With the proliferation of IoT, modern meters now enable remote data transmission and cost control functionalities. These meters require long standby times, and typically have very low power consumption, with power spikes occurring only during data upload or control signal reception.
For this power usage scenario, disposable lithium-thionyl chloride (Li-SOCl2) batteries are commonly used. These batteries have a high voltage of 3.6V, a wide operating temperature range of -60°C to +85°C, an extremely low self-discharge rate of less than 2% per year, and a high energy density, allowing for several years of use before needing replacement. These characteristics make Li-SOCl2 batteries particularly suitable for water meters and gas meters.
Cylindrical Li-SOCl2 batteries are categorized into capacity type and power type, with the following parameters:
Energy Type
Power Type
Li-SOCl2 batteries have a high and stable discharge voltage, as shown in the discharge curve below:
Li-SOCl2 Battery Discharge Curve
The graph shows that Li-SOCl2 batteries can suddenly lose power even when the voltage remains high. Therefore, it is not recommended to use voltage to measure the remaining capacity of Li-SOCl2 batteries.
The usual method is to calculate the battery usage time based on the battery capacity and the device’s power consumption, and replace the battery when its expected lifespan is reached.
As mentioned earlier, communication between the meter and the platform requires high power. To balance capacity and instantaneous power, HPC capacitors are typically connected in parallel to increase instantaneous power. Utilizing the high operating voltage and high capacity of Li-SOCl2 batteries, along with the high discharge capability of HPC capacitors, the battery charges the HPC capacitor, which then releases high pulse currents (usually 1-3A).
Terminals with intermittent power consumption use HPC capacitors + lithium sub-energy batteries to maintain normal operation under constant voltage. They are currently the most ideal power supply for high and low temperature environments.
Post time: Jul-12-2024
