JP2008043009A - Battery pack and control method - Google Patents

Abstract

Charge and discharge are efficiently performed on a plurality of cell blocks.
The battery unit 10 has different paths for charging and discharging, and charging control switches 23a and 23b and discharging control switches 24a and 24b are provided in the respective paths. During charging, the charging control switches 23 a and 23 b are turned on based on the control of the charging / discharging control unit 22, and a charging current flows through the cell block 21. During discharge, the discharge control switches 24 a and 24 b are turned on, and a discharge current flows from the cell block 21. When the voltage of the battery cell 40 is reduced and an overdischarge state occurs, a cell block is formed by directly connecting the discharge positive electrode terminal 29a and the discharge negative electrode terminal 29b by turning on a bypass switch provided in the discharge path. 21 overdischarge is prevented. In this way, the current paths are switched, and a plurality of battery units 10 are connected in parallel at the time of charging, and are connected in series at the time of discharging.
[Selection] Figure 2

Description

  The present invention relates to a battery pack that efficiently charges and discharges and a control method thereof.

  In recent years, portable electronic devices such as notebook PCs (Personal Computers), mobile phones, and PDAs (Personal Digital Assistants) have become widespread, and lithium-ion secondary batteries having advantages such as high voltage, high energy density, and light weight are widely used as power sources. in use. This lithium-ion secondary battery can also be used as a secondary battery for high-power capacitors such as electric vehicles, hybrid vehicles, UPS (Uninterruptible Power Supply) and solar power generators, taking advantage of the advantages described above. It has come to be.

  When a secondary battery is used to output a large amount of power, usually a plurality of battery cell sets in which a plurality of battery cells called cell blocks are connected in series and / or in parallel are used, and a large amount of power is supplied to the device. I am trying to supply.

  Thus, the technique regarding the battery pack using the cell block which connected the some battery cell in series and / or in parallel is described in the following patent document 1. FIG.

JP 2002-204534 A

  When charging the above-described cell block, the charging voltage from the charger is a value obtained by multiplying the charging voltage of one battery cell by the number of battery cells in series. Therefore, by reducing the number of battery cells in series, the charging voltage of the charger can be lowered and charging can be performed efficiently. In this case, however, the discharging voltage at the time of discharging is lowered. Therefore, when trying to output a large amount of power during discharge, the discharge voltage must be increased because the discharge voltage is low, and heat loss due to line resistance increases, resulting in a deterioration in discharge efficiency. There was a problem.

  On the other hand, in order to reduce the heat loss at the time of discharge, by increasing the number of battery cells in series, the discharge voltage can be increased and high power can be output efficiently. However, when the number of battery cells in series is increased, the charging voltage at the time of charging increases, so that a charger capable of outputting a high voltage is required. A charger that can output a high voltage is difficult to handle, and the use of a booster circuit for charging is inefficient.

  Thus, when charging, it is necessary to reduce the number of series of battery cells in order to lower the charging voltage, and to increase the number of series of battery cells in order to output a high voltage during discharging. . Therefore, a contradiction arises in order to charge and discharge efficiently.

  Moreover, when charging the battery cell used for a cell block, constant current constant voltage charge is normally used. When charging one battery cell, the battery cell can always be fully charged by using constant current constant voltage charging. However, when this charging method is used for a cell block, if the battery capacity of each cell block is different, one of the battery cells connected in series is fully charged. Since charging is stopped at a stage, the remaining battery cells cannot be fully charged.

  The same applies to a plurality of cell blocks. For example, when a plurality of cell blocks having different characteristics such as battery capacity are connected, conventionally, when one of the plurality of cell blocks connected in series is fully charged at the time of charging, There was a problem that charging was stopped and the remaining cell blocks could not be fully charged.

  Furthermore, when the battery cell used for the cell block deteriorates or fails, the influence of the deterioration or failure of the battery cell affects the entire cell block. Therefore, it is necessary to replace a deteriorated or failed battery cell, but it is necessary to align the characteristics of the battery cell used in the cell block, so that it is difficult to replace only the battery cell in which the problem has occurred. was there.

  Accordingly, an object of the present invention is to provide a battery pack that can efficiently charge and discharge a plurality of cell blocks and a control method thereof.

  In order to solve the above-described problem, the first invention includes a plurality of battery units connected in series and in parallel, and a first control unit that controls charging / discharging of the plurality of battery units. The battery unit detects a battery block in which battery cells of one or a plurality of secondary batteries are connected in series and / or in parallel, and a charge / discharge state of the cell block, and supplies a detection result to the first controller. A second control unit that receives a command according to a detection result by the first control unit and controls charge / discharge of the cell block based on the command; and a charge control switch that is turned on / off based on the control by the second control unit And a discharge control switch that is turned on / off based on control by the second control unit, wherein the first control unit determines charge / discharge states of the plurality of battery units based on the detection result, and When at least one battery unit of the knit is not fully charged, a charge command is supplied to the battery unit, and when all of the battery units are fully charged, a discharge command is issued to the plurality of battery units. The second control unit turns on the charge control switch based on the charge command from the first control unit, turns off the discharge control switch, and connects the plurality of battery units in parallel. The battery pack is characterized in that the discharge control switch is turned on based on the discharge command from the control unit, the charge control switch is turned off, and a plurality of battery units are connected in series.

  Moreover, 2nd invention is the charge / discharge state of the cell block in which the 1 or several battery cell provided in the several battery unit connected in series and in parallel was connected in series and / or in parallel. A detection step of detecting by the control unit, a supply step of supplying charge / discharge commands to the plurality of battery units from the first control unit that controls charging / discharging of the plurality of battery units based on the detection result, A control step of controlling charging / discharging of the cell block by the second control unit based on a charge / discharge command by the control unit, and in the supplying step, the charge / discharge states of the plurality of battery units are determined based on the detection result, When at least one of the battery units is not fully charged, a charge command is supplied from the first control unit to the battery unit, and the plurality of battery units When all are fully charged, a discharge command is supplied from the first control unit to the plurality of battery units, and in the control step, based on the charge command from the first control unit, the second control unit A plurality of battery units are connected in parallel by turning on a charge control switch that is turned on / off according to control and turning off a discharge control switch that is turned on / off according to control by the second control unit. The control method is characterized in that the discharge control switch is turned on based on a discharge command from the first control unit, the charge control switch is turned off, and a plurality of battery units are connected in series.

  As described above, in the first and second inventions, in the second control unit, the charge / discharge state of the cell block is detected, and the first control unit charges / discharges the plurality of battery units based on the detection result. The command is supplied, the charge control switch is turned on based on the charge command from the first control unit, the discharge control switch is turned off, and the discharge control switch is turned on based on the discharge command from the first control unit. In addition, since the charging control switch is turned off, a plurality of battery units are connected in parallel during charging, and a plurality of battery units are connected in series during discharging.

  In this invention, when charging, a plurality of battery units are connected in parallel, and when discharging, a plurality of battery units are connected in series. It can output and can charge / discharge efficiently about several battery units.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In one embodiment of the present invention, a plurality of cell blocks comprising a plurality of battery cells connected in series and / or in parallel are provided, the cell blocks are connected in parallel during charging, and in the case of discharging, the cell blocks are connected in series. By connecting, charging and discharging are performed efficiently.

  First, the configuration of an example of a battery pack 1 according to an embodiment of the present invention will be described with reference to FIG. The battery pack 1 includes one or a plurality of battery units 10, 10,... And an integrated control unit 11.

  The battery units 10, 10,... Have a cell block in which a plurality of battery cells are connected in series and / or in parallel, and a charging positive terminal 28a and a charging negative terminal 28b that are charging electrode terminals. The discharge positive electrode terminal 29a and the discharge negative electrode terminal 29b, which are electrode terminals for discharge, and the control terminal 30 for transferring information relating to charging / discharging of the battery unit 10 are provided. Details of the battery unit 10 will be described later.

  The charging positive terminal 28 a and the charging negative terminal 28 b of each battery unit 10, 10... Are connected in parallel and connected to the positive terminal and the negative terminal of the external charger 12. Charging is performed on the battery cells stored in the interior of the battery 10. In addition, the discharge positive terminal 29a and the discharge negative terminal 29b of each battery unit 10, 10,... Are connected in series, and the discharge positive terminal 29a of the front battery unit 10 and the battery unit 10 of the last stage are connected. The discharge negative electrode terminal 29b is connected to the positive electrode terminal and the negative electrode terminal of the external load 13, and the load 13 is discharged.

  The integrated control unit 11 determines the battery units 10, 10,... According to the charge / discharge state based on the charge / discharge information supplied from each battery unit 10, 10,. Controls charging / discharging. The integrated control unit 11 receives a full charge signal indicating that the cell block is fully charged from each battery unit 10, 10,... And a complete discharge signal indicating that the cell block is fully discharged. 30 via. And based on a full charge signal and a complete discharge signal, the command of discharge and charge is transmitted with respect to each battery unit 10,10, .... Further, the integrated control unit 11 detects a connection state between the battery units 10, 10,... And the charger 12. For example, the integrated control unit 11 can measure the voltage of the electrode terminal of the charger 12 and detect the connection state based on the magnitude or presence of the measured voltage. Further, for example, the integrated controller 11 receives a connection signal indicating whether or not the charger 12 and the battery units 10, 10,... Are connected from the charger 12 to detect the connection state. It may be. In addition, the detail of the control method of each battery unit 10,10, ... by the integrated control part 11 is mentioned later.

  Next, the configuration of an example of the battery unit 10 applicable to the embodiment of the present invention will be described with reference to FIG. The battery unit 10 includes a cell block 21, a charge / discharge control unit 22, charge control switches 23 a and 23 b, discharge control switches 24 a and 24 b, a bypass switch 25, a current detection resistor 26, and a fuse 27. Further, the battery unit 10 is provided with a charge positive terminal 28a, a charge negative terminal 28b, a discharge positive terminal 29a, a discharge negative terminal 29b, and a control terminal 30 for connection to the outside.

  Further, the battery unit 10 has a charging path and a discharging path, and by switching on / off a switch provided in each path, the path through which the current flows is switched during charging or discharging. Yes.

  The charging positive terminal 28 a and the charging negative terminal 28 b are connected to the positive terminal and the negative terminal of the charger 12. Furthermore, the discharge positive electrode terminal 29a and the discharge negative electrode terminal 29b are connected to the discharge negative electrode terminal 29b and the subsequent discharge positive electrode terminal 29a of the battery unit 10 at the preceding stage, respectively. In charging, electric power is supplied from the charger 12 to the cell block 21 via the charging positive terminal 28a and the charging negative terminal 28b, and in discharging, the discharging positive terminal 29a and the discharging negative terminal 29b are discharged. Electric power is supplied from the cell block 21 to the load 13 via.

  The cell block 21 is configured by connecting a plurality of battery cells 40, 40,... In series and / or in parallel.

  In order to efficiently charge and discharge the plurality of battery cells 40, 40,..., Batteries having the same characteristics such as battery capacity are used. For example, when charging is performed using battery cells having different battery capacities, when any of the battery cells connected in series is fully charged, the remaining battery cells are fully charged. This is because, when discharging is performed, if any of the battery cells connected in series is completely discharged, discharging cannot be continued from the remaining battery cells.

  Therefore, the number of battery cells 40, 40,... Connected in series needs to have the same characteristics such as battery capacity and the voltage supplied from the charger used for charging. In this case, for example, it is preferable to have up to about 4 series 4 parallel.

  The charge / discharge control unit 22 monitors the state of the battery unit 10, supplies various signals related to charge / discharge to the integrated control unit 11 via the control terminal 30, and is based on the charge / discharge command supplied from the integrated control unit 11. The charging / discharging of the battery cell 40 is controlled.

  The charge / discharge control unit 22 measures the voltage of each battery cell 40, 40,... In the cell block 21, converts the voltage applied to the current detection resistor 26 into a current, and measures the charge / discharge current. . The charging / discharging control unit 22 monitors the charging / discharging state of the cell block 21 based on the measured voltage of each battery cell 40, 40,..., And in the fully charged state, the cell block 21 is fully charged. A full charge signal indicating the presence is generated and output to the integrated control unit 11. In addition, the charge / discharge control unit 22 generates a complete discharge signal indicating that the cell block 21 is completely discharged in the complete discharge state, and outputs the complete discharge signal to the integrated control unit 11.

  In addition, when using a lithium ion secondary battery as the battery cell 40 used for the cell block 21, for example, when the voltage of the battery cell 40 is 3 V (volts), the capacity becomes “0” and the battery cell 40 is completely discharged. It is considered. When the voltage reaches 2.5V, it is regarded as overdischarge and discharge is prohibited.

  Further, the charge / discharge control unit 22 performs a failure diagnosis of the cell block 21 and, when determining that the cell block 21 has failed, sends an error signal indicating the failure of the cell block 21 to the integrated control unit 11. Output. As a failure diagnosis method, for example, a known method can be applied.

  Further, the charge / discharge control unit 22 controls each switch to perform charging or discharging based on a command from the integrated control unit 11. During charging, the charge / discharge control unit 22 turns on the charge control switches 23a and 23b and turns off the discharge control switches 24a and 24b, so that a charging current flows from the charger 12 to the cell block 21. Like that. When the cell block 21 is fully charged, all switches are turned off so that no charging current flows to the cell block 21.

  When discharging, the charge / discharge control unit 22 turns on the discharge control switches 24a and 24b and turns off the charge control switches 23a and 23b so that the discharge current is supplied from the cell block 21 to the load 13. Make it flow. When the cell block 21 is completely discharged, each switch is controlled so that no discharge current flows from the cell block 21. Further, the charge / discharge control unit 22 turns off the charge control switches 23a and 23b and the discharge control switches 24a and 24b and turns on the bypass switch 25 to prevent the cell block 21 from being overdischarged. The cell block 21 is bypassed.

  In addition, when the cell block 21 is in an overcurrent state due to a failure of the charger or the like, or the voltage of the battery cell 40 is in an overvoltage state, the charge / discharge control unit 22 detects an overcurrent signal indicating an overcurrent state or an overvoltage state. Is supplied to the integrated control unit 11. Then, the fuse 27 is blown, and the charge / discharge current path for the cell block 21 is interrupted.

  The charging control switches 23 a and 23 b are provided on the charging current path, and are turned on / off based on the control of the charging / discharging control unit 22. At the time of charging, the charging control switches 23 a and 23 b are turned on so that charging current is supplied to the cell block 21. Further, at the time of discharging, the charging control switches 23a and 23b are turned off, and the charging current for the cell block 21 is cut off.

  The discharge control switches 24 a and 24 b are provided on the discharge current path, and are turned on / off based on the control of the charge / discharge control unit 22. At the time of discharge, the discharge control switches 24 a and 24 b are turned on, and a discharge current flows from the cell block 21. Further, at the time of charging, the discharge control switches 24a and 24b are turned off, and the discharge current from the cell block 21 is cut off.

  The bypass switch 25 is provided on a path connecting the discharge positive electrode terminal 29 a and the discharge negative electrode terminal 29 b, and is turned on / off based on the control of the charge / discharge control unit 22. The bypass switch 25 is normally turned off, and is turned on when the cell block 21 is in a completely discharged state. The bypass switch 25 is directly connected to the discharge positive electrode terminal 29a and the discharge negative electrode terminal 29b so that the excess of the cell block 21 is detected. Discharge can be prevented.

  Examples of the charge control switches 23a and 23b, the discharge control switches 24a and 24b, and the bypass switch 25 include mechanical switches such as relays, MOS-FETs, IGBTs (Insulated Gate Bipolar Transistors), and GTO thyristors (Gate Turn Off). Any electrical switch using a semiconductor element such as a thyristor can be used. In consideration of switching time, contact resistance, contact loss at the time of switching, contact deterioration degree, and the like, it is preferable to use an electrical switch, and it is more preferable to use a MOS-FET that is a switch of a semiconductor element.

  The fuse 27 is provided on the charge / discharge current path, and melts when the temperature around the fuse 27 reaches a predetermined temperature due to an abnormal current or the like, thereby blocking the charge / discharge current flowing through the current path. Further, the fuse 27 is blown when the ambient temperature rises based on the control from the charge / discharge control unit 22.

  Next, control of the battery units 10, 10,... By the integrated control unit 11 will be described with reference to the state transition diagram of the integrated control unit 11 shown in FIG. The integrated control unit 11 controls charging / discharging of the battery units 10, 10,... Based on the full charge signal and the complete discharge signal supplied from the battery units 10, 10,.

  In sequence SEQ1, the integrated control unit 11 is activated, and the process proceeds to sequence SEQ2. In sequence SEQ2, the integrated control unit 11 is initialized, receives a full charge signal and a complete discharge signal from each battery unit 10, and monitors the charge / discharge state of the battery unit 10. If all the battery units 10 are fully charged, or if no charger is connected, the process proceeds to sequence SEQ3. If all the battery units 10 are in a completely discharged state and no charger is connected, the process proceeds to sequence SEQ5. Further, in cases other than those described above, for example, when there is one or more battery units 10 that are connected to a charger and are not fully charged, the process proceeds to sequence SEQ4.

  In sequence SEQ <b> 3, the integrated control unit 11 transmits a discharge command to all the battery units 10. If there is one or more battery units 10 that are connected to the charger and are not fully charged, and no discharge current is flowing, the process proceeds to sequence SEQ4. If all the battery units 10 are in a fully discharged state, the process proceeds to sequence SEQ5. Furthermore, in cases other than those described above, for example, when all the battery units 10 are fully charged or when a discharge current is flowing, the processing of sequence SEQ3 is continued, and each battery unit 10 is The discharge command is transmitted as it is.

  In sequence SEQ <b> 4, the integrated control unit 11 transmits a charging command to all the battery units 10. When one or more battery units 10 that are not fully charged exist and a charger is connected, the process of sequence SEQ4 is continued, and a charge command is transmitted to each battery unit 10 as it is. If the charger is disconnected and all the battery units 10 are completely discharged, the process proceeds to sequence SEQ5. Further, in cases other than those described above, for example, when all the battery units 10 are in a fully charged state, or when one or more battery units 10 that are not fully charged are present, the charger is disconnected. Shifts to sequence SEQ3.

  In sequence SEQ <b> 5, the integrated control unit 11 releases the charge / discharge command for all the battery units 10. When the charger is connected, the process proceeds to sequence SEQ4. Further, in cases other than the above case, for example, when a charger is not connected, the processing of sequence SEQ5 is continued and the charge / discharge command for all the battery units 10 is released.

  As described above, the integrated control unit 11 determines the battery units 10, 10 based on the full charge signal and the complete discharge signal supplied from the battery units 10, 10,. ,..., A command for charging / discharging can be output, and charging / discharging of the battery units 10, 10,.

  Next, charge / discharge control by the charge / discharge control unit 22 will be described with reference to a state transition diagram of the charge / discharge control unit 22 shown in FIG. The charge / discharge control unit 22 controls each switch provided in the battery unit 10 based on the command from the integrated control unit 11 and the charge / discharge state of the cell block 21 to charge / discharge the cell block 21. Yes.

  In sequence SEQ11, the charge / discharge control unit 22 is initialized, and the voltage of the battery cells 40, 40,... And the charge / discharge current are measured every predetermined time. Further, the charge / discharge control unit 22 performs failure diagnosis as to whether or not the battery unit 10 has failed based on the measured voltage, charge / discharge current, etc. of the battery cells 40, 40,. If the result of failure diagnosis is normal, the process proceeds to sequence SEQ12. On the other hand, when a failure is detected, an error signal is output to the integrated control unit 11, and the process proceeds to sequence SEQ19.

  In sequence SEQ12, the charge / discharge control unit 22 turns off all the charge control switches (C-SW) 23a and 23b, the discharge control switches (D-SW) 24a and 24b, and the bypass switch (B-SW) 25. The charging and discharging of the cell block 21 is stopped, and a standby state is entered.

  When charging is instructed from the integrated control unit 11 and each of the battery cells 40, 40,... Is in a fully discharged state, the process proceeds to sequence SEQ13. When charging is instructed from the integrated control unit 11 and each of the battery cells 40, 40,... Is not fully charged or completely discharged, the process proceeds to sequence SEQ14. When charging is instructed from the integrated control unit 11 and each of the battery cells 40, 40,... Is fully charged, the process proceeds to sequence SEQ15.

  Further, when discharging is instructed from the integrated control unit 11 and each of the battery cells 40, 40,... Is fully charged, the process proceeds to sequence SEQ16. When discharge is instructed from integrated control unit 11 and each battery cell 40, 40,... Is not fully charged or completely discharged, the process proceeds to sequence SEQ17. When discharge is commanded from the integrated control unit 11 and each battery cell 40, 40,... Is in a complete discharge state, the process proceeds to sequence SEQ18.

  In sequence SEQ13, the charge / discharge control unit 22 controls the charge control switches 23a and 23b to be turned on, and controls the discharge control switches 24a and 24b and the bypass switch 25 to be turned off to wait for charging. . If the charging current is detected, the process proceeds to sequence SEQ14. When the charging command from the integrated control unit 11 is canceled, the process proceeds to sequence SEQ12. In cases other than those described above, the processing of sequence SEQ13 is continued.

  In the sequence SEQ14, the charge / discharge control unit 22 controls the charge control switches 23a and 23b to be turned on, and controls the discharge control switches 24a and 24b and the bypass switch 25 to be turned off. Charge the battery. In this case, since the cell block 21 is charged, a full charge signal is not output to the integrated control unit 11. When the voltage of battery cells 40, 40,... Reaches the fully charged voltage, the process proceeds to sequence SEQ15. When the charging command from the integrated control unit 11 is canceled, the process proceeds to sequence SEQ12. In cases other than those described above, the sequence SEQ14 is continued and the cell block 21 is charged.

  In sequence SEQ15, the charge / discharge control unit 22 controls all the charge control switches 23a and 23b, the discharge control switches 24a and 24b, and the bypass switch 25 to be turned off, and sends a full charge signal to the integrated control unit 11. Output, and the charging of the cell block 21 is stopped. When the charge command from integrated control unit 11 is canceled, the process proceeds to sequence SEQ12. In cases other than those described above, the processing of sequence SEQ15 is continued.

  In sequence SEQ16, the charge / discharge control unit 22 controls the discharge control switches 24a and 24b to be turned on, and controls the charge control switches 23a and 23b and the bypass switch 25 to be turned off to wait for discharge. To do. When the discharge current is detected, the process proceeds to sequence SEQ17. When the discharge command from the integrated control unit 11 is canceled, the process proceeds to sequence SEQ12. In cases other than those described above, the processing of sequence SEQ16 is continued.

  In sequence SEQ17, the charge / discharge control unit 22 controls the discharge control switches 24a and 24b to be turned on, and controls the charge control switches 23a and 23b and the bypass switch 25 to be turned off. To discharge. In this case, since the discharge is performed from the cell block 21, no complete discharge signal is output to the integrated control unit 11. When the voltage of battery cells 40, 40,... Becomes equal to or lower than the complete discharge voltage, the process proceeds to sequence SEQ18. When the discharge command from the integrated control unit 11 is canceled, the process proceeds to sequence SEQ12. In cases other than those described above, the processing of sequence SEQ17 is continued.

  In sequence SEQ18, the charge / discharge control unit 22 controls the charge control switches 23a and 23b, the discharge control switches 24a and 24b, and the bypass switch 25 to be all OFF, and sends a complete discharge signal to the integrated control unit 11. Output, and the discharge of the cell block 21 is stopped. When the discharge command from the integrated control unit 11 is canceled, the process proceeds to sequence SEQ12. In cases other than the above case, the processing of sequence SEQ18 is continued.

  In the sequence SEQ19, the charge / discharge control unit 22 controls the charge control switches 23a and 23b and the discharge control switches 24a and 24b to be turned off, and controls the bypass switch 25 to be turned on, thereby controlling the cell block 21. Charging / discharging is stopped, and the failed cell block 21 is bypassed. In addition, the charge / discharge control unit 22 outputs an error signal to the integrated control unit 11.

  Even during charging / discharging of the cell block 21, the charging / discharging control unit 22 measures the voltage and charging / discharging current of the battery cells 40, 40,... If a failure diagnosis is performed and it is determined that a failure has occurred, the process proceeds to sequence SEQ19.

  In this way, the charge / discharge control unit 22 can control charging / discharging of the cell block 21 by measuring the voltage of each battery cell 40, 40,... And the charging / discharging current every predetermined time. it can.

  As described above, in the embodiment of the present invention, the battery cells 40, 40,... Connected in series and / or in parallel are divided into cell blocks, and the respective battery units 10, 10,. -However, it is switched so that it is connected in parallel when charging, and is connected in series when discharging. Therefore, since the battery units 10, 10,... Are connected in parallel at the time of charging, charging can be performed using a low voltage power source. Further, since the battery units 10, 10,... Are connected in series at the time of discharge, a high voltage can be secured and the discharge current can be reduced, so that heat loss due to line resistance can be reduced. .

  Further, since this battery pack is composed of a plurality of divided battery units, the full charge voltage of the battery cells 40, 40,... Used for the cell block 21 provided in each battery unit is high. If it has, the battery cell of a different capacity | capacitance for every battery unit can be used.

  Furthermore, when discharging, conventionally, when any one of a plurality of battery units 10, 10,... Connected in series reaches a discharge end voltage, the discharge is stopped, and the remaining Although it was not possible to discharge from the battery unit, in one embodiment of the present invention, a path for bypassing the cell block was provided in the discharge path, and when the cell block was completely discharged or failed and the discharge stopped In addition, since the cell block can be bypassed, the remaining battery units can continue to be discharged.

  In addition, since the plurality of battery units are provided separately, it is possible to easily replace a failed battery unit or a deteriorated battery unit.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the embodiment of the present invention described above, and various modifications and applications can be made without departing from the gist of the present invention. Is possible.

It is a block diagram which shows the structure of an example of the battery pack by one Embodiment of this invention. It is a basic diagram which shows the structure of an example of a battery unit. It is a state transition diagram which shows an example of control of the battery unit by an integrated control part. It is a state transition diagram which shows an example of the charging / discharging control by a charging / discharging control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery pack 10 Battery unit 11 Integrated control part 12 Charger 13 Load 21 Cell block 22 Charge / discharge control part 23a, 23b Charge control switch 24a, 24b Discharge control switch 25 Bypass switch 26 Current detection resistance 27 Fuse 28a Charging positive terminal 28b Charging Negative terminal 29a Discharge positive terminal 29b Discharge negative terminal 30 Control terminal 40 Battery cell

Claims (5)

A plurality of battery units connected in series and in parallel;
A first control unit that controls charging / discharging of the plurality of battery units,
The plurality of battery units are
A cell block in which battery cells of one or more secondary batteries are connected in series and / or in parallel;
The charge / discharge state of the cell block is detected, the detection result is supplied to the first control unit, an instruction corresponding to the detection result by the first control unit is received, and the cell block is received based on the instruction. A second control unit for controlling charging and discharging;
A charge control switch that is turned ON / OFF based on the control by the second control unit;
A discharge control switch that is turned ON / OFF based on control by the second control unit,
The first controller is
Based on the detection result, the charging / discharging state of the plurality of battery units is determined. When at least one battery unit of the plurality of battery units is not fully charged, a charging command is supplied to the battery unit,
When the plurality of battery units are all fully charged, a discharge command is supplied to the plurality of battery units,
The second controller is
While turning on the charge control switch based on a charge command from the first control unit, turning off the discharge control switch, connecting the plurality of battery units in parallel,
A battery pack comprising: turning on the discharge control switch based on a discharge command from the first control unit; turning off the charge control switch; and connecting the plurality of battery units in series. The battery pack according to claim 1,
The second controller is
When charging, when the voltage of the battery cell becomes a full charge voltage indicating full charge as a result of the detection, the charge control switch is turned off to stop charging the battery cell. Battery pack. The battery pack according to claim 1,
The battery unit is
A bypass switch that is turned ON / OFF based on control by the second control unit;
The first controller is
Based on the detection result, when all of the plurality of battery units are completely discharged, an overdischarge protection command is transmitted to the plurality of battery units,
The second controller is
When an overdischarge protection command is received from the first control unit, the bypass switch is turned on and the charge control switch and the discharge control switch are turned off to stop the discharge from the cell block. A battery pack characterized by being controlled. The battery pack according to claim 3,
The second controller is
At the time of discharging, when the voltage of the battery cell becomes a complete discharge voltage indicating complete discharge as a result of the detection, the discharge control switch is turned off, the bypass switch is turned on, and the battery cell is turned on. A battery pack characterized by stopping the discharge from the battery pack. A detection step in which the second control unit detects a charge / discharge state of a cell block provided in a plurality of battery units connected in series and in parallel, in which one or a plurality of battery cells are connected in series and / or in parallel. When,
A supply step of supplying a charge / discharge command to the plurality of battery units from a first control unit that controls charge / discharge of the plurality of battery units based on the detection result;
A control step of controlling charging / discharging of the cell block by the second control unit based on the charge / discharge command by the first control unit,
In the above supply step,
Based on the detection result, charge / discharge states of the plurality of battery units are determined, and when at least one battery unit of the plurality of battery units is not fully charged, the first control unit applies to the battery units. Supply charging instructions,
When the plurality of battery units are all fully charged, a discharge command is supplied from the first control unit to the plurality of battery units,
In the above control step,
Based on the charging command from the first control unit, the charging control switch that is turned on / off according to the control by the second control unit is turned ON, and turned on according to the control by the second control unit The discharge control switch to be turned off is turned off, and the plurality of battery units are connected in parallel,
A control method comprising: turning on the discharge control switch based on a discharge command from the first control unit; turning off the charge control switch; and connecting the plurality of battery units in series.

Images