My Trustfire flashlight rolled off the kitchen counter and smacked the stone tiled floor. I picked it up, hit the power switch, and nothing happened. Swapped out the cell for a fully charged one and the light came on. Drained that one to the point where it needed to be recharged and charged them both.

The charger indicated green on both cells, but the light only comes on with the one cell.

So can a sudden impact affect a protected Li-ion cell? I guess it can, but is there any way to repair it?