(19)
(11)EP 1 864 147 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
03.05.2017 Bulletin 2017/18

(21)Application number: 06732760.1

(22)Date of filing:  31.03.2006
(51)International Patent Classification (IPC): 
G01R 31/36(2006.01)
(86)International application number:
PCT/KR2006/001187
(87)International publication number:
WO 2006/104361 (05.10.2006 Gazette  2006/40)

(54)

APPARATUS AND METHOD FOR MEASURING THE AMOUNT OF THE CURRENT IN BATTERY CELLS USING A PLURALITY OF SENSING RESISTORS

VORRICHTUNG UND VERFAHREN ZUR MESSUNG DER STROMMENGE IN BATTERIEZELLEN UNTER VERWENDUNG MEHRERER MESSWIDERSTÄNDE

APPAREIL ET PROCÉDÉ POUR LA MESURE D'UNE QUANTITÉ DE COURANT DANS DES ÉLÉMENTS D'ACCUMULATEUR UTILISANT UNE PLURALITÉ DE RESISTANCES DE DÉTECTION


(84)Designated Contracting States:
DE FR GB

(30)Priority: 31.03.2005 KR 20050027038

(43)Date of publication of application:
12.12.2007 Bulletin 2007/50

(73)Proprietor: LG Chem, Ltd.
Youngdungpo-gu, Seoul 150-721 (KR)

(72)Inventor:
  • Choi, Jin Ho
    Gyeonggi-do 429-120 (KR)

(74)Representative: Cabinet Plasseraud 
66 rue de la Chaussée d'Antin
75440 Paris Cedex 09
75440 Paris Cedex 09 (FR)


(56)References cited: : 
WO-A-99/27628
JP-A- 09 171 065
US-A- 4 707 795
US-A- 6 014 030
US-B1- 6 285 191
DE-A1- 10 343 179
JP-A- 2002 048 849
US-A- 5 592 095
US-A- 6 014 030
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical Field



    [0001] The present invention relates to an apparatus for measuring an amount of current in battery cells, and more particularly to an apparatus and method for measuring an amount of current in battery cells using multiple detection resistors connecting in parallel a plurality of resistors having a different value of resistance.

    Background Art



    [0002] A conventional method of calculating an amount of current in battery cells has employed a method of detecting and integrating the current in each component using a single fixed detection resistor. This method generates heat due to the use of the single detection resistor, and specifically due to the current in the detection resistor when a long time has lapsed, so that the measurement of the current amount in the battery cells is lowered in precision.

    [0003] A battery pack fuel gauging system using such a single detection resistor will be described with reference to FIG. 1.

    [0004] Referring to FIG. 1, the existing battery pack fuel gauging system 100 comprises battery cells, a resistor 101 for detecting the current from the battery cells, and a main chip 102 detecting and integrating an amount of the detected current.

    [0005] This battery pack fuel gauging system employs a method of detecting the current in the detection resistor 101 at the main chip 102 at constant time intervals, and continuously adding up the current.

    [0006] However, in the method used in the conventional system, increase of the current in the detection resistor 101 during charging or discharging causes an increase in temperature, so that the measurement of the amount of current added up at the main chip 102 is lowered in precision, which has a bad influence on the surrounding components.

    [0007] Thus, there is formed the necessity of preventing damage to the surrounding components caused by the generation of heat of the detection resistor 101 during charging or discharging, and detecting a more precise amount of battery current.

    [0008] US patents 7,707,795 and 6,014,030 and international patent application WO 99/27628 describe different systems for measuring an amount of current in battery cells comprising a plurality of resistors. However, none of these systems remedies the short comings of the system using a single detection resistor described above in terms of heat generation during charging and discharging and precision of the measured amount of battery current.

    Disclosure of the Invention



    [0009] Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an apparatus and method for measuring an amount of current in battery cells, in which a plurality of resistors having a different value of resistance are connected in parallel, the voltage across each resistor is detected, and the amount of current is calculated on the basis of the detected voltage, thereby preventing damage to the surrounding components caused by the generation of heat from the resistor, and detecting a more precise amount of battery current.

    [0010] According to an aspect of the present invention, there is provided an apparatus for measuring an amount of current in battery cells. The apparatus comprises: a plurality of resistors (R1, R2, and R3) connected in parallel; a main chip connected to both ends of one (R1) of the plurality of resistors, detecting voltage across the connected resistor, and adding up the amount of current on the basis of the detected voltage; a multiplexer selecting one of the other resistors (R2 and R3) when the amount of current added up at the main chip exceeds a predetermined threshold value; and a plurality of switches connected to the plurality of resistors respectively, and switched on/off by an output signal of the multiplexer.

    [0011] Here, the plurality of resistors may each have a different value of resistance.

    [0012] Further, the switches may each include Field Effect Transistor (FET) or Bipolar Junction Transistor (BJT).

    [0013] In addition, the multiplexer may include a selection circuit.

    [0014] According to an aspect of the present invention, there is provided a method for measuring an amount of current in battery cells. The method comprises the steps of: detecting voltage across one of a plurality of resistors; adding up the amount of current in the battery cells on the basis of the detected voltage; determining whether or not the added-up amount of current in the battery cells exceeds a predetermined threshold value; when the added-up amount of current in the battery cells exceeds the predetermined threshold value, outputting a control signal to a multiplexer; and switching on, by the multiplexer, a switch connected to one of the resistors other than the detected resistor on the basis of the control signal.

    Brief Description of the Drawings



    [0015] 

    FIG. 1 schematically illustrates a conventional apparatus for measuring an amount of current in battery cells using a detection resistor.

    FIG. 2 illustrates an apparatus for measuring an amount of current in battery cells using a plurality of detection resistors in accordance with an embodiment of the present invention.

    FIG. 3 illustrates a method for measuring an amount of current in battery cells using a plurality of detection resistors in accordance with an embodiment of the present invention.


    Mode for Carrying Out the Invention



    [0016] Reference will now be made in detail to the preferred embodiments of the present invention.

    [0017] FIG. 2 illustrates an apparatus 200 for measuring an amount of current in battery cells using a plurality of detection resistors in accordance with an embodiment of the present invention.

    [0018] Referring to FIG. 2, the apparatus 200 for measuring an amount of current in battery cells in accordance with an embodiment of the present invention comprises a plurality of resistors R1, R2, and R3 for detecting the current from the battery cells, a main chip 201 adding up the detected amount of current, a plurality of switches S1, S2, and S3 connected to the plurality of resistors respectively, and a multiplexer (MUX) 202 switching on/off the switches based on a control signal of the main chip 201.

    [0019] In the apparatus 200 for measuring an amount of current in battery cells in accordance with the present invention, the current flows from battery cells C1, C2, C3, and C4 to the plurality of resistors R1, R2, and R3. The battery cells C1, C2, C3, and C4 are connected in parallel with the plurality of resistors R1, R2, and R3. In this manner, because the battery cells are connected in parallel with the plurality of resistors, the current from the battery cells can be distributed to each resistor. Each of the resistors has a different value of resistance.

    [0020] First, the current from the battery cells C1, C2, C3, and C4 flows through one R1 of the plurality of resistors. The main chip 201 detects the voltage across the resistor R1, and adds up it as an amount of current. The amount of current added up reaches a predetermined threshold value with the lapse of time.

    [0021] When the amount of current detected at the resistor R1 reaches the predetermined threshold value, the main chip 201 instructs the MUX 202 to switch on the switch S2 of the resistor R2. On the basis of the instruction of the main chip 201, the MUX 202 switches on the switch S2, which is connected to the resistor R2. Further, MUX 202 can be constructed as a selection circuit.

    [0022] Accordingly, the current from the battery cells C1, C2, C3, and C4 is distributed and flows through the resistors R1 and R2. The main chip 201 detects the voltage across each of the resistors R1 and R2, and adds up each amount of current. Likewise, the amount of current added up reaches a predetermined threshold value with the lapse of time.

    [0023] When the amount of current detected at the resistors R1 and R2 reaches the predetermined threshold value, the main chip 201 instructs the MUX 202 to switch on the switch of the resistor R3. On the basis of the instruction of the main chip 201, the MUX 202 switches on the switch S3, which is connected to the resistor R3. The switches S1, S2, and S3 can be formed from Field Effect Transistor (FET) and Bipolar Junction Transistor (BJT).

    [0024] In this manner, the existing problems on the generation of heat when the amount of current of the battery cells is measured using a single detection resistor can be solved by distributing the current from the battery cells using the plurality of detection resistors.

    [0025] Therefore, the apparatus for measuring the amount of current in the battery cells in accordance with the present invention can not only prevent damage to the surrounding components caused by the generation of heat from the single detection resistor, but also detect a more precise amount of current in the battery cells.

    [0026] On the basis of this construction, a method for measuring the amount of current in the battery cells will be described with reference to FIG. 3.

    [0027] Referring to FIG. 3, in step S301, the voltage across one of the resistors from the battery cells is detected at the main chip 201.

    [0028] In step S302, on the basis of the detected voltage across the resistor, an amount of battery current is added up at the main chip 201.

    [0029] In step S303, it is continuously determined whether or not the amount of current added up at the main chip 201 exceeds a predetermined threshold value.

    [0030] In step S304, if the amount of current added up at the main chip 201 exceeds the predetermined threshold value, a control signal is output to the MUX 202. In contrast, if the amount of current added up at the main chip 201 does not exceed the predetermined threshold value, the process returns to step S301.

    [0031] In step S305, on the basis of the control signal of the main chip 201, the MUX 202 switches on the switches connected to resistors other than the detected resistor, and then the process is ended.

    Industrial Applicability



    [0032] With the configuration of the apparatus and method for measuring the amount of current in the battery cells, the plurality of resistors having different values of resistance are connected in parallel, and the current in the resistors is distributed. Thereby, it is possible to not only prevent damage to the surrounding components caused by the generation of heat from the resistor, but also detect a more precise amount of battery current.


    Claims

    1. An apparatus for measuring an amount of current in battery cells, the apparatus comprising:

    - a plurality of resistors (R1, R2, and R3) for detecting the current from the battery cells, said resistors being connected in parallel and installed on the current flow line connected to the battery cells;

    - a main chip (201) adding up the detected amount of current;

    - a plurality of switches (S1, S2, S3) connected to the plurality of resistors respectively; and

    - a multiplexer (202) switching on/off the switches based on a control signal of the main chip (201),

    - a multiplexer outputting a switching signal to each of the plurality of switches (S1, S2, S3)

    characterized in that
    the main chip (201) is connected to both ends of each of the plurality of resistors (R1, R2, R3) and detects voltage across the connected resistors.
     
    2. The apparatus according to claim 1, wherein the plurality of resistor each have a different value of resistance.
     
    3. The apparatus according to claim 1, wherein the switches are each composed of Field Effect Transistor (FET) or Bipolar Junction Transistor (BJT).
     
    4. The apparatus according to claim 1, wherein the multiplexer includes a selection circuit.
     
    5. A method for measuring an amount of current in battery cells, the method comprising the steps of:

    detecting voltage across one (R1) of a plurality of resistors (R1, R2, R3) connected in parallel;

    adding up the amount of current in the battery cells on the basis of the detected voltage;

    determining whether or not the added-up amount of current in the battery cells exceeds a predetermined threshold value;

    When the added-up amount of current in the battery cells exceeds the predetermined threshold value, outputting a control signal to multiplexer (202); and

    switching on, by the multiplexer (202), a switch connected to one of the resistors (R2, R3) other than the detected resistor (R1) on the basis of the control signal.


     
    6. The method according to claim 5, wherein the determining step includes returning to the voltage detecting step when the added-up amount of current in the battery cells does not exceed the predetermined threshold value.
     


    Ansprüche

    1. Vorrichtung zum Messen einer Menge an Strom in Batteriezellen, wobei die Vorrichtung umfasst:

    - eine Mehrzahl von Widerständen (R1, R2, und R3) zum Detektieren des Stroms aus den Batteriezellen, wobei die Widerstände parallelgeschaltet sind und an der mit den Batteriezellen verbundenen Stromflussleitung installiert sind;

    - einen Hauptchip (201), welcher die detektierten Mengen an Strom aufaddiert;

    - eine Mehrzahl von Schaltern (S1, S2, S3), jeweils mit der Mehrzahl von Widerständen verbunden; und

    - einen Multiplexer (202), welcher die Schalter basierend auf einem Regel-/Steuersignal des Hauptchips (201) an-/ausschaltet,

    - einen Multiplexer, welcher ein Schaltsignal zu jedem aus der Mehrzahl von Schaltern (S1, S2, S3) ausgibt,

    dadurch gekennzeichnet, dass
    der Hauptchip (201) mit beiden Enden von jedem aus der Mehrzahl von Widerständen (R1, R2, R3) verbunden ist und eine Spannung über die verbundenen Widerstände detektiert.
     
    2. Vorrichtung nach Anspruch 1, wobei in der Mehrzahl von Widerständen jeder Widerstand einen unterschiedlichen Widerstandswert aufweist.
     
    3. Vorrichtung nach Anspruch 1, wobei die Schalter jeweils aus einem Feldeffekttransistor (FET) oder einem Bipolartransistor (BJT) zusammengesetzt sind.
     
    4. Vorrichtung nach Anspruch 1, wobei der Multiplexer eine Auswahlschaltung enthält.
     
    5. Verfahren zum Messen einer Menge an Strom in Batteriezellen, wobei das Verfahren die Schritte umfasst:

    Detektieren einer Spannung über einen (R1) aus einer Mehrzahl von parallel geschalteten Widerständen (R1, R2, R3);

    Aufaddieren der Menge an Strom in den Batteriezellen auf der Basis der detektierten Spannung;

    Bestimmen, ob oder ob nicht die aufaddierte Menge an Strom in den Batteriezellen einen vorbestimmten Schwellenwert überschreitet;

    wenn die aufaddierte Menge an Strom in den Batteriezellen den vorbestimmten Schwellenwert überschreitet, Ausgeben eines Regel-/Steuersignals an einen Multiplexer (202); und

    Einschalten, durch den Multiplexer (202), eines Schalters, welcher mit einem der Widerstände (R2, R3) verbunden ist, welcher von dem detektierten Widerstand (R1) unterschiedlich ist, auf der Basis des Regel-/Steuersignals.


     
    6. Verfahren nach Anspruch 5, wobei der Bestimmungsschritt eine Rückkehr zu dem Spannungsdetektionsschritt enthält, wenn die aufaddierte Menge an Strom in den Batteriezellen nicht den vorbestimmten Schwellenwert überschreitet.
     


    Revendications

    1. Appareil pour mesurer une quantité de courant dans des cellules de batterie, l'appareil comprenant :

    - une pluralité de résistances (R1, R2, et R3) pour détecter le courant provenant des cellules de batterie, lesdites résistances étant connectées en parallèle et installées sur la ligne de flux de courant connectée aux cellules de batterie ;

    - une puce principale (201) additionnant la quantité de courant détectée ;

    - une pluralité de commutateurs (S1, S2, S3) connectés à la pluralité de résistances respectivement ; et

    - un multiplexeur (202) allumant/éteignant les commutateurs en fonction d'un signal de commande de la puce principale (201),

    - un multiplexeur émettant un signal de commutation à chacun parmi la pluralité de commutateurs (S1, S2, S3),

    caractérisé en ce que
    la puce principale (201) est connectée aux deux extrémités de chacune parmi la pluralité de résistances (R1, R2, R3) et détecte une tension sur les résistances connectées.
     
    2. Appareil selon la revendication 1, dans lequel chacune parmi la pluralité de résistances possède une valeur de résistance différente.
     
    3. Appareil selon la revendication 1, dans lequel les commutateurs sont chacun composés de transistor à effet de champ (FET) ou de transistor à jonctions bipolaires (BJT).
     
    4. Appareil selon la revendication 1, dans lequel le multiplexeur inclut un circuit de sélection.
     
    5. Procédé pour mesurer une quantité de courant dans des cellules de batterie, le procédé comprenant les étapes de :

    détection d'une tension sur l'une (R1) parmi une pluralité de résistances (R1, R2, R3) connectées en parallèle ;

    addition de la quantité de courant, dans les cellules de batterie, en fonction de la tension détectée ;

    détermination que la quantité de courant additionnée, dans les cellules de batterie, dépasse ou non une valeur de seuil prédéterminée ;

    lorsque la quantité de courant additionnée, dans les cellules de batterie, dépasse la valeur de seuil prédéterminée, émission d'un signal de commande à un multiplexeur (202) ; et

    allumage, par le multiplexeur (202), d'un commutateur connecté à l'une des résistances (R2, R3), autre que la résistance détectée (R1), en fonction du signal de commande.


     
    6. Procédé selon la revendication 5, dans lequel l'étape de détermination inclut le retour à l'étape de détection de tension lorsque la quantité de courant additionnée, dans les cellules de batterie, ne dépasse pas la valeur de seuil prédéterminée.
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description