JP4569460B2 - Battery pack capacity adjustment device - Google Patents

Description

  The present invention relates to an apparatus for adjusting capacity between a plurality of cells constituting an assembled battery.

  Conventionally, capacity adjustment amount is calculated for each cell by calculating the capacity adjustment amount for each cell, obtaining the discharge time based on the calculated capacity adjustment amount, and performing discharge for each cell for the determined discharge time. A technique for performing is known (see Patent Document 1).

JP-A-10-322925

  However, since the bypass current at the time of capacity adjustment fluctuates, in the conventional technology, the capacity between cells may not be uniform even after discharging for the discharge time determined based on the amount of bypass adjustment.

  The capacity adjustment device for a battery pack according to the present invention calculates the necessary capacity adjustment amount for each cell based on the open circuit voltage of each cell, and discharges for each cell. The discharge amount is calculated at the time of adjustment, and the cell is discharged until the calculated discharge amount matches the capacity adjustment amount.

  According to the battery pack capacity adjustment apparatus according to the present invention, the discharge amount is calculated when the capacity of each cell is adjusted, and the cells are discharged until the calculated discharge amount matches the capacity adjustment amount. Even if fluctuates, the capacity of each cell after capacity adjustment can be made uniform.

-First embodiment-
FIG. 1 is a diagram illustrating a configuration of a battery pack capacity adjustment device according to the first embodiment. This battery pack capacity adjustment device is mounted and used in, for example, a hybrid vehicle. The assembled battery 100 is, for example, a lithium ion battery, and is configured by connecting n (n: natural number) cells C1 to Cn that can be charged and discharged in series. Each of the cells C1 to Cn is grouped into four to constitute modules M1, M2,. The total voltage sensor 10 detects the total voltage of the assembled battery 100. The current sensor 20 detects the charge / discharge current of the assembled battery 100.

  The cell controllers CC1, CC2,..., CCt manage cells for each of the corresponding modules M1, M2,. For example, the cell controller CC1 controls charging / discharging of the four cells C1 to C4 included in the module M1.

  The battery controller 30 manages the assembled battery 100 by controlling the cell controllers CC1 to CCt. Moreover, the battery controller 30 communicates with each cell controller CC1-CCt by serial communication via the transmission terminal SD and the reception terminal RD.

  FIG. 2 is a diagram showing a detailed circuit configuration of the cell controller. Here, the cell controller CC1 will be described. However, the other cell controllers CC2 to CCt have the same circuit configuration. The cell controller CC1 includes an IC 11, an A / D converter 12, an interface (IF) 13, resistors R1 to R4, and switches S1 to S4.

  The A / D converter 12 converts the voltage between the terminals of each of the cells C1 to C4 into a digital signal and transmits it to the IC11. The interface 13 communicates with the battery controller 30 by serial communication. Note that the interface 13 and the IC 11 are insulated by a photocoupler 14. Further, the internal circuit of the assembled battery 100 has a high voltage of about 400 V at the maximum, and a capacity adjustment circuit constituted by wiring of a voltage detection circuit to the A / D converter 12 and resistors R1 to R4 and switches S1 to S4. Is built in the cell controller CC1 to avoid routing the high voltage circuit.

  A series circuit of a resistor and a switch is connected in parallel to each of the cells C1 to C4. A series circuit composed of a resistor and a switch is a capacity adjustment circuit for each cell. For example, a series circuit composed of a resistor R1 and a switch S1 constitutes a capacity adjustment circuit for the cell C1. The discharge capacity of each cell C1 to C4 can be adjusted via each resistor R1 to R4 to adjust the charge capacity of each cell. The switches S1 to S4 are controlled to be opened and closed by the IC 11, respectively. For example, when the switch S1 is closed, the cell C1 is discharged via the resistor R1.

  The resistance values of the resistors R1 to R4 are the same, for example, 200Ω. The capacity adjustment amount (discharge amount) of each cell depends on the closing time of the corresponding switches S1 to S4, and the capacity adjustment amount is controlled by controlling the switch opening and closing time. For example, in the case of a lithium ion battery, the capacity adjustment amount is, for example, about 0.1% or less of the rated capacity of the assembled battery 100, and can sufficiently suppress an increase in variation in the charge amount between cells.

  Here, a method of detecting the open voltages Vc1 to Vcn of the cells C1 to Cn will be described. The open-circuit voltages Vc1 to Vcn of the cells C1 to Cn are detected by an A / D converter of the cell controller, converted into a digital signal, sent to the IC of the cell controller CC, and further connected to the battery controller via the interface IF. 30.

The detection timing of the cell open voltages Vc1 to Vcn may be (I) immediately before the start of discharging the assembled battery 100, (II) a current decay region immediately before the end of full charge, (III) during discharging, or the like.
(I) Although the open circuit voltage can be detected at the timing immediately before the start of discharge, the voltage detection operation in each cell controller CC1 to CCt and the transmission operation of the detection result from each cell controller CC1 to CCt to the battery controller 30 Since the battery pack 100 must wait for the discharge from the assembled battery 100 to the load during the process, high-speed A / D conversion and communication speed are required. However, there are few restrictions on detection timing.
(II) Since the charging current is small in the current decay region immediately before the end of full charge, the voltage drop due to the internal resistance of each cell is small, and a voltage close to the open circuit voltage can be detected. Since it is during charging, it is not necessary to communicate with high-speed A / D conversion, but the detection timing is limited to the end of charging.
(III) During discharge, the discharge voltages Vc1 to Vcn and the discharge current I of each cell are measured, and the voltage-current characteristic (V = E-IR) for each cell is linearly regressed to estimate the open circuit voltage E of the cell. be able to. However, since the calculation is performed for each cell, the calculation load increases.

  Note that if the switches S1 to Sn are closed during the detection of the open circuit voltages Vc1 to Vcn and the cells are discharged by the resistors R1 to Rn, the measurement error of the open circuit voltage Vc becomes large. The closing of S1 to Sn is prohibited.

  Each cell controller CC1 to CCt detects the open voltage Vc1 to Vcn of each cell and sends it to the battery controller 30 via the interface IF. The battery controller 30 sets the minimum cell voltage among the open-circuit voltages Vc1 to Vcn acquired from the cell controllers CC1 to CCt to the capacity adjustment target voltage Vv, and sets the voltage of each cell to the value of the capacity adjustment target voltage Vv. Therefore, the bypass adjustment amounts (capacity adjustment amounts) Cct1 to Cctn necessary for this purpose are obtained.

  FIG. 3 is a diagram for obtaining the bypass adjustment amounts Cct1 to Cctn from the open-circuit voltages Vc1 to Vcn and the capacity adjustment target voltage Vv of each cell. For example, when the open circuit voltage of the cell is 3.45V and the capacity adjustment target voltage Vv is 3.25V, the bypass adjustment amount is 0.6 (= 1.6−1.0) Ah. The battery controller 30 stores the data shown in FIG. 3 in advance in a memory (not shown).

  In the battery pack capacity adjustment apparatus in the first embodiment, the discharge amount at the time of capacity adjustment is calculated for each predetermined period ΔT, and the calculated discharge amount is calculated based on the bypass adjustment amount Cct1 to Cct1. The switches S1 to Sn provided corresponding to the cells C1 to Cn are turned on until the Cctn is matched, and a bypass adjustment current is supplied. Here, the process of subtracting the discharge amount is repeatedly performed from the bypass adjustment amounts Cct1 to Cctn obtained based on the open circuit voltage of the cell, and the cell is discharged until the bypass adjustment amounts Cct1 to Cctn after the subtraction become zero. . The battery controller 30 performs processing for subtracting the bypass adjustment amounts Cct1 to Cctn.

For example, the bypass adjustment amount Cctn of the cell Cn is obtained by the following equation (1). In equation (1), the value obtained by multiplying the average bypass current value by the bypass time (discharge time) is the discharge amount at the time of capacity adjustment.
Cctn = Cctn−average bypass current In × bypass time (1)
However, the average bypass current In is a bypass current that flows when the capacity of the cell Cn is adjusted (during discharge), and the time average voltage Vcan of the cell Cn and the resistance of the resistor Rn provided corresponding to the cell Cn. Based on the value R, it can be obtained by the following equation (2).
In = Vcan / R (2)

A method for obtaining the time average voltage of each cell will be described. The battery controller 30 obtains the time average voltage of each cell by acquiring the voltage of each cell every predetermined period ΔT during capacity adjustment. For example, assuming that the voltages of the cells Cn detected at each predetermined period ΔT are Vcn_smp1, Vcn_smp2,. .
Vcan = (Vcn_smp1 + Vcn_smp2 + ... + Vcn_smpk) / k (3)

The calculation of the time average voltage according to the above equation (3) is performed for every predetermined period ΔT for all the cells C1 to Cn. In addition, the battery controller 30 performs abnormality determination based on the calculated time average voltages Vca1 to Vcan of each cell. Here, when the relationship of the following equation (4) is satisfied, no abnormality has occurred, and when the relationship of the equation (4) is not satisfied, sampling failure, cumulative error at voltage detection, voltage detection error For this reason, it is determined that the value of the time average voltage is abnormal. However, Vmin is a predetermined lower limit value, and Vmax is a predetermined upper limit value.
Vmin <Vca1, Vca2,..., Vcan <Vmax (4)

  When the time average voltages Vca1 to Vcan do not satisfy the relationship of Expression (4) and the value is determined to be abnormal, the value of the time average voltage determined to be abnormal is replaced with a predetermined value. The predetermined value is an average voltage value when charge / discharge control is performed, for example, a voltage value when the SOC of the cell is 50%.

  FIG. 4 is a flowchart showing the contents of processing performed in the battery pack capacity adjustment apparatus in the first embodiment. The process of step S1 to step S4 is a process performed by each cell controller CC1 to CCt, and the process of step S10 to step S100 is a process performed by the battery controller 30. When the system is turned on, each of the cell controllers CC1 to CCt starts the process of step S1.

  In step S1, the cell controllers CC1 to Cct detect the open voltages Vc1 to Vcn of the cells C1 to Cn, and the process proceeds to step S2. In step S <b> 2, the open-circuit voltages Vc <b> 1 to Vcn of each cell detected in step S <b> 1 are transmitted to the battery controller 30.

  In step S10, the battery controller 30 determines whether or not the open voltages Vc1 to Vcn of all the cells C1 to Cn have been received. If it is determined that the open voltages Vc1 to Vcn of all cells have not been received, the process waits in step S10. If it is determined that the open voltages Vc1 to Vcn of all cells have been received, the process proceeds to step S20.

  In step S20, among the open voltages Vc1 to Vcn of all cells received in step S10, the minimum cell voltage is set to the capacity adjustment target voltage Vv, and the process proceeds to step S30. In step S30, each cell is determined based on the open-circuit voltages Vc1 to Vcn and the capacity adjustment target voltage Vv of each cell, and data (see FIG. 3) relating to the bypass adjustment amount (capacity adjustment amount) stored in a memory (not shown). Bypass adjustment amounts Cct1 to Cctn necessary for aligning the voltage to the capacity adjustment target voltage Vv are obtained.

  In step S40 following step S30, time average voltages Vca1 to Vcan of each cell are obtained. As described above, the time average voltage is obtained for each cell based on the cell voltage detected every predetermined period Δt. When the time average voltage for each cell is obtained, the process proceeds to step S50. In step S50, it is determined whether or not an abnormality has occurred in the time average voltages Vca1 to Vcan obtained in step S40. As described above, if the time average voltage is larger than the predetermined lower limit value Vmin and smaller than the predetermined upper limit value Vmax, it is determined that the value of the time average voltage is normal, and is equal to or lower than the predetermined lower limit value Vmin, or When the value is equal to or higher than the predetermined upper limit value Vmax, it is determined that the value of the time average voltage is abnormal. If it is determined that the value of the time average voltage is abnormal, the process proceeds to step S60, and if it is determined to be normal, the process proceeds to step S70.

  In step S60, the value of the time average voltage determined to be abnormal is replaced with a predetermined value, and the process proceeds to step S70. In step S70, it is determined whether or not the bypass adjustment amounts Cct1 to Cctn of each cell are larger than zero. If it is determined that the bypass adjustment amount is greater than 0, the process proceeds to step S80. If it is determined that the bypass adjustment amount is 0 or less, the process proceeds to step S90. In step S80, a signal for turning on the switch provided corresponding to the cell for which the bypass adjustment amount is determined to be larger than 0 is transmitted to the cell controller managing the corresponding cell. On the other hand, in step S90, a signal for turning off the switch provided corresponding to the cell for which the bypass adjustment amount is determined to be 0 or less is transmitted to the cell controller managing the corresponding cell.

  In step S <b> 3, the cell controllers CC <b> 1 to CCt determine whether or not a signal for turning on / off the switches S <b> 1 to Sn is received from the battery controller 30. If it is determined that a signal for turning on / off the switches S1 to Sn is not received, the process waits in step S3. If it is determined that the signal is received, the process proceeds to step S4. In step S4, the switches S1 to Sn are turned on / off based on the received signal. For example, when the cell controller CC1 receives a signal for turning on the switch S2, the cell C2 is discharged by turning on the switch S2.

  When the battery controller 30 performs the process of step S80 or step S90, the process proceeds to step S100. In step S100, it is determined whether or not the bypass adjustment amounts of all the cells C1 to Cn have become zero. If it is determined that the bypass adjustment amount of all the cells is 0, the capacity adjustment process between the cells is terminated. On the other hand, if it is determined that at least one of the bypass adjustment amounts is not 0, the process returns to step S30 to perform processing for calculating the bypass adjustment amount. When the process returns from step S100 to step S30, the bypass adjustment amount is obtained by the above equation (1). Thereafter, the processes from step S30 to step S100 are repeatedly performed until the bypass adjustment amount of all the cells becomes zero.

  FIG. 5A shows the voltage of each cell before capacity adjustment, and FIG. 5B shows the capacity adjustment performed by the battery pack capacity adjustment apparatus according to the first embodiment. It is a figure which shows the voltage of each subsequent cell. As shown in FIG. 5B, each cell is discharged until the bypass adjustment amount calculated based on the open circuit voltage and the capacity adjustment target voltage Vv of each cell matches the discharge amount at the time of capacity adjustment. Thus, the cell voltage after capacity adjustment can be made uniform.

  According to the battery pack capacity adjustment apparatus in the first embodiment, the capacity adjustment amount necessary for each cell is calculated based on the open circuit voltage of each cell, and each cell is calculated based on the calculated capacity adjustment amount. Discharge each time. At this time, the discharge amount is calculated for each cell, and discharge is performed for each cell until the calculated discharge amount matches the capacity adjustment amount. Thereby, even if the bypass current fluctuates during capacity adjustment (discharge), the capacity of each cell can be made uniform.

  In particular, according to the battery pack capacity adjustment apparatus in the first embodiment, the time average cell voltage obtained based on a plurality of cell voltages detected at different timings for each cell, and the discharge of each cell. Based on the discharge resistance when performing, the discharge current at the time of discharge is calculated for each cell, and the discharge amount of each cell is calculated by integrating the calculated discharge current. By calculating the time average voltage of a cell based on a plurality of cell voltages detected at different timings for each cell, the discharge amount can be accurately calculated even when the cell voltage fluctuates.

  According to the battery pack capacity adjustment apparatus in the first embodiment, when the time average cell voltage obtained based on a plurality of cell voltages detected at different timings is equal to or lower than the predetermined lower limit value Vmin, the calculated time After the average voltage is replaced with a predetermined voltage value, the discharge current during discharge is calculated. Similarly, when the time average cell voltage obtained based on a plurality of cell voltages detected at different timings is equal to or higher than a predetermined upper limit value Vmax, the calculated time average voltage is replaced with a predetermined voltage value and then discharged. The discharge current is calculated. As a result, if the time average voltage value is abnormal due to sampling failure, cumulative error during voltage detection, voltage detection error, etc., an incorrect discharge amount is calculated based on the abnormal value. Can be prevented.

-Second Embodiment-
In the battery pack capacity adjustment apparatus according to the first embodiment, a time average voltage of a cell is calculated based on a plurality of cell voltages detected at different timings, and the calculated time average voltage and a discharge resistance at the time of discharge are calculated. The amount of discharge during capacity adjustment was calculated by calculating the discharge current. In the battery pack capacity adjustment apparatus in the second embodiment, instead of detecting the voltage of each cell, a plurality of total voltages of the battery pack 100 are detected at different timings, and based on the detected voltage values, The time average voltage of each cell is calculated.

In the battery pack capacity adjustment apparatus according to the second embodiment, the battery controller 30 acquires the total voltage of the battery pack 100 detected by the total voltage sensor 10 for each predetermined period ΔT during the capacity adjustment, and Find the time average voltage. For example, if the total voltage of the assembled battery 100 detected at each predetermined period ΔT is Vsum_smp1, Vsum_smp2,..., Vsum_smpk, the time average voltage Vcan of the cell is obtained by the following equation (5).
Vcan = (Vsum_smp1 + Vsum_smp2 + ... + Vsum_smpk) / n / k (5)
However, n is the number of cells constituting the assembled battery 100, and k is the total voltage sampling number.

  Compared with the method of calculating the time average voltage of each cell by detecting the voltage for each cell, the method of obtaining the time average voltage of the cell based on the total voltage of the assembled battery 100 is the time average of each cell. The accuracy of calculating the voltage is lowered. However, since the voltage variation of each cell is a very small value, the voltage difference between cells hardly affects the magnitude of the bypass current. For example, when the maximum value of the voltage difference between cells is 100 mV and the resistance value R of the resistors R1 to Rn provided corresponding to each cell is 200Ω, the difference in bypass current between the maximum voltage cell and the minimum voltage cell is 0.5 mA (= 100/200).

  In the battery pack capacity adjustment apparatus according to the second embodiment, since the time average voltage of the cell used when calculating the discharge amount at the time of capacity adjustment is calculated based on the total voltage of the battery pack 100, the cell time The calculation load when calculating the average voltage can be reduced.

-Third embodiment-
In the battery pack capacity adjustment apparatus according to the first embodiment, the voltage of each cell is detected for each predetermined period ΔT, the time average voltage of the cell is calculated based on the detected plurality of voltages, and the discharge time is discharged. The amount of discharge was determined. However, when the capacity adjustment is performed for each cell, when the discharge amount of a certain cell reaches the bypass adjustment amount and the capacity adjustment is completed, the voltage detection value of the cell adjacent to the cell where the capacity adjustment is completed Fluctuates. This will be described with reference to FIG.

  In FIG. 6, filters F1 to Fn for suppressing noise and surge are provided on connection lines connecting the cells C1 to Cn and the cell controllers CC1 to CCt. These filters F1 to Fn contain resistance components. For example, assuming that the resistance component of the filter F3 is Rf3 and the capacity adjustment of the cell C2 is performed by flowing the bypass current i2 from the cell C2, the capacity adjustment of the cell C2 is completed. The voltage varies by Rf3 × i2.

  Therefore, in the battery pack capacity adjustment apparatus according to the third embodiment, the time average voltage of the cells is calculated using a plurality of cell voltages detected in a state where the number of cells for which capacity adjustment is performed does not vary. . Thereby, since the calculation accuracy of the time average voltage of the cell can be improved, the calculation accuracy of the discharge amount at the time of capacity adjustment can also be improved. Since the battery controller 30 calculates the bypass adjustment amounts Cct1 to Cctn of each cell based on the formula (1), the timing at which the capacity adjustment cell number changes based on the bypass adjustment amounts Cct1 to Cctn. To grasp.

  FIG. 7 is a diagram showing a calculation range of cell voltage used for calculating a time average voltage of a cell among cell voltages detected every predetermined period (sampling period) ΔT. In FIG. 7, at times T1 and T2, the number of cells whose capacity is being adjusted changes. Therefore, when calculating the time average voltage of the cells, the cell voltage detected between time T1 and time T2 when the number of cells for which capacity adjustment is performed does not change is used. That is, using the cell voltages detected at the respective sample times Tsmp2, Tsmp3,..., Tsmp8, the time average voltage of the cells is calculated. In addition, since the number of cells for which capacity adjustment is performed has changed at time T2, the time average voltage is calculated using the cell voltage detected between time T2 and the time when the number of capacity adjustment cells changes next. calculate.

  According to the assembled battery capacity adjustment device in the third embodiment, the time average voltage of the cells is calculated based on the plurality of cell voltages detected in a state where the number of cells for which the capacity adjustment is performed does not change. More accurate time average voltage can be calculated. Thereby, since the calculation accuracy of the discharge amount at the time of capacity adjustment can be improved, the capacity adjustment accuracy can be further improved.

-Fourth embodiment-
The capacity adjustment of the cells C <b> 1 to Cn constituting the assembled battery 100 can be performed while the assembled battery 100 is being charged and discharged. However, immediately after switching from the state in which the assembled battery 100 is charged to the state in which discharge is performed, an accurate cell voltage cannot be detected due to a delay in the rise time of the discharge current. Moreover, immediately after switching from the state where the assembled battery 100 is discharged to the state where charging is performed, an accurate cell voltage cannot be detected due to a delay in the rise time of the charging current.

  Therefore, in the battery pack capacity adjustment apparatus according to the fourth embodiment, after the charge / discharge of the battery pack 100 is switched, the cell voltage detected within the predetermined time Tv is excluded, and the other cell voltages are set. Based on this, the time average voltage of the cell is calculated. Note that switching between charging and discharging of the assembled battery 100 is determined based on, for example, a current value detected by the current sensor 20.

  However, the period during which accurate cell voltage cannot be detected after charging / discharging has changed depends on the magnitude of the charging / discharging current value before switching to charging / discharging. The predetermined time Tv is changed based on the charge / discharge current value detected before the predetermined time Tx. Hereinafter, the predetermined time Tv is referred to as sampling ignorance time Tv.

  FIG. 8 shows the relationship between the charging current value detected before the predetermined time Tx and the sampling ignorance time Tv with reference to the timing when the battery pack 100 is charged to the discharged state. FIG. As shown in FIG. 8, the sampling ignorance time Tv is increased as the charging current value before switching from charging to discharging increases. Here, as shown in FIG. 8, data defining a correspondence relationship between the charging current value and the sampling ignorance time Tv is obtained in advance and stored in a memory (not shown) in the battery controller 30.

  FIG. 9 shows the relationship between the discharge current value detected before a predetermined time Tx and the sampling ignorance time Tv with reference to the timing when the battery pack 100 is discharged to the state where charging is performed. FIG. As shown in FIG. 9, the sampling ignorance time Tv is increased as the discharge current value before switching from discharging to charging increases. Here, data defining the correspondence between the discharge current value and the sampling ignorance time Tv as shown in FIG. 8 is obtained in advance and stored in a memory (not shown) in the battery controller 30.

  FIG. 10 is a diagram showing a calculation range of cell voltage used for calculating a time average voltage of a cell among cell voltages detected every predetermined period (sampling period) ΔT. Prior to time T3, the assembled battery 100 is charged, but after time T3, discharging is performed. The battery controller 30 converts the charging current value detected by the current sensor 20 before the predetermined time Tx from the time T3 and the charging current-sampling ignoring time Tv (see FIG. 8) stored in a memory (not shown). Based on this, the sampling ignore time Tv is determined. Then, the cell voltage value detected within the determined sampling ignorance time Tv from time T3 is excluded when calculating the time average voltage of the cell. In the example shown in FIG. 10, there is no cell voltage value detected within the sampling ignorance time Tv from time T3.

  The assembled battery 100 is discharged from the time T3 to the time T4 shown in FIG. 10, but is charged after the time T4. The battery controller 30 converts the discharge current value detected by the current sensor 20 before the predetermined time Tx from the time T4 and the data of the discharge current-sampling ignore time Tv (see FIG. 9) stored in a memory (not shown). Based on this, the sampling ignore time Tv is determined. Then, the cell voltage value detected within the determined sampling ignorance time Tv from time T4 is excluded when calculating the time average voltage of the cell. In the example shown in FIG. 10, since the cell voltage is detected once within the sampling ignorance time Tv from the time T4, the time average of the cells is based on a plurality of other cell voltage values excluding this cell voltage value. Calculate the voltage.

  According to the battery pack capacity adjustment apparatus of the fourth embodiment, within a predetermined time (sampling ignorance time Tv) after charging and discharging of the battery pack 100 among a plurality of cell voltages detected at different timings. Since the time average voltage is calculated by excluding the detected cell voltage, the accuracy of calculating the time average voltage of each cell can be improved. Thereby, since the calculation accuracy of the discharge current for each cell and the discharge amount during capacity adjustment can be improved, the capacity adjustment accuracy can be further improved.

  According to the assembled battery capacity adjusting apparatus in the fourth embodiment, when the assembled battery 100 is switched from the charged state to the discharged state, the sampling ignorance time Tv is set based on the charging current value before the switching. decide. In particular, the larger the charging current value, the longer the sampling ignore time Tv, so that it is possible to reliably exclude cell voltage values whose values are not accurate, and to exclude even accurate cell voltage values. Can be prevented. Similarly, when the assembled battery 100 is switched from the discharged state to the charged state, the sampling ignoring time Tv is determined based on the discharge current value before the switching. In particular, the larger the discharge current value, the longer the sampling ignore time Tv, so that it is possible to reliably exclude cell voltage values whose values are not accurate and to exclude even accurate cell voltage values. Can be prevented.

  The present invention is not limited to the embodiments described above. For example, in the first to fourth embodiments, the battery controller 30 performs the calculation of the time average voltage for each cell and the calculation of the bypass adjustment amounts Cct1 to Cctn. However, even if the cell controllers CC1 to CCt perform the calculation. Good.

  As the capacity adjustment target voltage Vv, the minimum cell voltage is set among the open voltages Vc1 to Vcn of the cells C1 to Cn, but may be set to a voltage value different from the minimum cell voltage.

  In each of the above-described embodiments, an example in which the battery pack capacity adjustment device is applied to a hybrid vehicle has been described. The capacity adjustment of each of the cells C1 to Cn can be performed even when the vehicle is keyed off. However, if various calculations are performed every predetermined time, the battery power consumption at the time of keyoff increases. Therefore, a clock generation circuit is provided in the circuit, and various operations are performed based on the operation clock signal generated by the clock generation circuit. When the vehicle is keyed off, the operation clock signal generation interval is lengthened to reduce power consumption. May be reduced. FIG. 11 is a diagram illustrating a circuit configuration in which each of the cell controllers CC1 to CCt operates based on the operation clock signal generated by the clock generation circuit 50. In the circuit configuration shown in FIG. 11, the battery controller 30 lengthens the generation interval of the operation clock signal generated by the clock generation circuit 50 when the vehicle is keyed off. Thereby, reduction of the battery power at the time of key-off can be suppressed. FIG. 12 shows an example in which the cell controller CC1 to CCt controls the generation timing of the operation clock signal generated by the clock generation circuit. In this case, each cell controller CC1 to CCt may increase the generation interval of the operation clock signal generated by the clock generation circuit when the vehicle is keyed off.

  In the battery pack capacity adjustment apparatus according to the fourth embodiment, the cell voltage value detected within the sampling ignorance time Tv after the charge / discharge of the battery pack 100 is switched is calculated when the time average voltage of the cell is calculated. Excluded. In contrast to this method, when charging / discharging of the assembled battery 100 is switched, the detection of the cell voltage may be stopped, and the cell voltage detection process may be started again after the sampling ignoring time Tv has elapsed. According to this method, since the cell voltage is not detected within the sampling ignorance time Tv after the charge / discharge is switched, the process of excluding a specific detection voltage value from the detection voltage is omitted. Can do. FIG. 13 is a diagram illustrating a state in which the detection of the cell voltage is stopped when charging / discharging of the assembled battery 100 is switched, and the cell voltage detection process is started again after the sampling ignoring time Tv has elapsed.

  In the battery pack capacity adjustment apparatus according to the fourth embodiment, the data (see FIG. 8) defining the correspondence between the charging current value detected before the charge / discharge switching and the sampling ignorance time Tv, and the charge / discharge The data (see FIG. 9) defining the correspondence between the discharge current value detected before switching and the sampling ignorance time Tv is prepared in advance and stored in a memory (not shown) of the battery controller 30. However, it is also possible to prepare only one piece of data that defines the correspondence between the charge / discharge current value and the sampling ignorance time Tv, and use it together when detecting the charge current and detecting the discharge current. However, when the charge characteristic and the discharge characteristic are different, it is preferable to prepare two data, that is, data used when switching from charging to discharging and data used when switching from discharging to charging.

  In the battery pack capacity adjustment apparatus according to the third embodiment, the time average voltage of the cells is calculated based on a plurality of cell voltages detected in a state where the number of cells for which capacity adjustment is performed does not change, In the assembled battery capacity adjustment device in the embodiment, the cell voltage detected within a predetermined time after the charge / discharge of the assembled battery 100 is switched is excluded, and the time average voltage is calculated. The features of the third and fourth embodiments can be combined. That is, out of a plurality of cell voltages detected in a state where the number of cells for which capacity adjustment is performed does not change, the cell voltage detected within a predetermined time after the charge / discharge of the assembled battery 100 is switched is excluded. An average voltage can be calculated.

  Although a lithium ion battery has been described as an example of the assembled battery 100, the present invention is not limited by the type of the assembled battery. For example, the assembled battery may be a nickel metal hydride battery or a lead acid battery.

  The correspondence between the constituent elements of the claims and the constituent elements of the first to fourth embodiments is as follows. That is, the cell controllers CC1 to CCt are cell voltage detection means, the battery controller 30 is a capacity adjustment amount calculation means, a discharge amount calculation means, an average voltage calculation means, a discharge current calculation means, a charge / discharge switching detection means, a predetermined time determination means, The voltage replacement means includes cell controllers CC1 to CCt, resistors R1 to Rn, and switches S1 to Sn as discharge control means, the total voltage sensor 10 as total voltage detection means, and the current sensor 20 as current detection means. Configure each. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

The figure which shows the structure of the capacity | capacitance adjustment apparatus of the assembled battery in 1st Embodiment. Diagram showing detailed circuit configuration of cell controller Diagram for determining the amount of bypass adjustment from the open circuit voltage and capacity adjustment target voltage of each cell The flowchart which shows the processing content performed with the capacity adjustment apparatus of the assembled battery in 1st Embodiment. FIG. 5A shows the voltage of each cell before capacity adjustment, and FIG. 5B shows the capacity adjustment performed by the battery pack capacity adjustment apparatus according to the first embodiment. The figure which shows the voltage of each cell after The figure for demonstrating that the voltage detection value of a cell is fluctuate | varied by the change of the capacity adjustment cell number The figure which shows the calculation application range of the cell voltage used in order to calculate the time average voltage of a cell among the cell voltages detected for every predetermined period The figure which shows the relationship between the charging current value detected before predetermined time, and the sampling ignorance time on the basis of the timing which switched from the state in which the assembled battery is being charged to the state in which it is discharged The figure which shows the relationship between the discharge current value detected a predetermined time ago and sampling ignorance time on the basis of the timing which switched from the state in which an assembled battery is discharged to the state in which charging is performed The figure which shows the calculation application range of the cell voltage used in order to calculate the time average voltage of a cell among the cell voltages detected for every predetermined period The figure which shows the circuit structure which each cell controller operate | moves based on the operation clock signal produced | generated by the clock generation circuit based on the instruction | indication from a battery controller. The figure which shows the circuit structure which each cell controller operate | moves based on the operation clock signal produced | generated by the clock generation circuit based on the instruction | indication from a cell controller. The figure which shows a mode that the detection of a cell voltage is stopped when charge / discharge of an assembled battery switches, and the detection process of a cell voltage is started again after sampling ignorance time progress.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Total voltage sensor, 11 ... IC, 12 ... A / D converter, 13 ... Interface, 20 ... Current sensor, 30 ... Battery controller, 50 ... Clock generation circuit, 100 ... Assembly battery, CC1-CCt ... Cell controller, R1 ~ Rn ... resistor, S1-Sn ... switch

Claims (12)

In an apparatus for adjusting the capacity between a plurality of cells constituting an assembled battery,
Cell voltage detection means for detecting the voltage of each cell;
Capacity adjustment amount calculating means for calculating a capacity adjustment amount necessary for each cell based on the open circuit voltage of each cell detected by the cell voltage detecting means;
Discharge control means for performing discharge for each cell based on the capacity adjustment amount calculated by the capacity adjustment amount calculation means;
A discharge amount calculating means for calculating a discharge amount of each cell during discharge by the discharge control means;
For each cell, and the cell based on the cell voltages detected at different timings by the voltage detecting means, that to calculate the time average voltage average voltage calculating means,
Based on the time average voltage calculated by the average voltage calculation means and the discharge resistance at the time of discharge of each cell, the discharge current calculation means for calculating the discharge current at the time of discharge for each cell , and
The discharge amount calculation means calculates the discharge amount of each cell by integrating the discharge current calculated by the discharge current calculation means,
The discharge control means discharges each cell until the discharge amount calculated by the discharge amount calculation means matches the capacity adjustment amount calculated by the capacity adjustment amount calculation means. Capacity adjustment device. The capacity adjustment apparatus for an assembled battery according to claim 1 ,
The battery pack capacity adjustment device, wherein the average voltage calculation means calculates a time average voltage for each cell based on a plurality of cell voltages detected every predetermined time by the cell voltage detection means. The capacity adjustment apparatus of the assembled battery according to claim 1 or 2 ,
The average voltage calculation means calculates a time average voltage based on a plurality of cell voltages detected at different timings by the cell voltage detection means in a state where the number of cells for which capacity adjustment is performed does not change. The capacity adjustment device of the assembled battery. The capacity adjustment apparatus of the assembled battery according to claim 1 or 2 ,
It further comprises charge / discharge switching detecting means for detecting switching of charging and discharging of the assembled battery,
When the charging / discharging switching detecting unit detects charging and discharging switching of the assembled battery, the average voltage calculating unit is configured to charge and out of a plurality of cell voltages detected at different timings by the cell voltage detecting unit. An assembled battery capacity adjustment device, wherein the time average voltage is calculated by excluding cell voltages detected within a predetermined time after the discharge is switched. The capacity adjustment device for an assembled battery according to claim 4 ,
Current detection means for detecting charge / discharge current of the assembled battery;
And a predetermined time determining means for determining the predetermined time based on the charging current value detected by the current detecting means before the charge / discharge switching detecting means detects the switching from charging to discharging. A battery pack capacity adjusting device characterized by the above. In the capacity adjustment apparatus of the assembled battery according to claim 5 ,
The battery pack capacity adjustment device according to claim 1, wherein the predetermined time determination means lengthens the predetermined time as the charging current value detected by the current detection means increases. The capacity adjustment device for an assembled battery according to claim 4 ,
Current detection means for detecting charge / discharge current of the assembled battery;
And a predetermined time determining means for determining the predetermined time based on the discharge current value detected by the current detecting means before the charge / discharge switching detecting means detects the switching from discharging to charging. A battery pack capacity adjusting device characterized by the above. In the assembled battery capacity adjustment device according to claim 7 ,
The capacity adjustment device for a battery pack according to claim 1, wherein the predetermined time determination means lengthens the predetermined time as the discharge current value detected by the current detection means increases. In an apparatus for adjusting the capacity between a plurality of cells constituting an assembled battery,
Cell voltage detection means for detecting the voltage of each cell;
Capacity adjustment amount calculating means for calculating a capacity adjustment amount necessary for each cell based on the open circuit voltage of each cell detected by the cell voltage detecting means;
Discharge control means for performing discharge for each cell based on the capacity adjustment amount calculated by the capacity adjustment amount calculation means;
A discharge amount calculating means for calculating a discharge amount of each cell during discharge by the discharge control means;
Total voltage detecting means for detecting the total voltage of the assembled battery;
Average voltage calculating means for calculating a time average voltage of the cell based on a plurality of total voltages detected at different timings by the total voltage detecting means;
Based on the time average voltage calculated by the average voltage calculation means and the discharge resistance when discharging each cell, the discharge current calculation means for calculating the discharge current at the time of discharge for each cell , and
The discharge amount calculation means calculates the discharge amount of each cell by integrating the discharge current calculated by the discharge current calculation means,
The discharge control means discharges each cell until the discharge amount calculated by the discharge amount calculation means matches the capacity adjustment amount calculated by the capacity adjustment amount calculation means. Capacity adjustment device. The capacity adjustment device for an assembled battery according to claim 9 ,
The battery pack capacity adjustment device, wherein the average voltage calculation means calculates a time average voltage of each cell based on a plurality of total voltages detected every predetermined time by the total voltage detection means. In the battery pack capacity adjustment device according to any one of claims 1 to 10 ,
When the time average voltage calculated by the average voltage calculation means is equal to or lower than a predetermined lower limit value, the apparatus further comprises voltage replacement means for replacing the calculated time average voltage with a predetermined voltage value,
The discharge current calculation means, the predetermined voltage value is replaced by the voltage substitution means, and, based on the discharge resistance during discharge of each cell, for each cell, and characterized in that calculating the discharge current during discharge The capacity adjustment device of the assembled battery. In the battery pack capacity adjustment device according to any one of claims 1 to 10 ,
When the time average voltage calculated by the average voltage calculation means is equal to or higher than a predetermined upper limit value, the apparatus further comprises voltage replacement means for replacing the calculated time average voltage with a predetermined voltage value.
The discharge current calculation means, the predetermined voltage value is replaced by the voltage substitution means, and, based on the discharge resistance during discharge of each cell, for each cell, and characterized in that calculating the discharge current during discharge The capacity adjustment device of the assembled battery.

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