I ordered an extra battery from Amazon the same time I ordered my drone from DJI and got the battery first. I charged it all up but then when I got my drone I realized that Amazon had sent me a damage/cracked battery. I was able to compare it to the one that came with the drone and noticed the differences. The inside flat surface was buckled and it had a hairline crack at the part that overhangs (where the connector is).
The battery box looked brand new and didn't look like it had been opened before.
Amazon swapped it out without any issues. I'm glad that I caught it before I tried to fly with it.