Lithium-Ion Cell
A cell cross-section showing how ions move through the electrolyte and electrons take the external circuit during charge and discharge.
Lithium-Ion Cell
A cell cross-section showing how ions move through the electrolyte and electrons take the external circuit during charge and discharge.
Inside a lithium-ion cell
Interactive cell cross-section - play charge and discharge to watch ions take the electrolyte and electrons take the external circuit, one of each, every time.
What it shows
Inside a lithium-ion cell, charge moves two ways at once. Lithium ions shuttle through the electrolyte between the negative and positive electrodes, while the matching electrons are forced through the external circuit — one of each, every time. On discharge the cell releases stored energy and state of charge falls; on charge an external source pushes ions back and state of charge rises. Cell voltage tracks the open-circuit curve plus the resistive drop set by C-rate.
Why it matters for BESS
A grid-scale battery is thousands of these cells in series and parallel. Every system-level number — usable energy, round-trip efficiency, C-rate limits, degradation — originates at the cell. Seeing the ion-and-electron split makes the rest of the storage stack (modules, racks, BMS, container) read as scaled-up copies of this one electrochemical loop.
Frequently asked
- How does a lithium-ion cell work?
- During discharge, lithium ions move through the electrolyte from the negative to the positive electrode while electrons flow through the external circuit to power the load. Charging reverses both flows using an external energy source.
- What is the difference between charge and discharge?
- Discharge releases stored energy to a load and lowers state of charge; charge uses an external source to drive ions back into the negative electrode and raises state of charge. Higher C-rate (faster charge/discharge) increases the resistive voltage drop and heat.