Recharge the battery. If the battery won't hold a sufficient charge, replace it. I assume we are talking about a laptop/notebook computer here. If so, what make/model is it?
That's not the laptop battery, that's the cmos battery on the motherboard. You need to replace it. If you don't know how to do that, we need the exact model of your motherboard or PC to tell you were it's located and what type it is.
Symptoms of a CMOS battery issue are a loss of BIOS/CMOS settings and the clock always needing to be reset.
This could also be a sign of a failing UPS (uninterruptible power supply) battery. Is this system connected to an UPS? If so, switch to the surge suppressor side or a power strip until you replace the UPS battery or the UPS itself.