JP5953567B2 - Power storage device and charging / discharging method thereof - Google Patents

Description

  The present invention relates to a power storage device and a charge / discharge method thereof, and is particularly useful when applied to a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series.

  When charging or discharging a battery cell unit configured by connecting a plurality of battery cells in series, it is necessary to control the battery cell so that overcharge or overdischarge does not occur. This is because overcharging and overdischarging of the battery cell cause deterioration of the battery cell itself. As a technique for suppressing the occurrence of overdischarge and overcharge, in the case of a battery cell unit, in order to suppress the occurrence of variations between battery cells due to charging, the charge state is equalized between the battery cells. It is known to perform so-called balance adjustment. Examples of techniques for adjusting the balance include those described in Patent Documents 1 to 4.

JP 11-285162 A JP 07-336905 A JP 2007-318950 A Japanese Patent Laid-Open No. 05-064377

  In Patent Document 1 and Patent Document 3, the charging current of the secondary battery cell that has reached a control start voltage lower than the target voltage for full charge is reduced, and charging is performed until all the secondary battery cells reach the target voltage for full charge. However, since the charging current is reduced from the control start voltage to the fully charged target voltage, charging takes time if the voltage value difference is large, and some The secondary battery cells reach the target voltage for full charge early, while the other secondary battery cells continue to be charged with a small charge current. There is a possibility that the secondary battery cell may be overcharged.

  In Patent Document 2, the charging current is bypassed so that the terminal voltage is kept constant by the terminal voltage control unit for each of the plurality of single cells constituting the assembled battery, and when the bypass current is saturated, the charging current to the assembled battery is decreased. Therefore, complicated control is required such as constantly controlling the terminal voltage so as to keep the terminal voltage constant, or performing control to detect the saturation of the bypass current and reduce the charging current. In addition, the charging current value is lowered as it goes to full charge, and the charge current value becomes smaller near full charge, so there is a concern that it takes time to charge near full charge.

  Patent Document 4 merely discloses bypassing a charging current for a fully charged battery cell, and reduces the charging current to a battery cell that has been determined to be fully charged before all the battery cells are fully charged. Charging is continued, and if the time until the other battery cells are fully charged is long, there is a risk of overdischarge to the battery cells that have been determined to be fully charged.

  In any of the documents, there is only a description about the balance adjustment at the time of charging, and the balance adjustment at the time of discharging is not particularly described.

  In view of the above problems, the present invention provides a power storage device that can reliably prevent overcharging and overdischarging of battery cells, and can quickly realize equalization of the state of charge between battery cells, and a method for charging and discharging the same. The purpose is to do.

  A first aspect of the present invention that achieves the above object is provided with a battery cell unit configured by connecting a plurality of battery cells in series and corresponding to the plurality of battery cells, and flows to each of the battery cells. Current control means for independently controlling the charge / discharge current, and control means for controlling the charge / discharge current flowing in each battery cell via the current control means based on the cell voltage of each battery cell, and The control means has a full charge detection voltage, a charge control start voltage lower than the full charge detection voltage, a discharge lower limit detection voltage, and a discharge control start voltage higher than the discharge lower limit detection voltage as parameters, and during charging operation When any of the cell voltages reaches the charge control start voltage, the current control means is set to the first state to supply the battery cell that has reached the charge control start voltage. The charging current is reduced, and when the cell voltage of all the battery cells reaches the charging control start voltage, charging is performed by increasing the reduced charging current again by setting the current control means to the second state. When the cell voltage of any battery cell reaches the full charge detection voltage, the charging operation is terminated. On the other hand, when any cell voltage reaches the discharge control start voltage during the discharge operation, the current control means causes the discharge. The discharge current discharged from the battery cell that has not reached the control start voltage is increased, and after all the battery cells have reached the discharge control start voltage, any one of the battery cells The power storage device is configured to terminate the discharge operation when the cell voltage reaches the discharge lower limit detection voltage.

  According to this aspect, in the charging operation, two threshold voltages (charging control start voltage, full charge detection voltage) are provided to control charging in two stages. While removing the possibility, it can be performed in a short time, and at the same time, in the discharge operation, the other two threshold voltages (discharge control start voltage, discharge lower limit detection voltage) are provided to control the discharge in two stages. Therefore, it is possible to appropriately perform the operation from the start to the end of the discharge control while eliminating the possibility of overdischarge or the like. In addition, when charging, when all the battery cells reach the charge control start voltage, the charge current reduced by the current control means is increased, so that overcharge and the like are reduced and charging operation is performed in a short time appropriately. Can be realized.

According to a second aspect of the present invention, a battery cell unit configured by connecting a plurality of battery cells in series and a charge current flowing through each of the battery cells is provided independently of the plurality of battery cells. Current control means for controlling the battery cell, and control means for controlling the charging current flowing through each battery cell via the current control means based on the cell voltage of each battery cell. A voltage and a charge control start voltage lower than the full charge detection voltage are set as parameters, and when any of the cell voltages reaches the charge control start voltage during the charge operation, the current control means is set to the first with continued charging while reducing the charging current supplied for the battery cell reaches the charge control starting voltage by the state, the cell voltages of all the battery cells When the power control start voltage is reached, the current control means is set to the second state to charge the reduced charge current again, and charging is performed when the cell voltage of any battery cell reaches the full charge detection voltage. The power storage device is configured to terminate the operation.

  According to this aspect, since the charging operation is controlled in two stages by providing two threshold voltages (charging control start voltage, full charge detection voltage), the charging operation can be overcharged. It can be performed in a short time appropriately while removing. In particular, when all the battery cells reach the charging control start voltage, the charging current reduced by the current control means is increased, so that it is possible to appropriately perform a charging operation in a short time while reducing overcharging.

  According to a third aspect of the present invention, a battery cell unit configured by connecting a plurality of battery cells in series and a discharge current flowing through each of the battery cells is provided independently of the plurality of battery cells. Current control means for controlling the discharge current, and control means for controlling the discharge current flowing to each battery cell via the current control means based on the cell voltage of each battery cell. The discharge control start voltage higher than the voltage and the discharge lower limit detection voltage is set as a parameter, and when any cell voltage reaches the discharge control start voltage during the discharge operation, the current control means is controlled. The discharge current discharged from the battery cells that have not reached the discharge control start voltage is increased, and the cell voltages of all the battery cells are discharged. Even after reaching the voltage, in the power storage device cell voltage of one of the battery cells is characterized in that it is configured to terminate reaches the discharge operation in the discharge lower limit detection voltage.

  According to this aspect, since the discharge operation is controlled in two stages by providing the other two threshold voltages (discharge control start voltage, discharge lower limit detection voltage), it is possible to overdischarge the discharge operation. The operation from the start to the end of the discharge control can be appropriately performed while removing.

  According to a fourth aspect of the present invention, in the power storage device according to any one of the first to third aspects, each of the current control units includes a configuration in which an impedance element and a switch unit are connected in series. The control means comprises a plurality of bypass circuits respectively connected in parallel to the battery cells, and the control means opens and closes each switch means based on the monitoring results of the plurality of voltage monitoring circuits each monitoring the cell voltage of each battery cell. The power storage device is characterized by being controlled.

  According to this aspect, it can control easily and appropriately by bypassing the current of the corresponding battery cell.

  According to a fifth aspect of the present invention, there is provided a charging / discharging method for a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series, and at the time of charging, any one of the cell voltages is fully charged. When the charging control start voltage set in advance as a voltage lower than the full charge detection voltage representing that is reached, the charging current provided corresponding to each battery cell and flowing through each battery cell is independently controlled. By setting the current control means to be in the first state, the charging current supplied to the battery cell that has reached the charge control start voltage is reduced, and the cell voltages of all the battery cells are changed to the charge control start voltage. When the current control means reaches the second state, charging is performed by increasing again the charging current that has been reduced by setting the current control means to the second state, and the cell voltage of any battery cell is greater than the charging control start voltage. When a high full charge detection voltage is reached, the charging operation is terminated, and at the time of discharge, a discharge control start voltage set in advance as a voltage higher than a discharge lower limit detection voltage indicating that any of the cell voltages is a discharge lower limit voltage. The discharge discharged from the battery cells not corresponding to the discharge control start voltage by the current control means that is provided corresponding to each of the battery cells and independently controls the discharge current flowing through each of the battery cells. The current is increased, and after the cell voltages of all the battery cells have reached the discharge control start voltage, the discharge occurs when the cell voltage of any of the battery cells reaches the discharge lower limit detection voltage. The power storage device charging / discharging method is characterized by terminating the operation.

  According to this aspect, in the charging operation, two threshold voltages (charging control start voltage, full charge detection voltage) are provided and charging is controlled in two stages. Therefore, the charging operation may be overcharged. In the discharge operation, the other two threshold voltages (discharge control start voltage and discharge lower limit detection voltage) are provided to control the discharge in two stages. Therefore, the operation from the start to the end of the discharge control can be appropriately performed while eliminating the possibility of overdischarge or the like. In addition, when charging, when all the battery cells reach the charge control start voltage, the charge current reduced by the current control means is increased, so that overcharge and the like are reduced and charging operation is performed in a short time appropriately. Can be realized.

A sixth aspect of the present invention is a method of charging a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series, wherein any one of the cell voltages is higher than a full charge detection voltage. When the charging control start voltage preset as a low voltage is reached, the current control means provided in correspondence with each battery cell and independently controlling the charging current flowing through each battery cell is set to the first state. Thus , charging is continued in a state where the charging current supplied to the battery cell that has reached the charge control start voltage is reduced, and the current control means is switched on when the cell voltages of all the battery cells reach the charge control start voltage. The charging current which has been reduced by changing to the state of 2 is increased again to perform charging, and the cell voltage of any battery cell is set to a full charge detection voltage higher than the charging control start voltage. Then in the charging method of the power storage device, characterized in that to terminate the charging operation.

  According to this aspect, since the charging operation is controlled in two stages by providing two threshold voltages (charging control start voltage, full charge detection voltage), the overcharging operation may be overcharged. It can be performed in a short time appropriately while removing. In particular, when all the battery cells reach the charging control start voltage, the charging current reduced by the current control means is increased, so that it is possible to appropriately perform a charging operation in a short time while reducing overcharging.

  A seventh aspect of the present invention is a method of discharging a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series, wherein any one of the cell voltages is higher than a discharge lower limit detection voltage. When the discharge control start voltage preset as a high voltage is reached, the discharge control start voltage is set to the discharge control start voltage by current control means provided in correspondence with each battery cell and independently controlling the discharge current flowing through each battery cell. The discharge current discharged from the battery cell that has not reached is increased, and after the cell voltages of all the battery cells have reached the discharge control start voltage, the cell voltage of any of the battery cells In the method for discharging a power storage device, the discharge operation is terminated when the discharge lower limit detection voltage is reached.

  According to this aspect, since the discharge operation is controlled in two stages by providing the other two threshold voltages (discharge control start voltage, discharge lower limit detection voltage), it is possible to overdischarge the discharge operation. The operation from the start to the end of the discharge control can be appropriately performed while removing.

  According to the present invention, the battery cell unit is set for each threshold value by setting two threshold levels at the time of charging or discharging, that is, a charge control start voltage and a full charge detection voltage and / or a discharge control start voltage and a discharge lower limit detection voltage. The charging current and / or discharging current of each battery cell constituting the can be controlled. As a result, appropriate control is performed so that overcharge and overdischarge do not occur without complicated control, and charge / discharge states between battery cells can be equalized more quickly. Can be executed.

It is a block diagram which shows the electrical storage apparatus which concerns on embodiment of this invention. 3 is an operation flowchart illustrating a charging operation in the power storage device illustrated in FIG. 1. 3 is an operation flowchart showing a discharging operation in the power storage device shown in FIG. 1.

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

  FIG. 1 is a block diagram showing a power storage device according to an embodiment of the present invention. As shown in the figure, the power storage device I includes a plurality of battery cells 10A to 10E connected in series (a plurality (five in this embodiment) of battery cells 10A to 10E are collectively referred to as a battery cell unit 10), Each of a plurality of bypasses each having one of impedance elements 20A to 20E and one of switches 30A to 30E connected in series and connected in parallel to a corresponding one of battery cells 10A to 10E of battery cell unit 10 The current control means constituted by a circuit, and the cell voltage of each of the battery cells 10A to 10E, which rises with the progress of charging and decreases with the progress of discharging, are monitored. The switches 30A to 30E are controlled to open and close based on the voltage, the charge control start voltage, the discharge control start voltage, or the discharge lower limit detection voltage, respectively. And a control unit 1 for controlling the charging and discharging operation of the cell unit 10.

  Here, at the time of charging the battery cell unit 10, the control means 1 switches 30A to 30E for the battery cells that reach the charge control start voltage whose cell voltage is lower than the full charge detection voltage among the battery cells 10A to 10E. By closing the corresponding switch among them, the bypass circuit is operated to reduce the amount of charging current supplied to the corresponding battery cell among the battery cells 10A to 10E. When the cell voltages of all the battery cells 10A to 10E reach the charge control start voltage, the operation of the bypass circuit is stopped by opening all the switches 30A to 30E, and the reduced charge current is increased again and charged. To do. Thus, when the cell voltage of any of the battery cells 10A to 10E reaches the full charge detection voltage, the charging is terminated. The charging current at this time is supplied from the charging power source 100.

  On the other hand, at the time of discharging from the battery cell unit 10, when any one of the battery cells 10A to 10E reaches the discharge control start voltage whose cell voltage is higher than the discharge lower limit detection voltage, the discharge control start voltage is reached among the battery cells 10A to 10E. With respect to the battery cell, the corresponding one of the switches 30A to 30E is opened, and the switches of the other battery cells are closed, thereby operating the bypass circuit of the battery cells 10A to 10E and starting discharge control. Increasing the amount of discharge current from battery cells that have not reached voltage. When the cell voltages of all the battery cells 10A to 10E reach the discharge control starting voltage, all the battery cells 10A to 10E are discharged by stopping the operation of the bypass circuit by opening all the switches 30A to 30E. Make it. Thus, the discharge is terminated when the cell voltage of any of the battery cells 10A to 10E reaches the discharge lower limit detection voltage. The discharge current at this time is supplied to the load 110.

  The control means 1 in the present embodiment for performing such a series of control, particularly control of the switches 30A to 30E, includes the voltage monitoring circuits 40A, 40B, 40C, 40D, 40E, the storage circuit 50, the storage circuit 60, the coincidence detection circuit 70, and the control device. 80, a charge / discharge end detection circuit 90 and switch control circuits 95A, 95B, 95C, 95D, and 95E. Here, the voltage monitoring circuits 40A to 40E monitor the cell voltages of the battery cells 10A to 10E, which rise as charging progresses and decrease as discharging progresses, and open and close the switches 30A to 30E according to the monitoring results. Outputs a control signal. The storage circuit 50 stores data corresponding to the set voltage used for comparison with the cell voltage in the voltage monitoring circuits 40A to 40E. The storage circuit 60 stores data to be stored in the storage circuit 50 and outputs a predetermined data based on an output instruction from the control device 80, such as a RAM (Random Access Memory) or a ROM (Read Only Memory). Etc. The coincidence detection circuit 70 is an AND gate that inputs the output signals of the voltage monitoring circuits 40A to 40E. The charge / discharge end detection circuit 90 is an OR gate for inputting the output signals of the voltage monitoring circuits 40A to 40E. The control device 80 receives the output of the coincidence detection circuit 70, and sends an output instruction signal for outputting data to be stored in the storage circuit 50 to the storage circuit 60 based on the output and the like, and at the same time, the charge / discharge end detection circuit 90. In response to this output, control such as termination processing of charging and discharging is performed. Each of the switch control circuits 95A to 95E outputs a signal for performing opening / closing control for a corresponding one of the switches 30A to 30E in response to a control signal from the control device 80.

  Specific control during the charging / discharging operation of the control means 1 is performed in a manner as shown in FIGS. FIG. 2 is an operation flowchart for explaining the charging operation, and FIG. 3 is an operation flowchart for explaining the discharging operation. Further, at the time of charging, a charging current is supplied from the charging power source 100 to the battery cell unit 10, and at the time of starting charging, all the switches 30A to 30E are in an open state (also referred to as an off state). On the other hand, at the time of discharging, a discharge current is supplied from the battery cell unit 10 to the load 110, and at the start of discharging, all the switches 30A to 30E are in an open state (also referred to as an off state).

<Control during charging operation>
1) The control device 80 has an arbitrary condition such as a charge instruction from an operation unit (not shown) or a state of charge (SOC) of the battery cells 10A to 10E reaching a set lower limit (for example, SOC is 30% or less). The charging process is started by recognizing that the power storage device I is in a charged state by the automatic process at the time when the charging is satisfied (see S101). At this time, the control device 80 generates an output instruction signal for reading out the data corresponding to the set voltage used for monitoring the cell voltage during charging from the storage circuit 60 and outputting it. The set voltage at the time of charging includes a full charge detection voltage for detecting the full charge and a charge control start voltage lower than the full charge detection voltage. Here, the storage circuit 60 stores data corresponding to the full charge detection voltage value and the charge control start voltage value. At the time of charging, data corresponding to the charging control start voltage value is first read out from the storage circuit 60 and output by the output instruction signal from the control device 80, so that the data corresponding to the charging control start voltage value is stored in the storage circuit. 50.

  2) The data stored in the storage circuit 50 is sent to the voltage monitoring circuits 40A to 40E (see S102).

  3) The voltage monitoring circuits 40A to 40E perform measurement for monitoring the cell voltages of the target battery cells 10A to 10E, respectively (see S103).

  4) The voltage monitoring circuits 40A to 40E compare the measured cell voltage with data corresponding to the charge control start voltage value sent from the storage circuit 50 as digital data. As a result of the comparison, each of the voltage monitoring circuits 40A to 40E outputs a signal representing a determination result of whether any of the battery cells 10A to 10E monitored by the voltage monitoring circuits 40A to 40E has reached the charging control start voltage (see S104). . For example, when the voltage monitoring circuit 40C determines that the cell voltage of the battery cell 10C to be monitored has reached the charge control start voltage, the voltage monitoring circuit 40C outputs a high level (5V level) signal, for example. The other voltage monitoring circuits 40A, 40B, 40D, and 40E output low level (0V level) signals.

  5) The coincidence detection circuit 70 determines whether all the cell voltages of the battery cells 10A to 10E have reached the charge control start voltage (see S105).

  6) When any one of the battery cells 10A to 10E reaches the charge control start voltage, the charge / discharge end detection circuit 90 outputs a high level signal to the control device 80. When all the cell voltages of the battery cells 10 </ b> A to 10 </ b> E have not reached the charge control start voltage, the coincidence detection circuit 70 outputs a low level signal to the control device 80. As a result, based on the output signals from the coincidence detection circuit 70 and the charge / discharge end detection circuit 90, the control device 80 responds to the switch control circuits 95A to 95E according to the outputs from the voltage monitoring circuits 40A to 40E. A control signal for controlling opening and closing of 30E is output. The switch control circuits 95A to 95E output switch control signals based on the outputs from the corresponding voltage monitoring circuits 40A to 40E in response to instructions from the control device 80. If any of the outputs from the voltage monitoring circuits 40A to 40E indicates that any one of the battery cells 10A to 10E has reached the charge control start voltage, the battery cell 10A In this embodiment, the bypass circuit switch connected in parallel to the battery cell is closed (on state) and the bypass connected in parallel to the other battery cells in order to reduce the charging current flowing through 10E to 10E. The circuit switch is left open (off state) (see S106).

  For example, when the cell voltage of the battery cell 10C reaches the charge control start voltage, the switch 30C is closed (ON state) from the switch control circuit 95C corresponding to the battery cell 10C determined to have reached the charge control start voltage. ) And switch control circuits 95A, 95B, 95D, and 95E corresponding to the battery cells 10A, 10B, 10D, and 10E that have not reached the charging control start voltage respectively correspond to the switches 30A, 30B, 30D, and A signal that keeps 30E open (off state) is output.

  As a result, since the bypass circuit composed of the impedance element 20C and the switch 30C becomes effective by closing the switch 30C, the charging current supplied to the battery cell 10C also flows to the bypass circuit, and the battery The amount of charging current supplied to the cell 10C is reduced. In order to validate the bypass circuit of the target battery cells 10A, 10B, 10D, and 10E each time charging progresses and the cell voltages of the battery cells 10A, 10B, 10D, and 10E reach the charge control start voltage The target switches 30A, 30B, 30D, and 30E are closed.

  7) As a result of such control, when the coincidence detection circuit 70 detects that all the cell voltages of the battery cells 10A to 10E have reached the charge control start voltage, a signal indicating that the coincidence is detected by the control device 80 In this embodiment, a high level signal is sent. As a result, according to the signal, control device 80 instructs storage circuit 60 to store data corresponding to the full charge detection voltage value, which is the next set voltage during charging, in storage circuit 50. Thus, data corresponding to the full charge detection voltage value is read from the storage circuit 60 and output to the storage circuit 50, whereby data corresponding to the full charge detection voltage value is stored in the storage circuit 50. The data stored in the storage circuit 50 is sent to the voltage monitoring circuits 40A to 40E, and the control device 80 instructs the switch control circuits 95A to 95E to return all the switches 30A to 30E to the open state (see S107). ). As the switches 30A to 30E are opened (off state), the output of the coincidence detection circuit 70 also returns to the low level signal, and the output of the charge / discharge end detection circuit 90 also returns to the low level signal. .

  8) Thereafter, each of the voltage monitoring circuits 40A to 40E performs a predetermined measurement for monitoring the cell voltages of the target battery cells 10A to 10E, and the measured cell voltage is converted into digital data and sent from the storage circuit 50. It is compared with the data corresponding to the full charge detection voltage value coming (see S108).

  9) As a result of the comparison by the voltage monitoring circuit in S108, the voltage monitoring circuits 40A to 40E determine that any one of the battery cells 10A to 10E has reached the full charge detection voltage. In response to the output signal from the end detection circuit 90 becoming a high level, the control device 80 performs a process for terminating the charging (see S109).

  As described above in detail, in the power storage device I according to the present embodiment, two threshold voltages (a charge control start voltage and a full charge detection voltage) are provided to control charging in two stages. In particular, when the cell voltages of all the battery cells reach the charging control start voltage, all the switches 30A to 30E constituting the bypass circuit are once returned to the open state to invalidate the bypass circuit and reach the full charge detection voltage. To charge up to. As described above, since the charging current until reaching the full charge detection voltage is increased again, the time for bypass control can be shortened, and the power consumed by the bypass can be expected to be reduced.

  In addition, the charging time from the charging control start voltage to the full charge detection voltage can be shortened. As a result, it is possible to suppress overcharging and realize efficient charging.

<Control during discharge operation>
1) The discharge process starts when the control device 80 recognizes that the power storage device I is in a discharged state by automatic processing when the discharge instruction from the operation unit (not shown) or the connection of the load 110 is recognized. (See S201). At this time, the control device 80 generates an output instruction signal for reading out the data corresponding to the set voltage used for monitoring the cell voltage during discharge from the storage circuit 60 and outputting it. The set voltage at the time of discharge includes a discharge lower limit detection voltage for detecting that the discharge lower limit has been reached, and a discharge control start voltage higher than the discharge lower limit detection voltage. Here, the storage circuit 60 stores data corresponding to the discharge lower limit detection voltage value and the discharge control start voltage value. At the time of discharge, first, data corresponding to the discharge control start voltage value is read from the storage circuit 60 and output in accordance with an output instruction signal from the control device 80, so that data corresponding to the discharge control start voltage value is stored in the storage circuit. 50.

  2) The data stored in the storage circuit 50 is sent to the voltage monitoring circuits 40A to 40E (see S202).

  3) The voltage monitoring circuits 40A to 40E perform measurements for monitoring the cell voltages of the target battery cells 10A to 10E, respectively (see S203).

  4) The voltage monitoring circuits 40A to 40E compare the measured cell voltage with data corresponding to the discharge control start voltage value sent from the storage circuit 50 as digital data. As a result of the comparison, each of the voltage monitoring circuits 40A to 40E outputs a signal indicating a determination result as to whether or not any of the battery cells 10A to 10E monitored by itself has reached the discharge control start voltage (see S204). . For example, when the voltage monitoring circuit 40C determines that the cell voltage of the battery cell 10C to be monitored has reached the discharge control start voltage, the voltage monitoring circuit 40C outputs, for example, a high level signal, and monitors other voltages. The circuits 40A, 40B, 40D, and 40E output a low level signal.

  5) The coincidence detection circuit 70 determines whether or not all the cell voltages of the battery cells 10A to 10E have reached the discharge control start voltage (see S205).

  6) When any of the battery cells 10A to 10E reaches the discharge control start voltage, the charge / discharge end detection circuit 90 outputs a high level signal to the control device 80. When all the cell voltages of the battery cells 10A to 10E have not reached the discharge control start voltage, the coincidence detection circuit 70 outputs a low level signal to the control device 80. As a result, based on the output signals from the coincidence detection circuit 70 and the charge / discharge end detection circuit 90, the control device 80 responds to the switch control circuits 95A to 95E according to the outputs from the voltage monitoring circuits 40A to 40E. A control signal for controlling opening and closing of 30E is output. The switch control circuits 95A to 95E output switch control signals based on the outputs from the corresponding voltage monitoring circuits 40A to 40E in response to instructions from the control device 80. If any of the outputs from the voltage monitoring circuits 40A to 40E indicates that any one of the battery cells 10A to 10E has reached the charge control start voltage, the battery cell 10A In this embodiment, the bypass circuit switch connected in parallel to the battery cell is left in the open state (off state) and is connected in parallel to the other battery cells in order to reduce the charging current flowing through 10E to 10E. The bypass circuit switch is closed (ON state) (see S206).

  For example, when the cell voltage of the battery cell 10C reaches the discharge control start voltage, the switch 30C is opened (off state) from the switch control circuit 95C corresponding to the battery cell 10C determined to have reached the discharge control start voltage. The switch control circuits 95A, 95B, 95D, and 95E corresponding to the battery cells 10A, 10B, 10D, and 10E that have not reached the discharge control start voltage are output from the corresponding switches 30A, 30B, A signal for turning off 30D and 30E (ON state) is output.

  As a result, by closing the switches 30A, 30B, 30D, and 30E, the bypass circuit composed of the impedance elements 20A, 20B, 20D, and 20E and the switches 30A, 30B, 30D, and 30E becomes effective, and a closed loop is formed. Therefore, the amount of discharge current for the battery cells 10A, 10B, 10D, and 10E that has not reached the charge control start voltage is increased. In order to invalidate the bypass circuit of the target battery cell 10A, 10B, 10D, 10E each time the discharge proceeds and the cell voltage of the battery cell 10A, 10B, 10D, 10E reaches the discharge control start voltage The target switches 30A, 30B, 30D, and 30E are opened.

  7) As a result of such control, when the coincidence detection circuit 70 detects that all the cell voltages of the battery cells 10A to 10E have reached the discharge control start voltage, In this embodiment, a high level signal is sent. As a result, in response to the signal, control device 80 instructs storage circuit 60 to store data corresponding to the discharge lower limit detection voltage value, which is the next set voltage during discharge, in storage circuit 50. Thus, data corresponding to the discharge lower limit detection voltage value is read from the storage circuit 60 and output to the storage circuit 50, whereby data corresponding to the discharge lower limit detection voltage value is stored in the storage circuit 50. The data stored in the storage circuit 50 is sent to the voltage monitoring circuits 40A to 40E (see S207).

  8) Thereafter, each of the voltage monitoring circuits 40A to 40E performs a predetermined measurement for monitoring the cell voltages of the target battery cells 10A to 10E, and the measured cell voltage is converted into digital data and sent from the storage circuit 50. It is compared with data corresponding to the incoming discharge lower limit detection voltage value (see S208).

  9) As a result of comparison in the voltage monitoring circuit in S208, it is determined by the voltage monitoring circuits 40A to 40E that any one of the battery cells 10A to 10E has further decreased to reach the discharge lower limit detection voltage. Then, in response to the output signal from the charge / discharge end detection circuit 90 becoming a high level, the control device 80 performs a process for terminating the discharge (see S209).

  As described above in detail, in the power storage device I according to the present embodiment, two threshold voltages (discharge control start voltage, discharge lower limit detection voltage) are provided to control discharge in two stages. In particular, when any one of the battery cells 10A to 10E reaches the discharge control start voltage, all the switches 30A to 30E constituting the bypass circuit arranged in parallel with the battery cells 10A to 10E other than the battery cells 10A to 10E are closed. After each of the battery cells 10A to 10E reaches the discharge control start voltage after the switches 30A to 30E of the battery cells 10A to 10E are opened each time the discharge control start voltage is reached. The switches 30A to 30E are discharged until the battery cells 10A to 10E reach the discharge lower limit detection voltage. In this way, for all battery cells, the discharge current until reaching the discharge lower limit detection voltage is performed with the current value in a state where the bypass circuit is invalidated, so the time for bypass control can be shortened, and by bypass It can be expected to reduce the power consumed.

  In addition, the charging time from the discharge control start voltage to the discharge lower limit detection voltage can be shortened. As a result, overdischarge can be suppressed and efficient discharge can be realized.

  In addition, this invention is not limited to what is shown to embodiment mentioned above, It can change in the range which does not deviate from the meaning of this invention.

  For example, the control device according to the present invention operates each current control unit as described above with a full charge detection voltage and a charge control start voltage lower than the full charge detection voltage, or discharge lower limit detection voltage and discharge lower limit detection voltage. A configuration in which each current control means is operated as described above at a higher discharge control start voltage is included in the technical idea of the present invention. Therefore, instead of using the memory circuit 60 or the storage circuit 50, each current control unit is provided with each current control unit having a full charge detection voltage and a charge control start voltage lower than the full charge detection voltage as parameters. Alternatively, each current control unit may be operated as described above by causing each current control unit to have as a parameter a discharge lower limit detection voltage and a discharge control start voltage higher than the discharge lower limit detection voltage. it can.

  Further, it is not necessary to limit the current control means to a bypass circuit formed by connecting impedance elements 20A to 20E and switches 30A to 30E connected in series. Although the above embodiment can be realized with a simple circuit configuration, it is provided corresponding to each battery cell 10A to 10E, and the charging current or discharging current flowing through each battery cell 10A to 10E is independent. If the configuration is such that it can be controlled, the present invention can be applied. Of course, the number of battery cells 10A to 10E that are connected in series to form the battery cell unit 10 is arbitrary.

  Further, the coincidence detection circuit 70 and the charge / discharge end detection circuit 90 are not limited to the above-described configuration, and the coincidence detection circuit 70 may be a negative OR gate, and the charge / discharge end detection circuit 90 is a negative AND gate. There may be. Thus, as long as the same function is exhibited, it does not prevent the coincidence detection circuit 70 and the charge / discharge end detection circuit 90 from having other configurations.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used in an industrial field in which a power storage device as a DC power supply is manufactured and sold and a power supply system using the power storage device is constructed.

I Power storage device 1 Control means 10 Battery cell unit 10A to 10E Battery cell 20A to 20E Impedance element 30A to 30E Switch 100 Power supply 110 for charging Load

Claims (7)

A battery cell unit configured by connecting a plurality of battery cells in series;
Current control means provided to correspond to the plurality of battery cells, and independently controlling charge and discharge currents flowing through the battery cells;
Control means for controlling the charge / discharge current flowing through each battery cell via the current control means based on the cell voltage of each battery cell;
The control means has a full charge detection voltage, a charge control start voltage lower than the full charge detection voltage, a discharge lower limit detection voltage and a discharge control start voltage higher than the discharge lower limit detection voltage as parameters, and charging operation Sometimes, when any of the cell voltages reaches the charge control start voltage, the charge current supplied to the battery cell that has reached the charge control start voltage is reduced by setting the current control means to the first state. In addition, when the cell voltages of all the battery cells reach the charge control start voltage, the current control means is set to the second state to charge the reduced charge current again and charge any battery cell. When the cell voltage reaches the full charge detection voltage, the charging operation is terminated, while during the discharging operation, when any cell voltage reaches the discharge control start voltage, The discharge current discharged from the battery cells that have not reached the discharge control start voltage by the control means is increased, and after the cell voltages of all the battery cells have reached the discharge control start voltage, The battery device is configured to terminate the discharge operation when the cell voltage of the battery cell reaches the discharge lower limit detection voltage. A battery cell unit configured by connecting a plurality of battery cells in series;
Current control means provided to correspond to the plurality of battery cells and independently controlling a charging current flowing through each of the battery cells;
Control means for controlling the charging current flowing through each battery cell via the current control means based on the cell voltage of each battery cell, and
In the control means, a full charge detection voltage and a charge control start voltage lower than the full charge detection voltage are set as parameters, and when any of the cell voltages reaches the charge control start voltage during a charging operation, The charging is continued with the charging current supplied to the battery cell that has reached the charging control start voltage being reduced by setting the current control means to the first state, and the cell voltages of all the battery cells start charging control. When the voltage is reached, the current control means is set to the second state to charge the reduced charging current again, and charging is completed. When the cell voltage of any battery cell reaches the full charge detection voltage, the charging operation is terminated. It is comprised as follows. The electrical storage apparatus characterized by the above-mentioned. A battery cell unit configured by connecting a plurality of battery cells in series;
Current control means provided to correspond to the plurality of battery cells and independently controlling a discharge current flowing through each of the battery cells;
Control means for controlling the discharge current flowing through each battery cell via the current control means based on the cell voltage of each battery cell, and
In the control means, a discharge lower limit detection voltage and a discharge control start voltage higher than the discharge lower limit detection voltage are set as parameters, and when any cell voltage reaches the discharge control start voltage during the discharge operation, After controlling the current control means to increase the discharge current discharged from the battery cells that have not reached the discharge control start voltage, and after the cell voltages of all the battery cells have reached the discharge control start voltage The power storage device is configured to terminate the discharge operation when the cell voltage of any one of the battery cells reaches the discharge lower limit detection voltage. In the electrical storage apparatus as described in any one of Claims 1-3,
The current control means is composed of a plurality of bypass circuits each having a configuration in which an impedance element and a switch means are connected in series and connected in parallel to the battery cells, respectively.
The power storage device according to claim 1, wherein the control means controls opening and closing of the switch means based on monitoring results of a plurality of voltage monitoring circuits that monitor cell voltages of the battery cells. A method of charging and discharging a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series,
At the time of charging, when any one of the cell voltages reaches a charge control start voltage set in advance as a voltage lower than a full charge detection voltage indicating full charge, provided corresponding to each battery cell, and The charging current supplied to the battery cell that has reached the charging control start voltage is reduced by setting the current control means for independently controlling the charging current flowing through each battery cell to the first state, and When the cell voltages of all the battery cells reach the charge control start voltage, the current control means is set to the second state to recharge the reduced charge current again and charge any one of the battery cells. While the voltage reaches a full charge detection voltage higher than the charge control start voltage, the charging operation is terminated,
At the time of discharge, when any one of the cell voltages reaches a discharge control start voltage preset as a voltage higher than a discharge lower limit detection voltage indicating that it is a discharge lower limit voltage, it is provided corresponding to each battery cell, And the discharge current discharged from the battery cell that has not reached the discharge control start voltage is increased by the current control means for independently controlling the discharge current flowing through each battery cell, and all the battery cells A charging / discharging method for a power storage device, wherein after the cell voltage reaches the discharge control start voltage and the cell voltage of any one of the battery cells reaches the discharge lower limit detection voltage, the discharge operation is terminated. . A method for charging a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series,
When any one of the cell voltages reaches a charge control start voltage set in advance as a voltage lower than the full charge detection voltage, a charging current provided corresponding to each battery cell and flowing through each battery cell is independently generated. In the first state of the current control means to be controlled , charging is continued in a state where the charging current supplied to the battery cell that has reached the charging control start voltage is reduced, and the cell voltages of all the battery cells are When the charge control start voltage is reached, charging is performed by increasing again the charge current that has been reduced by setting the current control means to the second state, and the cell voltage of any battery cell is greater than the charge control start voltage. A charging method for a power storage device, wherein the charging operation is terminated when reaching a higher full charge detection voltage. A method for discharging a power storage device having a battery cell unit configured by connecting a plurality of battery cells in series,
When any one of the cell voltages reaches a discharge control start voltage set in advance as a voltage higher than the discharge lower limit detection voltage, a discharge current provided corresponding to each battery cell and flowing through each battery cell is independently generated. The discharge current discharged from the battery cells that have not reached the discharge control start voltage is increased by the current control means that controls, and the cell voltages of all the battery cells have reached the discharge control start voltage. A discharging method for a power storage device, characterized in that after the cell voltage of any one of the battery cells reaches the discharge lower limit detection voltage, the discharging operation is terminated.

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