JP2020043763A - Power storage state adjustment device, battery pack, load system, and power storage state adjustment method - Google Patents

Abstract

To provide a power storage state adjustment device capable of improving charge/discharge efficiency.SOLUTION: A power storage state adjustment device is configured to adjust a power storage state of a battery pack 100 in which a plurality (e.g., four) of storage batteries BAT1-BAT4 are connected in series. The power storage state adjustment device comprises: a primary-side coil that is connected in series with the plurality of storage batteries; a plurality of secondary-side coils which are connected respectively in parallel with the plurality of storage batteries and to which energy stored in the primary-side coil is transferred; and a cell balance control system for setting a target value (balance time target value) of balance time that is time from charge start or discharge start of the battery pack 100 to balancing voltage of the plurality of storage batteries when not charging or discharging the battery pack, and adjusting the quantity of total energy to be stored in the primary-side coil on the basis of the target value.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a storage state adjustment device, a battery pack, a load system, and a storage state adjustment method.

  2. Description of the Related Art In recent years, techniques for charging and discharging a battery pack in which a plurality of storage batteries are connected in series have been actively developed.

  For example, Patent Literature 1 discloses a technique of adjusting a charging current and a discharging current to equalize the battery voltage of each storage battery when charging and discharging the assembled battery.

  However, the technique disclosed in Patent Literature 1 has room for improvement with respect to improvement of charging and discharging efficiency.

  The present invention is a storage state adjustment device that adjusts the storage state of a battery pack in which a plurality of storage batteries are connected in series, and controls a current for balancing voltages of the plurality of storage batteries during charging and discharging of the battery pack. A current supply circuit for supplying the battery pack, and set a target value of a balance time that is a time period from the start of charging or the start of discharging of the battery pack until the voltages of the plurality of storage batteries are balanced, based on the target value. A control system for controlling the current supply circuit, wherein the current supply circuit is connected in parallel to each of the plurality of storage batteries and a primary coil connected in series to the plurality of storage batteries, and the primary side is connected to each of the plurality of storage batteries in parallel. A plurality of secondary-side coils to which energy stored in the coil is transmitted, and the control system sets the target value and sets the target value based on the target value other than during charging and discharging of the battery pack. The primary side A state of charge adjustment device for setting the total amount of energy accumulated in the file.

  According to the present invention, the charge / discharge efficiency can be improved.

It is a figure which shows the time change of the cell voltage (battery voltage) when the cell balance method is not introduced. FIGS. 2A and 2B are diagrams illustrating the battery packs 1 ′ and 2 ′ (fixed cell balance current) of the comparative example, respectively. FIGS. 3A and 3B are diagrams illustrating the battery packs 1 and 2 (variable cell balance current) of the first and second embodiments, respectively. FIG. 3 is a block diagram illustrating a configuration of a cell balance control system of Example 1 of the first embodiment. FIG. 4 is a circuit diagram showing a configuration of a variable constant current circuit connected to a primary coil. FIG. 6 is a diagram illustrating a change over time of a cell voltage when a cell is balanced in a relatively short time with respect to a charging time. It is a figure which shows the time change of the cell voltage at the time of carrying out cell balance just before a charging time. It is a flowchart for demonstrating a pre-cell balance process. 6 is a flowchart for describing a power storage state adjustment process according to the first embodiment. FIG. 4 is a block diagram illustrating a configuration of a cell balance control system according to a second example of the first embodiment. 9 is a flowchart for describing a storage state adjustment process according to the second embodiment. FIG. 9 is a block diagram illustrating a configuration of a cell balance control system according to a third example of the first embodiment. 13 is a flowchart illustrating a power storage state adjustment process according to a third embodiment. FIG. 9 is a block diagram illustrating a configuration of a cell balance control system according to a fourth example of the first embodiment. FIG. 13 is a block diagram illustrating a configuration of a cell balance control system according to a fifth example of the first embodiment. FIG. 9 is a block diagram illustrating a configuration of a cell balance control system according to a first example of the second embodiment. FIG. 13 is a block diagram illustrating a configuration of a cell balance control system of Example 2 of the second embodiment. FIG. 13 is a block diagram illustrating a configuration of a cell balance control system according to a third example of the second embodiment. FIG. 14 is a block diagram illustrating a configuration of a cell balance control system according to Example 4 of the second embodiment. FIG. 14 is a block diagram illustrating a configuration of a cell balance control system according to a fifth example of the second embodiment.

  Hereinafter, the power storage state adjusting devices according to the first and second embodiments of the present invention will be described with reference to the drawings.

  The power storage state adjusting devices of the first and second embodiments are devices that adjust the power storage state during charging and discharging of a battery pack in which a plurality of storage batteries (also referred to as secondary batteries or batteries) are connected in series.

  FIG. 1 shows a case where the battery voltage (cell voltage) is not balanced between storage batteries during charging and discharging of the assembled battery.

  If the battery voltage is not balanced between the storage batteries at the time of charging / discharging the assembled battery as described above, due to variation in the capacity between the storage batteries, even if the same power is charged / discharged, some storage batteries will be overcharged / overdischarged. come. When the storage battery is in an overcharged state or an overdischarged state, power loss, life degradation, and safety problems occur.

  Therefore, in recent years, the development of a cell balance method for balancing the battery voltage between the storage batteries at the time of charging and discharging the assembled battery has been actively performed. Among the cell balance methods, an active cell balance method, which can achieve high efficiency and a short cell balance in a short time, has attracted attention.

  FIGS. 2A and 2B show battery packs 1 ′ and 2 ′ of Comparative Examples 1 and 2, respectively, in which the active cell balance method is introduced. Hereinafter, the same components in Comparative Examples 1 and 2 are given the same reference numerals and described.

  As shown in FIG. 2A, the battery pack 1 'of Comparative Example 1 includes an assembled battery 100, a flyback transformer, a storage state adjustment circuit, a P + terminal, a P- terminal, and the like.

  The storage state adjustment circuit equalizes the battery voltage of the plurality of storage batteries (secondary batteries) included in the assembled battery 100 and adjusts the state of accumulation of electricity (that is, the state of storage) in each storage battery.

  The storage state adjustment circuit has a primary side drive unit and a secondary side distribution / discharge unit.

  The primary side drive unit has a cell balance controller CBC1 'and a drive switch element SW, and serves as a primary side energy storage source. The driving switch element SW is, for example, a semiconductor switch element such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), a junction FET, a bipolar transistor, or the like.

  The secondary-side distribution / discharge unit includes diodes D1, D2, D3, and D4, and discharges power (energy) to the storage batteries and redistributes them.

  In the battery pack 1 ′, the assembled battery 100 connected to the storage state adjusting device circuit includes a plurality of (n) chargeable / dischargeable storage batteries (also referred to as battery cells, secondary batteries, and power storage means) BAT1 to BATn (here, BAT1 to BATn). Four storage batteries BAT1, BAT2, BAT3, and BAT4).

  In the flyback transformer, the primary coil LP is a primary inductor, and the secondary coils L1, L2, L3, and L4 are secondary inductors.

  The storage state adjustment circuit constitutes a flyback converter circuit. In the primary side driving unit, energy is supplied from the positive electrode of the battery pack 100, the cell balance controller CBC1 'controls the drive switch element SW, and the energy set by the cell balance controller CBC1' during the ON period of the drive switch element SW. Is stored in the primary coil LP.

  Since the primary coil LP is connected to the positive electrode of the battery pack 100, energy is supplied from the charger and the whole battery pack 100 during charging. When the drive switch element SW is turned off, the energy supplied to the primary coil LP is redistributed (output) to the secondary coils L1 to L4, and the charger in which the secondary coils L1 to L4 are redistributed. And the energy comprising the battery voltage is supplied to the storage battery having a low battery voltage.

  The primary coil LP receives energy supply from the entire battery pack 100 when a load is connected. The energy supplied to the primary coil LP is redistributed to the secondary coils L1 to L4 when the drive switch element SW is OFF, and the energy is supplied from the battery voltage to which the secondary coils L1 to L4 are redistributed. Energy is supplied to a storage battery with a low battery voltage.

  The secondary-side distribution / discharge unit is a discharge / redistribution unit. When the drive switch element SW is turned off, the energy stored in the primary-side coil LP is stored in the corresponding storage batteries BAT1 to BAT4 through the diodes D1, D2, D3, and D4. To discharge.

  The flyback transformer stores energy in the primary coil LP during the ON period of the drive switch element SW. Then, when the drive switch element SW is turned off, the flyback transformer outputs the energy stored using the back electromotive energy of the primary coil LP to the secondary coils L1, L2, L3, L4 at a stretch. .

  In Comparative Example 1, a device including a storage state adjustment circuit and a flyback transformer is referred to as a “storage state adjustment device” (the same applies to Comparative Examples 2, 1 and 2 described below). The P + terminal of the battery pack 1 'is connected to the positive electrode of the charger or load, and the P- terminal is connected to the negative electrode of the charger or load.

  In the assembled battery 100, the storage batteries BAT1, BAT2, BAT3, and BAT4 are connected in series, the positive electrode of the storage battery BAT4 is connected to the P + terminal, and the negative electrode of the storage battery BAT1 is connected to the P- terminal.

  The positive electrode of the storage battery BAT4 of the battery pack 100 is connected to one end of the primary coil LP, and the other end of the primary coil LP is connected to one end of the drive switch element SW. The other end of the drive switch element SW is connected via a resistor R to the negative electrode of the storage battery BAT1.

  One end of the secondary coil L1 is connected to the negative electrode of the storage battery BAT1, and the other end is connected to the positive electrode of the storage battery BAT1 via the diode D1. One end of the diode D1 is connected to the other end of the secondary coil L1, and the other end is connected to the positive electrode of the storage battery BAT1.

  One end of the secondary coil L2 is connected to the positive electrode of the storage battery BAT1 and the negative electrode of the storage battery BAT2, and the other end is connected to the positive electrode of the storage battery BAT2 via the diode D2. One end of the diode D2 is connected to the other end of the secondary coil L2, and the other end is connected to the positive electrode of the storage battery BAT2.

  One end of the secondary coil L3 is connected to the positive electrode of the storage battery BAT2 and the negative electrode of the storage battery BAT3, and the other end is connected to the positive electrode of the storage battery BAT3 via the diode D3. One end of the diode D3 is connected to the other end of the secondary coil L3, and the other end is connected to the positive electrode of the storage battery BAT3.

  One end of the secondary coil L4 is connected to the positive electrode of the storage battery BAT3 and the negative electrode of the storage battery BAT4, and the other end is connected to the positive electrode of the storage battery BAT4 and the P + terminal via the diode D4. One end of the diode D4 is connected to the other end of the secondary coil L4, and the other end is connected to the positive electrode and the P + terminal of the storage battery BAT4.

  The cell balance controller CBC1 'generates and outputs a switch element control signal Scon for controlling ON / OFF of the drive switch element SW. Specifically, the switch element control signal Scon is, for example, a rectangular pulse signal for turning on the drive switch element SW at a predetermined timing.

  One end of the resistor R is connected to the cell balance controller CBC1 'and the drive switch element SW. The other end of the resistor R is connected to the P- terminal.

  In the battery pack 2 'of Comparative Example 2, the primary coils LP1, LP2, LP3, and LP4 are primary inductors of the flyback transformers 1 to 4, respectively, and the secondary coils L1, L2, L3, and L4 are flyback transformers. These are the secondary side inductors 1 to 4. Further, resistors R1 to R4 are provided corresponding to the flyback transformers 1 to 4, respectively.

  The storage state adjusting circuit of Comparative Example 2 forms a flyback converter circuit. In the primary drive unit, energy is supplied from the charger and the entire battery pack 100, and the cell balance controller CBC2 'individually controls the four drive switch elements SW1 to SW4 corresponding to the four primary coils LP1 to LP4. Then, the energy set by the cell balance controller CBC2 'is stored in the corresponding primary coil during the ON period of at least one drive switch element.

  In Comparative Example 2, the measurement values of the voltage sensors VS1 to VS4 that measure the battery voltages of the four storage batteries BAT1 to BAT4 are sent to the cell balance controller CBC2 ′. The drive switch element corresponding to the storage battery having the lower battery voltage is turned ON, and energy is stored in the corresponding primary coil.

  Since each primary coil is connected to the positive electrode and the P + terminal of the battery pack 100, at least one primary coil receives energy supply from the entire battery pack 100 and the charger during charging. The energy supplied to the at least one primary coil is redistributed (output) to the corresponding secondary coil when the corresponding drive switch element is turned off, and the secondary coil is re-distributed. And the energy comprising the battery voltage is supplied to the storage battery having a low battery voltage.

  Also, at least one primary coil receives energy supply from the entire battery pack 100 when a load is connected. The energy supplied to at least one primary coil is redistributed to the secondary coils L1 to L4 when the corresponding drive switch element SW is OFF, and the secondary coils L1 to L4 are redistributed. Energy consisting of the battery voltage is supplied to a storage battery having a low battery voltage.

  According to the power storage state adjusting devices of Comparative Examples 1 and 2 described above, a constant current (cell balance current) can be selectively supplied to the secondary coils L1 to L4 via at least one primary coil. And cell balance can be achieved.

  Meanwhile, as an important need for a storage battery, it is desired that the driving time of a device (load) can be utilized as long as possible by one charge. In addition, for an automobile that can charge gasoline in a few minutes, in order to spread an electric automobile driven by a storage battery, there is a problem that the charging time is usually longer than one hour. .

  As a countermeasure against this problem, it is conceivable to increase the cell balance current to the storage batteries of the assembled batteries of the battery packs 1 ′ and 2 ′ of Comparative Examples 1 and 2. However, this leads to an increase in the size of the circuit and an increase in power loss. Is concerned.

  More specifically, it is necessary to flow a larger current than usual during high-speed charging and discharging. For example, to fully charge a storage battery in five minutes, it is necessary to charge and discharge at a rate 12 times as fast as charging the storage battery in one hour. It is necessary to flow a current 12 times as large as the current value, and it is necessary to increase the cell balance current in order to complete the cell balance rapidly. The energy loss of the storage battery is a value obtained by multiplying the square of the current flowing through the internal resistance of the circuit and the storage battery by the sum of the circuit resistance and the internal resistance.

However, when a large cell balance current is passed to ensure high-speed charging, energy loss (power loss) increases. For example, the energy loss (NI) ² × R × t = NI × NIRt when the cell balance current I is multiplied by N is obtained, and the energy loss when the cell balance current I is I × R × Nt = NIR is NI times.

  Therefore, the inventor has proposed a battery pack 1 according to the first and second embodiments shown in FIGS. 3A and 3B, respectively, as a battery pack for high-speed charging capable of suppressing an increase in size and an increase in power loss. 2 has been developed. In the following description of the first and second embodiments, the same components as those in Comparative Examples 1 and 2 are denoted by the same reference numerals.

  The battery packs 1 and 2 of the first and second embodiments are obtained by improving the battery packs 1 ′ and 2 ′ of Comparative Examples 1 and 2, respectively.

  That is, the battery pack 1 of the first embodiment is provided with a variable constant current circuit 400 instead of the drive switch element SW as can be seen from FIG. As can be seen from FIG. 4 showing the cell balance control system, the cell balance controller CBC1 includes a voltage monitoring unit 500, a balance time target value setting unit 600, a coil current control unit 700, a storage unit 800, and a timer 900. It differs from the battery pack 1 'of Comparative Example 1 in that four voltage sensors VS1 to VS4 for respectively measuring the battery voltages of the storage batteries BAT1 to BAT4 are provided.

  The variable constant current circuit 400 functions as a current adjustment unit that adjusts a current flowing through the primary coil LP, that is, an energy adjustment unit that adjusts energy stored in the primary coil LP.

  As shown in FIG. 5, variable constant current circuit 400 includes a variable current source 400a and a current mirror circuit having two MOSFETs 400b and 400c. Note that a junction FET or a bipolar transistor may be used instead of the MOSFET.

  The two MOSFETs 400b and 400c have their gates connected to each other and their drains connected to each other.

  In the MOSFET 400b, the source and the gate are connected (short-circuited), and the source is connected to the positive electrode of the variable current source 400a. When the current from the variable current source 400a flows as the reference current Iref between the source and the drain of the FET 400b, the output current Iout obtained by copying the reference current Iref flows between the source and the drain of the FET 400c. The output current Iout is supplied to the primary coil LP. The magnitude of the reference current Iref and thus the output current Iout is determined by the coil current set value sent from the coil current controller 700 of the cell balance controller CBC1 to the variable current source 400a.

  The voltage monitoring unit 500 monitors (monitors) the measurement values of the four voltage sensors VS1 to VS4, and obtains a difference between the battery voltages (cell voltages) of the plurality of storage batteries BAT1 to BAT4 as needed, and obtains a balance time target value setting unit 600. Output to

  Here, the difference between the battery voltages of the plurality of storage batteries may be the difference between the battery voltages of the storage battery with the highest or lowest battery voltage and the other storage batteries, or the difference between the battery voltage of each storage battery and the other storage batteries. May be. Further, instead of the difference between the battery voltages of the plurality of storage batteries, for example, a difference between the battery voltage of each storage battery and the average value of the battery voltage of the plurality of storage batteries may be used.

  The balance time target value setting section 600 sets a balance time target value BTt which is a target value of the balance time BT which is a time from the start of charging or discharging of the battery pack 100 to the time when the voltages of the plurality of storage batteries are balanced.

  More specifically, the balance time target value setting unit 600 determines the difference between a plurality of battery voltages from the voltage monitoring unit 500 when the charger and the load are not connected to the battery pack 1 and the current stored in the storage unit 800. Based on upper limit value Imax, charging time CT, and discharging time DCT, balance time target values BTt-C and BTt-DC during charging and discharging are calculated and stored in storage section 800. The storage unit 800 includes, for example, a memory and a hard disk.

  Specifically, the balance time target value BTt-C at the time of charging is a time equal to or less than the charging time CT (eg, 64 ms), and is equal to or less than the current upper limit value Imax (eg, 44 A) from the beginning of charging (eg, at the start of charging). By supplying the coil current to the primary coil LP, the time can be calculated and set as the time during which the battery voltages of the four storage batteries BAT1 to BAT4 can be balanced (see FIGS. 6 and 7).

  FIG. 6 shows an example in which the cell balance is performed in a relatively short time with respect to the charging time CT (about 64 ms). Here, the balance time target value BTt-C is calculated and set to about 56 ms. I have.

  FIG. 7 shows an example in which cell balancing is performed at substantially the same time as the charging time CT (about 64 ms). Here, the balance time target value BTt-C is calculated and set to about 64 ms.

  Note that the balance time target value BTt-DC at the time of discharging can also be calculated and set based on the discharging time as in the case of charging. 6 and 7, the voltage at which the battery voltages of the plurality of storage batteries are balanced (substantially coincide with each other) is 3.3 V to 3.6 V.

Here, each balance time target value is a total energy storage amount (W = ∫1 / 2LI ² , where L is a self-inductance, and I is a current) from a charge start or a discharge start to the balance time target value. ) Is set to be equal to or less than the intermediate value between the maximum value and the minimum value of the total energy storage amount when an arbitrary time from the start of charging to the charging time CT or the discharging time DCT is set as the balance time target value. Is most preferable, and is most preferably set to be the minimum value.

  The coil current control unit 700 determines the difference between the battery voltage (cell voltage) from the voltage monitoring unit 500 when the charger and the load are not connected to the battery pack 1, the current upper limit value Imax stored in the storage unit 800, A coil current amount (coil current value × supply time) to be supplied to the primary coil LP at the time of charging and discharging is calculated based on the charging time CT, the discharging time DCT, the balance time target value BTt-C, BTt-DC, Then, the set value of the coil current amount during charging and discharging is stored in the storage unit 800.

  Further, the coil current control unit 700 reads the corresponding set value of the coil current amount from the storage unit 800 at the time of charging when the battery pack 1 is connected to the charger or at the time of discharging when the battery pack 1 is connected to the load (device). Then, a drive signal (a pulse signal of a predetermined cycle in which the coil current value is pulse amplitude and the supply time is pulse width) according to the set value is sent to the variable constant current circuit 400. The variable constant current circuit 400 supplies the set coil current amount to the primary coil LP.

  Note that a detection signal or a non-detection signal from the charger / load connection detection unit 960 is transmitted to the coil current control unit 700. The charger / load connection detection unit 960 detects whether a charger or a load is connected to the battery pack 1 based on a change in voltage between the P + terminal and the P− terminal. That is, when the change in the voltage between the P + terminal and the P- terminal is large, the presence or absence of the connection of the charger can be detected, and when the change is small, the presence or absence of the connection of the load can be detected.

  Hereinafter, the pre-cell balance processing by the cell balance control system of Example 1 of the battery pack 1 of the first embodiment will be described with reference to the flowchart of FIG. This pre-cell balance processing is repeatedly performed in a state where the battery pack 1 is not connected to the charger or the load, that is, other than during charging and discharging. That is, the pre-cell balance processing is performed at a time other than the time of charging and discharging, for example, after a lapse of several minutes to several hours from the previous time.

  In the first step S <b> 1, the voltage monitoring unit 500 calculates a difference between the battery voltages of the plurality of storage batteries from the measured values of the plurality of voltage sensors V <b> 1 to V <b> 4, and outputs the difference to the balance time target value setting unit 600.

  In the next step S2, the balance time target value setting unit 600 sets the balance time target values during charging and discharging based on the difference between the battery voltages of the plurality of storage batteries, the charging time CT and the discharging time DCT, and the current upper limit value Imax. BTt-C and BTt-DC are calculated.

  In the next step S3, the balance time target value setting section 600 stores the calculated balance time target values BTt-C and BAT-DC in the storage section 800.

  In the next step S4, based on the current upper limit value Imax and the balance time target values BTt-C, BTt-DC, the coil current control unit 700 causes the balance time target values BTt-C, BTt-DC from the start of charge and the start of discharge. By this time, a coil current to be supplied to the primary coil LP for balancing the voltages of the plurality of storage batteries is calculated and set.

  In the next step S5, the coil current control unit 700 stores the set values of the coil current during charging and during discharging in the storage unit 800. When step S5 is executed, the flow ends.

  By the pre-cell balance process performed as described above, the battery pack 1 is theoretically in a state where the cell balance at the time of charge / discharge is obtained before the charge / discharge.

  Next, a power storage state adjustment process (also referred to as a cell balance process, hereinafter the same) by the cell balance control system of the first embodiment will be described with reference to a flowchart of FIG. This storage state adjustment process is performed when the battery pack 1 is charged and discharged after the pre-cell balance process. Specifically, the process is started by the coil current control unit 700 when the battery pack 1 is connected to a charger or a load. At this time, time measurement by the timer 900 is started. In addition, when the battery pack 1 is connected to the charger or the load or when the connection is released, a signal notifying the notification (a charger connection signal, a charger connection release signal, a load connection signal, a load connection release signal). Is transmitted from the charger / load connection detection unit 960 to the coil current control unit 700.

  In the first step S11, the coil current control section 700 determines whether or not it is connected to a charger. If the determination here is affirmed, the process proceeds to step S12, and if denied, the process proceeds to step S13.

  In step S12, a coil current is supplied. More specifically, the coil current control unit 700 sends a set value of the coil current amount during charging (a pulse signal having a pulse amplitude of the coil current value and a pulse width of the supply time) to the variable constant current circuit 400 at a predetermined time interval. (With a predetermined pulse period). At this time, the coil current amount of the set value is supplied from the variable constant current circuit 400 to the primary coil LP at predetermined time intervals. Each time the supply of the coil current is completed, the energy stored in the primary coil LP is transmitted to the secondary coil corresponding to at least one storage battery by the back electromotive energy, and the voltage difference between the storage batteries is reduced. When step S12 is performed, the process proceeds to step S14.

  In step S13, the coil current control unit 700 sends a set value of the coil current amount at the time of discharging (a pulse signal having a coil current value as a pulse amplitude and a supply time as a pulse width) to the variable constant current circuit 400 at predetermined time intervals. (With a predetermined pulse period). At this time, the coil current amount of the set value is supplied from the variable constant current circuit 400 to the primary coil LP. When the supply of the coil current is completed, the energy stored in the primary coil LP is transmitted to the secondary coil corresponding to at least one storage battery by the back electromotive energy, and the voltage difference between the storage batteries is reduced. When step S13 is performed, the process proceeds to step S15.

  In step S <b> 14, the coil current control unit 700 determines whether or not the balance time target value BTt-C during charging has elapsed by measuring the time of the timer 900. If the determination here is affirmed, the flow ends, and if denied, the process returns to step S12.

  In step S15, the coil current control unit 700 determines whether or not the balance time target value BTt-DC at the time of discharging has elapsed by measuring the time of the timer 900. If the determination here is affirmed, the flow ends, and if denied, the process returns to step S13.

  Next, a cell balance control system of Example 2 of the battery pack 1 of the first embodiment will be described with reference to FIG.

  By the way, the balance time target value is repeatedly updated by the pre-cell balance process. However, immediately after the update, the power storage state adjustment process is not necessarily performed. The remaining amount of the storage battery changes, and the total amount of coil current to be supplied to the primary coil LP changes in order to balance the cells while suppressing power loss.

  Therefore, in the cell balance control system according to the second embodiment, as shown in FIG. 10, a balance time target value correction unit 650 is provided.

  The balance time target value correction unit 650 acquires the differences ΔV1 to ΔV3 of the battery voltages of the plurality of storage batteries from the voltage monitoring unit 500 during charging / discharging (preferably at the beginning of charging), and obtains a balance value that is a correction value of the balance time target value. The time target value correction value BTt ′ is calculated and stored in the storage unit 800.

  Here, the balance time target value setting unit 600 stores the differences ΔV1 to ΔV3 of the battery voltages of the plurality of storage batteries in the storage unit 800 in addition to the balance time target value BTt during the pre-cell balance processing. That is, the balance time target value BTt and ΔV1 to ΔV3 are updated for each pull cell balance process.

  Then, the balance time target value correction unit 650 stores the balance time target values BTt-C and BTt-DC at the time of charging and discharging, and the sum (the former) of ΔV1 to ΔV3 at the start of charging and discharging in the storage unit 800. If the sum is larger (the latter) of ΔV1 to ΔV3 during the pre-cell balance process, the charge is increased by the ratio of the former and the latter, and if smaller, it is decreased by the ratio of the former and the latter. At this time, the correction value of the balance time target value at the time of discharging is stored in the storage unit 800. When the former and the latter substantially match (for example, when the difference between them is less than 3% of the average of both), the balance time target value is not corrected.

  Next, a power storage state adjustment process performed by the cell balance control system of Example 2 of the battery pack 1 of the first embodiment will be described with reference to the flowchart of FIG. This storage state adjustment process is performed at the start of charging and discharging of the battery pack 1 after the pre-cell balance process. Specifically, the process is started by the coil current control unit 700 when the battery pack 1 is connected to a charger or a load. At this time, time measurement by the timer 900 is started. In the following, for the sake of convenience, the power storage state adjustment processing during charging and discharging will be described collectively without distinction.

  In the first step S <b> 21, the balance time target value correction unit 650 calculates the sum of ΔV1 to ΔV3 during charging / discharging (preferably at the beginning of charging) and the sum of ΔV1 to ΔV3 during precell balance processing stored in the storage unit 800. Compare.

  In the next step S22, the balance time target value correction unit 650 determines whether the correction of the balance time target value is necessary as described above. If the determination here is affirmative, the process proceeds to step S23, and if negative, the process proceeds to step S24.

  In step S23, the balance time target value correction unit 650 calculates the balance time target value based on the ratio of the sum of ΔV1 to ΔV3 during charging to the sum of ΔV1 to ΔV3 during precell balance processing, and the coil current amount set value. to correct.

  In step S24, the coil current control section 700 supplies the coil current amount of the set value.

  In step S25, it is determined whether or not the balance time target value has elapsed by measuring the time of the timer 900. If the determination here is affirmed, the flow ends, and if denied, the process returns to step S24.

  Next, a cell balance control system according to a third embodiment of the first embodiment will be described with reference to FIG.

  By the way, the balance time target value and the coil current amount set value are repeatedly updated by the pre-cell balance processing. However, if the storage state adjustment processing is not performed immediately after the update, the storage state of the battery pack 100 from the time of the update. (The remaining amount of the plurality of storage batteries) changes, and the total amount of coil current to be supplied to the primary coil LP changes in order to balance the cells while suppressing power loss.

  Therefore, the cell balance control system according to the third embodiment includes a current sensor IS and a current monitoring unit 950, as shown in FIG.

  The current sensor IS is connected in series to the primary coil LP, and measures a current (coil current) flowing through the primary coil LP.

  The measurement value of the current sensor IS is sent to the current monitoring unit 950. The current monitoring unit 950 calculates a difference ΔI between the current value of the coil current amount set value stored in the storage unit 800 during the pre-cell balance process and the measurement value of the current sensor IS during charging / discharging (preferably at the beginning of charging), It is stored in the storage unit 800.

  The coil current control unit 700 calculates a coil current amount correction value based on the current upper limit value Imax, the balance time target value BTt, and the coil current amount set value stored in the storage unit 800, and stores the same in the storage unit 800. To correct the coil current amount setting value, the coil current setting value (pulse amplitude), the current supply time (pulse width), and the supply time interval (pulse cycle) At least one may be changed.

  Specifically, the coil current control unit 700 sets the coil current amount setting value to a value when the coil current amount during charging / discharging (the former) is larger than the coil current amount setting value during the pre-cell balance process (the latter). , The former is decreased by the ratio of the former, and the latter is increased by the ratio of the former and the latter, and the obtained coil current correction values at the time of charging and discharging are stored in the storage unit 800. When the former and the latter substantially match (for example, when the difference between them is less than 3% of the average of both), the coil current amount set value is not corrected.

  Next, the storage state adjustment processing by the cell balance control system of Example 3 of the battery pack 1 of the first embodiment will be described with reference to the flowchart of FIG. This storage state adjustment process is performed at the start of charging and discharging of the battery pack 1 after the pre-cell balance process. Specifically, the process is started by the coil current control unit 700 when the battery pack 1 is connected to a charger or a load. At this time, time measurement by the timer 900 is started. In the following, for the sake of convenience, the power storage state adjustment processing during charging and discharging will be described collectively without distinction.

  In the first step S31, the coil current control section 700 supplies the set coil current amount.

  In the next step S32, the current monitoring unit 950 acquires the measurement value of the current sensor IS.

  In the next step S33, the coil current control section 700 determines whether or not the coil current set value needs to be corrected as described above. If the determination here is affirmed, the process proceeds to step S34, and if negative, the process proceeds to step S36.

  In step S34, the coil current control unit 700 corrects the coil current amount set value based on the difference ΔI between the coil current set value during the pre-cell balance process and the measurement value of the current sensor IS during charging / discharging, and is obtained. The stored coil current correction value is stored in the storage unit 800.

  In the next step S35, the coil current control unit 700 supplies the coil current amount of the set value after the correction.

  In step S36, it is determined whether or not the balance time target value has elapsed by measuring the time of the timer 900. If the determination here is affirmed, the flow ends, and if the determination is denied, the same determination is performed again.

  In the cell balance control system of the third embodiment, the coil current amount is corrected based on the measurement value of the current sensor IS. However, as in the cell balance control system of the fourth embodiment shown in FIG. The set value of the coil current may be corrected based on the ratio of the sum of ΔV1 to ΔV3 during the cell balance process and the sum of ΔV1 to ΔV3 during charge and discharge.

  Further, in the cell balance control system according to the second embodiment, the balance time target value is corrected based on the measured values of the four voltage sensors. However, as in the cell balance control system according to the fifth embodiment illustrated in FIG. Alternatively, the balance time target value may be corrected based on the value ΔI obtained by subtracting the coil current set value (the latter) during pre-cell balance processing from the measurement value (the former) of the current sensor IS during charging / discharging. Specifically, when ΔI is positive and large, the balance time target value is decreased, and when ΔI is negative and large, the balance time target value is increased. When ΔI is approximately 0 (for example, when the absolute value of ΔI is If it is less than 3% of the average of the former and the latter), no correction is made.

  Hereinafter, the cell balance control system of Example 1 of the battery pack 2 of the second embodiment will be described with reference to FIG.

  As shown in FIG. 16, the cell balance control system of Example 1 of the second embodiment is provided with four variable constant current circuits 400A to 400D corresponding to the four primary coils LP1 to LP4. However, this is different from the cell balance control system of Example 1 of the first embodiment.

  Then, based on ΔV1 to ΔV3, the balance time target value BTt, and the current upper limit value Imax stored in the storage unit 800 in the pre-cell balance process, the coil current control unit 700 determines at least one of the four variable constant current circuits 400A to 400D. A coil current amount to be supplied to one is set, and the set value (coil current amount set value) is stored in the storage unit 800. Here, at the time of charging / discharging, the coil current amount set by the variable constant current circuit for the primary coil corresponding to the storage battery whose battery voltage is lower than the average value of the battery voltages of the four storage batteries in the pre-cell balance process is It is supplied until the balance time target value BTt has elapsed.

  Hereinafter, a cell balance control system of Example 2 of the battery pack 2 of the second embodiment will be described with reference to FIG.

  As shown in FIG. 17, the cell balance control system of Example 2 of the second embodiment is provided with four variable constant current circuits 400A to 400D corresponding to the four primary coils LP1 to LP4. However, this is different from the cell balance control system of Example 2 of the first embodiment.

  Then, based on ΔV1 to ΔV3, the balance time target value BTt, and the current upper limit value Imax stored in the storage unit 800 in the pre-cell balance process, the coil current control unit 700 determines at least one of the four variable constant current circuits 400A to 400D. A coil current amount to be supplied to one is set, and the set value (coil current amount set value) is stored in the storage unit 800. Here, at the time of charging and discharging, the balance time target value BTt is corrected as necessary, as in Example 2 of the first embodiment, and corresponds to a storage battery whose battery voltage is lower than the average value of the battery voltages of the four storage batteries. The primary coil is supplied from the variable constant current circuit until the set coil current amount exceeds the balance time target value.

  Hereinafter, a cell balance control system of Example 3 of the battery pack 2 of the second embodiment will be described with reference to FIG.

  As shown in FIG. 18, the cell balance control system of Example 3 of the second embodiment includes four variable constant current circuits 400A to 400D corresponding to four primary coils LP1 to LP4 and four current sensors IS1. IS4 is different from the cell balance control system of Example 3 of the first embodiment.

  Then, based on ΔV1 to ΔV3, the balance time target value BTt, and the current upper limit value Imax stored in the storage unit 800 in the pre-cell balance process, the coil current control unit 700 determines at least one of the four variable constant current circuits 400A to 400D. A coil current amount to be supplied to one is set, and the set value (coil current amount set value) is stored in the storage unit 800. Here, at the time of charge / discharge, the balance time target value BTt is corrected as needed, as in Example 3 of the first embodiment, and the battery voltage corresponds to a storage battery whose battery voltage is lower than the average value of the battery voltages of the four storage batteries. The primary coil is supplied from the variable constant current circuit until the set coil current amount exceeds the balance time target value.

  Hereinafter, a cell balance control system of Example 4 of the battery pack 2 of the second embodiment will be described with reference to FIG.

  As shown in FIG. 19, the cell balance control system of Example 4 of the second embodiment is provided with four variable constant current circuits 400A to 400D corresponding to the four primary coils LP1 to LP4. However, this is different from the cell balance control system of Example 4 of the first embodiment.

  Then, based on ΔV1 to ΔV3, the balance time target value BTt, and the current upper limit value Imax stored in the storage unit 800 in the pre-cell balance process, the coil current control unit 700 determines at least one of the four variable constant current circuits 400A to 400D. A coil current amount to be supplied to one is set, and the set value (coil current amount set value) is stored in the storage unit 800. Here, at the time of charging and discharging, the set value of the coil current amount is corrected as necessary in the same manner as in Example 4 of the first embodiment, and the battery voltage corresponds to a storage battery whose battery voltage is lower than the average value of the battery voltages of the four storage batteries. The primary coil is supplied from the variable constant current circuit until the set coil current amount exceeds the balance time target value.

  Hereinafter, a cell balance control system of Example 5 of the battery pack 2 of the second embodiment will be described with reference to FIG.

  As shown in FIG. 20, the cell balance control system of Example 5 of the second embodiment includes four variable constant current circuits 400A to 400D corresponding to four primary coils LP1 to LP4 and four current sensors IS1. IS4 is different from the cell balance control system of Example 5 of the first embodiment.

  Then, based on ΔV1 to ΔV3, the balance time target value BTt, and the current upper limit value Imax stored in the storage unit 800 in the pre-cell balance process, the coil current control unit 700 determines at least one of the four variable constant current circuits 400A to 400D. A coil current amount to be supplied to one is set, and the set value (coil current amount set value) is stored in the storage unit 800. Here, at the time of charging and discharging, the balance time target value is corrected as necessary, as in Example 5 of the first embodiment, and the primary voltage corresponding to the storage battery whose battery voltage is lower than the average value of the battery voltages of the four storage batteries is corrected. The coil current amount set from the variable constant current circuit is supplied to the side coil until the balance time target value has passed.

  The storage state adjustment devices of the first and second embodiments described above are storage state adjustment devices that adjust the storage state of a battery pack 100 in which a plurality (for example, four) of storage batteries BAT1 to BAT4 are connected in series. A primary coil connected in series with the plurality of storage batteries, a plurality of secondary coils connected in parallel with each of the plurality of storage batteries, and to which energy stored in the primary coil is transmitted, and charging the battery pack 100 A target value of a balance time (balance time target value), which is a time from the start or the start of discharge until the voltages of a plurality of storage batteries are balanced, is set, and based on the target value, the total energy amount stored in the primary coil And a cell balance control system that adjusts

  In this case, by setting the balance time target value to an appropriate value, it is possible to reduce (preferably minimize) the total amount of energy stored in the primary coil for cell balancing during charging and discharging.

  As a result, it is possible to suppress an increase in the amount of energy loss (the amount of power loss), which is a value obtained by subtracting the amount of energy actually consumed for cell balancing from the total amount of energy stored in the primary coil.

  As a result, an increase in power loss (energy loss) during charging and discharging can be suppressed.

  In short, in the first and second embodiments, setting the balance time target value is equivalent to the total energy amount (coil current amount × the number of supply times (number of pulses)) accumulated in the primary side coil for cell balancing. It is nothing but setting the amount of energy loss. That is, since the amount of energy loss changes depending on the setting of the balance time target value, it is very important to appropriately set the balance time target value.

  That is, under the same condition of the charging time or the discharging time, by appropriately setting the balance time target value, it is possible to minimize the power loss at the time of charging and discharging.

  In addition, since it is not necessary to take a circuit configuration for increasing the amount of energy stored in the primary coil, it is possible to suppress an increase in the size of the device.

  Further, the cell balance control system controls the balance time so that the total amount of energy stored in the primary coil is equal to or less than a predetermined value within a range of a preset charging time CT or discharging time DCT for the battery pack 100. It is preferable to set a target value and adjust the total energy amount to be equal to or less than a predetermined value.

  In this case, the balance time target value can be set to an appropriate value.

  In addition, the cell balance control system may set a balance time target value and set the total energy amount stored in the primary coil based on the balance time target value at times other than charging and discharging of the battery pack 100. preferable.

  In this case, a cell balance can be obtained in advance. As a result, at the time of charge / discharge, the set total energy amount may be supplied to the primary coil from the start of charge or the start of discharge to the set balance time target value, so that control during charge / discharge is simplified. it can.

  In addition, the power storage state adjusting device further includes a plurality of (for example, four) voltage sensors VS1 to VS4 for measuring the voltages of the plurality of storage batteries, and the cell balance control system includes a balance time target value and outputs of the plurality of voltage sensors. It is preferable to adjust the total amount of energy stored in the primary coil based on the following equation.

  In this case, the total energy amount can be adjusted according to the difference between the balance time target value and the voltages of the plurality of storage batteries at the time of charging and discharging, so that the cell balance can be accurately performed.

  Further, it is preferable that the cell balance control system can change the setting of the balance time target value according to the measurement values of the plurality of voltage sensors.

  In this case, since the setting of the balance time target value can be changed in accordance with the storage state of the storage battery, even if the storage state of the storage battery changes after the balance time target value is set, the total energy amount corresponding to the change is primarily calculated. Can be supplied to the side coil.

  Further, the power storage state adjusting device further includes a current sensor for measuring a current supplied to the primary coil, and the cell balance control system is stored in the primary coil based on a balance time target value and a measurement value of the current sensor. It is preferable to adjust the total energy amount.

  In this case, since the total energy amount can be adjusted according to the balance time target value and the current supplied to the primary side coil at the time of charging / discharging, the cell balance can be accurately performed.

  In the second embodiment, a plurality of primary coils are provided corresponding to the plurality of secondary coils, and a plurality of current sensors are provided corresponding to the plurality of primary coils.

  In this case, since the current supplied to the plurality of primary coils can be individually measured, the current supplied to the plurality of primary coils can be individually adjusted according to the measured value.

  Further, it is preferable that the cell balance control system can change the setting of the balance time target value according to the measurement value of the current sensor.

  In this case, since the setting of the balance time target value can be changed in accordance with the storage state of the storage battery, even if the storage state of the storage battery changes after the balance time target value is set, the total energy amount corresponding to the change is primarily calculated. Can be supplied to the side coil.

  Preferably, the cell balance control system includes a variable constant current circuit connected to the primary coil.

  In this case, the current can be stably supplied to the primary coil, and the current value of the current can be changed as needed.

  In the second embodiment, a plurality of primary coils are provided corresponding to the plurality of secondary coils, and a plurality of variable constant current circuits are provided corresponding to the plurality of primary coils.

  In this case, the current can be individually and stably supplied to the plurality of primary-side coils, and the current value of the current can be changed as needed.

  The battery packs 1 and 2 of the first and second embodiments each include an assembled battery 100 in which a plurality of storage batteries are connected in series, and a storage state adjustment device that adjusts the storage state of the assembled battery 100. I have.

  In this case, a battery pack having excellent charge / discharge efficiency can be provided.

  According to the load system including the battery pack of the first or second embodiment, the charger connected to the battery pack, and the load connected to the battery pack, the energy efficiency of the entire system is improved. can do.

  The power storage state adjustment methods of the first and second embodiments are power storage state adjustment methods for adjusting the power storage state of a battery pack 100 in which a plurality (for example, four) of storage batteries BAT1 to BAT4 are connected in series. A primary coil is connected in series to a plurality of storage batteries, and a plurality of secondary coils to which energy stored in the primary coil is transmitted are connected in parallel to each of the plurality of storage batteries. Setting a target value (balance time target value) of a balance time which is a time from the start of charging or the start of discharging to the time when the voltages of the plurality of storage batteries are balanced; and storing the target value in the primary coil based on the target value. Adjusting the amount of energy.

  In this case, by setting the target balance time to an appropriate value, the total amount of energy stored in the primary coil can be reduced.

  As a result, an increase in power loss (energy loss) during charging and discharging can be suppressed.

  Further, in the setting step, the balance time target is set so that the total amount of energy stored in the primary coil is equal to or less than a predetermined value within the range of the charging time CT or the discharging time DCT preset for the battery pack 100. In the step of setting and adjusting the value, it is preferable to adjust the energy amount to be equal to or less than a predetermined value.

  In this case, the balance time target value can be set to an appropriate value.

  In the setting step, the balance time target value is set when the battery pack 100 is not charged and discharged, and in the adjusting step, the total time is set based on the balance time target value when the battery pack 100 is not charged and discharged. It is preferable to set the amount of energy.

  In this case, a cell balance can be obtained in advance. As a result, at the time of charge / discharge, the set total energy amount may be supplied to the primary coil from the start of charge or the start of discharge to the set balance time target value, so that control during charge / discharge is simplified. it can.

  In each of the above embodiments, a variable constant current circuit is provided as an adjustment unit for adjusting the coil current. However, the present invention is not limited to this. For example, a constant current source and a resistance circuit that can switch the resistance value are provided. Or a circuit including a variable resistor, or a switching transistor for repeating connection and disconnection between the primary coil and the assembled battery may be provided.

  Further, the configuration of the variable constant current circuit is not limited to the configuration of the variable constant current circuits 400 and 400A to 400D, and can be appropriately changed.

  In the above-described embodiment, a flyback transformer is used as the current supply circuit. However, the present invention is not limited to this, and another current adder may be used. Also in this case, it is preferable that the cell balance control system controls the current adder as the current supply circuit based on the balance time target value.

  Further, in the above embodiment, the numbers of storage batteries, primary coils, secondary coils, voltage sensors, and current sensors constituting the battery pack can be changed as appropriate.

  Further, in the above embodiment, the balance time target value is set at the time of the pre-cell balance processing. However, instead of or in addition to this, the balance time target value may be set, for example, during charging / discharging or reset as needed.

  Further, in the above embodiment, the total amount of energy stored in the primary coil based on the balance time target value = the coil current value (pulse amplitude) × the supply time (pulse width) × the number of supply times (the number of pulses) is controlled. However, the present invention is not limited to this, and the coil current value, the coil current amount (coil current value × supply time) and the number of times of supply may be controlled while keeping the total energy amount stored in the primary coil constant. Also in this case, an increase in power loss can be suppressed by suppressing the coil current value, the coil current amount, and the number of times of supply from the start of charging or the start of discharging to the target value of the balance time below the threshold. That is, by dispersing the current value, the current amount, and the supply time with time, the current value and the current amount can be controlled to be small (preferably minimum), and an increase in energy loss and an increase in size of the device can be suppressed.

  Further, specific numerical values, shapes, and the like used in the description of the above embodiment can be appropriately changed without departing from the spirit of the present invention.

  Hereinafter, a thinking process that led the inventor to devise the above-described embodiment will be described.

  Patent Literature 1 discloses a cell balancing method in which a charging current is adjusted in order to make cell voltages of a plurality of storage batteries connected in series in a power storage module the same during charging.

  However, at the time of high-speed charge / discharge, power loss increases and the module becomes large.

  Therefore, the inventor has devised the above-described embodiment in order to suppress an increase in energy loss and an increase in the size of the device during cell balancing when a plurality of storage batteries are charged and discharged at high speed.

  1, 2 battery pack, 100 battery pack, 400 variable constant current circuit, 600 balance time target value setting section, 700 coil current control section, 800 storage section, V1 to V4 voltage sensors, IS, IS1 ~ IS4 ... current sensor.

JP 2015-154606 A

Claims (14)

A storage state adjustment device that adjusts the storage state of a battery pack in which a plurality of storage batteries are connected in series,
A current supply circuit that supplies a current for balancing the voltages of the plurality of storage batteries to the battery pack during charging and discharging of the battery pack,
A control system that sets a target value of a balance time that is a time period from the start of charging or the start of discharging of the battery pack to the time when the voltages of the plurality of storage batteries are balanced, and controls the current supply circuit based on the target value. ,
The current supply circuit includes a primary coil connected in series to the plurality of storage batteries, and a plurality of secondary sides connected in parallel to each of the plurality of storage batteries and to which energy stored in the primary coil is transmitted. And a coil,
The power storage state adjusting device, wherein the control system sets the target value and sets the total amount of energy stored in the primary coil based on the target value when the battery pack is not charged or discharged.   The power storage condition adjusting device according to claim 1, wherein the target value substantially matches a charging time or a discharging time preset for the battery pack. A storage state adjustment device that adjusts the storage state of a battery pack in which a plurality of storage batteries are connected in series,
A current supply circuit that supplies a current for balancing the voltages of the plurality of storage batteries to the battery pack during charging and discharging of the battery pack,
A control system that sets a target value of a balance time that is a time period from the start of charging or the start of discharging of the battery pack to the time when the voltages of the plurality of storage batteries are balanced, and controls the current supply circuit based on the target value. ,
A plurality of voltage sensors for measuring the voltage of each of the plurality of storage batteries,
The current supply circuit includes a primary coil connected in series to the plurality of storage batteries, and a plurality of secondary sides connected in parallel to each of the plurality of storage batteries and to which energy stored in the primary coil is transmitted. And a coil,
The power storage state adjustment device, wherein the control system is capable of adjusting a total amount of energy stored in the primary coil based on the target value and the measurement values of the plurality of voltage sensors.   4. The power storage state adjustment device according to claim 3, wherein the control system is capable of changing a setting of the target value according to a measurement value of the plurality of voltage sensors. 5. A storage state adjustment device that adjusts the storage state of a battery pack in which a plurality of storage batteries are connected in series,
A current supply circuit that supplies a current for balancing the voltages of the plurality of storage batteries to the battery pack during charging and discharging of the battery pack,
A control system that sets a target value of a balance time that is a time period from the start of charging or the start of discharging of the battery pack to the time when the voltages of the plurality of storage batteries are balanced, and controls the current supply circuit based on the target value. ,
The current supply circuit includes a primary coil connected in series to the plurality of storage batteries, and a plurality of secondary sides connected in parallel to each of the plurality of storage batteries and to which energy stored in the primary coil is transmitted. And a coil,
Further comprising a current sensor that measures a current supplied to the primary side coil,
The power storage state adjustment device, wherein the control system is capable of adjusting a total amount of energy stored in the primary coil based on the target value and a measurement value of the current sensor. The primary coil is provided in plurality corresponding to the plurality of secondary coils,
The storage state adjusting device according to claim 5, wherein a plurality of the current sensors are provided corresponding to the plurality of primary coils.   The power storage state adjusting device according to claim 5, wherein the control system is capable of changing a setting of the target value according to a measurement value of the current sensor.   The power storage state adjustment device according to any one of claims 1 to 7, wherein the control system includes a variable constant current circuit connected to the primary coil.   The power storage state adjusting device according to claim 8, wherein a plurality of the variable constant current circuits are provided corresponding to the plurality of primary coils. An assembled battery in which a plurality of storage batteries are connected in series;
A battery pack comprising: the power storage state adjusting device according to claim 1, wherein the power storage state of the battery pack is adjusted. A battery pack according to claim 10,
A charger connected to the battery pack;
A load connected to the battery pack. A storage state adjustment method for adjusting the storage state of a battery pack in which a plurality of storage batteries are connected in series,
Current for balancing the voltages of the plurality of storage batteries during charging and discharging of the battery pack is supplied to the battery pack from a current supply circuit,
The current supply circuit includes a primary coil connected in series to the plurality of storage batteries, and a plurality of secondary sides connected in parallel to each of the plurality of storage batteries and to which energy stored in the primary coil is transmitted. And a coil,
A step of setting a target value of a balance time that is a time from the start of charging or the start of discharging of the battery pack to the time when the voltages of the plurality of storage batteries are balanced,
Controlling the current supply circuit based on the target value,
In the setting step, the target value is set at times other than at the time of charging and discharging the battery pack,
In the controlling step, a power storage state adjusting method for setting a total amount of energy stored in the primary coil based on the target value except when the battery pack is charged or discharged. A storage state adjustment method for adjusting the storage state of a battery pack in which a plurality of storage batteries are connected in series,
Current for balancing the voltages of the plurality of storage batteries during charging and discharging of the battery pack is supplied to the battery pack from a current supply circuit,
The current supply circuit includes a primary coil connected in series to the plurality of storage batteries, and a plurality of secondary sides connected in parallel to each of the plurality of storage batteries and to which energy stored in the primary coil is transmitted. And a coil,
A step of setting a target value of a balance time that is a time from the start of charging or the start of discharging of the battery pack to the time when the voltages of the plurality of storage batteries are balanced,
Controlling the current supply circuit based on the target value,
In the controlling step, a storage state adjustment method capable of adjusting a total amount of energy stored in the primary coil based on measurement values of a plurality of voltage sensors for measuring voltages of the plurality of storage batteries and the target value. . A storage state adjustment method for adjusting the storage state of a battery pack in which a plurality of storage batteries are connected in series,
Current for balancing the voltages of the plurality of storage batteries during charging and discharging of the battery pack is supplied to the battery pack from a current supply circuit,
The current supply circuit includes a primary coil connected in series to the plurality of storage batteries, and a plurality of secondary sides connected in parallel to each of the plurality of storage batteries and to which energy stored in the primary coil is transmitted. And a coil,
A step of setting a target value of a balance time that is a time from the start of charging or the start of discharging of the battery pack to the time when the voltages of the plurality of storage batteries are balanced,
Controlling the current supply circuit based on the target value,
In the controlling step, a power storage state adjustment method capable of adjusting a total energy amount stored in the primary coil based on a measurement value of a current sensor that measures a current supplied to the primary coil and the target value. .

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