I understand that the electron flow is from the anode to cathode when discharging a battery but I don't understand why it is reversed for when charging a battery?
closed as unclear what you're asking by pjc50, Enric Blanco, Voltage Spike, Wesley Lee, pipe May 8 '17 at 17:08
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The chemical process in a discharging battery releases the electrons at the cathode, they flow through the load and return at the anode.
To charge the battery, this process (including the chemical reaction) is reversed so the flow of electrons must be reversed since they will then be released from the anode and received (and used in a chemical reaction) at the kathode.
Suppose that the flow of electrons would not reverse, how would discharging then be any different from charging ??
Because you apply little more voltage then the batteries terminal voltage. i.e. 12v battery need around 14.4v This extra 2.2 voltage let the current flows from cathode to anode and reverse chemical reaction(this is called charging).
As simple analogy earth keep forcing you to bottom but while climbing stares you applies little more force to climb.
Hope you get it.