iPad shutting down

Your iPad is exhibiting symptoms of a failed/failing battery. You would be best advised to take your iPad along to the Genius Bar at your local Apple Store, or nearest Apple Authorised Service Provider, where the technicians will be able to fully test and assess the condition of your iPad battery. Once tested, appropriate advice or remediation can be offered.

A possible alternative is to directly contact Apple Support- and request a remote battery test. However, of the iPad shuts-down as quickly as indicated, there may not be adequate time to complete the remote test.

Apple Support can be contacted using the Contact Support link at top-right of this page - or you may use the excellent Apple Support App (obviously whilst your iPad is powered using its Power Adapter:

https://apps.apple.com/gb/app/apple-support/id1130498044

Maybe the battery has died.

iPhones have a battery health display but an iPad doesn't.

You may have to take it to an apple authorized repair location to have it examined.