JP2007232603A - Voltage detecting device for battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a voltage of a unit cell as either of a single secondary battery in a battery pack constituted as a series connecting body of a plurality of secondary batteries, and a secondary battery constituted by some adjoining batteries with a simpler structure. <P>SOLUTION: The voltages of both ends of the secondary battery B1 are converted into a current by a voltage/current conversion circuit C11 and output to resistance R21. The current is converted into a voltage for a negative electrode potential of a secondary battery B2 as a reference by the resistance R21. The voltage converted by the resistance R21 is converted into a current by a voltage/current conversion circuit C21 and output to resistance R31. The current is converted into a voltage for a negative electrode potential of a secondary battery B3 as a reference by the resistance R31. The voltage converted by the resistance R31 is converted into a current by a voltage/current conversion circuit C31. The current is converted into a voltage for a negative electrode potential of a secondary battery B4 as a reference by the resistance R41. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a set for detecting the voltage of a unit battery which is one of a single secondary battery and a plurality of adjacent secondary batteries in an assembled battery configured as a series connection body of a plurality of secondary batteries. The present invention relates to a battery voltage detection device.

  For example, an assembled battery configured as a series connection body of a plurality of secondary batteries is mounted on a hybrid vehicle or the like. In a hybrid vehicle or the like, the remaining capacity of each secondary battery varies due to temperature variation of each secondary battery, individual differences among assembled batteries, and the like, and the voltage of each secondary battery may vary. For this reason, it is desired to detect the voltage of each secondary battery and make the voltage of each secondary battery uniform. However, since the voltage of the assembled battery becomes high, some secondary batteries have extremely high potentials, making it difficult to detect the voltage of the secondary battery.

  Therefore, conventionally, as seen in Patent Document 1 below, voltage-current conversion means for converting the voltage across each of the electric double layer capacitors connected in series into current, and the output current of the same voltage-current conversion means are the above set. There has also been proposed a voltage detection device including means for converting the negative electrode potential of the battery into a voltage based on the reference. According to this device, it is possible to easily detect the voltage of each secondary battery of the assembled battery by converting the voltage of the capacitor on the high potential side into the voltage of the low potential.

However, in the above apparatus, the capacitor potential and the negative electrode potential of the assembled battery are applied to the output stage of the voltage-current conversion means for converting the voltage of the capacitor on the high potential side into a current. For this reason, it is required that the voltage-current conversion means be configured using a high-breakdown-voltage element that can withstand these potential differences.
JP 09-318679 A

  The present invention has been made in order to solve the above-mentioned problems, and the object thereof is from a single secondary battery and several adjacent ones in an assembled battery configured as a series connection body of a plurality of secondary batteries. An object of the present invention is to provide a voltage detection device for an assembled battery that can detect the voltage of a unit battery, which is one of the secondary batteries, with a simpler configuration.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  The invention according to claim 1 is a voltage-current conversion means for converting a voltage based on one electrode potential of the unit battery into a current, and an output current of the voltage-current conversion means is used as one electrode of another unit battery. A current-voltage conversion means for converting the potential into a voltage based on the potential, and voltages at both ends of two or more unit cells of the plurality of unit cells, the voltage-current conversion means and the current-voltage conversion means And an aggregating portion that is converted into a voltage based on the electrode potential of a specific unit cell by repeating current conversion and voltage conversion according to some methods.

  In the above configuration, each of the voltages at both ends of the two or more unit cells has the electrode potential of any specific unit cell by repeating the current conversion and the voltage conversion by some of the voltage-current conversion unit and the current-voltage conversion unit. It is converted to a reference voltage. For this reason, compared with the case where the voltage of the said both ends is directly converted into the electrode potential of a specific unit battery, the differential pressure | voltage of the voltage added to the output stage of a voltage current conversion means can be reduced. For this reason, compared with the case of direct conversion, the withstand voltage required for the elements constituting the voltage-current conversion means can be reduced, and as a result, the voltage of the unit battery can be detected with a simpler configuration. .

  According to a second aspect of the present invention, in the first aspect of the invention, for each of the two or more unit cells, the voltage of the unit cell is converted to a voltage based on the electrode potential of the specific unit cell. The voltage-current conversion means and the current-voltage conversion means are provided separately for each.

  In the above-described configuration, the voltages at both ends of each of the two or more unit cells can always be converted into a voltage based on the electrode potential of the specific unit cell. For this reason, it is possible to detect the voltages at both ends only by providing means for switching the signal line for taking in the converted signal.

  According to a third aspect of the present invention, in the first aspect of the present invention, as the voltage to be converted by the voltage-current conversion unit, one of the output voltage of the current-voltage conversion unit and the voltage at both ends of the unit cell is selected. It is further characterized by further comprising selection means for doing so.

  In the above configuration, the voltage-current conversion means can be shared between the two or more unit cells. That is, when the voltage of the unit battery to be detected is converted into a current and then converted into a voltage based on one electrode potential of the predetermined unit battery, the predetermined battery is converted into the current again. The conversion target of the voltage-current conversion means that can convert the voltage of the unit battery into a current can be the converted voltage. For this reason, the number of voltage-current conversion means can be reduced.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the voltage of all unit cells constituting the assembled battery is based on the electrode potential of the specific unit cell. It is characterized by being comprised as a single aggregation part which takes out the thing converted into the voltage to make.

  In the above configuration, by using a single converging part, the low voltage driving part that takes in the detected value of the voltage of the unit battery is insulated from the assembled battery side by using a high withstand voltage element only in this single converging part. can do.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the current-voltage conversion means uses the output current of the voltage-current conversion means as a reference based on one electrode potential of an adjacent unit cell. It is the thing converted into the voltage which carries out.

  With the above configuration, the potential difference applied to the output stage of the voltage / current converter can be reduced as much as possible.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, characterized in that the specific unit cell is a unit cell inside the both ends of the series connection body.

  In the above configuration, the number of voltage-current conversion means and current-voltage conversion means used when converting the electrode potential of a specific unit battery into a reference voltage can be reduced, so that errors due to conversion can be reduced. it can.

  A seventh aspect of the invention is characterized in that, in the sixth aspect of the invention, the specific unit cell is a unit cell in a central portion of the series connection body.

  In the above configuration, since the maximum value of the potential difference from a specific unit cell to another unit cell can be minimized, the error associated with the conversion can be further reduced. In particular, when the above configuration has the configurations described in claims 4 and 5, it is suitable for reducing errors associated with the conversion.

(First embodiment)
Hereinafter, a first embodiment in which an assembled battery voltage detection device according to the present invention is applied to an assembled battery voltage detection device mounted on a hybrid vehicle will be described with reference to the drawings.

  In FIG. 1, the whole structure of an assembled battery and a voltage detection apparatus is shown.

  As shown in the drawing, the assembled battery 10 is configured as a series connection body of a plurality of lithium secondary batteries (secondary batteries B <b> 1 to B <b> 7, which are schematically illustrated here in terms of the space of 7). The assembled battery 10 stores electric power generated by the in-vehicle generator, and supplies the stored electric power to a low-voltage (for example, “12V”) in-vehicle battery via a DC-DC converter.

  In this embodiment, in order to detect the voltages of the secondary batteries B1 to B7, in the present embodiment, a voltage / current conversion circuit Cxy (x, y = 1 to 3, 5 to 7) and a resistor Rij (i = i) as current-voltage conversion means. 2-6, j = 1-3, 5-7). As a result, the voltages at both ends of each of the secondary batteries B1 to B3 are converted into a voltage based on the negative potential of the secondary battery B4 by repeating current conversion and voltage conversion, and the secondary batteries B5 to B7. The voltage at each end is converted into a voltage based on the positive electrode potential of the secondary battery B4 by repeating current conversion and voltage conversion.

  Specifically, the voltage-current conversion circuit Cxx is connected in parallel with the secondary batteries B1 to B3 and B4 to B7, respectively, and converts the voltage at both ends into a current. Further, the voltage-current conversion circuit Cxy (x> y or x <y) converts the voltage across the resistor Rij into a current. For example, the voltage across the secondary battery B1 is converted into a current by the voltage-current conversion circuit C11 and output to the resistor R21. This current is converted into a voltage based on the negative electrode potential of the secondary battery B2 by the resistor R21. The voltage converted by the resistor R21 is converted to a current by the voltage / current conversion circuit C21 and output to the resistor R31. This current is converted into a voltage based on the negative electrode potential of the secondary battery B3 by the resistor R31. The voltage converted by the resistor R31 is converted to a current by the voltage / current converter circuit C31 and output to the resistor R41. This current is converted into a voltage based on the negative electrode potential of the secondary battery B4 by the resistor R41.

  Here, the configuration of the voltage / current conversion circuit Cxy will be described using the voltage / current conversion circuit C11 as an example.

  As shown in FIG. 2, the voltage-current conversion circuit C11 includes a detection unit 21 that outputs a signal corresponding to a voltage between two input terminals, and a current mirror circuit 22 that amplifies and outputs the output signal of the detection unit 21. And. Here, in the current mirror circuit 22, the emitter terminals of the transistors 23a and 23b whose bases are connected to each other are connected to the positive electrode side of the secondary battery B1 via the resistors 22a and 22b. The base terminals of the transistors 23 a and 23 b are connected to the collector of the input-side transistor 23 a, and the collector is connected to the output terminal of the detection unit 21 via the resistor 24. The output from the collector of the transistor 23b on the output side becomes the output current of the voltage / current conversion circuit C11.

  The voltage detection circuit 30 shown in FIG. 1 converts the voltages at both ends of the secondary batteries B1 to B3 and B5 to B7 through the signal lines L1 to L3 and L5 to L7 to resistors R41, R42, R43, and R45. , R46, and R47 as a voltage drop amount. Further, the voltage detection circuit 30 takes in the positive electrode potential and the negative electrode potential of the secondary battery B4 via the signal lines L4 and L8, respectively.

  FIG. 3 shows the configuration of the voltage detection circuit 30.

  Here, the multiplexer 31 uses the voltage across the secondary batteries B1 to B4 as the voltage between any of the signal lines L1 to L4 and the signal line L8, and the voltage across the secondary batteries B5 to B8. The voltage is output as a voltage between any one of the signal lines L5 to L7 and the signal line L4. Which of the secondary batteries B <b> 1 to B <b> 7 is selected is set according to a selection signal input via the photocoupler 32. The output of the multiplexer 31 is converted into digital data by the A / D converter 33 and output to the outside through the photocoupler 34 in synchronization with the command signal. Thus, for example, the voltages at both ends of each of the secondary batteries B1 to B7 are acquired as digital data by a microcomputer or the like.

  The photocouplers 32 and 34 insulate the means (microcomputer etc.) side for obtaining the detected value of the voltage across the secondary batteries B1 to B7 of the assembled battery 10 from the assembled battery 10 side which is the high voltage side. It is a means to take. That is, when detecting the voltages at both ends of each of the secondary batteries B1 to B7 of the assembled battery 10, the means (microcomputer or the like) for obtaining the detected value is driven at a much lower voltage than the voltages at both ends of the assembled battery 10. Therefore, it is necessary to configure an interface between the high-voltage assembled battery 10 side and the low-voltage means side using a high-breakdown-voltage element. However, in the present embodiment, the number of high breakdown voltage elements necessary for voltage detection is obtained by converting the voltage across the secondary batteries B1 to B7 into a voltage based on the electrode potential of the secondary battery B4. Can be reduced.

  Furthermore, in the present embodiment, conversion errors due to the voltage-current conversion circuit Cxy and the resistor Rij can be suppressed by converting the electrode potential of the secondary battery B4 at the center of the assembled battery 10 into a reference voltage. This is because the central portion is provided with an aggregating unit (voltage detection circuit 30), whereby the maximum value of the potential difference between the aggregating unit and each of the secondary batteries B1 to B7 can be minimized. This is because the number of conversion circuits Cxy and resistors Rij can be minimized.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) By repeating current conversion and voltage conversion using the voltage / current conversion circuit Cxy and the resistor Rij, the voltages at both ends of the secondary batteries B1, B2, B6, and B7 are used as a reference with respect to the electrode potential of the secondary battery B4. The voltage was converted to As a result, the voltages of the secondary batteries B1 to B7 can be taken out by a common collecting unit (voltage detection circuit 30), so the means side for detecting the voltages of the secondary batteries B1 to B7 and the assembled battery 10 side. It is possible to reduce the number of high breakdown voltage elements used for the interface. In addition, by repeating current conversion and voltage conversion without directly converting the voltages at both ends of the secondary batteries B1, B2, B6, and B7 into the electrode potential of the secondary battery B4, the output stage of the voltage-current conversion circuit Cxy is obtained. The applied potential difference can also be reduced.

  (2) The voltage across each of the secondary batteries B1 to B3 and B5 to B7 is obtained by providing each of the secondary batteries B1 to B3 and B5 to B7 with a separate voltage-current conversion circuit Cxy and a resistor Rij. The voltage can be constantly converted to a voltage based on the electrode potential of the secondary battery B4. For this reason, it is possible to detect the voltages at the both ends only by including the multiplexer 31 that selects any one of the signal lines L1 to L3 and L5 to L7 that take in the converted signal.

  (3) The voltages at both ends of all the secondary batteries B1 to B7 are integrated into a voltage based on the electrode potential of the specific secondary battery B4. Thereby, the low voltage drive part which takes in the detected value of the voltage of secondary battery B1-B7, and the assembled battery 10 side by using a high voltage | pressure-resistant element only for this single aggregation part (voltage detection circuit 30). Can be insulated.

  (4) The potential difference applied to the output stage of the voltage / current conversion circuit Cxy by converting the output current of the voltage / current conversion circuit Cxy into a voltage based on the electrode potential of one of the adjacent unit batteries. Can be reduced as much as possible.

  (5) By appropriately converting the voltages at both ends of the secondary batteries B1 to B7 into a voltage based on the electrode potential of the secondary battery B4 at the center of the assembled battery 10, it is possible to suitably reduce errors associated with the conversion. Can do.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 4 shows the overall configuration of the assembled battery and the voltage detection device according to the present embodiment. In FIG. 4, components having the same functions as those shown in FIG. 1 are given the same reference numerals for convenience.

  As shown in the figure, in the present embodiment, a voltage-current conversion circuit Cx (x = 1 to 3, 5 to 5) that converts a voltage based on one electrode potential of the secondary batteries B1 to B3 and B5 to B7 into a current. 7) is provided with only one each, and the voltage-current conversion circuits C2, C3, C4, C5, C6 are converted to the voltages across the corresponding secondary batteries B2, B3, B5, B6, or the resistance R2 , R3, R5, and R6.

  Here, the switching elements S22 and S33 switch between conduction and interruption between the voltage / current conversion circuits C2 and C3 side and the positive side of each of the secondary batteries B2 and B3, and the switching elements S55 and S66 include the voltage / current conversion circuit C6, Switching between conduction and interruption between the C5 side and the negative side of each of the secondary batteries B6 and B5 is switched. Further, the switching elements S12, S23, and S34 respectively switch conduction and interruption between the voltage / current conversion circuits C1 to C3 side and the resistors R2 to R4a side, and the switching elements S76, S65, and S54 respectively switch to the voltage / current conversion circuits C7 to C7. Switching between conduction and interruption between the C5 side and the resistors R6 to R4b side is switched.

  Furthermore, in this embodiment, the switching element 44a for switching conduction and interruption between the positive electrode potential side of the secondary battery B4 and the voltage detection circuit 30 side, and conduction between the negative electrode potential side of the secondary battery B4 and the voltage detection circuit 30 side. And a switching element 44b for switching off.

  By appropriately switching the switching elements Sij (i = 1 to 3, 5 to 7, j = 2 to 6), S44a and S44b, the two signal lines L10 and L11 are used to connect both ends of the secondary batteries B1 to B7. The voltage can be detected. FIG. 5 shows switching elements Sij, S44a, and S44b that are turned on when detecting voltages across the secondary batteries B1 to B7.

  By appropriately operating the switching element Sij in the above mode, the voltage detection circuit 30 can detect the voltages at both ends of the secondary batteries B1 to B7 via the signal lines L10 and L11 shown in FIG. it can.

  FIG. 6 shows the configuration of the voltage detection circuit 30. As illustrated, the voltage between the signal line L10 and the signal line L11 is applied to the flying capacitor 35 via the switching elements SW1 and SW2. The voltage across the flying capacitor 35 is converted into digital data by the A / D converter 36 via the switching elements SW3 and SW4 as the voltage across the secondary batteries B1 to B7, and is output to the outside. .

  In the voltage detection apparatus shown in FIG. 4, the number of voltage-current conversion circuits and resistors can be reduced as compared with that shown in FIG. 1. For this reason, the number of processes (for example, trimming for adjusting the resistance value) related to the voltage-current conversion circuit and the resistance adjustment can be reduced. Further, according to the configuration shown in FIG. 4, among the detection errors of the voltages at both ends of the secondary batteries B1 to B7, the detection error of the difference between the voltages at both ends of the adjacent secondary batteries B1 to B7 is at most one voltage. This is due to the detection circuit and one resistor. For this reason, compared with the structure shown in previous FIG. 1, the detection error of the differential pressure | voltage of the both-ends voltage of adjacent secondary battery B1-B7 can also be reduced.

  According to this embodiment described above, the following effects can be obtained in addition to the effects (1) and (3) to (5) of the first embodiment.

  (6) Voltages to be converted by the voltage / current conversion circuits C2, C3, C5, and C6 include voltage drop amounts of the resistors R2, R3, R5, and R6 and voltages at both ends of the secondary batteries B2, B3, B5, and B6. A switching element Sij for selecting either one is provided. Thereby, the number of voltage-current conversion circuits and resistors can be reduced as compared with the configuration shown in FIG.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the second embodiment.

  FIG. 7 shows the overall configuration of the assembled battery and the voltage detection device according to the present embodiment. In FIG. 7, components having the same functions as those shown in FIG. 4 are given the same reference numerals for the sake of convenience.

  In the present embodiment, a plurality of voltage detection circuits 30 that are aggregation units for extracting voltages at both ends of the secondary batteries B1 to Bn are provided. Then, the voltage is extracted by a different voltage detection circuit 30 for each group obtained by equally dividing the secondary batteries B <b> 1 to Bn of the assembled battery 10. Here, the number of secondary batteries B1 to Bn in each group is schematically set to seven in FIG.

  For example, when the assembled battery 10 includes 14 secondary batteries B1 to B14, the voltage detection circuit 30 includes two voltage detection circuits 30 and the voltages at both ends of the secondary batteries B1 to B7. And the voltages at both ends of the secondary batteries B8 to B14 are detected by the common voltage detection circuit 30. At this time, the voltage detection circuit 30 detects the voltage with reference to the electrode potential of the secondary battery B4 and the electrode potential of the secondary battery B11. Moreover, when the assembled battery 10 is provided with 21 secondary batteries B1-B21, it is provided with the three voltage detection circuits 30, and seven adjacent (secondary batteries B1-B7, B8-B14, B15-B21). The voltage is detected by the common voltage detection circuit 30 every time. At this time, the voltage detection circuit 30 detects the voltage with reference to the electrode potential of the secondary battery B4, the electrode potential of the secondary battery B11, and the electrode potential of the secondary battery B18.

  According to this embodiment described above, in addition to the effects (1) and (3) of the previous first embodiment and the effect (6) of the previous second embodiment, The effect will be obtained.

  (7) The secondary batteries B1 to Bn of the assembled battery 10 are equally divided, and a common voltage detection circuit 30 is provided for each of the divided groups. Thereby, at the time of voltage detection, conversion errors due to the voltage-current conversion circuit Cx, the resistor Ri, and the like can be reduced.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

  FIG. 8 shows the overall configuration of the assembled battery and the voltage detection device according to the present embodiment. In FIG. 8, components having the same functions as those shown in FIG.

  In the present embodiment, n (≧ 2) secondary batteries Bi1 to Bin (i = 1 to 7) adjacent to each other are taken as one block, and the voltages at both ends of these blocks are detected. Here, when detecting the voltages at both ends of the secondary batteries B11 to B1n, B21 to B2n, B61 to B6n, B71 to B7n, the electrodes of the secondary batteries B41 to B4n are obtained by repeating current conversion and voltage conversion. The potential is converted to a reference voltage. As a result, the withstand voltage required for the output stage of the voltage / current conversion circuit Cxy is reduced as compared with the case where the voltages at both ends of each block are directly converted into voltages based on the electrode potentials of the secondary batteries B41 to B4n. be able to.

  According to the present embodiment described above, the same effects as those of the first embodiment can be obtained.

(Other embodiments)
The above embodiments may be implemented with the following modifications.

  In the first and second embodiments, the voltages at both ends of each of the secondary batteries B1 to B7 of the assembled battery 10 are based on the electrode potential of the secondary battery B4 at the center of the assembled battery 10. Although it converted into voltage, it is not restricted to this. For example, as shown in FIG. 8 as a modification of the second embodiment, the voltage at both ends of each of the secondary batteries B1 to B7 of the assembled battery 10 is converted to a voltage based on the negative electrode potential of the assembled battery 10. It may be.

  In the first to third embodiments, the output current of the voltage / current conversion circuit is converted into a voltage based on the electrode potential of the adjacent secondary battery, but the present invention is not limited to this. For example, in FIG. 1, the output current of the current / voltage conversion circuit C11 may be converted into a voltage based on the negative potential of the secondary battery B3 by the resistor R31. Even in this case, the potential difference applied to the output stage of the voltage-current conversion circuit C11 can be reduced as compared with the case where the voltage of the secondary battery B1 is directly converted to a voltage based on the negative electrode potential of the secondary battery B4. it can.

  The voltage detection circuit 30 is not limited to those illustrated in FIGS. 3 and 6 above. For example, instead of using the A / D converter 33 driven by the potential of the secondary battery B4 in FIG. 3, the output of the multiplexer 31 is made to fly via the switching elements SW1 and SW2 illustrated in FIG. It may be configured to apply to the capacitor 35. In FIG. 6, even if the A / D converter 36 is not included in the voltage detection circuit 30, if the external microcomputer incorporates the A / D converter, both ends of the flying capacitor 35 are thereby connected. May be converted into digital data.

  In each of the above embodiments, the voltage detection circuit 30 is configured using an insulating element such as a photocoupler or a photoMOS relay. However, the insulating element is not limited to such an optical insulating element, and may be a magnetic insulating element such as a so-called pulse transformer that transforms the pulse of the primary coil of the transformer and outputs the pulse to the secondary coil. Further, if a means for making the ground potential on the input side of the voltage detection circuit 30 substantially the same as the ground potential on the output side of the voltage detection circuit 30 is provided, the voltage detection circuit 30 is made of the above-described optical insulating element or magnetic insulating element. It does not have to be configured.

  In each of the above embodiments, the voltage detection device is mounted on the hybrid vehicle. However, the present invention is not limited to this and may be, for example, an electric vehicle.

The circuit diagram which shows the structure of the detection apparatus of the voltage of the both ends of the assembled battery and its each secondary battery in 1st Embodiment. The figure which illustrates the structure of the voltage-current conversion circuit in the embodiment. The figure which shows the circuit structure of the voltage detection circuit in the embodiment. The circuit diagram which shows the structure of the detection apparatus of the voltage of the both ends of the assembled battery and its each secondary battery in 2nd Embodiment. The figure which shows the operation mode of the switching element in the embodiment. The figure which shows the circuit structure of the voltage detection circuit of the embodiment. The circuit diagram which shows the structure of the detection apparatus of the voltage of the both ends of the assembled battery and its each secondary battery in 3rd Embodiment. The circuit diagram which shows the structure of the detection apparatus of the voltage of the both ends of the assembled battery and its each secondary battery in 4th Embodiment. The circuit diagram which shows the structure of the detection apparatus of the voltage of the both ends of the assembled battery and its each secondary battery in the modification of 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Assembly battery, 30 ... Voltage detection circuit, B1-B7 ... Secondary battery, C1-C7, C11-C77 ... Voltage-current conversion circuit, R21-R67 ... Resistance (one embodiment of a current-voltage conversion means).

Claims (7)

Voltage detection of an assembled battery that detects a voltage of a unit battery that is one of a single secondary battery and a plurality of adjacent secondary batteries in an assembled battery configured as a series connection body of a plurality of secondary batteries. In the device
Voltage-current conversion means for converting a voltage based on one electrode potential of the unit battery into a current;
Current-voltage conversion means for converting the output current of the voltage-current conversion means into a voltage based on one electrode potential of another unit battery; and
The voltage across each of two or more unit cells of the plurality of unit cells is a specific unit cell by repeating current conversion and voltage conversion by the voltage-current conversion unit and some of the current-voltage conversion units. A voltage detector for an assembled battery, comprising: an aggregating unit that is converted into a voltage with reference to the electrode potential of the battery and extracted.   For each of the two or more unit cells, the voltage-current conversion unit and the current-voltage conversion unit for converting the voltage of the unit cell into a voltage based on the electrode potential of the specific unit cell, 2. The assembled battery voltage detection device according to claim 1, wherein the voltage detection device is provided separately.   2. A selection means for selecting one of an output voltage of the current-voltage conversion means and a voltage at both ends of the unit battery as a voltage to be converted by the voltage-current conversion means. The voltage detection apparatus of the assembled battery as described.   The aggregating unit is configured as a single aggregating unit that takes out the voltages obtained by converting the voltages of all unit cells constituting the assembled battery into voltages based on the electrode potential of the specific unit cell. The assembled battery voltage detection device according to any one of claims 1 to 3.   5. The current-voltage conversion unit converts the output current of the voltage-current conversion unit into a voltage based on one electrode potential of an adjacent unit cell. The voltage detection apparatus of the assembled battery as described.   The assembled battery voltage detection device according to claim 1, wherein the specific unit battery is a unit battery inside the both ends of the series connection body.   7. The assembled battery voltage detection device according to claim 6, wherein the specific unit battery is a unit battery in a central portion of the series connection body.

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