Battery knowledge · Charging and discharging
Discharge
Drawing current from a cell: lithium ions leave the negative electrode, cross the electrolyte and enter the positive one, while electrons do work in the external circuit. The voltage falls as the cell empties.
- Also called
- discharging
Example
Charge balance and state of charge
From 20% SOC, ideal full charge takes 48 min. Integration stops at 100%.
Current is positive into the cell. Constant capacity and 100% charge efficiency; no CC-CV taper.
Explore the graph
SOC rises with accumulated charge; depth of discharge falls by the same amount.
From 20% SOC, ideal full charge takes 48 min. Integration stops at 100%.
SOC = SOC₀ + ∫ I_charge dt / Q; DOD = 1 − SOC
Illustrative model. Current is positive into the cell. Constant capacity and 100% charge efficiency; no CC-CV taper.
Use in Lemonergy
Lemonergy Studio blocks
Controlled discharger worked example
Triggered discharge request with low-voltage/time cutoff, recorded charge and latched completion.
Blocks to use
- Controlled discharger
A trigger starts a discharge-current request. Measured voltage cutoff or maximum active time ends the run and latches completion. Measured discharge current accumulates removed ampere-hours. Disable pauses actuation.
Inputs & settings
- Use the parameter values in the block reference.
- Bundled example verified on the production release of 28 October 2026.
This overview identifies the components to use. Follow the example in Lemonergy for their connections and settings.
- Review the block inputs, units and model limits.
- Open the Studio example and run its bundled model.
- Compare the output channels with the numerical checks; change one input and run again.
Example. Use the defaults below with Measured terminal voltage = 3.8 V, Measured discharge current = 1 A, Start trigger = 1 true / false, Enable = 1 true / false. At 0 s, Discharge-current request is 1 A. Additional checks are listed below.
Observe. Inspect the outputs and numerical checks on the block reference page.
The controller requests current; a separate plant or physical sink performs the discharge. The synthetic example is not a standardized cell test. The example verifies numerical behavior for synthetic parameters. Cell characterization and validation for an intended use are separate tasks.
Open Studio example →Lemonergy Studio blocks
Battery cycle program worked example
Native rest/CC/CV phase sequencer with repeats, voltage interlocks and taper dwell. Commands use discharge-positive current.
Blocks to use
- Battery cycle program
Runs repeated rest, constant-current and constant-voltage phases. Phase duration, voltage conditions and taper dwell control advancement. A voltage interlock stops the program. Charging commands are negative.
Inputs & settings
- Use the parameter values in the block reference.
- Bundled example verified on the production release of 28 October 2026.
This overview identifies the components to use. Follow the example in Lemonergy for their connections and settings.
- Review the block inputs, units and model limits.
- Open the Studio example and run its bundled model.
- Compare the output channels with the numerical checks; change one input and run again.
Example. Use the defaults below with Measured terminal voltage = 3.8 V, Measured signed current = 1 A, Start trigger = 1 true / false, Enable = 1 true / false. At 0 s, Signed current request is 0 A. Additional checks are listed below.
Observe. Inspect the outputs and numerical checks on the block reference page.
The phase program is a signal controller; actuation and measured response come from the connected plant. Synthetic phase settings do not establish a test standard. The example verifies numerical behavior for synthetic parameters. Cell characterization and validation for an intended use are separate tasks.
Open Studio example →References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- Lithium-ion battery fast charging: A review
Anna Tomaszewska et al. · eTransportation · 2019
Topic background · CC-CV and alternative charging protocols, transport limitations, degradation and thermal implications; results depend on cell and test conditions. Software behavior is documented separately in Lemonergy block references.