Polarium’s Battery Management System has been developed in-house as a core part of the company’s technology and intellectual property. Its design reflects years of experience in deploying batteries into demanding applications, from Tier One telecommunications and public safety networks to rail operators and utility networks. Over the past five years, supplied by Powerbox, Polarium batteries have proven themselves as a safe, reliable, and high-performance energy storage solution across both metropolitan and remote locations where reliability is non-negotiable.
The BMS is not simply a monitoring device. It is an active, multi-layered protection system that continuously supervises every cell and the complete battery pack, ensuring that operation stays within safe limits and that faults are detected and mitigated in real time.
Comprehensive Safety Protections
The BMS provides a range of independent protections, each with defined thresholds and automated responses.
Overvoltage Protection
If an individual cell approaches its upper voltage limit, the BMS engages a patented Current Limiting Device (CLD) to reduce the charging current to a trickle until the safe limit is reached. If the voltage continues to rise, charging is stopped entirely. Monitoring continues so that normal operation can resume once conditions are safe.
Undervoltage Protection
When a cell reaches its low-voltage threshold, the BMS disconnects the load to protect the cell from damage. The Automatic Reconnect Feature allows the battery to remain in standby for up to three months after a low-voltage disconnect without requiring a site visit to reset.
Overcurrent Protection
The CLD responds to excessive charge or discharge currents by reducing current flow without shutting the battery down. On discharge, the battery can deliver bursts up to 6000 W for 60 seconds, with shorter durations allowed as current increases. In the event of a short circuit, the battery disconnects until it detects a charging voltage across the terminals, at which point it resets automatically.
Temperature Protection
Charging current is reduced between 50°C and 55°C (cell temperature) and stopped completely above 55°C. Discharge is prevented above 60°C. At the lower end, discharge is allowed down to -20°C, while charging is limited or blocked below 5°C to safeguard long-term cell health.
Reverse Polarity Protection
The BMS prevents damage caused by incorrect connection of battery terminals.
Intelligent Sensor Network
Temperature and voltage sensors are fitted to every cell, allowing precise detection of abnormal conditions. The system continuously measures cell voltage, current, temperature, time spent at various temperatures, and state of charge. Together, these parameters are critical in determining the State of Health (SoH), which is the available usable capacity and projected lifetime capacity of the battery module.
The BMS also includes g-force detection to identify if a module has been dropped, which could cause latent mechanical or electrical damage. Humidity monitoring provides additional environmental protection. With more than 50 available data points accessible via Modbus, operators can gain a detailed, real-world understanding of battery performance across their deployed fleet.
Redundant Safety Architecture
Polarium’s BMS incorporates redundant safety features, including a watchdog function that ensures independent monitoring systems are cross-checking critical parameters. If one monitoring channel detects an abnormality in voltage, current, or temperature, the system automatically isolates the battery as a precautionary measure. This approach combines electronic and mechanical disconnection through dual devices, an electronic circuit breaker and MOSFETs, for maximum reliability.
This architecture provides an additional layer of assurance in applications where equipment failure could compromise network resilience or public safety. It also aligns with compliance requirements for high-integrity energy storage systems used in telecommunications shelters, control rooms, and other critical infrastructure environments.
Data Transparency and Remote Access
A defining strength of Polarium’s BMS is the level of visibility it offers to operators. Key parameters, alarms, and performance data can be accessed locally via service ports or remotely via the integrated Modbus interface. This allows network operators to view real-time battery health, receive alarms and event notifications, and conduct remote diagnostics without dispatching technicians to site.
The result is a safer, more maintainable energy storage solution that can be managed efficiently across geographically dispersed assets, reducing downtime and operational costs.
In Part 4: Electrical Protection Devices, we will explore the role of integrated breakers, physical protection measures, and alarm capabilities that form the last line of defence against electrical faults.
To learn more about integrating Polarium lithium-ion batteries into your telecommunications or industrial systems with the highest levels of safety and protection, contact Powerbox today to discuss your requirements.
Other useful resources from this series:
Five Layers of Safety in Polarium Lithium-Ion Batteries
Part 1 - Cell Level Safety (Polarium's Five Layers of Safety)
Part 2 - Module Level Safety (Polarium's Five Layers of Safety)
