iphone 7 keeps shutting down after 1 minute

It is behaving in a manner that's telling you the battery and device has gotten too hot, so it's shutting down to protect the device and allow it to cool off enough to use it again.

It's trying to keep your device from crashing due to overheating, if so

If it persists, I would call into Apple support and have them run a diagnostic on it to check battery and overall state of your device

Contact - Official Apple Support

Someone on a similar thread says that this has to deal with a date-based issue (Dealing with December 1st), and that many people in Apple Stores are having the same issue.

A temporary fix is to go into "Settings" > "General" > "Date and Time" > change your date to pre-Dec 1st (it's not a fix, but it should prevent your phone from resetting every minute or so)

"[...] it has been escalated to the highest levels and the Apple Store is full of people with the same problem."

"No fi[x] at this time - but we can expect that this will get a lot of attention!"

See the post here:

Re: Phone gets locked every 1 min automatically closing applications

You can also try to reset all as someone suggested

Settings - General - Reset - Reset all settings

Let the device restart

if not resolved, look into your date and time settings or clock app. Make sure it is functioning correctly

Try reset all settings

https://discussions.apple.com/thread/8183164

iOS 11.2 is now available.

Settings > General > Update

I have the same problem with my 5s and my partners 7. "Reset all Settings" did NOT fix the problem. Currently doing a restore from iTunes.

Problem started last night approx 20:00hrs 01/12/2017 AEST

Same problem. Ive Done everything including factory reset and problem persists

Same here, I woke this morning to my phone on the 'enter password' screen. It crashes every 15-20 seconds. Have restarted phone, no difference. Battery drains real fast and the phone gets hot.

Does not happen to my iphone5s, instead it is happening to my iphone6s plus.