Exevir

Exevir are a brand of batteries in the Resident Evil universe. Their primary product is what appears to be an SLA (Sealed Lead-Acid) Battery with a long shelf-life.

The SLA Battery has been seen in various locations around the Raccoon City area and likely has a high output because of its size. It has two post-type terminals on the top (positive and negative), and one variation has a non-standard third terminal which has an unknown purpose (potentially for a sensor).

In the games, these batteries are seemingly only used to power elevators such as the Courtyard Elevator in the Spencer Mansion and also the Raccoon City Construction Site Elevator at the Raccoon City Substation.

Although not confirmed, it is most likely that the company provides different forms of energy-related products such as other types of Battery.

Interestingly, in real life the brand ExeVir is the name of a clinical company which researches antibodies to ward off viral infections.

A different kind of Battery also appears in Resident Evil Code: Veronica / X and is of a futuristic design (but it would be safe to assume it is from the same brand) and in the Resident Evil Remake, the Battery is changed once again and has no branding (although it's safe to assume it is again the same brand).

In Resident Evil 7: Biohazard, a different brand named ZzzPower is present.