I do a lot of circuit simulation in Proteus, and the main reason is to understand how the circuit works. One of the Proteus libraries I have always wanted is a Li-Ion battery simulation part because Li-Ion batteries are so widely used in circuits these days. However, Proteus does not have an animated part for a rechargeable Li-Ion battery. I wanted a Li-Ion battery that could charge and discharge and show the state of the battery voltage through LED bars. So, I tried to make one, and this is what I wanted to write a note about here.
A rechargeable lithium-ion battery is widely used in portable electronics, IoT devices, embedded systems, and battery-powered projects. In this tutorial, we will simulate a 3.7V rechargeable Li-Ion battery in Proteus and observe how its voltage changes during charging, discharging, and idle conditions.
The simulation demonstrates how the battery can be connected either to a load for discharging or to a power source for charging.
3.7V Li-Ion Battery Simulation
The Proteus circuit uses a 3.7V rechargeable battery, a load resistor, a charging power supply, and a switch that allows us to select between three operating conditions:
- Discharge: The battery supplies current to the load.
- Idle: The battery is disconnected from both the load and charging source.
- Charge: An external power supply charges the battery.
The battery's initial state of charge is set to approximately 20%, allowing us to observe both charging and discharging behavior during the simulation.
Starting the Simulation at 20% Charge
Initially, the switch is placed in the middle position. In this position, the battery is disconnected from both the load and the charging circuit.
When the simulation starts, the battery shows an initial charge level of approximately 20%.
This provides a convenient starting point for demonstrating how the simulated battery responds when a load or charging source is connected.
Discharging the Battery
The switch can now be moved to the discharge position, connecting the 3.7V battery to the load resistor.
Once connected, current flows from the battery through the load. The battery voltage gradually decreases as energy is delivered to the load.
In the simulation, the battery's visual charge indicator also decreases gradually, providing an easy way to observe the change in battery state.
The discharge process is relatively slow because the battery model allows parameters such as the discharge rate to be configured. A more realistic lithium-ion discharge profile can also be incorporated into the model.
As the battery becomes heavily discharged, the voltage and available current become very low. The current does not necessarily become exactly zero immediately; the simulation can take some time to reach the lower limit of the battery model.
Charging the Battery
Next, the switch is moved to the charging position.
This connects the battery to the external power supply. Current now flows into the battery, increasing its stored charge and terminal voltage.
In this particular simulation, the charging process is faster than the previous discharge process. The battery quickly approaches its fully charged condition.
Once the battery reaches the configured full-charge level, the charging current stops.
This demonstrates an important feature of the battery model: the battery does not continue accepting charging current indefinitely after reaching its defined full-charge condition.
Disconnecting the Battery
The switch can then be returned to the middle position.
The battery is now disconnected from both the load and the charging source. No significant current flows through the external circuit.
However, the energy stored in the battery remains available.
This is useful for demonstrating that the battery's charge is retained while it is not connected to a load.
Discharging After Charging
If the switch is moved back to the discharge position, the stored energy is delivered to the load again.
The battery begins discharging from its new, higher state of charge rather than from the original 20% level.
As the simulation continues, the battery voltage gradually decreases, and the charge indicator drops.
Because the battery was previously charged to a higher level, it can continue supplying the load for a longer period before reaching the lower-voltage region.
At very low voltage, the discharge current becomes small, and the battery approaches its fully discharged condition.
Recharging the Battery
The battery can then be connected to the charging source again.
The simulation demonstrates that the battery can be charged, disconnected, discharged, and recharged repeatedly.
This makes the model useful for understanding the basic behavior of a rechargeable lithium-ion battery without requiring physical battery hardware.
What This Proteus Simulation Demonstrates
The simulation provides a simple way to visualize several important battery behaviors:
- Initial battery state of charge
- Battery discharge through a load
- Battery voltage reduction during discharge
- Configurable charging and discharging rates
- Battery charging from an external source
- Full-charge behavior
- Charge retention while disconnected
- Repeated charge/discharge cycles
- Lithium-ion battery discharge-profile modeling
The model can also be modified to experiment with different load resistances, charging voltages, charging rates, discharge rates, and battery profiles.
Download the 3.7V Rechargeable Li-Ion Battery Proteus Model
If you want to experiment with this rechargeable lithium-ion battery model yourself, you can download the Proteus simulation model from the link below.
Li-Ion Battery Proteus Library | Download Free
It can be useful for electronics students, hobbyists, and engineers who want to experiment with rechargeable battery behavior directly inside Proteus before building a physical circuit.
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Conclusion
This Proteus simulation provides a simple visual demonstration of how a 3.7V rechargeable Li-Ion battery behaves during charging, discharging, and idle conditions.
By changing the battery parameters and load conditions, you can further investigate different charging and discharge characteristics and develop more realistic battery models for your Proteus simulations.
