Lithium Ion Battery Simplified Simulink Model using MATLAB

All Rights Reserved Copyright (C) Siam Bee Technologies 2015 1

MATLAB Version

Lithium Ion BatterySimplified Simulink Model using MATLAB

Bee Technologies

Contents

1. Benefit of the Model2. Model Feature3. Simulink Model of Lithium-Ion Battery4. Concept of the Model5. Pin Configurations6. Li-Ion Battery Specification (Example)6.1 Charge Time Characteristic

6.1.1 Charge Time Characteristic (Simulation Circuit)6.1.2 Charge Time Characteristic (Simulation Settings)

6.2 Discharge Time Characteristic (Simulation Circuit)6.2.1 Discharge Time Waveform - 1400mAh (0.2C discharge)6.2.2 Discharge Time Waveform - 1400mAh (0.5C discharge)6.2.3 Discharge Time Waveform - 1400mAh (1.0C discharge)6.2.4 Discharge Time Characteristic (Simulation Settings)

6.3 Vbat vs. SOC Characteristic 6.3.1 Vbat vs. SOC Characteristic (Simulation Circuit) 6.3.2 Vbat vs. SOC Characteristic (Simulation Settings)

7. Extend the number of Cell (Example)7.1.1 Charge Time Circuit - NS=4, TSCALE=36007.1.2 Charge Time Waveform - NS=4, TSCALE=36007.2.1 Discharge Time Circuit - NS=4, TSCALE=36007.2.2 Discharge Time Waveform - NS=4, TSCALE=3600

7.3 Charge & Discharge Time (Simulation Settings)8. Port Specifications

Simulation Index

Appendix Diode

2All Rights Reserved Copyright (C) Siam Bee Technologies 2015

1. Benefit of the Model

• The model enables circuit designer to predict and optimize battery runtime and circuit performance.

• The model can be easily adjusted to your own battery specifications by editing a few parameters that are provided in the datasheet.

• The model is optimized to reduce the convergence error and the simulation time


• This Li-Ion Battery Simplified Simulink Model is for users who require the model of a Li-Ion Battery as a part of their system.

• Battery Voltage(Vbat) vs. Battery Capacity Level (SOC) Characteristic, that can perform battery charge and discharge time at various current rate conditions, are accounted by the model.

• As a simplified model, the effects of cycle number and temperature are neglected.

VSOC

2

MINUS

1

PLUS

VOC

+-

Rtransient_S

+-

Rtransient_L

+-

Rseries

Ibatt

+-

Ctransient_S

+-

Ctransient_L

+-

Capacity

2. Model Feature

4

Battery Circuit Model

All Rights Reserved Copyright (C) Siam Bee Technologies 2015

3. Simulink Model of Lithium-Ion Battery

5

Equivalent Circuit of Lithium-Ion Battery Model using Matlab


1

VSOC

2

MINUS

1

PLUS

f(x)=0

SolverConfiguration

PSS

V+

-

PS S

+-

0.03

RTS

0.034

RTL

IBAT

RTS

CTS

CAH

N

TSCALE

RTCT_S

RTCT_S_EQV

IBAT

RTL

CTL

CAH

N

TSCALE

RTCT_L

RTCT_L_EQVIBAT

RS

N

CAH

RSO

RS_EQV

0.045

RS

PS S

PSS

+

-

U

+

-

U

-K-

-K-

f(u)SOC VOUT

EOCV

I+

-

1800

CTS

15000

CTL

TSCALE

CAH

IBAT

SOC_SETTING

SOC0

CAPACITY

+-

4

%SOC

3

Tscale

2

C

1

NS

4. Concept of the Model

6

Li-Ion batterySimplified Simulink Model

[Spec: C, NS]

Adjustable SOC : 0-100(%)

+

-

• The model is characterized by parameters: C, which represent the battery capacity and SOC, which represent the battery initial capacity level.

• Open-circuit voltage (VOC) vs. SOC is included in the model as a behavioral model.

• NS (Number of Cells in series) is used when the Li-ion cells are in series to increase battery voltage level.

Output Characteristics

All Rights Reserved Copyright (C) Bee Technologies Corporation 2015All Rights Reserved Copyright (C) Siam Bee Technologies 2015

VBATT

Voch(4.24*Ns)-0.07

VIN5V

1

Tscale

100

Soc

+-V

+-

I+

-

SENSE_IBAT

PSS

PS S

OUTPUT

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.5C (700mA)1.4

Capacity

5. Pin Configurations

C is the amp-hour battery capacity [Ah]

– e.g. C = 0.2, 1.4, or 2.0 [Ah]

NS is the number of cells in series

– e.g. NS=1 for 1 cell battery, NS=2 for 2 cells battery (battery voltage is double from 1 cell)

SOC is the initial state of charge in percent

– e.g. SOC=0 for a empty battery (0%), SOC=100 for a full charged battery (100%)

TSCALE turns TSCALE seconds into a second

– e.g. TSCALE=60 turns 60s or 1min into a second TSCALE=3600 turns 3600s or 1h into a second

• From the Li-Ion Battery specification, the model is characterized by setting parameters C, NS, SOC and TSCALE.

7

Model Parameters:

All Rights Reserved Copyright (C) Bee Technologies Corporation 2015

Probe “SOC”


VBATT

Voch(4.24*Ns)-0.07

VIN5V

1

Tscale

100

Soc

+-V

+-

I+

-

SENSE_IBAT

PSS

PS S

OUTPUT

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.5C (700mA)1.4

Capacity

6. Li-Ion Battery Specification (Example)

• The battery information refer to a battery part number LIR18500 of EEMB BATTERY.

8

Battery capacity is input as a model parameter

Battery capacity is input as a model parameter

Nominal Voltage 3.7V

Nominal Capacity

Typical 1400mAh (0.2C discharge)

Charging Voltage 4.20V±0.05V

Charging Std. Current 700mA

Max Current

Charge 1400mA

Discharge 2800mA

Discharge cut-off voltage 2.75V


Table 1


6.1 Charge Time Characteristic

9

• Charging Voltage: 4.20V±0.05V• Charging Current: 700mA (0.5C Charge)

Current=700mA

Voltage=4.20V

Datasheet Simulation

SOC=0 means battery start from 0% of capacity (empty)SOC=0 means battery start from 0% of capacity (empty)


%SOC

(Second)

VBATT

Voch(4.24*Ns)-0.07

VIN5V

1

Tscale

0

Soc

+-V

+-

I+

-

SENSE_IBAT

PSS

PS S

OUTPUT

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.5C (700mA)1.4

Capacity


VBATT

Voch(4.24*Ns)-0.07

VIN5V

1

Tscale

0

Soc

+-V

+-

I+

-

SENSE_IBAT

PSS

PS S

OUTPUT

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.5C (700mA)1.4

Capacity

6.1.1 Charge Time Characteristic Simulation Circuit

10

Over-Voltage Protector: (Charging Voltage*1) - VF of Diode

Over-Voltage Protector: (Charging Voltage*1) - VF of Diode

Input VoltageInput Voltage


6.1.2 Charge Time Characteristic Simulation Settings

11All Rights Reserved Copyright (C) Bee Technologies Corporation 2015

Table 2: Simulation settings

Property Value

StartTime 0

StopTime 12000

AbsTol auto

InitialStep auto

ZcThreshold auto

MaxConsecutiveZCs 1000

NumberNewtonIterations 1

MaxStep 1

MinStep auto

MaxConsecutiveMinStep 1

RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t

SolverType Variable-step

SolverJacobianMethodControl auto

ShapePreserveControl DisableAll

ZeroCrossControl UseLocalSettings

ZeroCrossAlgorithm Adaptive

SolverResetMethod Fast


6.2 Discharge Time Characteristic Simulation Circuit


• Battery voltage vs. time are simulated at 0.2C, 0.5C, and 1C discharge rates.

battery starts from 100% of capacity (fully charged)battery starts from 100% of capacity (fully charged)

VBAT

1

Tscale

100

Soc

V+

-

PSS

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

IDIS0.2C (280mA)

1.4

Capacity


13

0.2C discharge (280mA)


6.2.1 Discharge Time Waveform 1400mAh (0.2C discharge)

• Nominal Voltage: 3.7V• Discharge cut-off voltage: 2.75V

(Second)


14





(Second)


15





(Second)



6.2.4 Discharge Time Characteristic Simulation Settings


Property Value

StartTime 0

StopTime 24000, 9600, 4800

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 10

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 0.2 0.4 0.6 0.8 1

Dis

char

ge C

apac

ity(%

vs. 0

.2C

)

Battery Discharge Current (vs. C Rate)

Mesurement

Simulation

6.3 Vbat vs. SOC Characteristic

17

• Nominal Voltage: 3.7V• Capacity: 1400mAh (0.2C discharge)• Discharge cut-off voltage: 2.75V

2.602.803.003.203.403.603.804.004.204.40

-0.200.20.40.60.81

Vo

ltag

e (V

)

Capacity (%)

0.5C

0.2C

1C

Datasheet Simulation

Simulation


Vbat vs. SOC

1

Tscale

100

Soc V+

-

PSS

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

IDIS1400mAh*(discharge rate)

1.4

Capacity

100

Cal

VBAT

SOC


6.3.1 Vbat vs. SOC Characteristic Simulation Circuit


Vbat vs. SOC

1

Tscale

100

Soc V+

-

PSS

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

IDIS1400mAh*(discharge rate)

1.4

Capacity

100

Cal

VBAT

SOC


6.3.2 Vbat vs. SOC Characteristic Simulation Settings



Property Value

StartTime 0

StopTime 19200

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 10

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








VBATT

Voch(4.2*Ns)-70m

VIN20.5V

3600

Tscale

0

Soc

+-V

+-

I+

-

SENSE_IBAT

PSS

PS S

OUTPUT

4

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.2C (880mA)4.4

Capacity

• The battery information refer to a battery part number PBT-BAT-0001 of BAYSUN Co., Ltd.

20

The number of cells in series is input as a model parameter

The number of cells in series is input as a model parameter

Output Voltage DC 12.8~16.4V

Capacity of Approximately 4400mAh

Input Voltage DC 20.5V

Charging Time About 5 hours

Basic Specification

Li-ion needs 4 cells to reach this voltage

level

Li-ion needs 4 cells to reach this voltage

level


7. Extend the number of Cell (Example) NS=4, TSCALE=3600

1 hour into a second (in simulation)

1 hour into a second (in simulation)


VBATT

Voch(4.218*Ns)-12m

VIN20.5V

3600

Tscale

0

Soc

+-V

+-

I+

-

SENSE_IBAT

PSS

PS S

OUTPUT

4

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.2C (880mA)4.4

Capacity

7.1.1 Charge Time Circuit NS=4, TSCALE=3600

21

Input VoltageInput Voltage

Over-Voltage Protector: (Charging Voltage 4) - VF of Diode

Over-Voltage Protector: (Charging Voltage 4) - VF of Diode


Number of CellsNumber of Cells


22

• Input Voltage: 20.5V• Charging Voltage: 16.8V• Charging Current: 880mA (0.2 Charge)

Current=880mA

Voltage=16.8V

Capacity=100%

(hour)

The battery needs 5 hours to be fully charged


7.1.2 Charge Time Waveform NS=4, TSCALE=3600

BATTERY PACK LI-ION 12.8~16.4VNumber of Cells: 4


VBAT

3600

Tscale

100

Soc

V+

-

PSS

4

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

IDIS0.5C (2200mA)

4.4

Capacity

7.2.1 Discharge Time Circuit NS=4, TSCALE=3600


Number of CellsNumber of Cells

• Output Voltage: 12.8~16.4V• Capacity: 4400mAh• Discharge Current: 2200mA (0.5C)


24

2200mA (0.5C)

16.4V

12.8V

Output voltage range


7.2.2 Discharge Time Waveform NS=4, TSCALE=3600

• Output Voltage: 12.8~16.4V• Capacity: 4400mAh• Discharge Current: 2200mA (0.5C)

BATTERY PACK LI-ION 12.8~16.4VNumber of Cells: 4

(hour)


7.3 Charge & Discharge Time Simulation Settings



Property Value

StartTime 0

StopTime 8, 3

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 0.01

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








8. Port Specifications


Table 6

Parameter Simulink Simscape

NS O

C O

TSCALE O

%SOC O

VSOC O

PLUS O

MINUS O

Voch(4.2*Ns)-6.5m

VSOC

VIN5V

VBAT60

Tscale

0

Soc

+-V

+-

SENSE_VBAT

I+

-

SENSE_IBAT

PS S

PS S

1

Ns

NS

C

Tscale

%SOC

VSOC

PLUS

MINUS

LI-ION_BATTERY

ICHG0.5C

IBAT

1.4

Capacity

Battery Model


Simulation Index

27

Simulations Folder name

1. Charge Time Characteristic..................................................

2. Discharge Time Characteristic..............................................

3. Vbat vs. SOC Characteristic...................................................

4. Charge Time Characteristic - NS=4, TSCALE=3600.............

5. Discharge Time Characteristic - NS=4, TSCALE=3600.........

Charge_Time

Discharge_Time

Discharge_SOC

Charge_Time(NS)

Discharge_Time(NS)


Appendix


If Diode is error, Please choice Diode of SPICE-Compatiable Semiconductors/Diode

Appendix


Setting of Diode

Emission coefficient ,ND Default Value change 0.01

Engineering

Lithium Ion Battery Simplified Simulink Model using MATLAB