Battery Management Systems: Accurate State-of-Charge Indication for Battery-Powered Applications describes the field of State-of-Charge (SoC) indication for rechargeable batteries. With the emergence of battery-powered devices accurately estimating the battery SoC, and even more important the remaining time of use, becomes more and more important. An overview of the state-of-the-art of SoC indication methods including available market solutions from leading semiconductor companies, e.g. Texas Instruments, Microchip, Maxim, is given in the first part of this book. Furthermore, a universal SoC indication system that enables 1% or better accuracy under all realistic user conditions is developed. A possible integration with a newly developed ultra-fast recharging algorithm is also described. The contents of this book builds further on the contents of the first volume in the Philips Research Book Series, Battery Management Systems - Design by Modelling. Since the subject of battery SoC indication requires a number of disciplines, this book covers all important disciplines starting from (electro)chemistry to understand battery behaviour, via mathematics to enable modelling of the observed battery behaviour and measurement science to enable accurate measurement of battery variables and assessment of the overall accuracy, to electrical engineering to enable an efficient implementation of the developed SoC indication system. It will therefore serve as an important source of information for any person working in engineering and involved in battery management.
Author(s): Valer Pop, Henk Jan Bergveld, Dmitry Danilov, Paul P.L. Regtien, Peter H.L. Notten
Edition: 1
Year: 2008
Language: English
Pages: 238
Table of contents......Page 7
List of abbreviations......Page 10
List of symbols......Page 12
1.1 Battery Management Systems......Page 20
1.2 State-of-Charge definition......Page 22
1.3 Goal and motivation of the research described in this book......Page 23
1.4 Scope of this book......Page 25
1.5 References......Page 26
2.2 Battery technology and applications......Page 29
2.2.1 General operational mechanism of batteries......Page 31
2.2.2 Battery types and characteristics......Page 32
2.3 History of State-of-Charge indication......Page 34
2.4 A general State-of-Charge system......Page 41
2.5 Possible State-of-Charge indication methods......Page 42
2.5.1 Direct measurement......Page 44
2.5.2 Book–keeping systems......Page 50
2.5.3 Adaptive systems......Page 52
2.5.4 Summary......Page 55
2.6 Commercial State-of-Charge indication systems......Page 56
2.7 Conclusions......Page 59
2.8 References......Page 60
3.2 Battery measurements and modelling for the State-of-Charge indication algorithm......Page 64
3.2.1 EMF measurement and modelling......Page 65
3.2.2 Overpotential measurement and modelling......Page 67
3.3 States of the State-of-Charge algorithm......Page 69
3.4 Main issues of the algorithm......Page 71
3.4.1 EMF measurement, modelling and implementation......Page 72
3.4.2 Overpotential measurement, modelling and implementation......Page 74
3.4.3 Adaptive systems......Page 75
3.6 Conclusions......Page 76
3.7 References......Page 77
4.1 EMF measurement......Page 79
4.2.1 Equilibrium detection......Page 85
4.2.2 Existing voltage-relaxation models used for voltage prediction......Page 86
4.2.3 A new voltage-relaxation model......Page 89
4.2.4 Implementation aspects of the voltage-relaxation model......Page 91
4.2.5 Comparison of results obtained with the different voltage-relaxation models......Page 97
4.2.6 Summary......Page 98
4.3 Hysteresis......Page 99
4.4 Electro-Motive Force modelling......Page 102
4.6 References......Page 109
5.1.1 Overpotential measurements involving partial charge/discharge steps......Page 111
5.1.2 Overpotential measurements involving full (dis)charge steps......Page 116
5.2.1 Overpotential modelling......Page 119
5.2.2 Simulation results......Page 120
5.3 Conclusions......Page 124
5.4 References......Page 125
6.1.1 Li-ion battery aging......Page 126
6.1.2 Q[sub(max)] measurements......Page 128
6.2.1 The voltage-relaxation model as a function of battery aging......Page 129
6.2.2 EMF GITT measurement results obtained for aged batteries......Page 135
6.2.3 The charge/discharge Electro-Motive Force difference as a function of battery aging......Page 140
6.2.4 EMF modelling as a function of battery aging......Page 145
6.3.1 Overpotential measurements as a function of aging......Page 147
6.4.1 Electro-Motive Force adaptive system......Page 152
6.4.2 Overpotential adaptive system......Page 155
6.5 Conclusions......Page 156
6.6 References......Page 157
7.1 Introduction......Page 159
7.2.1 A new SoC algorithm......Page 160
7.2.2 Implementation aspects of the SoC algorithm......Page 164
7.3 Results obtained with the algorithm using fresh batteries......Page 165
7.4.1 Uncertainty in the real-time SoC evaluation system......Page 169
7.4.2 The SoC uncertainty......Page 172
7.4.3 The remaining run-time uncertainty......Page 175
7.5.1 A new State-of-Charge-Electro-Motive Force relationship......Page 178
7.5.2 A new State-of-Charge-left model......Page 179
7.5.3 Determination of the parameters of the new models......Page 180
7.5.4 Test results......Page 183
7.5.5 Uncertainty analysis......Page 187
7.6.1 The bq26500 SoC indicator......Page 188
7.6.2 Comparison of the two SoC indicators......Page 190
7.7 Conclusions......Page 192
7.8 References......Page 193
8.1 Introduction......Page 195
8.2 Implementation aspects of the overpotential adaptive system......Page 196
8.3 SoC=f(EMF) and SoC[sub(l)] adaptive system......Page 197
8.4 Results obtained with the adaptive SoC system......Page 199
8.5 Uncertainty analysis......Page 202
8.6 Results obtained with other Li-based battery......Page 203
8.6.1 EMF and SoC[sub(l)] modelling results obtained for the Li-based battery......Page 204
8.6.2 Experimental results......Page 210
8.7.1 Hardware design of the evaluation board......Page 214
8.7.2 Software design of the evaluation board......Page 218
8.7.3 Measurement results......Page 219
8.7.4 Boostcharging......Page 222
8.8 Conclusions......Page 232
8.9 References......Page 233
9. General conclusions......Page 235
