Meaning
Electrical capacity metrics estimate the operating duration of a non-rechargeable energy source in a wireless device under specific load conditions. The calculation of primary lithium battery service life depends on the self-discharge rate of the cell and the duty cycle of the connected radio transceiver. This estimation determines the maintenance schedule and replacement frequency of remote sensors in industrial deployments.
It does not apply to rechargeable chemistries which have different degradation and cycle characteristics.
Discharge Behavior
Active transmissions draw high pulses of current that can cause transient voltage drops in the cell. The internal resistance of the battery rises as the active material is consumed. This increase can trigger premature low-voltage shutdown in the host system.
Environmental Impact
Extreme temperature variations affect both the chemical reaction rate and the self-discharge rate of the battery. High temperatures accelerate the self-discharge process and reduce the total available capacity of the cell. Low temperatures increase the internal resistance of the battery.
Design Optimization
Circuit designers use low-power sleep modes and efficient antenna designs to minimize the energy consumed per transmission cycle. This optimization extends the operating duration of the system without requiring a larger cell. It represents a fundamental trade off in wireless sensor design.
