Estimating SoC and SoH of Li-ion Battery Using Coulomb Counting Method in IoT Node Application

In this research, monitoring of the battery pack is calculated by using the Coulomb Counting (CC) method based on the Internet of Things (IoT) by the state of charge (SoC) parameter as an indicator of battery capacity and state of health (SoH) as lifespan which represents the ability of the battery to store and deliver energy. SoC is the ratio of the remaining energy to the maximum energy capacity of the battery which is usually expressed as a percentage from 0% to 100%. Common terminologies used to represent battery capacity are nominal capacity—according to the datasheet—and typical capacity—calculated based on real-world conditions—using the INA219 sensor to read current (I) and voltage (V). The system designed and integrated with a 3S Battery Management System (BMS) can operate for ±22.964 hours with a SoC of ±78.85% at a voltage of 8.83V, based on a current load of ±89.28mA, and with a coulomb efficiency of 0.99. The battery monitoring system can prevent over-discharge and limit the Deep of Discharge (DoD) at ±20.15% with a C-Rate of 0.034C based on the current load. The voltage drops gradually which is relatively stable between 12V to 10V. However, there is a significant voltage drop when the battery pack voltage is below 10V and goes until the end of time. From this DoD value, it will produce more than ±10000 life-cycles of battery SoH Value which determines the life of the battery cells. Even when it reaches ±4500 cycles the energy that can be maintained is still ±75% of its maximum capacity. The SoC and SoH parameters obtained can be used as a reference for replacing the battery before it causes malfunctions in the Node devices in the IoT system being built.