Feature: Energy storage
A range of CEI batteries Current draw must also remain within specified limits. A
datasheet might specify that a cell be charged at a particular current level while allowing higher discharge currents during operation. Temperature management is equally critical, because exceeding safe temperature thresholds can degrade the cell or trigger thermal events. Considering these constraints, lithium batteries require careful
monitoring and protection systems to maintain safe operation. Tis is where power management becomes essential. Engineers must design systems capable of continuously
monitoring battery conditions while regulating voltage, current and temperature throughout the life of the pack. Without these safeguards, the advantages of lithium-based energy storage would be difficult to harness safely.
Battery management system fundamentals At the centre of modern battery power management is the battery management system (BMS). Tis electronic control architecture monitors individual battery cells, enforces safe operating limits and ensures balanced performance across the pack. In many applications, multiple cells are connected in a series
to achieve higher system voltages. For instance, a battery pack designed to deliver approximately 24V might be constructed from several cells that are connected positive to negative in sequence. Since individual lithium cells typically output around 3.6-3.7V nominally, multiple cells must be combined to reach the required system voltage. Within such series configurations, each cell must be monitored individually. Small differences in capacity or internal resistance can cause cells to driſt apart in voltage over time. If leſt
unmanaged, these imbalances can reduce system efficiency or push certain cells outside safe operating limits. To prevent this, the BMS continuously monitors the state of each cell.
Analogue front end monitoring A key component of many BMS architectures is the analogue front end (AFE) IC. Te AFE measures the voltage of each individual cell or group of cells within the battery pack, and oſten manages transistor gates used during balancing operations. It typically communicates measurement data to a microcontroller via an inter-integrated circuit (I²C) interface, allowing the microcontroller to assess and determine how the system should respond. Tis could be that balancing is required, charging should stop, or a fault condition has occurred. Many AFEs also include inputs for temperature sensors and
current sensing, along with a dedicated alert signal that can interrupt the microcontroller when a fault condition is detected. Tis ensures that safety-related events are handled immediately.
Supporting control electronics Additional components are oſten included within a BMS to expand functionality and improve safety. For instance, a secondary protection IC might provide redundant monitoring in case the primary control system fails to respond to a fault condition. If abnormal behaviour persists, the secondary system can disconnect the battery pack by triggering a fuse or other cutoff mechanism. Many battery packs also include a fuel-gauge IC, which estimates the battery’s state of charge. Because battery voltage
www.electronicsworld.co.uk May 2026 39
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