Lead-Acid Battery Simplified Simulink Model
using Matlab
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MATLAB Version
Bee Technologies
Contents
1. Benefit of the Model 2. Model Feature 3. Simulink Model of Lead-Acid Battery 4. Concept of the Model 5. Pin Configurations 6. Lead-Acid 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 6.2.1 Discharge Time Waveform - 50Ah (0.1C discharge) 6.2.2 Discharge Time Waveform - 50Ah (0.23C discharge) 6.2.3 Discharge Time Waveform - 50Ah (0.65C discharge) 6.2.4 Discharge Time Waveform - 50Ah (1.0C discharge) 6.2.5 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=3 7.1.2 Charge Time Waveform - NS=3 7.2.1 Discharge Time Circuit - NS=3 7.2.2 Discharge Time Waveform - NS=3 7.3 Charge & Discharge Time (Simulation Settings)
8. Port Specifications
Simulation Index
2 All Rights Reserved Copyright (C) Siam Bee Technologies 2015
1. Benefit of the Model
• The model enables circuit designer to predict and optimize Lead-Acid
battery runtime and circuit performance.
• The model can be easily adjusted to your own Lead-Acid 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.
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• This Lead-Acid Battery Simplified Simulink Model is for users who require
the model of a Lead-Acid 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.
2. Model Feature
4
Battery Circuit Model
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2
MINUS
1
PLUS
3. Simulink Model of Lead-Acid Battery
5
Equivalent Circuit of Lead-Acid Battery Model using Matlab
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4. Concept of the Model
6
Lead-Acid battery
Simplified 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 Lead-Acid cells are in series
to increase battery voltage level.
Output Characteristics
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5. Pin Configurations
• From the Lead-Acid Battery specification, the model is characterized by setting parameters
C, NS, SOC and TSCALE.
7
Model Parameters:
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Probe
“SOC”
C is the amp-hour battery capacity [Ah]
– e.g. C = 1, 50, or 100 [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(in the real world)
into a second(in simulation)
– e.g. TSCALE=60 turns 60s or 1min (in the real world) into a second(in simulation), TSCALE=3600 turns 3600s or 1h into a second.
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6. Lead-Acid Battery Specification (Example)
• The battery information refer to a battery part number MSE Series of GS YUASA.
8
Battery capacity is input
as a model parameter
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Table 1
Nominal Voltage 2.0 [Vdc] /Cell
Capacity 50Ah
Rated Charge 0.1C10A
Voltage Set 2.23 [Vdc] /Cell
Charging Time 24 [hours] @ 0.1C10A
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6.1 Charge Time Characteristic
9
• Voltage Set: 2.23V /Cell • Charging Current: 5.0A (0.1C Charge) • Charging Time: 24 [hours] @ 0.1C10A
Current: 5A (0.1C10A)
Voltage Set=2.23V
Datasheet Simulation
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%SOC
(Second)
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6.1.1 Charge Time Characteristic Simulation Circuit
10
Over-Voltage Protector:
(Charging Voltage 1) - VF of Diode
Input Voltage
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SOC=0 means battery
starts from 0% of
capacity (empty)
Charging Current
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6.1.2 Charge Time Characteristic Simulation Settings
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Table 2: Simulation settings
Property Value
StartTime 0
StopTime 100000
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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6.2 Discharge Time Characteristic
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• Battery voltage vs. time are simulated at 0.1C, 0.23C, 0.65C and 1.0C discharge rates.
Datasheet
• Battery starts from 100% of capacity (fully charged)
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13
0.1C discharge (5A)
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6.2.1 Discharge Time Waveform 50Ah (0.1C discharge)
• Nominal Voltage: 2.0 [Vdc] /Cell
• Capacity: 50Ah
• 0.1C discharge (5.0A)
(Second)
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14
0.23C discharge (11.5A)
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6.2.2 Discharge Time Waveform 50Ah (0.23C discharge)
• Nominal Voltage: 2.0 [Vdc] /Cell
• Capacity: 50Ah
• 0.23C discharge (11.5A)
(Second)
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15
0.65C discharge (32.5A)
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6.2.3 Discharge Time Waveform 50Ah (0.65C discharge)
• Nominal Voltage: 2.0 [Vdc] /Cell
• Capacity: 50Ah
• 0.65C discharge (32.5A)
(Second)
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16
1.0C discharge (50A)
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6.2.4 Discharge Time Waveform 50Ah (1.0C discharge)
• Nominal Voltage: 2.0 [Vdc] /Cell
• Capacity: 50Ah
• 1.0C discharge (50A)
(Second)
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17 All Rights Reserved Copyright (C) Bee Technologies Corporation 2015
6.2.4 Discharge Time Characteristic Simulation Settings
Table 3: Simulation settings
Property Value
StartTime 0
StopTime 36000, 13932, 3420, 1836
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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6.3 Vbat vs. SOC Characteristic
18 All Rights Reserved Copyright (C) Bee Technologies Corporation 2015
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 1 2 3
(% o
f R
ate
d C
apacity)
Discharge Rate (Multiples of C)
Mesurement
Simulation
Datasheet Simulation
@25C
@25C
• Nominal Voltage: 2.0 [Vdc] /Cell
• Capacity: 50Ah
• 0.1C, 0.25C, 0.6C, 1.0 and 3.0C (discharge rates)
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6.3.1 Vbat vs. SOC Characteristic Simulation Circuit
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Battery starts from
100% of capacity
(fully charged)
• Battery voltage vs. SOC are simulated at 0.1C, 0.25C, 0.6C and 1.0C discharge rates.
Discharge Current
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6.3.2 Vbat vs. SOC Characteristic Simulation Settings
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Table 4: Simulation settings
Property Value
StartTime 0
StopTime 36000, 12600, 3780, 1836
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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• The battery information refer to a battery part number MSE-100-6 of GS YUASA.
21 All Rights Reserved Copyright (C) Bee Technologies Corporation 2015
7. Extend the number of Cell (Example)
Voltage - Rated 6.0 [Vdc] /Cell
Capacity 100Ah
Rated Charge 0.1C10A
Voltage Set 2.23V*3 [Vdc] /Cell
Charging Time 24 [hours] @ 0.1C10A
Basic Specification
Lead-Acid needs 3 cells
to reach this voltage level The number of cells
in series is input as
a model parameter
0.2
6
Acid-Lead
VoltageNominal
RatedVoltageNS
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7.1.1 Charge Time Circuit NS=3
22
Over-Voltage Protector:
(Voltage Set 3) - VF of Diode
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Number of Cells
1 hour into a second (in
simulation)
Charging Current
Input Voltage
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23
• Voltage Set: 2.23V 3
• Capacity: 100Ah
• Charging Current: 10A (0.1 Charge)
Voltage Set=6.69V
(hour)
The battery needs 24 hours to be fully charged
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7.1.2 Charge Time Waveform NS=3
Current: 10A (0.1C)
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7.2.1 Discharge Time Circuit NS=3
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• Battery voltage vs. time are simulated at 0.1C discharge rate.
• Nominal Voltage: 2.0V 3
• Capacity: 100Ah
• Discharge Current: 10A (0.1C)
Number of Cells
1 hour into a second
(in simulation)
Discharge Current
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25
(hour)
10A (0.1C) Nominal voltage: 6.0V
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7.2.2 Discharge Time Waveform NS=3
• Nominal Voltage: 2.0V 3
• Capacity: 100Ah
• Discharge Current: 10A (0.1C)
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7.3 Charge & Discharge Time Simulation Settings
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Table 5: Simulation settings
Property Value
StartTime 0
StopTime 24, 10
AbsTol auto
InitialStep auto
ZcThreshold auto
MaxConsecutiveZCs 1000
NumberNewtonIterations 1
MaxStep 0.1
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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8. Port Specifications
27 All Rights Reserved Copyright (C) Bee Technologies Corporation 2015
Table 6
Parameter Simulink Simscape
NS O
C O
TSCALE O
%SOC O
VSOC O
PLUS O
MINUS O
Battery Model
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Simulation Index
28
Simulations Folder name
1. Charge Time Characteristic..................................................
2. Discharge Time Characteristic..............................................
3. Vbat vs. SOC Characteristic...................................................
4. Charge Time Characteristic – NS=3......................................
5. Discharge Time Characteristic – NS=3..................................
Charge_Time
Discharge_Time
Discharge_SOC
Charge_Time(NS)
Discharge_Time(NS)
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