battery symbol I've never seen before?

[slime time]

My Alcatel Idol 3 has been having issues for a few months now with plugging in and whatnot
https://forums.androidcentral.com/alcatel-android-phones/867214-my-phone-keeps-shutting-off-when-i-plug.html
this is my earlier post describing what was wrong with it, but recently I've noticed it's been having a harder time charging properly. For the last two days I will get notifications that the battery temperature is too low, then my phone abruptly shuts off.

This morning I was charging my phone (it only charges when its off ) & I tried to check on the progress of it, it displayed a symbol like this on the screen? https://i.gyazo.com/9e4b03c73d82aa0806f3e06f0b3e3b01.png (I couldn't find an actual image of it online, so I drew it)
Is this telling me my battery is dead? I've never seen this thing before

 

[Rukbat]

Probably. The fact that it's getting harder to charge is more of an indication that the battery is bad. (If you regularly let it fall below 40%, that would kill it relatively quickly.)

 

[slime time]

Thank you for the reply! Do you think it would help if I bought a new battery replacement?