Why does it seem like my car key has something rattling inside like batteries?

Only two keys came with car. 1 with Chrysler emblem on it that goes to trunk and 1 to ignition. Main key has "ilco EH3 on one side other side say " contains replaceable battery " . I am just wondering if it has anything with car not starting???

don't think it suppose to be rattling? i would at least change the battery,or maybe the battery holder clip has broken?