I think what you are looking to do can be accomplished by doing the following...

given your example, the line you write outto the csv file via filehandle should be something like:

qq["Cell 1","Cell 2","Cell 3\nCell 4\n\nCell 5","Cell 6","Cel 7"\n];

the trick is to encapsulate the new line (\n) within the double quotes.

This works for me, YMMV, HTH!