Understand the retained battery parameter row
A two-RC equivalent circuit separates a cell's immediate resistive voltage drop from two slower polarization responses. Lemonergy uses one retained parameter row to demonstrate the forward pulse response and a separate parameter recovery experiment.
The attributed source is MathWorks, Estimate Battery Model Parameters from HPPC Data. The CT-01 contract transcribes ParameterSummary ID 5, identified as BAK N18650CL-29 at 25 °C and SOC 0.4 during discharge. These are fitted model parameters for that operating point, not a manufacturer datasheet or a set of operating limits.
Published values retained in the contract
Each S1 link leads to the campaign's downloadable reference contract. The hppc.operatingPoint and hppc.publishedSolution fields identify the exact values and their source. “Selected row” below means the stated temperature, SOC and discharge direction.
| Quantity | Symbol | Value | Unit | Conditions and use | Basis |
|---|---|---|---|---|---|
| Cell capacity | Cnom | 2.84 | Ah | Retained characterization metadata; not an evolving forward-model state | Retained context · S1 |
| Temperature | T | 25 | °C | Selected parameter row; held fixed | Retained operating point · S1 |
| State of charge | SOC | 0.4 | 1 (fraction) | Manually assigned source operating point; held fixed in the model | Retained operating point · S1 |
| Open-circuit voltage | OCV | 3.7353 | V | Selected row; held fixed during recovery | Rounded published value · S1 |
| Ohmic resistance | R0 | 0.040839 | Ω | Selected row; fitted in the recovery experiment | Rounded published value · S1 |
| Fast-branch resistance | R1 | 0.0020343 | Ω | Selected row; fitted in the recovery experiment | Rounded published value · S1 |
| Fast-branch time constant | τ1 | 1.1318 | s | Selected row; fitted in the recovery experiment | Rounded published value · S1 |
| Fast-branch capacitance | C1 | 556.35 | F | Published rounded comparison value; forward blocks use R1 and τ1 | Rounded published value · S1 |
| Slow-branch resistance | R2 | 0.012923 | Ω | Selected row; held fixed during recovery | Rounded published value · S1 |
| Slow-branch time constant | τ2 | 20.73 | s | Selected row; held fixed during recovery | Rounded published value · S1 |
| Slow-branch capacitance | C2 | 1604.2 | F | Published rounded comparison value; forward blocks use R2 and τ2 | Rounded published value · S1 |
| Source discharge current | Isource | −6.1871 | A | Source convention uses negative discharge | Retained observable · S1 |
| Source pulse duration | tpulse | 30 | s | One disclosed discharge pulse | Retained observable · S1 |
Capacitance and time constant are related by Ck = τk/Rk. Independently rounded table entries need not satisfy that relation exactly at every printed digit. The retained source does not provide parameter confidence intervals; extra digits in a calculated response do not establish extra physical certainty.
How Lemonergy constructs the example
Lemonergy changes the current convention to positive discharge and evaluates V = OCV − I R0 − v1 − v2. Each polarization state follows dvk/dt = (I Rk − vk)/τk. The voltage waveform is constructed from these equations; the measured source voltage trace was not imported.
| Quantity | Symbol | Value | Unit | Conditions and use | Basis |
|---|---|---|---|---|---|
| Example discharge current | I | +6.1871 | A | Same pulse magnitude, positive-discharge convention | Sign transformation · S1 |
| Initial polarization | v1(0), v2(0) | 0 | V | Both branches begin relaxed | Authored initial state · S1 |
| Recovery sample interval | Δt | 0.1 | s | Uniform end-of-step samples in the fitting benchmark; not a source acquisition rate | Authored sampling · S1 |
| Recovery holdout current | Iholdout | 5 | A | Generated from the same fixed linear model; not another measured experiment | Authored holdout · S1 |
The authored sequence is 10 s rest, 30 s pulse, 70 s rest, another 30 s pulse and 70 s rest. The forward example keeps the parameter row fixed; the recovery benchmark estimates only R0, R1 and τ1. Neither workflow reconstructs a measured HPPC test across changing SOC and temperature.
The source's recorded minimum of 3.4001 V is not a comparison target because its measured trace is absent. Its FitPc result is also not treated as Lemonergy RMSE. The contract's simulator-support fields, such as cell mass and voltage or temperature windows, are not source-backed cell specifications and should not be copied into a datasheet table.
Publication date and retained provenance
The publication date is unknown. The original contract records retrieval on 23 August 2026; campaign notes record a subsequent source check on 30 September 2026. The wiki's record-review date describes local editorial work, not a fresh visit to the original documentation.
No complete source-page copy is retained. The external application was not executed for this comparison. Because documentation URLs can change, reproduce the frozen contract rather than assuming the current webpage contains identical values. Use the linked Lemonergy tutorials for the model pictures, run instructions and interpretation of numerical agreement.