As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PUSH BACK, CREW REPORTED A STRONG ELECTRICAL ODOR IN THE REAR OF THE CABIN. ACFT RETURNED TO GATE. MAINTENANCE TROUBLESHOT AND FOUND EMERGENCY LIGHT BATTERY PACK AT ROW 36CDE SIGNIFICANTLY OVERHEATING. REMOVED AND REPLACED SAME. OPERATION CHECKS GOOD.