Bypass circuit and power storage system

Abstract

To reliably prevent short-circuits at the time of operation of a bypass circuit in a power storage system having a plurality of storage batteries connected in series and the bypass circuit bypassing the storage batteries.SOLUTION: Bypass circuits B1-Bn provided in a power storage system 1 having a plurality of storage battery modules M1-Mn connected in series and bypassing the storage battery modules M1-Mn have a shutdown switch S1 provided between the storage battery modules M1-Mn adjacent to each other and switching by a shutdown signal outputted from a relay driver 102, a bypass line BL bypassing the shutdown switch S1 and the storage battery modules M1-Mn, a bypass switch S2 provided in the bypass line BL and switching by a bypass signal outputted from the relay driver 102, and a safety switch S3 preventing both the shutdown switch S1 and the bypass switch S2 from being in a closed state concurrently.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bypass circuit and a power storage system. [Background technology]

[0002] A system for controlling discharging of a power storage system in which multiple storage batteries are connected in series is known that bypasses a storage battery that cannot discharge the required current and discharges from the other storage batteries (see, for example, Patent Document 1). Also, a system for controlling charging of a power storage system in which multiple storage batteries are connected in series is known that bypasses a storage battery that cannot charge the input current and charges the other storage batteries (see, for example, Patent Document 2). The power storage systems described in Patent Documents 1 and 2 include a first switch that connects or disconnects the storage batteries, and a second switch that connects or disconnects the bypass line. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-31247 A [Patent Document 2] JP 2013-31249 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the energy storage systems described in Patent Documents 1 and 2, in order to prevent short circuits, it is necessary to observe the operation sequence and operation interval of the first switch and the second switch in the operation of bypassing the storage battery or the operation of releasing the bypass state of the storage battery. Specifically, in the operation of bypassing the storage battery, the control unit must output a control signal for switching the first switch to a cut-off state, and then output a control signal for switching the second switch to a connected state after a sufficient time has elapsed for the first switch to be switched to the cut-off state. In addition, in the operation of releasing the bypass state of the storage battery, the control unit must output a control signal for switching the second switch to a cut-off state, and then output a control signal for switching the first switch to a connected state after a sufficient time has elapsed for the second switch to be switched to the cut-off state. However, due to a malfunction of the control unit, it is possible that the operation sequence and operation interval of the first switch and the second switch will not be observed.

[0005] In view of the above circumstances, an object of the present invention is to provide a bypass circuit and a power storage system that can reliably prevent a short circuit during operation of the bypass circuit in a power storage system including a plurality of storage batteries connected in series and a bypass circuit that bypasses the storage batteries. [Means for solving the problem]

[0006] The bypass circuit of the present invention is provided in an electricity storage system having a plurality of storage batteries connected in series, and is a bypass circuit for bypassing the storage batteries, the bypass circuit comprising: a first switch provided between adjacent storage batteries and opened and closed by a first control signal output from a control circuit; a bypass line bypassing the first switch and the storage batteries; a second switch provided in the bypass line and opened and closed by a second control signal output from the control circuit; and a co-closure prevention means for preventing the first switch and the second switch from being both closed. a first signal line for transmitting the first control signal output from the control circuit to the first switch; and a second signal line for transmitting the second control signal output from the control circuit to the second switch. Equipped with The co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a closed state at the same time, and the third switch includes a first contact provided on the second signal line and a drive unit that is operated by the first control signal to open and close the first contact, and the first contact opens when the first switch is in a closed state to interrupt the second signal line. do. The bypass circuit of the present invention is provided in an electricity storage system having a plurality of storage batteries connected in series, and is a bypass circuit for bypassing the storage batteries, the bypass circuit comprising: a first switch provided between adjacent storage batteries and opened and closed by a first control signal output from a control circuit; a bypass line bypassing the first switch and the storage batteries; a second switch provided in the bypass line and opened and closed by a second control signal output from the control circuit; co-closure prevention means for preventing the first switch and the second switch from being both closed; a first signal line for transmitting the first control signal output from the control circuit to the first switch; and a second signal line for transmitting the second control signal output from the control circuit to the second switch, the co-closure prevention means comprising a third switch for preventing the first switch and the second switch from being both closed, the third switch comprising a first contact provided in the first signal line and a drive unit operated by the second control signal for opening and closing the first contact, the first contact opens when the second switch is closed to interrupt the first signal line. The bypass circuit of the present invention is provided in an electricity storage system having a plurality of storage batteries connected in series, and is a bypass circuit for bypassing the storage batteries, the bypass circuit including a first switch provided between adjacent storage batteries and opened and closed by a first control signal output from a control circuit, a bypass line bypassing the first switch and the storage batteries, a second switch provided in the bypass line and opened and closed by a second control signal output from the control circuit, co-closure prevention means for preventing the first switch and the second switch from being both closed, a first signal line for transmitting the first control signal output from the control circuit to the first switch, and a bypass line for transmitting the first control signal output from the control circuit to the first switch. and a second signal line that transmits the second control signal output from the first switch to the second switch, and the co-closure prevention means comprises a third switch that prevents the first switch and the second switch from being both closed, and the third switch comprises a first contact provided on the second signal line, a detection unit that detects an open state of the first switch, and a drive unit that operates in response to a detection signal from the detection unit to open and close the first contact, and the first contact opens to interrupt the second signal line when the detection unit does not detect an open state of the first switch, and closes to connect the second signal line when the detection unit detects an open state of the first switch. The bypass circuit of the present invention is provided in an electricity storage system having a plurality of storage batteries connected in series, and is a bypass circuit for bypassing the storage batteries, the bypass circuit comprising: a first switch provided between adjacent storage batteries and opened and closed by a first control signal output from a control circuit; a bypass line bypassing the first switch and the storage batteries; a second switch provided in the bypass line and opened and closed by a second control signal output from the control circuit; co-closure prevention means for preventing the first switch and the second switch from both being closed; a first signal line for transmitting the first control signal output from the control circuit to the first switch; and a second signal line for transmitting the second control signal output from the control circuit to the second switch, the co-closure prevention means comprising a detection unit for detecting an open state of the first switch, and an output control unit for determining whether or not to output the second control signal in accordance with the detection signal of the detection unit, and the second control signal is not output when the detection unit does not detect an open state of the first switch, and is output when the detection unit detects an open state of the first switch.

[0007] The power storage system of the present invention is a power storage system including a plurality of storage batteries connected in series and a bypass circuit for bypassing the storage batteries, the bypass circuit including a first switch provided between adjacent storage batteries and opened and closed by a first control signal output from a control circuit, a bypass line bypassing the first switch and the storage batteries, a second switch provided in the bypass line and opened and closed by a second control signal output from the control circuit, and a co-close prevention means for preventing the first switch and the second switch from being both closed. a first signal line for transmitting the first control signal output from the control circuit to the first switch; and a second signal line for transmitting the second control signal output from the control circuit to the second switch. Equipped with The co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a closed state at the same time, and the third switch includes a first contact provided on the second signal line and a drive unit that is operated by the first control signal to open and close the first contact, and the first contact opens when the first switch is in a closed state to interrupt the second signal line. do. The power storage system of the present invention is a power storage system including a plurality of storage batteries connected in series and a bypass circuit that bypasses the storage batteries, the bypass circuit including a first switch provided between adjacent storage batteries and opened and closed by a first control signal output from a control circuit, a bypass line that bypasses the first switch and the storage batteries, a second switch provided in the bypass line and opened and closed by a second control signal output from the control circuit, a co-closure prevention means that prevents the first switch and the second switch from being both closed, a first signal line that transmits the first control signal output from the control circuit to the first switch, and a second signal line that transmits the second control signal output from the control circuit to the second switch, the co-closure prevention means including a third switch that prevents the first switch and the second switch from being both closed, the third switch including a first contact provided in the first signal line and a drive unit that is operated by the second control signal to open and close the first contact, the first contact opens when the second switch is closed to interrupt the first signal line. Effect of the Invention

[0008] According to the present invention, in an electricity storage system including a plurality of storage batteries connected in series and a bypass circuit for bypassing the storage batteries, it is possible to reliably prevent a short circuit during operation of the bypass circuit. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. [Diagram 3] FIG. 3 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. [Figure 4] FIG. 4 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. [Diagram 5] FIG. 5 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. [Figure 6] FIG. 6 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. [Figure 7]FIG. 7 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. [Figure 8] FIG. 8 is a circuit diagram showing an outline of a power storage system including a bypass circuit according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and the embodiments can be appropriately modified within the scope of the present invention. In addition, in the embodiments shown below, some configurations are omitted from illustration and description, but for the details of the omitted technologies, publicly known or well-known technologies are appropriately applied within the scope of not causing any contradiction with the contents described below.

[0011] 1 is a circuit diagram showing an outline of a power storage system 1 including bypass circuits B1 to Bn according to one embodiment of the present invention. The power storage system 1 shown in the figure is a stationary or vehicle-mounted power source, and includes a storage battery string 10 and a control unit 100. The storage battery string 10 is connected to a load or a charge / discharge circuit 11.

[0012] The storage battery string 10 includes n (n is an integer of 2 or more) storage battery modules M1 to Mn connected in series. Although not particularly limited, the storage battery string 10 of this embodiment is a regenerated second-hand storage battery, and the storage battery modules M1 to Mn have different degrees of deterioration. The storage battery modules M1 to Mn are, for example, secondary batteries such as lithium ion batteries and lithium ion capacitors.

[0013] The positive electrode of the starting storage battery module M1 and the negative electrode of the terminal storage battery module Mn are connected to a load or charge / discharge circuit 11. The storage battery modules M1 to Mn are charged by receiving power from the load or charge / discharge circuit 11, and discharge the charged power to supply power to the load or charge / discharge circuit 11.

[0014] The load or charge / discharge circuit 11 includes a load, a generator, a power converter, etc. When the power storage system 1 is for stationary use, household appliances, commercial power supply systems, liquid crystal displays, communication modules, etc. are the loads, and a solar power generation system, etc. is the generator. On the other hand, when the power storage system 1 is for vehicle use, a drive motor, an air conditioner, various vehicle electrical equipment, etc. are the loads. The drive motor is both a load and a generator.

[0015] The battery string 10 may include n storage battery cells or storage battery packs connected in series, instead of the n storage battery modules M1 to Mn connected in series. The power storage system 1 may include a bypass circuit that bypasses each storage battery cell or each storage battery pack.

[0016] The power storage system 1 includes n bypass circuits B1 to Bn, each of which is provided for each of the storage battery modules M1 to Mn. Each of the bypass circuits B1 to Bn includes a bypass line BL, a shutoff signal line SL1, a bypass signal line SL2, a shutoff switch S1, a bypass switch S2, and a safety switch S3.

[0017] The cutoff switch S1 is provided between the positive electrode of each of the storage battery modules M1 to Mn and one end of the bypass line BL. Examples of the cutoff switch S1 include a relay and a semiconductor switch. The cutoff switch S1 in this embodiment is a relay and includes a b-contact and a coil CR1.

[0018] The b-contact of the cutoff switch S1 is provided on a power line connecting adjacent storage battery modules M1-Mn. The coil CR1 of the cutoff switch S1 is provided on a cutoff signal line SL1. When a signal current is output from the relay driver 102 of the control unit 100 to the coil CR1 of the cutoff switch S1 through the cutoff signal line SL1, the b-contact of the cutoff switch S1 opens, and the corresponding storage battery module M1-Mn enters a cutoff state.

[0019] The bypass line BL is a power line that bypasses the corresponding storage battery modules M1 to Mn and the cutoff switch S1. The bypass switch S2 is provided on the bypass line BL. Examples of the bypass switch S2 include a relay and a semiconductor switch. The bypass switch S2 in this embodiment is a relay, and includes an a-contact and a coil CR2.

[0020] The a-contact of the bypass switch S2 is provided on the bypass line BL, and the coil CR2 of the bypass switch S2 is provided on the bypass signal line SL2. When a signal current is output from the relay driver 102 of the control unit 100 to the coil CR2 of the bypass switch S2 through the bypass signal line SL2, the a-contact of the bypass switch S2 closes and the bypass line BL is brought into a connected state.

[0021] When the cutoff switch S1 is in the connected state and the bypass switch S2 is in the cutoff state in all of the bypass circuits B1 to Bn, all of the storage battery modules M1 to Mn are connected in series to the load or the charge / discharge circuit 11. On the other hand, when the cutoff switch S1 is in the cutoff state and the bypass switch S2 is in the connected state in any of the bypass circuits B1 to Bn, the storage battery modules M1 to Mn corresponding to that bypass circuit B1 to Bn are bypassed.

[0022] The control unit 100 includes an MCU (Micro Controller Unit) 101, a relay driver 102, and n safety switches S3. The MCU 101 monitors and controls each of the storage battery modules M1 to Mn and performs switching control of each of the bypass circuits B1 to Bn. The relay driver 102 outputs a signal current for energizing a coil CR1 of the cutoff switch S1 to a cutoff signal line SL1 in accordance with a command from the MCU 101. The relay driver 102 also outputs a signal current for energizing a coil CR2 of the bypass switch S2 to a bypass signal line SL2.

[0023] The safety switch S3 is provided for each of the storage battery modules M1 to Mn. Examples of the safety switch S3 include a relay, a semiconductor switch, etc. The safety switch S3 in this embodiment is a relay, and includes an a-contact and a coil CR3.

[0024] The a-contact of the safety switch S3 is provided on the bypass signal line SL2, and the coil CR3 of the safety switch S3 is connected to the cutoff signal line SL1. When the relay driver 102 outputs a signal current to the coil CR1 of the cutoff switch S1 through the cutoff signal line SL1, the signal current is also output to the coil CR3 of the safety switch S3. When the relay driver 102 outputs a signal current to the coil CR3 of the safety switch S3, the a-contact of the safety switch S3 closes, the bypass signal line SL2 is connected, and the signal current can be output from the relay driver 102 to the coil CR2 of the bypass switch S2. On the other hand, when the relay driver 102 does not output a signal current to the coil CR1 of the cutoff switch S1, the signal current is not output to the coil CR3 of the safety switch S3 either, and the signal current cannot be output from the relay driver 102 to the coil CR2 of the bypass switch S2.

[0025] That is, during the period when no signal current is output from the relay driver 102 to the coil CR1 of the cutoff switch S1, the bypass signal line SL2 is interrupted by the safety switch S3, and a state in which a signal current cannot be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained. Then, during the period when a signal current is output from the relay driver 102 to the coil CR1 of the cutoff switch S1, the bypass signal line SL2 is connected by the safety switch S3, and a state in which a signal current can be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained.

[0026] When performing a bypass operation to bypass the storage battery modules M1 to Mn using the bypass circuits B1 to Bn, the relay driver 102 first outputs a signal current to the coil CR1 of the cutoff switch S1, and then outputs the signal current to the coil CR2 of the bypass switch S2. That is, the relay driver 102 first switches the cutoff switch S1 to the cut-off state, and then switches the bypass switch S2 to the connect state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when performing the bypass operation.

[0027] Here, consider a situation in which the timing of output of a signal current (hereinafter sometimes referred to as a cutoff signal) for switching the cutoff switch S1 to the cutoff state and a signal current (hereinafter sometimes referred to as a bypass signal) for switching the bypass switch S2 to the connect state is reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to output a bypass signal prior to output of the cutoff signal in accordance with a command from the MCU 101. However, at the timing of output of the bypass signal, the bypass signal line SL2 is cut off by the safety switch S3, so that the output of the bypass signal to the coil CR2 of the bypass switch S2 is not realized. Therefore, even if the MCU 101 malfunctions, the a-contact of the bypass switch S2 will not close when the b-contact of the cutoff switch S1 is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0028] On the other hand, when a bypass release operation is performed in which the bypass circuits B1-Bn release the bypass state of the storage battery modules M1-Mn, the relay driver 102 first stops the output of the signal current to the coil CR2 of the bypass switch S2, and then stops the output of the signal current to the coil CR1 of the cutoff switch S1. That is, the relay driver 102 first switches the bypass switch S2 to the cutoff state, and then switches the cutoff switch S1 to the connect state. This prevents a short circuit of the storage battery modules M1-Mn through the bypass line BL when the bypass release operation is performed.

[0029] Here, consider a situation in which the timing of stopping the output of the bypass signal and the output of the cutoff signal are reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to stop the output of the cutoff signal before stopping the output of the bypass signal, following a command from the MCU 101. In this case, the output of the cutoff signal stops the output of the signal current to the coil CR3 of the safety switch S3 due to the stop of the output of the cutoff signal, and the output of the bypass signal is also stopped. Therefore, even if the MCU 101 malfunctions, the b-contact of the cutoff switch S1 will not close while the a-contact of the bypass switch S2 is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0030] Here, by providing the safety switch S3 in the control unit 100 rather than in the storage battery string 10, the wiring within the storage battery string 10 can be configured simply.

[0031] The b-contact of the cutoff switch S1 may be replaced with an a-contact, the a-contact of the bypass switch S2 with a b-contact, and the a-contact of the safety switch S3 with a b-contact. In this case, when the corresponding storage battery modules M1-Mn are connected, a signal current may be output to the coil CR1 of the cutoff switch S1, the coil CR2 of the bypass switch S2, and the coil CR3 of the safety switch S3. Also, when the corresponding storage battery modules M1-Mn are bypassed, no signal current may be output to the coil CR1 of the cutoff switch S1, the coil CR2 of the bypass switch S2, and the coil CR3 of the safety switch S3.

[0032] 2 is a circuit diagram showing an outline of a power storage system 2 including bypass circuits B1-Bn according to another embodiment of the present invention. The power storage system 2 of this embodiment differs from the power storage system 1 of the above embodiment in the configurations of the bypass circuits B1-Bn, in particular, the configurations of the cutoff switch S1 and the safety switch S3.

[0033] The bypass circuits B1 to Bn of this embodiment include a bypass line BL, a shutoff signal line SL1, a bypass signal line SL2, a shutoff switch S1, a bypass switch S2, and a safety switch S3. The configurations of the bypass line BL and the bypass switch S2 are similar to those of the power storage system 1 of the above-described embodiment.

[0034] The n cutoff switches S1 are provided for each of the storage battery modules M1 to Mn. Examples of the cutoff switches S1 include relays, semiconductor switches, etc. The cutoff switch S1 of this embodiment is a relay, and includes an a-contact and a coil CR1.

[0035] The contact a of the cutoff switch S1 is provided on the power line of the storage battery string 10, and the coil CR1 of the cutoff switch S1 is provided on the cutoff signal line SL1. When a signal current is output from the relay driver 102 to the coil CR1 of the cutoff switch S1 through the cutoff signal line SL1, the contact a of the cutoff switch S1 closes and the corresponding storage battery modules M1 to Mn are brought into a connected state.

[0036] The n safety switches S3 are provided for each of the storage battery modules M1 to Mn in the control unit 100. Examples of the safety switches S3 include relays, semiconductor switches, etc. The safety switch S3 in this embodiment is a relay, and includes a b-contact and a coil CR3.

[0037] The b-contact of the safety switch S3 is provided on the cutoff signal line SL1, and the coil CR3 of the safety switch S3 is connected to the bypass signal line SL2. When the relay driver 102 outputs a signal current to the coil CR2 of the bypass switch S2 through the bypass signal line SL2, the signal current is also output to the coil CR3 of the safety switch S3. When the signal current is output from the relay driver 102 to the coil CR3 of the safety switch S3, the b-contact of the safety switch S3 opens, the cutoff signal line SL1 is in a cutoff state, and the output of the signal current from the relay driver 102 to the coil CR1 of the cutoff switch S1 is disabled. On the other hand, when the signal current is not output from the relay driver 102 to the coil CR2 of the bypass switch S2, the signal current is not output to the coil CR3 of the safety switch S3 either, the b-contact of the safety switch S3 is closed, the cutoff signal line SL1 is in a connected state, and the output of the signal current from the relay driver 102 to the coil CR1 of the cutoff switch S1 is enabled.

[0038] That is, during the period when a signal current is output from the relay driver 102 to the coil CR2 of the bypass switch S2, the cutoff signal line SL1 is cut off by the safety switch S3, and a state is maintained in which a signal current cannot be output from the relay driver 102 to the coil CR1 of the cutoff switch S1. Then, during the period when a signal current is not output from the relay driver 102 to the coil CR2 of the bypass switch S2, the cutoff signal line SL1 is connected by the safety switch S3, and a state in which a signal current can be output from the relay driver 102 to the coil CR1 of the cutoff switch S1 is maintained.

[0039] When the bypass circuits B1 to Bn perform the bypass operation, the relay driver 102 first stops outputting the signal current to the coil CR1 of the cutoff switch S1, and then outputs the signal current to the coil CR2 of the bypass switch S2. That is, the relay driver 102 first switches the cutoff switch S1 to the cut-off state, and then switches the bypass switch S2 to the connect state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when the bypass operation is performed.

[0040] Here, consider a situation in which the timing of stopping output of the shutdown signal and starting output of the bypass signal is reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to start output of the bypass signal before stopping output of the shutdown signal, in accordance with a command from the MCU 101. However, at the timing when output of the bypass signal starts, the shutdown signal line SL1 is cut off by the safety switch S3, and output of the shutdown signal is stopped. Therefore, even if the MCU 101 malfunctions, the a-contact of the bypass switch S2 will not close when the a-contact of the shutdown switch S1 is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0041] On the other hand, when the bypass circuits B1 to Bn perform the bypass release operation, the relay driver 102 first stops outputting the signal current to the coil CR2 of the bypass switch S2, and then starts outputting the signal current to the coil CR1 of the cutoff switch S1. That is, the relay driver 102 first switches the bypass switch S2 to the cutoff state, and then switches the cutoff switch S1 to the connect state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when the bypass release operation is performed.

[0042] Here, consider a situation in which the timing of stopping the output of the bypass signal and starting the output of the cutoff signal is reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to start outputting the cutoff signal before stopping the output of the bypass signal, following a command from the MCU 101. In this case, the output of the bypass signal stops the output of the signal current to the coil CR3 of the safety switch S3 due to the stop of the output of the bypass signal, and the relay driver 102 cannot output a signal to the coil CR1 of the cutoff switch S1. Therefore, even if the MCU 101 malfunctions, the a-contact of the cutoff switch S1 will not close while the a-contact of the bypass switch S2 is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0043] Here, by providing the safety switch S3 in the control unit 100 rather than in the storage battery string 10, the wiring within the storage battery string 10 can be configured simply.

[0044] The a-contact of the cutoff switch S1 may be replaced with a b-contact, the a-contact of the bypass switch S2 with a b-contact, and the b-contact of the safety switch S3 with an a-contact. In this case, when the corresponding storage battery modules M1-Mn are connected, no signal current is output to the coil CR1 of the cutoff switch S1, and a signal current is output to the coil CR2 of the bypass switch S2 and the coil CR3 of the safety switch S3. Also, when the corresponding storage battery modules M1-Mn are bypassed, a signal current is output to the coil CR1 of the cutoff switch S1, and no signal current is output to the coil CR2 of the bypass switch S2 and the coil CR3 of the safety switch S3.

[0045] 3 is a circuit diagram showing an outline of a power storage system 3 including bypass circuits B1 to Bn according to another embodiment of the present invention. The power storage system 3 of this embodiment and the power storage system 1 of the above-mentioned embodiment differ in the configuration of the bypass circuits B1 to Bn. In particular, the power storage system 3 of this embodiment includes a cutoff switch S1' having the functions of a cutoff switch S1 and a safety switch S3, whereas the power storage system 1 of the above-mentioned embodiment includes a cutoff switch S1 and a safety switch S3, in that the configurations of the two differ.

[0046] The bypass circuits B1 to Bn of this embodiment include a bypass line BL, a cutoff signal line SL1, a bypass signal line SL2, a cutoff switch S1′, and a bypass switch S2. The configurations of the bypass line BL and the bypass switch S2 are similar to those of the power storage system 1 of the above-described embodiment.

[0047] The n cutoff switches S1' are provided for each of the storage battery modules M1 to Mn. Examples of the cutoff switches S1' include relays and semiconductor switches. The cutoff switch S1' in this embodiment is a relay, and includes an a-contact, a b-contact, and a coil CR1.

[0048] The b-contact of the cutoff switch S1' is provided on the power line of the storage battery string 10, and the a-contact of the cutoff switch S1' is provided on the bypass signal line SL2. The coil CR1 of the cutoff switch S1' is provided on the cutoff signal line SL1. When the relay driver 102 outputs a signal current to the coil CR1 of the cutoff switch S1' through the cutoff signal line SL1, the a-contact of the cutoff switch S1' is closed, the bypass signal line SL2 is connected, and the signal current can be output from the relay driver 102 to the coil CR2 of the bypass switch S2. On the other hand, when the signal current is not output from the relay driver 102 to the coil CR1 of the cutoff switch S1', the a-contact of the cutoff switch S1' is open, and the signal current cannot be output from the relay driver 102 to the coil CR2 of the bypass switch S2.

[0049] That is, during the period when no signal current is output from the relay driver 102 to the coil CR1 of the cutoff switch S1', the bypass signal line SL2 is interrupted by the a-contact of the cutoff switch S1', and a state in which a signal current cannot be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained. Then, during the period when a signal current is output from the relay driver 102 to the coil CR1 of the cutoff switch S1', the bypass signal line SL2 is connected by the a-contact of the cutoff switch S1', and a state in which a signal current can be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained.

[0050] When the bypass circuits B1 to Bn perform the bypass operation, the relay driver 102 first outputs a signal current to the coil CR1 of the cutoff switch S1', and then outputs the signal current to the coil CR2 of the bypass switch S2. That is, the relay driver 102 first switches the b-contact of the cutoff switch S1' to the cutoff state, and then switches the bypass switch S2 to the connect state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when the bypass operation is performed.

[0051] Here, consider a situation in which the timing of outputting the cutoff signal and the bypass signal is reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to start outputting the bypass signal before starting to output the cutoff signal, in accordance with a command from the MCU 101. However, at the timing of starting to output the bypass signal, the bypass signal line SL2 is cut off by the a-contact of the cutoff switch S1', so that no signal current is output from the relay driver 102 to the coil CR2 of the bypass switch S2. Therefore, even if the MCU 101 malfunctions, the a-contact of the bypass switch S2 will not close when the b-contact of the cutoff switch S1' is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0052] On the other hand, when the bypass circuits B1 to Bn perform the bypass release operation, the relay driver 102 first stops the output of the signal current to the coil CR2 of the bypass switch S2, and then stops the output of the signal current to the coil CR1 of the cutoff switch S1'. That is, the relay driver 102 first switches the bypass switch S2 to the cutoff state, and then switches the b contact of the cutoff switch S1' to the connected state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when the bypass release operation is performed.

[0053] Here, consider a situation in which the timing of stopping the output of the bypass signal and the output of the cutoff signal are reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to stop the output of the cutoff signal before stopping the output of the bypass signal, following a command from the MCU 101. In this case, the output of the cutoff signal stops the output of the signal current to the coil CR1 of the cutoff switch S1' due to the output of the cutoff signal being stopped, and the output of the bypass signal is also stopped. Therefore, even if the MCU 101 malfunctions, the b-contact of the cutoff switch S1' will not close while the a-contact of the bypass switch S2 is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0054] The b-contact of the cutoff switch S1' may be replaced with an a-contact, the a-contact of the cutoff switch S1' with a b-contact, and the a-contact of the bypass switch S2 with a b-contact. In this case, when the corresponding storage battery modules M1-Mn are connected, a signal current may be output to the coil CR1 of the cutoff switch S1' and the coil CR2 of the bypass switch S2. Also, when the corresponding storage battery modules M1-Mn are bypassed, no signal current may be output to the coil CR1 of the cutoff switch S1' and the coil CR2 of the bypass switch S2.

[0055] 4 is a circuit diagram showing an outline of a power storage system 4 including bypass circuits B1-Bn according to another embodiment of the present invention. The power storage system 4 of this embodiment differs from the power storage system 3 of the above embodiment in the configurations of the bypass circuits B1-Bn, in particular, the configurations of the cutoff switches S1, S1' and the bypass switches S2', S2.

[0056] The bypass circuits B1 to Bn of this embodiment include a bypass line BL, a cutoff signal line SL1, a bypass signal line SL2, a cutoff switch S1, and a bypass switch S2'. The configuration of the bypass line BL is similar to that of the power storage system 3 of the above-described embodiment.

[0057] The n cutoff switches S1 are provided for each of the storage battery modules M1 to Mn. Examples of the cutoff switches S1 include relays, semiconductor switches, etc. The cutoff switch S1 of this embodiment is a relay, and includes an a-contact and a coil CR1.

[0058] The contact a of the cutoff switch S1 is provided on the power line of the storage battery string 10, and the coil CR1 of the cutoff switch S1 is provided on the cutoff signal line SL1. When a signal current is output from the relay driver 102 to the coil CR1 of the cutoff switch S1 through the cutoff signal line SL1, the contact a of the cutoff switch S1 closes and the corresponding storage battery modules M1 to Mn are brought into a connected state.

[0059] The n bypass switches S2' are provided for each of the storage battery modules M1 to Mn. Examples of the bypass switches S2' include relays and semiconductor switches. The bypass switch S2' in this embodiment is a relay, and includes an a-contact, a b-contact, and a coil CR2.

[0060] The a-contact of the bypass switch S2' is provided on the bypass line BL, and the b-contact of the bypass switch S2' is provided on the cutoff signal line SL1. The coil CR2 of the bypass switch S2' is provided on the bypass signal line SL2. When a signal current is output from the relay driver 102 to the coil CR2 of the bypass switch S2' through the bypass signal line SL2, the b-contact of the bypass switch S2' opens, the cutoff signal line SL1 is in a cutoff state, and the output of the signal current from the relay driver 102 to the coil CR1 of the cutoff switch S1 is disabled. On the other hand, when no signal current is supplied from the relay driver 102 to the coil CR2 of the bypass switch S2', the b-contact of the bypass switch S2' is in a closed state, and the output of the signal current from the relay driver 102 to the coil CR2 of the cutoff switch S1 is enabled.

[0061] That is, during the period when a signal current is output from the relay driver 102 to the coil CR2 of the bypass switch S2', the cutoff signal line SL1 is cut off by the b-contact of the bypass switch S2', and a state in which a signal current cannot be output from the relay driver 102 to the coil CR1 of the cutoff switch S1 is maintained. Then, during the period when a signal current is not supplied from the relay driver 102 to the coil CR2 of the bypass switch S2', the cutoff signal line SL1 is connected by the b-contact of the bypass switch S2', and a state in which a signal current can be output from the relay driver 102 to the coil CR1 of the cutoff switch S1 is maintained.

[0062] When the bypass circuits B1 to Bn perform the bypass operation, the relay driver 102 first stops the supply of signal current to the coil CR1 of the cutoff switch S1, and then supplies the signal current to the coil CR2 of the bypass switch S2'. That is, the relay driver 102 first switches the cutoff switch S1 to the cut-off state, and then switches the bypass switch S2' to the connect state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when the bypass operation is performed.

[0063] Here, consider a situation in which the timing of stopping output of the shutdown signal and starting output of the bypass signal is reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to start output of the bypass signal before stopping output of the shutdown signal, in accordance with a command from the MCU 101. However, at the timing when output of the bypass signal starts, the shutdown signal line SL1 is cut off by the b-contact of the bypass switch S2', and output of the shutdown signal is stopped. Therefore, even if the MCU 101 malfunctions, the a-contact of the bypass switch S2' will not close when the a-contact of the shutdown switch S1 is closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0064] On the other hand, when the bypass circuits B1 to Bn perform the bypass release operation, the relay driver 102 first stops the output of the signal current to the coil CR2 of the bypass switch S2', and then starts the output of the signal current to the coil CR1 of the cutoff switch S1. That is, the control unit 100 first switches the bypass switch S2' to the cutoff state, and then switches the cutoff switch S1 to the connect state. This prevents a short circuit of the storage battery modules M1 to Mn through the bypass line BL when the bypass release operation is performed.

[0065] Here, consider a situation in which the timing of stopping the output of the bypass signal and starting the output of the cutoff signal is reversed due to a malfunction of the MCU 101. In such a situation, the relay driver 102 attempts to start outputting the cutoff signal before stopping the output of the bypass signal, in accordance with a command from the MCU 101. In this case, since the bypass signal is being output, the b-contact of the bypass switch S2' is in an open state, and it is impossible for the relay driver 102 to output a cutoff signal to the cutoff switch S1. Therefore, even if the MCU 101 malfunctions, the a-contact of the bypass switch S2' is closed and the a-contact of the cutoff switch S1 is not closed, and a short circuit of the storage battery modules M1 to Mn through the bypass line BL is reliably prevented.

[0066] The a-contact of the cutoff switch S1 may be replaced with a b-contact, the a-contact of the bypass switch S2' with a b-contact, and the b-contact of the bypass switch S2' with an a-contact. In this case, when the corresponding storage battery modules M1-Mn are connected, a signal current is not output to the coil CR1 of the cutoff switch S1, and a signal current is output to the coil CR2 of the bypass switch S2'. Also, when the corresponding storage battery modules M1-Mn are bypassed, a signal current is output to the coil CR1 of the cutoff switch S1, and a signal current is not output to the coil CR2 of the bypass switch S2'.

[0067] 5 is a circuit diagram showing an outline of a power storage system 5 including bypass circuits B1-Bn according to another embodiment of the present invention. The power storage system 5 of this embodiment differs from the power storage system 1 of the above-described embodiment in the configuration of the bypass circuits B1-Bn. In particular, the power storage system 5 of this embodiment has a safety switch S3 provided on the storage battery string 10 side, whereas the power storage system 1 of the above-described embodiment has a safety switch S3 provided on the control unit 100 side, which is a difference between the two configurations.

[0068] On the other hand, the energy storage system 5 of this embodiment and the energy storage system 1 of the above-described embodiment have a common configuration and function, except for the difference in whether the safety switch S3 is provided on the storage battery string 10 side or the control unit 100 side.

[0069] 6 is a circuit diagram showing an outline of a power storage system 6 including bypass circuits B1 to Bn according to another embodiment of the present invention. The power storage system 6 of this embodiment differs from the power storage system 2 of the above-described embodiment in the configuration of the bypass circuits B1 to Bn. In particular, the power storage system 6 of this embodiment has a safety switch S3 provided on the storage battery string 10 side, whereas the power storage system 2 of the above-described embodiment has a safety switch S3 provided on the control unit 100 side, which is a difference between the two configurations.

[0070] On the other hand, the energy storage system 6 of this embodiment and the energy storage system 2 of the above-described embodiment have a common configuration and function, except for the difference in whether the safety switch S3 is provided on the battery string 10 side or the control unit 100 side.

[0071] 7 is a circuit diagram showing an outline of a power storage system 7 including bypass circuits B1 to Bn according to another embodiment of the present invention. The power storage system 7 of this embodiment differs from the power storage system 1 of the above embodiment in the operating principle of the safety switch S3.

[0072] The safety switch S3 is provided for each of the storage battery modules M1 to Mn. Examples of the safety switch S3 include a relay, a semiconductor switch, etc. The safety switch S3 in this embodiment is a relay, and includes an a-contact, a coil CR3, and a detection circuit 700.

[0073] The a-contact of the safety switch S3 is provided on the bypass signal line SL2, and the coil CR3 of the safety switch S3 is connected to the detection circuit 700. The detection circuit 700 detects that the b-contact of the cutoff switch S1 is open, and outputs a signal current to the coil CR3 of the safety switch S3. When the detection circuit 700 outputs a signal current to the coil CR3 of the safety switch S3, the a-contact of the safety switch S3 closes, the bypass signal line SL2 is connected, and the relay driver 102 is able to output a signal current to the coil CR2 of the bypass switch S2. On the other hand, when the detection circuit 700 does not output a signal current to the coil CR3 of the safety switch S3, the a-contact of the safety switch S3 opens, the bypass signal line SL2 is cut off, and the relay driver 102 is unable to output a signal current to the coil CR2 of the bypass switch S2.

[0074] That is, during the period when no signal current is output from the detection circuit 700 to the coil CR3 of the safety switch S3, the bypass signal line SL2 is disconnected by the safety switch S3, and a state is maintained in which a signal current cannot be output from the relay driver 102 to the coil CR2 of the bypass switch S2. Then, during the period when a signal current is output from the detection circuit 700 to the coil CR3 of the safety switch S3, the bypass signal line SL2 is connected by the safety switch S3, and a state in which a signal current can be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained.

[0075] The following describes an example of the configuration of the detection circuit 700. Note that the detection circuit 700 only needs to detect whether the cutoff switch S1 is in a connected state or a cutoff state, and the configuration for this purpose may be modified as appropriate.

[0076] The detection circuit 700 includes operational amplifiers A1-An and comparators C1-Cn for each of the storage battery modules M1-Mn. The operational amplifiers A1-An are differential amplifier circuits. The positive input terminals (+) of the operational amplifiers A1-An are connected between the cutoff switch S1 and the positive electrodes of the storage battery modules M1-Mn. The negative input terminals (-) of the operational amplifiers A1-An are connected between the cutoff switch S1 and the load or the charge / discharge circuit 11. Furthermore, the output terminals of the operational amplifiers A1-An are connected to the positive input terminals (+) of the comparators C1-Cn.

[0077] The operational amplifiers A1 to An amplify the difference between the input voltage at the positive input terminal (+) and the input voltage at the negative input terminal (-) and output it from the output terminal to the positive input terminals (+) of the comparators C1 to Cn. That is, the operational amplifiers A1 to An detect the potential difference across the cutoff switch S1 and output it to the positive input terminals (+) of the comparators C1 to Cn.

[0078] The output terminals of the comparators C1 to Cn are connected to the coil CR3 of the safety switch S3. The comparators C1 to Cn detect the output voltage V out and the reference voltage V ref The comparators C1 to Cn compare the output voltages V out is the reference voltage V ref When the voltage becomes higher, a signal current is output from the output terminal to the coil CR3 of the safety switch S3.

[0079] 8 is a circuit diagram showing an outline of a power storage system 8 including bypass circuits B1 to Bn according to another embodiment of the present invention. The power storage system 8 of this embodiment differs from the power storage system 7 of the above embodiment in the presence or absence of a safety switch S3.

[0080] In the power storage system 8 of this embodiment, the detection circuit 700 detects that the b-contact of the cutoff switch S1 is open and outputs a signal current to the MCU 101. When the signal current is output from the detection circuit 700 to the MCU 101, the MCU 101 permits the output of the signal current from the relay driver 102 to the coil CR2 of the bypass switch S2. On the other hand, when the signal current is not output from the detection circuit 700 to the MCU 101, the MCU 101 prohibits the output of the signal current from the relay driver 102 to the coil CR2 of the bypass switch S2.

[0081] That is, during a period in which a signal current is not output from the detection circuit 700 to the MCU 101, a state in which a signal current cannot be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained. And, during a period in which a signal current is output from the detection circuit 700 to the MCU 101, a state in which a signal current can be output from the relay driver 102 to the coil CR2 of the bypass switch S2 is maintained.

[0082] The present invention has been described above based on the above-mentioned embodiment, but the present invention is not limited to the above-mentioned embodiment, and modifications may be made within the scope of the spirit of the present invention, and publicly known or well-known technologies may be combined as appropriate.

[0083] For example, in the above-described embodiment, relays are used as the cutoff switch S1, the bypass switch S2, and the safety switch S3. In a relay, a delay time exists between the energization of the coil and the opening and closing of the contacts. For example, in the energy storage system 1 (see FIG. 1) of the above-described embodiment, a delay time exists between the start of output of the cutoff signal and the closing of the a-contact of the safety switch S3. This delay time becomes the delay time between the start of output of the cutoff signal and the time when the bypass signal can be output, and the switching of the bypass line BL to the connected state is delayed with respect to the switching of the storage battery modules M1 to Mn to the cutoff state.

[0084] However, it is not essential that the cutoff switch S1, the bypass switch S2, and the safety switch S3 are relays, and they may be semiconductor switches such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). In this case, it is preferable to add a delay element such as a CR filter to the gate drive circuit so that it functions in the same way as a relay. [Explanation of symbols]

[0085] 1: Energy storage system 2: Energy storage system 3: Energy storage system 4: Energy storage system 5: Energy storage system 6: Energy storage system 7: Energy storage system 8: Energy storage system 100: Control unit 101: MCU (output control unit) 102: Relay driver (control circuit) 700: Detection circuit (detection section) a: a contact (first contact, second contact) b: b contact (first contact, second contact) B1~Bn: Bypass circuit BL: Bypass line CR1: Coil (drive part) CR2: Coil (drive part) CR3: Coil (drive part) M1~Mn: Battery module (battery) S1: Shut-off switch (first switch) S1': shutoff switch (first switch, third switch, common closing prevention means) S2: Bypass switch (second switch) S2': Bypass switch (second switch, third switch, common closing prevention means) S3: Safety switch (third switch, common closing prevention means) SL1: Shutdown signal line (first signal line) SL2: Bypass signal line (second signal line)

Claims

1. A bypass circuit provided in a power storage system including a plurality of storage batteries connected in series, for bypassing the storage batteries, a first switch provided between the adjacent storage batteries and opened and closed in response to a first control signal output from a control circuit; a bypass line that bypasses the first switch and the storage battery; a second switch provided in the bypass line and opened and closed in response to a second control signal output from the control circuit; a co-closure prevention means for preventing the first switch and the second switch from being in a co-closed state; a first signal line for transmitting the first control signal output from the control circuit to the first switch; a second signal line for transmitting the second control signal output from the control circuit to the second switch; Equipped with the co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a co-closed state, The third switch is a first contact provided on the second signal line; a driving unit that is operated by the first control signal to open and close the first contact; Equipped with The first contact is a bypass circuit that opens when the first switch is closed to interrupt the second signal line.

2. The bypass circuit according to claim 1 , wherein the third switch is provided in a control unit including the control circuit.

3. The first switch is a second contact provided on a power line connecting the adjacent storage batteries; the driving unit is operated by the first control signal to open and close the first contact and the second contact; 2. The bypass circuit according to claim 1, wherein the first contact is open to interrupt the second signal line when the second contact is closed.

4. A bypass circuit provided in a power storage system having a plurality of storage batteries connected in series, for bypassing the storage batteries, a first switch provided between the adjacent storage batteries and opened and closed in response to a first control signal output from a control circuit; a bypass line that bypasses the first switch and the storage battery; a second switch provided in the bypass line and opened and closed in response to a second control signal output from the control circuit; a co-closure prevention means for preventing the first switch and the second switch from being in a co-closed state; a first signal line for transmitting the first control signal output from the control circuit to the first switch; a second signal line for transmitting the second control signal output from the control circuit to the second switch; Equipped with the co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a co-closed state, The third switch is a first contact provided on the first signal line; a driving unit that is operated by the second control signal to open and close the first contact; Equipped with The first contact is a bypass circuit that opens when the second switch is closed to interrupt the first signal line.

5. The bypass circuit according to claim 4 , wherein the third switch is provided in a control unit including the control circuit.

6. The second switch is a second contact provided on the bypass line; the driving unit is operated by the second control signal to open and close the first contact and the second contact; The bypass circuit according to claim 4 , wherein the first contact is open when the second contact is closed to interrupt the first signal line.

7. A bypass circuit provided in a power storage system having a plurality of storage batteries connected in series, for bypassing the storage batteries, a first switch provided between the adjacent storage batteries and opened and closed in response to a first control signal output from a control circuit; a bypass line that bypasses the first switch and the storage battery; a second switch provided in the bypass line and opened and closed in response to a second control signal output from the control circuit; a co-closure prevention means for preventing the first switch and the second switch from being in a co-closed state; a first signal line for transmitting the first control signal output from the control circuit to the first switch; a second signal line for transmitting the second control signal output from the control circuit to the second switch; Equipped with the co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a co-closed state, The third switch is a first contact provided on the second signal line; A detection unit that detects an open state of the first switch; a drive unit that operates in response to a detection signal from the detection unit to open and close the first contact; Equipped with The first contact is a bypass circuit that opens to interrupt the second signal line when the detection unit does not detect that the first switch is open, and closes to connect the second signal line when the detection unit detects that the first switch is open.

8. A bypass circuit provided in a power storage system having a plurality of storage batteries connected in series, for bypassing the storage batteries, a first switch provided between the adjacent storage batteries and opened and closed in response to a first control signal output from a control circuit; a bypass line that bypasses the first switch and the storage battery; a second switch provided in the bypass line and opened and closed in response to a second control signal output from the control circuit; a co-closure prevention means for preventing the first switch and the second switch from being in a co-closed state; a first signal line for transmitting the first control signal output from the control circuit to the first switch; a second signal line for transmitting the second control signal output from the control circuit to the second switch; Equipped with The co-closing prevention means is A detection unit that detects an open state of the first switch; an output control unit that determines whether or not to output the second control signal in response to a detection signal from the detection unit; Equipped with A bypass circuit in which the second control signal is not output when the detection unit does not detect that the first switch is open, and is output when the detection unit detects that the first switch is open.

9. A plurality of storage batteries connected in series; a bypass circuit for bypassing the storage battery; A power storage system comprising: The bypass circuit includes: a first switch provided between the adjacent storage batteries and opened and closed in response to a first control signal output from a control circuit; a bypass line that bypasses the first switch and the storage battery; a second switch provided in the bypass line and opened and closed in response to a second control signal output from the control circuit; a co-closure prevention means for preventing the first switch and the second switch from being in a co-closed state; a first signal line for transmitting the first control signal output from the control circuit to the first switch; a second signal line for transmitting the second control signal output from the control circuit to the second switch; Equipped with the co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a co-closed state, The third switch is a first contact provided on the second signal line; a driving unit that is operated by the first control signal to open and close the first contact; Equipped with The first contact is open to interrupt the second signal line when the first switch is closed.

10. A storage battery system comprising: a bypass circuit for bypassing the storage battery; A power storage system comprising: The bypass circuit includes: a first switch provided between the adjacent storage batteries and opened and closed in response to a first control signal output from a control circuit; a bypass line that bypasses the first switch and the storage battery; a second switch provided in the bypass line and opened and closed in response to a second control signal output from the control circuit; a co-closure prevention means for preventing the first switch and the second switch from being in a co-closed state; a first signal line for transmitting the first control signal output from the control circuit to the first switch; a second signal line for transmitting the second control signal output from the control circuit to the second switch; Equipped with the co-closure prevention means includes a third switch that prevents the first switch and the second switch from being in a co-closed state, The third switch is a first contact provided on the first signal line; a driving unit that is operated by the second control signal to open and close the first contact; Equipped with The first contact is open to interrupt the first signal line when the second switch is closed.

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