JP2017163749A - Secondary battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery system that monitors abnormality or the like of a secondary battery module in which a plurality of secondary batteries are connected in series and in parallel and can deal with abnormality without stopping operation.SOLUTION: A secondary battery system 1 includes: a plurality of secondary battery modules 6 in each of which a plurality of secondary battery cells 5 are connected in series and which are connected in parallel; a charging/discharging control unit 2 of the secondary battery system; an individual switch 8 for switching connection between each of the secondary battery modules 6 and the charging/discharging control unit 2; a CT 7 for measuring a current value for each secondary battery module 6; an ECU 9 for receiving information on the current value from the CT 7 and controlling on/off of the individual switch 8 according to the state of the received current value; a trunk switch 4 for connecting/disconnecting between the charging/discharging control unit 2 and each of the secondary battery modules 6; and a BMS 10 for monitoring and controlling the entire system, and performing on/off control of the trunk switch 4 on the basis of information obtained from the ECU 9.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a secondary battery system that performs multiple monitoring and control of a secondary battery system in cooperation with BMS, while independently monitoring an abnormality with each ECU (Electronic Control Unit) mounted on the secondary battery module. .

  As techniques for monitoring and controlling a plurality of secondary battery modules composed of a plurality of secondary battery cells, techniques disclosed in Patent Documents 1 to 3 are disclosed. In the technique shown in Patent Document 1, the power supply device 10 includes a battery module 1 in which a plurality of cells are connected in series, a monitoring ECU 2 that monitors an abnormality of the battery module 1, a ground terminal of the monitoring ECU 2, and a negative terminal of the battery module 1. A plurality of power supply units each having a diode 4 connected between the switch 4 and a switch means 3 connected to the negative terminal of the battery module 1 and the cathode of the diode 4 and controlled to be turned on / off by the monitoring ECU 2. The positive terminals of the battery modules 1 are commonly connected, the other ends of the switch means 4 are commonly connected, and the ground terminals of the monitoring ECUs 2 are commonly connected.

  The technology shown in Patent Document 2 includes a battery unit 2 formed by connecting a plurality of battery rows in which a plurality of secondary batteries are connected in series, a voltage equalization circuit 3 that reduces a voltage difference between the battery rows, In the power storage device 1 having the contactors 21, 22, and 23 provided between the battery rows 11, 12, and 13 and the load 10, the voltage equalization circuit 3 is connected to the battery rows 11, 12, and 13. A first resistor 24, 25, 26, a switching element 27 that electrically connects and disconnects the plurality of battery rows 11, 12, 13 via the first resistor 24, 25, 26, and a BMU 1 that controls the switching element 27 , BMU2 and BMU3 are provided, and after the system is stopped, the switching element 27 of the voltage equalization circuit 3 is turned on to reduce the voltage difference between the battery strings.

  In the technology shown in Patent Document 3, a secondary battery formed by connecting a plurality of battery cells to form one battery module closes a switch that opens and closes a short circuit that short-circuits the positive electrode and the negative electrode of the battery cell. The first voltage V ′ of the battery cell measured by the voltage measurement circuit in a state where the positive electrode and the negative electrode of the battery cell are short-circuited (s20), the voltage in a state where the switch is opened and the short-circuit circuit is cut off. The abnormality of the battery module is determined (s30) based on the difference from the second voltage V (s10) of the battery cell measured by the measurement circuit.

Japanese Patent Laying-Open No. 2015-80367 JP 2012-205407 A JP 2013-242324 A

  Although Patent Document 1 describes that the ECU controls the switch of the battery module independently, it does not describe cooperation with a BMS / BMU (Battery Management System / Battery Management Unit) which is a host device. That is, when an abnormality has occurred in the ECU itself, there is a possibility that the abnormality of the battery module cannot be detected.

  The technique disclosed in Patent Document 2 is to equalize the voltage between battery strings by controlling the switching of the voltage equalization circuit that reduces the voltage difference between the battery strings with the BMU. However, this is not a technique for monitoring and controlling the entire secondary battery module with BMS. In addition, when an abnormality or the like occurs in a BMU that is susceptible to noise such as an inverter, there is a problem that the system cannot be monitored and controlled and the system must be stopped.

  The technique shown in Patent Document 3 is intended to control and equalize voltage abnormality by ECU (Engine Control Unit) via BMU while monitoring the charging state of each secondary battery module by CMU (Cell Monitoring Unit). Similarly to the above, it is not a technique for monitoring and controlling the entire secondary battery module with the BMS while independently monitoring the secondary battery module with the CMU. In addition, when an abnormality or the like occurs in a BMU that is susceptible to noise such as a connected load or inverter, the system cannot be monitored and controlled, and the system must be stopped. .

  In the present invention, the ECU independently monitors the abnormality of each secondary battery module in which a plurality of secondary batteries are connected in series and parallel, and the entire module is monitored by the BMU, and the BMU functions. Provided a secondary battery system in which the entire module can be shifted to a safe state by disconnecting the module at its own discretion when the ECU is not present, etc., and can respond to an abnormality without stopping the operation of the entire system .

  A secondary battery system according to the present invention includes a secondary battery module group formed by connecting a plurality of secondary battery modules in which a plurality of secondary batteries are connected in series, and charging / discharging of the secondary battery system. A charge / discharge control unit that controls the individual battery, an individual switch that switches ON / OFF the connection between each secondary battery module of the secondary battery module group and the charge / discharge control unit, and each secondary battery module A current measuring means for measuring the current value, an ECU for receiving information on the current value of the current measuring means, and controlling on / off of the individual switch according to the state of the received current value, and the charge / discharge A main switch for turning ON / OFF the connection between the control unit and the secondary battery module group, and monitoring and controlling the entire system, and based on the information acquired from the ECU, the main switch In which and a BMS for performing the ON / OFF control.

  Thus, in the secondary battery system according to the present invention, a secondary battery module group formed by connecting a plurality of secondary battery modules in which a plurality of secondary batteries are connected in series, and a secondary battery. A charge / discharge control unit that controls charging / discharging of the system, an individual switch that switches ON / OFF of a connection between each secondary battery module of the secondary battery module group and the charge / discharge control unit, Current measurement means for measuring a current value for each secondary battery module, and an ECU that receives information on the current value of the current measurement means and controls ON / OFF of the individual switch according to the state of the received current value And a main switch for turning on / off the connection between the charge / discharge control unit and the secondary battery module group, and monitoring and controlling the entire system, and based on information acquired from the ECU In addition, since the BMS for performing ON / OFF control of the main switch is provided, the ECU and the BMS are double monitored while monitoring and controlling each secondary battery module independently in the ECU. The secondary battery system can be effectively protected.

  In the secondary battery system according to the present invention, when the ECU determines that the state of the current value is abnormal, the ECU turns off the individual switch corresponding to the secondary battery module in which the current is abnormal. The BMS receives information on the current abnormality of the secondary battery from the ECU, determines whether the system can be operated with a capacity excluding the secondary battery in which the current abnormality has occurred, If the operation can be continued, the main switch is turned on, and the recalculation necessary for operation is performed with the capacity excluding the secondary battery in which the current is abnormal.

  Thus, in the secondary battery system according to the present invention, when the ECU determines that the state of the current value is abnormal, the individual battery corresponding to the secondary battery module having the current abnormality is stored. The switch is turned off, and the BMS receives information on the current abnormality of the secondary battery from the ECU, and determines whether the system can be operated with a capacity excluding the secondary battery in which the current abnormality has occurred. If it is possible to continue the operation, turn on the main switch, and stop the system to recalculate the parameters necessary for operation with the capacity excluding the secondary battery that has become abnormal in current. There is an effect that it becomes possible to repair and maintain a secondary battery module that has an abnormality while maintaining its operating state.

  In the secondary battery system according to the present invention, when it is determined that the operation of the system cannot be continued when the BMS excludes the secondary battery having the current abnormality, the BMS The system is stopped by turning off the switch.

  As described above, in the secondary battery system according to the present invention, when it is determined that the operation of the system cannot be continued when the BMS excludes the secondary battery having the current abnormality, Since the BMS stops the system by turning off the main switch, there is an effect that the system can be stopped and protected when the system cannot be operated.

  The secondary battery system according to the present invention includes a charge / discharge changeover switch for switching between charge and discharge for each secondary battery module, and a reverse direction between the secondary battery module and the charge / discharge control unit. Are connected in parallel corresponding to the charge / discharge switch.

  Thus, in the secondary battery system according to the present invention, for each secondary battery module, between the charge / discharge changeover switch for switching between charge and discharge, and between the secondary battery module and the charge / discharge control unit. Since diodes that are opposite to each other are connected in parallel corresponding to the charge / discharge switching switch, even if an abnormality occurs in a certain secondary battery module, current wraparound is prevented, There exists an effect that a battery module can be protected.

1 is a system configuration diagram of a secondary battery system according to a first embodiment. It is a functional block diagram which shows the structure of BMS. It is a flowchart which shows the operation | movement in the operation state of the secondary battery system which concerns on 1st Embodiment. It is a system block diagram of the secondary battery system which concerns on 2nd Embodiment. It is a figure which shows the process in the case of preventing the inflow of the electric current to a secondary battery module.

  Embodiments of the present invention will be described below. Also, the same reference numerals are given to the same elements throughout the present embodiment.

(First embodiment of the present invention)
The secondary battery system according to the present embodiment will be described with reference to FIGS. The secondary battery system according to this embodiment includes a plurality of (for example, several to several thousand) secondary battery modules in which a plurality of (for example, about 2 to 8 cells) secondary battery cells are connected in series. A secondary battery module group is formed by connection, and an individual switch for switching ON / OFF of connection between each secondary battery module of the secondary battery module group and a charge / discharge control unit including an inverter or the like is provided. The ECU performs ON / OFF control based on the current value measured for each secondary battery module. Moreover, it has the main switch which turns ON / OFF the connection between a charging / discharging control part and a secondary battery module group collectively, and BMS turns ON / OFF of a main switch based on the information acquired from ECU. Control is performed.

  FIG. 1 is a system configuration diagram of the secondary battery system according to the present embodiment. The secondary battery system 1 includes a charge / discharge control unit 2 having a discharge control unit 2a connected to a load at the time of discharging and a charge control unit 2b connected to a power source at the time of charging, and charging / discharging of the secondary battery system 1. A charge / discharge switch 3 for switching, a main switch 4 for switching ON / OFF between the entire secondary battery and the charge / discharge control unit 2, and a secondary battery module 6 formed by connecting a plurality of cells 5 in series. CT7 for measuring the current value of the secondary battery module 6, an individual switch 8 for turning on / off the connection with the charge / discharge control unit 2 for each secondary battery module 6, and an individual switch based on the value of CT7 ECU 9 that performs ON / OFF control of 8 and BMS 10 that monitors and controls the entire system and controls ON / OFF of the main switch 4 based on information acquired from the EUC 9. That.

  At the time of charging, the charging / discharging changeover switch 3 is connected to the charging control unit 2b by the control of the BMS 10, and the secondary battery module 6 is charged. At the time of discharging, the charge / discharge changeover switch 3 is connected to the discharge controller 2a, and the power of the secondary battery module 6 is supplied to the load. The ECU 9 monitors the state of the secondary battery module 6 corresponding to each secondary battery module 6 and transmits it to the BMS 10. Conventionally, the BMS 10 controls the main switch 4 so as to disconnect the secondary battery module 6 from the secondary battery system 1 when an abnormality is detected from the ECU 9. In this case, only one secondary switch is provided. Even if the battery module 6 has an abnormality, the entire system stops.

  Therefore, in the present embodiment, the current value of each secondary battery module 6 is measured by CT 7 and ECU 9 determines whether the measured current value is normal or abnormal. If it is determined that the current value is abnormal, information indicating that is transmitted to the BMS 10 and the individual switch 8 corresponding to the secondary battery module 6 in which the current value is abnormal is controlled to be OFF. By turning off the individual switch 8, it is possible to disconnect only the secondary battery module 6 in which an abnormality has occurred in the current value from the system and to maintain the system operation with other normal secondary battery modules 6. .

  In addition, the BMS 10 that has received the current value abnormality information from the ECU 9 performs recalculation of the operation in a state where the secondary battery module 6 in which the abnormality has occurred is disconnected from the system, and determines whether the system operation can be continued. To do. If system operation can be continued, reset the parameters and continue operation. If the operation of the system cannot be continued, the main switch 4 is turned off and the entire system is stopped.

  FIG. 2 is a functional block diagram showing the configuration of the BMS 10. The BMS 10 has an input unit 21 for inputting information from the ECU 9, and the capacity and supply required when operating the secondary battery module 6 in which an abnormality has occurred in a state disconnected from the system based on the input information. A recalculation unit 22 that recalculates the capacity, a continuation determination unit 23 that determines whether the operation can be continued based on the recalculated result, and a setting information storage when it is determined that the operation can be continued The parameter resetting unit 24 that sets and updates the parameters after recalculation in the unit 26 and the main switch 4 is turned off to disconnect all the secondary battery modules 6 from the system when it is determined that the operation cannot be continued. And a switch control unit 25 that performs control.

  With such a configuration, even if the ECU 9 disconnects the secondary battery module 6 whose current value is abnormal as determined by the ECU 9 from the system, it is determined whether or not the entire system can be operated continuously. If it can be continued, the operating state can be maintained without stopping the system. Further, when the system cannot be operated, the system can be stopped based on the judgment of the BMS 10, and therefore the system can be protected while ensuring safety by multiple checks between the ECU 9 and the BMS 10.

  Next, the operation of the secondary battery system according to this embodiment will be described. FIG. 3 is a flowchart showing the operation in the operating state of the secondary battery system according to the present embodiment. When the operation of the secondary battery system 1 is started, the current value of the secondary battery module 6 is measured at CT7, and the information is transmitted to the ECU 9 (S1). In the ECU 9, a threshold value preset in the memory is compared with the measured current value by the arithmetic function of the CPU, and it is determined whether or not the measured current value is abnormal (S2). If it is determined that there is no abnormality, the process returns to step S1 and the current value measurement is continued. When it is determined that there is an abnormality, the individual switch 8 is controlled to be turned OFF by an instruction from the ECU 9, and only the secondary battery module 6 that is determined to be abnormal is disconnected from the secondary battery system 1 (S3).

  The secondary battery module 6 is disconnected, and the ECU 9 transmits information on the current value abnormality of the secondary battery module 6 to the BMS 10 (S4). The BMS 10 identifies the secondary battery module 6 separated from the secondary battery system 1 based on the received current value abnormality information, and other secondary battery modules 6 excluding the separated secondary battery module 6 Whether the operation of the secondary battery system 1 can be continued is recalculated (S5). As a result of the recalculation, the BMS 10 determines whether or not the operation of the secondary battery system 1 can be continued (S6). If it is determined that the operation can be continued, the parameters obtained by recalculation are used. The setting information is updated (S7), and the operation returns to step S1 to continue operation. Then, the secondary battery module 6 in which an abnormality has occurred is repaired and maintained while the operation of the secondary battery system 1 is maintained. As a result of the recalculation, when the BMS 10 determines that the operation of the secondary battery system 1 cannot be continued, the BMS 10 controls the main switch 4 to be OFF (S8), and all the secondary battery modules 6 are secondary batteries. Disconnect from the system 1 and stop the secondary battery system 1.

  As described above, in the secondary battery system according to the present embodiment, the ECU 9 monitors and controls each of the secondary battery modules 6 independently, and performs double monitoring of the ECU 9 and the BMS 10, thereby The secondary battery system 1 can be effectively protected.

  Further, it is determined whether or not the secondary battery system 1 can be operated with the capacity excluding the secondary battery module 6 in which the current is abnormal. If the operation can be continued, the main switch 4 is turned on, In order to recalculate the parameters necessary for operation with the capacity excluding the secondary battery module 6 that has become abnormal, the secondary battery system 1 was abnormal while maintaining the operating state without being stopped. The secondary battery module 6 can be repaired and maintained.

  Further, when it is determined that the operation of the secondary battery system 1 cannot be continued when the secondary battery module 6 in which the BMS 10 has an abnormal current is excluded, the BMS 10 turns off the main switch 4 and determines the system. Therefore, when the operation of the secondary battery system 1 is impossible, the secondary battery system 1 can be stopped and protected.

(Second embodiment of the present invention)
The secondary battery system according to the present embodiment will be described with reference to FIGS. 4 and 5. In the secondary battery system according to the present embodiment, for each secondary battery module, diodes in opposite directions are connected in parallel between the secondary battery module and the charge / discharge control unit. . In addition, in this embodiment, the description which overlaps the said 1st Embodiment is abbreviate | omitted.

  FIG. 4 is a system configuration diagram of the secondary battery system according to the present embodiment. The difference from FIG. 1 in the first embodiment is that the charge / discharge changeover switch 3 is connected to the terminal 41a to be connected during charging, the charge / discharge control unit 2 side is the anode, and the secondary battery module 6 side is the cathode. Diode 42a connected in parallel with the diode 42a, the charge / discharge changeover switch 3 is connected to the terminal 41b side to be connected during discharge, the charge / discharge control unit 2 side is the cathode, and the secondary battery module 6 side is the anode And a diode 42b.

  The charging / discharging changeover switch 3 determines whether the process to be performed from now on is charging or discharging by the BMS 10 and is switched by the control of the BMS 10. That is, when connected to an external power source such as a grid or a solar panel, the BMS 10 determines that the charging process is being performed, and connects the charge / discharge switch 3 to the terminal 41a side. At this time, since there is the diode 42a, a current flows from the charge / discharge control unit 2 side to the secondary battery module 6 but does not flow in the opposite direction. On the other hand, when connected to an external load, it is determined that the BMS 10 is in a discharge process, and the charge / discharge changeover switch 3 is connected to the terminal 41b side. At this time, since there is the diode 42b, a current flows from the secondary battery module 6 side to the charge / discharge control unit 2 but does not flow in the opposite direction. That is, by controlling the charge / discharge changeover switch 3, processing relating to charge / discharge can be performed without any problem.

  When an abnormality occurs in a certain secondary battery module 6, it is possible to prevent the current from flowing into the secondary battery module 6 where the abnormality has occurred by providing the diodes 42a and 42b. FIG. 5 is a diagram illustrating a process in the case of preventing a current from flowing into the secondary battery module. FIG. 5A shows processing during charging, and FIG. 5B shows processing during discharging. As shown in FIG. 5A, since the secondary battery module 6 side is the cathode and the charge / discharge control unit 2 side is the anode during charging, for example, there is something abnormal in the secondary battery module 6 in the middle of FIG. Even when the voltage is lowered due to the occurrence of the current, the diode 42a is arranged, so that the current from the other normal secondary battery module 6 to the secondary battery module in which the abnormality is in the middle occurs. There is no inflow.

  Further, as shown in FIG. 5B, since the secondary battery module 6 side is an anode and the charge / discharge control unit 2 side is a cathode at the time of discharging, for example, the secondary battery module 6 in the middle of FIG. Even when an abnormality occurs and the voltage drops, the diode 42b is arranged so that another normal secondary battery module 6 can be connected to the secondary battery module in which the middle abnormality has occurred. There is no current flow.

  In this way, by having the switch 41 and the diodes 42a and 42b according to the charge / discharge, even if an abnormality occurs in the secondary battery module, current wraparound is prevented and the secondary battery module is protected. can do.

  A thyristor may be provided in place of the diodes 42a and 42b. That is, in a normal state, the thyristor is turned on to conduct current, and when an abnormality occurs, the thyristor is turned off by control of the ECU 9 to stop the conduction state and protect the secondary battery module 6. Is possible.

DESCRIPTION OF SYMBOLS 1 Secondary battery system 2 Charge / discharge control part 2a Discharge control part 2b Charge control part 3 Charge / discharge switching switch 4 Main switch 5 Cell 6 Secondary battery module 7 CT
8 Individual switch 9 ECU
10 BMS
DESCRIPTION OF SYMBOLS 21 Input part 22 Recalculation part 23 Continuation determination part 24 Parameter resetting part 25 Switch control part 26 Setting information storage part 41a, 41b Terminal 42a, 42b Diode

Claims (4)

A group of secondary battery modules formed by connecting in parallel a plurality of secondary battery modules in which a plurality of secondary batteries are connected in series;
A charge / discharge control unit for controlling charge / discharge of the secondary battery system;
An individual switch for switching ON / OFF of a connection between each secondary battery module of the secondary battery module group and the charge / discharge control unit;
Current measuring means for measuring a current value for each of the secondary battery modules;
An ECU that receives information on the current value of the current measuring means, and controls ON / OFF of the individual switch according to the state of the received current value;
A main switch for turning ON / OFF the connection between the charge / discharge control unit and the secondary battery module group;
A secondary battery system comprising: a BMS that monitors and controls the entire system and performs ON / OFF control of the main switch based on information acquired from the ECU. The secondary battery system according to claim 1,
When the ECU determines that the state of the current value is abnormal, the ECU turns off the individual switch corresponding to the secondary battery module in which the current is abnormal,
The BMS receives information on the current abnormality of the secondary battery from the ECU, determines whether the system can be operated with a capacity excluding the secondary battery having the current abnormality, If the continuation is possible, the main battery switch is turned on, and recalculation necessary for operation is performed with a capacity excluding the secondary battery in which the current is abnormal. The secondary battery system according to claim 2,
When it is determined that the operation of the system cannot be continued when the BMS excludes the secondary battery having the current abnormality, the BMS turns off the main switch and stops the system. A secondary battery system. The secondary battery system according to any one of claims 1 to 3,
For each of the secondary battery modules, a charge / discharge switch for switching between charging and discharging,
A secondary battery system, wherein diodes that are opposite to each other are connected in parallel between the secondary battery module and the charge / discharge control unit in correspondence with the charge / discharge switch.

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