How was Perfect Cell created?

The doctor, Dr. Gero created the perfect cell, that is, by absorbing two of his previous creations, which were 17 and 18. The perfect battery is also the one that's the primary antagonist designed to, of course, be complete. The perfect cell is from the future.

He awakens after he is developed. When he awakes, he finds out that the Androids have miraculously been destroyed. The Trunks have destroyed them, come to find out.