Electric cars are regularly perceived as being slow and heavy. Recently, an Uber driver told me that he would consider buying an electric car only if the electric motor had better torque. He was confident that an internal combustion engine (ICE) has a better torque profile than an electric motor. I tried to explain that it is the combustion engine that is stopping today’s hybrids from performing better… but I failed miserably. I hope I do a better job now explaining why that is the case and why hybrids might be improving the perception of all electric vehicles (EVs) in future. There is some hope for EV perception outside battery electric vehicles (BEVs) like Tesla. It lies in a category called EREV (extended-range electric vehicle).
GM is trying to establish a differentiation between PHEVs (plug-in hybrid electric vehicles) and EREVs (like the new Chevy Volt). At first sight they might seem to be the same; both have an electric motor and a combustion engine; both have a battery pack with between 5 and 20kWh. The big difference, in simple terms, is that EREVs only use the internal combustion engine as backup when batteries are empty. The engine only starts when the battery is empty. Now, that might sound like a disadvantage (why would I only engage one motor instead of two?) but lets look at the data.
The Ford Fusion has a 7.6 kWh battery pack while the Chevy Volt has a 18.4 kWh battery pack. Thus, the Volt carries around a 140% larger battery pack. When looking at the graph above we can see that the larger battery pack combined with the EREV operations (either engine or motor is on) significantly reduces emissions on the EREV. I added another column, a theoretical third vehicle (in the middle). What if the Ford FusionEnergi had a 18.4 kWh battery pack? Assuming linear improvements for the PHEV (it is not correct, but represents a maximum for emissions), it becomes clear that the EREV still saves more gasoline and reduces emissions.
Two main take-aways:
1. The size of the current PHEV battery packs is two small to have a significant impact on emissions or gasoline consumption.
2. By allowing the electric motor to do most of the work (on the frequent short trips and commutes) a significant reduction of emission and gasoline consumption can be achieved.
What about performance though? Why does the friendly Uber driver still think so badly about the performance of hybrids?
When most people thing about EVs they refer to the best selling EV category called hybrid electric vehicle (HEV). HEVs, like the Toyota Prius C, are not plugged in for charging but rather they charge themselves through regenerative braking and other motion based charging technologies. That combination improves MPG, but the performance suffers as an electric motor correlates highly with the size of the battery pack! All EVs with small electric motors and small battery pack have poor acceleration. On the other hand the performance of an ICE hardly correlates with the size of the gasoline tank.
So, how do EREVs improve the perception of EVs again?
Simply, by improving the driving experience through an increased battery pack and engaging the electric motor for most of the trips. The ICE is used solely as a backup solution, when the car runs out of charge.
The Volt running off electricity is a fun, smooth and quiet driving experience...
What Chevy did with the Volt is redefine the driving experience of a PHEV, more so than actually inventing a new category of EVs. They decided to not only increase the size of the battery pack and electric motor but also use them primarily (and thus keeping the combustion engine relatively small). The battery is placed in the middle of the car, where the transmission and driveshaft of an ICE (internal combustion engine) car usually sits. This allows GM to compensate for the increased size of the battery pack.
With the average trip in the US being 9.79 miles, the Volt allows for at least 5 trips without engaging the combustion engine. That does not only reduce emissions and saves money, but also significantly improves the driving experience. The instant torque of the electric motors gives customers pure driving pleasure. With its improved MPG and better driving experience (for the most part) EREVs seem to be the future of PHEVs; a smarter way to use the same core technology. Current customers and experts think highly of the new Chevy Volt. But the Volt is more than just a good PHEV, it is the best advertisement for electric powertrains and will ultimately help upsell customers into BEVs.
Sini Ninkovic analyzes the EV market and its customers since 2012. He helped bringing BMW's i3 and i8 to market and currently works as Product Planner for Lucid Motors.