JP2014096918A - Control device for battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a battery pack in which capacity adjustment can be performed in a short time and with high efficiency by active balancing.SOLUTION: In a battery pack which is formed by connecting a plurality of cells in series, for each of cells and/or modules to perform charge moving thereon, a charge moving amount and a charge input/output direction are calculated while considering a present charging state and a charge moving loss in the case where an electric charge is inputted/outputted. On the basis of the calculated charge moving amount and the charge input/output direction, the cell and/or the module to perform charge moving thereon is set and regarding the set cell and/or module, charge moving processing is executed. Prior to executing the charge moving processing, a current value is predicted which flows to a charge moving circuit in the case where the charge moving processing is executed. When the predicted current value is equal to or more than a predetermined threshold value, the current value is limited to be less than the threshold value.

Description

  The present invention relates to a control device for an assembled battery.

  As a method of connecting a plurality of cells in series and adjusting the capacity of an assembled battery that is modularized every predetermined number, active balancing is known in which charge transfer is performed between cells constituting each assembled battery or between modules. (For example, refer to Patent Document 1).

JP 2005-521363 A

  However, the active balancing disclosed in Patent Document 1 described above has the following problems.

  That is, in the active balancing disclosed in Patent Document 1, capacity variation is measured, and capacity adjustment is performed based on the measured capacity variation. Therefore, it is necessary to accurately calculate the capacity variation. Therefore, it is necessary to repeatedly perform charge transfer for capacitance adjustment and capacitance variation between cells. For this reason, if the amount of charge transfer during charge transfer is reduced, the frequency of measurement of capacity variation between cells increases, and as a result, the time required for capacity adjustment increases. is there. In particular, when measuring the variation in capacity between cells, it is necessary to measure the voltage and SOC of each cell with high accuracy. It is necessary to measure the voltage and SOC after waiting. Therefore, if the frequency of measuring the capacity variation increases, the time during which charge transfer for capacity adjustment is stopped becomes longer. As a result, capacity adjustment is performed. It takes a long time to complete.

  On the other hand, when the amount of charge transfer for capacity adjustment is increased, a chattering phenomenon that repeats charging and discharging occurs near the target voltage or the target SOC, and the time required for capacity adjustment becomes longer due to the chattering phenomenon. There is a problem of becoming. In particular, such a chattering phenomenon becomes more prominent when charge transfer is performed by active balancing at the same time between cells and between modules. Furthermore, since the efficiency of charge transfer between cells or between modules is not 100%, if the time required for capacity adjustment becomes longer due to chattering, charge transfer is unnecessarily performed. This also causes a problem that the charge transfer efficiency is lowered.

  The problem to be solved by the present invention is to provide an assembled battery control device capable of performing capacity adjustment by active balancing in a short time and with high efficiency.

  The present invention considers the current charge state and charge transfer loss when charge is input / output for each cell and / or each module that performs charge transfer in an assembled battery formed by connecting a plurality of cells in series. The charge transfer amount and the charge input / output direction are calculated, and the cell and / or module for performing charge transfer is set based on the calculated charge transfer amount and the charge input / output direction, and the set cell and / or For the module, the charge transfer process is executed, and before the charge transfer process is executed, the current value flowing through the charge transfer circuit when the charge transfer process is executed is predicted, and the predicted current value is equal to or greater than a predetermined threshold value. In such a case, the problem is solved by limiting the current value to be less than the threshold value.

  According to the present invention, the charge transfer amount and the charge input / output direction are calculated in consideration of the current capacity and charge transfer loss for each cell and / or each module that performs charge transfer. Since cells and / or modules that perform charge transfer are set, capacity adjustment by active balancing can be performed in a short time and with high efficiency.

FIG. 1 is a configuration diagram illustrating an assembled battery system according to the present embodiment. FIG. 2 is a diagram illustrating a specific configuration of the cell balancing circuit and the module balancing circuit according to the present embodiment. FIG. 3 is a diagram for explaining cell balancing according to the present embodiment. FIG. 4 is a diagram for explaining cell balancing according to the present embodiment. FIG. 5 is a block diagram illustrating a configuration of the control device 10. 6 (A) to 6 (C) are diagrams for explaining the outline of each of the method for performing only cell balancing, the method for performing only module balancing, and the method for performing cell balancing and module balancing at the same time. FIG. 7 is a schematic diagram showing cell balancing according to the present embodiment. FIG. 8 is a diagram for explaining charge transfer between the cell and the module. FIG. 9 is a flowchart showing temporary calculation processing during cell balancing. FIG. 10 is a diagram for explaining an example of a method for setting the order of cells for performing cell balancing. FIG. 11 is a diagram for explaining an example of a method for setting the order of cells for performing cell balancing. FIG. 12 is a diagram for explaining an example of a method for setting the order of cells for performing cell balancing. FIG. 13 is a schematic diagram illustrating module balancing according to the present embodiment. FIG. 14 is a flowchart showing temporary calculation processing during module balancing. FIG. 15 is a schematic diagram illustrating module balancing according to the present embodiment. FIG. 16 is a flowchart showing temporary calculation processing at the time of cell-module balancing. FIG. 17 is a diagram illustrating an example of a current flowing through the cell balancing circuit and the module balancing circuit according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Configuration of assembled battery system>
FIG. 1 is a configuration diagram illustrating an assembled battery system according to the present embodiment. As shown in FIG. 1, the assembled battery system according to this embodiment includes six modules M1 to M6. Among these modules M1 to M6, the module M1 is composed of 16 cells C1 to C16, and these cells C1 to C16 are connected in series. Similarly, each of the modules M2 to M6 includes 16 cells C17 to C32, C33 to C48, C49 to C64, C65 to C80, and C81 to C96 connected in series. As shown in FIG. 1, the modules M1 to M6 are connected in series with each other, whereby 96 cells are connected in series to form an assembled battery. In addition, in this embodiment, as shown in FIG. 1, the assembled battery which consists of 96 cells modularized by the six modules M1-M6 was illustrated, However, It is specifically limited to such a structure. is not.

  In addition, the assembled battery system according to the present embodiment includes a control device 10, and the control device 10 includes cell balancing circuits ACB1 to ACB6 for performing cell balancing of the modules M1 to M6 and between the modules M1 to M6. By controlling the module balancing circuits MMB12, MMB23, MMB25, MMB45, and MMB56 for performing module balancing, capacity adjustment by active balancing is performed between cells and modules constituting the assembled battery. A specific capacity adjustment method will be described later.

  Furthermore, the assembled battery system according to the present embodiment includes a current sensor 20 for detecting a current value flowing in 96 cells C1 to C96, and the current value detected by the current sensor 20 is the control device 10. Are transmitted at predetermined intervals. Moreover, the temperature sensor 30 for measuring the temperature of each module M1-M6 is provided in the vicinity of each module M1-M6, and the temperature of each module M1-M6 measured by each temperature sensor 30 is as follows. It is transmitted to the control device 10 at a predetermined interval.

  FIG. 2 shows specific configurations of the cell balancing circuit and the module balancing circuit. FIG. 2 shows only the modules M1 to M3 and the cell balancing circuit and the module balancing circuit related to the modules M1 to M3 among the modules M1 to M6 constituting the assembled battery. In FIG. 2, some of the cells constituting each of the modules M1 to M3 and the corresponding circuit configuration are omitted.

  Here, exemplifying the cell balancing circuit ACB1, the cell balancing circuit ACB1 adjusts the capacity between the cells C1 to C16 constituting the module M1 and the module M1, that is, cell balancing (between the cell and the module). Is a circuit for performing the capacitance adjustment. As shown in FIG. 2, the cell balancing circuit ACB1 includes switches S1 to S20, a diode D1, and a transformer T11.

Hereinafter, cell balancing executed by the cell balancing circuit ACB1 will be described. Note that the cell balancing is executed by controlling the switches S1 to S20 constituting the cell balancing circuit ACB1 by the control device 10 (see FIG. 1). For example, when discharging from the cell C2 constituting the module M1 to the module M1, as shown in FIG. 3, the switches S2, S3, S18, and S19 are closed, and the switch S20 is controlled to be opened and closed. The cell C2 is discharged, and the electric charge output by the discharge of the cell C2 is converted into electric charge for charging the module M1 through the transformer T11, whereby the module M1 (all cells C1 constituting the module M1) is converted. To C16) will be charged. Here, the voltage of the cell C2 is V _{cell_2} , the discharge current from the cell C2 is I _{cell_2} , the voltage of the entire module M1 is V _{module_1} , the charging current of the module M1 is I _{module_1,} and the current flows in the charging direction. Is positive, and conversely, when the current flows in the discharge direction is negative, the relationship of the following formula (1) is established.
η × V _{cell — 2} × I _cell — ₂ = −V _module — 1 × I _{module —} 1 (1)
Note that η represents the charge transfer efficiency of the transformer T11.

Alternatively, on the contrary, when the cell C2 constituting the module M1 is charged from the module M1, the switches S2, S3, S18, and S19 are closed (as shown in FIG. 4). By controlling the opening and closing of the switch S20 with the closing direction as the reverse direction, the charge output from the module M1 is charged into the cell C2 via the transformer T11. In this case, the relationship of the following formula (2) is established.
V _{cell — 2} × I _cell — ₂ = −η × V _{module — 1} × I _{module — 1} (2)

  Thus, in the present embodiment, the control device 10 (see FIG. 1) configures the module M1 by closing the switches S2, S3, S18, and S19 and controlling the switch S20 to open and close in the cell balancing circuit ACB1. The charge can be transferred from the cell C2 to the module M1 or from the module M1 to the cell C2. In this embodiment, cell balancing is performed in this way.

  Of the switches constituting the cell balancing circuit ACB1, the switches S1 to S17 correspond to switches for performing cell balancing. Therefore, as shown in FIGS. 2 and 3, when cell balancing is performed between the cell C2 and the module M1, the switches S2 and S3 are closed, but for example, between the cell C1 and the module M1. When cell balancing is executed, the switches S1 and S2 may be closed. Similarly, in the case of the cell C3, the switches S3 and S4 are closed, and in the case of the cell C4, the switches S4 and S5 may be closed, and the corresponding switches are also applied to the cells C5 to C16. (Switches S5 to S17) may be closed. The switches S18 and S19 are switches for controlling the direction of charge transfer. As shown in FIGS. 3 and 4, each of the cells C1 to C19 is controlled by controlling the switches S18 and S19 according to the desired charge direction. The C16 can be discharged to the module M1, or conversely, the cells C1 to C16 can be charged from the module M1. Furthermore, the switch S20 is a switch used when performing charge transfer through the transformer T11 by opening / closing control.

  Returning to FIG. 2, similarly to the module M1 described above, the module M2 also includes a cell balancing circuit ACB2, which is a circuit for performing cell balancing between the cells M17 to C32 constituting the module M2 and the module M2. As shown in FIG. 2, the cell balancing circuit ACB2 includes switches S21 to S40, a diode D2, and a transformer T22, similar to the cell balancing circuit ACB1 corresponding to the module M1 described above. In the same manner as described above, the control device 10 (see FIG. 1) controls the switches S21 to S40 constituting the cell balancing circuit ACB2, thereby causing the cells C17 to C32 constituting the module M2 and the module M2 to Cell balancing for transferring charges between the two is performed.

  Further, similarly to the modules M1 and M2 described above, the module M3 also includes a cell balancing circuit ACB3 that is a circuit for performing cell balancing between the cells C33 to C48 constituting the module M3 and the module M3. As shown in FIG. 2, the cell balancing circuit ACB3 includes switches S41 to S60, a diode D3, and a transformer T33, similarly to the cell balancing circuits ACB1 and ACB2 corresponding to the module M1 described above. In the same manner as described above, the control device 10 (see FIG. 1) controls the switches S41 to S60 that constitute the cell balancing circuit ACB3, whereby the cells C33 to C48 that constitute the module M3, the module M3, Cell balancing for transferring charges between the two is performed.

  Further, as shown in FIG. 1, the modules M4 to M6 are also circuits for performing cell balancing between each module constituting each module and each module, similarly to the modules M1 to M3 described above. The cell balancing circuits ACB4 to ACB6 are provided, and the cell balancing circuits ACB4 to ACB6 have the same configuration as the cell balancing circuits ACB1 to ACB3 described above, and operate in the same manner.

  In addition to the cell balancing circuits ACB1 to ACB6 described above, the assembled battery system of this embodiment includes a module balancing circuit MMB12 for performing module balancing between the modules M1 to M6, as shown in FIGS. , MMB23, MMB25, MMB45, and MMB56. For example, the module balancing circuit MMB12 is exemplified. The module balancing circuit MMB12 is a circuit for performing capacity adjustment between the module M1 and the module M2, that is, module balancing (capacitance adjustment between modules). As shown in FIG. 2, the module balancing circuit MMB12 includes switches S121 and S122 and a transformer T12.

  The capacity adjustment method between the module M1 and the module M2 by the module balancing circuit MMB12, that is, the module balancing method is the same as the cell balancing described above, and the specific capacity adjustment method is as follows. It is. The module balancing is executed by the control device 10 (see FIG. 1) being controlled to open and close the switches S121 and S122 that constitute the module balancing circuit MMB12.

  That is, the module M1 (that is, all the cells C1 to C16 constituting the module M1) is discharged to the module M2 (that is, all the cells C17 to C32 constituting the module M2), and the module M1 is changed to the module M2. When the charge is moved, for example, the switch S122 is closed and the switch S121 corresponding to the module M1 is controlled to be opened and closed, so that the charge is transferred from the module M1 to the module M2. Or, conversely, when discharging from the module M2 to the module M1 and transferring the charge from the module M2 to the module M1, for example, the switch S121 is closed and the switch S122 corresponding to the module M2 is opened and closed. By controlling, charge is transferred from the module M2 to the module M1.

  Similarly, as shown in FIGS. 1 and 2, the module balancing circuit MMB23 is a circuit for performing module balancing between the module M2 and the module M3. Similarly to the module balancing circuit MMB12 described above, the switch S231 is used. , S232, and a transformer T23. In the same manner as described above, the control device 10 (see FIG. 1) controls the switches S231 and S232 that constitute the module balancing circuit MMB23, whereby the module M2 (that is, all the cells C17 to C17 that constitute the module M2). C32) and module balancing for charge transfer between the module M3 (that is, all the cells C33 to C48 constituting the module M3) are performed.

  Similarly to the module balancing circuits MMB12 and MMB23 described above, as shown in FIG. 1, the module balancing circuits MMB45 and MMB56 are also between the modules M4 and M5 and between the modules M5 and M6, respectively. This is a circuit for performing module balancing, and the module balancing circuits MMB45 and MMB56 have the same configuration as the module balancing circuits MMB12 and MMB23 described above, and operate in the same manner.

  Further, as shown in FIG. 1, a module balancing circuit MMB25, which is a circuit for performing module balancing between the modules M2 and M5, is provided between the module M2 and the module M5. As shown in FIG. 2, the module balancing circuit MMB25 includes switches S251 and S252 and a transformer T25, one of which is connected to the module M2 via the transformer T25, and the other is a module M5 (not shown). Accordingly, module balancing is performed between the modules M2 and M5 in the same manner as the module balancing circuits MMB12 and MMB23 described above.

  Thus, in the assembled battery system of the present embodiment, as shown in FIG. 1, the modules M1 to M3 are module balanced by the module balancing circuits MMB12 and MMB23, while the modules M4 to M3 In M6, module balancing is performed by module balancing circuits MMB45 and MMB56. In addition, the assembled battery system according to the present embodiment further includes a module balancing circuit MMB25 for performing module balancing between the modules M2 and M5, whereby all the components of the assembled battery system according to the present embodiment are configured. The modules M1 to M6 are configured to perform capacity adjustment by active balancing.

  As described above, the battery pack system according to the present embodiment includes the cell balancing circuits ACB1 to ACB6 and the module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25 as shown in FIG. 10 to control the cells C1 to C96 constituting the modules M1 to M6, cell balancing for adjusting capacity between the modules M1 to M6, and module balancing for adjusting capacity between the modules M1 to M6. Can be executed.

  In this embodiment, such cell balancing and module balancing are performed by controlling the cell balancing circuits ACB1 to ACB6 and the module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25 by the control device 10 shown in FIG. It is executed by. Here, FIG. 5 is a block diagram illustrating a configuration of the control device 10.

  As shown in FIG. 5, the control device 10 includes a charge transfer condition setting unit 11, a current prediction control unit 12, and an SOC calculation unit 13.

  The SOC calculation unit 13 calculates the SOC (State of Charge) of each of the cells C1 to C96 constituting the assembled battery and the SOC of each of the modules M1 to M6. Specifically, the SOC calculation unit 13 determines the terminal voltage of each of the cells C1 to C96, the current value of the assembled battery detected by the current sensor 20 shown in FIG. 1, and each temperature measured by each temperature sensor 30 shown in FIG. Based on the temperatures of the modules M1 to M6 and the current values flowing through the cells C1 to C96 predicted by the current prediction control unit 12 described later, the SOCs of the cells C1 to C96 and the SOCs of the modules M1 to M6 are determined. calculate. In the present embodiment, the SOC of each module M1 to M6 can be set, for example, to the average value of the SOC of each cell constituting each module M1 to M6 as the SOC of each module M1 to M6.

  The charge transfer condition setting unit 11 is a condition for performing charge transfer by cell balancing and module balancing based on the SOCs of the cells C1 to C96 calculated by the SOC calculation unit 13 and the SOCs of the modules M1 to M6. Set. A method for setting conditions for executing charge transfer will be described later.

The current prediction control unit 12 determines the value of the current flowing through each of the cells C1 to C96, the cell balancing circuits ACB1 to ACB6, and module balancing based on the conditions for executing the charge transfer set by the charge transfer condition setting unit 11 A current value flowing through the circuits MMB12, MMB23, MMB45, MMB56, and MMB25 is predicted. As a result of predicting the current value, when the current value flowing through the wiring constituting each circuit is less than the predetermined threshold value I _LIM , based on the charge transfer condition set by the charge transfer condition setting unit 11, The cell balancing circuits ACB1 to ACB6 and the module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25 are controlled to execute the above-described cell lavancing and / or module balancing. Alternatively, as a result of predicting the current value, when the current value flowing in a specific wiring among the wirings constituting each circuit is equal to or greater than a predetermined threshold value I _LIM , when performing cell balancing and / or module balancing The process of limiting the current value is executed. A specific processing method in the process of limiting the current value will be described later.

  In the present embodiment, the SOC calculation processing of each cell by the SOC calculation unit 13, the processing for setting conditions for executing charge transfer by the charge transfer condition setting unit 11, and the cell by the current prediction control unit 12 The process of executing lavancing and / or module balancing and the process of limiting the current value are repeatedly executed at predetermined intervals.

  Next, a method for performing capacity adjustment by active balancing in the present embodiment will be described in detail. In the assembled battery system of the present embodiment, the following three modes can be cited as a method for performing capacity adjustment by active balancing. That is, there are three modes: (A) a method that performs only cell balancing, (B) a method that performs only module balancing, and (C) a method that performs cell balancing and module balancing simultaneously.

  And, for example, as shown in FIGS. 6A to 6C, in a situation where two modules composed of a plurality of cells are illustrated, between the cells constituting each module in a state before capacity adjustment. The SOC varies, and furthermore, the SOC between modules (the ratio of the total current capacity of all cells constituting the module to the sum of the maximum capacities of all cells constituting the module) also varies. First, as shown in FIG. 6 (A), in the method of performing only (A) cell balancing, although the SOC between cells constituting each module is equal, the SOC between each module is , Will remain scattered.

  In addition, as shown in FIG. 6B, in the method of performing only (B) module balancing, the SOC between the modules is equal, but the SOC between the cells remains varied.

  On the other hand, as shown in FIG. 6C, in the method of performing (C) cell balancing and module balancing at the same time, both the SOC between cells and the SOC between modules can be made equal. .

  In the present embodiment, after the method (A) is performed, the method (B) is performed, or the methods are performed in the reverse order, so that the method (C) is performed. Similar to the method, the SOC between cells and the SOC between modules can be equalized. However, according to the method (C), after the method (A) is executed, the capacity adjustment time can be shortened as compared with the case where the method (B) is executed. This is desirable because it is possible.

  In the following, (A) a method of performing only cell balancing, (B) a method of performing only module balancing, and (C) a method of performing cell balancing and module balancing simultaneously will be described.

<(A) Method of performing only cell balancing>
First, a specific capacity adjustment condition setting method in the method of (A) performing only cell balancing will be described. In the cell balancing according to the present embodiment, as described above, charge transfer is performed between each module constituting the module to be subjected to cell balancing and the module, thereby performing capacity adjustment in the module. It is.

Here, in FIG. 7, the schematic diagram which shows the cell balancing which concerns on this embodiment is shown. In FIG. 7, among the modules M1 to M6 constituting the assembled battery, the first module M1 is designated as module # 1, and similarly, the second to sixth modules M2 to M6 are designated as module # 2. ˜ # 6 schematically shows cell balancing performed in the module #j, which is the jth module. Then, as shown in FIG. 7, in the following, the first cell # 1 constituting the module #j is denoted by y _{1 as the} amount of charge transferred from the module #j, and the i-th (i = 1 to n _Mj , Where n _Mj is the number of cells in the jth module) cell #i, and y _i is the amount of charge transferred from module #j, and the charge transferred from module #j to n _Mjth cell #n _{Mj Let the} quantity be _ynMj .

Here, consider a case where charge transfer is performed between the cell #i constituting the module #j and the module #j. In the following, as shown in FIG. 8, the amount of charge moving from module #j to cell #i is y _i , the charge transfer efficiency is η _i (η _i <1), and module # before charge transfer is Assume that the capacity of j is Q _Mj and the capacity of the cell #i before charge transfer is Q _i . The sign of the charge amount y _i is defined as positive when the discharge is performed from the module #j to the cell #i, and conversely, is defined as negative when the discharge is performed from the cell #i to the module #j. In this case, the following relationship is established.

（なお、上記式（３）において、Ｑ_Ｍｊ’ は、電荷移動後のモジュール＃ｊの容量を表し、Ｑ_ｉ’は、電荷移動後のセル＃ｉの容量を表す。） That is, when y _i > 0, the charge is transferred from the module #j to the cell #i. In this case, the charge amount of the charge output from the module #j is y _i , On the other hand, the amount of charge received by the cell #i is η _i × y _i . On the other hand, if y _i <0, the charge is transferred from the cell #i to the module #j. In this case, the charge amount of the charge output from the cell #i is 1 / η _i × | Y _i |, on the other hand, the amount of charge received by module #j is | y _i |. Therefore, in this case, the relationship of the following formula (3) is established.

(In the above formula (3), Q _Mj ′ represents the capacity of module #j after charge transfer, and Q _i ′ represents the capacity of cell #i after charge transfer.)

（上記式（４）において、
ｉは、１〜ｎ_Ｍｊ（ただし、ｎ_Ｍｊは、ｊ番目のモジュールのセル数）の整数を表し、
ＳＯＣ_ｉは、ｊ番目のモジュールのｉ番目のセルの電荷移動を行なった後のＳＯＣを表し、
Ｑ_ｉは、ｊ番目のモジュールのｉ番目のセルの電荷移動を行なう前の容量を表し、
Ｑ_{ｍａｘ，ｉ}は、ｊ番目のモジュールのｉ番目のセルの最大容量を表し、
ｋ_ｉ・ｙ_ｉは、ｊ番目のモジュールのｉ番目のセルに出入りする電荷量を表し、
ＳＯＣ_Ｍｊは、ｊ番目のモジュールの電荷移動を行なった後のＳＯＣを表し、
η_ｉは、ｊ番目のモジュールのｉ番目のセルに電荷が入出力する場合における電荷移動効率を表す。） Therefore, in the cell #i and the module #j, the relationship between the charge amount input / output by cell balancing and the charge amount (SOC) x (x = 0 to 1) after cell balancing is expressed by the following formula (4). Can be shown.

(In the above equation (4),
i represents an integer from 1 to n _Mj (where n _Mj is the number of cells in the j-th module);
SOC _i represents the SOC after charge transfer of the i-th cell of the j-th module,
Q _i represents the capacity before charge transfer of the i-th cell of the j-th module,
Q _{max, i} represents the maximum capacity of the i th cell of the j th module,
k _i · y _i represents the amount of charge flowing into and out of the i th cell of the j th module,
SOC _Mj represents the SOC after the charge transfer of the j-th module is performed,
η _i represents the charge transfer efficiency when charge is input / output to / from the i-th cell of the j-th module. )

In the above equation (4), Q _i , Q _{i, max} , and k _i are known parameters (or parameters that can be derived from the known parameters), while x and y _i are unknown parameters. That is, there are n _Mj +1 unknown parameters (y ₁ , y ₂ ,..., Y _nMj−1 , y _nMj , x) for the number n _{Mj of} modules performing cell balancing. .

Therefore, in the present embodiment, as shown in the following formula (5), formulas corresponding to the formula (4) are established for each of the n _Mj cells that perform cell balancing and the module that performs cell balancing. When the following formula (5) is shown in a matrix, the following formula (6) is obtained. In this embodiment, it can be considered that all cells after cell balancing have the same charge amount (SOC) by performing cell balancing. Therefore, in the following equation (5), the charge amount after cell balancing The value of x (x = 0 to 1) indicating (SOC) can be made equal in all of the n _Mj cells that perform cell balancing and in a module configured by these cells.

And in this embodiment, by calculating the value of x and the value of y _i (y ₁ , y ₂ ,..., Y _nMj−1 , y _nMj ) in the matrix shown in the above equation (6), The target charge amount (value of x) at the time of cell balancing and the charge transfer amount (value of y _i ) between each cell and the module can be calculated. However, on the other hand, in the matrix shown in the above equation (6), the value of k _i changes depending on whether the value of y _i is a positive value or a negative value. The value of x and the value of y _i cannot be calculated directly from the matrix shown in 6). That is, when the value of y _i is positive, the value of k _i is η _i , and when the value of y _i is negative, the value of k _i is 1 / η _i (the above equation (4) )), The value of x and the value of y _i cannot be directly calculated from the matrix shown in the above equation (6).

Therefore, in the present embodiment, by performing the temporary calculation process described below, the value of x and the value of y _i are calculated from the matrix shown in the above equation (6), and thereby the target charging at the time of cell balancing is calculated. In addition to the quantity (value of x) and the amount of charge transfer between each cell and module (value of y _i ), the charge transfer direction (value of y _i is positive or negative, and k _i Is the value η _i or 1 / η _i ). Here, FIG. 9 is a flowchart showing temporary calculation processing at the time of cell balancing.

  The temporary calculation process described below is executed for each module M1 to M6 by the charge transfer condition setting unit 11 shown in FIG.

（上記式（７）中、ＳＯＣ_{ｃｕｒ＿ｉ}は、ｊ番目のモジュールのｉ番目のセルの現在のＳＯＣを表す。） First, in step S101, the charge transfer condition setting unit 11 acquires the current SOC of each cell calculated by the SOC calculation unit 13, and acquires the acquired current SOC of each cell and the maximum capacity (chargeable) of each cell. Based on (capacity) Q _{i, max} , the current capacity Q _i of each cell constituting each module is calculated according to the following equation (7).

(In the above formula (7), SOC _{cur_i} represents the current SOC of the i-th cell of the j-th module.)

First, in step S102, the charge transfer condition setting unit 11 uses all the k _i values (ie, k ₁ , k ₂ ,..., K _nMj−1 , k _nMj ) in the matrix shown in the above equation (6). Are set to k _i = η _i . That is, in step S102, the charge transfer direction of all the cells that form one module, so that the direction of movement from the module to the cell, temporarily sets the value of k _i to k _{i =} eta _i.

Next, in step S103, the charge transfer condition setting unit 11 constructs a matrix of Γ _C shown in the above equation (6) based on the value of k _i temporarily set in step S102 or step S106 described later.

Next, in step S104, the charge transfer condition setting unit 11 determines the value of Θ _C based on the following equation (8) derived from the above equation (6) based on the Γ _C matrix constructed in step S102. That is, the value of x and the value of y _i (y ₁ , y ₂ ,..., Y _nMj−1 , y _nMj ) are calculated, and the obtained x value and y _i value are calculated after capacity adjustment. Temporarily set as the amount of charge transfer between the SOC and each cell.

Next, in step S105, the charge transfer condition setting unit 11 sets all k values based on the value of y _i temporarily set in step S104 and the value of k _i temporarily set in step S102 or step S106 described later. _{For i} (i = 1 to n _Mj ) and corresponding y _i (i = 1 to n _Mj ), “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i It is determined whether or not the relationship of “≧ 0” is satisfied.

As a result of the determination, at least a part of all k _i and y _i corresponding thereto is “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i ≧ 0”. If the relationship is not satisfied, the process proceeds to step S106. In step S106, “k _i <1 and y _i <0” or “k _i ≧ 1” among all k _i (i = 1 to n). and a k _i which did not satisfy the relation of _{y i} ≧ 0 ", and k _i = 1 / k _i, the flow returns to step S103. That is, when k _i = η _i is set, k _i = 1 / η _i is temporarily set, and when k _i = 1 / η _i is set, k _i = η _i is set temporarily. To do. Then, again, the matrix of Γ _c is constructed based on the temporarily set k _i (step S103), and the value of Θ _c is calculated based on the above equation (8) (step S104). It is determined whether or not the relationship of k _i <1 and y _i <0 ”or“ k _i ≧ 1 and y _i ≧ 0 ”is satisfied (step S105).

（上記式（９）中、ｔ_ｉは、セルバランシングを行なうセルのうち、ｉ番目のセルの容量調整時間（単位は、秒）を表し、Ｉ_ｂａｌは、容量調整電流（単位は、Ａ）を表す。） In the present embodiment, finally, all k _i and y _i corresponding thereto are “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i ≧ 0”. until satisfying the relationship, the operations of steps S103 to S106, the value of k _i, while changing in accordance with k _i = 1 / k _i, is repeatedly executed. When all the k _i and the corresponding y _i satisfy the relationship of “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i ≧ 0”, target charge amount at the time of cell balancing (value of x), the charge amount of movement between cells (the value of y _i), and the charge or the value of the moving direction (y _i is negative or a positive, and k _i Whether the value is η _i or 1 / η _i ) is determined, and the process proceeds to step S107. Next, in step S107, the capacity adjustment time of each cell is calculated from the obtained value y _i according to the following equation (9).

(In the above formula (9), t _i represents the capacity adjustment time (unit: second) of the i-th cell among the cells that perform cell balancing, and I _bal represents the capacity adjustment current (unit: A). Represents.)

As described above, the charge transfer direction (whether the value of y _i is positive or negative) and the charge transfer of each cell when cell balancing is performed by the charge transfer condition setting unit 11 of the control device 10. The quantity y _i as well as the capacity adjustment time t _i are determined.

Next, the charge transfer condition setting unit 11 of the control device 10 is based on the charge transfer direction (whether the value of y _i is positive or negative) determined by the above method and the charge transfer amount y _i of each cell. When cell balancing is performed, a process for determining the order of cells for cell balancing is performed. Specifically, the control device 10 can determine the capacity adjustment in order from the cell having the largest absolute value of the charge transfer amount y _{i in} terms of improving the efficiency of cell balancing. In this case, when there are a plurality of modules that perform cell balancing among the modules M1 to M6, the order of the cells that perform cell balancing is determined independently for each module, and each module is independent. Cell balancing can be performed at the same time. In this embodiment, in order to further improve the efficiency of cell balancing, the order of cells to be subjected to cell balancing may be determined by the following method.

  That is, first, when the assembled battery is being discharged, the SOC is the lowest, and therefore the capacity can be adjusted from the cell that needs to be charged with the largest amount of charge. For example, as shown in FIG. 10, when the number of cells constituting the module is 6, and the charge transfer directions and charge transfer amounts of the six cells # 1 to # 6 are in the relationship shown in FIG. As shown, capacity adjustment is performed in order of cell # 5, cell # 6, cell # 4, cell # 1, and cell # 3 in order from cell # 2, which is the cell that needs to be charged with the largest amount of charge. It can be set as such a structure. In particular, when the assembled battery is being discharged, the SOC is the lowest. Therefore, by adjusting the capacity from the cell that needs to be charged with the largest amount of charge, one of the discharge currents of the modules constituting the assembled battery is reduced. The battery can be supplied with a battery that needs to be charged, so that cell balancing and discharge of the assembled battery can be performed more efficiently.

  Or, conversely, when the assembled battery is being charged, the SOC is the highest, and therefore the capacity adjustment may be performed from the cell that needs to discharge the largest amount of charge. it can. For example, as shown in FIG. 10, when the number of cells constituting the module is 6, and the charge transfer directions and charge transfer amounts of the six cells # 1 to # 6 are in the relationship shown in FIG. As shown, capacity adjustment is performed in the order of cell # 3, cell # 2, cell # 5, cell # 6, and cell # 4 in order from cell # 1, which is the cell that needs to discharge the largest amount of charge. It can be set as such a structure. In particular, when the battery pack is being charged, the SOC is the highest, so by adjusting the capacity from the cell that needs to discharge the largest amount of charge, the charging current from the cell that needs to be discharged can be reduced. Since it can be used as part of the charging current of the modules constituting the assembled battery, cell balancing and charging of the assembled battery can be performed more efficiently.

In the present embodiment, the capacity adjustment time t _i may be used instead of the charge transfer amount y _i when determining the order of cells for cell balancing.

Next, the charge transfer condition setting unit 11 of the control device 10 first determines a cell to be subjected to cell balancing based on the information on the order of cells to be subjected to cell balancing set according to the above method, and performs cell balancing on the determined cell. Is set as a capacity adjustment target cell. Then, the charge transfer condition setting unit 11 calculates the charge transfer direction (whether the value of y _i is positive or negative) calculated according to the above method and the charge transfer amount y _i (or capacity adjustment) of each cell. together with the information of the time t _i), and it transmits the information of the capacity adjustment target cell for cell balancing, as a cell balancing condition, the current prediction control unit 12.

<(B) Method of performing only module balancing>
Next, a specific capacity adjustment condition setting method in the method of (B) performing only module balancing will be described. As described above, module balancing according to the present embodiment is a method in which charge transfer is performed between modules to be subjected to module balancing, thereby adjusting capacity between modules.

Here, FIG. 13 is a schematic diagram showing module balancing according to the present embodiment. The example shown in FIG. 13 has a configuration having three modules # (j−1), module #j, and module # (j + 1) adjacent to each other. As shown in FIG. The current capacities of the modules are Q _Mj−1 , Q _Mj , and Q _{Mj + 1} , respectively, and the amount of charge to be moved between the module # (j−1) and the module #j is z _j−1 and the module #j. Let z _j be the amount of charge transferred to and from module # (j + 1). In the following, first, the configuration shown in FIG. 13 will be described as an example.

First, in FIG. 13, considering the charge amount z _j−1 to be moved between the module # (j−1) and the module #j, when z _j−1 is positive, the module # (j− The charge moves from 1) to module #j. That is, in this case, it is defined that the charge of the charge amount z _j−1 is output from the module # (j−1), and the module #j receives the charge of the charge amount η _Mj−1 × z _j−1. be able to. Here, η _Mj−1 is the charge transfer efficiency when transferring charges between the module # (j−1) and the module #j.

On the other hand, when z _j−1 is negative, the charge moves from the module #j to the module # (j−1). In this case, the charge amount 1 / η _Mj−1 × from the module #j | Z _j−1 | is output, and module # (j−1) can be defined as receiving a charge of | z _j−1 |.

Similarly, considering the amount of charge z _j to be moved between module #j and module # (j + 1), if z _j is positive, the charge moves from module #j to module # (j + 1). It becomes. That is, in this case, it can be defined that the charge of the charge amount z _j is output from the module #j, and the module # (j + 1) receives the charge of the charge amount η _Mj × z _j . Here, η _Mj is the charge transfer efficiency when transferring charge between the module #j and the module # (j + 1).

On the other hand, when z _j is negative, the charge moves from module # (j + 1) to module #j. In this case, the charge amount 1 / η _Mj × | z _j | from module # (j + 1). Can be defined as module #j receiving a charge of | z _j |.

（上記式（１０）において、
ｊは、１〜ｍまでの整数を表し、
ｘは、電荷移動を行なった後の各モジュールのＳＯＣを表し、
Ｑ_Ｍｊは、ｊ番目のモジュールの電荷移動を行なう前の容量を表し、
Ｑ_{Ｍｊ，ｍａｘ}は、ｊ番目のモジュールの最大容量を表し、
ｚ_ｊ−１は、ｊ−１番目のモジュールから、ｊ番目のモジュールに対して移動させる電荷量を表し、
ｐ_ｊ−１・ｚ_ｊ−１は、ｊ−１番目のモジュールから、ｊ番目のモジュールに移動する電荷量を表し、
ｚ_ｊは、ｊ番目のモジュールから、ｊ＋１番目のモジュールに対して移動させる電荷量を表し、
η_Ｍｊは、ｊ番目のモジュールから、ｊ＋１番目のモジュールに対して電荷を移動させる際の電荷移動効率を表す。） Therefore, for example, the relationship between the charge amount input / output to / from module #j by module balancing and the charge amount (SOC) x (x = 0 to 1) of module #j after cell balancing is expressed by the following equation (10). Can show.

(In the above equation (10),
j represents an integer from 1 to m;
x represents the SOC of each module after charge transfer,
Q _Mj represents the capacitance before charge transfer of the j-th module,
Q _{Mj, max} represents the maximum capacity of the jth module;
z _j-1 represents the amount of charge to be moved from the j-1 module to the j module,
p _j−1 · z _j−1 represents the amount of charge moving from the j−1th module to the jth module,
z _j represents the amount of charge to be moved from the j-th module to the j + 1-th module,
η _Mj represents the charge transfer efficiency when the charge is transferred from the j-th module to the j + 1-th module. )

また、本実施形態において、現在の容量Ｑ_Ｍｊと、最大容量Ｑ_{Ｍｊ，ｍａｘ}、およびＳＯＣ_Ｍｊは、それぞれ、モジュールバランシングを行うモジュールの数をｍとした場合に、モジュールバランシングを行うモジュールのうち、ｊ（ｊ＝１〜ｍ）番目のモジュールの現在の容量、最大容量、およびＳＯＣを意味する。また、上記式（１１）〜(１２)中、ｎ（ｊ）は、モジュールバランシングを行なうモジュールのうち、ｊ番目のモジュールを構成するセルの数を意味する。 The current capacity Q _Mj of the module is _calculated according to the following formula (11), and the maximum capacity (chargeable capacity) Q _{Mj, max} of the module is further _calculated according to the following formula (12). Can be calculated based on the current capacity Q _i of each cell constituting each module and the maximum capacity Q _{i, max} of each cell according to the following equation (13).

In the present embodiment, the current capacity Q _Mj , the maximum capacity Q _{Mj, max} , and the SOC _Mj are modules out of modules that perform module balancing, where m is the number of modules that perform module balancing. It means the current capacity, maximum capacity, and SOC of the jth module (j = 1 to m). In the above formulas (11) to (12), n (j) means the number of cells constituting the j-th module among the modules that perform module balancing.

Also in the above equation (10), as in the above equation (4), Q _Mj , Q _{Mj, max} , and p _j−1 are known parameters (or parameters that can be derived from the known parameters), while , X, z _j−1 , z _j are unknown parameters. That is, if m is the number of modules to be subjected to module balancing, m unknown parameters (z ₁ , z ₂ ,..., Z _m−1 , x) exist.

Therefore, as in the case of cell balancing, the above equation (10) is expressed in a matrix form for each of the m modules to be subjected to module balancing, and the following equation (14) is obtained. In module balancing, as in the cell balancing described above, all modules after module balancing can be considered to have the same amount of charge (SOC). Therefore, in equation (10) above, the amount of charge after module balancing The value of x (x = 0 to 1) indicating (SOC) can be made equal in all m cells that perform module balancing.

Also in module balancing, similarly to the cell balancing described above, the temporary calculation process described below is performed to calculate the value of x and the value of z _j from the matrix shown in the equation (14). Therefore, in addition to the target charge amount (value of x) at the time of module balancing and the charge transfer amount between modules (value of z _j ), whether the charge transfer direction (value of z _j is positive or negative) , And the value of p _j is η _Mj or 1 / η _Mj ). Here, FIG. 14 is a flowchart showing temporary calculation processing at the time of module balancing.

  The temporary calculation process described below is executed by the charge transfer condition setting unit 11 shown in FIG. 5 in the same manner as the cell balancing described above.

First, in step S201, the charge transfer condition setting unit 11 acquires the current SOC of each cell calculated by the SOC calculation unit 13, and acquires the acquired current SOC of each cell and the maximum capacity (chargeable) of each cell. Based on the capacity Q _{i, max} , the current capacity Q _Mj of each module is calculated according to the above formulas (7), (11), (12), and (13).

Next, in step S202, the charge transfer condition setting unit 11 determines all the values of p _j (that is, p ₁ , p ₂ ,...) In the matrix shown in the equation (14), as in the cell balancing described above. , P _m−1 ) are temporarily set to p _j = η _Mj . In step S203, the charge transfer condition setting unit 11 constructs a matrix of Γ _{M in} the matrix shown in the above formula (14) based on the value of p _j provisionally set in step S202 or step S206 described later. To do.

Next, in step S204, the charge transfer condition setting unit 11 sets the value of Θ _M based on the following equation (15) derived from the above equation (14) based on the Γ _M matrix constructed in step S203. The values of x and p _j · z _j obtained by the calculation are temporarily set as the amount of charge transfer between the SOC and each module after capacity adjustment.

Next, in step S205, the charge transfer condition setting unit 11 sets all the p _j values based on the value of p _j temporarily set in step S204, and further, the value of p _j temporarily set in step S202 or step S206 described later. _j (j = 1 to m) and z _j (j = 1 to _m ) corresponding thereto, “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j ≧ 0” It is determined whether or not the relationship “is satisfied.

As a result of the determination, at least a part of all p _j and z _j corresponding thereto is “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j ≧ 0”. If the relationship is not satisfied, the process proceeds to step S206. In step S206, “p _j <1 and z _j <0” or “p _j ≧ 1” among all p _j (j = 1 to _m ). and a _{p j} which did not satisfy the relationship _{z j} ≧ 0 _", if set to p j = 1 / _{p j,} the flow returns to step S203. Then, again, a Γ _M matrix is constructed based on the temporarily set p _j (step S203), and the value of Θ _M is calculated based on the above equation (15) (step S204). In such a process, all p _j and the corresponding z _j satisfy the relationship of “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j ≧ 0”. Until (step S205 = Yes), the process is repeatedly executed.

（上記式（１６）中、ｔ_Ｍｊは、モジュールバランシングを行なうセルのうち、ｊ番目のモジュールの容量調整時間（単位は、秒）、Ｉ_ｂａｌは、容量調整電流（単位は、Ａ）） When all p _j and the corresponding z _j satisfy the relationship of “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j ≧ 0”, Target charge amount (value of x) at the time of module balancing, charge transfer amount between each module (value of z _j ), and charge transfer direction (whether the value of z _j is positive or negative, and p _j Whether the value is η _Mj or 1 / η _Mj ), the process proceeds to step S207, and the charge transfer condition setting unit 11 follows the following equation (16) from the obtained z _j value. The capacity adjustment time for each module is calculated.

(In the above equation (16), t _Mj is the capacity adjustment time (unit: second) of the j-th module among cells performing module balancing, and I _bal is the capacity adjustment current (unit: A))

As described above, the charge transfer direction (whether the value of z _j is positive or negative) and the charge transfer of each cell when module balancing is performed by the charge transfer condition setting unit 11 of the control device 10. A quantity z _j as well as a capacity adjustment time t _j are determined.

Next, the charge transfer condition setting unit 11 of the control device 10 has information on the charge transfer direction determined by the above method (whether the value of z _j is positive or negative) and the charge transfer amount z _j between the modules. Is transmitted to the current prediction control unit 12 as a module balancing condition. In the present embodiment, module balancing can be performed simultaneously by driving the module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25 shown in FIG. 1 at the same time. Therefore, unlike the above-described cell balancing, the operation for determining the order in which module balancing is performed is not particularly required.

Here, as shown in FIG. 1, the modules M1 to M6 constituting the assembled battery system of this embodiment are subjected to module balancing by module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25. Therefore, module balancing of the modules M1 to M6 can be represented by the schematic diagram shown in FIG. As shown in FIG. 15, among the modules M1 to M6 constituting the assembled battery, the current capacity of the module M1 is Q _M1 and the maximum capacity Q _{M1 and max} . The current capacities are Q _M2 , Q _M3 , Q _M4 , Q _M5 , and Q _M6 , respectively, and the maximum capacities are Q _{M2, max} , Q _{M3, max} , Q _{M4, max} , Q _{M5, max} , Q, respectively. _{Let M6, max} . Further, as shown in FIG. 15, _{z 1} the amount of charge moves from the module M1 to the module M2, a charge amount _{z 2} to move from the module M2 to the module M3, _{z 3} the amount of charge transferred from module M4 to the module M5 The amount of charge moving from the module M5 to the module M6 is z ₄ , and the amount of charge moving from the module M2 to the module M5 is z ₅ .

As shown in FIG. 1, a specific example of the case where each of the modules M1 to M6 performs module balancing by using the module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25. The relationship between the amount of charge input / output to / from M6 and the amount of charge (SOC _{M1 to} SOC _M6 ) x (x = 0 to 1) of each module M1 to M6 after module balancing is expressed by the following equation (17) It becomes. Further, when this is shown as a matrix, the following formula (18) is obtained.

Even in this case, the temporary calculation process is performed in the same manner as described above in the same manner as in the method using the above expression (15), so that the value of x and the value of z _j can be calculated from the above expression (15). In addition to the target charge amount (value of x) at the time of module balancing and the charge transfer amount between the modules (value of z _j ), the charge transfer direction (value of z _j is positive) Or whether the value of p _j is η _Mj or 1 / η _Mj ). Based on the obtained result, the charge transfer amount z _j and the capacity adjustment time t _{Mj of} each module are determined according to the above equation (16).

<(C) Method of performing cell balancing and module balancing simultaneously>
Next, a specific capacity adjustment condition setting method in (C) the method of performing cell balancing and module balancing simultaneously will be described. As described above, the method for performing cell balancing and module balancing at the same time according to the present embodiment performs charge transfer between the cells constituting the module and the modules as described above. The cell balancing is performed to adjust the capacity of each of the cells constituting the cell, and at the same time, the charge is transferred between the modules to be module balanced, thereby adjusting the capacity between the modules. . In the following, the method of performing cell balancing and module balancing at the same time is referred to as cell-module balancing.

（上記式（１９）において、
ｉは、１〜ｎ（ただし、ｎは、組電池を構成するセルの総数）の整数を表し、
ＳＯＣ_ｉは、ｉ番目のセルの電荷移動を行なった後のＳＯＣを表し、
Ｑ_ｉは、ｉ番目のセルの電荷移動を行なう前の容量を表し、
Ｑ_{ｍａｘ，ｉ}は、ｉ番目のセルの最大容量を表し、
ｋ_ｉ・ｙ_ｉは、ｉ番目のセルが属するｊ番目のモジュールとの電荷移動により、ｉ番目のセルに出入りする電荷量を表し、
ｐ_ｊ−１・ｚ_ｊ−１は、ｉ番目のセルが属するｊ−１番目のモジュールから、ｊ番目のモジュールに移動する電荷量を表し、
ｚ_ｊは、ｉ番目のセルが属するｊ番目のモジュールから、ｊ＋１番目のモジュールに対して移動させる電荷量を表し、
ＳＯＣ_Ｍｊは、ｊ番目のモジュールの電荷移動を行なった後のＳＯＣを表し、
Ｑ_Ｍｊは、ｊ番目のモジュールの電荷移動を行なう前の容量を表し、
Ｑ_{Ｍｊ，ｍａｘ}は、ｊ番目のモジュールの最大容量を表し、
ｎ_Ｍｊは、ｊ番目のモジュールを構成するセルの数を表し、
ｍは、組電池を構成するモジュールの総数を表し、
η_ｉは、ｉ番目のセルに電荷が入出力する場合における電荷移動効率を表し、
η_Ｍｊは、ｊ番目のモジュールに電荷が入出力する場合における電荷移動効率を表す。） Also in the cell-module balancing, as in the case of performing only the cell balancing and the case of performing only the module balancing described above, the charge amount input / output by the cell balancing in each cell #i and the module #j, and after the cell balancing Charge amount (SOC) x (x = 0 to 1), and the amount of charge input / output by module balancing and the amount of charge after cell balancing (SOC) x in module #j and the entire assembled battery The relationship with (x = 0 to 1) can be shown by the following formula (19).

(In the above equation (19),
i represents an integer of 1 to n (where n is the total number of cells constituting the assembled battery);
SOC _i represents the SOC after charge transfer of the i-th cell,
Q _i represents the capacitance before charge transfer of the i-th cell,
Q _{max, i} represents the maximum capacity of the i th cell,
k _i · y _i represents the amount of charge that enters and exits the i th cell due to charge transfer with the j th module to which the i th cell belongs,
p _j−1 · z _j−1 represents the amount of charge moving from the j−1th module to which the ith cell belongs to the jth module,
z _j represents the amount of charge to be moved from the j-th module to which the i-th cell belongs to the j + 1-th module,
SOC _Mj represents the SOC after the charge transfer of the j-th module is performed,
Q _Mj represents the capacitance before charge transfer of the j-th module,
Q _{Mj, max} represents the maximum capacity of the jth module;
n _Mj represents the number of cells constituting the jth module,
m represents the total number of modules constituting the assembled battery,
η _i represents the charge transfer efficiency when charge is input to and output from the i-th cell,
η _Mj represents the charge transfer efficiency when charge is input to and output from the jth module. )

Also in the above equation (19), Q _i , Q _{i, max} , k _i , and p _j can be derived from known parameters (or known parameters, as in the above equations (4) and (13)). On the other hand, x, y _i , and z _j are unknown parameters. That is, when n is the number of cells for module balancing and m is the number of modules, n + m unknown parameters (y ₁ , y ₂ ,..., Y _n−1 , y _n , z ₁ , Z ₂ ,..., Z _m−2 , z _m−1 , x).

Therefore, as in the case of performing only cell balancing and performing only module balancing, the above equation (19) is matrixed for each of n cells for cell balancing and m modules for module balancing. Since the equation obtained by doing this is the following equation (20), and since all the cells and modules after cell-module balancing can be considered to have the same amount of charge (SOC), the same as above By performing temporary calculation processing as described above, the value of x, the value of y _i , and the value of z _j can be calculated from the following equation (20). Thus, the target charge amount at the time of cell-module balancing (value of x), the amount of charge transfer between cells and modules in cell balancing (value of y _i ), the amount of charge transfer between modules in module balancing (z _j )), the charge transfer direction (y _i , z _j is positive or negative, whether k _i is η _i or 1 / η _i , whether the value of p _j is η _Mj or 1 / η _Mj ).

  Here, FIG. 19 is a flowchart showing temporary calculation processing at the time of cell-module balancing. In the flowchart shown in FIG. 19, the process in the case of performing cell-module balancing for all the modules constituting the assembled battery is shown.

  The temporary calculation process described below is executed by the charge transfer condition setting unit 11 shown in FIG.

First, in step S301, the charge transfer condition setting unit 11 acquires the current SOC of each cell calculated by the SOC calculation unit 13, and acquires the acquired current SOC of each cell and the maximum capacity (chargeable) of each cell. Based on the capacity) Q _{i, max} , the current capacity Q _i of each cell constituting each module is calculated according to the above equation (7), and the above equations (7), (11), (12), ( 13) Calculate the current capacity Q _Mj of each module.

Next, in step S302, the charge transfer condition setting unit 11 performs all the k _i values (that is, k ₁ , k) in the matrix in the same manner as in the case where only the cell balancing described above is performed. _2, ..., all values) together with tentatively set to _{k i} = _{η i} of _{k n,} the value of all the _{p j (i.e.,} p _1, p 2, ..., all values of _{p m} ) _Is temporarily set to p _j = η _Mj . In step S303, the charge transfer condition setting unit 11 constructs a matrix of Γ _CM based on the values of k _i and p _j temporarily set in step S302 or steps S306 and S307 described later.

Next, in step S304, charge transfer condition setting unit 11, based on a matrix of gamma _CM constructed in step S303, on the basis of the following equation (21) derived from the above equation (20), the value of theta _CM The values of x and k _i and p _j obtained by calculation are temporarily set as the SOC after capacity adjustment, and the amount of charge transfer between each cell and module, and between each module.

Next, in step S305, the charge transfer condition setting unit 11 sets “k _i <1 and y for all k _i (i = 1 to n) and corresponding y _i (i = 1 to n). _i <0 "or" _{k i} ≧ 1 and, _{y i} ≧ 0 is satisfied a relationship ", and all _p j (j = 1~m) and _z j corresponding thereto (j = 1 ˜m), it is determined whether or not the relationship “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j ≧ 0” is satisfied.

As a result of the determination, at least a part of all k _i and y _i corresponding thereto is “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i ≧ 0”. If the relationship is not satisfied, and at least a part of all p _j and the corresponding z _j is “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j If the relationship “≧ 0” is not satisfied, the process proceeds to step S306. In step S306, among all k _i (i = 1 to n), the relationship of “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i ≧ 0” is established. K _i that is not satisfied is temporarily set to k _i = 1 / k _i , and then the process proceeds to step S307. In step S307, among all p _j (j = 1 to _m ), “p _j <1 P _j that does not satisfy the relationship of z _j <0 ”or“ p _j ≧ 1 and z _j ≧ 0 ”is temporarily set to p _j = 1 / p _j and the process returns to step S303.

Then again, if based on the set _k i, _{p j,} executes the construction of the matrix of gamma _CM (step S303), based on the equation (21), performs calculation of the values of theta _CM (step S304 ), Such a process is performed so that all k _i and y _i corresponding thereto have a relationship of “k _i <1, and y _i <0” or “k _i ≧ 1 and y _i ≧ 0”. And all p _j and the corresponding z _j satisfy the relationship of “p _j <1, and z _j <0” or “p _j ≧ 1 and z _j ≧ 0” (step The process is repeated until S305 = Yes.

And all k _i and y _i corresponding thereto satisfy the relationship of “k _i <1 and y _i <0” or “k _i ≧ 1 and y _i ≧ 0”, and all P _j and the corresponding z _j satisfy the relationship of “p _j <1 and z _j <0” or “p _j ≧ 1 and z _j ≧ 0”. Target charge amount (value of x) at the time of balancing, charge transfer amount between each cell and module (value of y _i ), charge transfer amount between each module (value of z _j ), and charge transfer direction (y whether the values of _i and z _j are positive or negative, the value of k _i is η _i or 1 / η _i , and the value of p _j is η _Mj or 1 / η determines that can determine _Mj is either), the process proceeds to step S308, the obtained value of _{y i,} from the value of _{z j,} the equation (9 According to the above formula (16), to calculate the capacity adjustment time of each cell and each module.

As described above, the charge transfer direction (whether the values of y _i and z _j are positive or negative) when performing cell-module balancing by the charge transfer condition setting unit 11 of the control device 10, The amount of charge transfer between the cell and the module (value of y _i ), the amount of charge transfer between each module (value of z _j ), and the capacity adjustment times t _i and t _Mj are determined.

Next, the charge transfer condition setting unit 11 of the control device 10 determines the charge transfer direction (whether the value of y _i is positive or negative) determined by the above method, and the charge transfer amount y between each cell and the module. Based on _i , a process for determining the order of cells for cell balancing when cell-module balancing is performed is performed. Note that the order of modules that perform cell balancing can be determined by, for example, a method similar to the above-described method (A) of performing only cell balancing. In this case, if there are multiple modules that perform cell balancing, the order of cells to be cell-balanced is determined independently for each module, and cell balancing is performed independently for each module simultaneously. Can do.

Next, the charge transfer condition setting unit 11 of the control device 10 first determines a cell to be subjected to cell balancing based on the information on the order of cells to be subjected to cell balancing set according to the above method, and performs cell balancing on the determined cell. Set as the cell to perform. Then, the charge transfer condition setting unit 11 calculates the charge transfer direction (y _i , whether the value of z _j is positive or negative) calculated according to the above method, and the charge transfer amount y _{i of} each cell (or , Capacity adjustment time t _i ) and the amount of charge transfer between each module (value of z _j ), and information on capacity adjustment times t _i and t _Mj , and information on the capacity adjustment target cell for cell balancing, It transmits to the electric current prediction control part 12 as balancing conditions.

  As described above, in the present embodiment, the charge transfer condition setting unit 11 of the control device 10 (A) performs only cell balancing, (B) performs only module balancing, and (C) cell balancing. In each of the methods for performing module balancing at the same time, capacity adjustment conditions are set.

<Charge transfer process and current value limiting process>
Next, processing executed by the current prediction control unit 12 of the control device 10 shown in FIG. 5 will be described. In the following, a case where cell-module balancing is performed by a method of performing (C) cell balancing and module balancing simultaneously will be described as an example.

That is, first, the current prediction control unit 12 of the control device 10 determines the charge transfer direction (whether the values of y _i and z _j are positive or negative) set by the charge transfer condition setting unit 11 and each cell. Charge transfer amount y _i (or capacity adjustment time t _i ), charge transfer amount between each module (value of z _j ), information on capacity adjustment time t _i , t _Mj , and capacity adjustment target for cell balancing Get cell information. That is, cell-module balancing conditions are acquired. Then, based on these pieces of information, the current prediction control unit 12 uses the cell balancing circuits ACB1 to ACB6 (hereinafter, abbreviated as “cell balancing circuit ACB” as appropriate) shown in FIG. 1, module balancing circuits MMB12, MMB23, A current value flowing through each wiring constituting the MMB 45, MMB 56, and MMB 25 (hereinafter abbreviated as “module balancing circuit MMB” as appropriate) is predicted. That is, the current prediction control unit 12 performs cell balancing for the capacity adjustment target cell for cell balancing, and configures the cell balancing circuit ACB and the module balancing circuit MMB when module balancing is performed between the modules M1 to M6. The current value flowing in each wiring to be predicted is predicted.

Then, as a result of predicting the current value flowing in each wiring configuring the cell balancing circuit ACB and the module balancing circuit MMB, if any wiring is less than the predetermined threshold value I _LIM , the charge transfer condition setting unit 11 Based on the set charge transfer condition, the cell balancing circuit ACB and the module balancing circuit MMB are controlled to execute cell-module balancing. Alternatively, when there is a wiring whose predicted current value is equal to or greater than the predetermined threshold value I _LIM , processing for limiting the current value is executed. In the present embodiment, the threshold value I _LIM can be set based on the current value that can flow through each wiring.

For example, in the cell balancing circuit ACB and the module balancing circuit MMB shown in FIG. 2, a situation as shown in FIG. 17 can be considered depending on how the state of charge of each cell and each module varies. That is, FIG. 17 shows the following scene, and the following current flows through the point P in FIG.
Currents I1 and I2 that flow due to cell balancing between the cell C32 and the module M2
Currents I3 and I4 flowing by performing cell balancing between the cell C33 and the module M3
A current I5 that flows by performing module balancing between the module M1 and the module M2
Currents I6 and I7 that flow due to module balancing between modules M2 and M3
A current I8 flowing by performing module balancing between the module M2 and the module M5

  That is, in the scene example shown in FIG. 17, by performing cell-module balancing, currents I1, I3, I5, I6, I7, and I8 that flow in the same direction at the point P are concentrated. In such a case, the current value that can be passed at the point P and its vicinity is exceeded, and the wiring may be damaged.

For example, in the scene example shown in FIG. 17, the voltage of each cell is 3.6 V, the voltage of the module is 57.6 V (= 3.6 V × 16), the current value of cell balancing is 5 A, and the charge transfer efficiency of cell balancing is When the module balancing current value is 2A and the module balancing charge transfer efficiency is 85%, the current values of the currents I1 to I8 are as follows. In the following, the direction from the right side of the drawing (the transformer T25 side) toward the point P is positive.
・ I1 = 5A
・ I2 = −0.234A (= −5A × 0.75 × (3.6V / 57.6V))
・ I3 = 5A
・ I4 = −0.417A (= −5A × (1 / 0.75) × (3.6V / 57.6V))
・ I5 = 2A
・ I6 = 2A
・ I7 = 1.7A (= 2A × 0.85)
・ I8 = 2A
That is, 9.349A (= I1 + I2 + I3 + I4) flows due to cell balancing and 7.7A (= I5 + I6 + I7 + I8) flows due to cell balancing, and a total current of 17.05A is concentrated at point P.

Therefore, in this embodiment, in order to prevent the current from concentrating on the specific wiring in this way, the current value is more than a predetermined threshold value I _LIM by the current prediction control unit 12 of the control device 10. In the case where there is a wiring to be processed, a process for limiting the current value is executed so that the current value flowing through the wiring is less than a predetermined threshold value I _LIM .

In this embodiment, there are various methods for limiting the current value. For example, there is a method for reducing the current command value when performing cell balancing and module balancing. Specifically, the current value flowing through the wiring can be reduced by controlling the on / off duty ratio of the current when performing cell balancing and module balancing and shortening the on-time ratio. Alternatively, it is also possible to reduce the value of the current flowing through the wiring by changing the timing of turning on the current by, for example, cell balancing and module balancing without changing the on / off duty ratio. In particular, according to the method of reducing the current command value, it is possible to effectively prevent damage to wiring due to current concentration while simultaneously performing cell balancing and module balancing. In this case, a mode in which the current command value is reduced only for the cell or module in which cell balancing or module balancing is performed by using a wiring whose current value is equal to or greater than a predetermined threshold value I _LIM may be adopted.

  Alternatively, as another method for limiting the current value, a method in which one of cell balancing and module balancing is not performed may be employed. For example, in the above example, by stopping the cell balancing, the current flowing through the point P can be reduced from 17.05 A to 7.7 A. Alternatively, by stopping the module balancing, the current flowing through the point P can be reduced from 17.05A to 9.349A. In this case, either cell balancing or module balancing may be stopped, but a method of stopping module balancing and performing only cell balancing is more preferable. By executing cell balancing in preference to module balancing, for example, in the example shown in FIG. 17, cell balancing of C32 and C33 is completed early, and after these cell balancing is completed, Cell balancing can be performed, which makes it possible to complete capacity adjustment of the entire assembled battery at an early stage while effectively preventing damage to wiring due to current concentration.

In this case, a mode may be adopted in which cell balancing and module balancing are canceled for some of the cells and modules that are performing cell balancing and module balancing. For example, in the above example, when the threshold value I _LIM is 15 A, the current flowing to the point P is reduced by 3.7 A (= I6 + I7) by stopping the module balancing between the module M2 and the module M3. The current concentrated at the point P can be 13.35A.

  Alternatively, as another method of limiting the current value, cell balancing and module balancing are given priority to cells and / or modules having large variations, and cell balancing and module balancing are stopped for other cells and / or modules. It is good also as such an aspect. Since cells and modules with large variations take longer to adjust the capacity, cell balancing and module balancing are given priority for such cells and modules, effectively preventing damage to wiring due to current concentration. It becomes possible to complete the capacity adjustment of the entire assembled battery at an early stage.

Then, the current prediction control unit 12 of the control device 10 uses the cell-module whose current value is limited by any one of the above methods when there is a wiring whose predicted current value is equal to or greater than the predetermined threshold value I _LIM. The cell-module balancing is executed by controlling the cell balancing circuit ACB and the module balancing circuit MMB under the cell-module balancing condition in which the balancing condition is set and the current value is limited.

In addition, the current prediction control unit 12 determines that the cell-module balancing condition set by the charge transfer condition setting unit 11 is the SOC calculation unit 13 as it is when any wiring is less than the predetermined threshold value I _LIM. On the other hand, if there is a wiring whose predicted current value is equal to or greater than the predetermined threshold value I _LIM , the cell-module balancing condition in which the current value is limited is transmitted to the SOC calculation unit 13. When executing the process of limiting the current value, the SOC calculation unit 13 calculates the SOC of each cell by transmitting the cell-module balancing condition with the current value limited to the SOC calculation unit 13 as described above. Therefore, the accuracy of the cell-module balancing condition can be improved by the charge transfer condition setting unit 11 for setting the cell-module balancing condition using the SOC calculation result by the SOC calculation unit 13. Is possible.

  In the present embodiment, the process of predicting the current value flowing through each wiring configuring the cell balancing circuit ACB and the module balancing circuit MMB performed by the current prediction control unit 12 may be performed for all the wirings. It is good also as an aspect which estimates the electric current value which flows only about the wiring (wiring containing the point P and the point Q in the example shown in FIG. 17) shared between several modules. In particular, in the present embodiment, current concentration occurs in wiring shared by a plurality of modules. Therefore, only the wiring in which current concentration may occur in this way is predicted for the current value. The calculation load can be reduced by using the above-described object. In addition, when only a wiring that may cause current concentration is targeted for current value prediction, it further flows to a predetermined point where current concentration occurs such as point P and point Q shown in FIG. It is good also as a structure which makes only an electric current value the object of prediction.

  Further, in the above description, the charge transfer process and the current value limiting process when performing cell-module balancing have been described. However, the same applies when performing only cell balancing, and also when performing only module balancing. Of course it is possible.

  According to this embodiment, when performing capacity adjustment by active balancing, a target charge amount, a charge amount to be moved between each cell and module and / or between modules, a charge movement direction, and a capacity adjustment time Therefore, capacity adjustment by active balancing can be performed in a short time and with high efficiency. In particular, according to the present embodiment, capacity adjustment can be performed based on the target charge amount and the amount of charge moved between each cell and module and / or between each module. At the end, it is possible to effectively prevent the occurrence of chattering that repeats charging and discharging.

In addition, according to the present embodiment, when capacity adjustment is performed by active balancing, the current value flowing in the wiring configuring the cell balancing circuit ACB and the module balancing circuit MMB is predicted, and the predicted current value is a predetermined threshold value. When there is a wiring that is equal to or greater than I _LIM, a process for limiting the current value is executed. Therefore, it is possible to effectively prevent the wiring from being damaged due to current concentration when performing capacity adjustment by active balancing. In particular, when the cell balancing circuit ACB and the module balancing circuit MMB are configured as in the present embodiment and the cell balancing and the module balancing are performed at the same time, as shown in the above-described example shown in FIG. However, according to the present embodiment, when there is a wiring whose predicted current value is equal to or greater than a predetermined threshold value I _LIM, a process for limiting the current value is performed. Thus, such current concentration can be effectively prevented.

  Further, in the present embodiment, as shown in FIG. 17, even when the configuration is such that a plurality of modules share wiring, and the circuit configuration constituting the assembled battery is simplified, such a plurality of modules are shared. Current concentration in the wiring to be performed can be prevented. Therefore, according to the present embodiment, the manufacturing cost can be appropriately reduced.

  In the above-described embodiment, the cell balancing circuits ACB1 to ACB6 and the module balancing circuits MMB12, MMB23, MMB45, MMB56, and MMB25 are the charge transfer circuit of the present invention, and the SOC calculation unit 13 of the control device 10 is the detection means of the present invention. In addition, the charge transfer condition setting unit 11 of the control device 10 corresponds to the charge transfer amount calculation unit of the present invention, and the current prediction control unit 12 of the control device 10 corresponds to the control unit of the present invention.

  As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Control apparatus C1-C96 ... Cell M1-M6 ... Module ACB1-ACB6 ... Cell balancing circuit MMB12, MMB23, MMB45, MMB56, MMB25 ... Module balancing circuit

Claims (10)

A battery pack control device comprising a plurality of cells connected in series,
Cell balancing for transferring charge between a specific cell and a module composed of a plurality of cells including the specific cell, and / or module balancing for transferring charge between modules composed of a plurality of cells Multiple charge transfer circuits possible;
Detecting means for detecting a current state of charge of each cell and / or each module constituting the assembled battery;
Charge transfer amount calculation that calculates the charge transfer amount and charge input / output direction for each cell and / or module that performs charge transfer, taking into account the current charge state and charge transfer loss when charge is input / output Means,
Based on the calculated charge transfer amount and charge input / output direction, a cell and / or module that performs charge transfer is set, and the plurality of charge transfer circuits are controlled. Control means for performing a charge transfer process for performing the cell balancing and / or the module balancing,
Among the plurality of charge transfer circuits, at least some of the charge transfer circuits have wiring shared with other charge transfer circuits,
The control means predicts a current value that flows through the plurality of charge transfer circuits when the charge transfer process is executed before executing the charge transfer process, and the predicted current value is equal to or greater than a predetermined threshold value. In this case, the battery pack control apparatus is characterized in that a current value flowing through the plurality of charge transfer circuits is limited to be less than the threshold value. The battery pack control device according to claim 1,
The control unit controls the assembled battery, wherein the cell balancing and the module balancing are performed simultaneously. The battery pack control device according to claim 1 or 2,
When the control means predicts the current value flowing through the plurality of charge transfer circuits, the control unit predicts a current value flowing through a wiring shared among the plurality of modules among the wirings constituting the plurality of charge transfer circuits. And when the value of the current flowing through the wiring is equal to or greater than the threshold value, the control device for the assembled battery is limited so that the value of the current flowing through the wiring is less than the threshold value. The battery pack control device according to any one of claims 1 to 3,
The detection means determines the current charge state of each cell and / or each module based on the voltage of the cells and / or modules constituting the assembled battery and the charge transfer processing conditions set by the control means. Detect
When the control means performs a process of limiting the value of the current flowing through the plurality of charge transfer circuits to be less than the threshold value, the detection means is less than the threshold value as a condition for the charge transfer process. A battery pack control device using a current value limited to the above. The battery pack control device according to any one of claims 1 to 4,
When the predicted current value is equal to or greater than a predetermined threshold as a result of predicting the current value flowing through the plurality of charge transfer circuits, the control unit determines that the current value flowing through the plurality of charge transfer circuits is less than the threshold value. The battery pack control apparatus is characterized by reducing a current command value when executing the charge transfer process. The battery pack control device according to claim 5,
The control means performs charge transfer processing only for cells and / or modules in which charge transfer is performed using a wiring in which the predicted current value is equal to or greater than a predetermined threshold among cells and / or modules that perform charge transfer. The battery pack control apparatus is characterized in that the current command value when executing is reduced. The battery pack control device according to any one of claims 1 to 4,
When the predicted current value is equal to or greater than a predetermined threshold as a result of predicting the current value flowing through the plurality of charge transfer circuits, the control unit determines that the current value flowing through the plurality of charge transfer circuits is less than the threshold value. An assembled battery control device characterized in that the cell and / or module for charge transfer is set again so that The battery pack control device according to claim 7,
The control unit for an assembled battery, wherein the control unit resets a cell and / or a module that performs charge transfer so that only one of the cell balancing and the module balancing is executed. The battery pack control device according to claim 8,
The assembled battery control device, wherein the control means resets a cell and / or a module that performs charge transfer so that only the cell balancing is performed. The battery pack control device according to claim 7,
The control unit is configured to control a cell and / or module for performing charge transfer again so that charge transfer is preferentially performed for cells and / or modules having large variations. .

Images