Alienware M14 battery part number

Hi from france,

I have a problem with my alienware M14 : the battery is dead (so recycled).

But, when I'm trying to get a new one, impossible to find the spare part number on Alienware or Dell website : no battery = no possible test ;(

Is there anybody to help me to find the part number ?

I can send some more information if necessary (product number or something else ?).

UC : I7-4700 MG

GTX 765M

By the way, how is it possible to know if it is a R&, R2, Rx ???

Regards

(sorry for my poor English, it's not my natural langage ^^)