Without an exact model number any suggestions would be pure guesswork. A lot depends on the system age as Dell has already indicated that at 1 1/2 - 2 years old the battery may degrade enough to require replacement. Run diagnostics, F12 at boot, and watch for any battery and adapter problems. Also you may find that you will get more replies to your post by reposting in the appropriate laptop forum (this is a desktop forum). And as you see the information which shows personal details or a service tag number has been removed to protect your safety and security.
Hi, Dell Community I am writing to let you know that recently my laptop is in having issue due to battery life. It's unable to store battery and laptop suddenly sleep. I want to know the reason why my laptop is acting like that.    Here you can see details:  . TOS76>  Thank you.
How to Troubleshoot Dell Laptop Battery Issues?