WO2009013464A1 - Gestion de batterie - Google Patents

Gestion de batterie Download PDF

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Publication number
WO2009013464A1
WO2009013464A1 PCT/GB2008/002447 GB2008002447W WO2009013464A1 WO 2009013464 A1 WO2009013464 A1 WO 2009013464A1 GB 2008002447 W GB2008002447 W GB 2008002447W WO 2009013464 A1 WO2009013464 A1 WO 2009013464A1
Authority
WO
WIPO (PCT)
Prior art keywords
cell
storage element
charge storage
charge
control circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2008/002447
Other languages
English (en)
Inventor
William Armstrong
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Frazer Nash Technology Ltd
Original Assignee
Frazer Nash Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Frazer Nash Technology Ltd filed Critical Frazer Nash Technology Ltd
Publication of WO2009013464A1 publication Critical patent/WO2009013464A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/50—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially
    • H02J7/52—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially for charge balancing, e.g. equalisation of charge between batteries
    • H02J7/56—Active balancing, e.g. using capacitor-based, inductor-based or DC-DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/50—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially
    • H02J7/52—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially for charge balancing, e.g. equalisation of charge between batteries
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/50—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially
    • H02J7/52—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially for charge balancing, e.g. equalisation of charge between batteries
    • H02J7/54—Passive balancing, e.g. using resistors or parallel MOSFETs

Definitions

  • This invention relates to battery management, and in particular to a method and apparatus for equalising the charge on a plurality of series connected cells forming a battery.
  • Series strings of storage cells are extensively used in many applications; for example PDA's, laptops, standby power supplies, wind, wave or solar generating systems, and electric vehicles. Inbalances in the charges of these cells tend to occur and grow over time, as the string is charged and discharged. This reduces the efficiency of the charging and discharging process and also limits the life of the battery. It is therefore very important to ensure the uniformity of charge for all cells in a battery string, which is a major part of what is now known as 'managing' the battery. .
  • an apparatus for regulating the output voltages of at least two cells connected in series comprising a charge storage element connectable across each cell, and a control circuit having an input connectable across the charge storage element, wherein the control circuit is arranged to: for each cell, connect the charge storage element across the cell, disconnect the charge storage element from the cell, and connect the charge storage element to the control circuit input to measure the voltage of the cell; compare the measured voltages of each cell, determine a high voltage cell having a voltage higher than at least one other cell, and determine a low voltage cell having a voltage lower than at least one other cell; and connect the charge storage element across the high voltage cell thereby to discharge the high voltage cell, disconnect the charge storage element from the high voltage cell, and connect the charge storage element across the low voltage cell thereby to charge the low voltage cell.
  • the process may be repeated a number of times with a small amount of energy transferred during each complete operation.
  • the invention may discharge a cell with a higher voltage, store the charge in the charge storage element, and use this to charge a cell with a lower voltage, in order to equalise the charges on the cells. This is done using a single charge storage element or capacitor and is thus less bulky and expensive than prior art arrangements.
  • the apparatus has the advantage of being relatively small. Also, the switches operate at substantially zero current, which mitigates switching losses, and allows high frequency switching.
  • the apparatus may also be adapted for use with a further parallel string of cells, by the use of a further set of switches.
  • the apparatus also comprises an inductor connectable between one terminal of each cell and the charge storage element.
  • the control circuit may be arranged to connect the charge storage element to the high voltage cell via the inductor for an 'on' period substantially proportional to the resonant frequency of the LC circuit (for example equal to approximately one half of the resonant frequency), and then to reverse the connections across the high voltage cell for a further 'on' period. This "ringing" action may be repeated to increase the charge in the charge storage element as required. This enables the charge storage element to be charged to a higher level and reduces the energy loss occurring as a result of the operation.
  • control circuit may similarly be arranged to connect the charge storage element across the low voltage cell via the inductor for such an "on” period, and then to reverse the connection across the low voltage cell for a further “on” period. This assists in discharging the capacitor fully.
  • the present invention also provides an apparatus for regulating the output voltage of at least two cells connected in series, the apparatus comprising: a charge storage element; a set of first cell switches for coupling a first terminal of each cell respectively to a first plate of the storage element; a set of second cell switches for coupling a second terminal of each cell respectively to a second plate of the storage element; and a pair of level shifting switches for coupling the first and second plates of the storage element respectively to a control circuit; the control circuit being arranged to operate each of the switches.
  • the apparatus preferably comprises an inductor connectable by means of an inductor switch between the first set of cell switches and the first plate of the storage element.
  • the invention also comprises a method for regulating the output voltage of at least two cells connected in series, comprising (a) connecting a charge storage element across a first cell in the string; (b) isolating the charge storage element from the cell and then connecting the charge storage element to a control circuit; (c) measuring the voltage across on the charge storage element with the control circuit; (d) repeating steps (a)-(c) for the remaining cells of the string in turn; (e) comparing the voltages so as to identify a high voltage cell, which has a higher charge than at least one other cell; (f) connecting the high voltage cell across the charge storage element to charge the charge storage element; (g) determining a low voltage cell having a lower charge than at least one other cell; and (h) connecting the charge storage element across the low voltage cell to charge that cell.
  • the method preferably also comprises, between steps (e) and (f): coupling an inductor to one plate of the charge storage element, connecting the cell in step (f) for an "on" period substantially proportional to the resonant frequency of the LC circuit, and then reversing the connection across the cell for a further "on” period further to charge the charge storage element.
  • the method may also comprise, between steps (g) and (h): coupling an inductor to one plate of the charge storage element, connecting the cell in step (h) for an "on” period as defined above, and then reversing the connection across the cell for a further "on” period.
  • Figure 1 is a circuit diagram of an apparatus according to an embodiment of the present invention
  • Figure 2 is a circuit diagram of a switching circuit suitable for use in the apparatus of Figure 1.
  • a battery comprises a string of cells 2, including adjacent cells labeled n+1, n, and n-1.
  • switches required to describe the functions in relation to the cell n are shown in the diagram. These include a first cell switch 4 for coupling the positive side of the cell n to a first or upper plate 12 of a charge storage element in the form of a capacitor 14.
  • a further first cell switch 6 is provided for coupling the positive side of the adjacent cell n-1 to the upper plate 12 of a capacitor 14. Further first cell switches will be required for connecting the positive sides of the remaining cells in the string to the upper plate 12 of the capacitor.
  • a second cell switch 8 is arranged to couple the negative side of the cell n to the second or lower plate 16 of the capacitor 14.
  • a further second cell switch 10 is arranged to couple the negative end of the adjacent cell n+1 to the lower plate 16 of the capacitor 14. Further second cell switches will be required for the remaining cell of the string. Thus it will be understood that two switches are provided for each inter-cell node; one first cell switch and one second cell switch corresponding to the adjacent cells.
  • the switches may conveniently be switching circuits, for example as shown in Figure 2. These circuits comprise two N channel mosfet devices connected such that they have common gate and source connections, as will be described later.
  • each of the cell switches is connected to a control circuit 18 (as shown by broken lines), for operating the switches.
  • the circuit also comprises an inductor 20 which is connectable between the first cell switches 4, 6 and the upper plate 12 of the capacitor 14 via an inductor switch 22.
  • a pair of level shifting switches 24, 26 are operable by the control circuit 18 to couple the upper and lower plates 12, 16 of the capacitor 14 respectively to the control circuit 18.
  • the circuit is first used as a multiplexer to measure the voltage across each cell. This is done by connecting the capacitor 14 across a first cell n in the string using the respective first and second cell switches 4, 8, with the inductor switch 22 closed to short circuit the inductor 20. After the cell switches 4, 8 have been closed for a sufficiently long time period, the capacitor 14 will charge through the on resistance of the switches to a voltage substantially the same as the voltage of the cell n. The first and second switches 4, 8 are then opened, with the charge remaining in the capacitor 14. The level shifting switches 24, 26 are then closed such that the voltage on the capacitor 14 is presented to an input of the control circuit 18. This may for example be a microprocessor analogue to digital converter input.
  • the voltage of the cell n is thus measured by the control circuit 18. This process is repeated for each of the remaining cells in the string in turn.
  • the apparatus acts as a multiple input/single output system, or multiplexer, which traps and then level shifts the voltage of any cell in the string, such that a low voltage control circuit can read the voltage level on the cell. High string voltages are blocked from the control circuit by the alternate switching action of the level shifting switches 24, 26 and the first and second cell switches e.g. 4, 8.
  • the control circuit After the voltages across each cell have been ascertained by the control circuit, it is possible to compare them and identify a cell which has a lower voltage than other cells in the string.
  • the inductor 20 is then connected between the first switches 4, 6 and the top plate 12 of the capacitor 14 by opening the inductor switch 22.
  • the capacitor 14 will be charged with a residual voltage following its use in the multiplexing mode.
  • the high voltage cell n is connected across the capacitor 14 using the respective first and second cell switches 4, 8 via the inductor 20.
  • Conventional current will thus start to flow in the inductor 20 and consequently the capacitor charge will increase.
  • the cell switches 4,8 are closed for an "on" period substantially proportional to the resonant frequency of the LC circuit.
  • the "on" period may be approximately one half of the resonant frequency.
  • the inductor current will have fallen back to zero and the capacitor will be charged to approximately twice the difference between the residual voltage and the voltage across the high voltage cell n.
  • connections are then reversed by connecting the positive terminal of the high voltage cell n to the lower plate 16 of the capacitor using the respective second cell switch 10, and connecting the negative terminal of the high voltage cell n to the top plate 12 of the capacitor using the respective first cell switch 6.
  • the switches are closed for a further "on” period as defined above to charge the capacitor further. This so-called “ringing” action is used to remove energy from the cell n and store it in the capacitor 14.
  • the charge stored on the capacitor 14 may then be used to charge the adjacent low voltage cell n-1. This is done by closing the first and second cell switches 6, 28 across the cell n-1 for an "on" period substantially proportional to the resonant frequency of the LC circuit, (with the other cell switches open). Because the voltage of the capacitor 14 is greater than the voltage of the low voltage cell n-1, current will flow from the capacitor via the inductor into the low voltage cell n-1. Due to the nature of the LC circuit some energy will be remain in the capacitor but with reversed voltage polarity.
  • This energy can be transferred to the cell n-1 by reversing the connection of the cell n-1, and by closing the second switch 8 and a further first switch (not shown) to connect the negative side of the cell n-1 to the top plate of the capacitor 14 (via the inductor 20). This is done for a further "on" period substantially proportional to the resonant frequency of the LC circuit.
  • the above sequence of switch operation is repeated until little energy is left stored in the capacitor. hi this way the low voltage cell n-1 is charged to a higher voltage, and the high voltage cell n is discharged, such that the voltages may be equalised. This process may be used for any cell or string of adjacent cells within the string 2.
  • the switches referred to above may comprise any suitable switching circuit.
  • a switching circuit is shown which is suitable for use as any of the first or second cell switches, inductor switch and level shifting switches of the circuit of Figure 1.
  • the switching circuit may for example comprise two N channel mosfet devices 30, 32 which are connected such that they have a common gate 34 and a common source 36 connection.
  • a resistor 38 is connected between the two common terminals 34, 36, and a Zener diode is also connected in parallel with the resistor 38 between the common terminals 34, 36.
  • the control circuit may be arranged to carry out this measuring and equalising process frequently, so as to maintain a relatively constant uniform charge on the cells.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

L'invention concerne un système de gestion de batterie qui utilise un condensateur (14) pour mesurer la charge sur chaque pile d'une chaîne connectée en série et connecte ensuite le condensateur (14) à une pile à tension élevée pour décharger la pile, avant de le connecter à une pile à tension faible pour charger cette pile. De cette façon, une charge sensiblement uniforme sur chaque pile peut être maintenue.
PCT/GB2008/002447 2007-07-20 2008-07-17 Gestion de batterie Ceased WO2009013464A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0714242A GB2451138A (en) 2007-07-20 2007-07-20 Battery cell charge balancing system
GB0714242.5 2007-07-20

Publications (1)

Publication Number Publication Date
WO2009013464A1 true WO2009013464A1 (fr) 2009-01-29

Family

ID=38476743

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2008/002447 Ceased WO2009013464A1 (fr) 2007-07-20 2008-07-17 Gestion de batterie

Country Status (2)

Country Link
GB (1) GB2451138A (fr)
WO (1) WO2009013464A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102074748A (zh) * 2009-11-23 2011-05-25 登丰微电子股份有限公司 电池电压平衡装置及电池充电装置
CN102301560A (zh) * 2009-01-30 2011-12-28 Sk新技术 用于串联连接的电池组的均衡充电设备及方法
WO2012143396A1 (fr) * 2011-04-19 2012-10-26 4Esys Système et procédé d'équilibrage de dispositifs de stockage d'énergie
CN105556794A (zh) * 2013-09-26 2016-05-04 索尼公司 蓄电装置、蓄电控制装置和蓄电控制方法

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US8294421B2 (en) * 2008-09-05 2012-10-23 O2Micro Inc Cell balancing systems employing transformers
JP4691171B2 (ja) * 2009-03-11 2011-06-01 本田技研工業株式会社 充放電装置
US8786255B2 (en) * 2010-05-03 2014-07-22 Infineon Technologies Ag Active charge balancing circuit
JP5576556B2 (ja) * 2011-03-18 2014-08-20 旭化成エレクトロニクス株式会社 直列蓄電セルのバランス充電回路
CN102244477A (zh) * 2011-07-07 2011-11-16 西南交通大学 具有直流电容辅助均压电路的多电平变换器
CN105207476B (zh) * 2015-07-17 2019-10-11 西安交通大学 一种基于电容分压结构的高压直流变压器及其控制方法
CN107482943B (zh) * 2017-07-03 2019-07-30 中国科学院电工研究所 一种多电平变换器直流电容组的均压电路
GB2565334B (en) * 2017-08-10 2020-04-29 Grey Orange Pte Ltd System and method for balancing state of charge of battery
GB2565838B (en) * 2017-08-25 2020-12-23 Ge Aviat Systems Ltd Battery pack balancing system
DE102020204400B4 (de) 2020-04-03 2025-02-06 Volkswagen Aktiengesellschaft Umladevorrichtung, Verfahren zum Betrieb einer Umladevorrichtung und Fahrzeug

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GB2293059A (en) * 1994-09-09 1996-03-13 Ray O Vac Corp Equalization of charge on series connected cells or batteries
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US20070001651A1 (en) * 2004-07-02 2007-01-04 Harvey Troy A Distributed networks of electric double layer capacitor supervisory controllers and networks thereof

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GB2293059A (en) * 1994-09-09 1996-03-13 Ray O Vac Corp Equalization of charge on series connected cells or batteries
US5646534A (en) * 1995-01-06 1997-07-08 Chrysler Corporation Battery monitor for electric vehicles
US5932932A (en) * 1996-09-10 1999-08-03 Honda Giken Kogyo Kabushiki Kaisha Storage battery voltage control apparatus
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102301560A (zh) * 2009-01-30 2011-12-28 Sk新技术 用于串联连接的电池组的均衡充电设备及方法
CN102301560B (zh) * 2009-01-30 2014-01-01 Sk新技术 用于串联连接的电池组的均衡充电设备及方法
US9048669B2 (en) 2009-01-30 2015-06-02 Sk Innovation Co., Ltd. Charge equalization apparatus and method for series-connected battery string
CN102074748A (zh) * 2009-11-23 2011-05-25 登丰微电子股份有限公司 电池电压平衡装置及电池充电装置
WO2012143396A1 (fr) * 2011-04-19 2012-10-26 4Esys Système et procédé d'équilibrage de dispositifs de stockage d'énergie
CN105556794A (zh) * 2013-09-26 2016-05-04 索尼公司 蓄电装置、蓄电控制装置和蓄电控制方法
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EP3051660B1 (fr) * 2013-09-26 2023-01-11 Murata Manufacturing Co., Ltd. Dispositif de stockage d'électricité et procédé de commande de stockage d'électricité

Also Published As

Publication number Publication date
GB2451138A (en) 2009-01-21
GB0714242D0 (en) 2007-08-29

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