Pump up the juice

These are a pair of batteries, used in power-backup-systems. These systems will give the attached computer(s) enough time to shutdown in case of power-loss and also protect the electronics from power-surges.
Normally these batteries have a flat surface on all sides. This set however had to endure a little power-surge, got warm and expanded a little...

This power-surge was caused by a lightning-strike and it also wrecked a few phones and the PBX. Some other things are acting strange.