device modeling of li-ion battery matlab/simulink model
TRANSCRIPT
All Rights Reserved Copyright (C) Siam Bee Technologies 2015 1
Lithium-Ion Battery MATLAB/Simulink Model
Bee Technologies
http://www.bee-tech.info/
Device Modeling Service
Charge Characteristic
Discharge Characteristic
Device Modeling
Service MATLAB/Simulink Model
Contents
1. Model Feature 2. MATLAB/Simulink Model of Lithium-Ion Battery 3. Concept of the Model 4. Pin Configurations 5. Li-Ion Battery Specification (Example) 5.1 Charge Time Characteristic 5.1.1 Charge Time Characteristic (Simulation Circuit) 5.1.2 Charge Time Characteristic (Simulation Settings) 5.2 Discharge Time Characteristic (Simulation Circuit) 5.2.1 Discharge Time Waveform - 1400mAh (0.2C discharge) 5.2.2 Discharge Time Waveform - 1400mAh (0.5C discharge) 5.2.3 Discharge Time Waveform - 1400mAh (1.0C discharge) 5.2.4 Discharge Time Characteristic (Simulation Settings) 5.3 Vbat vs. SOC Characteristic 5.3.1 Vbat vs. SOC Characteristic (Simulation Circuit) 5.3.2 Vbat vs. SOC Characteristic (Simulation Settings) 6. Port Specifications
2 All Rights Reserved Copyright (C) Siam Bee Technologies 2015
• This Li-Ion Battery MATLAB/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 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
1. Model Feature
3
Concept Circuit of Li-Ion Battery Circuit Model
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2. MTALAB/Simulink Model of Lithium-Ion Battery
4
Equivalent Circuit of Lithium-Ion Battery Model using MATLAB
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1
VSOC
2
MINUS
1
PLUS
f(x)=0
Solver
Configuration
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_EQV
IBAT
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
3. Concept of the Model
5
Li-Ion battery
MATLAB/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
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VBATT
Voch
(4.24*Ns)-0.07
VIN
5V1
Tscale
100
Soc
+-
V+
-
I+
-
SENSE_IBAT
PSS
PS S
OUTPUT
1
Ns
NS
C
Tscale
%SOC
VSOC
PLUS
MINUS
LI-ION_BATTERY
ICHG
0.5C (700mA)1.4
Capacity
4. 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.
6
Model Parameters:
Probe
“SOC”
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VBATT
Voch
(4.24*Ns)-0.07
VIN
5V1
Tscale
100
Soc
+-
V+
-
I+
-
SENSE_IBAT
PSS
PS S
OUTPUT
1
Ns
NS
C
Tscale
%SOC
VSOC
PLUS
MINUS
LI-ION_BATTERY
ICHG
0.5C (700mA)1.4
Capacity
5. Li-Ion Battery Specification (Example)
• The battery information refer to a battery part number LIR18500 of EEMB BATTERY.
7
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
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5.1 Charge Time Characteristic
8
• Charging Voltage: 4.20V±0.05V
• Charging Current: 700mA (0.5C Charge)
Current=700mA
Voltage=4.20V
Measuremet Data Simulation
SOC=0 means battery start
from 0% of capacity (empty)
%SOC
(Second)
VBATT
Voch
(4.24*Ns)-0.07
VIN
5V1
Tscale
0
Soc
+-V
+-
I+
-
SENSE_IBAT
PSS
PS S
OUTPUT
1
Ns
NS
C
Tscale
%SOC
VSOC
PLUS
MINUS
LI-ION_BATTERY
ICHG
0.5C (700mA)1.4
Capacity
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VBATT
Voch
(4.24*Ns)-0.07
VIN
5V1
Tscale
0
Soc
+-
V+
-
I+
-
SENSE_IBAT
PSS
PS S
OUTPUT
1
Ns
NS
C
Tscale
%SOC
VSOC
PLUS
MINUS
LI-ION_BATTERY
ICHG
0.5C (700mA)1.4
Capacity
5.1.1 Charge Time Characteristic Simulation Circuit
9
Over-Voltage Protector:
(Charging Voltage*1) - VF of Diode
Input Voltage
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5.1.2 Charge Time Characteristic Simulation Settings
10
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
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5.2 Discharge Time Characteristic Simulation Circuit
11
• Battery voltage vs. time are simulated at 0.2C, 0.5C, and 1C discharge rates.
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
IDIS
0.2C (280mA)
1.4
Capacity
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12
0.2C discharge (280mA)
5.2.1 Discharge Time Waveform 1400mAh (0.2C discharge)
• Nominal Voltage: 3.7V
• Discharge cut-off voltage: 2.75V
(Second)
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13
0.5C discharge (700mA)
5.2.2 Discharge Time Waveform 1400mAh (0.5C discharge)
• Nominal Voltage: 3.7V
• Discharge cut-off voltage: 2.75V
(Second)
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14
1.0C discharge (1400mA)
5.2.3 Discharge Time Waveform 1400mAh (1.0C discharge)
• Nominal Voltage: 3.7V
• Discharge cut-off voltage: 2.75V
(Second)
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15
5.2.4 Discharge Time Characteristic Simulation Settings
Table 3: Simulation settings
Property Value
StartTime 0
StopTime 24000, 9600, 4800
AbsTol auto
InitialStep auto
ZcThreshold auto
MaxConsecutiveZCs 1000
NumberNewtonIterations 1
MaxStep 10
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
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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
charg
e C
apacity
(%vs.
0.2
C)
Battery Discharge Current (vs. C Rate)
Mesurement
Simulation
5.3 Vbat vs. SOC Characteristic
16
• Nominal Voltage: 3.7V
• Capacity: 1400mAh (0.2C discharge)
• Discharge cut-off voltage: 2.75V
2.60
2.80
3.00
3.20
3.40
3.60
3.80
4.00
4.20
4.40
-0.200.20.40.60.81
Vo
ltag
e (V
)
Capacity (%)
0.5C
0.2C
1C
Measurement Data Simulation
Simulation Vbat vs. SOC
1
Tscale
100
Soc V+
-
PSS
1
Ns
NS
C
Tscale
%SOC
VSOC
PLUS
MINUS
LI-ION_BATTERY
IDIS
1400mAh*(discharge rate)
1.4
Capacity
100
Cal
VBAT
SOC
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5.3.1 Vbat vs. SOC Characteristic Simulation Circuit
17
Vbat vs. SOC
1
Tscale
100
Soc V+
-
PSS
1
Ns
NS
C
Tscale
%SOC
VSOC
PLUS
MINUS
LI-ION_BATTERY
IDIS
1400mAh*(discharge rate)
1.4
Capacity
100
Cal
VBAT
SOC
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5.3.2 Vbat vs. SOC Characteristic Simulation Settings
18
Table 4: Simulation settings
Property Value
StartTime 0
StopTime 19200
AbsTol auto
InitialStep auto
ZcThreshold auto
MaxConsecutiveZCs 1000
NumberNewtonIterations 1
MaxStep 10
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
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6. Port Specifications
19
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
VIN
5V
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
ICHG
0.5C
IBAT
1.4
Capacity
Battery Model
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