BMS SOx Algorithms Engineer

Position description :

The BMS SOx algorithms engineer owns the algorithmic core of the battery management system : he/she must characterise and model cells across the chemistries used in the portfolio (LFP, NMC, LMFP and others), develop the state estimation, SOC, SOH, SOP, SOE, balancing, charging and protection algorithms through MBD and deploy them into the production BMS embedded software with the accuracy, robustness and safety required for the vehicle.

The role is accountable for the estimation accuracy and robustness of the BMS over its life and real usage, as well as for the validation evidence and feedback required from cell and battery lab, vehicle test and field data back into the algorithms.

Accountability : State Estimation Algorithm Development (SOC / SOH / SOP / SOE) :

- Develop and own SOC estimation algorithms : coulomb counting, model-based observers (EKF / UKF / adaptive filters), with robust handling of the flat OCV region typical of LFP.

- Develop and own SOH estimation algorithms : including capacity fade and resistance growth.

- Develop and own SOE : including reset and initialisation strategies after rest and after power-up.

- Develop and own SOP (power management algorithms) : charge and discharge current and power limits as a function of SOC, temperature, voltage limits and ageing.

- Define and drive the required accuracy, convergence and robustness targets for each estimator and prove them against reference data.

Accountability : Cell Characterisation, Modelling and Parameter Identification :

- Define and drive cell test characterization : capacity, OCV, hysteresis, HPPC, rate capability, calendar and cycle ageing, etc. across LFP, NMC, LMFP and other chemistries in use.

- Build and validate equivalent circuit and thermal models of the cell : identify and fit parameters as a function of SOC, temperature, current and ageing state.

- Analyse degradation mechanisms and integrate them into ageing factors modeling.

- Maintain the cell model and parameter library.

Accountability : Model-Based Development and Deployment into BMS Embedded Software :

- Implement algorithms in MATLAB/Simulink and Stateflow to production standards : fixed-point or floating-point designs, execution-time, sampling considerations, memory budgeting, modelling guidelines and interface definition.

- Generate production code (Embedded Coder / TargetLink) and work with the embedded software team to integrate it into the BMS software on the target microcontroller and AFE architecture.

- Verify equivalence between model and target behaviour.

- Resolve numerical, timing, accuracy and resource issues.

- Support measurement and calibration interface definition (A2L, XCP).

- Support on applying ISO 26262 requirements to the algorithm content, including monitoring and verification evidence.

Accountability : Balancing, Charging and Protection Strategies :

- Develop cell balancing strategies (passive / active) including trigger criteria, balancing time budgeting and thermal considerations.

- Develop charging strategies including CC-CV, multi-stage and fast-charging profiles with lithium-plating and temperature-aware limits and coordinate them with the implementations in charger and vehicle.

- Develop protection, plausibility and fault-detection logic : cell imbalance, thermal runaway, early-warning detection, etc.

Accountability : MIL / SIL / HIL Verification and Algorithm Validation :

- Build test schemes and reference data sets and execute MIL and SIL verification against defined accuracy and robustness criteria.

- Set up and use battery HIL / cell-emulators for closed-loop algorithm testing and fault injection of each model/software release.

- Validate algorithms against real cell, module and pack and against real vehicle drive and charge cycles.

- Manage the calibration data set for the BMS algorithms and support pack-level and vehicle-level commissioning.

Accountability : Battery Data Analytics and Cross-functional Support :

- Analyse lab, bench, vehicle and field data to monitor estimation accuracy, degradation trends and anomalies and feed insights back into the algorithms.

- Support warranty, field failure and safety incident investigations with battery data analysis.

- Support cell selection and benchmarking with model-based comparison of candidate cells against the application duty cycle.

- Maintain algorithm documentation, modelling guidelines and lessons learned.

- Support supplier technical reviews on BMS algorithm content.

Skills

Embedded System, MATLAB, Simulink, C, Model Based Development, Battery Management System, ISO, HIL