Project 2 Thermal modeling of battery pack
For a 10 cell series lithium ion battery model, simulate the thermal effects and compare life cycle performance at various temperatures, charge & discharge rates using MATLAB.
To analyze temperature and life cycle parameters of the 10 cell series battery pack.
- Connect 10 cells in series analyze the response to a cyclic discharge source.
- Change the ambient temperatures of the battery pack and compare the performances.
- Add the fading parameters of the battery and analyse the performance after each discharge cycles.
Simulink Modelling of Battery pack
This Battery pack modelling in used many blocks
1.Battery (Table-Based)
The Battery modeling procedure followed in the MATLAB is explained below. The MATLAB model is available from the library given below.
Battery (Table-Based)
Library:
Simscape / Electrical / Sources
Description
The Battery (Table-Based) block represents a high-fidelity battery model. The block calculates no-load voltage as a function of charge level and optional temperature using lookup tables and includes several modeling options:
-
Self-discharge
-
Battery fade
-
Charge dynamics
-
Calendar aging
The Battery (Table-Based) block has four modeling variants, accessible by right-clicking the block in your block diagram and then selecting the appropriate option from the context menu, under Simscape > Block choices:
- Uninstrumented | No thermal port — Basic model that does not output battery charge level and simulates at a fixed temperature. This modeling variant is the default.
- Uninstrumented | Show thermal port — Model with exposed thermal port. This model does not output internal charge level of the battery.
- Instrumented | No thermal port — Model with exposed charge output port. This model uses a fixed temperature throughout the simulation.
- Instrumented | Show thermal port — Model that lets you output internal charge level of the battery. Both the thermal port and the charge output port are exposed.
The instrumented variants have an extra physical signal port that outputs the internal state of charge. Use this functionality to change load behavior as a function of state of charge, without the complexity of building a charge state estimator.
All the cell parameters depend upon Temperature and SOC and the values of them are given below.
2.Voltage Sensor
- Library:
-
Simscape / Foundation Library / Electrical / Electrical Sensors
Simscape / Electrical / Sensors & Transducers
Description
The Voltage Sensor block represents an ideal voltage sensor, that is, a device that converts voltage measured between two points of an electrical circuit into a physical signal proportional to the voltage.
Use the + and - ports to connect the sensor in parallel with the block (or several blocks) where you want to measure the voltage. Port V outputs the measurement result as a physical signal. Use a PS-Simulink Converter block to connect this port to Simulink® blocks, such as Scope or Display.
3.Current Sensor
- Library:
-
Simscape / Foundation Library / Electrical / Electrical Sensors
Simscape / Electrical / Sensors & Transducers
Description
The Current Sensor block represents an ideal current sensor, that is, a device that converts current measured in any electrical branch into a physical signal proportional to the current.
Use the + and - ports to connect the sensor in series with the other blocks in the branch where you want to measure the current. Port I outputs the measurement result as a physical signal. Use a PS-Simulink Converter block to connect this port to Simulink® blocks, such as Scope or Display.
4.Controlled Current Source
- Library:
- Electrical Sources
Description
The Controlled Current Source block represents an ideal current source that is powerful enough to maintain the specified current through it regardless of the voltage across the source.
The output current is I = Is, where Is is the numerical value presented at the physical signal port.
The positive direction of the current flow is indicated by the arrow.
5.PS Constant
- Library:
-
Simscape / Foundation Library / Physical Signals / Sources
Description
The PS Constant block generates a physical signal of a constant value. You specify the value and unit of the signal as the Constant parameter.
6.Integrator
- Library:
-
Simulink / Commonly Used Blocks
Simulink / Continuous
Description
The Integrator block outputs the value of the integral of its input signal with respect to time.
Simulink® treats the Integrator block as a dynamic system with one state. The block dynamics are given by:
{˙x(t)y(t)=u(t)=x(t) x(t0)=x0
where:
-
u is the block input.
-
y is the block output.
-
x is the block state.
-
x0 is the initial condition of x.
While these equations define an exact relationship in continuous time, Simulink uses numerical approximation methods to evaluate them with finite precision. Simulink can use several different numerical integration methods to compute the output of the block, each with advantages in particular applications. Use the Solver pane of the Configuration Parameters dialog box (see Solver Pane) to select the technique best suited to your application.
7.Gain
- Library:
-
Simulink / Commonly Used Blocks
Simulink / Math Operations
HDL Coder / Commonly Used Blocks
HDL Coder / HDL Floating Point Operations
HDL Coder / Math Operations
Description
The Gain block multiplies the input by a constant value (gain). The input and the gain can each be a scalar, vector, or matrix.
You specify the value of gain in the Gain parameter. The Multiplication parameter lets you specify element-wise or matrix multiplication. For matrix multiplication, this parameter also lets you indicate the order of the multiplicands.
Gain is converted from doubles to the data type specified in the block mask offline using round-to-nearest and saturation. The input and gain are then multiplied, and the result is converted to the output data type using the specified rounding and overflow modes.
8.Add, Subtract, Sum of Elements, Sum
- Library:
-
Simulink / Math Operations
HDL Coder / HDL Floating Point Operations
HDL Coder / Math Operations
Description
The Sum block performs addition or subtraction on its inputs. The Add, Subtract, Sum of Elements, and Sum blocks are identical blocks. This block can add or subtract scalar, vector, or matrix inputs. It can also collapse the elements of a signal and perform a summation.
You specify the operations of the block with the List of signs parameter with plus (+), minus (-), and spacer (|).
-
The number of
+and-characters equals the number of inputs. For example,+-+requires three inputs. The block subtracts the second (middle) input from the first (top) input, and then adds the third (bottom) input. -
A spacer character creates extra space between ports on the block icon.
-
If performing only addition, you can use a numerical value equal to the number of inputs.
-
If only there is only one input port, a single
+or-adds or subtracts the elements over all dimensions or in the specified dimension.
The Sum block first converts the input data type to its accumulator data type, then performs the specified operations. The block converts the result to its output data type using the specified rounding and overflow modes.
9.Constant
- Library:
-
Simulink / Commonly Used Blocks
Simulink / Sources
DSP System Toolbox / Sources
HDL Coder / Commonly Used Blocks
HDL Coder / Sources
Description
The Constant block generates a real or complex constant value signal. Use this block to provide a constant signal input. The block generates scalar, vector, or matrix output, depending on:
-
The dimensionality of the Constant value parameter
-
The setting of the Interpret vector parameters as 1-D parameter
The output of the block has the same dimensions and elements as the Constant value parameter. If you specify for this parameter a vector that you want the block to interpret as a vector, select the Interpret vector parameters as 1-D check box. Otherwise, if you specify a vector for the Constant value parameter, the block treats that vector as a matrix.
10.Temperature Source
- Library:
-
Simscape / Foundation Library / Thermal / Thermal Sources
Description
The Temperature Source block represents an ideal source of thermal energy that is powerful enough to maintain specified temperature at its outlet regardless of the heat flow consumed by the system.
The source generates constant absolute temperature, defined by the Temperature parameter value.
11.Convective Heat Transfer
- Library:
-
Simscape / Foundation Library / Thermal / Thermal Elements
Description
The Convective Heat Transfer block represents a heat transfer by convection between two bodies by means of fluid motion. The transfer is governed by the Newton law of cooling:
Q=k⋅A⋅(TA−TB),
where:
-
Q is heat flow.
-
k is convection heat transfer coefficient.
-
A is surface area.
-
D is distance between layers (that is, thickness of material).
-
TA and TB are temperatures of the two bodies.
Connections A and B are thermal conserving ports associated with the points between which the heat transfer by convection takes place. The block positive direction is from port A to port B. This means that the heat flow is positive if it flows from A to B.
12.Temperature Sensor
- Library:
- Thermal Sensors
Description
The Temperature Sensor block represents an ideal temperature sensor, that is, a device that determines the temperature differential measured between two points without drawing any heat.
Connections A and B are thermal conserving ports that connect to the two points where temperature is being monitored. Port T is a physical signal port that outputs the temperature differential value.
The block positive direction is from port A to port B. The measured temperature is determined as T = TA – TB.
13.Thermal Reference
- Library:
- Thermal Elements
Description
The Thermal Reference block represents a thermal reference point, that is, a point with an absolute zero temperature, with respect to which all the temperatures in the system are determined.
14.PS-Simulink Converter
- Library:
-
Simscape / Utilities
Description
The PS-Simulink Converter block converts a physical signal into a Simulink® output signal. Use this block to connect outputs of a Simscape™ physical network to Simulink scopes or other Simulink blocks.
15.Solver Configuration
- Library:
-
Simscape / Utilities
Description
Each physical network represented by a connected Simscape™ block diagram requires solver settings information for simulation. The Solver Configuration block specifies the solver parameters that your model needs before you can begin simulation.
Each topologically distinct Simscape block diagram requires exactly one Solver Configuration block to be connected to it.
16.Electrical Reference
- Library:
- Electrical Elements
Description
The Electrical Reference block represents an electrical ground. Electrical conserving ports of all the blocks that are directly connected to ground must be connected to an Electrical Reference block. A model with electrical elements must contain at least one Electrical Reference block.
Compare the resultants graph for different area of contact of heat
Now we will be changing the contact temperature by 287k, 310k, 324k.
1) results at 287k
2)results at 310k
3 )results at 324k
Result explanation.
For a 10 cell series lithium ion battery model we simulate the thermal effects and compare life cycle performance at various temperatures, charge & discharge rates using MATLAB. results are as follows
1-10 cells as we are simulating thermal effect on we give Cyclic Discharge Profile to circuit the drop you can see above results all conditions it is same but when show temperature rise high.
so as we give temp of results at 287 k temp is near to 330k
in condition two we give temp 310 k temp is near to 345 k
in condition two we give temp 324 k temp is near to 355 k
Conclusion
MATLAB library model parameters were evaluated for its life cycle and thermal effects parameters. A battery pack with 10 cells connected in series also made with a source of discharging cycle.
The thermal effects of battery pack at different ambient temperatures for cycling discharging has been analysed and plotted. The life cycle performance also evaluated for individual cells and overall battery pack.