What is PHEV? How does PHEVs work? What PHEVs can I buy? So many questions about PHEVs. Let us dive right in.
Contents
- What is PHEV?
- How does a PHEV work
- PHEV History
- PHEV Cars
- PHEV SUVs
- Technology of PHEV
- PHEV Battery
- PHEV engine
- Fuel efficiency
- Hybrid Market
- Frequently Asked Questions
What is PHEV?
A plug-in hybrid, or PHEV, is an electric car that is effectively a bridge between a conventional hybrid and a fully electric vehicle. PHEVs are hybrid vehicles with a high capacity rechargeable battery and a diesel engine with an electric motor.
In contrast to conventional hybrids, PHEVs can store enough energy to drive an extended distance using electricity reducing their petroleum usage.
Some PHEVs can travel more than 70 miles on electricity alone and under typical driving conditions, store enough electricity to cut their gasoline use.
When the battery is drained, the conventional engine takes over and the car operates as a normal vehicle. Most PHEVs are passenger cars, but there are also PHEV versions of commercial vehicles and vans, utility trucks, buses, trains, motorcycles, scooters, and military vehicles.
Plug-in hybrids provide fuel and cost-efficiency for hybrid models along with the all-electric capabilities of battery-electric.
The PHEV also produces a cleaner energy source reducing global warming pollution than their fuel only counterparts. They don’t emit any tailpipe pollution when driving on electricity, and they gain fuel efficiency benefits from having an electric motor and battery.
How does a PHEV work
Plug-ins generally come with a medium-sized lithium-ion battery pack that’s connected to an electric motor. The lithium-ion batteries have to be plugged into the power grid to recharge.
In addition to the external electric power source, an internal combustion engine or regenerative braking can charge PHEV batteries.
During braking, the electric motor acts as a generator, using the energy to charge the battery. The electric motor supplements the engine’s power; as a result, smaller engines can be used, increasing the car’s fuel efficiency without compromising performance.
When a PHEV is turned on, typically it starts up in an all-electric mode and operates on electricity until their battery pack is depleted. Most hybrids ranges vary from 10 miles to over 40. Some models shift to hybrid mode when they reach highway cruising speed, generally above 60 or 70 miles per hour. Once the battery is empty, the engine takes over and the vehicle operates as a conventional, non-plug-in hybrid.
However, the battery doesn’t have to be empty for the engine to come on. This can happen if the electric vehicle system is too cold or hot, or while features such as the heaters are on. In some cases, the engine will come on if petrol hasn’t been added for several months. This is often a sign for drivers to top up the car with newer fuel to avoid damaging the engine.
There are two basic plug-in hybrid configurations, according to the Department of Energy:
In series plug-in hybrids, or extended-range electric vehicles, only the electric motor turns the wheels and the gasoline engine generates electricity. Series plug-ins can run on electricity alone until the battery runs down. The gasoline engine then generates electricity to power the electric motor. These vehicles might use no gasoline at all for short trips.
In parallel or blended plug-in hybrids, both the engine and electric motor are connected to the wheels and propel the vehicle under most driving conditions. The electric-only operation usually occurs only at low speeds.
Here is a video about PHEV :
History of PHEV
The history of hybrid cars dates back over 100 years, since the beginning of the auto industry. Early hybrids were tinkered with several external power sources including fossil fuels, steam, electricity, and sometimes a combination of these things.
Engineer Ferdinand Lohner-Porsche produced the first hybrid vehicle in the year 1899.
However, UC Davis professor Andrew Frank built the first plug-in hybrid electric vehicle that can charge from a standard electrical wall socket.
The history of hybrid electric vehicles, however, began shortly after the dawn of the 20th century. Here are some of the highlights of that history:
The beginning
The Austrian Dr. Ferdinand Porsche, at age 23, built his first car, the Lohner Electric Chaise. The hybrid made its debut at the Paris exposition. It was the world’s first front-wheel-drive.
Porsche’s second car was a hybrid, using an internal combustion engine to spin a generator that provided power to electric motors located in the wheel hubs.
On battery alone, the car could travel nearly 40 miles. Although in the 1910s, hybrids sold poorly due to higher prices and less power than the conventional gasoline-powered vehicles.
Hybrids soon became outdated, beginning a nearly 50-year period where they were merely an afterthought.
In 1969, a very lightweight experimental hybrid car was coined. It ran entirely on electric power up to 10 miles per hour.
The concept commuter vehicle housed six 12-volt lead-acid batteries in the trunk area and a transverse-mounted DC electric motor turning a front-wheel-drive trans-axle. The gasoline-powered engine was connected to the trans-axle via a worm gear.
The car could be plugged into a standard 110 Volt AC outlet for recharging. From 10 to 13 miles per hour, it ran on a combination of batteries and its two-cylinder gas engine.
Above thirteen miles per hour, the GM 512 ran on gasoline. It could only reach 40 miles per hour.
Revived interest
In support of hybrids, the United States Congress introduced legislation that encourages the use of electric cars intending to curb air pollution. Unfortunately, the motion was not well embraced until the Arab oil embargo of 1973. The oil prices skyrocketed creating a new interest in electric vehicles.
In those days, nearly 85 percent of all American workers drove to work, soaring gas prices and declining supplies were a major concern. The U.S. Department of Energy ran tests on many electric and hybrid vehicles produced by various manufacturers, including a hybrid known as the VW Taxi produced by Volkswagen in Wolfsburg, West Germany.
In the late 1990s, a handful of all-electric vehicles were introduced. Here is an incomplete list of such vehicles :
- Honda’s EV Plus
- GM’s EV1 and S-10 electric pickup
- a Ford Ranger pickup
- Toyota RAV-4 EV.
Despite the enthusiasm of early inventors, the electric vehicles failed to attract widespread and the all-electric programs were dropped.
It was not until Toyota released the Prius in Japan in 1997 that a viable alternative to gas-powered vehicles was introduced.
The rebirth
While all the starts and stops of the electric vehicle industry in the second half of the 20th century helped show the world the promise of the technology, the true revival of the electric vehicle did not happen until around the start of the 21st century.
In 2000, the Electric Power Research Institute (EPRI) sponsored the Hybrid Electric Vehicle Alliance to promote and develop original equipment manufacturer commercialization of plug-in hybrid electric vehicles.
The first commercially available plug-in hybrid, the Volt has a gasoline engine that supplements its electric drive once the battery is depleted, allowing consumers to drive on electric for most trips and gasoline to extend the vehicle’s range.
In 2003, Renault began selling the Elect‘road, a plug-in series hybrid version of their popular Kangoo, in Europe. In addition to its improved engine, it could be charged using an external power source up to 95% range in about 4 hours. After doing well market-wise, in 2007 the Elect’road was redesigned
Around 2004, new battery technology began hitting the market, helping to improve a plug-in electric vehicle’s range. In addition to the battery technology in nearly all of the first-generation hybrids, the Department’s research also helped develop the lithium-ion battery technology used in the Volt.
There are plenty of benefits of lithium-ion technology, such as lighter weight and faster charging time. Looking farther into the future there is the possibility of improved nano-textured lithium-ion battery packs becoming available as well as yet another switch away from batteries completely to a newer technology called high-discharge capacitors.
Plans to improve the plug-in industry are in motion and automakers are doing their utmost to steer the future of PHEVs in the right direction. If we transitioned all the light-duty vehicles in the U.S. to hybrids or plug-in electric vehicles using our current technology mix, we could reduce our dependence on foreign oil by 30-60 percent, while lowering the carbon pollution from the transportation sector by as much as 20 percent.
PHEV Cars
With so many choices among most of the brands, you already know, from Audi to Volvo, it is easy to get confused when shopping around.
To cut through some of that confusion, let us look at them now, model by model.
Audi
Audi only offers one PHEV in the US, the A3 Sportback e-Tron. This smallish 4-door hatch offers most of the luxury the German brand is known for, as well as an engaging driving experience. Its relatively short driving range is just enough for those with a brief commute to get to work and back on a single charge. Anything past that and you will be relying on the gas engine for help. This electric variant of the popular A3 hatch carries 5-star safety ratings all around.
Toyota Prius prime
Toyota Prius Prime is a plug-in hybrid offering 25 miles of all-electric range. It has a US EPA fuel efficiency rating of 133 MPGe and a 54 MPGe when relying only on the gas/petrol system. The total combined range is estimated by the EPA to be 640 miles, which means that the model has few competitors out in the car segment that can compete on the pure range.
Hyundai Sonata and Ioniq PHEV
Hyundai Sonata PHEV offers a 99 MPGe US EPA combined fuel/energy efficiency rating; a 39 MPG gas/petrol-only fuel economy rating; and a US EPA certified an all-electric range of 27 miles per full-charge.
The Hyundai Ioniq PHEV is a normal sedan with the ability to drive as far as the hybrids. It has a granted US EPA combined fuel/energy-efficiency rating of 119 MPGe; a 52-mile gas/petrol-only fuel-efficiency rating; and a 29-mile real-world range. Out of all of the offerings out there, the 2018 Hyundai Ioniq PHEV is probably one of the best choices as far as value for the money.
Chevrolet Volt
The Volt represents the Chevrolet brand aggressively foray into a once unstable plug-in hybrid market. Newly available, the second generation of the car is improved in every way. It comes with a generous 53-mile all-electric range and an efficient gas/petrol engine. The Chevy Volt PHEV currently features a 106 MPGe combined US EPA energy/fuel efficiency rating and a 42-mile US EPA fuel-efficiency rating for operation when the battery pack is fully depleted.
Kia Niro
The 2018 Kia Niro PHEV features some impressive efficiency and performance specs — with the US EPA having granted the model a 105 MPGe combined energy/fuel efficiency rating and a gas/petrol-only fuel efficiency rating of 46 MPG.
The real-world all-electric range of the 2018 Kia Niro PHEV is 26 miles per full charge, and the total range is 560 miles per full charge + full tank. The model features 104 horsepower, 195 pound-feet of torque, and 91.4 cubic feet of cargo space.
Kia Optima
The 2018 Kia Optima PHEV possesses a US EPA combined fuel/energy efficiency rating of 103 MPGe, a gas-only efficiency rating of 40 MPG, and a starting price of $35,210. Sound familiar? Yes, its drivetrain is quite similar to the Niro PHEV. The US EPA-rated all-electric range for the model is 29 miles per full charge.
Honda clarity
The 2018 Honda Clarity PHEV is very arguably the best iteration of the Clarity platform for most people’s needs. It is also arguably one of the best plug-in hybrids on the market. The 47-mile all-electric range, the 110 MPGe combined fuel/energy efficiency rating from the US EPA, and the 42 MPG gas/petrol-only fuel economy rating all make the model fairly attractive.
Ford C-Maxi
The 2017 model year of the Ford C-Max Energi PHEV featured a 95 MPGe combined fuel/energy efficiency rating from the US EPA a 20-mile real-world electric range and a 39 MPG gas/petrol-only fuel economy rating.
Ford Fusion Energi
The 2018 Ford Fusion Energi PHEV features a 97 MPGe combined fuel/energy efficiency rating from the US EPA a 42 MPG gas/petrol system rating and an all-electric range of 21 miles per full charge. The total system output for the model is 195 horsepower, and the model is outfitted with 7.6 kWh battery packs.
PHEV SUV
Volvo XC90 AWD T8 PHEV
The 2018 Volvo XC90 AWD T8 PHEV possesses a 19-mile real-world all-electric range (as determined by the US EPA) a 62 MPGe combined energy/fuel efficiency US EPA rating and a 27 MPG gas/petrol-only fuel-efficiency rating.
BMW X5 xDrive40e
The BMW X5 xDrive40e is a plug-in hybrid in possession of a 56 MPGe combined energy/fuel efficiency rating from the US EPA; a real-world all-electric range of 14 miles per full charge; a 24 MPG gas/petrol-only fuel economy rating; and 309 horsepower + 332 pound-feet of torque.
Porsche Cayenne E-hybrid
The 2017 Porsche Cayenne E-Hybrid features a 46 MPGe combined fuel/energy efficiency rating from the US EPA; a 22 MPG gas/petrol system efficiency rating; and a real-world all-electric range of just 14 miles.
Range rover sport PHEV SUV
The battery pack gives the owners a 31-mile electric range, with a 297bhp 2.0-liter turbocharged petrol engine. Pairing it with a 114bhp electric motor means the official figures show consumption of 88mpg.
Mitsubishi Outlander PHEV SUV
The drivetrain combines a 2.0-liter inline four-cylinder engine with a pair of electric motors. Its EPA rated at 74 MPGe combined with a full charge and 25 MPG combined while running on gasoline. Its batteries can be charged up at home for an electric-only range of up to 33 miles.
Lexus RX
The RX is available with a 2.0-liter petrol engine, but the lack of a more economical diesel option means most buyers choose the RX 450h hybrid. This produces 308bhp and returns around 54mpg, although CO2 emissions are higher than some of the SUVs on this list.
Toyota highlander
The three-row Toyota Highlander Hybrid 4WD LE ($36,670) is EPA rated at 30 city / 28 highway / 29 combined MPG. The Highlander Hybrid’s drivetrain consists of a 3.5-liter V6 engine mated to a trio of electric motors. The net system rating is a healthy 306 horsepower.
Mercedes GLE 550e
The third German luxury brand on this list offers American buyers something special in both it’s GLE 550e SUV and S 550e large sedan. Much like the BMWs, these PHEVs are full of the tech and rich interior appointments expected from a luxury marquee. Cost starts at $66,300 for the GLE 550e, and $97,595 for the wider, longer, and more luxurious S 550e sedan. Expect immaculate safety scores for both models.
MINI Countryman Cooper S E ALL4
This small SUV is family-friendly, very cheap to run and still manages to be fun to drive. The mini cooper is fitted with a version of the 1.5-liter petrol turbo engine and an electric motor for a total of 221bhp. Not only is the Countryman PHEV quick – getting from 0-62mph in 6.6 seconds – it can drive on electricity alone for up to 26 miles.
Kia Niro SUV
The conventional styling lays a competent, spacious family car with a 1.6-liter petrol engine and an electric motor, producing 138bhp between them. Claimed economy is decent at 74.3mpg, while CO2 emissions of 88g/km mean 17% Benefit-in-Kind (BIK) liability for company-car drivers.
Technology of PHEV – How does PHEVs work?
A full electric vehicle uses its energy far more efficiently than a vehicle with an Internal Combustion Engine (ICE) and can drive about 2.5 times further with the same energy. For this reason, it is expected that the electric vehicle will replace the ICE vehicle in the long term.
However, in the coming 20 years or so vehicles will probably still be equipped with IC engines, possibly in combination with electric engines, because per unit of weight an ICE vehicle can still drive about 40 times further. In these 20 years, the IC engine is expected to improve substantially.
The key advantage of PHEV technology relative to full Battery Electric Vehicles (BEV) is fuel flexibility. PHEVs have no limitation of the driving range and if the recharging infrastructure is spatially or temporally unavailable, it does not restrict the use of the vehicle.
A possible drawback of the PHEV is that it contains two systems to propel the vehicle, making it more costly to build than a BEV. However, the car manufacturing industry expects that PHEVs will be introduced to the market first and that the switch to BEV could be made when the PHEVs are found to be economically and technologically viable.
To make the widespread use of PHEVs feasible, an infrastructure of recharging stations is needed. This infrastructure needs to be standardized in a way that every brand of Plug-in Hybrid Electric Vehicle can be recharged at every recharging station.
A plug-in hybrid operates in charge-depleting and charge-sustaining modes. Combinations of these two modes are termed blended mode or mixed-mode. These vehicles can be designed to drive for an extended range in all-electric mode; either at low speeds only or all speeds. These modes manage the vehicle’s battery discharge strategy, and their use has a direct effect on the size and type of battery required
Charge-depleting mode allows a fully charged PHEV to operate exclusively (or depending on the vehicle, almost exclusively, except during hard acceleration) on electric power until its battery state of charge is depleted to a predetermined level, at which time the vehicle’s internal combustion engine or fuel cell will be engaged. This period is the vehicle’s all-electric range. This is the only mode that a battery-electric vehicle can operate in, hence their limited range.
Mixed-mode describes a trip using a combination of multiple modes. For example, a car may begin a trip in low-speed charge-depleting mode, then enter onto a freeway and operate in blended mode. The driver might exit the freeway and drive without the internal combustion engine until the all-electric range is exhausted. The vehicle can revert to a charge sustaining-mode until the final destination is reached. This contrasts with a charge-depleting trip, which would be driven within the limits of a PHEV’s all-electric range.
Plug-in hybrid vehicles (PHEVs) have the potential to displace a significant amount of fuel in the next 10 to 20 years. The main barriers to the commercialization of PHEVs are the cost, weight, safety, volume, and lifespan (combined shallow/deep cycle life and calendar life) of the batteries. It is expected that more and more car manufacturers will bring plug-in vehicles to the market in the coming years.
PHEV Battery
Batteries need to improve in several aspects – durability, life expectancy, energy density, power density, temperature sensitivity, reductions in recharge time, and reductions in cost. Battery durability and life expectancy are probably the biggest hurdles technically to the mass commercial viability of EVs and PHEVs.
New battery chemistries with increased energy densities will enable important changes to battery design. Energy storage systems will require less active material, fewer cells, and less cell and module hardware. These advancements will result in lighter, smaller and cheaper batteries and hence EVs and PHEVs.
The following energy storage systems are used in PHEVs and EVs:
- Lithium-Ion Batteries
- Nickel-Metal Hydride Batteries
- Lead-Acid Battery
- Ultracapacitors
Let us now look at each one in detail.
Lithium-Ion Batteries
Lithium-ion batteries are currently used in most portable consumer electronics such as cell phones and laptops because of their high energy per unit mass relative to other electrical energy storage systems.
They also have a high power-to-weight ratio, high-energy efficiency, good high-temperature performance, and low self-discharge.
Most components of lithium-ion batteries can be recycled, but the cost of material recovery remains a challenge for the industry.
Most of today’s plug-in hybrid electric vehicles and all-electric vehicles use lithium-ion batteries, though the exact chemistry often varies from that of consumer electronics batteries.
Nickel-Metal Hydride Batteries
Nickel-metal hydride batteries used routinely in computer and medical equipment, offer reasonable specific energy and specific power capabilities. Nickel-metal hydride batteries have a much longer life cycle than lead-acid batteries and are safe and abuse tolerant.
These batteries have been widely used in hybrid electric vehicles.
The main challenges with nickel-metal hydride batteries are their high cost, high self-discharge and heat generation at high temperatures, and the need to control hydrogen loss.
Lead-Acid Batteries
Lead-acid batteries can be designed to be high power and are inexpensive, safe, and reliable. However, low specific energy, poor cold-temperature performance, and short calendar and cycle life impede their use.
Advanced high-power lead-acid batteries are being developed, but these batteries are only used in commercially available electric-drive vehicles for ancillary loads.
Ultracapacitors
Ultracapacitors store energy in a polarized liquid between an electrode and an electrolyte. Energy storage capacity increases as the liquid’s surface area increases.
Ultracapacitors can provide vehicles additional power during acceleration and hill climbing and help recover braking energy.
They may also be useful as secondary energy-storage devices in electric-drive vehicles because they help electrochemical batteries level load power.
The viable battery sizes depending on the innovators need to reduce emissions, fuel consumption, and running costs. The best choice of PHEV battery capacity depends critically on the distance that the vehicle will be driven between charges.
PHEVs require longer battery charge time and discharging cycles than other hybrids. However, unlike the typical HEVs, the PHEV batteries do not deplete completely. So far, the batteries are still facing many challenges including battery life, weight, heat emission, design issues, costs, and overall safety issues that need to be addressed. Yet, the inventors are promising an advanced battery technology in the near future.
PHEV batteries can be charged by an outside electric power source, by the internal combustion engine, or through regenerative braking. During braking, the electric motor acts as a generator, using the energy to charge the battery. Learn more about charging PHEVs.
PHEV fuel consumption depends on the distance driven between battery charges. For example, if the vehicle is never plugged in to charge, the fuel economy will be about the same as a similarly sized hybrid electric vehicle. If the vehicle is driven a shorter distance than its all-electric range and plugged in to charge between trips, it may be possible to use only electric power.
PHEV engine
PHEVs have an internal combustion engine and an electric motor, which uses energy stored in batteries. PHEVs generally have larger battery packs than hybrid electric vehicles have. This makes it possible to drive moderate distances using just electricity (about 10 to 50-plus miles in current models), commonly referred to as the “electric range” of the vehicle.
Plug-in hybrids have the potential to be even more efficient than conventional hybrids because a more limited use of the PHEV’s internal combustion engine may allow the engine to be used at closer to its maximum efficiency.
A Prius is likely to convert fuel to motive energy on average of about 30% efficiency. This is more than the engine of a PHEV-70 that operates far more often near its peak efficiency. Hence, the batteries can serve the modest power needs at times when the combustion engine would be forced to run well below its peak efficiency.
The actual efficiency achieved depends on losses from electricity generation, inversion, battery charging/discharging, the motor controller and motor itself, the way a vehicle is used, and the opportunities to recharge by connecting to the electrical grid.
Fuel efficiency Of PHEV
Hybrid electric vehicles (HEVs) typically use less fuel than similar conventional vehicles, because they employ electric-drive technologies to boost efficiency. Plug-in hybrid electric vehicles (PHEVs) and all-electric vehicles (EVs) are both capable of being powered solely by electricity, which is produced in the U.S. from natural gas, domestic coal, nuclear energy, and renewable resources.
HEVs typically achieve better fuel economy and have lower fuel costs than similar conventional vehicles. For example, the 2018 Honda Accord Hybrid has an EPA combined city-and-highway fuel economy estimate of 47 miles per gallon, while the estimate for the conventional 2018 Accord (four cylinders, automatic) is 33 miles per gallon.
PHEVs and EVs can reduce fuel costs dramatically because of the high efficiency of electric-drive components. Because PHEVs and EVs rely in whole or part on electric power, their fuel economy is measured differently than that of conventional vehicles.
Miles per gallon of gasoline-equivalent (MPGe) and kilowatt-hours (kWh) per 100 miles are common metrics.
Depending on how they are driven, today’s light-duty EVs (or PHEVs in electric mode) can exceed 100 MPGe and can drive 100 miles consuming only 25-40 kWh.
The fuel economy of medium- and heavy-duty PHEVs and EVs are highly dependent on the load carried and the duty cycle, but in the right applications, they can maintain a strong fuel-cost advantage over their conventional counterparts.
Hybrid Market Size
How big is the hybrid market size? Is it big enough yet to make a dent in the overall car market?
The graph above shows top-selling hybrid cars as of 2017. This includes all HEVs including some PHEVs. But how is the hybrid car sales trend?
Let us look at another graph to answer that question.
All that is interesting. 2013 seems to have been the highest and best year for hybrids. What accounts for the sudden drop in sales since then? If you know the answer to that question, please comment below.
Since this post is about PHEVs, let us look at the graph for PHEVs in 2017.
Comparison: PHEV vs BEV
For a complete comparison between PHEV and BEV, check this article out.
| PHEV | BEV | |
| Engine | Uses gas ICE and Electric | Only Electric |
| Range | Use gas for long trips | < 100 miles |
| Price | Lower | Higher |
For comparisons with FHEV, go here
Here is another article about the differences between PHEV and MHEV .
Frequently Asked Questions
Plug in Hybrid Electric Vehicle