I doubt very much that the CMOS battery is of the Lithium type. If you have the battery type number or can remove it briefly to read its label, I suspect you will find it is Alkaline. BUT removing the battery might reset your BIOS, so maybe don't do that unless you must. You might be able to read the label text on it without removing - need a good light and maybe a magnifying glass.
If you have to remove that battery, first you should make a note of all the custom settings you have made in BIOS Setup so you can restore them after a reset.