Li Ion batteries: Difference between revisions
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* Lithium Iron Phosphate (LiFePO4): a nominal voltage of about 3.2V with excellent safety characteristics and long cycle life. | * Lithium Iron Phosphate (LiFePO4): a nominal voltage of about 3.2V with excellent safety characteristics and long cycle life. | ||
Over upper limit (maximum voltage) battery will cause electrolyte breakdown and thermal runaway. | Over the upper limit (maximum voltage) battery will cause electrolyte breakdown and thermal runaway. | ||
Below lower Limit | Below the lower Limit the battery’s chemistry may change irreversibly. | ||
State of charge (SOC) and maximum voltage relation. | State of charge (SOC) and maximum voltage relation. | ||
=== Charging === | |||
The standard charging voltage for most 18650 Li-ion batteries is 4.20 V ± 0.05 V. But slight charge and discharge will improve the battery reliablity and life cycles. | |||
== 21700 cells == | == 21700 cells == | ||
== Spot welding == | == Spot welding == | ||
Revision as of 10:38, 10 August 2025
Introduction
1865 / 18650 cells
Diameter is 18 mm and length 65.0 mm.
Voltage
Note that the chemistry changes and thus these value might be a bit different. Be careful.
- Discharge cutoff voltage (the low voltage limit) is around 2.0V to 2.5V
- Nominal voltage is (usual) 3.6 V or 3.7 V.
- Full charge voltage is 4.2 V, which is the maximum voltage
Chemistry:
- Lithium Cobalt Oxide (LiCoO2): nominal voltage of 3.6V and is known for its high energy density.
- Lithium Manganese Oxide (LiMn2O4): a nominal voltage of 3.7V and offer thermal stability compared to LiCoO2
- Lithium Nickel Manganese Cobalt Oxide (NMC): a nominal voltage of 3.6V or 3.7V and provide a good balance of energy density and power capability.
- Lithium Iron Phosphate (LiFePO4): a nominal voltage of about 3.2V with excellent safety characteristics and long cycle life.
Over the upper limit (maximum voltage) battery will cause electrolyte breakdown and thermal runaway.
Below the lower Limit the battery’s chemistry may change irreversibly.
State of charge (SOC) and maximum voltage relation.
Charging
The standard charging voltage for most 18650 Li-ion batteries is 4.20 V ± 0.05 V. But slight charge and discharge will improve the battery reliablity and life cycles.
