We can upgrade your frame to be Di2 Specific making it look like it left the factory as a Di2 frame. We can install a genuine Shimano battery for a Dura Ace 9070 or an Ultegra. Here is some info on what you actually need to get to do the conversion. These batteries are not only lighter and smaller than the original item but they also last longer.
You can see here the battery and the external cable running up the down tube, how much better and cleaner does it look on the right. Note the cable guides have been removed the holes repaired and paint made like new again.
Again looks so clean, the cable entry into the frame looks like it was always ment to be there, that is what we can do make you frame look like it left the factory with intergrated Di2.