For years we’ve had a little semantic squabble in the plug-in electric car field. General Motors insists on calling the Chevy Volt a range extended electric vehicle, while in truth it is a plug-in hybrid. But, point out that obvious truth in certain crowds is sure to cause outrage because GM has convinced them to call the Volt an electric car. A measuring stick we’ve used for a long time is this: “it’s not electric if you can’t plug it in” and by golly the Volt can be plugged in, making it an electric car. But there is also a well defined phrase, “plug-in hybrid”, describing a vehicle with two power sources working together to drive the car (the hybrid drive train) and which can be plugged in to recharge the battery pack. That’s what the Volt is, yet GM continually pushes this concept of a “gasoline engine range extender”.
GM has also repeatedly sold the Volt as the only solution for Range Anxiety. That’s because the gasoline range extender is the solution to the fear that is supposedly nagging in the minds of every battery electric vehicle owner. GM even went so far as to trademark “Range Anxiety” back in 2010. As recently as September 2015, GM’s suite of advertising included at least one pushing the idea of battery electric car owners being frozen by fear of range anxiety.
At the moment I’m writing some content intended for a book, and an idea struck me. There are many forms of “range extender” for electric cars. Gasoline engines are not the only thing which could be described as a range extender.
The effect of this thought is to diminish the value of the phrase “range extender”. GM’s Voltec drive train with the gasoline engine range extender is not the only method to achieve that end.
Consider:
- DC Fast Charging range extender: CHAdeMO or Combo Charging System or Supercharger can all quickly add range to an electric car. Generally speaking any charging station away from home (or work) is a range extender, but I think we all want this phrase to refer to devices that add range quickly. DC Fast Charging adds between 150-300 miles of range per hour of charging.
- Portable towable battery packs range extender: This is a design idea some have floated, to have a battery pack on a small trailer towed behind a car. One could easily rent the trailer for long trips, connecting it to a special charging port that allows the car to drive while the addon pack is plugged in. Battery trailer exchange stations could be located at stops along highways, similar to the propane tank kiosks seen at gasoline stations today.
- Battery swapping range extender: This concept is way older than Better Place and Tesla Motors, both of whom have implemented modern roboticized versions of the idea. Quickly exchanging a depleted pack for a fresh one certainly adds to electric car range. With a well designed station the battery exchange can be as fast as refilling a gasoline tank.
- Supersized battery pack range extender: Tesla’s approach to this problem was to use an extra-large battery pack, much bigger than was needed for around town driving. You then couple this with extra fast recharging capability. The Roadster had a 200+ mile range thanks to a 50+ kiloWatt-hour battery pack, and incorporated charging capable of
80 amp70 amp charging speed. The Model S took that to a whole new level with an 85+ kiloWatt-hour pack, supporting 250+ miles of range. (correction due to comment below) - Fuel Cell range extender: Fuel cell vehicles do have an all electric drive train, and a small battery pack to buffer electricity. Hence, it’s not that much of a stretch of terminology to call the fuel cell a range extender. There’s even some work to design fuel cell vehicles with larger battery packs where the fuel cell is used as a portable range supplement. The refueling speed for fuel cell vehicles has to do with the pressure generated by the station, and hydrogen level in its storage tank.
- Gasoline Engine range extender: These vehicles are what we normally use the phrase “range extender” to describe. The Chevy Volt, Fisker Karma, Via Motors VTRUX line all have explicitly used the phrase “extended range electric vehicle.” Many also use this phrase to describe the BMW i3 REX, and of course REX can be seen as an acronym Range EXtension. The refueling speed at a gasoline pump is very fast.
All these are methods to add range to an electric vehicle. What’s wanted for widespread electric vehicle adoption is an easy method to drive long distances.
So far long distance electric driving incurred a different tradeoffs. Each of the methods just named carry pluses and minuses. Some have been successful, some failed, while some never got off the drawing table.
All this suggests a different model for the phrase “range extender” than what GM told us.
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- The unextended range for an electric car is 80ish miles.
- Most plug-in electric cars use one of the above range extension methods.
- Some plug-in electric cars do not use any range extension method. (Fiat 500e, Smart ED, Ford Focus Electric, etc)
There you have it, my humble suggestion for reframing the phrase “range extender”. Maybe this will result in wiser discussion about how we can get more range and therefore better usability of our plug-in electric cars.
Let me know what you think in the comment box below.
UPDATE: (December 3, 2015) There was significant discussion on Facebook
and Google+ which had legitimate divergences from what I wrote above.
An example of one point comes not from those discussions, but a news report in which a Nissan executive said they’d add a gasoline powered range extended electric car shortly. The article made it clear Yoshi Shimoida, Nissan’s “deputy general manager”, drew a clear distinction where “range extended electric car” means a pure “series hybrid”. In a series hybrid the gasoline engine is solely used to recharge the battery pack, as is done today with the BMW i3 REX. Until now Nissan has depended on fast charging to support longer distance travel.
Which gets us to one of the misconceptions many have about the Chevy Volt. On G+ I was told in no uncertain terms:
The Chevy Volt is an electric car and driven only by the battery. If you disconnect the battery from the car, the gas generator can not propel the car. It is only there to charge the battery. So, it is by the purist sense of the wording, “range extended EV”.
That would be a wise observation if it were true. Instead, the Chevy Volt has always had a blended drive train where the gas engine really is mechanically connected to the wheels. This was first discovered back in mid-2010 when it was noted that to get optimum benefit, at certain speeds the Volt’s gas engine was connected directly to the wheels.
I described fast charging as a range extender, and that fails in a couple ways for several people:
- Range extenders work without the car having to stop — fast charging requires that the car stop at a charging station.
- The charging stations currently existing are haphazardly deployed and don’t really serve us very well.
The competitive disadvantage electric vehicle charging has to overcome is the ease of refueling for gasoline cars. Just a couple minutes for hundreds of miles of range.
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David. One small point the Roadster could only charge at 70A. The S can go up to 80A. Something about the J1772 protocol IIRC
Thank you for the correction