とはいえ:
Although it is said that, even though it is said that, admitting that, that being said, however, nevertheless
「AとはいえB」=「A is the fact, but actually B」
時間がなかったとはいえ、太郎にこれくらいのレポートが書けないはずがない。
(Even admitting that Tarou didn't have much time, I don't believe that he couldn't write a simple report like this).
Same as といっても but:
といっても is for spoken clauses, and
とはいえ is for written clauses