JP2017156244A

JP2017156244A - Battery voltage detector

Info

Publication number: JP2017156244A
Application number: JP2016040350A
Authority: JP
Inventors: 肥田　実; Minoru Hida; 実肥田
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2016-03-02
Filing date: 2016-03-02
Publication date: 2017-09-07
Anticipated expiration: 2036-03-02
Also published as: JP6593226B2

Abstract

PROBLEM TO BE SOLVED: To ensure that the cell voltages of a plurality of cells connected in series do not significantly vary between each cell.SOLUTION: Provided is a battery voltage detector including a plurality of cells connected in series and also including for each cell a differential amplification circuit operating on the basis of the potential of a lowest order detection line as a point of reference that is connected to the negative pole of a lowest order cell whose potential is lowest among the plurality of cells, and differentially amplifying the cell voltage of a corresponding cell among the plurality of cells. A connection point between adjacent cells among the plurality of cells is connected, via an intercell detection line connected to the connection point, to a differential amplification circuit for differentially amplifying the cell voltage of a cell out of the adjacent cells whose potential is lower and a differential amplification circuit for differentially amplifying the cell voltage of a cell out of the adjacent cells whose potential is higher. A resistive element for pulling up the intercell detection line to a highest order detection line connected to the positive pole of a highest order cell whose potential is highest among the plurality of cells is provided for each intercell detection line.SELECTED DRAWING: Figure 1

Description

本発明は、電池電圧検出装置に関する。 The present invention relates to a battery voltage detection device.

従来、直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える、電池電圧検出装置が知られている（例えば、特許文献１参照）。 2. Description of the Related Art Conventionally, a battery voltage detection device is known that includes a differential amplifier circuit for differentially amplifying a cell voltage of a corresponding cell among a plurality of cells connected in series (see, for example, Patent Document 1). .

特開２０１２−４７５２０公報JP 2012-47520 A

しかしながら、セル毎に備えられた各差動増幅回路が、直列に接続された複数のセルのうち最も電位の低いセルの負極に接続された検出線の電位を基準に動作する構成であると、セルから放電される放電電流は電位の低いセルほど大きくなる場合がある。この場合、セル電圧が各セル間でばらつき易くなる。 However, each differential amplifier circuit provided for each cell is configured to operate based on the potential of the detection line connected to the negative electrode of the cell having the lowest potential among the plurality of cells connected in series. The discharge current discharged from the cell may become larger as the cell has a lower potential. In this case, the cell voltage tends to vary from cell to cell.

例えば、図１は、直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置の一比較例を示す図である。図１に示された電池電圧検出装置１は、４つのセル１１〜１４のうち最も電位の低い最下位セル１１の負極に接続された最下位検出線３０の電位４１を基準に動作する４つの差動増幅回路２１〜２４を備える。差動増幅回路２１〜２４は、それぞれ、セル１１〜１４のうち対応するセルのセル電圧を差動増幅する。 For example, FIG. 1 is a diagram illustrating a comparative example of a battery voltage detection device including a differential amplifier circuit for each cell that differentially amplifies a cell voltage of a corresponding cell among a plurality of cells connected in series. The battery voltage detection apparatus 1 shown in FIG. 1 operates on the basis of the potential 41 of the lowest detection line 30 connected to the negative electrode of the lowest cell 11 having the lowest potential among the four cells 11 to 14. Differential amplifier circuits 21 to 24 are provided. The differential amplifier circuits 21 to 24 differentially amplify the cell voltages of the corresponding cells among the cells 11 to 14, respectively.

隣り合うセル１１，１２間の接続点５１は、接続点５１に接続されたセル間検出線３１を介して、セル１１のセル電圧を差動増幅する差動増幅回路２１とセル１２のセル電圧を差動増幅する差動増幅回路２２とに接続されている。差動増幅回路２１，２２は共通の電位４１を基準に動作するため、接続点５１からセル間検出線３１に流れ出る電流５１ａは、差動増幅回路２１，２２を経由して、最下位セル１１の負極に流れ込む。つまり、電流５１ａには、セル１１から放電される電流が含まれている。 The connection point 51 between the adjacent cells 11 and 12 is connected to the differential amplification circuit 21 that differentially amplifies the cell voltage of the cell 11 via the inter-cell detection line 31 connected to the connection point 51 and the cell voltage of the cell 12. Is connected to a differential amplifier circuit 22 that differentially amplifies the signal. Since the differential amplifier circuits 21 and 22 operate on the basis of the common potential 41, the current 51a flowing out from the connection point 51 to the inter-cell detection line 31 passes through the differential amplifier circuits 21 and 22 and the lowest cell 11 Flows into the negative electrode. That is, the current 51a includes a current discharged from the cell 11.

同様に、隣り合うセル１２，１３間の接続点５２は、接続点５２に接続されたセル間検出線３２を介して、セル１２のセル電圧を差動増幅する差動増幅回路２２とセル１３のセル電圧を差動増幅する差動増幅回路２３とに接続されている。差動増幅回路２２，２３は共通の電位４１を基準に動作するため、接続点５２からセル間検出線３２に流れ出る電流５２ａは、差動増幅回路２２，２３を経由して、最下位セル１１の負極に流れ込む。つまり、電流５２ａには、セル１１とセル１２とから放電される電流が含まれている。 Similarly, the connection point 52 between the adjacent cells 12 and 13 is connected to the differential amplifier circuit 22 and the cell 13 which differentially amplifies the cell voltage of the cell 12 via the inter-cell detection line 32 connected to the connection point 52. Are connected to a differential amplifier circuit 23 for differentially amplifying the cell voltage. Since the differential amplifier circuits 22 and 23 operate based on the common potential 41, the current 52 a flowing out from the connection point 52 to the inter-cell detection line 32 passes through the differential amplifier circuits 22 and 23 and the lowest cell 11. Flows into the negative electrode. That is, the current 52a includes a current discharged from the cell 11 and the cell 12.

隣り合うセル１３，１４間の接続点５３からセル間検出線３３に流れ出る電流５３ａについても上記同様に考えることができるので、電流５３ａには、セル１１とセル１２とセル１３とから放電される電流が含まれている。 Since the current 53a flowing out from the connection point 53 between the adjacent cells 13 and 14 to the inter-cell detection line 33 can be considered in the same manner as described above, the current 53a is discharged from the cell 11, the cell 12 and the cell 13. Current is included.

このように、電流５１ａ，５２ａ，５３ａのそれぞれに含まれる電流を放電するセルに着目すると、セルから放電される総放電量は、直列に接続された複数のセルのうち電位の低いセルほど大きいので、セル電圧が各セル間でばらつき易い。 Thus, when attention is paid to the cells that discharge the currents included in each of the currents 51a, 52a, and 53a, the total discharge amount discharged from the cells is larger in the cells having a lower potential among the plurality of cells connected in series. Therefore, the cell voltage tends to vary between cells.

そこで、本発明の一態様は、直列に接続された複数のセルのセル電圧を各セル間でばらつき難くすることを目的とする。 In view of the above, an object of one embodiment of the present invention is to make the cell voltages of a plurality of cells connected in series difficult to vary among cells.

上記目的を達成するためには、隣り合うセル間の接続点からセル間検出線に流れ出る電流をセル間検出線毎に低減することができればよい。 In order to achieve the above object, it is sufficient that the current flowing out from the connection point between adjacent cells to the inter-cell detection line can be reduced for each inter-cell detection line.

そこで、本発明の一態様では、
直列に接続された複数のセルを備えるとともに、
前記複数のセルのうち最も電位の低い最下位セルの負極に接続された最下位検出線の電位を基準に動作し、前記複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備え、
前記複数のセルのうちで隣り合うセル間の接続点は、前記接続点に接続されたセル間検出線を介して、前記隣り合うセルの電位の低い方のセルのセル電圧を差動増幅する差動増幅回路と前記隣り合うセルの電位の高い方のセルのセル電圧を差動増幅する差動増幅回路とに接続された、電池電圧検出装置であって、
前記複数のセルのうち最も電位の高い最上位セルの正極に接続された最上位検出線に前記セル間検出線をプルアップする抵抗素子を前記セル間検出線毎に備える、電池電圧検出装置が提供される。 Therefore, in one embodiment of the present invention,
With a plurality of cells connected in series,
A differential that operates based on the potential of the lowest detection line connected to the negative electrode of the lowest cell having the lowest potential among the plurality of cells, and differentially amplifies the cell voltage of the corresponding cell among the plurality of cells. Amplifying circuit is provided for each cell,
A connection point between adjacent cells among the plurality of cells differentially amplifies a cell voltage of a cell having a lower potential of the adjacent cell via an inter-cell detection line connected to the connection point. A battery voltage detection device connected to a differential amplifier circuit and a differential amplifier circuit that differentially amplifies the cell voltage of the higher potential cell of the adjacent cell,
A battery voltage detection device comprising a resistance element for pulling up the inter-cell detection line to the uppermost detection line connected to the positive electrode of the highest cell having the highest potential among the plurality of cells. Provided.

本態様によれば、前記最上位検出線から前記抵抗素子を経由して前記セル間検出線に電流を流し出すことができるので、隣り合うセルの接続点からセル間検出線に流れ出る電流を低減することができる。そして、そのような前記抵抗素子がセル間検出線毎に備えられていることにより、隣り合うセル間の接続点からセル間検出線に流れ出る電流をセル間検出線毎に低減させることができる。セル間検出線に流れ出る電流をセル間検出線毎に低減することにより、前記最上位セルを経由して前記最上位検出線に流れ出る電流が増加する。その結果、各セルの総放電量は均等に近づくので、セル電圧が各セル間でばらつき難くなる。 According to this aspect, since the current can flow out from the uppermost detection line to the inter-cell detection line via the resistance element, the current flowing out from the connection point of adjacent cells to the inter-cell detection line is reduced. can do. And since the said resistive element is provided for every detection line between cells, the electric current which flows into the detection line between cells from the connection point between adjacent cells can be reduced for every detection line between cells. By reducing the current flowing to the inter-cell detection line for each inter-cell detection line, the current flowing to the uppermost detection line via the uppermost cell increases. As a result, the total discharge amount of each cell approaches evenly, so that the cell voltage is less likely to vary between cells.

本発明の一態様によれば、直列に接続された複数のセルのセル電圧が各セル間でばらつき難くなる。 According to one embodiment of the present invention, the cell voltages of a plurality of cells connected in series are less likely to vary between cells.

直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置の一比較例を示す図である。It is a figure which shows the comparative example of the battery voltage detection apparatus provided with the differential amplifier circuit for differentially amplifying the cell voltage of a corresponding cell among the several cells connected in series for every cell. 直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置の一実施例を示す図である。It is a figure which shows one Example of a battery voltage detection apparatus provided with the differential amplifier circuit for differentially amplifying the cell voltage of a corresponding cell among several cells connected in series for every cell. 直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置の一具体例を示す図である。It is a figure which shows one specific example of the battery voltage detection apparatus provided with the differential amplifier circuit for differentially amplifying the cell voltage of a corresponding cell among the several cells connected in series for every cell. 直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置の他の一具体例を示す図である。It is a figure which shows another specific example of the battery voltage detection apparatus provided with the differential amplifier circuit for differentially amplifying the cell voltage of a corresponding cell among the several cells connected in series for every cell.

図２は、直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置の一実施例を示す図である。図２に示される電池電圧検出装置２は、直列に接続された４つのセル６１〜６４を含む組電池６０と、セルと同数の４つの差動増幅回路７１〜７４とを備える。 FIG. 2 is a diagram illustrating an embodiment of a battery voltage detection device including, for each cell, a differential amplifier circuit that differentially amplifies the cell voltage of a corresponding cell among a plurality of cells connected in series. The battery voltage detection device 2 shown in FIG. 2 includes a battery pack 60 including four cells 61 to 64 connected in series, and four differential amplifier circuits 71 to 74 as many as the cells.

差動増幅回路７１は、一対の検出線８０，８１を介して並列に接続されたセル６１のセル電圧を検出する。差動増幅回路７２は、一対の検出線８１，８２を介して並列に接続されたセル６２のセル電圧を検出する。差動増幅回路７３は、一対の検出線８２，８３を介して並列に接続されたセル６３のセル電圧を検出する。差動増幅回路７４は、一対の検出線８３，８４を介して並列に接続されたセル６４のセル電圧を検出する。セルのセル電圧とは、そのセルの両極間の電圧である。 The differential amplifier circuit 71 detects the cell voltage of the cells 61 connected in parallel via a pair of detection lines 80 and 81. The differential amplifier circuit 72 detects the cell voltage of the cells 62 connected in parallel via the pair of detection lines 81 and 82. The differential amplifier circuit 73 detects the cell voltage of the cells 63 connected in parallel via the pair of detection lines 82 and 83. The differential amplifier circuit 74 detects the cell voltage of the cells 64 connected in parallel via the pair of detection lines 83 and 84. The cell voltage of a cell is the voltage between both poles of the cell.

差動増幅回路７１〜７４は、それぞれ、４つのセル６１〜６４のうち最も電位の低い最下位セル６１の負極に接続された最下位検出線８０の電位４２（グランド電位）を基準に動作する。差動増幅回路７１〜７４は、それぞれ、セル６１〜６４のうち対応するセルのセル電圧を電位４２を基準に差動増幅し、電位４２を基準とした差動増幅後の電圧を出力する。 The differential amplifier circuits 71 to 74 operate on the basis of the potential 42 (ground potential) of the lowest detection line 80 connected to the negative electrode of the lowest cell 61 having the lowest potential among the four cells 61 to 64. . Each of the differential amplifier circuits 71 to 74 differentially amplifies the cell voltage of the corresponding cell among the cells 61 to 64 with reference to the potential 42, and outputs a voltage after differential amplification based on the potential 42.

隣り合うセル６１，６２間の接続点９１は、接続点９１に接続されたセル間検出線８１を介して、セル６１のセル電圧を差動増幅する差動増幅回路７１とセル６２のセル電圧を差動増幅する差動増幅回路７２とに接続されている。接続点９１は、隣り合うセル６１，６２のうち電位の低い方のセル６１の正極と電位の高い方のセル６２の負極とが接続されたノードである。 The connection point 91 between the adjacent cells 61 and 62 is connected to the differential amplification circuit 71 that differentially amplifies the cell voltage of the cell 61 and the cell voltage of the cell 62 via the inter-cell detection line 81 connected to the connection point 91. Is connected to a differential amplifier circuit 72 for differentially amplifying the signal. The connection point 91 is a node where the positive electrode of the cell 61 having the lower potential and the negative electrode of the cell 62 having the higher potential are connected to each other among the adjacent cells 61 and 62.

差動増幅回路７１，７２は共通の電位４２を基準に動作するため、接続点９１からセル間検出線８１に流れ出る電流９１ａは、差動増幅回路７１，７２を経由して、最下位セル６１の負極に流れ込む。つまり、電流９１ａには、セル６１から放電される電流が含まれている。 Since the differential amplifier circuits 71 and 72 operate on the basis of the common potential 42, the current 91 a flowing out from the connection point 91 to the inter-cell detection line 81 passes through the differential amplifier circuits 71 and 72 and the lowest cell 61. Flows into the negative electrode. That is, the current 91a includes a current discharged from the cell 61.

隣り合うセル６２，６３間の接続点９２は、接続点９２に接続されたセル間検出線８２を介して、セル６２のセル電圧を差動増幅する差動増幅回路７２とセル６３のセル電圧を差動増幅する差動増幅回路７３とに接続されている。接続点９２は、隣り合うセル６２，６３のうち電位の低い方のセル６２の正極と電位の高い方のセル６３の負極とが接続されたノードである。 A connection point 92 between the adjacent cells 62 and 63 is connected to a differential amplification circuit 72 that differentially amplifies the cell voltage of the cell 62 and a cell voltage of the cell 63 via an inter-cell detection line 82 connected to the connection point 92. Is connected to a differential amplifier circuit 73 that differentially amplifies the signal. The connection point 92 is a node where the positive electrode of the cell 62 having the lower potential and the negative electrode of the cell 63 having the higher potential are connected to each other among the adjacent cells 62 and 63.

差動増幅回路７２，７３は共通の電位４２を基準に動作するため、接続点９２からセル間検出線８２に流れ出る電流９２ａは、差動増幅回路７２，７３を経由して、最下位セル６１の負極に流れ込む。つまり、電流９２ａには、セル６１とセル６２とから放電される電流が含まれている。 Since the differential amplifier circuits 72 and 73 operate on the basis of the common potential 42, the current 92 a flowing out from the connection point 92 to the inter-cell detection line 82 passes through the differential amplifier circuits 72 and 73 and the lowest cell 61. Flows into the negative electrode. That is, the current 92a includes a current discharged from the cell 61 and the cell 62.

隣り合うセル６３，６４間の接続点９３は、接続点９３に接続されたセル間検出線８３を介して、セル６３のセル電圧を差動増幅する差動増幅回路７３とセル６４のセル電圧を差動増幅する差動増幅回路７４とに接続されている。接続点９３は、隣り合うセル６３，６４のうち電位の低い方のセル６３の正極と電位の高い方のセル６４の負極とが接続されたノードである。 A connection point 93 between adjacent cells 63 and 64 is connected to a differential amplifier circuit 73 for differentially amplifying the cell voltage of the cell 63 and a cell voltage of the cell 64 via an inter-cell detection line 83 connected to the connection point 93. Is connected to a differential amplifier circuit 74 that differentially amplifies the signal. The connection point 93 is a node where the positive electrode of the cell 63 having a lower potential and the negative electrode of the cell 64 having a higher potential are connected to each other among the adjacent cells 63 and 64.

差動増幅回路７３，７４は共通の電位４２を基準に動作するため、接続点９３からセル間検出線８３に流れ出る電流９３ａは、差動増幅回路７３，７４を経由して、最下位セル６１の負極に流れ込む。つまり、電流９３ａには、セル６１とセル６２とセル６３とから放電される電流が含まれている。 Since the differential amplifier circuits 73 and 74 operate based on the common potential 42, the current 93 a flowing out from the connection point 93 to the inter-cell detection line 83 passes through the differential amplifier circuits 73 and 74, and the lowest cell 61. Flows into the negative electrode. That is, the current 93a includes a current discharged from the cell 61, the cell 62, and the cell 63.

電池電圧検出装置２は、セル６１〜６４のうち最も電位の高い最上位セル６４の正極に接続された最上位検出線８４にセル間検出線をプルアップする抵抗素子をセル間検出線毎に備える。抵抗素子は、抵抗成分を有する素子である。電池電圧検出装置２は、３つの抵抗素子１０１〜１０３を備える。抵抗素子１０１は、最上位検出線８４にセル間検出線８１をプルアップする。抵抗素子１０２は、最上位検出線８４にセル間検出線８２をプルアップする。抵抗素子１０３は、最上位検出線８４にセル間検出線８３をプルアップする。 The battery voltage detection device 2 includes, for each inter-cell detection line, a resistance element that pulls up the inter-cell detection line to the uppermost detection line 84 connected to the positive electrode of the uppermost cell 64 having the highest potential among the cells 61 to 64. Prepare. The resistance element is an element having a resistance component. The battery voltage detection device 2 includes three resistance elements 101 to 103. The resistance element 101 pulls up the inter-cell detection line 81 to the uppermost detection line 84. The resistance element 102 pulls up the inter-cell detection line 82 to the uppermost detection line 84. The resistance element 103 pulls up the inter-cell detection line 83 to the uppermost detection line 84.

このように、セル間検出線８１と最上位検出線８４とが抵抗素子１０１を介して接続されることにより、最上位検出線８４から抵抗素子１０１を経由してセル間検出線８１に電流１０１ａを流し出すことができる。電流１０１ａがセル間検出線８１に流し出される分だけ、接続点９１からセル間検出線８１に流れ出る電流９１ａを低減することができる。 As described above, the inter-cell detection line 81 and the uppermost detection line 84 are connected via the resistance element 101, whereby the current 101 a flows from the uppermost detection line 84 to the inter-cell detection line 81 via the resistance element 101. Can be washed out. The current 91 a flowing out from the connection point 91 to the inter-cell detection line 81 can be reduced by the amount that the current 101 a flows out to the inter-cell detection line 81.

同様に、最上位検出線８４から抵抗素子１０２を経由してセル間検出線８２に電流１０２ａを流し出すことができるので、電流１０２ａがセル間検出線８２に流し出される分だけ、接続点９２からセル間検出線８２に流れ出る電流９２ａを低減することができる。同様に、最上位検出線８４から抵抗素子１０３を経由してセル間検出線８３に電流１０３ａを流し出すことができる。電流１０３ａがセル間検出線８３に流し出される分だけ、接続点９３からセル間検出線８３に流れ出る電流９３ａを低減することができる。 Similarly, since the current 102a can flow from the uppermost detection line 84 to the inter-cell detection line 82 via the resistance element 102, the connection point 92 is equivalent to the amount that the current 102a flows to the inter-cell detection line 82. The current 92a flowing out from the cell to the inter-cell detection line 82 can be reduced. Similarly, the current 103 a can flow from the uppermost detection line 84 to the inter-cell detection line 83 via the resistance element 103. The current 93a flowing out from the connection point 93 to the inter-cell detection line 83 can be reduced by the amount that the current 103a flows out to the inter-cell detection line 83.

このように、セル間検出線に流れ出る電流９１ａ，９２ａ，９３ａのそれぞれが低減することにより、最上位セル６４を経由して最上位検出線８４に流れ出る電流が増加する。その結果、各セル６１〜６４の総放電量は均等に近づくので、セル電圧が各セル６１〜６４間でばらつき難くなる。 As described above, each of the currents 91a, 92a, and 93a flowing out to the inter-cell detection line is reduced, so that the current flowing out to the uppermost detection line 84 via the uppermost cell 64 is increased. As a result, the total discharge amount of each of the cells 61 to 64 approaches evenly, so that the cell voltage is less likely to vary between the cells 61 to 64.

また、抵抗素子１０１〜１０３は、いずれも、セル間検出線を最上位検出線８４にプルアップするため、抵抗素子１０１〜１０３のうち電位の低いセル間検出線をプルアップする素子ほど印加電圧が高い。例えば、抵抗素子１０１には、セル６２〜６４までの各セルのセル電圧を足した総セル電圧が印加されるが、抵抗素子１０３には、セル６４のセル電圧が印加される。 In addition, since each of the resistance elements 101 to 103 pulls up the inter-cell detection line to the uppermost detection line 84, the applied voltage increases as the element pulls up the inter-cell detection line having a lower potential among the resistance elements 101 to 103. Is expensive. For example, the total cell voltage obtained by adding the cell voltages of the cells 62 to 64 is applied to the resistance element 101, while the cell voltage of the cell 64 is applied to the resistance element 103.

そこで、抵抗素子１０１〜１０３のうち電位の低いセル間検出線をプルアップする素子ほど抵抗値が高く設定されることが好適である。つまり、抵抗素子１０１の抵抗値は、抵抗素子１０２の抵抗値よりも高く、抵抗素子１０２の抵抗値は、抵抗素子１０３の抵抗値よりも高い。このような大小関係で各抵抗素子の抵抗値が設定されることにより、隣り合うセル間の接続点から流し出される電流と抵抗素子を経由して流し出される電流との相殺がし易くなる。したがって、電流９１ａ，９２ａ，９３ａをいずれも零まで低減し易くなるので、セル電圧を各セル６１〜６４間で一層ばらつき難くすることができる。 Therefore, it is preferable that the resistance value is set higher for the element that pulls up the inter-cell detection line having a lower potential among the resistance elements 101 to 103. That is, the resistance value of the resistance element 101 is higher than the resistance value of the resistance element 102, and the resistance value of the resistance element 102 is higher than the resistance value of the resistance element 103. By setting the resistance value of each resistance element in such a magnitude relationship, it becomes easy to cancel the current flowing out from the connection point between adjacent cells and the current flowing out through the resistance element. Therefore, the currents 91a, 92a, and 93a can all be easily reduced to zero, so that the cell voltage can be made more difficult to vary between the cells 61 to 64.

図３は、直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置３の一具体例を示す図である。図３には、差動増幅回路７１〜７４の具体例が例示されている。 FIG. 3 is a diagram illustrating a specific example of the battery voltage detection device 3 including, for each cell, a differential amplifier circuit that differentially amplifies a cell voltage of a corresponding cell among a plurality of cells connected in series. FIG. 3 illustrates a specific example of the differential amplifier circuits 71 to 74.

差動増幅回路７０は、それぞれ、最も電位の低い最下位セルの負極に接続された最下位検出線１２０の電位４４（グランド電位）を基準に動作する。差動増幅回路７０は、それぞれ、直列に接続された複数のセルのうち対応するセルのセル電圧を電位４４を基準に差動増幅し、電位４４を基準とした差動増幅後の電圧を出力する。 Each of the differential amplifier circuits 70 operates based on the potential 44 (ground potential) of the lowest detection line 120 connected to the negative electrode of the lowest cell having the lowest potential. The differential amplifier circuit 70 differentially amplifies the cell voltage of the corresponding cell among a plurality of cells connected in series with respect to the potential 44, and outputs the voltage after differential amplification with the potential 44 as a reference. To do.

図３に例示された差動増幅回路７０は、それぞれ、同一の回路構成を有する。差動増幅回路７０は、それぞれ、オペアンプ１１１と、抵抗体１１２〜１１５とを有する。抵抗体は、抵抗成分を有する素子である。 The differential amplifier circuits 70 illustrated in FIG. 3 each have the same circuit configuration. Each of the differential amplifier circuits 70 includes an operational amplifier 111 and resistors 112 to 115. The resistor is an element having a resistance component.

オペアンプ１１１の電源電圧は、最も電位の高い最上位セルの正極に接続された最上位検出線１３０の電位４３（電源電位）と、最も電位の低い最下位セルの負極に接続された最下位検出線１２０の電位４４（グランド電位）との間の電圧である。オペアンプ１１１の非反転入力端子は、抵抗体１１２を介して、セルの正極に一端が接続された検出線の他端に接続され、オペアンプ１１１の反転入力端子は、抵抗体１１３を介して、当該セルの負極に一端が接続された検出線の他端に接続されている。抵抗体１１２とオペアンプ１１１の非反転入力端子との間のノードは、抵抗体１１４を介して、電位４４に接続され、抵抗体１１３とオペアンプ１１１の反転入力端子との間のノードは、抵抗体１１５を介して、差動増幅回路７０の出力端子（オペアンプ１１１の出力端子）に接続されている。 The power supply voltage of the operational amplifier 111 includes the potential 43 (power supply potential) of the highest detection line 130 connected to the positive electrode of the highest cell having the highest potential and the lowest detection signal connected to the negative electrode of the lowest cell having the lowest potential. This is a voltage between the potential 44 (ground potential) of the line 120. The non-inverting input terminal of the operational amplifier 111 is connected to the other end of the detection line whose one end is connected to the positive electrode of the cell via the resistor 112, and the inverting input terminal of the operational amplifier 111 is connected to the relevant terminal via the resistor 113. It is connected to the other end of the detection line having one end connected to the negative electrode of the cell. A node between the resistor 112 and the non-inverting input terminal of the operational amplifier 111 is connected to the potential 44 via the resistor 114, and a node between the resistor 113 and the inverting input terminal of the operational amplifier 111 is connected to the resistor. 115 is connected to the output terminal of the differential amplifier circuit 70 (the output terminal of the operational amplifier 111).

ここで、直列に接続されたセルの個数をＡ，各セルのセル電圧をＶ１とする。また、抵抗体１１２，１１３の各抵抗値をＲ１，抵抗体１１４，１１５の各抵抗値をＲ２とすると、各差動増幅回路のゲインＧは、周知のとおり、（Ｒ２／Ｒ１）と表すことができる。 Here, the number of cells connected in series is A, and the cell voltage of each cell is V1. Further, when each resistance value of the resistors 112 and 113 is R1, and each resistance value of the resistors 114 and 115 is R2, the gain G of each differential amplifier circuit is expressed as (R2 / R1) as is well known. Can do.

電位の最も低い最下位セルからｎ番目のセルの正極と（ｎ＋１）番目のセルの負極との間の接続点について考えると、当該接続点に一端が接続されたセル間検出線には、当該接続点から電流Ｉ０が流れ出る。電流Ｉ０は、電流Ｉ１と電流Ｉ２とに分流する。 Considering the connection point between the positive electrode of the nth cell and the negative electrode of the (n + 1) th cell from the lowest cell having the lowest potential, the inter-cell detection line having one end connected to the connection point includes Current I0 flows out from the connection point. The current I0 is divided into a current I1 and a current I2.

ｎ番目のセルのセル電圧を差動増幅する差動増幅回路７０に流入する電流Ｉ１は、当該差動増幅回路７０の抵抗体１１２，１１４を経由して、電位４４に流れる。したがって、電流Ｉ１は、オームの法則により、
Ｉ１＝（ｎ×Ｖ１）／（Ｒ１＋Ｒ２）
と表すことができる。 A current I1 flowing into the differential amplifier circuit 70 that differentially amplifies the cell voltage of the nth cell flows to the potential 44 via the resistors 112 and 114 of the differential amplifier circuit 70. Therefore, the current I1 is given by Ohm's law:
I1 = (n × V1) / (R1 + R2)
It can be expressed as.

一方、（ｎ＋１）番目のセルのセル電圧を差動増幅する差動増幅回路７０に流入する電流Ｉ２は、当該差動増幅回路７０の抵抗体１１３，１１５を経由して、当該差動増幅回路７０のオペアンプ１１１の出力端子に流れ込み、電位４４に流れる。差動増幅回路７０の出力電圧（オペアンプ１１１の出力電圧）は、（Ｇ×Ｖ１）であるので、電流Ｉ２は、オームの法則により、
Ｉ２＝（ｎ×Ｖ１−Ｇ×Ｖ１）／（Ｒ１＋Ｒ２）
と表すことができる。 On the other hand, the current I2 flowing into the differential amplifier circuit 70 that differentially amplifies the cell voltage of the (n + 1) th cell passes through the resistors 113 and 115 of the differential amplifier circuit 70, and the differential amplifier circuit 70 70 flows into the output terminal of the operational amplifier 111 and flows to the potential 44. Since the output voltage of the differential amplifier circuit 70 (the output voltage of the operational amplifier 111) is (G × V1), the current I2 is calculated according to Ohm's law.
I2 = (n × V1−G × V1) / (R1 + R2)
It can be expressed as.

電流Ｉ１と電流Ｉ２との和（電流Ｉ３）は、
Ｉ３＝Ｉ１＋Ｉ２＝（２ｎ−Ｇ）×Ｖ１／（Ｒ１＋Ｒ２）
と表すことができる。 The sum of the current I1 and the current I2 (current I3) is
I3 = I1 + I2 = (2n−G) × V1 / (R1 + R2)
It can be expressed as.

ｎ番目のセルの正極と（ｎ＋１）番目のセルの負極との間の接続点に一端が接続されたセル間検出線を最上位検出線１３０にプルアップする抵抗素子Ｒの抵抗値をＲｐｎとすると、抵抗素子Ｒに流れる電流Ｉ４は、
Ｉ４＝（（Ａ−ｎ）×Ｖ１）／Ｒｐｎ
と表すことができる。 The resistance value of the resistance element R that pulls up the inter-cell detection line whose one end is connected to the connection point between the positive electrode of the nth cell and the negative electrode of the (n + 1) th cell to the highest detection line 130 is represented by Rpn. Then, the current I4 flowing through the resistance element R is
I4 = ((A−n) × V1) / Rpn
It can be expressed as.

電流Ｉ４と電流Ｉ３（＝Ｉ１＋Ｉ２）とが一致すれば、電流Ｉ０を零にすることができるので、
（（Ａ−ｎ）×Ｖ１）／Ｒｐｎ＝（２ｎ−Ｇ）×Ｖ１／（Ｒ１＋Ｒ２）
という関係式が得られる。この関係式をＲｐｎについて変形すると、
Ｒｐｎ＝（Ａ−ｎ）×（Ｒ１＋Ｒ２）／（２ｎ−Ｇ）
と表すことができる。 If the current I4 and the current I3 (= I1 + I2) match, the current I0 can be made zero.
((A−n) × V1) / Rpn = (2n−G) × V1 / (R1 + R2)
Is obtained. When this relational expression is transformed with respect to Rpn,
Rpn = (A−n) × (R1 + R2) / (2n−G)
It can be expressed as.

したがって、例えば、Ａ＝４，Ｒ１＝Ｒ２（Ｇ＝１）とすると、
Ｒｐｎ＝２（４−ｎ）×Ｒ１／（２ｎ−１）
という関係が導出されるので、
ｎ＝１の場合、Ｒｐ１＝６×Ｒ１
ｎ＝２の場合、Ｒｐ２＝（４／３）×Ｒ１
ｎ＝３の場合、Ｒｐ３＝（２／５）×Ｒ１
という関係が成立する。よって、Ａ＝４，Ｒ１＝Ｒ２（Ｇ＝１）の場合、図３に記載の抵抗体及びプルアップ抵抗素子の各抵抗値を、
Ｒ１：Ｒ２：Ｒｐ１：Ｒｐ２：Ｒｐ３
＝Ｒ１：Ｒ１：６×Ｒ１：（４／３）×Ｒ１：（２／５）×Ｒ１
＝１５：１５：９０：２０：６
という比率に設定されることにより、隣り合うセル間の接続点から流れ出る電流をいずれの接続点についても零にすることができる。よって、各セルの総放電量は均等に近づくので、セル電圧が各セル間でばらつき難くなる。 Therefore, for example, if A = 4, R1 = R2 (G = 1),
Rpn = 2 (4-n) × R1 / (2n−1)
Is derived, so
When n = 1, Rp1 = 6 × R1
In the case of n = 2, Rp2 = (4/3) × R1
In the case of n = 3, Rp3 = (2/5) × R1
The relationship is established. Therefore, when A = 4, R1 = R2 (G = 1), the resistance values of the resistor and the pull-up resistor element shown in FIG.
R1: R2: Rp1: Rp2: Rp3
= R1: R1: 6 × R1: (4/3) × R1: (2/5) × R1
= 15: 15: 90: 20: 6
By setting the ratio, the current flowing out from the connection point between adjacent cells can be made zero at any connection point. Therefore, since the total discharge amount of each cell approaches equally, the cell voltage is less likely to vary between cells.

図３では、セル電圧Ｖ１が全て等しい場合を例示して説明したが、各セル電圧のバランスが崩れた場合について説明する。例えば、最下位のセルからｎ番目のセルのセル電圧だけが上昇した場合、そのｎ番目のセルの正極に接続されたプルアップ抵抗素子（例えばＡ＝４の場合、Ｒｐ２）に印加される総セル電圧は変化しないので、当該プルアップ抵抗素子に流れる電流Ｉ４も変化しない。これに対し、ｎ番目のセルのセル電圧の上昇により、電流Ｉ１及び電流Ｉ２は増加するため、電流Ｉ０に含まれる、ｎ番目のセルの正極から吐き出される電流は増加する。 In FIG. 3, the case where the cell voltages V1 are all equal is described as an example, but the case where the balance of the cell voltages is lost will be described. For example, when only the cell voltage of the nth cell rises from the lowest cell, the total applied to the pull-up resistor element connected to the positive electrode of the nth cell (for example, Rp2 when A = 4) Since the cell voltage does not change, the current I4 flowing through the pull-up resistor element does not change. On the other hand, since the current I1 and the current I2 increase as the cell voltage of the nth cell increases, the current discharged from the positive electrode of the nth cell included in the current I0 increases.

一方、最下位のセルからｎ番目のセルのセル電圧だけが上昇した場合、ｎ番目のセルの負極（（ｎ−１）番目のセルの正極）に接続されたプルアップ抵抗素子（例えばＡ＝４の場合、Ｒｐ１）に印加される総セル電圧は増加する。よって、当該プルアップ抵抗素子に流れる電流も増加し、（ｎ−１）番目のセルのセル電圧を差動増幅する差動増幅回路に流入する電流は減少するため、ｎ番目のセルの負極に吸い込まれる電流が増加する。すなわち、ｎ番目のセルを放電するように機能する。セル電圧が上昇していない他のセルへの影響もあるが、セル電圧が上昇したセルの放電を促すように動作するため、セル電圧の各セル間の均等化を図ることができる。 On the other hand, when only the cell voltage of the nth cell rises from the lowest cell, a pull-up resistor element connected to the negative electrode of the nth cell (the positive electrode of the (n−1) th cell) (for example, A = In the case of 4, the total cell voltage applied to Rp1) increases. Therefore, the current flowing through the pull-up resistor element also increases, and the current flowing into the differential amplifier circuit that differentially amplifies the cell voltage of the (n−1) th cell decreases, so that the negative electrode of the nth cell The current drawn is increased. That is, it functions to discharge the nth cell. Although there is an influence on other cells in which the cell voltage has not risen, the operation is performed so as to promote the discharge of the cell in which the cell voltage has risen, so that the cell voltage can be equalized between the cells.

図４は、直列に接続された複数のセルのうち対応するセルのセル電圧を差動増幅する差動増幅回路をセル毎に備える電池電圧検出装置４の一具体例を示す図である。図４に示される電池電圧検出装置４は、図３に示される電池電圧検出装置３に対して、遮断回路１４０が追加されている。 FIG. 4 is a diagram illustrating a specific example of the battery voltage detection device 4 including, for each cell, a differential amplifier circuit that differentially amplifies a cell voltage of a corresponding cell among a plurality of cells connected in series. In the battery voltage detection device 4 shown in FIG. 4, a blocking circuit 140 is added to the battery voltage detection device 3 shown in FIG.

電池電圧検出装置４は、セル間検出線を最上位検出線にプルアップする抵抗素子と、差動増幅回路とに流れる電流を遮断する遮断回路１４０と、遮断回路１４０の遮断動作を制御する制御回路１５０とを備える。遮断回路１４０は、例えば、最下位検出線に直列に挿入された最下位スイッチ１４１と、最上位検出線に直列に挿入された最上位スイッチ１４５と、セル間検出線に直列に挿入されたスイッチ１４２〜１４４とを有する。制御回路１５０は、例えば、各セルのセル電圧の検出が不要な場合、スイッチ１４１〜１４５の一部又は全部をオフすることにより、各セルの無駄な放電を防止できる。スイッチ１４２〜１４５は、プルアップ抵抗素子に無駄な電流が流れないようにするため、プルアップ抵抗素子と検出線との接続点に対してセル側に挿入されている。 The battery voltage detection device 4 includes a resistance element that pulls up the inter-cell detection line to the highest detection line, a cutoff circuit 140 that cuts off a current flowing through the differential amplifier circuit, and a control that controls a cutoff operation of the cutoff circuit 140. Circuit 150. The blocking circuit 140 includes, for example, the lowest switch 141 inserted in series with the lowest detection line, the highest switch 145 inserted in series with the highest detection line, and the switch inserted in series with the inter-cell detection line. 142-144. For example, when the detection of the cell voltage of each cell is unnecessary, the control circuit 150 can prevent wasteful discharge of each cell by turning off some or all of the switches 141 to 145. The switches 142 to 145 are inserted on the cell side with respect to the connection point between the pull-up resistor element and the detection line in order to prevent a wasteful current from flowing through the pull-up resistor element.

以上、電池電圧検出装置を実施形態により説明したが、本発明は上記実施形態に限定されるものではない。他の実施形態の一部又は全部との組み合わせや置換などの種々の変形及び改良が、本発明の範囲内で可能である。 The battery voltage detection device has been described above by way of the embodiment, but the present invention is not limited to the above embodiment. Various modifications and improvements such as combinations and substitutions with some or all of the other embodiments are possible within the scope of the present invention.

例えば、直列に接続された複数のセルを複数のグループに分け、複数のグループのそれぞれについて本実施形態の電池電圧検出装置が適用されてもよい。 For example, a plurality of cells connected in series may be divided into a plurality of groups, and the battery voltage detection device of this embodiment may be applied to each of the plurality of groups.

６０組電池
６１〜６４セル
７１〜７４差動増幅回路
８０最下位検出線
８１〜８３セル間検出線
８４最上位検出線
９１〜９３接続点
１０１〜１０３抵抗素子
１４０遮断回路 60 assembled batteries 61-64 cells 71-74 differential amplifier circuit 80 lowest detection lines 81-83 inter-cell detection lines 84 highest detection lines 91-93 connection points 101-103 resistance element 140 cutoff circuit

Claims

With a plurality of cells connected in series,
A differential that operates based on the potential of the lowest detection line connected to the negative electrode of the lowest cell having the lowest potential among the plurality of cells, and differentially amplifies the cell voltage of the corresponding cell among the plurality of cells. Amplifying circuit is provided for each cell,
A connection point between adjacent cells among the plurality of cells differentially amplifies a cell voltage of a cell having a lower potential of the adjacent cell via an inter-cell detection line connected to the connection point. A battery voltage detection device connected to a differential amplifier circuit and a differential amplifier circuit that differentially amplifies the cell voltage of the higher potential cell of the adjacent cell,
A battery voltage detection device, comprising: a resistance element that pulls up the inter-cell detection line to an uppermost detection line connected to a positive electrode of an uppermost cell having the highest potential among the plurality of cells.

The battery voltage detection device according to claim 1, wherein an element that pulls up a detection line between cells having a low potential among the resistance elements has a higher resistance value.

The battery voltage detection apparatus of Claim 1 or 2 provided with the interruption | blocking circuit which interrupts | blocks the electric current which flows into the said resistance element.