No, it doesn't. BIOS settings are stored in non-volatile EEPROM (or whatever). The battery just keeps the date and time going.
It varies.
Some systems lose their BIOS settings when the battery dies and there is no power,
As
@Dryce says 'it varies '
On all my older builds the motherboards would
lose user changes made in the BIOS settings if the battery was removed. IIRC the one exception was a Gigabyte board that had dual BIOS chips where the BIOS settings could be saved from 'a' to 'b' in the event of a failure.
Note I say user settings changes, the base defaults AFAIK are in non volatile storage. and therefore fixed.
My last build in 2023....the manual (still!) says this:-
"21) BAT (Battery)
The battery provides power to keep the values (such as BIOS configurations, date, and time information) in the CMOS when the computer is turned off. Replace the battery when the battery voltage drops to a low level, or the CMOS values may not be accurate or may be lost.
You may clear the CMOS values by removing the battery:
1. Turn off your computer and unplug the power cord.
2. Gently remove the battery from the battery holder and wait for one minute.
(Or use a metal object like a screwdriver to touch the positive and negative
terminals of the battery holder, making them short for 5 seconds.)
3. Replace the battery.
4. Plug in the power cord and restart your computer.
• Always turn off your computer and unplug the power cord before replacing the battery.
• Replace the battery with an equivalent one. Damage to your devices may occur if the battery is
replaced with an incorrect model.
• Contact the place of purchase or local dealer if you are not able to replace the battery by yourself
or uncertain about the battery model.
• When installing the battery, note the orientation of the positive side (+) and the negative side (-)
of the battery (the positive side should face up).
• Used batteries must be handled in accordance with local environmental regulations."
