MacBook AIr (2017) crashes randomly and only restarts once I plug it in.

Hi orchid_woman,

Welcome to the Apple Support Communities!

We understand you're having some trouble with your Mac. In order to help us to isolate this behavior further, can you provide us some additional details about the experience you're having?

Does your Mac shut down unexpectedly or stop responding?

Does this happen when you're working on anything specific?

Do you see an alert when this happens? If so, what message do you see?

We look forward to your reply.

Cheers!

Is your battery condition 'normal'? Hold the option key and click on the battery icon in the menu bar.

Correct, you need to have Apple replace your battery.