Digital Twin — Li-ion Battery Packs

Problem

Practical uses: a battery laboratory can analyse charge/discharge test exports to quantify Ah/Wh and check sampling quality. An electric bus, delivery van or industrial vehicle fleet can inspect exported pack logs for temperature threshold crossings and cell-voltage spread, then choose follow-up tests. A solar-storage site can review charge/discharge energy over a recorded window. Required inputs are timestamped voltage/current; temperature and cell min/max voltages enable additional checks. These are candidate engineering workflows, not demonstrated deployments.

Solution

For early design studies, compare current profiles and pack configurations with a Thevenin 2RC / thermal model and EKF SOC estimation. For imported CSV data, calculate charge/energy and document gaps or threshold crossings. The report helps engineers choose follow-up measurements; it does not identify a failed cell or authorise vehicle return to service. The square, restrained HMI is inspired by ISA-101, without certification claims.

Build path

1. Configure pack topology and compare electrical and thermal scenarios.
2. Inspect overview, cells, trends and simulation controls in Streamlit.
3. Import telemetry, select the current sign convention, and calculate charge and energy.
4. Flag sampling gaps, temperature and cell-voltage spread; export a JSON report with SHA-256 provenance.

Discussion

Validation: 41 Python tests passed. Charge integration was checked on 636 NASA discharge cycles from four laboratory cells (185,721 measurements): mean absolute difference of 0.01303 Ah against capacity labels. This checks numerical consistency, not vehicle qualification or SOC prediction accuracy. SOH requires capacity observations; RUL is a simple trend with at least five observations. No CAN/OBD connection, OEM calibration or universal vehicle diagnosis is claimed.