This has happened a couple of times the during the last year. This is what happens:

Battery 100% charged with charger plugged in.

Closing lid.

Unplugging charger and taking the laptop to an other place.

Starting computer and get the message battery critically low and the computer shuts down.

Last time the battery was empty and after fetching the charger it started to charge ( se image ).

An other time the battery went from 1% to 97% in a few minutes after plugging in the charger.

What is happening. Is the battery or the charger circuit defect. What can I do. Battery seems to have lost capacity from 94 Wh to 67 Wh.