lemonergy· battery engineering courses

Lemonergy · Studio block

Passive cell balancer

Hysteresis selects high cells and reports bleed current and resistor heat.

Implementation ID
battery-passive-balancer
Reviewed
2026-10-27

Behavior

Selects cells above the lowest cell voltage using separate turn-on and turn-off differences. Enabled channels report bleed current and resistor heat; the signal block itself does not impose the electrical current.

Interface

Passive cell balancer interfaceInputs or arguments on the left, observed outputs on the right. Conserving terminals appear below the component. The tables give units and behavior.Passive cell balancerStudio blockvoltageenableactivecurrentheat
Original Lemonergy interface view. Lines identify ports; they are not a completed simulation circuit.
Ports and observed outputs
NameDirectionUnitMeaning
voltageinputVCell voltages; 3 channels at the default configuration.
enableinputtrue / falseEnable; scalar.
activeoutputtrue / falseBleed switches; 3 channels at the default configuration.
currentoutputABleed currents; 3 channels at the default configuration.
heatoutputWBleed power; 3 channels at the default configuration.

Parameters

Defaults are initial model values. Select values for your own model and operating conditions.

Configuration fields
ParameterUnitDefaultMeaning and limits
Sample interval (s)
sampleTimeS		s1Positive sample interval. Initialization has zero elapsed time; subsequent accepted samples update memory.
Number of measurement channels
cells		13Number of measurement channels. This is an editable model input; the default belongs to the synthetic worked example.
Turn-on voltage difference (V)
onDeltaV		V0.02Turn-on voltage difference (V). This is an editable model input; the default belongs to the synthetic worked example.
Turn-off voltage difference (V)
offDeltaV		V0.01Turn-off voltage difference (V). This is an editable model input; the default belongs to the synthetic worked example.
Bleed resistor (Ω)
resistanceOhm		Ω40Bleed resistor (Ω). This is an editable model input; the default belongs to the synthetic worked example.
Minimum voltage (V)
minVoltageV		V3Minimum voltage (V). This is an editable model input; the default belongs to the synthetic worked example.

Equations and rules

  • Ibleed[j] = selected[j] * voltage[j] / resistance
  • Pbleed[j] = voltage[j] * Ibleed[j]

Worked example

Passive cell balancer worked example

Use the defaults below with Cell voltages = [3.95, 4, 3.96] V, Enable = 1 true / false. At 0 s, Bleed switches is [0, 1, 0] true / false. Additional checks are listed below.

Open Studio example after release →
Numerical checks for the bundled synthetic example
OutputTime (s)Expected valueUnitAbsolute tolerance
Bleed switches
active		0[false, true, false]true / false1e-08
Bleed currents
current		0[0, 0.1, 0]A1e-08
Bleed power
heat		0[0, 0.4, 0]W1e-08

Explore the recorded outputs

Passive cell balancer recorded example

Passive cell balancer / Bleed currents [1]
Passive cell balancer / Bleed currents [1] against timeRecorded synthetic simulation values. Time in seconds; output in A.-0.50-0.250.2500.50.250.750.51ATime (s)
Passive cell balancer / Bleed currents [1]: 0 A at 0 s

2 actual recorded samples. Lines are visual guides between samples. Synthetic example, not measured cell data.

Download the recorded samples (JSON) · Open this Studio example after release

Use in a workflow

Passive cell balancer worked example

Hysteresis selects high cells and reports bleed current and resistor heat.

  1. Passive cell balancer: Selects cells above the lowest cell voltage using separate turn-on and turn-off differences. Enabled channels report bleed current and resistor heat; the signal block itself does not impose the electrical current.
    • Use the parameter values in the block reference.
    • Implementation tested locally; public release pending.
Open Studio example after release

Connected concepts

Limits and interpretation

  • Connect the request to a physical balancing interface to load a conserving network. The synthetic resistor is not a hardware rating.
  • The example verifies numerical behavior for synthetic parameters. Cell characterization and validation for an intended use are separate tasks.

Scientific and mathematical references

These sources explain the scientific and mathematical background. The behavior, interface and limits above define the Lemonergy implementation; a citation does not imply every model option in the source is implemented.

  1. Getting Started with the BQ76925

    Texas Instruments · 2019

    Technical reference · A concrete BMS analog front-end example: cell voltage, current, temperature measurement and MCU integration.

Implementation sources

This reference follows the public interface and locally verified numerical checks for an upcoming release.

Contract: Lemonergy Studio public contract · Verification record: verification-2026-10-27

  • docs/glossary/native-block-verification.json

This implementation and its workflow uses (JSON) · Knowledge graph (JSON-LD)