JP2010164590A - Driving method of flying capacitor type battery pack voltage detection circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flying capacitor type voltage detection circuit reducing power consumption, and detecting a disconnection failure. <P>SOLUTION: An odd-numbered read cycle for reading in due order, voltages of each odd-numbered battery module, and outputting it to a differential amplifying circuit, and an even-numbered read cycle for reading out in due order, voltages of each even-numbered battery module, and outputting it to the differential amplifying circuit, are executed alternately. Further, a head battery module in the odd-numbered read cycle and a head battery module in the even-numbered read cycle in each read cycle are shifted in due order. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flying capacitor type voltage detection circuit.

  Electric vehicles and hybrid vehicles use high-voltage and large-capacity secondary batteries that store power used as driving energy, and even in fuel-cell vehicles, the use of high-voltage and large-capacity secondary batteries as a buffer for fuel cell output fluctuation is considered suitable. It is done.

  In the above application, the secondary battery is used in an assembled battery configuration in which a large number of unit cells (hereinafter also simply referred to as cells) are cascaded. For the management measurement of the assembled battery, a predetermined number of one to continuously cascaded batteries are used. Each cell is classified as a module, and the battery voltage is measured for each module.

  Japanese Patent Application Laid-Open No. 11-248755 proposes a voltage detection technique using a flying capacitor. In this flying capacitor type voltage detection circuit, first, a pair of input side sampling switches are turned on, both ends of the module are connected to both ends of the flying capacitor, and the module voltage is sampled and held in the flying capacitor. Next, after the input side sampling switch is turned off, the pair of output side sampling switches are turned on to apply the storage voltage of the flying capacitor between the pair of input terminals of the differential amplifier circuit.

Japanese Patent Laid-Open No. 11-248755

  In the above-described conventional flying capacitor type voltage detection circuit, the sampling switch needs to increase the capacity of the flying capacitor due to the leakage current when it is off, and to reduce the decrease in the storage voltage of the flying capacitor due to this leakage current. .

  However, the increase in the capacity of the flying capacitor increases the power consumption of the flying capacitor type voltage detection circuit as compared with that of other assembled battery voltage detection circuits such as a resistance voltage dividing type, and also causes variations in capacity between modules. There was a problem that it was likely to occur.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a flying capacitor type voltage detection circuit that realizes reduction in power consumption.

  The present invention relates to a flying capacitor circuit having at least one flying capacitor, and N (N ≧ 2) battery modules that are connected in series to form a battery pack, with both ends of the flying capacitor circuit being connected to each battery module. Are sequentially connected to each other, and the voltage of each battery module always charges the flying capacitor circuit in the same direction, a differential amplifier circuit, and a pair of input terminals of the differential amplifier circuit at both ends of the flying capacitor circuit. In a flying capacitor type assembled battery voltage detection circuit comprising a pair of output side sampling switches connected individually to each other, after the storage voltage of the flying capacitor circuit is read to the differential amplifier circuit through the output side sampling switch, and Next voltage of the battery module Is preferably applied to a flying capacitor type battery pack voltage detection circuit having a reset circuit for attenuating the stored voltage by short-circuiting the flying capacitor circuit before loading in the flying capacitor circuit through the multiplexer.

  The flying capacitor circuit is preferably composed of one or two flying capacitors connected in series. The reset circuit is preferably configured by connecting one reset switch and a short-circuit current regulating discharge resistor in series.

  According to that aspect, the multiplexer always charges the flying capacitor circuit in the same direction. For this reason, the amount of charge transferred from the battery module to the flying capacitor circuit in the next reading of the voltage of the battery module can be reduced by the stored voltage remaining in the flying capacitor circuit charged by the previous reading of the voltage of the battery module. The battery module can be prevented from discharging. However, in this same direction readout type multiplexer, even if charge transfer from the predetermined battery module to the flying capacitor circuit is not performed due to disconnection failure or off failure of the multiplexer circuit, the previous battery module to the flying capacitor circuit Since the stored voltage read into the flying capacitor circuit remains in the flying capacitor circuit, the problem of erroneously reading out this residual charge as the current signal voltage is inevitably derived. Equipped with a reset circuit that discharges, after the signal voltage from the flying capacitor circuit to the differential amplifier circuit, the reset circuit is turned on to reset or erase the stored voltage of the flying capacitor of the flying capacitor circuit by discharging. So do Maru If the disconnection failure or off-failure of plexer occurs, the signal voltage can be fractionated from the voltage of the large battery modules therewith.

  According to this aspect, the multiplexer includes N + 1 input-side sampling switches whose one ends are connected to the highest potential end, each connection end, and the lowest potential end of each battery module, and the odd-numbered input-side sampling switches. A second switch for individually connecting the other end of each of the odd-numbered input side sampling switches to the other end of the flying capacitor circuit; an even number; A third switch that individually connects each other end of the th-th input side sampling switch to one end of the flying capacitor circuit, and each other end of the even-numbered input-side sampling switch individually to the other end of the flying capacitor circuit A fourth switch to be connected; Because and a current switching circuit for charging is always in the same direction the queuing capacitor circuit, it is possible to power storage voltage of all battery modules in the same direction flying capacitor of the flying capacitor circuit with a simple circuit configuration.

  According to this aspect, since the disconnection failure is determined based on the voltage of the battery module read out immediately after the short-circuit discharge operation of the reset circuit, it is ensured when a disconnection failure or an off-failure of the multiplexer occurs. Can be detected, and the reliability of the apparatus is improved.

  According to the aspect, the voltage of the battery module is read into the flying capacitor circuit through the multiplexer, the stored voltage of the flying capacitor circuit is output to the differential amplifier circuit through the output side sampling switch, and the output side sampling switch The battery module read out after the short-circuit operation is performed after performing a short-circuit discharge operation of the flying capacitor circuit by the reset circuit after performing a read cycle for sequentially reading the voltage of each battery module by turning off It is characterized by changing in order.

  The operation of reading the voltage of the battery module to the flying capacitor immediately after the reset operation consumes the amount of stored power (storage energy) of the battery module because there is no residual voltage in the same direction in the flying capacitor. Therefore, according to this configuration, the reset operation is performed after the voltage of the battery module is performed many times, so that power consumption of the battery module due to the reset operation can be reduced. Furthermore, in this configuration, the order of the battery modules read immediately after the reset operation is changed in order, so that all the battery modules can be consumed in order by the reset operation, and only a specific battery module is not consumed by the reset operation. .

  According to the aspect, the flying capacitor is partially discharged (for example, discharge amount is 10% or more and less than 50%) by the short-circuit discharge operation of the flying capacitor circuit by the reset circuit.

  According to this configuration, the reset period is set so that the stored voltage having a discharge amount of 10% or more and less than 50% remains in the flying capacitor even after the reset operation. If it does in this way, the electrical storage energy of the battery module lost in reading of the voltage of the battery module immediately after reset operation can be reduced.

  In this case, in normal operation, the voltage variation between the battery modules is less than 50% of the voltage of the battery modules, and therefore the voltage of the battery modules read out to the differential amplifier circuit via the flying capacitor immediately after the reset operation is If it is 50% or less, it is possible to reliably determine that the disconnection failure or off failure of the multiplexer is not a decrease in the voltage of the battery module. In addition, the voltage of the battery module may be abnormally reduced and may be reduced to 50% or less of the voltage of the battery module read immediately before. In this case, it is not possible to distinguish between a disconnection failure or an off failure of the multiplexer, but in any case, it can be determined that there is some abnormality. Further, in this case, if the reset period is increased in the next reset operation for the battery module determined to be abnormal, the amount of decrease in the stored voltage of the flying capacitor immediately after the reset operation can be increased. It can be done reliably.

  According to this aspect, the turn-on period of the reset circuit is adjusted based on each module voltage read last time.

  That is, the voltage of the battery module is read to the flying capacitor every fixed short period, and it is impossible for the battery module voltage to change suddenly in such a short period of time, so it is based on the voltage of the battery module read normally last time. Then, when it is read out immediately before the reset operation, the reset period is shortened so that the residual voltage after the reset operation can be distinguished from the voltage of the battery module immediately after the reset operation and the flying capacitor residual voltage after the reset operation. If it does in this way, the amount of battery module discharge by reset operation can be reduced. Of course, even in this case, if it is determined that the voltage of the battery module read out to the differential amplifier circuit immediately after the reset operation is a disconnection failure or an off-failure, the reset operation period in the next reset operation of this battery module voltage Can be sufficiently extended to perform a determination operation for distinguishing between a disconnection failure, an off failure, and an abnormal battery voltage sudden decrease.

  A flying capacitor type assembled battery voltage detection circuit according to a first aspect of the present invention includes a flying capacitor circuit having at least one flying capacitor and both ends of N (N> 2) battery modules that are connected in series to form an assembled battery. A multiplexer that sequentially connects to both ends of the flying capacitor circuit for each battery module, and alternately charges the flying capacitor circuit with the voltage of each battery module every time the voltage of the battery module is read; and a differential amplifier circuit; A pair of output side sampling switches that individually connect a pair of input terminals of the differential amplifier circuit to both ends of the flying capacitor circuit, and the multiplexer has one end at the highest potential end of each battery module, N + 1 inputs connected to connection end and lowest potential end In a driving method of a flying capacitor type assembled battery voltage detection circuit constituted by a sampling switch, an odd number reading is sequentially read out to the flying capacitor circuit, and a cycle in which the voltage is output to the differential amplifier circuit is performed. After that, the voltage of the even-numbered battery module is sequentially read out to the flying capacitor circuit, and a read cycle is performed in which an even-numbered read cycle is output to the differential amplifier circuit.

  According to this configuration, the multiplexer is configured by N + 1 input-side sampling switches each having one end connected to the highest potential end, each connection end, and the lowest potential end of each battery module. In the case of reading the voltage and in the case of reading the voltage of the even-numbered battery module, the flying capacitor circuit is charged in the reverse direction, so the battery module reverses the flying capacitor circuit that stores the remaining power in one direction. The battery module has a large power loss.

  Therefore, in this configuration, the odd-numbered read cycle for continuously reading the voltages of the odd-numbered battery modules and the even-numbered read cycle for continuously reading the voltages of the even-numbered battery modules are alternately performed. Thereby, even if the multiplexer does not align the charging direction of the flying capacitor circuit in one direction, the power loss of the battery module accompanying the voltage reading of the battery module can be greatly reduced.

  In this configuration, the above-described reset switch for resetting the flying capacitor circuit does not have to be provided. However, in the case of providing, it is preferable to reset only when switching between the odd-numbered read cycle and the even-numbered read cycle. By performing this reset operation, the reverse residual charge of the flying capacitor circuit can be lost in the voltage reading of the first battery module in the odd-numbered read cycle and the voltage reading of the first battery module in the even-numbered read cycle. Therefore, the power loss of the battery module can be reduced.

  According to a preferred aspect, the disconnection failure is determined based on a read voltage of the first battery module in the odd read cycle and a read voltage of the first battery module in the even read cycle. According to this configuration, it is possible to determine whether or not there is a disconnection failure in the readout circuit portion of the multiplexer that reads out the battery module immediately after the cycle is changed. That is, if this disconnection occurs, the stored voltage in the direction opposite to the original direction is read from the flying capacitor circuit, so that the disconnection failure or the off failure can be easily determined.

  According to a preferred aspect, it has a reset circuit that short-circuits the flying capacitor circuit and attenuates the stored voltage immediately before reading the voltage of the battery module at the head of each of the odd read cycle and the even read cycle. It is said.

  According to this configuration, it is possible to prevent a reverse voltage from being applied to the differential amplifier circuit at the time of a disconnection failure or an off failure, and to reduce the power loss of the battery module voltage.

  According to a preferred aspect, the battery module at the head of the odd read cycle in each read cycle and the battery module at the head of the even read cycle in each read cycle are sequentially shifted.

  According to this configuration, since the battery modules read immediately after the cycle are changed in order, it is possible to determine a disconnection failure or an off failure for the voltage reading paths of all the battery modules. Moreover, all the battery modules can be consumed evenly.

  A flying capacitor type assembled battery voltage detection circuit according to a second aspect of the present invention includes a flying capacitor circuit having at least one flying capacitor and both ends of N (N> 2) battery modules connected in series to form an assembled battery. A multiplexer that sequentially connects to both ends of the flying capacitor circuit for each battery module and charges the flying capacitor circuit alternately or always with the same polarity for each voltage reading of the battery module by the voltage of each battery module; In a driving method of a flying capacitor type assembled battery voltage detection circuit comprising: a differential amplifier circuit; and a pair of output side sampling switches that individually connect a pair of input terminals of the differential amplifier circuit to both ends of the flying capacitor circuit; The voltage of each battery module is Each read cycle sequentially read out by the Rigge capacitor circuit and output to the differential amplifier circuit includes M (M> N) voltage reading steps of the battery module performed every predetermined period. A plurality of the voltage reading steps in the reading cycle, the voltage of the predetermined number of the battery modules is read a plurality of times, and the second voltage reading step of the predetermined battery module that is read a plurality of times in the reading cycle The storage direction of the flying capacitor circuit is the same as the storage direction of the flying capacitor in the immediately preceding voltage reading step.

  That is, in this configuration, the flying capacitor type assembled battery voltage detection circuit performs module voltage detection M times with a period T. However, when the assembled battery has less than M battery modules, the circuit is idle. Therefore, in the remaining voltage reading period of the battery module after reading the voltage of each battery module, the voltage of a predetermined battery module of the assembled battery is read again to increase the number of measurements.

  However, in this configuration, the multiplexer is composed of N + 1 input-side sampling switches each having one end connected to the highest potential end, each connection end, and the lowest potential end of each battery module. In the case of reading the voltage and in the case of reading the voltage of the even-numbered battery module, the flying capacitor circuit is charged in the reverse direction, so the battery module reverses the flying capacitor circuit that stores the remaining power in one direction. The battery module has a large power loss.

Therefore, in this configuration, the battery module that is double read out has the same charging direction as the battery module read out immediately before.
Thereby, it is possible to reduce the power loss of the battery module that is double-readed.

  In this configuration, it is preferable that the odd-numbered read cycle for continuously reading the voltage of the odd-numbered battery module and the even-numbered read cycle for continuously reading the voltage of the even-numbered battery module are alternately performed. . Thereby, even if the multiplexer does not align the charging direction of the flying capacitor circuit in one direction, the power loss of the battery module accompanying the voltage reading of the battery module can be greatly reduced.

  According to a preferred aspect, the combination of the battery modules read a plurality of times in the one read cycle is sequentially changed.

  However, in the above method, when the battery module that is double-readed as described above is fixed, the consumption of the battery module is accelerated. Therefore, in this configuration, since the battery modules that are double-read are sequentially changed, the capacity variation of the battery modules due to the double-reading can be reduced.

  According to a third aspect of the present invention, there is provided a flying capacitor type assembled battery voltage detecting circuit including a flying capacitor circuit having at least one flying capacitor and N (N> 2) battery modules that are connected in series to form an assembled battery. A multiplexer that sequentially connects to both ends of the flying capacitor circuit for each battery module, and alternately charges the flying capacitor circuit with the voltage of each battery module every time the voltage of the battery module is read; and a differential amplifier circuit; In the driving method of a flying capacitor type assembled battery voltage detection circuit comprising a pair of output side sampling switches that individually connect a pair of input terminals of the differential amplifier circuit to both ends of the flying capacitor circuit, Voltage to the flying capacitor Each read cycle sequentially read out to the path and output to the differential amplifier circuit includes M (M> N) battery module voltage reading steps performed every predetermined period, and each read cycle The odd-numbered read cycle in which the voltages of all odd-numbered battery modules are sequentially read out to the flying capacitor circuit and output to the differential amplifier circuit; and the voltages of all even-numbered battery modules are output to the flying capacitor. A predetermined battery module that is read in sequence to a circuit and outputs an even number read cycle that is output to the differential amplifier circuit, and then reads a voltage of a predetermined number of the battery modules a plurality of times and is read a plurality of times in the read cycle. The flying capacitor by the second voltage reading step The power storage Road direction, the power storage in the same direction as the direction of the flying capacitor immediately before the voltage reading step, and a plurality of times, characterized in that successively changing the combination of the battery module to be read.

  That is, in this configuration, the flying capacitor type assembled battery voltage detection circuit performs module voltage detection M times with a period T. However, when the assembled battery has less than M battery modules, the circuit is idle. Therefore, in the remaining voltage reading period of the battery module after reading the voltage of each battery module, the voltage of a predetermined battery module of the assembled battery is read again (double reading) to increase the number of measurements.

  However, if double reading is performed, only the power loss of the battery module that has been double read increases.

  Therefore, in this configuration, the battery modules that are double-read selected for each read cycle are sequentially replaced. In this way, all battery modules are double-read once after x read cycles, and the voltage variation of the battery modules can be reduced.

  In this configuration, the odd-numbered read cycle for continuously reading the voltage of the odd-numbered battery module and the even-numbered read cycle for continuously reading the voltage of the even-numbered battery module are alternately performed. Thereby, even if the multiplexer does not align the charging direction of the flying capacitor circuit in one direction, the power loss of the battery module accompanying the voltage reading of the battery module can be greatly reduced.

  When a reset switch for resetting is provided, it is preferable to perform reset only when switching between the odd-numbered read cycle and the even-numbered read cycle. By performing this reset operation, the reverse residual charge of the flying capacitor circuit can be lost in the voltage reading of the first battery module in the odd-numbered read cycle and the voltage reading of the first battery module in the even-numbered read cycle. Therefore, the power loss of the battery module can be reduced.

1 is a circuit diagram illustrating a flying capacitor type voltage detection circuit according to Embodiment 1; FIG. 6 is a circuit diagram illustrating a flying capacitor type voltage detection circuit according to Embodiment 2. FIG. FIG. 6 is a circuit diagram illustrating a modification of the first embodiment. FIG. 6 is a circuit diagram illustrating a flying capacitor type voltage detection circuit according to a third embodiment. FIG. 6 is a circuit diagram illustrating a flying capacitor type voltage detection circuit according to a fourth embodiment.

  Hereinafter, preferred embodiments of the flying capacitor type voltage detection circuit of the present invention will be described in detail with reference to the following examples.

  (Circuit Configuration) An assembled battery voltage detection apparatus to which the present invention is applied will be described with reference to a circuit diagram shown in FIG.

  DESCRIPTION OF SYMBOLS 1 is a battery for driving power storage for hybrid electric vehicles, 2 is a multiplexer, 3 is a flying capacitor circuit composed of one flying capacitor C3, 4 is an output side sampling switch circuit, 5 is a differential amplifier circuit, and 6 is reset The multiplexer 2 reads the signal voltage from the battery 1 to the flying capacitor circuit 3, and the output side sampling switch circuit 4 reads the signal voltage from the flying capacitor circuit 3 to the differential amplifier circuit 5. R20 is a current limiting resistor that limits the discharge current of the flying capacitor circuit 3.

  The battery 1 is formed by connecting eight battery modules VB10 to VB17 in series.

  The multiplexer 2 has N + 1 input-side sampling switches whose one ends are individually connected to the highest potential end and the lowest potential end of the battery 1 and the connection ends of the battery modules VB10 to VB17 via current limiting resistors R10 to R18, respectively. The input side sampling switch circuit 21 including SSR10 to SSR18 and the switching circuit 22 that switches the power transmission direction of the signal voltage read from the input side sampling switch 21 circuit and sends the signal voltage to the flying capacitor circuit 3.

  The switching circuit 22 includes four switches SW00 to SW03 that are analog switches. The switch (first switch) SW00 individually connects the other ends of the odd-numbered switches SSR10, SSR12, SSR14, SSR16, and SSR18 to one end of the flying capacitor C3. The switch (second switch) SW01 individually connects the other ends of the odd-numbered switches SSR10, SSR12, SSR14, SSR16, and SSR18 to the other end of the flying capacitor C3. The switch (third switch) SW02 individually connects the other ends of the even-numbered switches SSR11, SSR13, SSR15, and SSR17 to one end of the flying capacitor C3. A switch (fourth switch) SW03 individually connects the other ends of the even-numbered switches SSR11, SSR13, SSR15, and SSR17 to the other end of the flying capacitor C3. By simultaneously turning on the switches SW00 and SW03, the signal voltages of the odd-numbered battery modules VB10, VB12, VB14, VB16, and VB18 are read out to the flying capacitor C3, and the flying capacitor C3 is charged in one direction. By simultaneously turning on the switches SW01 and SW02, the signal voltages of the even-numbered battery modules VB11, VB13, VB15, and VB17 are read out to the flying capacitor C3, and the flying capacitor C3 is charged in one direction. That is, the switching circuit 22 performs the above operation in synchronization with the input side sampling switches SSR10 to SSR18 of the input side sampling switch circuit 21, and always charges the flying capacitor C3 in the same direction by the signal voltage of each of the battery modules VB10 to VB17. .

  The output side sampling switch circuit 4 includes switches SSR21 and SSR22 as a pair of output side sampling switches. The switch SSR21 connects one end of the flying capacitor C3 to one input end of the differential amplifier circuit 5, and the switch SSR22 is a flying capacitor. The other end of C3 is connected to the other input end of the differential amplifier circuit 5.

  The differential amplifier circuit 5 is composed of a normal operational amplifier voltage amplifier circuit, Vref is a reference power supply, and the potential of the other input terminal (+ input terminal) of the operational amplifier OP is set to the reference potential through a resistor.

  The reset circuit 6 includes a reset switch SSR26 and a short-circuit current limiting resistor element R20 connected in series with each other, and is connected in parallel with the flying capacitor C3.

(Description of Basic Operation) The basic operation of the circuit of FIG. 1 will be described below.
Each pair of switches SSR10 to SSR18 connected to both ends of each of the battery modules VB10 to VB17 is turned on in turn in the first half period of a predetermined voltage module readout period ΔT repeated at a constant period, and at the same time, the switching circuit 22 The switches SW00 to SW03 are synchronously turned on as described above, and the voltages (also referred to as module voltages) of the battery modules VB10 to VB17 are sequentially read out. In the second half of each predetermined period ΔT, the switches SSR10 to SSR18 are turned off, the switches SSR21 and SSR22 of the output side sampling switch circuit 4 are turned on, and the stored voltage of the flying capacitor C3 is read to the differential amplifier circuit 5.

  The reset switch SR26 of the reset circuit 6 is turned on at the final stage of the latter half of the voltage module readout period ΔT, and attenuates or erases the stored voltage remaining in the flying capacitor C3. At this time, by adjusting the ON period of the reset switch SR26, the ratio of the residual voltage of the flying capacitor C3 can be determined. The reset operation includes a signal voltage (not including the storage voltage of the battery module) read out to the differential amplifier circuit 5 after the reset operation in a state where the disconnection failure or off failure of the multiplexer 2 occurs, and the battery module having the lowest possible voltage. In view of reducing the power loss of the battery module, it is preferable to make the residual voltage as large as possible (preferably 50% or more) within a range where the voltage can be distinguished.

  (Disconnection failure or off failure detection operation 1) With the above operation, the voltages of the battery modules VB10 to VB17 can be sequentially transferred to the differential amplifier circuit 5, and the voltage of the next battery module is read after the reset switch SSR26 is turned on. If the multiplexer 2 is broken or off, the signal voltage read from the battery module to the flying capacitor C3 cannot be read, and the signal voltage read from the flying capacitor C3 to the differential amplifier circuit 5 is zero. . Therefore, by determining the voltage level of the battery module immediately after the reset switch SSR26 is turned on, it is possible to easily detect a disconnection failure or an OFF failure in the current path of the multiplexer 2 related to the voltage reading of the battery module. .

  (Disconnection failure or off failure detection operation 2) The voltages of all the battery modules VB10 to VB17 are sequentially read from the VB10 to the differential amplifier circuit 5, and after executing a read cycle for reading the voltage of VB17, the reset switch (SW1 in the drawing) When the SSR 26 is turned on (which is also described), the battery module connected to the flying capacitor C3 immediately after that is discharged to charge the flying capacitor C3. This problem is particularly serious when only certain battery modules are always selected immediately after this reset operation. In addition, it is possible to detect only a disconnection failure or an off failure in the current path connected to the specific battery module.

  Therefore, the battery module selected immediately after the reset operation is changed in order for each read cycle. Thereby, the capacity variation between battery modules can be reduced.

  (Modification) In the above example, all the battery modules are read once in one read cycle period, and the read order of the battery modules in each read cycle is changed, but instead, the battery modules are read in one read cycle period. A number exceeding the number may be read, and some battery modules may be read twice within one read cycle period. In this case, the reading order of the battery modules is the same. In this way, since the battery modules read immediately after the reset operation are shifted by the number of battery modules to be read an extra number of times, all the battery modules can be evenly arranged immediately after the reset operation. The number of battery modules to be read an extra number is preferably 1. However, it may not be 1 as long as all battery modules are arranged immediately after the reset operation as the cycle is repeated.

  Alternatively, only the battery module read for the second time corresponding to the battery module for reading this extra number of times may be read for each read cycle.

  (Reset operation) If the previous read voltage of the battery module voltage read immediately after the reset operation is stored, and the reset period is set so that a voltage smaller than the stored value by a predetermined value remains in the flying capacitor C3, It is possible to reduce power loss of useless battery modules.

  (Modification) By changing the number of reset operations or the ON period according to the voltage of the battery module, it is possible to reduce the voltage variation between the battery modules VB10 to VB17. That is, the ON period of the reset operation performed immediately before reading the battery module having a large previous read voltage value is lengthened, or the average number of reset operations performed immediately before the battery module having a large previous read voltage value Or the like, the decrease in the storage voltage of the battery module having a large previous read voltage value can be promoted, and the voltage variation can be reduced.

  (Modification) In the above embodiment, the reset switch SSR26 is turned on after the output side sampling switches SSR21 and SSR22 of the output side sampling switch circuit 4 are turned off. However, the reset switch SSR26 is turned on. The output side sampling switches SSR21 and SSR22 of the circuit 4 may be implemented in the latter half of the ON period. In this way, the charge remaining in the parasitic capacitance of the signal line connecting the output side sampling switches SSR21, SSR22 and the operational amplifier OP can also be canceled, so that a reduction in reading accuracy due to the residual charge can be reduced.

  Another embodiment of the present invention will be described below with reference to FIG.

  In this embodiment, the consumption of the battery modules VB10 to VB17 due to the flying capacitor C3 is reduced by using a multiplexer in which the switching circuit 22 of the multiplexer 2 shown in FIG. 1 is omitted.

  In this type of conventional circuit, the switches SSR10 to SSR18 of the input side sampling switch circuit 21 are sequentially turned on in the adjacent order. For this reason, since the battery modules VB10 to VB17 always discharge the residual voltage stored in the reverse direction and then store their own voltage in the flying capacitor C3, the battery modules VB10 to VB17 are greatly consumed.

  Therefore, in this embodiment, the voltage reading cycle of each battery module is performed as follows to reduce the consumption of the battery module. First, an odd read cycle for sequentially reading all voltages of the odd-numbered battery modules is performed, and then an even-number read cycle for sequentially reading all voltages of the even-numbered battery modules is performed. In this way, the capacity of the battery module is significantly consumed by the residual voltage in the reverse direction of the flying capacitor C3 only in the first battery module of the odd read cycle and the even read cycle. Therefore, consumption of other battery modules can be reduced.

  (Modification) Also in this embodiment, the reset switch SSR26 (SW1) is turned on immediately after the switches SSR21 and SSR22 are turned on immediately before the voltage reading of the first battery module in the odd read cycle and the even read cycle. It is possible to reduce the consumption of the battery module.

  (Modification) However, also in the above-described second embodiment, when the battery module read first in each of the odd read cycle and the even read cycle is always fixed to a part, the voltage between the battery modules VB10 to VB17 is fixed. Variation increases.

  Therefore, the battery modules that are read first in the odd read cycle and the even read cycle are changed in turn. Thereby, it is possible to substantially equalize the consumption of the battery modules VB10 to VB17 due to the charge transfer to the flying capacitor C3.

  Of course, in this case as well, it is preferable to turn on the reset switch SSR 26 before reading the voltage of the battery module first in each of the odd read cycle and the even read cycle, thereby reducing charge carry-out from the battery module.

  (Modification) In the above embodiment, a disconnection failure or an off failure (for example, a disconnection or a failure in which the switch of the multiplexer 2 is not turned on) is applied to the voltage of the battery module at the beginning of each of the odd read cycle and the even read cycle. The reset operation by the reset switch SSR26 is performed at the end of the odd read cycle and the even read cycle, and can be performed based on the voltage of the battery module read immediately thereafter.

  (Modification) In the second embodiment, each odd read cycle is a cycle for reading the voltage of the odd-numbered battery module once, and the even read cycle is a cycle for reading the voltage of the even-numbered battery module once. However, the number of battery module reads included in one odd read cycle and one even read cycle can be arbitrarily set.

  For example, in an odd read cycle of the read cycles, voltages of a predetermined combination of odd-numbered battery modules are sequentially read, and thereafter, voltages of a predetermined combination of even-numbered battery modules are sequentially read.

  Each odd read cycle may include an odd-numbered battery module that is read only once and an odd-numbered battery module that is read multiple times. Similarly, an even-numbered battery module is an even-numbered battery module that is read only once. And even-numbered battery modules that are read a plurality of times, and in addition, all even-numbered battery modules and even-numbered battery modules that are subjected to additional reading can be included. . However, the average probability that each battery module VB10 to VB17 comes immediately after the odd read cycle or the even read cycle and the voltage read frequency of each battery module are equalized as a whole, thereby equalizing the consumption of each battery module VB10 to VB17. can do.

  Alternatively, each odd read cycle can include a portion of an odd-numbered battery module, and can also include a portion of an even-numbered battery module. The next odd read cycle can include the remainder of the odd-numbered battery modules, and can also include the remainder of the even-numbered battery modules. That is, the voltage reading of the odd-numbered battery modules is completed by a plurality of odd-numbered read cycles, and the voltage reading of the even-numbered battery modules is completed by a plurality of even-numbered read cycles. However, the average probability that the voltage modules VB10 to VB17 come immediately after the odd read cycle or the even read cycle and the voltage read frequency of each battery module are equalized as a whole, thereby reducing the consumption of each battery module VB10 to VB17. Can be equalized.

  In this example, in particular, the total number of battery module reads in one odd read cycle or one even read cycle of the flying capacitor type assembled battery voltage detection circuit and the actual number of battery modules in the battery 1 are the circuit or Even if there is a mismatch due to the battery design change, there is an advantage that the voltage of each battery module can be read out evenly without any trouble and the consumption of each battery module can be equalized.

  (Modification) In the above modification, the voltage of each battery module is read as a whole at an equal frequency, regardless of the mismatch between the number of battery modules of the battery 1 and the number of battery module readings performed in one reading cycle. In addition, the battery module consumption in this reading was averaged, and a complete odd read cycle for reading the voltages of all odd-numbered battery modules, and a complete even-numbered read cycle for reading the voltages of all even-numbered battery modules, Is first executed, and then a partial read cycle in which a predetermined combination of a part of the odd-numbered battery modules or the even-numbered battery modules is additionally read can be performed. Even in this case, the battery modules read immediately after changing the reading of at least the odd-numbered battery modules and the reading of the even-numbered battery modules are changed in order, and the consumption levels of the battery modules VB10 to VB17 are averaged. Is done. In this case, the direction in which the battery module read in the additional partial read cycle charges the flying capacitor C3 is the same as the flying capacitor charge direction in the immediately preceding odd-numbered (or even-numbered) read cycle. However, it is important in reducing the consumption of the battery module.

  (Disconnection Failure / Off Failure Determination) The disconnection failure / off failure determination in this embodiment can be performed based on the voltage of the battery module made immediately after the odd read cycle and the even read cycle. In addition, when a reset operation is performed immediately before the voltage reading of the battery module that is performed immediately after the odd read cycle and the even read cycle, a disconnection failure or an off failure is performed based on the voltage of the battery module that is performed immediately after the reset operation. Can be detected.

  That is, if the voltage of the battery module immediately after the above is a reverse voltage or the voltage of the flying capacitor C3 after reset less than a predetermined value, the voltage is normally read from the battery module immediately after the above. It can be determined that there is no.

  Another embodiment of the present invention will be described below with reference to FIG.

  This embodiment is different from the first embodiment shown in FIG. 1 in that the flying capacitor circuit 3 is composed of two flying capacitors C3 and C3 ′ connected in series, and the reset circuit 6 is the same as the reset circuit 6 in FIG. The first reset circuit 6x and the second reset circuit 6y are configured such that the first reset circuit 6x is connected in parallel to the flying capacitor C3, the second reset circuit 6y is connected in parallel to the flying capacitor C3 ′, and the flying capacitors C3 having substantially the same capacity are connected. , C3 ′ is connected to the reference power source Vref through the switch SSR23. The first reset circuit 6x includes a reset switch SSR26a (SW2) and a resistance element R26a, and the second reset circuit 6y includes a reset switch SSR26b (SW3) and a resistance element R26b.

  The operation of this circuit will be described. In this circuit, the multiplexer 2 stores the voltage ΔVs of the battery module in half in the flying capacitors C3 and C3 ′. Thereafter, the switches SSR21, SSR22, and SSRW23 are turned on, and the signal voltages of the flying capacitors C3 and C3 'are read out to the differential amplifier circuit 5. In this way, a potential that is higher by 0.5 ΔVs than the reference potential of the reference power source Vref and a potential that is lower by 0.5 ΔVs are applied to the pair of input ends of the differential amplifier circuit 5. The influence of the parasitic capacitance can be reduced, and the input voltage of the differential amplifier circuit 5 can be accurately swung to both sides using the reference voltage of the reference potential source Vref as an intermediate voltage value.

  In the circuit of FIG. 3, similarly to the first and second embodiments, the consumption of each battery module can be averaged and disconnection failure or off failure determination can be performed.

  Another embodiment of the present invention will be described below with reference to FIG.

  In this embodiment, in FIG. 3, the reset circuit 6 is constituted by the reset switch SSR26 and the current limiting resistor R20 shown in FIG. 1, and the output side sampling switch circuit 4 ′ is constituted by three output side sampling switches SSR21, SSR22, and SSR23. The differential amplifier circuit 5 'is provided with differential amplifier circuits 5a and 5b equivalent to the differential amplifier circuit 5 shown in FIG.

  The differential amplifier circuit 5a detects the stored voltage of the flying capacitor C3 through the output side sampling switches SSR21 and SSR22, and the differential amplifier circuit 5b detects the stored voltage of the flying capacitor C4 through the output side sampling switches SSR23 and SSR22.

  According to this circuit configuration, the voltages of the battery modules VB10, VB13, VB14, and VB17 are detected by the differential amplifier circuit 5a after charging the flying capacitor C3 in the same direction, and the voltages of the battery modules VB11, VB12, VB15, and VB16 are detected. Is detected by the differential amplifier circuit 5b after charging the flying capacitor C4 in the same direction. According to this circuit. The charging directions of the flying capacitors C3 and C4 can be aligned without a switching circuit. Also in this circuit, by adopting the same method as in the first embodiment, it is possible to reduce the disconnection failure, off failure, and consumption of the battery module.

1 Battery 2 Multiplexer 3 Flying Capacitor Circuit 4 Output Side Sampling Switch Circuit 5 Differential Amplifier Circuit

Claims (7)

A flying capacitor circuit having at least one flying capacitor;
Both ends of N (N> 2) battery modules that are connected in series to form an assembled battery are sequentially connected to both ends of the flying capacitor circuit for each of the battery modules, and the flying capacitors are generated by the voltages of the battery modules. A multiplexer that alternately charges the circuit for each voltage reading of the battery module; and
A differential amplifier circuit;
A pair of output side sampling switches for individually connecting a pair of input terminals of the differential amplifier circuit to both ends of the flying capacitor circuit;
With
In the method of driving a flying capacitor type assembled battery voltage detection circuit, wherein the multiplexer includes N + 1 input sampling switches each having one end connected to the highest potential end, each connection end, and the lowest potential end of each battery module. ,
The odd-numbered battery module voltages are sequentially read out to the flying capacitor circuit and output to the differential amplifier circuit, and then the odd-numbered battery module voltages are sequentially input to the flying capacitor circuit. A driving method of a flying capacitor type assembled battery voltage detecting circuit, wherein a reading cycle is performed by performing an even number reading cycle for reading and outputting to the differential amplifier circuit. In the driving method of the flying capacitor type assembled battery voltage detection circuit according to claim 1,
A flying capacitor type assembled battery voltage, wherein a disconnection failure is determined based on a read voltage of the first battery module of the odd read cycle and a read voltage of the first battery module of the even read cycle A detection circuit driving method. In the driving method of the flying capacitor type assembled battery voltage detection circuit according to claim 2,
A flying capacitor type assembled battery comprising a reset circuit that short-circuits the flying capacitor circuit and attenuates the stored voltage immediately before reading the voltage of the battery module at the head of each of the odd read cycle and the even read cycle Driving method of the voltage detection circuit. In the driving method of the flying capacitor type assembled battery voltage detection circuit according to any one of claims 1 to 3,
A flying capacitor type assembled battery voltage detection circuit that sequentially shifts the first battery module of the odd read cycle in each read cycle and the first battery module of the even read cycle in each read cycle. Driving method. A flying capacitor circuit having at least one flying capacitor;
Both ends of N (N> 2) battery modules that are connected in series to form an assembled battery are sequentially connected to both ends of the flying capacitor circuit for each of the battery modules, and the flying capacitors are generated by the voltages of the battery modules. A multiplexer that charges the circuit alternately or always with the same polarity for each voltage reading of the battery module;
A differential amplifier circuit;
A pair of output side sampling switches for individually connecting a pair of input terminals of the differential amplifier circuit to both ends of the flying capacitor circuit;
In a driving method of a flying capacitor type assembled battery voltage detection circuit comprising:
The voltage of each battery module is sequentially read out by the flying capacitor circuit and output to the differential amplifier circuit in each read cycle. M (M> N) battery module voltage read is performed every predetermined period. Has steps,
The voltage of the predetermined number of the battery modules is read a plurality of times by the plurality of voltage reading steps in each reading cycle,
The storage direction of the flying capacitor circuit according to the second voltage reading step of the predetermined battery module that is read a plurality of times in the read cycle,
A driving method of a flying capacitor type assembled battery voltage detection circuit, characterized in that it is set in the same direction as the storage direction of the flying capacitor in the immediately preceding voltage reading step. In the driving method of the flying capacitor type assembled battery voltage detection circuit according to claim 5,
A driving method of a flying capacitor type assembled battery voltage detection circuit, wherein the combination of the battery modules read a plurality of times in the one read cycle is sequentially changed. A flying capacitor circuit having at least one flying capacitor;
Both ends of N (N> 2) battery modules that are connected in series to form an assembled battery are sequentially connected to both ends of the flying capacitor circuit for each of the battery modules, and the flying capacitors are generated by the voltages of the battery modules. A multiplexer that alternately charges the circuit for each voltage reading of the battery module; and
A differential amplifier circuit;
A pair of output side sampling switches for individually connecting a pair of input terminals of the differential amplifier circuit to both ends of the flying capacitor circuit;
In a driving method of a flying capacitor type assembled battery voltage detection circuit comprising:
Each battery module sequentially reads out the voltage of each battery module to the flying capacitor circuit and outputs the voltage to the differential amplifier circuit. The read cycle of the battery module is performed for each predetermined period M (M> N) times. Has steps,
During each of the read cycles, all the odd-numbered battery modules are sequentially read out to the flying capacitor circuit and output to the differential amplifier circuit. The voltage is sequentially read out to the flying capacitor circuit, and the even-numbered read cycle is output to the differential amplifier circuit.
The storage direction of the flying capacitor circuit according to the second voltage reading step of the predetermined battery module that is read a plurality of times in the read cycle,
A driving method of a flying capacitor type assembled battery voltage detection circuit, wherein the combination of the battery modules read out a plurality of times is sequentially changed in the same direction as the storage direction of the flying capacitor in the immediately preceding voltage reading step.

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