Nickel-Metal Hydride Battery Simplified Simulink Model using Matlab All Rights Reserved Copyright (C) Siam Bee Technologies 2015 1 MATLAB Version Bee Technologies
Jul 22, 2015
Nickel-Metal Hydride Battery Simplified Simulink Model
using Matlab
All Rights Reserved Copyright (C) Siam Bee Technologies 2015 1
MATLAB Version
Bee Technologies
Contents
1. Benefit of the Model 2. Model Feature 3. Simulink Model of Ni-Mh Battery 4. Concept of the Model 5. Pin Configurations 6. Ni-Mh 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 – 1.35Ah (0.2C discharge) 6.2.2 Discharge Time Waveform – 1.35Ah (1.0C discharge) 6.2.3 Discharge Time Waveform – 1.35Ah (2.0C 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=7 7.1.2 Charge Time Waveform - NS=7 7.2.1 Discharge Time Circuit - NS=7 7.2.2 Discharge Time Waveform - NS=7 7.3 Charge & Discharge Time (Simulation Settings)
8. Port Specifications
Simulation Index
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1. Benefit of the Model
• The model enables circuit designer to predict and optimize Ni-Mh battery
runtime and circuit performance.
• The model can be easily adjusted to your own Ni-Mh 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 Ni-Mh Battery Simplified Simulink Model is for users who require the
model of a Ni-MH Battery as a part of their system.
• The model accounts for Battery Voltage(Vbat) vs. Battery Capacity Level
(SOC) Characteristic, so it can perform battery charge and discharge time at
various current rate conditions.
• 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 Ni-Mh Battery
5
Equivalent Circuit of Ni-Mh Battery Model using Matlab
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4. Concept of the Model
6
Ni-Mh 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 Ni-Mh cells are in series to
increase battery voltage level.
Output Characteristics
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5. Pin Configurations
• From the Ni-Mh Battery specification, the model is characterized by setting parameters C,
NS, SOC and TSCALE.
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Model Parameters:
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Probe
“SOC”
C is the amp-hour battery capacity [Ah]
– e.g. C = 0.3, 1.4, or 2.8 [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. Ni-Mh Battery Specification (Example)
• The battery information refer to a battery part number HF-A1U of SANYO.
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Table 1
Nominal Voltage 1.2V
Capacity
Typical 1350mAh
Minimum 1250mAh
Charging Current Time 1350mA about 1.1h
Discharge cut-off voltage 1.0V
Battery capacity
[Typ.] is input as a
model parameter
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6.1 Charge Time Characteristic
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• Capacity: 1.35Ah • Charging Current: 1.35A about 1.1hrs
20°C
Datasheet Simulation
SOC=0 means battery
start from 0% of
capacity (empty)
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(Second)
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6.1.1 Charge Time Characteristic Simulation Circuit
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Input Voltage
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• Capacity: 1.35Ah • Charging Current: 1.35A about 1.1hrs
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 3900
AbsTol auto
InitialStep auto
ZcThreshold auto
MaxConsecutiveZCs 1000
NumberNewtonIterations 1
MaxStep 1
MinStep auto
MaxConsecutiveMinStep 1
RelTol 1e-3
SolverMode Auto
Solver ode23t b
SolverName ode23t b
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 0.2C, 1.0C, and 2.0C discharge rates.
Battery starts from
100% of capacity
(fully charged)
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13
0.2C discharge (0.27A)
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6.2.1 Discharge Time Waveform 1.35Ah (0.2C discharge)
• Nominal Voltage: 1.2 [Vdc] /Cell
• Discharge cut-off voltage: 1.0V
• Capacity: 1.35Ah
• 0.2C discharge (0.27A)
(Second)
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14
1.0C discharge (1.35A)
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6.2.2 Discharge Time Waveform 1.35Ah (1.0C discharge)
• Nominal Voltage: 1.2 [Vdc] /Cell
• Discharge cut-off voltage: 1.0V
• Capacity: 1.35Ah
• 1.0C discharge (1.35A)
(Second)
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15
2.0C discharge (2.7A)
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6.2.3 Discharge Time Waveform 1.35Ah (2.0C discharge)
• Nominal Voltage: 1.2 [Vdc] /Cell
• Discharge cut-off voltage: 1.0V
• Capacity: 1.35Ah
• 2.0C discharge (2.7A)
(Second)
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6.2.4 Discharge Time Characteristic Simulation Settings
Table 3: Simulation settings
Property Value
StartTime 0
StopTime 17802, 3450, 1650
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
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Datasheet
• Nominal Voltage: 1.2 [Vdc] /Cell
• Discharge cut-off voltage: 1.0V
• Capacity: 1.35Ah
• Discharge: 0.27A, 1.35A, 2.7A
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
0 250 500 750 1000 1250 1500
Cell
Vo
ltag
e [V
]
Discharge Capacity [mAh]
0.2C (270mA)
1.0C (1350mA)
2.0C (2700mA)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 1 2 3 4 5
Actu
al C
apacity
(% o
f R
ate
d C
apacity)
Discharge Rate (Multiples of C)
Mesurement
Simulation
2700mA
Simulation
1350mA 270mA
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6.3.1 Vbat vs. SOC Characteristic Simulation Circuit
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• Battery voltage vs. SOC are simulated at 0.2C, 1.0C, and 2.0C discharge rates.
• Nominal Voltage: 1.2 [Vdc] /Cell
• Discharge cut-off voltage: 1.0V
• Capacity: 1.35Ah
• Discharge Current: 0.27A, 1.35A, 2.7A
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 17802, 3450, 1650
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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Voltage - Rated 8.4V
Capacity 1500mAh
Structure 1 Row x 7 Cells Side to Side
Number of Cells 7
• The battery information refer to a battery part number HHR-150AAB01F7
of Panasonic.
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7. Extend the number of Cell (Example)
The number of cells
in series is input as
a model parameter Basic Specification
Ni-MH needs 7
cells to reach this
voltage level
2.1
4.8
VoltageNominal MH-Ni
RatedVoltageNS
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7.1.1 Charge Time Circuit NS=7
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Input Voltage
Number of Cells
1 minute into a second
(in simulation)
• Capacity: 1.5Ah • Charging Current: 1.5A about 1.2hrs
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7.1.2 Charge Time Waveform NS=7
• Capacity: 1.5Ah • Charging Current: 1.5A about 1.2hrs
BATTERY PACK NIMH 8.4V
Number of Cells: 7
20°C
(min.)
Datasheet Simulation
SOC=0 means battery
start from 0% of
capacity (empty)
1 minute into a second
(in simulation)
1 Cell
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7.2.1 Discharge Time Circuit NS=7
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• Voltage - Rated: 8.4V
• Capacity: 1.5Ah
• Discharge Current: 1.5A (1.0C)
Number of Cells
1 minute into a second
(in simulation)
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7.2.2 Discharge Time Waveform NS=3
• Voltage - Rated: 8.4V • Capacity: 1.5Ah • Discharge Current: 1.5A
BATTERY PACK NIMH 8.4V
Number of Cells: 7
20°C
(min.)
Datasheet Simulation
battery starts from 100%
of capacity (fully charged)
1 minute into a second
(in simulation)
1 Cell
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7.3 Charge & Discharge Time Simulation Settings
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Table 5: Simulation settings
Property Value
StartTime 0
StopTime 72, 57.5
AbsTol auto
InitialStep auto
ZcThreshold auto
MaxConsecutiveZCs 1000
NumberNewtonIterations 1
MaxStep 0.01
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
26 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
27
Simulations Folder name
1. Charge Time Characteristic..................................................
2. Discharge Time Characteristic..............................................
3. Vbat vs. SOC Characteristic...................................................
4. Charge Time Characteristic – NS=7......................................
5. Discharge Time Characteristic – NS=7..................................
Charge_Time
Discharge_Time
Discharge_SOC
Charge_Time(NS)
Discharge_Time(NS)
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