Ok, I must set up this tread:
I) Thank you all
II) These aren't diodes, they looks like diodes but they are...TRANSIENT VOLTAGE SUPPRESSOR.
In particular, EKP is like an open circuit if voltage is below 18.8V, it could begin to work at 20.9V, but
only if voltage applied is 23.1V or more it start to clamp voltage at its maximum designed value: 30.6V.
So if dude try to jump start a 12V vehicle with 24V battery the TransVoltSuppr will (probably) save this board.
You could till the field with a lot of TransVoltSuppr, then comes the super dude: it will reverse battery cables
+ with -, - with +, this means negative voltage = negative current, wrong current direction instantly kills mosfet, TransVoltSuppr are placed near the mosfets, mosfets explodes, TransVoltSuppr shorted.
Board with serious damage, car with no more door lock, no electric windows or automatic roof and dude in panic, with jump cables still in his hands.
Fortunately, engine ECU is designed to survive to reverse polarity, so super dude could drive home with
his half broken car instead of remain blocked in the desert.