Battery knowledge · Charging and discharging
Constant voltage
A charge stage in which the terminal voltage is held at a selected limit while the current is allowed to fall. The charge added during this stage and its duration depend on the cell, initial state, voltage limit and termination current. [1]
- Abbreviation
- CV
Example
Read the taper correctly
In a hypothetical CV stage with a 4.0 V ceiling, the controller holds terminal voltage at that ceiling while current tapers as the cell state changes and its OCV rises. A voltage plateau does not mean the charge session has completed; the current cutoff and dwell still matter.
Explore the graph
See which quantity is held constant, when the phase changes and how charging ends.
Voltage holds at an illustrative 4.15 V while current tapers. Real controllers must limit initial current and define termination.
CC: I = I_set · CV: V = V_limit
Illustrative model. Positive current charges the cell. Time is normalized; selected thresholds are not cell-specific recommendations. The voltage trace ends at termination; post-stop relaxation is excluded.
Use in Lemonergy
Lemonergy Studio blocks
Build CC–CV charging
Native current and voltage regulation act against an explicit battery.
Blocks to use
- Charging schedule and target policy
Permits charging
Inputs & settings
- strategy
- targetSoc
- departureS
- soc, available, chargerDone → permit
- Regulated CC/CV charger
Regulates current and voltage
Inputs & settings
- currentA
- voltageV
- cutoffCurrentA / cutoffHoldS
- Electrical ports p and n
- Battery with SOC-dependent OCV
Stores charge and supplies terminal voltage
Inputs & settings
- capacityAh
- initialSoc
- emptyVoltageV / fullVoltageV
- resistanceOhm
- Electrical ports p and n
- Electrical reference
Sets zero potential
Inputs & settings
- Connect p to reference net
This overview identifies the components to use. Follow the example in Lemonergy for their connections and settings.
Example. An illustrative 100 Ah battery with a 420 V ceiling can use a 32 A cap. At the ceiling, current falls as OCV rises.
Observe. Completion needs current below cutoff at the CV ceiling for the configured dwell. Site-limited low current is different.
The battery uses linear OCV and fixed resistance. It does not automatically add aging, thermal dynamics or balancing.
Open the Studio example →References & further reading
Technical references
- Lithium-ion battery fast charging: A review
Anna Tomaszewska et al. · eTransportation · 2019
Technical reference · 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.