Absolutely do not start ripping apart your old laptop battery to replace cells if you don’t know what you’re doing. Depending on the battery size and type, you might also not have many cells at all to replace.
You would be better off buying a cheap replacement battery, especially if it’s already 10 years old. Any cells that aren’t bad today will likely be very soon.
Telling people to pop open a Li-Ion battery is asking for a fire.