Zener diode as temperature sensor
The sensors are not actual &quot;zener diodes&quot;, that's just a simplified way of thinking of the interface.
They are active circuits, that use up to four NTC thermistor sensors and allow the highest of the four temperatures to be read. For this to work there must be a reference and an amplifier for each sensor.
I suspect they are using a 3-terminal voltage reference per sensor for this purpose, and they are simply paralleled so the highest temperature one &quot;wins&quot;. There would also need to be a reference resistor per sensor.  Seems fairly innovative- maybe you should ask our Lithuanian friends if they don't mind you copying it?
Ref:

2.3.5. Energus PS multipoint active temperature sensor Energus PS multipoint active temperature sensor available in the Energus PS Cell
Modules has up to four NTC sensors inside. Innovative analogue signal
OR’ing technique allows all 4 sensor signals to be read with two-wire
acquisition system (one Tiny BMS temperature channel): output acts as
a hot spot detector and reports only the maximum temperature.