Toyota to Unveil Lithium-Ion Powered Prius Plug-In Hybrid

Toyota will unveil its long anticipated plug-in hybrid Prius at the Frankfurt Motor Show. In early 2010, over 500 Prius PHEVs will be leased to fleet customers in Japan, the United States, and Europe. These pre-production cars will let Toyota evaluate their performance in a real-world environment before full-scale production starts. Retail sales are planned for 2012. Toyota will also glean market intelligence on consumer response to the model as well as which characteristics they find appealing, and why.

The Prius Plug-in Concept's powertrain is like the Hybrid Synergy Drive system already used in the latest third generation Prius. The biggest change is a new high-output lithium-ion battery, a first for a Toyota hybrid, which replaces the nickel-metal-hydride battery pack now used. The Li-ion battery is more compact and has a higher volumetric energy density, meaning reduced vehicle weight and more efficient packaging.

Another advantage is that the Li-ion battery can be recharged much more rapidly than the NiMH battery. The battery in the Prius Plug-in can be fully recharged in an hour and a half from a 230 volt power source and in three hours when connected to a 110 volt source.

The PHEV Prius can operate in electric-only mode for about 12 miles at speeds up to 60 mph or so. This is about seven miles more than the current non-PHEV Prius. Apparently, this battery capacity was sized for European rather than American commuting habits. According to Toyota’s research, in the UK about 80 percent of trips are less than 6 miles and in France this number is 15 miles. For American commuters, the typically used all-electric commuting number is a much more demanding 40 miles, which is the all-electric capability of the Chevrolet Volt.

For longer distances or when the battery capacity limit is reached, the system automatically shifts to the conventional gasoline-electric full HSD mode. By adding PHEV capability, CO2 emissions are reduced to about two-thirds that of the non-PHEV version. There is even greater CO2 savings if the electricity used to charge the battery comes from renewable wind or solar sources.

The Prius PHEV is equipped with a Hybrid System Indicator that provides information on electric driving range based on the level of battery charge. An engine starting point display has also been added to emphasize the increased electric driving range. An Electro Multi-Vision screen displays the plug-in hybrid's contribution to reducing CO2 emissions via a computer graphic image of tree that gradually increases to a whole forest as the battery is charged.