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Lemonergy · Design tool

Charge session thermal node

The optional lumped temperature calculation inside the Charge session tool.

Implementation ID
charge-session-thermal
Reviewed
2026-10-27

Behavior

The session accumulates I-squared-R heat and ambient heat transfer through a substepped lumped thermal node. It uses the selected cell charge-temperature floor and heater setting. The reported temperature belongs to this lumped pack model.

Interface

Charge session thermal node interfaceInputs or arguments on the left, observed outputs on the right. Conserving terminals appear below the component. The tables give units and behavior.Charge session thermal nodeDesign tool
Original Lemonergy interface view. Lines identify ports; they are not a completed simulation circuit.

This reference describes a design tool; its configuration fields are listed below. It has no connected Studio ports.

Parameters

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

Configuration fields
ParameterUnitDefaultMeaning and limits
Ambient temperature
ambientC		deg C25Ambient temperature for the session.
Thermal conductance
uaWK		W/KSupplied by the userOptional pack-to-ambient thermal conductance.
Thermal capacitance
thermalMassJK		J/KSupplied by the userOptional lumped thermal capacitance.
Heater available
hasHeater		booleanFalseWhether the session can heat below the charge floor.

Equations and rules

  • C_th * dT/dt = I_charge^2 * R - UA * (T - T_ambient)

Worked example

Inspect pack temperature

100 kJ/K thermal mass and 100 W/K conductance give a 1000 s no-source temperature-difference time constant.

Open Design → Charge session →

Use in a workflow

Inspect pack temperature

The separate Charge session can include a lumped thermal node.

  1. Charge session thermal node: Balances heat and exchange
    • Ambient temperature
    • Thermal mass (J/K)
    • Conductance (W/K)
    • Heater availability
Open Design → Charge session

Connected concepts

Limits and interpretation

  • One node does not resolve gradients, coolant geometry or runaway. Studio’s native charger instead uses external temperature.
  • A tool-internal temperature node, not a connected Studio thermal block. It does not resolve cell-to-cell or spatial temperature gradients.

Implementation sources

This reference follows Lemonergy implementation sources. Scientific articles support the linked concepts separately.

Repository: battery-design · Revision: ef9802329b75bc15bb96885f8ed5d49425106696

  • js/charger.js

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