i have exactly the same issue since about 3 weeks. The problem seems to be correlated with the desktop windows manager called dwm.exe which have also about 2% cpu time. I don't have a real solution but i figured out two workarounds to work with matlab without high cpu usage and the following battery leak:
#1 start matlab out of the command line from windows with: matlab -softwareopengl
But on my machine i do not have any graphic smoothing anymore.
#2 switch to a windows basic design with high contrast and than start matlab normally
The basic design do not need dwm.exe and the cpu goes back to normal 0-1%. After matlab startup you should be able to return the previous design without troubles (at least on my machine).
Hope this helps temporary but is long-dated not satisfactorily.