JP2009189172A - Voltage detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, when detecting each voltage of battery cells B0-B7 constituting a battery pack 10, it is impossible to grasp a relative relationship of charging states between all the battery cells B0-B7 because of variations of an outflow/inflow current of the battery pack 10. <P>SOLUTION: A voltage of each battery cell B0-B3 is detected by a voltage detection circuit 24b. Simultaneously, a plurality of processing operations are performed while changing the battery cells B4-B7 subjected to voltage detection by a voltage detection circuit 24a. Consequently, it is possible to increase the number of battery cells which allows voltage detection simultaneously with each of the battery cells B0-B7, in proportion as the number of voltage detection circuits 24a, 24b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an assembled battery as a series connection body of a plurality of battery cells, and a plurality of voltages for detecting each voltage of a unit battery composed of one or a plurality of adjacent battery cells constituting the assembled battery. The present invention relates to an assembled battery voltage detection device including a detection circuit.

  For example, in Patent Document 1 below, the voltage of each secondary battery is sequentially detected by selectively connecting both electrodes of each secondary battery constituting the assembled battery to a pair of input terminals of a voltage detection circuit. A voltage detection device is described. Further, this document also describes that a discharge process for a high voltage secondary battery is performed by connecting a discharge circuit in parallel to the high voltage secondary battery in order to reduce the voltage difference between the secondary batteries. Has been. Thereby, the voltage dispersion | variation between secondary batteries can be reduced.

Note that there are other voltage detection devices described in, for example, Patent Document 2 below.
Japanese Patent Laid-Open No. 11-150877 JP 2002-315212 A

  By the way, in recent years, an assembled battery is used as a power feeding means of an in-vehicle motor in a hybrid vehicle or the like. In this case, when the vehicle is traveling, there may occur a situation in which the power required for the on-vehicle motor and the power supplied from the on-vehicle generator to the assembled battery vary greatly. For this reason, when the vehicle is traveling, the current flowing through the assembled battery varies greatly. On the other hand, at the time of charging / discharging of the secondary battery, a voltage drop corresponding to the internal resistance and charging / discharging current of the secondary battery occurs. For this reason, when detecting the voltages of a plurality of secondary batteries at different timings, the relative relationship between the state of charge of each other is grasped due to fluctuations in the voltage drop amount. I can't. For this reason, it cannot be grasped which secondary battery should be discharged by the discharge circuit.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide an assembled battery as a series connection body of a plurality of battery cells, one or a plurality of adjacent batteries constituting the assembled battery. An object of the present invention is to provide an assembled battery voltage detection device capable of more appropriately grasping the relative relationship between the state of charge of unit cells when detecting the voltage of each unit battery comprising cells.

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

  According to the first aspect of the present invention, for the assembled battery as a series connection body of a plurality of battery cells, for detecting each voltage of a unit battery comprising one or a plurality of adjacent battery cells constituting the assembled battery. In the assembled battery voltage detection apparatus including the plurality of voltage detection circuits, a voltage detection process is performed for detecting the voltages of the plurality of unit batteries constituting the assembled battery at the same time using the plurality of voltage detection circuits. A processing means is provided, and the voltage detection process includes a process of changing a unit battery whose voltage is detected at the same time as each of the unit batteries.

  In the above invention, for each unit battery constituting the assembled battery, by changing the unit battery whose voltage is detected at the same time, the number of unit batteries whose voltage is detected at the same time as each unit battery is changed. The number of voltage detection circuits can be increased. For this reason, the relative relationship of the charge condition of unit cells can be grasped more appropriately.

  The processing means detects each voltage of the selected unit cells by selectively connecting each of the plurality of voltage detection circuits to any one of the unit cells constituting the assembled battery. It is desirable to be a thing.

  According to a second aspect of the present invention, in the first aspect of the present invention, the voltage detection objects of the plurality of voltage detection circuits include a plurality of groups that do not include a common one of the plurality of unit cells. Any one of unit batteries is allocated.

  In order to detect the voltage of the unit battery by the voltage detection circuit, means for connecting them is required. For this reason, in order to be able to detect the voltage of the same unit battery with a plurality of voltage detection circuits, means for connecting the unit battery and each voltage detection circuit is required. On the other hand, in the said invention, since the voltage detection circuit which can be connected to arbitrary unit batteries can be made into one, the number of means to connect between a unit battery and a voltage detection circuit can be reduced as much as possible.

  According to a third aspect of the present invention, in the second aspect of the present invention, the plurality of groups are grouped so that unit cells adjacent to each other are the same group.

  In adjacent unit cells, the negative electrode terminal of the high-potential side unit cell and the positive electrode terminal of the low-potential side unit cell have the same potential. Therefore, when these adjacent unit cells are detected by the same voltage detection circuit, the means for connecting the positive terminal and the voltage detection circuit and the means for connecting the negative terminal and the voltage detection circuit are shared. can do. For this reason, in the said invention, the number of means to connect a unit battery and a voltage detection circuit can be reduced as much as possible.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the voltage detection processing is performed in another group detected at the same time as the voltage detection of each unit battery in each group. It includes a process of performing voltage detection of each unit battery and voltage detection of all the unit batteries of the other group at the same time by sequentially changing the unit batteries.

  In the said invention, the relative relationship of the charge condition of the unit battery which comprises an assembled battery can be grasped | ascertained with high precision.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, further comprising an equalizing unit that suppresses variations in voltage between the unit cells based on a voltage detection result by the voltage detection process. It is further provided with the feature.

  In the above invention, since the equalizing means is provided, the voltage detection result by the voltage detection process can be effectively used to suppress the voltage variation between the unit cells. For this reason, the merit of executing the voltage detection processing is particularly great.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the equalizing means is detected from a minimum value of the detected voltage among the plurality of unit batteries that are voltage detection targets at the same time. It is characterized by comprising a discharge control means for performing a discharge process for a voltage higher than a specified voltage.

  In the above invention, by providing the discharge control means, it is possible to reduce the voltage variation between the unit cells with a relatively simple configuration.

  According to a seventh aspect of the present invention, in the invention according to the sixth aspect, the processing means periodically performs a series of voltage detection processes including the plurality of processes, and the discharge control means is the periodic control. At the completion of each voltage detection process to be performed, the process according to this definition is executed by determining what performs the discharge process and does not perform the discharge process based on the voltage detection result in the voltage detection process It is characterized by that.

  In the above-described invention, it is possible to update and execute which unit battery is subjected to the discharge process every time the voltage detection process is performed periodically.

  The invention according to claim 8 is the invention according to claim 7, further comprising evaluation means for evaluating the reliability of the detection result based on the detection result of the voltage prior to the discharge process, and the reliability is low. If it is determined, the discharge process is prohibited.

  In the said invention, a discharge process can be performed more appropriately by providing the said evaluation means.

  According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the plurality of voltage detection circuits include two voltage detection circuits.

  In the above invention, by performing voltage detection with two voltage detection circuits, it is possible to realize the processing by the processing means while suppressing the number of hardware means as much as possible.

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

  FIG. 1 shows a system configuration according to the present embodiment.

  The illustrated assembled battery 10 constitutes a vehicle-mounted high-voltage battery, supplies power to the vehicle-mounted rotating machine, charges electric energy supplied from the vehicle-mounted rotating machine, and further includes a step-down converter (not illustrated). Power is supplied to the vehicle-mounted low-voltage battery. The assembled battery 10 is a series connection body of battery cells B1 to B7. Here, the battery cell Bi (i = 0 to 7) is a lithium secondary battery. In FIG. 1, the assembled battery 10 is schematically illustrated as a series connection body of eight battery cells B <b> 0 to B <b> 7, but actually a desired high voltage (for example, “288 V”) is realized. Therefore, the assembled battery 10 is composed of a series connection body of several tens of battery cells Bi.

  A voltage detection unit 20 is connected to the electrode of each battery cell Bi of the assembled battery 10, and voltage information at both ends of each battery cell Bi detected by the voltage detection unit 20 is a microcomputer constituting an in-vehicle low-voltage system. (Microcomputer 30).

  The voltage detection unit 20 includes wirings L0 to L8 connected to the electrodes of the battery cells Bi. Here, the wiring Lj (j = 0 to 7) is connected to the negative electrode of the battery cell Bj, and the wiring L (j + 1) is connected to the positive electrode of the battery cell Bj. These wirings L0 to L8 can be connected to the flying capacitors 22a and 22b via the multiplexer MPX. Specifically, the wirings L4 to L7 and the wirings L0 to L4 can be connected to the flying capacitors 22a and 22b, respectively. More specifically, the wirings L0 to L4 and the wirings L4 to L8 are set so that the electrodes of the flying capacitors connected to each other are different from each other. Specifically, the multiplexer MPX includes switching elements SW0 to SW3 and SW5 to SW8 connected to the wirings L0 to L3 and L5 to L8, respectively, and switching elements SW4a and SW4b connected to the wiring L4. Has been. Here, the switching element SW4b is for connecting the battery cell B3 to the flying capacitor 22b, and the switching element SW4a is for connecting the battery cell B4 to the flying capacitor 22a.

  These flying capacitors 22a and 22b can be connected to the voltage detection circuits 24a and 24b via the connection circuit SS. Here, each of the voltage detection circuits 24a and 24b includes a differential amplifier circuit. On the other hand, the connection circuit SS includes switching elements SA1 and SA2 for connecting a pair of electrodes of the flying capacitor 22a to a pair of input terminals of the voltage detection circuit 24a, and a pair of electrodes of the flying capacitor 22b as a pair of the voltage detection circuit 24b. Switching elements SB1 and SB2 for connection to the input terminal. The output signals of the voltage detection circuits 24a and 24b are taken into the microcomputer 30.

  The voltage detection unit 20 further includes a discharge circuit DC for discharging the electric charge of each battery cell Bi. Here, the discharge circuit DC includes a series connection body of a switching element 26 and a resistor 28 connected in parallel to each battery cell Bi. The multiplexer MPX, the connection circuit SS, and the discharge circuit DC are all operated by the microcomputer 30. Here, since the multiplexer MPX and the discharge circuit DC constitute a high voltage system, the switching element such as the multiplexer MPX is constituted by an insulating means such as a photo MOS relay. Instead of this, hardware means for operating the multiplexer MPX and the discharge circuit DC may be provided on the high voltage system side.

  In the present embodiment, by using the voltage detection circuits 24a and 24b, the voltage of the battery cell Bi is detected, and based on this, the discharge circuit DC is configured to suppress the voltage variation of the battery cell Bi constituting the assembled battery 10. To perform a discharge treatment. Here, with respect to the voltage detection process, the voltage of the battery cell Bi is detected for each of the battery cells Bi by a plurality of processes in which the battery cells whose voltages are detected at the same time are different from each other. In other words, simultaneously with each of the battery cells B4 to B7 connected to the voltage detection circuit 24a, the voltage of the battery cell Bi is detected by a plurality of processes in which the battery cells B0 to B3 connected to the voltage detection circuit 24b are different. To do.

  FIG. 2A shows voltage detection processing according to the present embodiment. Here, the circuit A and the circuit B are the voltage detection circuits 24a and 24b. Moreover, each voltage value V0-V7 is a voltage of battery cell B0-B7, respectively. Here, when the voltage detection circuit 24a detects each voltage of the battery cells B4 to B7 once each, the voltage detection circuit 24b performs two processes for detecting each voltage of the battery cells B0 to B3 once. These are provided as stage 1 and stage 2, respectively. That is, for example, in the first process of stage 1, the voltage V0 of the battery cell B0 and the voltage V4 of the battery cell B4 are detected simultaneously, and in the second process of stage 1, the voltage V1 of the battery cell B1 and the battery The voltage V5 of the cell B5 is detected at the same time. Here, in the stage 2, the battery cells Bi whose voltages are simultaneously detected in the stage 1 are not simultaneously detected.

  According to such setting, as shown in FIGS. 2B and 2C, the number of battery cells whose voltage is detected simultaneously with each battery cell Bi can be two. In other words, due to hardware limitations, since there are two voltage detection circuits 24a and 24b, the number of battery cells that can detect voltage simultaneously with each battery cell Bi is “1”, whereas the voltage detection processing is devised. By doing so, this number can be expanded. Thereby, even if the inflow / outflow current of the assembled battery 10 greatly fluctuates within the voltage detection processing period, the relative relationship between the charge states of all the battery cells constituting the assembled battery Bi is grasped in more detail. be able to.

  When the voltage is detected in this way, in the present embodiment, processing for discharging a high voltage is performed in order to suppress variation in the detected voltage. Specifically, as shown in FIG. 3, when the difference between the high-voltage battery cell and the high-voltage battery cell detected simultaneously exceeds a predetermined value α, the high-voltage battery cell is discharged. According to this discharge process, the variation of the battery cells B <b> 0 to B <b> 7 constituting the assembled battery 10 can be set to “4α” or less.

  FIG. 4 shows the procedure of the equalizing discharge process. This process is repeatedly executed by the microcomputer 30 or the like, for example, at a predetermined cycle.

  In this series of processes, first, in step S10, the multiplexer MPX is operated to connect the battery cell group shown in FIG. 2A to the current voltage detection target group to the flying capacitor. In subsequent step S12, the voltage detection circuits 24a and 24b are used to simultaneously detect the voltages Va and Vb of the battery cells connected thereto. That is, after operating the multiplexer MPX to disconnect between the flying capacitors 22a and 22b and the battery cell, the connection circuit SS is operated to connect the flying capacitors 22a and 22b to the voltage detection circuits 24a and 24b, respectively. Connecting. Then, the output signals of the voltage detection circuits 24 a and 24 b are taken into the microcomputer 30.

  In a succeeding step S14, it is determined whether or not the voltage Va detected by the voltage detection circuit 24a is larger than the voltage Vb detected by the voltage detection circuit 24b by a predetermined value α or more. This process is for determining whether or not to perform the discharge process on the battery cell that is the detection target of the voltage detection circuit 24a. If an affirmative determination is made in step S14, the cell discharge flag corresponding to this is turned on in order to discharge the battery cell detected by the voltage detection circuit 24a in step S16. On the other hand, if a negative determination is made in step S14, whether or not the voltage Vb detected by the voltage detection circuit 24b in step S18 is greater than the voltage Va detected by the voltage detection circuit 24a by a predetermined value α or more. Judge whether or not. This process is for determining whether or not to perform the discharge process for the battery cell to be detected by the voltage detection circuit 24b. If an affirmative determination is made in step S18, the cell discharge flag corresponding to this is turned on in order to discharge the battery cell detected by the voltage detection circuit 24b in step S20.

  When the processes in steps S16 and S20 are completed, it is determined in step S22 whether all stages, that is, all processes in stage 1 and stage 2 have been completed. If it is determined that the process has been completed, it is determined in step S24 whether or not the cell discharge flags of all the cells are on. This process evaluates the reliability of the voltage detection result obtained by the current series of voltage detection processes, that is, the stage 1 and stage 2 processes. That is, if the voltage detection process is appropriately performed, the discharge flag is not turned on for all the battery cells. For this reason, if all of the discharge flags are in the on state, it is considered that an abnormality has occurred due to the influence of noise or the like, and it is considered inappropriate to perform the discharge process according to the discharge flag at this time. For this reason, when it is determined that all the discharge flags are in the ON state, the discharge of all the battery cells is prohibited in step S26.

  On the other hand, when it is determined in step S24 that all the discharge flags are not turned on, in step S28, the battery cells are discharged for those for which the discharge flag is turned on. Here, if the discharge flag has been turned off for the discharge process that was previously performed in step S28, the discharge is stopped. On the other hand, as in the previous case, the discharge is continued for those in which the discharge flag is on this time. On the other hand, if the previous discharge process has not been performed and the current discharge flag is on, the discharge process is newly started.

  In addition, when the process of said step S26, S28 is completed, or when negative determination is made in step S22, this series of processes is once complete | finished.

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

  (1) When detecting the voltage of each battery cell using the voltage detection circuits 24a and 24b, for each battery cell Bi, two processes (stage 1, Stage 2) was performed. Thereby, the relative relationship of the charge condition of battery cells can be grasped more appropriately.

  (2) A plurality of groups (battery cells B <b> 0 to B <b> 3 and battery cells B <b> 4 to B <b> 7) that do not include common cells among the battery cells constituting the assembled battery 10 as voltage detection targets of the voltage detection circuits 24 a and 24 b. Allocate one of the following. Thereby, the number of means for connecting the battery cell and the voltage detection circuits 24a and 24b can be reduced as much as possible.

  (3) The voltage detection objects of the voltage detection circuits 24a and 24b are grouped such that adjacent battery cells are in the same group (battery cells B0 to B3 and battery cells B4 to B7). Thereby, the number of means for connecting the battery cells and the voltage detection circuits 24a and 24b can be reduced as much as possible.

  (4) Among the pair of battery cells to be subjected to voltage detection at the same time, a discharge process was performed on a battery whose higher value than the lower value of the detected voltage value is higher than the predetermined value α. Thereby, the voltage dispersion between battery cells can be reduced with a relatively simple configuration.

  (5) At the completion of each voltage detection process (stage 1 and stage 2) that is performed periodically, based on the voltage detection result in the voltage detection process, what performs the discharge process and what does not perform the discharge process The process according to this rule was executed. Thereby, it is possible to update and execute which battery cell is subjected to the discharge process every time the voltage detection process is performed periodically.

  (6) Prior to the discharge process, if it is determined that the reliability of the detection result is low based on the voltage detection result (the state of the discharge flag) (when all the discharge flags are on), the discharge process is prohibited. did. Thereby, discharge processing can be performed more appropriately.

  (7) Two voltage detection circuits 24a and 24b are provided to perform voltage detection processing. Thereby, it is possible to execute a voltage detection process including a plurality of stages while suppressing the number of hardware means as much as possible.

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

  In the first embodiment, two processes (stage 1 and stage 2) for changing the battery cell whose voltage is detected by the voltage detection circuit 24b at the same time as any battery cell to be detected by the voltage detection circuit 24a. A voltage detection process was performed. And in this case, it was shown that the variation in voltage of the battery cells constituting the assembled battery 10 can be suppressed to “4α” or less by the discharge treatment. However, according to such a process, the voltage variation of a battery cell will increase when the number of the battery cells which comprise the assembled battery 10 increases. Here, by reducing the predetermined value α, it is possible to some extent to reduce the voltage variation of the battery cells. However, because the predetermined value α cannot be excessively reduced due to problems such as detection accuracy, the predetermined value α has a lower limit. Therefore, in the voltage detection process according to the first embodiment, it is inevitable that voltage variation increases due to an increase in the number of battery cells constituting the assembled battery 10.

  Therefore, in the present embodiment, as shown in FIG. 5A, another group detected at the same time as the voltage detection of each of the battery cells B4 to B7 of the group that is the voltage detection target of the voltage detection circuit 24a. By sequentially changing the battery cells B0 to B3, voltage detection of each of the battery cells B4 to B7 and all voltage detection of the battery cells B0 to B3 are performed simultaneously. In this way, by detecting the voltage of all the battery cells of each group simultaneously with the voltage detection of each battery cell of each group, the voltage variation of the battery cells constituting the assembled battery 10 is set to a predetermined value α. “2” times or less. This is due to the following reason.

  Assuming that the battery cell B0-B7 having the lowest voltage is in the group of battery cells B0-B3, each of the battery cells B4-B7 is detected at the same time as the battery cell with the lowest voltage. Have the opportunity to For this reason, by performing a discharge process based on this, the deviation | shift amount of each voltage of battery cell B4-B7 can be made into below predetermined value (alpha). On the other hand, all of the battery cells B0 to B3 have an opportunity of voltage detection simultaneously with all of the battery cells B4 to B7. For this reason, by performing voltage detection based on this, the maximum value of the voltage of the battery cells B0 to B3 is limited to the value obtained by adding the predetermined value α to the voltage of the battery cells B4 to B7. Thereby, as shown in FIG.5 (b), the voltage of battery cell B0-B7 will enter between the value higher only by "2 (alpha)" from the minimum value and the minimum value.

  According to this embodiment described above, in addition to the effects (2) to (7) of the first embodiment, the following effects can be obtained.

  (8) By sequentially changing another group of battery cells detected simultaneously with the voltage detection of each battery cell of each group, each of the voltage detection of each battery cell and the voltage detection of all the battery cells of another group And went at the same time. Thereby, regardless of the increase in the number of battery cells constituting the assembled battery 10, the voltage variation of the battery cells can be made to be “2” times or less of the predetermined value α.

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

  In the first embodiment, as the number of the assembled batteries 10 is increased, the variation in voltage is not only increased, but one cycle of the voltage detection processing time is extended. Therefore, in the present embodiment, it is considered to increase the hardware so that the time of one cycle of the voltage detection process satisfies the request.

  Here, among the number n of battery cells Bi constituting the assembled battery 10, the voltage detection restriction time T per stage, the voltage detection time Tc of one battery cell, and the number m of flying capacitors, The following relationship holds.

Tc × n / m ≦ T (c1)
The minimum value of the integer m satisfying the relationship of the above formula (c1) is the minimum value of the number of flying capacitors and voltage detection circuits necessary for setting the time required for each stage as the voltage detection constraint time T. At this time, the number k of the switching elements configuring the multiplexer MPX and the connection circuit SS is “k = (n + m) + (m × 2)”.

  Thus, the hardware can be designed so that one cycle of the voltage detection processing time satisfies the requirement. That is, the number of stages NS for setting the voltage variation between the battery cells within an allowable range is determined by the number n of battery cells constituting the assembled battery 10. Thereby, the voltage detection restriction time T per stage is determined as “T = TT / NS” from the restriction time TT of one cycle. From this, the necessary number of voltage detection circuits and flying capacitors can be calculated based on the relationship of the above formula (c1).

  FIG. 6 shows a system configuration example designed in this way. In FIG. 6, members corresponding to those shown in FIG. 1 are given the same reference numerals for the sake of convenience.

  In FIG. 6, the battery cells constituting the assembled battery 10 are grouped into three groups of battery cells B0 to B2, battery cells B3 to B5, and battery cells B6 and B7. The voltages in these groups are detected by the voltage detection circuits 24c, 24b, and 24a by being applied to the flying capacitors 22c, 22b, and 22a, respectively.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects according to the first embodiment and the effects according to the second embodiment. Become.

  (8) By designing the voltage detection unit 20 according to the request for one cycle of the voltage detection process, a single voltage detection process can be executed within the required time.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In each of the above embodiments, the battery cell Bi to be discharged is updated when a series of voltage detection processes including a plurality of processes (stages) is completed. However, the discharge control unit is not limited to this. For example, when a deviation exceeding a predetermined value α occurs between battery cells that are subjected to voltage comparison at the same time, a discharge process is performed until the deviation amount is equal to or less than the predetermined value α. You may change the battery cell to perform.

  A series of voltage detection processes including a plurality of processes (stages) is not limited to the above. For example, in the first embodiment, the voltage detection process may be configured in three stages. In this case, the voltage variation between the battery cells Bi can be further suppressed as compared with the first embodiment.

  -The number of voltage detection circuits is not limited to two or three. By increasing the number of voltage detection circuits, the number of parts increases, but the voltage detection processing time is shortened. However, the number of voltage detection circuits is preferably smaller than the number of voltage detection targets (battery cells), and more preferably “½” or less of the number of voltage detection targets.

  The grouping of the battery cells to be detected by each of the plurality of voltage detection circuits is not limited to the grouping so that the battery cells Bi and B (i + 1) adjacent to each other are in the same group. For example, B0, B2, B4, and B6 and B1, B3, B5, and B7 may be grouped.

  The grouping of the battery cells to be detected by each of the plurality of voltage detection circuits is not limited to those that do not include the common ones, but may be redundant groupings that include the common ones.

  -The equalization process means which suppresses the voltage dispersion | variation of each battery cell Bi of an assembled battery is not restricted to what performs the said equalization discharge process. For example, it is good also as a process which charges the battery cell Bi with a high voltage to the battery cell with a low voltage.

  In the above embodiment, the voltages of all the battery cells Bi constituting the assembled battery 10 are detected by the voltage detection circuits 24a and 24b or the voltage detection circuits 24a, 24b and 24c. However, the present invention is not limited to this. . For example, each of a plurality of battery cells Bi adjacent to each other may be used as a block, and each block may have the configuration illustrated in FIG. 1 or FIG.

  In each of the above embodiments, the voltage detection target by the voltage detection circuit is the battery cell Bi, but is not limited thereto. For example, the voltage may be detected for each block composed of a plurality of battery cells adjacent to each other.

  -The battery cell is not limited to a lithium secondary battery. For example, a nickel metal hydride secondary battery may be used.

  The voltage detection device for the assembled battery is not limited to that mounted on a hybrid vehicle, and may be mounted on an electric vehicle, for example. Furthermore, it is not restricted to what is mounted in a vehicle. Even in such a case, when the voltage of each unit battery (either a single battery cell or a plurality of adjacent battery cells) is detected when the assembled battery is charged and discharged, the above invention The effects of the above can be particularly suitably achieved.

1 is a system configuration diagram according to a first embodiment. FIG. The figure which shows the aspect of the voltage detection process concerning the embodiment. The figure which shows the equalization discharge process concerning the embodiment. The flowchart which shows the process sequence of the equalization discharge process concerning the embodiment. The figure which shows the aspect of the voltage detection process concerning 2nd Embodiment. The system block diagram concerning 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Assembly battery, 20 ... Voltage detection unit, 22a, 22b, 22c ... Flying capacitor, 24a, 24b, 24c ... Voltage detection circuit, 30 ... Microcomputer.

Claims (9)

The assembled battery as a series connection body of a plurality of battery cells includes a plurality of voltage detection circuits for detecting each voltage of a unit battery composed of one or a plurality of adjacent battery cells constituting the assembled battery. In an assembled battery voltage detection device,
A processing means for performing a voltage detection process for detecting each voltage of a plurality of unit batteries constituting the assembled battery at the same time using the plurality of voltage detection circuits;
The voltage detection process includes a process of changing a unit battery whose voltage is detected at the same time for each of the unit batteries.   The unit battery of any one of a plurality of groups not including a common one among the plurality of unit batteries is allocated as a voltage detection target of each of the plurality of voltage detection circuits. Item 4. A voltage detection apparatus for an assembled battery according to Item 1.   3. The assembled battery voltage detection apparatus according to claim 2, wherein the plurality of groups are grouped so that unit batteries adjacent to each other are in the same group.   The voltage detection process sequentially changes the unit batteries of another group detected at the same time as the voltage detection of each unit battery of each group, thereby detecting the voltage of each unit battery and all of the other groups. The assembled battery voltage detection device according to any one of claims 1 to 3, further comprising a process of simultaneously performing each unit battery voltage detection.   The voltage of the assembled battery according to any one of claims 1 to 4, further comprising an equalizing unit that suppresses variation in voltage between the unit batteries based on a voltage detection result obtained by the voltage detection process. Detection device.   The equalizing means is a discharge control means for performing a discharge process on a plurality of unit batteries that are subject to voltage detection at the same time and whose detected voltage is higher than a minimum value than the minimum value of the detected voltage. The assembled-battery voltage detection device according to claim 5, comprising: The processing means periodically performs a series of voltage detection processes including the plurality of processes.
The discharge control means, upon completion of each periodic voltage detection process, based on the voltage detection result in the voltage detection process, to determine what to perform the discharge process and what to not perform the discharge process, The assembled battery voltage detection device according to claim 6, wherein processing according to this rule is executed. Prior to the discharge process, further comprising an evaluation means for evaluating the reliability of the detection result based on the detection result of the voltage,
The assembled battery voltage detection device according to claim 7, wherein when it is determined that the reliability is low, the discharge process is prohibited.   The assembled battery voltage detection device according to any one of claims 1 to 8, wherein the plurality of voltage detection circuits includes two voltage detection circuits.

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