It is highly unlikely, the BIOS is the firmware on your PC, it is rare to become corrupt unless you touch things yourself entering the PC to boot, and from there you enter the settings to change things. What is not close me why you left the battery with the PC turned on in the BIOS screen is downloaded. Is that bad or you expressed you ?. In any case not affected in the slightest, it's that way a battery will discharge slower, and honestly I see no reason to download a battery leaving the PC in the BIOS screen, but ...
There is, as far as I know, software that makes you check the BIOS, only specific programs and manufacturers to update.
So just go with which key corresponds to your computer and load the default values, if the BIOS does and restart with no problem, everything is fine.