battery won't charge past 22% on inspiron xps

It says in the control panel that my battery won't charge past 22% and I know it is right becuase I ran it on the battery and it died in like 15 minutes. I tried to recharge but now it is at 22% again and the battery light is flashing yellow. I let it charge overnight and it is still at 22% and flashing yellow. Can someone please help? I don't even use my battery very often. I have had this laptop exactly one year and I have only used the battery maybe 5 or 6 times. Thanks.