lemonergy· battery engineering courses

Lemonergy · Design tool

Charge session

Design-tool simulation of a charger connected to the active cell and pack.

Implementation ID
charge-session
Reviewed
2026-10-27

Behavior

At each time step, the session selects the smallest current permitted by charger power, connector current, pack charge acceptance and CV headroom. The tool reports which limit governed charge time, as well as voltage, SOC, current and energy accounting. Its charge current is a positive magnitude.

Interface

Charge session interfaceInputs or arguments on the left, observed outputs on the right. Conserving terminals appear below the component. The tables give units and behavior.Charge sessionDesign 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
Cell
cell		cell recordSupplied by the userSelected library or fitted cell; must be rechargeable with a DCIR value.
Series count
s		countSupplied by the userPositive series count.
Parallel count
p		countSupplied by the userPositive parallel count.
Charger input power
sourceKW		kWSupplied by the userPositive AC-side charger power.
AC to DC efficiency
efficiency		fraction0.93Flat conversion efficiency when no converter curve is supplied.
DC current ceiling
maxDcCurrentA		ASupplied by the userOptional connector/cable ceiling.
Initial SOC
startSoC		fraction0.2Starting state of charge.
Target SOC
targetSoC		fraction1Must exceed the initial SOC.
End current rate
endCRate		1/h0.02Current cutoff used above SOC 0.9.
Time step
dtS		s1Fixed integration step.

Equations and rules

  • V_terminal = OCV(SOC) + I_charge * R
  • I_CV = max(0, (V_max - OCV) / R)
  • dSOC/dt = I_charge / (3600 * Q_Ah)

Worked example

Find the charge-time limit

A 50 kW source at 400 V cannot deliver 50 kW through a 100 A ceiling; that current limit corresponds to 40 kW.

Open Design → Charge session →

Use in a workflow

Find the charge-time limit

The separate Charge session compares power, current, acceptance and CV limits.

  1. Charge session: Runs against the selected cell and pack
    • Source power
    • Connector current
    • Start / target SOC
    • End-of-charge C-rate
Open Design → Charge session

Connected concepts

Limits and interpretation

  • This differs from the Studio network and requires cell resistance data and product access.
  • This is a Design tool, not the Studio regulated-charger block. It uses a different session interface and its own termination rules.

Implementation sources

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

Repository: battery-design · Revision: ef9802329b75bc15bb96885f8ed5d49425106696

  • js/charger.js
  • js/sim1d.js
  • js/power-electronics.js

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