At last month’s 2011 Detroit Auto Show, the wraps came off the new 2012 Toyota Prius V, a bigger and more practical version of the Prius hatchback that treads the line between wagon and minivan.

Despite the extra height, weight, and girth, however, the vehicle is still limited to five seats--just like the hatchback.

Toyota Prius fans in Europe, however, will be offered a new ‘Prius +’ model that looks identical. It comes with not only a pair of third-row seats, but also a more advanced--and compact--lithium-ion battery pack. It won't be available until after the U.S. model goes on sale, however.

The U.S.-market Prius V, due in dealerships this summer, will ship with Toyota's current nickel-metal hydride battery pack, which it has used in all its Hybrid Synergy Drive models to date.

The information was revealed by Toyota Europe’s vice president of product planning and marketing, Guillaume Gerondeau, who spoke recently with Autocar.

Gerondeau explained that the upcoming Prius V required a larger battery pack because of its less advanced nickel-metal hydride cells. This meant they had to be located under the rear load floor.

The European version, however, uses more compact lithium-ion cells, which meant engineers could store the battery pack in the front of the vehicle, leaving space for a third row of seats.

Gerondeau went on to explain that demand in the U.S. for the Prius was so strong that Toyota wanted to provide the bigger Prius V as soon as possible. He also said that U.S. buyers looking for seven-seat vehicles don’t typically shop in the midsize segment in which the Prius V sits.

The world debut of the European-market Prius + will be at the 2011 Geneva Motor Show, which kicks off on March 1. You can follow our full coverage of the event by clicking here.