Acid may leak from the battery at the cable connections, resulting in corrosion on the battery cable ends and in the battery tray. A Leaking battery should be replaced and the cables thoroughly cleaned or replaced if necessary.Google+
Car Problem Reports
Chevrolet Impala Corrosion on Battery Cable Ends
Chevrolet Impala Problem
Average Mileage: 56,333 mi (23,333 mi - 120,000 mi)
Visitor, 2009 Chevrolet Impala, 52,000 mi
Excessive corrosion at battery terminals for a car with only 50,000 miles. Battery will need to be changed and this is not an easy process. Very poor placement/design for battery. Have to remove factory braces, fuse assembly and headlight to remove battery. No a quick fix as is usual with battery replacement and not something that would be cheap to fix at repair shop either due to amount of labor needed.
Visitor, 2011 Chevrolet Impala, 23,333 mi
I was told that battery cables had to be replaced as corrosion had backed up into cables. I was told this was not covered under warranty. Cables have been checked at each oil change, no problems until now. I was quoted a price of $622.00 to replace which includes labor. This repair seemed unusual for a car only 3 years old.
Visitor, 2011 Chevrolet Impala, 30,000 mi
This has been going on since I bought the car and I purchase it new. I've been replacing the cable ends over and over and even the battery twice and the problem still exist.