BIOS Backup?

No, it shouldn't affect the BIOS. The user settings in it are stored on the CMOS which has a small battery, most are CR-2032, about the size of a quarter but some Notebooks will have a different arrangement most likely due to limited space in the case/on the motherboard. If the battery is removed only the user-settable features are affected but usually the default/optimum settings will work when next having power and time and date will usually need setting.

Dell Bios backup and restoration
See BIOS recovery from hard drive - Dell
You'll need to check through the listings in that article to see if any of the available methods apply to your computer.

Bios re-setting
If your CMOS battery, rather than the laptop's main battery, is disconnected or gets run down then the Bios will be reset but that is generally not a serious problem as only some [user-customised] settings are involved.
- I work my way through my Bios taking photos of each screen so I have a record of what settings are available and which ones I have altered.

Denis

antares said:

Those instructions I think apply only to Dell Desktops and All in ones, not notebooks.

No, some laptops are included [mine is].

Do also note that there are 3 methods. Under the heading Which Dell computers and tablets support BIOS Recovery? you'll see the general applicability statements for methods 2 & 3

so one of these might apply even though your model is not specifically listed.

Best of luck,
Denis