, are beginning to use Li-ion batteries as the technology matures.
Lithium-Ion hybrid batteries (Li-ion)
Li-ion batteries also use similar construction with an electrolyte solution, but the metal they use is lithium. Chemistry aside, this formula is more energy dense than NiMH, meaning it can store more electricity in the same space. Some hybrids, especially plug-in hybrids with slightly larger batteries, have Li-ion batteries. However, due to their higher cost, the benefits of Li-ion hadn’t made sense for hybrids over the past 20 years.
Li-ion has also had to overcome other challenges to fit hybrid applications better, even though they’ve been powering smaller devices like laptops and phones for decades. But just like your smartphone battery is sensitive to temperature and charging/recharging, so are Li-ion hybrid batteries.
With greater power and efficiency, plus a longer lifespan, Li-ion batteries represent the future of hybrid battery technology.
Li-ion has also had to overcome other challenges to fit hybrid applications better, even though they’ve been powering smaller devices like laptops and phones for decades. But just like your smartphone battery is sensitive to temperature and charging/recharging, so are Li-ion hybrid batteries.
With greater power and efficiency, plus a longer lifespan, Li-ion batteries represent the future of hybrid battery technology.
Other battery tech in hybrids
The main traction batteries aren’t a hybrid's only electricity storage device. They still have a standard 12-volt automotive battery, which is usually lead-acid, to handle:
- Starting the engine;
- Powering the hybrid system’s computers;
- Powering always-on features like security systems and connectivity; and
- Providing electricity for emergency features like hazard lights and communication systems.
While NiMH and Li-ion cover the consumer car market, other electrified car batteries are being developed to go even longer ranges, such as dual-chemistry batteries using graphite and silicon.
Supercapacitors, which are used to provide electricity in short but powerful bursts, also show promise in both existing mild-hybrid systems and future ultra-efficient vehicles. Another option is the solid-state battery, with its liquid-free chemistry. Solid-state batteries can be powerful but still light, and weight is everything when it comes to efficiency. Many battery chemistry advancements are supported by Canada’s own industries for manufacturing as well as sourcing minerals like graphite, cobalt, copper, aluminum and more.
Maintaining hybrid batteries: can you improve battery longevity?
The state of battery technology today estimates that batteries for fully electric vehicles should last at least eight to ten years or 160,000 kilometres. In regions without extreme hot and cold temperatures, which are hard on batteries, that estimate extends another 50% to 240,000 kilometres.
But hybrids are different — they don’t use the battery all the time. The battery’s not as large as those in an EV, and it isn’t charged and discharged as much or as often. Because of this lighter use, hybrid batteries tend to last much longer. It’s not uncommon for hybrids to go well over 480,000 kilometres without needing a new battery.
But hybrids are different — they don’t use the battery all the time. The battery’s not as large as those in an EV, and it isn’t charged and discharged as much or as often. Because of this lighter use, hybrid batteries tend to last much longer. It’s not uncommon for hybrids to go well over 480,000 kilometres without needing a new battery.
Need more convincing? Taxi drivers have been using hybrid cars for more than 20 years all around the world. Longevity and durability is the name of the game in their business, and hybrids have proven up to the task — easily clocking hundreds of thousands of kilometres on their original battery packs. In one case, a driver put more than 1,000,000 kilometres on his original battery.
Hybrids also reduce brake wear and the cost for related brake maintenance, because much of the car’s braking is handled with the hybrid system’s regenerative braking instead. That means when the car is coasting, the electric motor is spun backward by the car’s momentum to charge the battery. Some hybrids, like the Outlander PHEV, even offer strong regenerative braking for one-pedal driving
Yes, you can drive and care for your car in a way that is gentler on the battery and could extend its life and preserve its range — but most of the responsibility falls to the Battery Management System (BMS)
Hybrids also reduce brake wear and the cost for related brake maintenance, because much of the car’s braking is handled with the hybrid system’s regenerative braking instead. That means when the car is coasting, the electric motor is spun backward by the car’s momentum to charge the battery. Some hybrids, like the Outlander PHEV, even offer strong regenerative braking for one-pedal driving
Yes, you can drive and care for your car in a way that is gentler on the battery and could extend its life and preserve its range — but most of the responsibility falls to the Battery Management System (BMS)
Trust your battery management system
A battery management system controls the charging, discharging and power output as well as whether the car will use the battery or the gas engine. The management system also controls the battery’s cooling system, because batteries get hot when charging and discharging. They also lose range when they’re too cold, so they actually have their own heaters controlled by the BMS.
The BMS will also report to the car’s main computer and to the mechanic’s diagnostic tools measurements about individual cells and overall battery health. Most hybrids work best when you just drive them normally and let the BMS sort things out. Keeping your 12-volt battery maintained, so the BMS never loses power, is a good practice.
Choose eco mode
Most hybrids have drive mode selections that can provide a more comfortable, sporty or fuel-efficient ride. Choosing the most efficient mode gives the BMS permission to go into its most conservative setting. This not only gives the best overall efficiency, but will also be gentlest on the hybrid battery.
Follow the service schedule
Just like with any car, following the recommended service schedule will help all your hybrid vehicle’s systems work most efficiently and last longer. In modern cars, service can also include software updates that can change settings on the BMS to give longevity or range benefits. Hybrid batteries also have their own warranties, similar to the traditional powertrain and bumper-to-bumper options.
Mitsubishi, for example, offers a 10-year/160,000-kilometrelimited warranty on the battery for its Outlander PHEV, as well as roadside assistance coverage and other options.
Batteries also last longer when they don’t work as hard. So, if axles, brakes or other drivetrain components are past their service life and stressing the vehicle, the battery might work harder and not last as long. That goes for tires, too – keep them at proper pressure and tread depth.
Mitsubishi, for example, offers a 10-year/160,000-kilometrelimited warranty on the battery for its Outlander PHEV, as well as roadside assistance coverage and other options.
Batteries also last longer when they don’t work as hard. So, if axles, brakes or other drivetrain components are past their service life and stressing the vehicle, the battery might work harder and not last as long. That goes for tires, too – keep them at proper pressure and tread depth.
Avoid fully draining the battery
While the BMS will protect the battery from ever going too low, try not to make it a habit to creep along on that last bar with an empty tank of gas.
Avoid short trips and aggressive driving
Short trips don’t allow the battery to warm up or cool down to optimal operating temperature. And when you stomp on the go pedal demanding full power, it puts high demand on the battery. If you limit your tendency for short trips and hard launches, your hybrid’s battery should last longer.
Ditch extra weight
Weight is an enemy to efficiency, especially for battery-powered cars. Since hybrids are already carrying more weight than their gas-only counterparts, you don’t want to throw off the equation by carrying a bunch of unnecessary cargo in the trunk. The same concept applies to accessories like a roof rack, which adds aerodynamic drag and makes the systems work harder.
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