On the specifications page for the 6000mAh Lipo battery (Polymer Lithium Ion Battery (LiPo) 3.7V 6000mAh | Core Electronics Australia) it indicates the battery includes protection against various risks (“This battery includes built-in protection against over voltage, over current, and minimum voltage (all present under the yellow plastic at the top of the battery).”)
However it indicates the circuitry is under the yellow plastic, whilst this battery has no yellow plastic. Is this a copy and paste error? Does the battery have protection against over voltage, over current and minimum voltage?
Yep, I’d say that’s a copy paste error, though not entirely incorrect. I believe these blue packs are made up of multiple smaller silver packs in the style you’re familiar with, each with their own PCM protected by yellow Kapton tape.
Typically, this is either provided in the datasheet for the battery, or sometimes in the MSDS (Material Safety DataSheet) if it is designed for a particular cell chemistry.
In the case of that 6Ah Li-Ion you’ve linked, these are the specs and schematic for the circuit which is inside the pouch linked at the bottom of my message. The yellow tape that they’ve referred to is likely Kapton tape as James mentioned.
I haven’t opened one up to check (and I wouldn’t recommend doing so, as it is quite dangerous) but I wouldn’t be surprised if the safety circuit’s PCB is attached to the inside of the pouch or the cells using that tape for insulation and rigidity, it’s very common.
In fact, I got a little curious, you can actually see just under the red cable on image from the microscope that Kapton tape inside the top of the cell, and in the other photo you can see the faint outline of the board, it’s mounted inside the pouch:
