If there aren't any carriage return "¶" characters in your repeating field, and if all repetitions are filled and non-container, you could do it by creating a calc field "Joined" defined as:
Joined = Substitute ( List ( RepeatingField ) ; ¶ ; "|" )
That is, the "Joined" field would connect all repetitions with a known separator such as "|"
And then export this field...
remember that List() will get non-blank values, so if the repeating field has
List will be:
... and that may be sufficient (or not).
I don't know if Excel can post-process the Group Separator (ASCII 27). There may be other ways to export, but it would depend on what is acceptable to bigtom (to List or not to List).
I liked export as html, then Excel can open it as repeated fields into individual cells.