IST Li-ion Battery Simulator V-10.0.1: Module & Pack Design Software for Battery Assembly Companies

A battery assembly company is paid to turn a customer's requirement into a pack that passes AIS-156 or AIS-038, ships on time and does not come back under warranty. Most of the engineering in that job is not cell chemistry. It is integration: choosing a cell and a BMS that suit each other, sizing the series and parallel count, picking fuses, busbars and contactors, deciding whether passive, air or liquid cooling is enough, checking the safety gates, and handing the BMS team a configuration they can flash.

The big simulation suites — Simcenter STAR-CCM+ and Amesim, COMSOL, GT-AutoLion, Ansys Fluent, MATLAB Simscape — are excellent at physics, but they assume a specialist analyst, a large licence budget and a design that already exists. IST Li-ion Battery Simulator V-10.0.1 is built for the step before that: a browser-based, guided tool that takes an application and a parts database and produces a complete pack design and report the same day.

This article explains what the software does for an assembler, shows four real designs run through it, and is candid about where its models stop and where testing or a full CFD tool must take over.

FREE access for IST AEVT Battery course students, Ideal for all application lithium-ion battery pack assembly unit. 

From application targets to a released pack design

The workflow follows the order an assembler's design review already uses. Each step reads the previous one, so the pack is entered once.

1. Define Application. Application type (2W, 3W, 4W, ESS), voltage window, energy, continuous and peak power, charge power, ambient range, IP rating, cooling and the standards in scope.
2. Database. Seven libraries, each importable from .dat files: cells, BMS boards, BTMS parts, module PCBs, busbars, cold plates and other parts (fuses, contactors, connectors, sensors, enclosures). Indian and global suppliers are both covered, so a datasheet becomes a selectable part in minutes.
3. Pack Configuration. Select the cell, then the BMS, then N_s, N_p and modules. The tool builds the cell model, sizes the pack, checks the BMS against the cell, compares the result with the application targets and runs a standards checklist.
4. Thermal Analysis. Conjugate heat transfer, coolant flow, thermal-runaway kinetics and a 3-D air / liquid cooling model of the module.
5. BMS Design. Pack circuit, protection and balancing, SOC/SOH estimation, closed-loop drive cycles on regulatory traces, and generation of BMS C code with SIL test vectors.
6. Circuit Design. HV/LV topology, fuse, busbar, pre-charge and joining-method sizing, module geometry and tolerance stack-up.
7. Safety & Compliance. Capacity, resistance, isolation and abuse gates, plus thermal-runaway propagation, life and warranty prediction, and BMS fault-injection.
8. Reports. One-click report of every stage, and a .pro project file that reopens the whole design.

What it calculates

Every calculation uses the cell, BMS and layout chosen in Pack Configuration, so the numbers in each module stay consistent with each other.

For an assembler, three of these do work that general simulation suites leave to spreadsheets: the cell-to-BMS check, the parts database with supplier part numbers, and the Indian standards checklist.

Result for an assembly company

Weighted for an assembly company's work, IST scores 67/100 against 63 for GT-AutoLion and 54–61 for the other commercial suites. On pure physics fidelity it scores 59/100 against 82–90 for the CFD and electrochemistry leaders.

IST ranks #1 of 9 (67/100). On the day-to-day pack-design work it is the strongest tool here (pack-design fit 78/100): sizing, cell-to-BMS matching, supplier BOM, fuse/busbar/pre-charge, module DFM and the AIS-156 / AIS-038 checklist. It is weak where customers ask for evidence: thermal and runaway physics (fidelity 59/100), ageing that is calibrated but not yet validated on measured data, and overall validation (0.5/5). The practical setup for an assembler is IST for concept, BOM and compliance planning, plus one validated tool for thermal/safety evidence (STAR-CCM+, Fluent or GT-AutoLion) or a test lab, and physical testing at ARAI/ICAT. 

Why each score

• Module / pack electrical sizing (Ns/Np, voltage window, energy, power, resistance). IST: guided Ns/Np sizing against application targets, voltage window from BMS limits, continuous/peak power and heat, all verified by hand for four packs. BatPaC and Simscape Battery (Battery Builder) also size packs; CFD tools need the pack defined elsewhere.
• Cell and BMS selection, compatibility checks. IST checks chemistry, OVP/UVP, series range, current and over-temperature of the chosen BMS against the chosen cell, the daily task of an assembler. No other tool has a BMS-to-cell compatibility check built in.
• Component database & BOM from suppliers. IST: seven importable .dat libraries (cells, BMS, BTMS, M-PCB, busbar, cold plate, other parts) with Indian suppliers. GT-AutoLion ships calibrated cells; BatPaC has material cost tables; the rest hold physics parameters, not purchasable parts.
• HV/LV circuit: fuse, busbar, pre-charge, contactor, joining. IST: catalogue-rounded fuse with temperature derating (capped by BMS limit), busbar cross-section, pre-charge resistor and power, joining-method selection, 2-D busbar magnetostatics. Amesim and Simscape model the full circuit dynamically; COMSOL AC/DC resolves busbar EM in 3-D.
• Module mechanical layout & DFM (dimensions, tolerance stack-up, packing). IST: module footprint from real cell geometry, worst-case tolerance stack-up and packing efficiency. BatPaC computes module and pack dimensions bottom-up. None replaces mechanical CAD.
• Pack thermal design (cooling sizing, temperature spread). IST (upgraded): 3-D voxel CHT of the module with liquid channels or air gaps (Tmax, cell dT, outlet T, pressure drop, pump/fan power) - reduced-order; full CFD still needed for detailed cold-plate design. STAR-CCM+ and Fluent resolve coolant flow and cell temperature spread in 3-D.
• Safety: thermal runaway & propagation. IST (upgraded): module propagation on a 2-D cell network with abuse kinetics, internal short, venting and barrier comparison, AIS-156 5-min proxy - screening before the physical test. AIS-156 Phase 2 propagation evidence is normally a physical test supported by STAR-CCM+, Fluent or GT models.
• Cell behaviour & life / warranty prediction. IST (upgraded): SPMe core (within 2 mV RMS of PyBaMM DFN) plus reduced-order physics ageing (SEI, cracks/LAM, Li plating, knee) calibrated to the datasheet cycle rating - plus a fleet warranty Monte-Carlo (Indian climates, usage spread, fast-charge share) and rate/temperature capability - usable for warranty screening, not yet validated on measured ageing data. GT-AutoLion, COMSOL and PyBaMM model SEI growth and plating.
• Application duty cycle & BMS logic. IST (upgraded): MIDC / MIDC Part-1 / WMTC / WLTC / UDDS and other regulatory cycles with a BMS firmware-logic model (EV and ESS days), fault-injection matrix with DTCs, and generated C code verified bit-for-bit in SIL. Amesim, Simscape and GT-SUITE run standard cycles and BMS control code.
• Standards compliance aid (AIS-156, AIS-038, IS 16893, IEC 62619, UN 38.3). IST is the only tool with an Indian/IEC checklist built in. It is a checklist aid; homologation still needs ARAI / ICAT testing.
• Validation & customer / OEM acceptance of results. OEM customers accept simulation reports from the established tools; IST results have no published validation, so an OEM will not accept them as evidence on their own.
• Licence cost, ease, time-to-design, project & report output. IST: browser wizard, .pro project file and one-click report, low cost; a pack concept takes under an hour. Commercial CFD needs specialist users and costly licences; PyBaMM and BatPaC are free but need Python / Excel skill.

Getting started

A practical way to adopt IST in an assembly company is to make it the front end of every new pack, and keep the specialist tools and the test lab for the evidence stage.

1. Load your approved cells, BMS boards and pack parts into the Database as .dat files, so every design starts from parts you can actually buy.
2. Run each customer enquiry through Define Application and Pack Configuration; the target and BMS checks give a go / no-go in the first meeting.
3. Use the cooling, propagation, life and BMS-logic modules to choose between options before any prototype is built.
4. Hand the generated BMS configuration and SIL vectors to firmware, and the report and .pro file to the customer review.
5. Validate on prototypes, then feed the measured HPPC, ARC and ageing data back into IST so its next prediction is calibrated to your cells.

Used this way, IST can shorten the path from enquiry to a reviewed pack concept to days, while the final word on safety and life stays with testing.