Understanding Current Direction in Lithium-Ion Batteries
Voltage is NOT a flow—it's an energy difference! Think of it as electrical pressure.
• Discharging: Electrons flow from − to + (powering your device)
• Charging: Electrons are pushed from + to − (storing energy)
• Conventional Current: Always defined opposite to electron flow
The paradox resolved: Both perspectives describe the same phenomenon! Negative charges moving right equals positive charges moving left. It's just a choice of reference frame—both are equally valid!
What actually moves: Electrons (negative particles) physically flow through wires.
Discharging: Electrons flow from anode (−) to cathode (+)
Charging: Electrons flow from cathode (+) to anode (−)
This is the physical reality—electrons are real particles we can measure moving through conductors.
The convention: Benjamin Franklin (1700s) guessed positive charges flow from + to −.
Why we still use it:
• All circuit equations use this convention
• Mathematically equivalent to electron flow
• Changing would cause massive confusion
Direction is always opposite to electron flow, regardless of charging or discharging!
Discharging (Using battery):
Chemical energy → Electrical energy
Electrons flow: Anode (−) → Device → Cathode (+)
Charging (Storing energy):
Electrical energy → Chemical energy
Electrons flow: Charger pushes electrons backward
The process completely reverses! Same components, opposite direction.