Gaming DS Lite randomly shuts off

[IC_]

I bought a used DS Lite but it has a few problems... It randomly shuts off if I don't keep it plugged in (even though it says it's fully charged) and when I turn it on after it shut itself off it shows the first time use settings (username, color, date etc.) It keeps settings like the alarm, gba screen, automatic/manual and sometimes it keeps the date and time settings. If I keep it plugged in all the time it will work just fine and play games normally. Any idea what could be causing this and is there any fix for it?

 

[The Real Jdbye]

I bought a used DS Lite but it has a few problems... It randomly shuts off if I don't keep it plugged in (even though it says it's fully charged) and when I turn it on after it shut itself off it shows the first time use settings (username, color, date etc.) It keeps settings like the alarm, gba screen, automatic/manual and sometimes it keeps the date and time settings. If I keep it plugged in all the time it will work just fine and play games normally. Any idea what could be causing this and is there any fix for it?

Bent battery pins causing bad contact with the battery maybe.

 

[IC_]

I noticed something weird, when I push on the battery cover or on the edge of the battery when the cover is removed the DS says that the battery is low and if I push it even stronger it shuts off (if I keep pushing it for a few more seconds after it shuts off it will reset the settings.)
I think that's why my DS is randomly shutting off but what could be the cause of that?