The Item repair recipe from vanilla Minecraft works also IC² Items that use electricity. This means you can "repair" e.g. two partially depletet Diamond Drill into one full Diamond Drill, effectively wasting the second Drill. This does also work for other things, like Energy Crystals. While this is a nice feature for "regular" tools, i think this is not intended for Tools that relay on electricity. Maybe it is just not diasabled jet.
There is also a bug with the recipe for the CF-Pack. You can only craft it, using CF-Sprayers that do not have a visible damage-bar, like when they are taken from the Creative inventory.
It is also possible to fill CF-Sprayers without using CF-Pellets by just "repairing" them.