Charging and discharging device

Abstract

To provide a charge and discharge device capable of individually controlling BMU of a plurality of battery modules by a single communication control device even when the plurality of battery modules of the same specification mounted on a vehicle are used.SOLUTION: A charge and discharge device has a plurality of battery modules 4, a connection path 5, an electric load 3, a first switch 6, a communication control device 8, and a generation device 2. The battery module 4 has a storage battery 41 and a BMU 42. The BMU 42 of each battery module 4 has a common CAN_ID, and a storing part 81 storing a voltage value of the storage battery 41 for each battery module 4 is provided on the communication control device 8. The communication control device 8 is configured so as to control each BMU 42 by using the common CAN_ID. When all of the first switches 6 of the plurality of battery modules 4 are in an OFF state, the first switch 6 of the battery module 4 having the storage battery 41 whose voltage value is lowest among the voltage values stored in the storing part 81 is switched to an ON state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a charge / discharge device. [Background technology]

[0002] Patent Document 1 discloses an energy storage system that constitutes an independent drive system for supplying power to a mobile phone base station (load) installed in a remote area where commercial power cannot be drawn, such as a mountainous region. This energy storage system includes multiple battery units, a power generation unit, a power conversion unit, a charging power supply unit, and a control unit.

[0003] In this energy storage system, when the battery unit to be discharged is switched from the first battery unit to the second battery unit, a backup is provided by the third battery unit, and even if discharging from the second battery unit fails, power is supplied from the third battery unit, thereby avoiding a halt to the operation of the load. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-135533 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a reused battery module that was mounted on a vehicle is used as a battery unit of the power storage system as described in Patent Document 1, the following problems arise.

[0006] The battery module installed in the vehicle has a controller (hereinafter referred to as "BMU (Battery Management Unit)") that manages the voltage value of the storage battery for each cell. This BMU uses the CAN (Controller Area Network) standard for communicating with other controllers.

[0007] In CAN, an ID is assigned to each signal, but when multiple reused battery modules with the same specifications are used, the IDs used by the BMUs of all of these battery modules will be the same. For this reason, if one communication control device is to communicate with the BMUs of multiple battery modules with the same specifications through CAN, signals will overlap and it will be impossible to control multiple BMUs individually.

[0008] In this case, for example, if a communications control device is provided for each BMU, it will be possible to individually control the BMUs of multiple battery modules with the same specifications. However, since a communications control device is required for each battery module, costs will be high even if inexpensive reused parts are used.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a charging / discharging device that can individually control the BMUs of multiple battery modules with a single communication control device, even when multiple battery modules of the same specifications that were installed in a vehicle are used. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention provides a system including a plurality of battery modules, a connection path to which the plurality of battery modules are connected in parallel, an electrical load connected to the connection path, a switch capable of switching between an on state to connect the battery module and the connection path or an off state to disconnect the battery module, a communication control device connected to the connection path and controlling the switching of the switch, and a power supply device connected to the connection path so as to be able to supply power to the plurality of battery modules and the communication control device, wherein the battery modules include a storage battery and a BMU that manages the state of the storage battery, and the BMU of each of the plurality of battery modules has a common identification signal, the communication control device is provided with a memory unit that stores a voltage value of the storage battery for each battery module, and the communication control device is configured to control each BMU using the common identification signal, and when all of the switches of the plurality of battery modules are in an off state, the switch of the battery module having the storage battery with the lowest voltage value among the voltage values ​​stored in the memory unit is switched to an on state. Effect of the Invention

[0011] According to the present invention, a charging / discharging device can be provided that can individually control the BMUs of multiple battery modules with a single communication control device, even if multiple battery modules of the same specifications that were installed in a vehicle are used. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a charge / discharge device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of each voltage value stored in the storage unit of the charge / discharge device according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic diagram of a charge / discharge device according to a second embodiment of the present invention. [Figure 4] FIG. 4 is an example of a timing chart showing switching of the battery modules in the charge / discharge device according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A charging / discharging device according to an embodiment of the present invention includes a plurality of battery modules, a connection path to which the plurality of battery modules are connected in parallel, an electric load connected to the connection path, a switch capable of switching between an ON state for connecting the battery modules to the connection path and an OFF state for disconnecting the battery modules from the connection path, a communication control device connected to the connection path and controlling the switching of the switch, and a power supply device connected to the connection path so as to be able to supply power to the plurality of battery modules and the communication control device, the battery modules each have a storage battery and a BMU for managing the state of the storage battery, the BMU of each of the plurality of battery modules has a common identification signal, the communication control device is provided with a storage unit for storing the voltage value of the storage battery for each battery module, the communication control device is configured to control each BMU using the common identification signal, and when all the switches of the plurality of battery modules are in the OFF state, the switch of the battery module having the storage battery with the lowest voltage value among the voltage values ​​stored in the storage unit is switched to the ON state. As a result, the charging / discharging device according to the embodiment of the present invention can individually control the BMUs of the plurality of battery modules with one communication control device even when a plurality of battery modules with the same specifications that were installed in a vehicle are used. EXAMPLES

[0014] Hereinafter, a charging / discharging device according to an embodiment of the present invention will be described with reference to the drawings.

[0015] (First embodiment) As shown in FIG. 1, the charging / discharging device 1 of the first embodiment includes a power generation device 2 as a power supply device, an electrical load 3, a plurality of battery modules 4, a connection path 5, a first switch 6 as a switch, a second switch 7, and a communication control device 8.

[0016] The charging / discharging device 1 according to this embodiment is provided with 1 to n battery modules 4. In this embodiment, the battery modules 4 are indicated as battery modules 4(1) to 4(n) in order to distinguish between them. When indicating one battery module without specifying which of the battery modules 4(1) to 4(n) is selected, the battery module is simply referred to as "battery module 4."

[0017] The power generation device 2 is connected to a connection path 5 so as to be able to supply power to a plurality of battery modules 4 and a communication control device 8.

[0018] The power generation device 2 is configured by a power generation device that generates power using renewable energy, such as a solar power generation device, a wind power generation device, etc. Power generation devices that generate power using renewable energy are not limited to solar power generation devices and wind power generation devices, and power generation devices that use renewable energy such as hydraulic power, geothermal power, and biomass can also be used.

[0019] The electric load 3 is configured by a device having a light-emitting body as a load, such as a light, an electric bulletin board, etc. The electric load 3 is not limited to a device having a light-emitting body as a load.

[0020] The battery modules 4(1) to 4(n) are connected in parallel to one another via a connection path 5. Each battery module 4 has a storage battery 41 and a BMU (Battery Management Unit) 42. The battery modules 4 of this embodiment are reused battery modules that were installed in a vehicle.

[0021] In this embodiment, in order to distinguish which storage battery 41 and BMU 42 of the battery modules 4(1) to 4(n) they correspond to, the storage batteries 41 and BMUs 42 corresponding to the battery modules 4(1) to 4(n) are indicated as storage batteries 41(1) to 41(n) and BMUs 42(1) to 42(n). When indicating one storage battery and one BMU for the storage batteries 41(1) to 41(n) and BMUs 42(1) to 42(n) without specifying which of the battery modules 4(1) to 4(n) they belong to, they are simply referred to as "storage battery 41" and "BMU 42," respectively.

[0022] The storage battery 41 is configured by a chargeable and dischargeable secondary battery such as a lithium ion battery, etc. As the storage battery 41, for example, a lithium ion battery that has been reused from a vehicle is used.

[0023] The BMU 42 monitors and manages the state of the storage battery 41, such as the voltage value and remaining capacity (SOC: state of charge) of the storage battery 41. The BMU 42 calculates the SOC based on the charge / discharge current of the storage battery 41.

[0024] The BMU 42 is connected to the communication control device 8 and is configured to be able to transmit various information such as the voltage value and SOC of the storage battery 41 to the communication control device 8. The BMU 42 uses CAN (Controller Area Network) as a communication standard for communicating with the communication control device 8.

[0025] Each of the BMUs 42(1) to 42(n) has a CAN_ID as an identification signal for identifying the device itself when communicating with the communication control device 8. In this embodiment, the CAN_IDs of the BMUs 42(1) to 42(n) are common to each other. That is, each of the BMUs 42(1) to 42(n) uses a common CAN_ID.

[0026] This is because the CAN_IDs of the BMUs of battery modules of the same specifications mounted on a vehicle are the same, and the charge / discharge device 1 of this embodiment uses a plurality of reused battery modules of the same specifications.

[0027] The first switch 6 is provided between the battery module 4 and the connection path 5, and is a switch that can be switched between an ON state in which the battery module 4 and the connection path 5 are connected, and an OFF state in which the battery module 4 and the connection path 5 are disconnected.

[0028] In this embodiment, in order to distinguish the first switches 6 of the battery modules 4(1) to 4(n), the first switches 6 corresponding to the battery modules 4(1) to 4(n) are indicated as first switches 6(1) to 6(n). When indicating one first switch without specifying which of the battery modules 4(1) to 4(n) the first switches 6(1) to 6(n) belong to, the first switches are simply referred to as "first switch 6."

[0029] The switching of the first switch 6 between the on state and the off state is controlled by a communication control device 8.

[0030] Battery modules 4(1) to 4(n) are connected in parallel to the connection path 5. A second switch 7 is connected to one end of the connection path 5.

[0031] The second switch 7 is provided between the connection path 5 and the power generation device 2 and the electrical load 3, and is a switch that can be switched between an on state in which the connection path 5 connects the power generation device 2 or the electrical load 3, and an off state in which the connection path 5 is disconnected.

[0032] That is, the second switch 7 can be switched between either an on state, a power generation on state in which the connection path 5 is connected to the power generation device 2, or a discharge on state in which the connection path 5 is connected to the electrical load 3, and an off state in which the connection path 5 is not connected to either the power generation device 2 or the electrical load 3.

[0033] The switching of the second switch 7 between the power generation on state, the discharge on state, and the off state is controlled by the communication control device 8. In a state in which the power supply of the communication control device 8 is not yet turned on, such as at the initial startup of the charging / discharging device 1, it is preferable that the second switch 7 is switched to the power generation on state in order to ensure power for starting up the charging / discharging device 1.

[0034] The communication control device 8 is composed of a computer unit having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input port, and an output port. The ROM of the computer unit stores various constants and other data as well as a program for causing the computer unit to function as the communication control device 8. That is, the CPU uses the RAM as a working area to execute the program stored in the ROM, causing the computer unit to function as the communication control device 8 in this embodiment.

[0035] The communication control device 8 is connected to the connection path 5, and is supplied with power from the power generation device 2 or at least one of the battery modules 4(1) to 4(n) via the connection path 5. The communication control device 8 controls switching of the first switch 6 and the second switch 7 between the on state and the off state.

[0036] Various sensors 9 are connected to the communication control device 8. In this embodiment, the various sensors 9 are connected as necessary depending on the type of power generation device 2 and the type of electric load 3, and for example, sensors capable of detecting changes in the external environment, such as a wind sensor, an illuminance sensor, and a temperature sensor, are connected. Furthermore, when the electric load 3 is a light, the communication control device 8 may include a timer that manages the lighting duration and lighting time.

[0037] In this embodiment, the communication control device 8 is provided with a storage unit 81. The storage unit 81 may be configured, for example, by the above-mentioned RAM, or may be configured by a storage device other than the above-mentioned RAM.

[0038] The storage unit 81 of the communication control device 8 is configured to store the voltage value of the storage battery 41 for each battery module 4. Specifically, as shown in Fig. 2, the storage unit 81 stores the voltage values ​​of the storage batteries 41(1) to 41(n) in association with each of the battery modules 4(1) to 4(n) for a common CAN_ID.

[0039] The voltage value stored in the memory unit 81 is, for example, a voltage value measured at the timing when the first switch 6 is switched to the OFF state. That is, at the timing when the communication control device 8 sends an instruction to the first switch 6 to switch any one of the first switches 6(1) to 6(n) to the OFF state, the communication control device 8 acquires a voltage value from the BMU 42 of the battery module 4 corresponding to the first switch 6 to which the instruction is sent.

[0040] The communication control device 8 controls each of the BMUs 42(1) to 42(n) using a common CAN_ID. Therefore, when the communication control device 8 tries to control the BMUs 42(1) to 42(n), the CAN_IDs overlap, and the communication control device 8 cannot control each of the BMUs 42(1) to 42(n) individually. In this case, the communication control device 8 cannot distinguish which storage battery 41 the voltage value transmitted from each BMU 42 belongs to, and as a result, it cannot determine which of the first switches 6(1) to 6(n) should be switched.

[0041] Therefore, in this embodiment, the communication control device 8 employs the following configuration so that it can individually control each of BMUs 42(1) to 42(n) even when a common CAN_ID is used for BMUs 42(1) to 42(n).

[0042] That is, when all of the first switches 6 of the battery modules 4(1) to 4(n) are in the OFF state, the communication control device 8 switches to the ON state the first switch 6 of the battery module 4 having the storage battery 41 having the lowest voltage value among the voltage values ​​of the storage batteries 41(1) to 41(n) stored in the memory unit 81.

[0043] As described above, the charge / discharge device 1 according to this embodiment is configured so that the voltage value of each storage battery 41 for each battery module 4 is stored in the memory unit 81 of the communication control device 8.

[0044] With this configuration, the charging / discharging device 1 of this embodiment can distinguish and grasp the voltage values ​​of each storage battery 41, even if a common CAN_ID is used for each BMU 42 of the battery modules 4(1) to 4(n), because the voltage values ​​of each storage battery 41 are stored in the memory unit 81.

[0045] Furthermore, the charging / discharging device 1 of this embodiment is configured to switch to the on state the first switch 6 of the battery module 4 having the storage battery 41 having the lowest voltage value among the voltage values ​​of the storage batteries 41(1) to 41(n) stored in the memory unit 81 when all the first switches 6 of the battery modules 4(1) to 4(n) are in the off state.

[0046] With this configuration, the charging / discharging device 1 according to this embodiment is able to perform one-to-one communication between the communication control device 8 and the BMU 42 while preferentially charging the battery module 4 having a storage battery 41 with a low voltage value over other battery modules 4. As a result, even when multiple reused battery modules 4 with the same specifications that were mounted on a vehicle are used, the single communication control device 8 can individually control the BMUs 42 of these multiple battery modules 4.

[0047] Furthermore, the charging / discharging device 1 of this embodiment can control multiple BMUs 42 with one communication control device 8 without the need to change specifications, such as changing the CAN_ID for each BMU 42, which can contribute to cost reduction and take advantage of the advantages of using reused battery modules 4.

[0048] In addition, the charging / discharging device 1 of this embodiment is provided with a second switch 7 that is provided between the connection path 5 and the power generation device 2 and the electrical load 3 and is capable of switching between an on state that connects the connection path 5 to the power generation device 2 or the electrical load 3, and an off state that disconnects the connection path 5 from the power generation device 2 or the electrical load 3.

[0049] With this configuration, the charging / discharging device 1 according to this embodiment can, for example, switch the power supply source to the electric load 3 between the power generation device 2 and the battery module 4 as necessary, and can ensure the power supply to the communication control device 8 in a state where there is no charging from the power generation device 2 and no discharging to the electric load 3. This allows the charging / discharging device 1 according to this embodiment to function as an independent charging / discharging device.

[0050] Moreover, the charging / discharging device 1 according to this embodiment is configured by a power generating device in which the power generating device 2 generates power by utilizing renewable energy. This allows the charging / discharging device 1 according to this embodiment to be independently installed outdoors.

[0051] Moreover, the charging / discharging device 1 according to this embodiment is configured by a device in which the electric load 3 has a light-emitting body as a load. This allows the charging / discharging device 1 according to this embodiment to be used for lighting or an electric bulletin board that is independently installed outdoors.

[0052] (Second Example) Next, a charging / discharging device 101 according to a second embodiment will be described with reference to FIGS.

[0053] As shown in FIG. 3, a charging / discharging device 101 of this embodiment includes a plurality of battery module groups 104, each of which is made up of a plurality of battery modules 4, a first switch 6, and a communication control device 8 in the first embodiment.

[0054] In this embodiment, two battery module groups 104 are provided, and in order to distinguish between them, one is indicated as battery module group 104A and the other is indicated as battery module group 104B. In this embodiment, an example in which two battery module groups 104 are provided will be described, but a configuration in which three or more battery module groups 104 are provided may also be used.

[0055] In this embodiment, in order to clarify which of the two battery module groups 104 the battery module 4, the first switch 6, and the communication control device 8 belong to, those belonging to the battery module group 104A are distinguished by adding "A" to their reference numerals, and those belonging to the battery module group 104B are distinguished by adding "B" to their reference numerals. Similarly, the storage battery 41, the BMU 42, and the memory unit 81 are distinguished by adding "A" or "B" to their reference numerals.

[0056] In the charging / discharging device 101 of this embodiment, the communication control device 8A and the communication control device 8B are connected to enable two-way communication. The memory unit 81A of the communication control device 8A stores the voltage values ​​of each of the battery modules 4 belonging to the battery module group 104A. The memory unit 81B of the communication control device 8B stores the voltage values ​​of each of the battery modules 4 belonging to the battery module group 104B.

[0057] In the charging / discharging device 101 of this embodiment configured as described above, when charging the battery module 4 with power supplied from the power generation device 2, the communication control device 8A and the communication control device 8B switch to the on state the first switch 6 of the battery module 4 having the storage battery 41 with the lowest voltage value among the voltage values ​​of each battery module 4 stored in the memory unit 81A and the memory unit 81B.

[0058] For example, the communication control device 8A and the communication control device 8B compare the lowest voltage value among the voltage values ​​of each storage battery 41 stored in the memory unit 81A with the lowest voltage value among the voltage values ​​of each storage battery 41 stored in the memory unit 81B, and switch the first switch 6 of the battery module 4 having the storage battery 41 with the lower voltage value to the on state.

[0059] In addition, when the supply voltage from the power generation device 2 is less than the voltage required for the operation of the BMU 42 and the communication control device 8 (hereinafter referred to as the "operating voltage"), the charging / discharging device 101 of this embodiment supplies power to the BMU 42 and the communication control device 8 from the battery module 4 whose first switch 6 is currently in the on state.

[0060] At this time, if the voltage value of the storage battery 41 of the battery module 4 with the first switch 6 in the on state falls below a predetermined value obtained by adding a predetermined margin to the above operating voltage, it may not be possible to maintain the operating voltage of the BMU 42 and the communication control device 8. In other words, it may not be possible to supply the BMU 42 and the communication control device 8 with the power necessary for their operation.

[0061] Therefore, in the charging / discharging device 101 of this embodiment, when the supply voltage from the power generation device 2 is less than the operating voltage and the voltage value of the storage battery 41 currently connected to the connection path 5 via the first switch 6 in the ON state is less than a predetermined value, the charging / discharging device 101 switches the storage battery 41 connected to the connection path 5 to a storage battery 41 having a voltage value equal to or greater than the predetermined value. Specifically, the first switch 6 currently in the ON state is switched to the OFF state, and the first switch 6 corresponding to the battery module 4 having the storage battery 41 to be switched to is switched to the ON state.

[0062] Here, when switching the storage battery 41 between the battery module group 104A and the battery module group 104B, i.e., when switching from one of the storage batteries 41 in the battery module group 104A to one of the storage batteries 41 in the battery module group 104B, or vice versa, the communication control device 8 of the battery module group 104 having the storage battery 41 before switching will be different from the communication control device 8 of the battery module group 104 having the storage battery 41 to which the switching is to be made. Therefore, there is no duplication of CAN_IDs in the same communication control device 8.

[0063] Therefore, when switching the storage battery 41 between the battery module group 104A and the battery module group 104B, for example, the first switch 6 currently in the on state is switched to the off state and the first switch 6 corresponding to the battery module having the storage battery 41 to be switched to is switched to the on state simultaneously, or the first switch 6 corresponding to the battery module having the storage battery 41 to be switched to the on state is first switched to the off state.

[0064] In contrast, when switching a battery module 4 in which the first switch 6 is in the on state within one of the battery module groups 104A, 104B, i.e., when switching a storage battery 41 within the same battery module group, it is desirable to first switch the first switch 6 currently in the on state to the off state, and then switch the first switch 6 corresponding to the battery module having the storage battery 41 to be switched to the on state, so as to prevent duplication of CAN_IDs in the communication control device 8.

[0065] However, in this case, if the first switch 6 that is currently in the on state is switched to the off state, the power supply to the communication control device 8 will be cut off, and the first switch 6 corresponding to the battery module having the storage battery 41 to be switched to cannot be switched to the on state.

[0066] Therefore, in this embodiment, when switching a battery module 4 in one of the battery module groups 104A, 104B in which the first switch 6 is in the on state, the storage battery 41 of one of the battery modules 4 in the other battery module groups is connected to the connection path 5 until the switching of the battery module 4 in that one battery module group is completed, so as to not interrupt the power supply to the communication control device 8.

[0067] Specifically, when switching a battery module 4 in one battery module group whose first switch 6 is in the on state, the first switch 6 of one of the battery modules 4 in the other battery module groups is first switched to the on state, and then the battery module 4 in the one battery module group whose first switch 6 is in the on state is switched.

[0068] After the switching of the battery modules 4 in the one battery module group has been performed, the first switches 6 that have been switched to the ON state in the other battery module groups are switched to the OFF state.

[0069] An example of switching the storage batteries 41 within the same battery module group will be described with reference to FIG.

[0070] FIG. 4 is a timing chart showing an example in which the battery module in which the first switch 6 is turned on in the same battery module group 104A is switched from battery module 4A(1) to battery module 4A(2).

[0071] As shown in FIG. 4, before time t1, under conditions in which the supply voltage from the power generation device 2 is lower than the operating voltage of the BMU 42 and the communication control device 8, the first switch 6A(1) corresponding to the battery module 4A(1) is turned on, and power is supplied from the battery module 4A(1) belonging to the battery module group 104A to the BMU 42A(1) and the communication control device 8A.

[0072] Thereafter, at time t1, when the voltage value of the storage battery 41 of the battery module 4A(1) falls below a predetermined value, the first switch 6B(1) corresponding to the battery module 4B(1) belonging to the battery module group 104B is switched to the on state.

[0073] After that, at time t2, the first switch 6A(1) corresponding to the battery module 4A(1) is switched to the OFF state. This temporarily cuts off the connection between the battery module group 104A and the connection path 5. At this time, the first switch 6B(1) corresponding to the battery module 4B(1) has already been switched to the ON state, so the battery module group 104B is connected to the connection path 5. Therefore, even while the connection between the battery module group 104A and the connection path 5 is temporarily cut off, the power supply to the communication control device 8 is maintained.

[0074] After that, at time t3, the first switch 6A(2) corresponding to the battery module 4A(2) is switched to the on state, whereby the battery module group 104A is connected to the connection path 5, and power can be supplied from the battery module group 104A to the communication control device 8.

[0075] After that, at time t4, the first switch 6B(1) corresponding to the battery module 4B(1) is switched to the OFF state.

[0076] In this manner, in the example shown in FIG. 4, while the first switch 6B(1) corresponding to the battery module 4B(1) is in the on state, the battery module 4A connected to the connection path 5 within the battery module group 104A is switched, so that the voltage value of the connection path 5 is maintained at or above the operating voltage even during the switching.

[0077] As described above, the charging / discharging device 1 of this embodiment is configured such that when the supply voltage from the power generation device 2 is lower than the operating voltage of the BMU 42 and the communication control device 8, when switching a battery module 4 in a certain battery module group whose first switch 6 is in the on state, the first switch 6 of any battery module 4 in the other battery module groups is first switched to the on state, and then the battery module 4 in the certain battery module group whose first switch 6 is in the on state is switched.

[0078] With this configuration, the charging / discharging device 1 of this embodiment can switch the battery module 4 whose first switch 6 is in the on state within one battery module group while maintaining the operating voltage of the BMU 42 and the communication control device 8, even if the supply voltage from the power generation device 2 is insufficient.

[0079] Furthermore, the charging / discharging device 1 of this embodiment is configured such that after switching of the battery modules 4 in one battery module group is performed, the first switches 6 that have been switched to the on state in other battery module groups are switched to the off state.

[0080] With this configuration, the charge / discharge device 1 according to this embodiment can prevent unnecessary discharge and reduce power consumption.

[0081] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made thereto without departing from the scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0082] 1, 101 Charging and discharging equipment 2. Power generation equipment (power supply equipment) 3 Electrical Load 4 Battery Module 5. Connecting Roads 6. First Switch (Switch) 7 Second Switch 8 Communication Control Device 9 Various sensors 41 Storage battery 42 BMU 81 Storage section 104 Battery Module Group

Claims

1. A plurality of battery modules; a connection path in which the plurality of battery modules are connected in parallel; an electrical load connected to the connection path; a switch capable of switching between an on state for connecting the battery module and the connection path and an off state for disconnecting the battery module and the connection path; a communication control device connected to the connection path and controlling switching of the switch; a power supply device connected to the connection path so as to be able to supply power to the plurality of battery modules and the communication control device; The battery module includes: A storage battery, A BMU that manages the state of the storage battery, The BMU of each of the plurality of battery modules has a common identification signal; the communication control device is provided with a storage unit that stores a voltage value of the storage battery for each of the battery modules; The communication control device includes: configured to control each BMU using the common identification signal; A charging / discharging device characterized in that, when all of the switches of the plurality of battery modules are in the off state, the switch of the battery module having the storage battery with the lowest voltage value among the voltage values ​​stored in the memory unit is switched to the on state.

2. a plurality of battery module groups each including the plurality of battery modules, the switch, and the communication control device; The charging / discharging device according to claim 1, characterized in that when the supply voltage from the power supply device is lower than the operating voltage of the BMU and the communication control device, when switching a battery module in one of a plurality of battery module groups whose switch is in the on state, the switch of any battery module in another battery module group is switched to the on state, and then the battery module in the one battery module group whose switch is in the on state is switched.

3. 3. The charging / discharging device according to claim 2, characterized in that after switching of a battery module in which the switch is in the on state in one battery module group is performed, the switch in the other battery module group that was switched to the on state is switched to the off state.

4. When the switch is a first switch, 4. The charging / discharging device according to claim 1, further comprising a second switch provided between the connection path and the power supply device and the electrical load, the second switch being capable of switching between an on state for connecting the connection path to the power supply device or the electrical load and an off state for disconnecting the connection path from the power supply device or the electrical load.

5. 5. The charging / discharging device according to claim 1, wherein the power supply device is configured by a power generation device that generates power by utilizing renewable energy.

6. 6. The charging / discharging device according to claim 1, wherein the electric load is a device having a light-emitting body as a load.

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