As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 6129 - IAD - DURING APPROACH MAIN BATTERY NR 2 OVERTEMP. CREW LANDED WITH BATTERY TEMP AT 61 C, IT REACHED 81 C BY THE TIME TO DEPOWER ACFT. CREW EVACUATED PASSENGERS THROUGH MCD PER ARFF DIRECTIONS WITHOUT INCIDENTS. IAS MX REMOVED AND REPLACED NR 2 MAIN BATTERY AND PERFORMED OPERATIONAL CHECK SUCCESSFULLY. ACFT WAS APPROVED TO RETURN TO SERVICE.