What is this thing inside layer the Galaxy S5 battery⁉️

[electronium]

greeting and good time to the colleagues of the forum
The issue is that I found the battery of a mobile phone named Galaxy S5 model sm-g900h and it had a problem and I wanted to see that it was not charging. I took off the layer of the battery and noticed something that I don't know what it is and what it does in the battery.

 

[carbonzit]

Well, I don't know either. What does it look like? Picture? or at least a description would help.

 

[rjenkinsgb]

Most "pouch" cells have a protection module in them, to prevent overcharge or over-discharge.
Some for phones etc. may have a more complex module with the current monitoring for charge state as well.

It's usually across the terminal end of the cell. It may be visible, depending if the protective wrap is see-through or opaque.

Examples - a couple of generic pouch cells with the module visible, and a scrap battery from an iphone with the black covering removed.

 

[electronium]

I sent the photo, it seems that it was not uploaded, but now it has been sent

 

[carbonzit]

Gotcha; came through.
It sure looks like an RFID patch, but why?

 

[Nigel Goodwin]

Is it a wireless charging coil?.

 

[rjenkinsgb]

OK, now the photos have been added.

It's a charging coil for the QI system or similar.