A manufacturer developing grid-scale flow battery systems required a custom stack health monitoring solution to track cell voltages, detect faults, and ensure safe operation. Existing commercial monitoring products included unnecessary features that drove up costs while lacking the flexibility needed for large-scale deployment. The client needed a low-cost, high-accuracy system capable of monitoring hundreds of cells across distributed battery stacks while maintaining measurement precision, reliability over a 20-year operational lifespan, and strict cost targets. The solution required custom embedded hardware and software development capable of real-time data acquisition, self-calibration, fault detection, and seamless integration with the facility’s control systems.
The Details
Industry
Energy & Environment
CAPABILITIES APPLIED
The project presented interconnected technical, cost, and performance challenges requiring custom engineering across hardware, software, and system integration:
Cost Constraints with High Accuracy Requirements: Commercial battery monitoring systems included features not required for flow battery applications, adding unnecessary expense. The client needed a stripped-down, purpose-built solution that achieved high measurement accuracy while targeting a 90% reduction in unit manufacturing cost compared to off-the-shelf alternatives.
High Cell Count Voltage Measurement: Grid-scale flow batteries comprise hundreds of individual cells requiring continuous voltage monitoring. The system needed to accurately measure and aggregate data from large cell arrays while maintaining low per-cell monitoring costs and minimizing wiring complexity.
Precision Analog Design in High-Voltage Environments: Measuring individual cell voltages in high-voltage battery stacks presented signal integrity challenges. The system required low-noise analog circuits with robust high-voltage isolation to prevent measurement errors, electrical interference, and safety hazards.
Self-Calibration and Long-Term Accuracy: Over a 20-year operational lifespan, analog measurement circuits can drift, compromising accuracy. The monitoring system needed automatic self-calibration capabilities to maintain measurement precision without manual intervention or scheduled recalibration procedures.
Fault Detection and Safety Interlocks: The system needed to detect open connections, wire breaks, and abnormal voltage conditions in real time. Safety-critical fault detection required immediate shutdown interlock logic to prevent damage to battery stacks or control systems.
Scalability and Flexible System Architecture: Flow battery installations vary in size and configuration. The monitoring solution needed a modular, distributed architecture that could scale from small pilot systems to large grid-scale deployments without redesigning core components.
Integration with Plant Control Systems: The monitoring system needed seamless communication with higher-level control systems using standard industrial protocols while supporting remote firmware updates, data logging, and diagnostic access without disrupting operations.
Re:Build delivered the Stack Health Monitor (SHM), achieving a 90% reduction in unit manufacturing cost while improving voltage measurement stability and reliability compared to the original commercial system.
The SHM provides continuous real-time monitoring of flow battery cell voltages, full stack voltage, and fault conditions, with data aggregated and reported to the plant controller. A distributed hardware architecture with modular input modules enables scalability across installations of varying sizes.
Embedded software developed in C implements voltage measurement with configurable oversampling, automatic continuous self-calibration, and real-time fault detection. A CAN communication stack manages internal networking, while Modbus-over-TCP provides the facility control system interface. Safety-critical interlock logic enables fault-based system shutdown, and open cell connection detection identifies wire breaks or loose connections.
Power over Ethernet (PoE) integration eliminates separate power wiring. Custom thermoformable enclosures and wiring harnesses were designed for harsh industrial environments.
Internal customer studies confirmed the SHM outperformed the original commercial system, with improved voltage stability and reliability, eliminated operational constraints, and the 90% unit manufacturing cost reduction enabling cost-effective deployment at scale.
