PHEVs

Besides fuel-cell (electric) vehicles (FCV), there are other vehicle concepts under development, which are also based on electric drives ranked by increasing battery involvement in the propulsion system, and thus extended battery driving range, these are hybrid-electric vehicles (HEV), plug-in hybrid-electric vehicles (PHEV) - which both incorporate an ICE - and, finally, pure battery-electric vehicles (BEV), without an ICE. While electric mobility in its broadest sense refers to all electric-drive vehicles, that is, vehicles with an electric-drive motor powered by batteries, a fuel cell, or a hybrid drive train, the focus in this chapter is on (primarily) battery-driven vehicles, i.e., BEV and PHEV, simply referred to as electric vehicles in the following. 

The large scale adoption of PHEVs (or BEVs) in Europe might create a regulatory issue as electric vehicles will shift C02 emissions from the transport sector to the electric power sector, which - unlike road transport - is covered by the European Emissions Trading Scheme (ETS), a compensatory mechanism or the inclusion of road transportation within the scheme would be required. 

Cycle life is another important factor because it determines the longevity of the battery in practical use. The number of lifetime cycles depends strongly on the so-called depth of discharge if only some 10-20% of the full discharge capacity is used (as in the Toyota Prius for instance) the batteries can handle millions of shallow cycles . However, for PHEVs or BEVs the number of deep cycles (typically 80% discharge) is a relevant characteristic. 

Today, there is a general consensus that in the coming two decades electric vehicles, i.e., PHEVs and BEVs, are going to gain a material share of the vehicle fleet in many countries. However, the upsides as well as limitations of electric mobility need to be addressed realistically. 

Equally, electricity can be generated from a wide variety of energy sources, and battery-electric vehicles have a far higher efficiency than fuel-cell vehicles, as the high discharge rate of the battery is almost double the efficiency of a fuel cell. Battery-electric vehicles or PHEVs are also advantageous, as they can rely on an existing supply infrastructure. 

Axsen, J., Burke, A. and Kurani, K. (2008). Batteries for Plug-in Hybrid Electric Vehicles (PHEVs) Goals and the State of Technology Circa 2008. Report UCD-ITS-RR-08-14. Davis Institute of Transportation Studies, University of California. 

Kempton, W. (2007). Vehicle to grid power. IEEE Conference Plug-in Hybrids Accelerating Progress, Washington, DC. www.ieeeusa.org/policy/phev/ presentations/Tutorial%20Kempton.pdf. 

Tahil, W. (2006). The Trouble with Lithium. Implications of Future PHEV Production for Lithium Demand. Meridian International Research, www.meridian-int-res.com/ Projects/Lithium.htm. 

PAFC PEMFC PFC PGM PHEV PISI PM POX ppm PPP Phosphoric-acid fuel cell Proton-exchange-membrane fuel cell Polymer-electrolyte membrane Perfluorocarbons Platinum-group metals Plug-in hybrid-electric vehicle Port-injection spark ignition Particulate matter Partial oxidation Parts per million Purchasing power parity... 

Electric Cars and Plug-in Hybrids (PHEVs) Will Quickly Gain Popularity... 

Toyota recently announced a PHEV version of its popular Prius to be ready for delivery by 2010. Daimler has been testing 40 of its Sprinter delivery vans developed Europe that utilize diesel-electric plug-in technologies. 

Figure 3.5.3 Ragone plot for different energy storage solutions. The stars show specific energy and power goals for different vehicle technologies (EV electric vehicle PHEV plugin hybrid EV HEV hybrid EV) compared to internal combustion (IC) engine. (V. Srinivasan, Berkeley Electrochemical Research Council). Used with author s permission.

FIGURE 12.1 Diagram of a plug-in hybrid electric vehicle (PHEV). 

---