Coverage Extension Mode Repetition Scaling and Battery Passivation Voltage Collapse
Passivation voltage collapse in coverage extension mode is prevented by pairing primary cells with hybrid layer capacitors sized for peak frame repetitions.
Closed Circuit Voltage Drop
Meaning
A reduction in the terminal voltage of an electrochemical cell occurs when an external load is connected and current begins to flow through the circuit. This electrical phenomenon, termed closed circuit voltage drop, represents the difference between the open circuit potential of the battery and its active operating voltage. It arises from the combination of internal ohmic resistance, charge transfer polarization, and mass transport limitations within the cell.
Performance Penalty
High discharge currents exacerbate the voltage loss, pulling the available potential closer to the cut-off threshold of the system. This closed circuit voltage drop reduces the operating efficiency of connected electronics by forcing them to draw higher current to maintain the required power levels. When the terminal voltage falls too low, it can trigger premature battery alerts or unexpected shutdowns.
Measurement Protocol
Testing is conducted by applying a calibrated pulse load to the cell terminals under controlled temperature conditions. The system measures the initial stable voltage, applies the test load for a specified duration, and records the active voltage under load. Comparing these two values reveals the operational health of the power source.
System Implication
Hardware designers must account for this decline during high-power events such as radio transmissions. Proper sizing of decoupling capacitors and selection of low-dropout regulators mitigate the effect of transient drops.