A hybrid car is a car that is propelled by more than one energy source. Typically, when one is thinking of a hybrid car, it is usually a gasoline/electric hybrid, as that is what is currently available commercially. (There are diesel-electric concept cars (not in production), and there are diesel-electric locomotives, submarines, and heavy construction equipment...) Usually a dual-fuel vehicle, like a CNG-gasoline or LPG-gasoline vehicle isn't in the popular hybrid definition, but those are usually aftermarket-fitted anyways.
There are no commercially-available plug-in hybrids on the market so far. (So you cannot plug them in, other than the same gas station pump that most other regular cars use.) The hybrid battery is recharged either through regenerative braking (kinetic energy from coasting/slowing down spins a generator to make potential energy in the battery) or by taking excess power from the gasoline engine (use the gasoline engine as a generator) to recharge the hybrid battery. There is no plug.
How a hybrid car works depends on the technology that a manufacturer decided to use to make it a hybrid. Not all hybrids are created equal.
As the lowest common denominator, hybrids usually have a larger electric motor (for starting the gasoline engine or for charging the hybrid battery), larger/additional hybrid battery pack to drive the electric motor, auto-stop (gasoline engine turns off at idle), regenerative braking (coasting or light braking will cause the motor to act as a generator, capturing some of that lost kinetic energy of wheel motion and storing it as electricity in the hybrid battery), improved fuel economy, and lower emissions.
More improved hybrid systems allow for tuning for higher performance (more power or acceleration), or for more fuel efficiency (usually through using a smaller engine, where the electric motors help out). On the more improved hybrid systems, you could see:
- ability to act as a standing generator to power equipment off-site
- additional peak power, by the electric motor assisting the gasoline engine as required (for acceleration or hill climbing, for example), similar to a turbo
- electric-only propulsion (short periods of the electric motors/hybrid battery alone powering the car, for low power requirements (such as coasting, driving on the level, low speeds)
- reduction in weight and ability to move accessories from belt-driven to electrically-driven (smaller wires needed)
The Ford/Mercury hybrid system and the Nissan hybrid system is fairly similar to the older Toyota THS system (seen on the 2001-2003 Prius) - licensed technology from Toyota. Toyota/Lexus hybrids are currently using the THS-II or HSD (Hybrid Synergy Drive) system. Honda is using their IMA (Integrated Motor Assist) hybrid system. GM's newer hybrids are using their BAS (belt-alternator system) or two-mode system, while their older "hybrid" pickups are pretty much the lowest common denominator listed above.
For general overviews:
http://www.cartalk.com/content/features/…
http://auto.howstuffworks.com/question26…
http://www.howstuffworks.com/hybrid-car.…
http://www.fueleconomy.gov/feg/hybridtec…
http://www.edmunds.com/advice/hybridcars…
http://www.hybridcenter.org/hybrid-cente…
The problem is that not all hybrids are created equal. There are different hybrid technologies, depending on manufacturer. Even among the same manufacturer, you can find one model tuned for performance (power and acceleration) with only a slight fuel efficiency improvement, compared to another for fuel efficiency and emissions. (See the Honda Accord Hybrid vs. Honda Civic Hybrid, or the Lexus models compared to their sister Toyota models...)
So, who did the research and who made the technology depends on what hybrid system you are asking about, since each automobile manufacturer has a different technology that can be labeled as a "hybrid." To my knowledge, Toyota/Lexus and Honda get their hybrid batteries from Panasonic EV Energy Co.
http://www.peve.jp/e/shouhin.html , while Ford/Mercury/Mazda get their hybrid batteries from Sanyo. No fuel cells (hydrogen storage) involved - that's a completely different technology and not commercially-available yet.
If you were looking for names of available hybrid vehicles in the US (new or used, 2000 through 2010 model years):
Cadillac Escalade Hybrid
Chevrolet Malibu Hybrid
Chevrolet Silverado Hybrid
Chevrolet Tahoe Hybrid
Chrysler Aspen Hybrid
Dodge Durango Hybrid
Ford Escape Hybrid
Ford Fusion Hybrid
GMC Sierra Hybrid
GMC Yukon Hybrid
Honda Accord Hybrid
Honda Civic Hybrid
Honda Insight
Lexus GS450h
Lexus LS600h
Lexus RX400h/RX450h
Mazda Tribute Hybrid
Mercury Mariner Hybrid
Mercury Milan Hybrid
Nissan Altima Hybrid
Saturn Aura Green Line
Saturn Vue Green Line
Toyota Camry Hybrid
Toyota Highlander Hybrid
Toyota Prius