pn junction diode working

as we know that whenever any device is connected across the battery , electrons from the -ve electrode flows towards the +ve electrode through the external ckt thereby passing current through the device connected. Now if suppose we connect a pn junction diode across the battery by forward biasing it , then electrons from n side moves towards the p side of the junction and this electrons from the p side reach the +ve electrode thereby completing the ckt . now if we reverse bias the diode , then the potential barrier for the majority carriers will increase but it will act as a downhill for the minority carriers. now everywhere i read i get , that this current gets constant as we increase the reverse voltage and hence called saturation current . But my question is although the carriers contributng to saturation current are thermally generated and limited , but is not the battery supplying any kind of electrons now, if yes , then why the current is so low and constant ... sorry i am lacking concept in this matter , plz explain in detail and in simple terms...

You never connect a forward biased diode across a battery because the current will be unlimited and damage the diode and the battery.
Why are you worrying about the extremely small current of a reverse biased diode that you probably cannot measure?
Forward biased= diode conducts. Reverse biased= diode does not conduct.

Vf = Vth + I* ESR (Vth~0.6 for silicon, 0,2 for Schottky)
Vr= leakage dependent on type, where Silicon tends to have much lower leakage.

as discussed , Reverse current can be quite high in schottky with high rev bias volts