Does AppleCare cover worn batteries?

Hi, I have a 2010 MacBook Air with the full AppleCare Protection.

The MacBook is working fine but the battery has started to wear out, this is not a factory defect or anything, it has just worn out over time (and yes, I do understand why and everything.)

Does my AppleCare Protection plan cover this, and if yes, would it cost or would it be fully covered?

Thanks in advace! 🙂