None of the images so far has an ignition barrel and the door handles seems like it has a button on it. Does that mean the key is some sort of proximity sensor card you keep in your wallet like the ones in Mercedes? Does anyone have any details?

 

It's the same "intelligent Key" that's on the Maxima,Altima and Murano. Key fob with rf transmitter and push button start

 

How do you open the door when your battery is dead / changing battery overnight working on the car?

 

There's a real key in the fob (Slides out the end).