Energy storage system

Abstract

This system enables detection of the contact state between the cutoff switch and the bypass switch while keeping implementation costs down. [Solution] The energy storage system 1 includes a contact state detection circuit D1~Dn that connects the - terminal and + terminal of the interruption switch S1 and allows current to flow from the energy storage string STR or not depending on the potential difference between the - terminal and the + terminal, a microcontroller MCU connected to the contact state detection circuit D1~Dn with an input terminal IN and a ground terminal, the potential difference between the input terminal IN and the ground terminal changes depending on whether current flows through the contact state detection circuit D1~Dn or not, and a battery control device 100. The battery control device 100 determines the Open / Close state of the interruption switch S1 and the bypass switch S2 based on the potential difference between the input terminal IN and the ground terminal and the control information of the interruption switch S1, the bypass switch S2, and the system main relay S3.

Description

[Technical Field]

[0001] This invention relates to an energy storage system. [Background technology]

[0002] A known energy storage system is provided with an energy storage string in which multiple batteries are connected in series, and in which a bypass section is provided for each battery to switch between a connected state and a bypass state (see, for example, Patent Document 1). In the energy storage system described in Patent Document 1, a cutoff switch connected in series with the battery and a bypass switch connected in parallel with the battery and the cutoff switch are provided in the bypass section. In this energy storage system, if there is a battery that cannot discharge the required current, bypass control is performed in which the cutoff switch corresponding to that battery is opened and the bypass switch corresponding to that battery is closed, and discharge is performed from the other batteries. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-31247 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the energy storage system described in Patent Document 1, if the cutoff switch and the bypass switch are closed simultaneously due to a malfunction of the control system, a short circuit in the battery will occur. Possible methods to prevent the cutoff switch and the bypass switch from being closed simultaneously include detecting the potential difference between the terminals of the cutoff switch to confirm that the cutoff switch is open before closing the bypass switch, or detecting the potential difference between the terminals of the bypass switch to confirm that the bypass switch is open before closing the cutoff switch. However, this method requires that a contact state detection circuit to detect the state of the switch contacts be provided not only for the cutoff switch but also for the bypass switch, which increases the implementation cost.

[0005] In view of the above circumstances, the present invention aims to enable detection of the state of the contacts between a disconnect switch and a bypass switch in an energy storage system comprising an energy storage string in which a plurality of storage batteries are connected in series, and each storage battery is provided with a disconnect switch and a bypass switch, while keeping implementation costs down. [Means for solving the problem]

[0006] The present invention provides an energy storage system comprising an energy storage string in which a plurality of batteries are connected in series, the system comprising a first switch connected in series with the batteries, a second switch connected in parallel with the first switch and the batteries, a plurality of bypass sections that can be set to any of the following states: a connected state in which the first switch is closed and the second switch is open, a bypass state in which the first switch is open and the second switch is closed, and a disconnected state in which both the first and second switches are open, a third switch for connecting or disconnecting the energy storage string, and a first terminal located on the battery side of the first switch and a second terminal of the first switch. The device comprises a circuit through which current flows from the battery side or does not flow depending on the potential difference between the first terminal and the second terminal, an input terminal connected to the circuit, and a ground terminal, and a detection unit which detects when the potential difference between the input terminal and the ground terminal changes when current flows through the circuit and when current does not flow through the circuit, and a control unit which controls the first switch, the second switch and the third switch, and the control unit which determines whether the first switch and the second switch are open or closed based on the potential difference between the input terminal and the ground terminal of the detection unit and control information for controlling the first switch, the second switch and the third switch. [Effects of the Invention]

[0007] According to the present invention, in an energy storage system comprising an energy storage string in which multiple batteries are connected in series and each battery is provided with a cutoff switch and a bypass switch, the state of the contacts between the cutoff switch and the bypass switch can be detected while keeping implementation costs down. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic circuit diagram showing an energy storage system according to one embodiment of the present invention. [Figure 2] Figure 2 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 1. [Figure 3]Figure 3 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 1. [Figure 4] Figure 4 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 1. [Figure 5] Figure 5 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 1. [Figure 6] Figure 6 is a flowchart illustrating the contact state confirmation process during bypass control of the energy storage system shown in Figure 1. [Figure 7] Figure 7 is a flowchart illustrating the contact state confirmation process during connection control of the energy storage system shown in Figure 1. [Figure 8] Figure 8 is a schematic circuit diagram showing another embodiment of the present invention of an energy storage system. [Figure 9] Figure 9 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 8. [Figure 10] Figure 10 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 8. [Figure 11] Figure 11 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 8. [Figure 12] Figure 12 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 8. [Figure 13] Figure 13 is a schematic circuit diagram showing a power storage system according to another embodiment of the present invention. [Figure 14] Figure 14 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 13. [Figure 15] Figure 15 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 13. [Figure 16] Figure 16 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 13. [Figure 17] Figure 17 is a circuit diagram illustrating the contact state confirmation process of the energy storage system shown in Figure 13. [Figure 18] Figure 18 is a flowchart illustrating the contact state confirmation process during bypass control of the energy storage system shown in Figure 13. [Figure 19] Figure 19 is a flowchart illustrating the contact state confirmation process during connection control of the energy storage system shown in Figure 13. [Modes for carrying out the invention]

[0009] The present invention will be described below in accordance with preferred embodiments. However, the present invention is not limited to the embodiments shown below, and embodiments can be modified as appropriate without departing from the spirit of the invention. Furthermore, in the embodiments shown below, some components are not illustrated or described; however, details of the omitted technologies can be appropriately referred to from publicly known or well-known technologies, to the extent that they do not contradict the content described below.

[0010] Figure 1 is a schematic circuit diagram of an energy storage system 1 according to one embodiment of the present invention. As shown in this figure, the energy storage system 1 comprises an energy storage string STR, a power converter PCS, a string bus 2, and a battery control device 100. Although not shown, the energy storage system 1 comprises a plurality of energy storage strings STR, which are connected in parallel to each other via the string bus 2 and are also connected to an external system (not shown). The energy storage system 1 is a power source for stationary or vehicle-mounted use.

[0011] The energy storage string STR comprises n battery modules M1 to Mn (where n is an integer of 2 or more) connected in series. Although not particularly limited, the battery modules M1 to Mn in this embodiment are refurbished used batteries, and there are differences in the degree of degradation of each battery module M1 to Mn. The battery modules M1 to Mn are, for example, composed of multiple cells of secondary batteries such as lithium-ion batteries, lithium-ion capacitors, and nickel-metal hydride batteries connected together.

[0012] Battery modules M1 to Mn are charged by receiving power from the external grid via string bus 2 and power converter PCS. Conversely, battery modules M1 to Mn also supply power to the external grid via power converter PCS and string bus 2.

[0013] The external system includes loads and generators. If the energy storage system 1 is stationary, household appliances and the commercial power grid act as loads, while the solar power generation system and the commercial power grid act as generators. On the other hand, if the energy storage system 1 is vehicle-mounted, the drive motor, air conditioner, and various vehicle-mounted electrical components act as loads. Note that the drive motor acts as both a load and a generator.

[0014] The energy storage string STR may also consist of n battery cells or battery packs connected in series, instead of n battery modules M1 to Mn connected in series. Furthermore, the energy storage string STR may include bypass sections that bypass each battery cell or battery pack.

[0015] The power converter PCS is either a DC / DC converter or a DC / AC converter and is connected to string bus 2. The power converter PCS is also connected to the positive terminal of the starting battery module M1 (total + of the energy storage string STR) and the negative terminal of the ending battery module Mn (total - of the energy storage string STR).

[0016] The power converter PCS converts the voltage input from string bus 2 to the battery storage string STR according to the specified charging power (or current) value and outputs it to multiple battery storage modules M1 to Mn during charging. Here, the voltage on the battery storage string STR side changes depending on the bypass state of battery storage modules M1 to Mn (the number of battery storage modules M1 to Mn that are bypassed) and the charging state of battery storage modules M1 to Mn. Therefore, the power converter PCS converts the voltage input from string bus 2 to the voltage on the battery storage string STR side and outputs it to multiple battery storage modules M1 to Mn during charging.

[0017] The power converter PCS, during the discharge of the energy storage string STR, converts the voltages input from multiple battery modules M1 to Mn according to the indicated discharge power (or current) value and outputs it to the string bus 2. Here, the input voltage of the power converter PCS during discharge changes depending on the bypass state and charge state of the battery modules M1 to Mn. As a result, variations occur in the input voltage of the power converter PCS among the energy storage strings STR during discharge. Therefore, during the discharge of the energy storage string STR, the power converter PCS converts the input voltage to a voltage that matches that of the other energy storage strings STR and outputs it to the string bus 2.

[0018] The power converter PCS is a bidirectional converter. Furthermore, when the current flowing through string bus 2 is alternating current, the power converter PCS is equipped with synchronization means to track changes in instantaneous values.

[0019] The energy storage string STR comprises n bypass units B1 to Bn, a system main relay S3, n contact state detection circuits D1 to Dn, and various sensors (not shown). The bypass units B1 to Bn and the contact state detection circuits D1 to Dn are provided for each battery module M1 to Mn.

[0020] Each bypass unit B1 to Bn is equipped with a disconnection switch S1, a bypass line BL, and a bypass switch S2. The disconnection switch S1 is a mechanical relay connected in series with each battery module M1 to Mn. The disconnection switch S1 is located on the total positive side of the energy string STR relative to each battery module M1 to Mn. Note that the disconnection switch S1 may also be a semiconductor switch or the like.

[0021] Bypass line BL is a power line that bypasses each battery module M1 to Mn and the circuit breaker switch S1. A mechanical relay, the bypass switch S2, is provided on this bypass line BL. Specifically, the bypass switch S2 is connected in parallel with each battery module M1 to Mn and the circuit breaker switch S1. Note that the bypass switch S2 may also be a semiconductor switch or the like.

[0022] The starting battery module M1 and the ending battery module Mn are connected to the external system via the power converter PCS and string bus 2. When the bypass switch S2 is open and the circuit breaker switch S1 is closed in all bypass units B1 to Bn, all battery modules M1 to Mn are connected in series to the external system. On the other hand, when the circuit breaker switch S1 is open and the bypass switch S2 is closed in any of the bypass units B1 to Bn, the battery modules M1 to Mn corresponding to that bypass unit B1 to Bn are bypassed. Note that when it is not necessary to distinguish each bypass unit B1 to Bn from other bypass units B1 to Bn, they will be referred to as bypass unit B. Similarly, when it is not necessary to distinguish each battery module M1 to Mn from other battery modules M1 to Mn, they will be referred to as battery module M.

[0023] The system main relay S3 is located at a position on the power line PL that is always energized. Specifically, the system main relay S3 is located between the total positive terminal of the energy storage string STR and the trip switch S1 of the bypass unit B1 at the start. The system main relay S3 is a mechanical relay, a semiconductor switch, etc. Alternatively, the system main relay S3 may be located between the total negative terminal of the energy storage string STR and the battery module Mn at the end. Alternatively, the system main relay S3 may be located between the total positive terminal of the energy storage string STR and the trip switch S1 of the bypass unit B1 at the start, and a second system main relay (not shown) may be located between the total negative terminal of the energy storage string STR and the battery module Mn at the end.

[0024] Each contact state detection circuit D1 to Dn comprises two resistors R1 and R2 and a Zener diode ZD. When it is not necessary to distinguish each contact state detection circuit D1 to Dn from the other contact state detection circuits D1 to Dn, they will be referred to simply as contact state detection circuit D.

[0025] The connection state detection circuit D connects the terminals on both sides of the cutoff switch S1. Among the terminals on both sides of the cutoff switch S1, the terminal located on the total + side of the power storage string STR is defined as the + side terminal T + (see Fig. 2 etc.). Among the terminals on both sides of the cutoff switch S1, the terminal located on the total - side of the power storage string STR is defined as the - side terminal T - (see Fig. 2 etc.). The - side terminal T of the cutoff switch S1 - corresponds to the terminal located on the side of the battery module M.

[0026] The cathode of the Zener diode ZD is connected to one end of the resistor R2, the input terminal IN of the microcontroller MCU, and one end of the resistor R1. One end of the resistor R2 is connected to the cathode of the Zener diode ZD, the input terminal IN of the microcontroller MCU, and one end of the resistor R1, and the other end of the resistor R2 is connected to the - side terminal T of the cutoff switch S1 - and the + terminal of the battery module M. That is, the cathode of the Zener diode ZD is connected to the - side terminal T of the cutoff switch S1 - and the + terminal of the battery module M through the resistor R2. Also, the - side terminal T of the cutoff switch S1 - and the + terminal of the battery module M are connected to the cathode of the Zener diode ZD, the input terminal IN of the microcontroller MCU, and the resistor R1 through the resistor R2.

[0027] The anode of the Zener diode ZD is connected to the + side terminal T of the cutoff switch S1 + and the other end of the resistor R1 and the ground GND. The other end of the resistor R1 is connected to the + side terminal T of the cutoff switch S1 + and the anode of the Zener diode ZD and the ground GND. That is, the + side terminal T of the cutoff switch S1 + and the anode of the Zener diode ZD and the other end of the resistor R1 are connected to the ground GND.

[0028] Here, resistor R1 is a pull-down resistor that maintains the voltage of the contact state detection circuit D at a low voltage when no current is flowing. In contrast, resistor R2 is a current-limiting resistor that limits the current flowing from the battery module M to the Zener diode ZD.

[0029] The battery control device 100 comprises a system controller SysC, a string controller StC, and module controllers MC1 to MCn. A system controller SysC is provided for each energy storage system 1. Although not shown in the diagram, the battery control device 100 comprises multiple string controllers StC, and each string controller StC is provided for each energy storage string STR. Module controllers MC1 to MCn are provided for each battery module M.

[0030] Module controllers MC1 to MCn each consist of a microcontroller (MCU) and a relay driver (RD). When it is not necessary to distinguish each module controller MC1 to MCn from others, they will simply be referred to as module controller MC.

[0031] The microcontroller (MCU) is a control device that performs control and status monitoring of the battery module M and the bypass unit B, and transmits status information of the corresponding battery module M to the string controller (StC). This status information of the battery module M includes the voltage, temperature, and cell voltage of the battery module M.

[0032] Furthermore, the microcontroller MCU determines whether it is necessary to switch the cutoff switch S1 and bypass switch S2 of the corresponding bypass unit B based on the voltage and SOC (State of Charge) of the corresponding battery module M. For example, when the energy storage string STR is discharging, if the voltage or SOC of the corresponding battery module M falls below a threshold, the microcontroller MCU determines that it is necessary to switch the cutoff switch S1 from Close to Open and the bypass switch S2 from Open to Close (hereinafter referred to as bypass control) for the corresponding bypass unit B. Also, for example, when the energy storage string STR is charging, if the voltage or SOC of the corresponding battery module M rises above a threshold, the microcontroller MCU determines that it is necessary to switch the corresponding bypass unit B. Note that the determination of whether it is necessary to switch the cutoff switch S1 and bypass switch S2 of the bypass unit B may be performed by the string controller StC. In addition, when the voltage or SOC of the battery module M is below or above a threshold, bypass control and control to release the bypass state (hereinafter referred to as connection control) may be performed.

[0033] When the microcontroller MCU determines that switching of the cutoff switch S1 and bypass switch S2 is necessary for the corresponding bypass unit B, it sends a signal to the string controller StC requesting the switching of the cutoff switch S1 and bypass switch S2 (hereinafter referred to as the switch switching request signal). The microcontroller MCU also sends the logical value (High / Low) of the input terminal IN to the string controller StC. The logical value of the input terminal IN is Low when the potential difference between the input terminal IN and the ground terminal is relatively small (less than a predetermined value ΔV), and High when the potential difference between the input terminal IN and the ground terminal is relatively large (greater than or equal to a predetermined value ΔV). Specifically, the logical value of the input terminal IN is Low when no current flows through the Zener diode ZD, and High when current flows through the Zener diode ZD.

[0034] The string controller StC transmits the switch switching request signal received from the module controller MC to the system controller SysC. However, if the string controller StC can determine whether to allow or disallow the switching of the disconnect switch S1 and bypass switch S2, it is not necessary for the string controller StC to transmit the switch switching request signal to the system controller SysC.

[0035] When the system controller SysC receives a switch switching request signal from the string controller StC, it determines whether to allow or deny the switching of the cutoff switch S1 and the bypass switch S2. If the system controller SysC allows the switching of the cutoff switch S1 and the bypass switch S2, it sends a signal instructing the switch to switch (hereinafter referred to as the switch switching signal) to the string controller StC. The string controller StC then sends the switch switching signal received from the system controller SysC to the target module controller MC.

[0036] Here, the string controller StC performs a process to check the contact status of the disconnect switch S1 and bypass switch S2 (hereinafter referred to as the contact status check process) when bypass control and connection control are performed. Alternatively, the microcontroller MCU may perform the contact status check process. The contact status check process will be described later.

[0037] The microcontroller (MCU) sends a switch switching signal to the relay driver (RD) when performing bypass control, connection control, and contact state check processing. The relay driver (RD) switches or maintains the Open / Close state of the corresponding disconnect switch (S1) and bypass switch (S2) according to the switch switching signal received from the microcontroller (MCU).

[0038] The string controller StC transmits control signals to the power converter PCS. The power converter PCS converts the charging and discharging power of the energy storage string STR according to the control signals transmitted from the string controller StC. The power converter PCS also controls the string current of the energy storage string STR according to the control signals from the string controller StC.

[0039] The string controller StC performs detection and estimation of the state of the energy storage string STR. Detection of the state of the energy storage string STR includes detecting the string current of the energy storage string STR based on the detection signal of a current sensor (not shown), detecting the total voltage of the energy storage string STR based on the detection signal of a voltage sensor (not shown), detecting the voltage of the battery module M based on the detection signal of a voltage sensor, detecting the temperature of the battery module M based on the detection signal of a temperature sensor (not shown), and detecting the voltage of the battery cells based on the detection signal of a cell voltage sensor (not shown). Furthermore, estimation of the state of the energy storage string STR includes estimating the SOC and SOH (State of Health) of the battery module M, and estimating the SOC and SOH of the energy storage string STR.

[0040] The system controller SysC is the controller that comprehensively controls the entire energy storage system 1 and performs 1:m communication with multiple string controllers StC. This system controller SysC monitors the status of the energy storage strings STR, determines whether to grant or deny control requests for equipment such as bypass units B from the string controllers StC, and notifies the string controllers StC of the permission / denial of equipment control requests. In addition, the system controller SysC sets the indicative value of the charge / discharge power (or current) for each energy storage string STR and transmits the indicative value of said charge / discharge power (or current) to the string controllers StC.

[0041] The system controller SysC monitors the state of the energy storage strings STR based on the detection and estimation results of the state of the energy storage strings STR transmitted from the string controller StC. Then, the system controller SysC calculates the instructed charge / discharge power (or current) value to be allocated to each energy storage string STR, based on the input / output power (or current) instruction for the entire energy storage system 1 received from a higher-level system (not shown) and the state of the energy storage strings STR.

[0042] Figures 2 to 5 are circuit diagrams illustrating the contact state confirmation process of the energy storage system 1 shown in Figure 1. Note that in bypass unit B, the state where the disconnect switch S1 is closed and the bypass switch S2 is open is described as the connected state. Furthermore, in bypass unit B, the state where the disconnect switch S1 is open and the bypass switch S2 is closed is described as the bypass state. Finally, in bypass unit B, the state where both the disconnect switch S1 and the bypass switch S2 are open is described as the disconnected state.

[0043] Figure 2 is a circuit diagram showing the state of the contact state detection circuit D corresponding to the bypass unit B in the bypass state. As shown in this figure, the contact state detection circuit D corresponding to the bypass unit B in the bypass state connects to the + side terminal T of the cutoff switch S1 via the bypass switch S2 and the battery module M. + and the negative terminal T - This results in a connected state. Therefore, regardless of the state of the system main relay S3 and other bypass units B, current flows through the Zener diode ZD corresponding to the bypass unit B in the bypass state. At this time, the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B in the bypass state becomes High.

[0044] Figure 3 is a circuit diagram showing the state of the contact state detection circuit D corresponding to the connected bypass unit B. In the state shown in this figure, the system main relay S3 may be either closed or open, and the other bypass unit B may be in a connected state, a bypass state, or an interrupted state.

[0045] As shown in Figure 3, regardless of the state of the system main relay S3 and other bypass units B, in the connected bypass unit B, the + terminal T of the disconnect switch S1 is + and the negative terminal T - No potential difference is generated between them. Therefore, no current flows through the Zener diode ZD corresponding to the bypass unit B. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the bypass unit B becomes Low.

[0046] Figure 4 is a circuit diagram showing the state of the contact state detection circuit D corresponding to the bypass unit B in the disconnected state. In the state shown in this figure, the system main relay S3 is closed, and the other bypass units B may be in the connected, bypassed, or disconnected state.

[0047] As shown in Figure 4, when the system main relay S3 is closed, regardless of the state of other bypass units B, the + terminal T of the disconnect switch S1 is closed in the disconnected bypass unit B. + and the negative terminal T - A potential difference is created between the two points. As a result, current flows through the Zener diode ZD corresponding to the bypass unit B. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the bypass unit B becomes High.

[0048] Figure 5 is a circuit diagram showing the state of the contact state detection circuit D corresponding to the bypass unit B in the disconnected state when the system main relay S3 is open. In the state shown in this figure, the state of the other bypass unit B may be connected, bypassed, or disconnected.

[0049] As shown in Figure 5, when the system main relay S3 is open, the contact state detection circuit D corresponding to the interrupted bypass unit B becomes open, regardless of the state of other bypass units B. Therefore, no current flows through the Zener diode ZD in the contact state detection circuit D. In this case, the logic value of the input terminal IN of the microcontroller MCU corresponding to the interrupted bypass unit B becomes low.

[0050] Figure 6 is a flowchart illustrating the contact state confirmation process during bypass control execution of the energy storage system 1 shown in Figure 1. The process shown in this flowchart begins when the string controller StC receives a bypass control switch switching signal from the system controller SysC. Each time the string controller StC transmits a switch switching signal to the module controller MC, it stores in memory the Open / Close information (hereinafter referred to as control information) of the disconnect switch S1 and bypass switch S2 corresponding to the switch switching signal. In addition, each time the string controller StC switches the Open / Close state of the system main relay S3, it stores in memory the Open / Close information (hereinafter referred to as control information) of the system main relay S3.

[0051] First, the string controller StC opens the system main relay (SMR) S3 (step S1). If the system main relay S3 is open at the start of processing, it remains open.

[0052] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B with the bypass switch S2 open is Low (step S2). In step S2, the string controller StC determines whether the bypass switch S2 is open or closed by referring to the control information stored in memory.

[0053] Here, as shown in Figures 3 and 5, when the system main relay S3 is open, no current flows to the contact state detection circuit D corresponding to the bypass unit B where the bypass switch S2 is open. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes Low. Therefore, if the bypass switch S2 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S2.

[0054] If a negative determination is made in step S2, the string controller StC sends a signal to the system controller SysC indicating an abnormal contact state of the malfunctioning bypass switch S2 (hereinafter referred to as the abnormality notification signal) (step S13). Conversely, if a positive determination is made in step S2, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B that is closed by the bypass switch S2 is High (step S3). In step S3, the string controller StC determines whether the bypass switch S2 is Open / Close by referring to the control information stored in memory.

[0055] Here, as shown in Figure 2, in the contact state detection circuit D corresponding to the bypass unit B in the bypass state, current flows through the Zener diode ZD regardless of the state of the system main relay S3 and the other bypass units B. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes High. Therefore, if the bypass switch S2 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S3.

[0056] If a negative determination is made in step S3, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning bypass switch S2 (step S13). Conversely, if a positive determination is made in step S3, the string controller StC closes the system main relay S3 (step S4).

[0057] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B with the cutoff switch S1 open is High (step S5). In step S5, the string controller StC determines whether the cutoff switch S1 is Open or Close by referring to the control information stored in memory.

[0058] Here, when the system main relay S3 is closed, regardless of the state of other bypass units B, current flows through the Zener diode ZD in the contact state detection circuit D corresponding to the bypass unit B where the cutoff switch S1 is open (see Figures 2 and 4). In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes High. Therefore, if the cutoff switch S1 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S5.

[0059] If a negative determination is made in step S5, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning cutoff switch S1 (step S13). Conversely, if an affirmative determination is made in step S5, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B that is closed for the cutoff switch S1 is Low (step S6). In step S6, the string controller StC determines whether the cutoff switch S1 is Open or Closed by referring to the control information stored in memory.

[0060] Here, as shown in Figure 3, regardless of the state of the system main relay S3 and other bypass units B, no current flows in the contact state detection circuit D corresponding to the bypass unit B where the bypass switch S2 is open and the cutoff switch S1 is closed. In this case, the logic value of the input terminal IN in the corresponding microcontroller MCU becomes Low. Therefore, if the cutoff switch S1 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S6.

[0061] If a negative determination is made in step S6, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning cutoff switch S1 (step S13). Conversely, if a positive determination is made in step S6, the string controller StC sends a switch switching signal to the module controller MC corresponding to the cutoff switch S1 that is the target of bypass control, to open the cutoff switch S1 that is the target of bypass control (step S7).

[0062] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be bypassed is High (step S8).

[0063] Here, as shown in Figure 4, when the system main relay S3 is closed, regardless of the state of other bypass units B, current flows through the Zener diode ZD in the contact state detection circuit D corresponding to the bypass unit B where both the bypass switch S2 and the cutoff switch S1 are open. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes high. Therefore, if the cutoff switch S1 is successfully switched to open in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S8.

[0064] If a negative determination is made in step S8, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning cutoff switch S1 (step S13). Conversely, if a positive determination is made in step S8, the string controller StC opens the system main relay S3 (step S9).

[0065] Next, the string controller StC sends a switch switching signal to the module controller MC corresponding to the bypass switch S2 that is to be bypassed, to close the bypass switch S2 that is to be bypassed (step S10).

[0066] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be bypassed is High (step S11).

[0067] Here, as shown in Figure 2, in the contact state detection circuit D corresponding to bypass unit B where bypass switch S2 is Close and cutoff switch S1 is Open, current flows through the Zener diode ZD. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes High. Therefore, if the bypass switch S2 is successfully switched to Close in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S11.

[0068] If a negative result is obtained in step S11, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning bypass switch S2 (step S13). Conversely, if a positive result is obtained in step S11, the string controller StC closes the system main relay S3 (step S12). This completes the process.

[0069] Figure 7 is a flowchart illustrating the contact state confirmation process during connection control of the energy storage system 1 shown in Figure 1. The process shown in this flowchart starts when the string controller StC receives a connection control switch switching signal from the system controller SysC. Note that steps S1 to S6 and S13 are the same as steps S1 to S6 and S13 of the contact state confirmation process during bypass control execution, so their explanation is omitted.

[0070] If a positive determination is made in step S6, the string controller StC opens the system main relay S3 (step S107). Next, the string controller StC sends a switch switching signal to the module controller MC corresponding to the bypass switch S2 that corresponds to the battery module M to be controlled, to open the bypass switch S2 (step S108).

[0071] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be controlled is Low (step S109).

[0072] Here, as shown in Figure 5, when the system main relay S3 is open, no current flows through the contact state detection circuit D corresponding to the bypass unit B where both the bypass switch S2 and the cutoff switch S1 are open. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes Low. Therefore, if the bypass switch S2 is successfully switched to Open in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S110.

[0073] If a negative determination is made in step S109, the string controller StC sends an abnormal notification signal for the malfunctioning bypass switch S2 to the system controller SysC (step S13). Conversely, if a positive determination is made in step S109, the string controller StC closes the system main relay S3 (step S110). Next, the string controller StC sends a switch switching signal to the module controller MC corresponding to the bypass unit B to close the disconnection switch S1 corresponding to the battery module M that is the target of connection control (step S111).

[0074] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be controlled is Low (step S112).

[0075] Here, as shown in Figure 3, regardless of the state of the system main relay S3 and other bypass units B, no current flows through the contact state detection circuit D corresponding to the bypass unit B where the bypass switch S2 is Open and the cutoff switch S1 is Closed. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D becomes Low. Therefore, if the cutoff switch S1 is successfully switched to Close in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S112.

[0076] If a negative determination is made in step S112, the string controller StC sends an abnormal notification signal regarding the malfunctioning cutoff switch S1 to the system controller SysC (step S13). Conversely, if a positive determination is made in step S112, the process terminates.

[0077] As described above, the energy storage system 1 according to this embodiment has the + side terminal T of the cutoff switch S1. + and the negative terminal T -The system includes a contact state detection circuit D that connects to the + terminal T of the cutoff switch S1, a microcontroller MCU connected to the contact state detection circuit D, and a battery control device 100. + and the negative terminal T - Depending on the potential difference, current may or may not flow from the battery module M side.

[0078] The microcontroller (MCU) has an input terminal IN and a ground terminal connected to a contact state detection circuit D. In this microcontroller (MCU), the potential difference between the input terminal IN and the ground terminal changes depending on whether current is flowing through the contact state detection circuit D or not.

[0079] The string controller StC of the battery control device 100 determines whether the disconnect switch S1 and the bypass switch S2 are open or closed based on the potential difference between the input terminal IN of the microcontroller MCU and the ground terminal, and the control information of the disconnect switch S1, the bypass switch S2, and the system main relay S3.

[0080] For example, the string controller StC determines that the target bypass switch S2 is open if the system main relay S3 is open and the logic value of the input terminal IN of the target microcontroller MCU is low. Also, the string controller StC determines that the target bypass switch S2 is closed if the system main relay S3 is open and the logic value of the input terminal IN of the target microcontroller MCU is high.

[0081] For example, the string controller StC determines that the target disconnect switch S1 is open if the logical value of the input terminal IN of the target microcontroller MCU is High while the system main relay S3 is Close. Also, the string controller StC determines that the target disconnect switch S1 is Close if the logical value of the input terminal IN of the target microcontroller MCU is Low while the system main relay S3 is Close.

[0082] Therefore, according to the energy storage system 1 of this embodiment, the contact state of the cutoff switch S1 and the bypass switch S2 can be checked, thus preventing the cutoff switch S1 and the bypass switch S2 from closing simultaneously due to a malfunction of the control system. Furthermore, since the contact state detection circuit D only needs to be connected to the cutoff switch S1 and a contact state detection circuit connected to the bypass switch S2 is not necessary, the detection of the contact state of the cutoff switch S1 and the bypass switch S2 can be achieved while keeping implementation costs down.

[0083] Furthermore, in the energy storage system 1 according to this embodiment, the contact state detection circuit D includes a current limiting resistor R2, a Zener diode ZD, and a pull-down resistor R1. The resistor R2 is connected to the negative terminal T of the cutoff switch S1. - The cathode of the Zener diode ZD is connected to resistor R2 and the input terminal IN of the microcontroller MCU, and the anode of the Zener diode ZD is connected to the + terminal T of the cutoff switch S1. + It is connected to ground GND. Resistor R1 is connected to the input terminal IN and ground GND.

[0084] This results in the positive terminal T of the cutoff switch S1. + and the negative terminal T - If no potential difference occurs between the two, no current flows through the Zener diode ZD of the contact state detection circuit D. In contrast, the positive terminal T of the cutoff switch S1 + and the negative terminal T -When a potential difference occurs between the input terminal IN and the ground terminal of the microcontroller MCU, current flows through the Zener diode ZD of the contact state detection circuit D. When no current flows through the Zener diode ZD, no potential difference occurs between the input terminal IN and the ground terminal of the microcontroller MCU. When current flows through the Zener diode ZD, a potential difference occurs between the input terminal IN and the ground terminal of the microcontroller MCU. Therefore, the string controller StC can determine whether the interruption switch S1 and the bypass switch S2 are open or closed, based on the potential difference between the input terminal IN and the ground terminal of the microcontroller MCU and the control information of the interruption switch S1, the bypass switch S2, and the system main relay S3.

[0085] Furthermore, in the energy storage system 1 according to this embodiment, the string controller StC performs the following processing when the system main relay S3 is controlled to Close. In a microcontroller MCU corresponding to bypass unit B, where the state of bypass switch S2 according to the control information is Open or Close and the state of cutoff switch S1 according to the control information is Open, if the potential difference between the input terminal IN and the ground terminal is greater than or equal to a predetermined value ΔV, the cutoff switch S1 corresponding to the microcontroller MCU is determined to be Open. In a microcontroller MCU corresponding to bypass unit B, where the state of bypass switch S2 according to the control information is Open and the state of cutoff switch S1 according to the control information is Close, the cutoff switch S1 corresponding to the microcontroller MCU is determined to be Close when the potential difference between the input terminal IN and the ground terminal is less than a predetermined value ΔV.

[0086] This allows the contact state of the disconnect switch S1 to be checked when the system main relay S3 is closed and all bypass units B are controlled to be either connected or bypassed. Furthermore, it is possible to confirm that the disconnect switch S1 has been successfully switched to Open during bypass control, which switches a bypass unit B from the connected state to the bypass state. In this embodiment of the energy storage system 1, even if there is a battery module M in the disconnected state, current flows from that battery module M to other battery modules M through the contact state detection circuit D. Therefore, it is not necessary to control all bypass units B to be either connected or bypassed when executing the above process. However, if the configuration is such that current does not flow from a battery module M in the disconnected state to other battery modules M, the above process is executed when the system main relay S3 is closed and all bypass units B are controlled to be either connected or bypassed.

[0087] Furthermore, in the energy storage system 1 according to this embodiment, the string controller StC performs the following processing when the system main relay S3 is controlled to be open. In a microcontroller MCU corresponding to bypass unit B, where the state of bypass switch S2 according to control information is Open and the state of cutoff switch S1 according to control information is Open or Close, the bypass switch S2 corresponding to the microcontroller MCU is determined to be Open when the potential difference between the input terminal IN and the ground terminal is less than a predetermined value ΔV. In a microcontroller MCU corresponding to bypass unit B, where the state of bypass switch S2 according to the control information is Close and the state of cutoff switch S1 according to the control information is Open, the bypass switch S2 corresponding to the microcontroller MCU is determined to be Close when the potential difference between the input terminal IN and the ground terminal is greater than or equal to a predetermined value ΔV.

[0088] This allows you to check the contact state of the bypass switch S2 when the system main relay S3 is controlled to Open. Furthermore, it allows you to confirm that the bypass switch S2 has been successfully switched to Close during bypass control, which switches the connected bypass unit B to the bypass state.

[0089] Figure 8 is a schematic circuit diagram showing an energy storage system 11 according to another embodiment of the present invention. The energy storage system 11 shown in Figure 8 includes contact state detection circuits D1' to Dn' which have a different configuration from the contact state detection circuits D1 to Dn described above. Components similar to those in the above embodiments are denoted by the same reference numerals, and the descriptions of the above embodiments will be used accordingly.

[0090] As shown in Figure 8, each contact state detection circuit D1'~Dn' consists of three resistors R1, R2, R3 and a PNP type transistor T PNP It is equipped with the following. Furthermore, if it is not necessary to distinguish each contact state detection circuit D1'~Dn' from other contact state detection circuits D1'~Dn', it will be referred to simply as contact state detection circuit D'.

[0091] The contact state detection circuit D' is connected to the positive terminal T of the cutoff switch S1. + (See Figure 9, etc.) and the negative terminal T - Connect it to (see Figure 9, etc.). Transistor T PNP The base of the resistor is connected to one end of resistor R2. The other end of resistor R2 is connected to the negative terminal T of the cutoff switch S1. - It is connected to the + terminal of the battery module M. That is, transistor T PNP The base is connected to the negative terminal T of the cutoff switch S1 via resistor R2. - It is connected to the + terminal of the battery module M. One end of resistor R3 is connected to transistor T PNP It is connected to the base of the transistor T, and the other end of resistor R3 is connected to the transistor T. PNP It is connected to the emitter.

[0092] Transistor T PNP The emitter of is connected to the power supply Vcc. Also, transistor TPNP The collector of the resistor is connected to one end of resistor R1 and to the input terminal IN of the microcontroller MCU. The other end of resistor R1 is connected to the + terminal T of the cutoff switch S1. + It is connected to ground GND. That is, transistor T PNP The collector of the switch is connected to the positive terminal T of the cutoff switch S1 via resistor R1. + It is connected to ground (GND).

[0093] Here, resistor R1 is a pull-down resistor that maintains the voltage of the contact state detection circuit D' at a low voltage when there is no input. In contrast, resistor R2 is connected to transistor T from the battery module M side. PNP This is a current-limiting resistor that restricts the current flowing through it. Additionally, resistor R3 is a base-emitter resistor that prevents the base potential from becoming undefined when the circuit is open.

[0094] Figures 9 to 12 are circuit diagrams illustrating the contact state confirmation process of the energy storage system 11 shown in Figure 8. Figure 9 is a circuit diagram showing the state of the contact state detection circuit D' corresponding to the bypass unit B in the bypass state. As shown in this figure, the contact state detection circuit D' corresponding to the bypass unit B in the bypass state connects to the + side terminal T of the cutoff switch S1 via the bypass switch S2 and the battery module M. + and the negative terminal T - It becomes connected to the system main relay S3 and the other bypass unit B. Therefore, regardless of the state of the bypass unit B in the bypass state, the transistor T corresponding to the bypass unit B is connected to the system main relay S3. PNP When the switch is turned ON, current flows between the emitter and collector. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to bypass unit B, which is in the bypass state, becomes High.

[0095] Figure 10 is a circuit diagram showing the state of the contact state detection circuit D' corresponding to the connected bypass unit B. In the state shown in this figure, the system main relay S3 is closed, and the other bypass units B may be in the connected, bypassed, or disconnected state.

[0096] As shown in Figure 10, when the system main relay S3 is closed, regardless of the state of other bypass units B, the connected bypass unit B has the + terminal T of the disconnect switch S1. + and the negative terminal T - No potential difference is generated between it and the transistor T corresponding to the bypass unit B. PNP The switch turns OFF, and no current flows between the emitter and collector. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to bypass unit B becomes Low.

[0097] Figure 11 is a circuit diagram showing the state of the contact state detection circuit D' corresponding to the bypass unit B in the disconnected state. In the state shown in this figure, the system main relay S3 is closed, and the other bypass units B may be in the connected, bypassed, or disconnected state.

[0098] As shown in Figure 11, when the system main relay S3 is closed, regardless of the state of other bypass units B, the + terminal T of the disconnect switch S1 is closed in the disconnected bypass unit B. + and the negative terminal T - A potential difference is generated between it and the transistor T corresponding to the bypass unit B. PNP When this is turned ON, current flows between the emitter and collector. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the bypass unit B becomes High.

[0099] Figure 12 is a circuit diagram showing the state of the contact state detection circuit D' corresponding to the bypass unit B in the disconnected state when the system main relay S3 is open. In the state shown in this figure, the state of the other bypass unit B may be connected, bypassed, or disconnected.

[0100] As shown in Figure 12, when the system main relay S3 is open, the contact state detection circuit D' corresponding to the bypass unit B in the closed state becomes open, regardless of the state of the other bypass units B. Therefore, in the contact state detection circuit D', transistor T PNP The switch turns OFF, and no current flows between the emitter and collector. In this state, the logic value of the input terminal IN in the microcontroller MCU corresponding to the bypass unit B in the OFF state becomes Low.

[0101] The contact state confirmation process during bypass control in the energy storage system 11 according to this embodiment is the same as in the embodiment described above, so the description of the embodiment described above will be used with reference. In addition, in the contact state confirmation process during connection control in the energy storage system 11 according to this embodiment, steps S1 to S4 are executed as in the embodiment described above, then control is performed to set all bypass units B to a connected state or a bypass state, and then steps S5 to S13 are performed as in the embodiment described above.

[0102] As described above, in the energy storage system 11 according to this embodiment, the contact state detection circuit D' consists of a resistor R2 which is a current limiting resistor and a PNP type transistor T which is a switching element. PNP It also includes a pull-down resistor R1. Resistor R2 is connected to the negative terminal T of the cutoff switch S1. - It is connected to transistor T. PNP The base of is connected to resistor R2, and transistor T PNP The emitter of is connected to the power supply Vcc, and transistor T PNP The collector of the resistor is connected to the input terminal IN. Resistor R1 is connected to transistor T PNP The collector and the positive terminal T of the cutoff switch S1 + It is connected to the input terminal IN and ground GND.

[0103] This results in the positive terminal T of the cutoff switch S1. + and the negative terminal T - If no potential difference occurs between the two points, no current flows through the contact state detection circuit D', and the positive terminal T of the cutoff switch S1 does not flow.+ and the negative terminal T - When a potential difference occurs between the two, current flows from the contact state detection circuit D' to the bypass unit B. Transistor T PNP When it is OFF, no potential difference occurs between the input terminal IN and the ground terminal of the microcontroller MCU, and transistor T PNP When the switch is turned ON by current or voltage, a potential difference is generated between the input terminal IN of the microcontroller MCU and the ground terminal. Therefore, the string controller StC can determine whether the interruption switch S1 and the bypass switch S2 are open or closed based on the potential difference between the input terminal IN of the microcontroller MCU and the ground terminal, and the control information of the interruption switch S1, the bypass switch S2, and the system main relay S3.

[0104] Figure 13 is a schematic circuit diagram showing a power storage system 21 according to another embodiment of the present invention. The power storage system 21 shown in Figure 13 includes contact state detection circuits D1'' to Dn'' which have a different configuration from the contact state detection circuits D1'' to Dn'' and D1'' to Dn'' described above. Components similar to those in the above embodiments are denoted by the same reference numerals, and the descriptions of the above embodiments will be used accordingly.

[0105] As shown in Figure 13, each contact state detection circuit D1"~Dn" consists of three resistors R1, R2, and R3, and an NPN transistor T NPN It is equipped with the following. Furthermore, if there is no need to distinguish each contact state detection circuit D1"~Dn" from other contact state detection circuits D1"~Dn", it will be referred to as contact state detection circuit D"".

[0106] The contact state detection circuit D'' is connected to the positive terminal T of the cutoff switch S1. + (See Figure 14, etc.) and the negative terminal T - Connect to (see Figure 14, etc.). Transistor T NPN The base of the resistor is connected to one end of resistor R2. The other end of resistor R2 is connected to the negative terminal T of the cutoff switch S1. - It is connected to the + terminal of the battery module M. That is, transistor TNPN The base is connected to the negative terminal T of the cutoff switch S1 via resistor R2. - It is connected to the + terminal of the battery module M. One end of resistor R3 is connected to transistor T NPN It is connected to the base of the transistor T, and the other end of resistor R3 is connected to the transistor T. NPN It is connected to the emitter.

[0107] Transistor T NPN The collector of the transistor T is connected to one end of resistor R1 and to the input terminal IN of the microcontroller MCU. The other end of resistor R1 is connected to the power supply Vcc. That is, transistor T NPN The collector of is connected to the power supply Vcc via resistor R1. Also, transistor T NPN The emitter is connected to the positive terminal T of the cutoff switch S1. + It is connected to ground (GND).

[0108] Here, resistor R1 is a pull-up resistor that maintains the voltage of the contact state detection circuit D'' at Vcc voltage when there is no input. On the other hand, resistor R2 is connected to transistor T from the battery module M side. NPN This is a current-limiting resistor that restricts the current flowing through it. Additionally, resistor R3 is a base-emitter resistor that prevents the base potential from becoming undefined when the circuit is open.

[0109] Figures 14 to 17 are circuit diagrams illustrating the contact state confirmation process of the energy storage system 21 shown in Figure 13. Figure 14 is a circuit diagram showing the state of the contact state detection circuit D'' corresponding to the bypass unit B in the bypass state. As shown in this figure, the contact state detection circuit D'' corresponding to the bypass unit B in the bypass state connects to the + side terminal T of the cutoff switch S1 via the bypass switch S2 and the battery module M. + and the negative terminal T - It becomes connected to the system main relay S3 and the other bypass unit B. Therefore, regardless of the state of the bypass unit B in the bypass state, the transistor T corresponding to the bypass unit B is connected to the system main relay S3. NPNWhen the switch is turned ON, current flows between the collector and emitter. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to bypass unit B, which is in the bypass state, becomes Low.

[0110] Figure 15 is a circuit diagram showing the state of the contact state detection circuit D'' corresponding to the connected bypass unit B. In the state shown in this figure, the system main relay S3 may be either Closed or Open, and the other bypass unit B may be in a connected state, a bypass state, or an interrupted state.

[0111] As shown in Figure 15, regardless of the state of the system main relay S3 and other bypass units B, in the connected bypass unit B, the + terminal T of the disconnect switch S1 is + and the negative terminal T - No potential difference is generated between it and the transistor T corresponding to the bypass unit B. NPN The switch turns OFF, and no current flows between the collector and emitter. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to bypass unit B becomes High.

[0112] Figure 16 is a circuit diagram showing the state of the contact state detection circuit D'' corresponding to the bypass unit B in the disconnected state. In the state shown in this figure, the system main relay S3 is Close, and the other bypass units B may be in the connected, bypassed, or disconnected state.

[0113] As shown in Figure 16, when the system main relay S3 is closed, regardless of the state of other bypass units B, the + terminal T of the disconnect switch S1 is closed in the disconnected bypass unit B. + and the negative terminal T - A potential difference is generated between it and the transistor T corresponding to the bypass unit B. NPN When this is turned ON, current flows between the collector and emitter. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to bypass unit B becomes Low.

[0114] Figure 17 is a circuit diagram showing the state of the contact state detection circuit D'' corresponding to the bypass unit B in the disconnected state when the system main relay S3 is open. In the state shown in this figure, the state of the other bypass unit B may be connected, bypassed, or disconnected.

[0115] As shown in Figure 17, when the system main relay S3 is open, the contact state detection circuit D'' corresponding to the bypass unit B in the closed state becomes open, regardless of the state of other bypass units B. Therefore, in the contact state detection circuit D'', transistor T NPN The switch turns OFF, and no current flows between the collector and emitter. In this state, the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B in the OFF state becomes High.

[0116] Figure 18 is a flowchart illustrating the contact state confirmation process during bypass control execution of the energy storage system 21 shown in Figure 13. The process shown in this flowchart is initiated when the string controller StC receives a bypass control switch switching signal from the system controller SysC.

[0117] First, the string controller StC opens the system main relay S3 (step S201). If the system main relay S3 is open at the start of processing, it remains open.

[0118] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B with the bypass switch S2 open is High (step S202). In step S202, the string controller StC determines whether the bypass switch S2 is open or closed by referring to the control information stored in memory.

[0119] Here, as shown in Figures 15 and 17, when the system main relay S3 is open, no current flows to the contact state detection circuit D'' corresponding to the bypass unit B when the bypass switch S2 is open. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D'' becomes high. Therefore, if the bypass switch S2 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S202.

[0120] If a negative determination is made in step S202, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning bypass switch S2 (step S213). Conversely, if a positive determination is made in step S202, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B that is closed by the bypass switch S2 is Low (step S203). In step S203, the string controller StC determines whether the bypass switch S2 is open or closed by referring to the control information stored in memory.

[0121] Here, as shown in Figure 14, the contact state detection circuit D'' corresponding to the bypass unit B in the bypass state detects the transistor T regardless of the state of the system main relay S3 and other bypass units B. NPN Current flows through it. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D'' becomes Low. Therefore, if the bypass switch S2 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S203.

[0122] If a negative determination is made in step S203, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning bypass switch S2 (step S213). Conversely, if a positive determination is made in step S203, the string controller StC closes the system main relay S3 (step S204).

[0123] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B with the cutoff switch S1 open is Low (step S205). In step S205, the string controller StC determines whether the cutoff switch S1 is open or closed by referring to the control information stored in memory.

[0124] Here, when the system main relay S3 is closed, current flows in the contact state detection circuit D'' corresponding to the bypass unit B where the cutoff switch S1 is open, regardless of the state of the other bypass units B (see Figures 14 and 16). In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D'' becomes Low. Therefore, if the cutoff switch S1 is operating normally in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S205.

[0125] If a negative determination is made in step S205, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning cutoff switch S1 (step S213). Conversely, if an affirmative determination is made in step S205, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU corresponding to the bypass unit B that is closed for the cutoff switch S1 is High (step S206). In step S206, the string controller StC determines whether the cutoff switch S1 is Open / Close by referring to the control information stored in memory.

[0126] Here, as shown in Figure 15, when the system main relay S3 is closed, regardless of the state of other bypass units B, no current flows in the contact state detection circuit D'' corresponding to bypass unit B where the bypass switch S2 is open and the cutoff switch S1 is closed. In this case, the logic value of the input terminal IN in the corresponding microcontroller MCU becomes high. Therefore, if the cutoff switch S1 is operating normally in response to the switch switching signal, the string controller StC makes a positive determination in step S206.

[0127] If a negative determination is made in step S206, the string controller StC sends an abnormal notification signal for the malfunctioning cutoff switch S1 to the system controller SysC (step S213). Conversely, if a positive determination is made in step S206, the string controller StC sends a switch switching signal to the module controller MC corresponding to the cutoff switch S1 that is the target of bypass control, to open the cutoff switch S1 that is the target of bypass control for the battery module M (step S207).

[0128] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be bypassed is Low (step S208).

[0129] Here, as shown in Figure 16, when the system main relay S3 is closed, regardless of the state of other bypass units B, current flows in the contact state detection circuit D'' corresponding to the bypass unit B where both the bypass switch S2 and the cutoff switch S1 are open. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D'' becomes Low. Therefore, if the cutoff switch S1 is successfully switched to Open in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S208.

[0130] If a negative determination is made in step S208, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning cutoff switch S1 (step S213). Conversely, if a positive determination is made in step S208, the string controller StC opens the system main relay S3 (step S209).

[0131] Next, the string controller StC sends a switch switching signal to the module controller MC corresponding to the bypass switch S2 that is to be bypassed, to close the bypass switch S2 that is to be bypassed (step S210).

[0132] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be bypassed is Low (step S211).

[0133] Here, as shown in Figure 14, current flows through the contact state detection circuit D'' corresponding to bypass unit B where the bypass switch S2 is Close and the cutoff switch S1 is Open. At this time, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D'' becomes Low. Therefore, if the bypass switch S2 is successfully switched to Close in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S211.

[0134] If a negative result is obtained in step S211, the string controller StC sends an abnormal notification signal to the system controller SysC regarding the malfunctioning bypass switch S2 (step S213). Conversely, if a positive result is obtained in step S211, the string controller StC closes the system main relay S3 (step S212). This completes the process.

[0135] Figure 19 is a flowchart illustrating the contact state confirmation process during connection control execution of the energy storage system 21 shown in Figure 13. The process shown in this flowchart is started when the string controller StC receives a connection control switch switching signal from the system controller SysC. Note that the processes in steps S201 to S206 and S213 are the same as steps S201 to S206 and S213 of the contact state confirmation process during bypass control execution, so their explanation is omitted.

[0136] If a positive determination is made in step S206, the string controller StC opens the system main relay S3 (step S307). Next, the string controller StC sends a switch switching signal to the module controller MC corresponding to the bypass switch S2 that corresponds to the battery module M to be controlled, to open the bypass switch S2 (step S308).

[0137] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be controlled is High (step S309).

[0138] Here, as shown in Figure 17, when the system main relay S3 is open, no current flows through the contact state detection circuit D'' corresponding to the bypass unit B where both the bypass switch S2 and the cutoff switch S1 are open. In this case, the logic value of the input terminal IN in the microcontroller MCU corresponding to the contact state detection circuit D'' becomes high. Therefore, if the bypass switch S2 is successfully switched to open in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S309.

[0139] If a negative determination is made in step S309, the string controller StC sends an abnormal notification signal for the malfunctioning bypass switch S2 to the system controller SysC (step S213). Conversely, if a positive determination is made in step S309, the string controller StC closes the system main relay S3 (step S310). Next, the string controller StC sends a switch switching signal to the module controller MC corresponding to the bypass unit B to close the disconnection switch S1 corresponding to the battery module M that is the target of connection control (step S311).

[0140] Next, the string controller StC determines whether the logic value of the input terminal IN of the microcontroller MCU in the module controller MC corresponding to the battery module M to be controlled is High (step S312).

[0141] Here, as shown in Figure 15, regardless of the state of the system main relay S3 and other bypass units B, no current flows through the contact state detection circuit D'' corresponding to the bypass unit B where the bypass switch S2 is Open and the cutoff switch S1 is Closed. In this case, the logic value of the input terminal IN of the microcontroller MCU corresponding to the contact state detection circuit D'' becomes High. Therefore, if the cutoff switch S1 is successfully switched to Close in response to the switch switching signal, the string controller StC makes an affirmative judgment in step S312.

[0142] If a negative determination is made in step S312, the string controller StC sends an abnormal notification signal regarding the malfunctioning cutoff switch S1 to the system controller SysC (step S213). Conversely, if a positive determination is made in step S312, the process terminates.

[0143] As described above, in the power storage system 21 according to the present embodiment, the contact state detection circuit D” includes a resistor R2 which is a current limiting resistor, an NPN type transistor T which is a switching element, and a resistor R1 which is a pull-up resistor. The resistor R2 is connected to the - side terminal T of the cutoff switch S1. The base of the transistor T is connected to the resistor R2. The emitter of the transistor T is connected to the + side terminal T of the cutoff switch S1 and the ground GND. The collector of the transistor T is connected to the input terminal IN. The resistor R1 is connected to the collector of the transistor T, the input terminal IN, and the power supply Vcc. NPN When there is no potential difference between the + side terminal T and the - side terminal T of the cutoff switch S1, no current flows through the contact state detection circuit D”. When a potential difference occurs between the + side terminal T and the - side terminal T of the cutoff switch S1, current flows through the contact state detection circuit D”. When the transistor T of the contact state detection circuit D” is in the OFF state, no potential difference occurs between the input terminal IN of the microcontroller MCU and the ground terminal. When the transistor T is turned ON by current or voltage, a potential difference occurs between the input terminal IN of the microcontroller MCU and the ground terminal. Therefore, the string controller StC can determine the Open / Close of the cutoff switch S1 and the bypass switch S2 according to the potential difference between the input terminal IN of the microcontroller MCU and the ground terminal, and the control information of the cutoff switch S1, the bypass switch S2, and the system main relay S3. - NPN NPN + NPN NPN

[0144] + - + - NPN NPN

[0145] ​​​​​​​​​​​​​Although the present invention has been described above based on the embodiments described above, the present invention is not limited to the embodiments described above, and modifications may be made, or publicly known or well-known technologies may be combined as appropriate, without departing from the spirit of the present invention.

[0146] For example, in the above embodiment, the switching element that switches by voltage or current is a PNP type transistor T PNP or NPN type transistor T NPN However, other switching elements such as photocouplers can also be used as the switching element.

[0147] Furthermore, a rectifier circuit may be provided between the bypass unit B and the contact state detection circuits D, D', D'', or an insulating element such as a digital isolator may be provided between the contact state detection circuits D, D', D'' and the microcontroller MCU.

[0148] Furthermore, it is not mandatory to provide a microcontroller (MCU) for each battery module (M); the number of microcontrollers can be reduced by integrating multiple MCUs. [Explanation of symbols]

[0149] 1: Energy storage system 11: Energy storage system 21: Energy storage system 100: Battery control device (control unit) B1~Bn, B: Bypass unit (bypass section) D1~Dn, D: Contact state detection circuit (circuit) D1'~Dn', D': Contact state detection circuit (circuit) D1"~Dn",D": Contact state detection circuit (circuit) GND: Ground IN: Input terminal M1~Mn, M: Battery module (battery) MCU: Microcontroller (sensing unit) R1: Resistor (pull-down resistor, pull-up resistor) R2: Resistor (current limiting resistor) R3: Resistor (base-emitter resistance) S1: Disconnection switch (first switch) S2: Bypass switch (second switch) S3: System main relay (3rd switch) StC: String Controller (Control Unit) STR: Energy Storage String T + :+ side terminal (second terminal) T - :-side terminal (first terminal) T PNP : Transistor (switching element) T NPN : Transistor (switching element) ZD: Zener diode Vcc: power supply ΔV: predetermined value

Claims

1. A storage system comprising a storage string in which multiple storage batteries are connected in series, The system comprises a first switch connected in series with the battery, and a second switch connected in parallel with the first switch and the battery, and includes a plurality of bypass sections that can be set to one of the following states: a connected state where the first switch is closed and the second switch is open, a bypass state where the first switch is open and the second switch is closed, and a disconnected state where both the first and second switches are open. A third switch for connecting or disconnecting the aforementioned energy storage string, A circuit is provided in which a first terminal located on the battery side of the first switch is connected to a second terminal of the first switch, and current flows from the battery side or does not flow depending on the potential difference between the first terminal and the second terminal, A detection unit comprising an input terminal connected to the circuit and a ground terminal, wherein the potential difference between the input terminal and the ground terminal changes when current flows through the circuit and when no current flows through the circuit, A control unit that controls the first switch, the second switch, and the third switch. Equipped with, The control unit determines whether the first switch and the second switch are in an open state or a closed state based on the potential difference between the input terminal and the ground terminal of the detection unit and control information for controlling the first switch, the second switch, and the third switch.

2. The aforementioned circuit is The current limiting resistor connected to the first terminal, A Zener diode is provided, with its cathode connected to the current-limiting resistor and the input terminal, and its anode connected to the second terminal and ground. A pull-down resistor connected to the input terminal and the ground. The energy storage system according to claim 1, comprising:

3. The aforementioned circuit is The current limiting resistor connected to the first terminal, A switching element connected to the current limiting resistor and the input terminal, which switches according to current or voltage, The switching element and the pull-down resistor or pull-up resistor connected to the input terminal The energy storage system according to claim 1, comprising:

4. The switching element is a PNP type transistor in which the base is connected to the current limiting resistor, the emitter is connected to the power supply, and the collector is connected to the input terminal. The pull-down resistor connected to the collector, the second terminal, the input terminal, and ground, A base-emitter resistor connected to the base and the emitter The energy storage system according to claim 3, comprising:

5. The switching element is an NPN type transistor in which the base is connected to the current limiting resistor, the emitter is connected to the second terminal and ground, and the collector is connected to the input terminal. The pull-up resistor connected to the collector, the input terminal, and the power supply, A base-emitter resistor connected to the base and the emitter The energy storage system according to claim 3, comprising:

6. The control unit, In the state in which the third switch is controlled to the closed state, In the detection unit corresponding to the bypass section, where the state of the second switch according to the control information is open or closed and the state of the first switch according to the control information is open, if the potential difference between the input terminal and the ground terminal is greater than or equal to a predetermined value, the detection unit determines that the first switch corresponding to the detection unit is open. The energy storage system according to claim 2 or 4, in the detection unit corresponding to the bypass section, where the state of the second switch according to the control information is open and the state of the first switch according to the control information is closed, the detection unit determines that the first switch corresponding to the detection unit is closed when the potential difference between the input terminal and the ground terminal is less than the predetermined value.

7. The control unit, In the state in which the third switch is controlled to the closed state, In the detection unit corresponding to the bypass section, where the state of the second switch according to the control information is open or closed and the state of the first switch according to the control information is open, if the potential difference between the input terminal and the ground terminal is less than a predetermined value, the detection unit determines that the first switch corresponding to the detection unit is open. The energy storage system according to claim 5, in the detection unit corresponding to the bypass section in which the state of the second switch according to the control information is open and the state of the first switch according to the control information is closed, if the potential difference between the input terminal and the ground terminal is greater than or equal to the predetermined value, the detection unit determines that the first switch corresponding to the detection unit is in a closed state.

8. The control unit, In the state in which the third switch is controlled to the open state, In the detection unit corresponding to the bypass section, where the state of the second switch according to the control information is open and the state of the first switch according to the control information is open or closed, if the potential difference between the input terminal and the ground terminal is less than a predetermined value, the detection unit determines that the second switch corresponding to the detection unit is in an open state. The energy storage system according to claim 2 or 4, in the detection unit corresponding to the bypass section, where the state of the second switch according to the control information is closed and the state of the first switch according to the control information is open, the detection unit determines that the second switch corresponding to the detection unit is closed when the potential difference between the input terminal and the ground terminal is greater than or equal to the predetermined value.

9. The control unit, In the state in which the third switch is controlled to the open state, In the detection unit corresponding to the bypass section, where the state of the second switch according to the control information is open and the state of the first switch according to the control information is open or closed, if the potential difference between the input terminal and the ground terminal is greater than or equal to a predetermined value, the detection unit determines that the second switch corresponding to the detection unit is in an open state. The energy storage system according to claim 5, in the detection unit corresponding to the bypass section in which the state of the second switch according to the control information is closed and the state of the first switch according to the control information is open, if the potential difference between the input terminal and the ground terminal is less than the predetermined value, the detection unit determines that the second switch corresponding to the detection unit is in a closed state.

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