Project 2 Thermal modeling of battery pack
The goal of the project is to use a MATLAB model to identify the charging and discharging rates while simulating thermal impacts, comparing battery life cycles based on performance at various temperatures, and comparing battery life cycles. The library file from the defective lithium battery was used to create the Matlab model shown below.
Simulation Block Diagram
Lithium Cell 1 RC Subsystem
To calculate the total calculation of the battery pack, the Cell Subsystem carries all of the temperature and thermal impacts of the cells.
Lithium Cell 1 RC Systems
Changes in the Parameters are,
Block Parameters for the Cell 01 to 04 are,
Convective Heat Transfer:
This block simulates convection-based heat transfer caused by fluid motion in a thermal network. The temperature difference, heat transfer coefficient, and surface area in contact with the fluid all affect how quickly heat is transferred. This is used for goto blocks and from blocks with 1-4 cells and 6–10 cells. Input is passed from the Goto block to the corresponding From block. Any sort of signal or vector with real or complex values may be used as the input. You can transfer a signal across blocks without actually joining them by using the from and goto blocks.
A signal from a related Goto block is received by the From block, which then outputs it. The output shares the same data type as the input from the Goto block. You can transfer a signal across blocks without actually joining them by using the from and goto blocks.
State of Charge Estimation:
The Coulomb counting method calculates SOC by measuring the battery's discharge current and integrating it over time.This component receives current as an input and outputs the battery's SOC percentage. For soc estimation, a current sensor block is utilised and linked. Using the coulomb counting technique, this ckt calculates the battery SOC percentage. SOC percent is the output, and current is the input. It is assumed that the battery's original SOC is 100 percent (1). An effective way to mimic a battery pack made up of several series-connected cells is demonstrated by an example. The impact on battery performance and cell temperature is also demonstrated by introducing a problem into one of the cells (s).
Cyclic Charge/ Discharge Charge:
AC Current Source
An ideal current source is represented by the AC Current Source block, which keeps a sinusoidal current flowing through it regardless of the voltage applied to its terminals.
The following equation describes the output current:
Temperature Sensor:
A device that detects the temperature difference measured between two sites without generating any heat is what the Temperature Sensor block symbolises as an ideal temperature sensor.
The two sites where the temperature is being monitored are connected via connections A and B, which are thermal saving ports. The temperature difference value is output via Port T, a physical signal port.
From port A to port B is the block's positive direction. T = TA - TB is used to calculate the observed temperature.
This block is a representation of the perfect energy source for a thermal network that can keep the port's absolute temperature constant regardless of the rate of heat transfer. We can set and monitor the ambient temperature using this block.
Peak amplitude
Peak current amplitude. The default value is 1 A
Frequency
Current frequency, specified in Hz or units directly convertible to Hz (where Hz is defined as 1/s). For
example, kHz and MHz are valid units, but rad/s is not. The default value is 60 Hz.
Phase shift
Phase shift in angular units. The default value is 0.
RESULTS:
Using MATLAB, we simulate the thermal impacts and compare life cycle performance at various temperatures, as well as charge and discharge rates, for a 10-cell series lithium-ion battery model.
Conclusion
Normal cells range from 1 to 4. 5 the cell is defective. As we are modelling the effects of temperature on the cell, we supply a cyclic charge/discharge profile to the circuit, which produces the waveform you can see above.It is similar but when the circuit is running on this drive cycle with 5th cell being the fault one.As we present the temperature of results at 300 k, which is 26.85°C, it will show a temperature rise higher than any other cell, and the life cycle of the cell becomes shortened and the cell even can get damaged. The temperature of cells 1-4 and 6–10 is close to 316 k, but in the fifth defective cell, it rises to 330 k, or 56.85 °C. The driving cycle, which is a cyclic charge/discharge cycle, is displayed. For condition 2, we provide a temperature of 310 K, or 36.85°C. The temperature of cells 1-4 and 6–10 is close to 326 K, but the temperature of the fifth faulty cell rises to 340 K, or 66 85°C, and the drive cycle, which is the Cyclic Charge/Discharge drive cycle, is displayed.
Thus, the thermal effect was simulated and compared at various temperatures. Faulty cells experience temperature rise that is more than that of a normal cell charge and discharge cycle, which can harm the cell and impair battery performance.