Looks like circuit board got short-circuited because of incorrect current and voltage inputs through the battery charger.
Please keep in mind that every gadget and appliance has different current and voltage needs and these are stated in details on charges or manuals.
While using portable batteries try to use high quality brands such as anker, eassacc, ravpower etc
Most of the times these brands provide Smart tech which detects the input requirements and provides appropriate current. I have reviewed many aka portable chargers here http://www.powerbanktalk.com/best-porta ... view-2015/
and have given detailed specifications.
Let me know if you need further details about power banks