Battery

Abstract

A battery according to the present invention, in which at least two cells are electrically connected in series to generate power through an oxidation-reduction reaction by causing an electrolytic solution to flow to at least negative electrodes, comprises: an inflow part that causes the electrolytic solution to flow into each negative electrode; an outflow part that causes the electrolytic solution to flow out; and a control unit that controls circulation of the electrolytic solution. The inflow part has inflow-side switching valves that switch respective cells between a communication state in which the electrolytic solution is circulated and a non-communication state in which the circulation of the electrolytic solution is blocked. The control unit performs opening / closing control of the inflow-side switching valves by interlocking the valves so that at least one cell is in the communication state and the other cells are in the non-communication state.

Description

battery

[0001] The present disclosure relates to a battery capable of achieving high voltage.

[0002] A known liquid exchange battery is a battery (redox flow battery) that circulates an electrolyte solution through the positive and / or negative electrodes and performs charging and discharging by utilizing the oxidation-reduction reaction of the active material contained in the electrolyte solution. In such a battery, a plurality of cells are electrically connected in series or parallel to achieve high voltage and high current. Furthermore, the battery is highly durable because the electrolyte solution can be reused repeatedly.

[0003] Patent Document 1 describes a redox flow battery in which multiple cells are electrically connected in series. In Patent Document 1, electrolyte solution flows out of an upstream cell and into a downstream cell, where it is supplied to each cell. A three-way valve is provided in the flow path through which the electrolyte solution flows into each cell, and can be operated to prevent the electrolyte solution from flowing into a specific cell.

[0004] JP 2014-505976 A

[0005] In Patent Document 1, although it is possible to operate the device so as to prevent the electrolyte from flowing into a specific cell, if the electrolyte flow path between the cells is short, a short circuit via the electrolyte is likely to occur.

[0006] Therefore, there is a demand for a battery in which a plurality of cells are electrically connected in series, but which does not cause a short circuit via the electrolyte.

[0007] A characteristic configuration of the battery according to the present disclosure is a battery in which at least two or more cells are electrically connected in series and generate electricity by an oxidation-reduction reaction by flowing an electrolyte solution through at least the negative electrode, and the battery comprises an inlet section for flowing the electrolyte solution into each of the negative electrodes, an outlet section for flowing the electrolyte solution out, and a control section for controlling the flow of the electrolyte solution, and the inlet section has an inlet-side switching valve for switching between a connected state in which the electrolyte solution is circulated and a non-connected state in which the circulation of the electrolyte solution is blocked for each of the cells, and the control section controls the opening and closing of each of the inlet-side switching valves in conjunction with each other so as to bring at least one of the cells into a connected state and the other cells into a non-connected state.

[0008] When two or more cells are electrically connected in series and an equipotential electrolyte flows into each cell, a short path for the electrolyte between the cells may result in a short circuit between adjacent cells via the electrolyte. However, with this configuration, the inlet portion has an inlet-side switching valve that switches between a connected state in which the electrolyte circulates between each cell and a disconnected state in which the electrolyte circulation is blocked. Therefore, when at least one cell is connected, the other cells can be disconnected, allowing a potential difference to be generated between the cells. This prevents a short circuit between adjacent cells via the electrolyte.

[0009] Furthermore, when the battery is discharged, the electrical energy of each cell is consumed, which reduces the state of charge (SOC) of each cell and reduces the power available to the battery as a whole. Therefore, by controlling the opening and closing of each inlet-side switching valve in conjunction with each other at regular intervals, the control unit can stagger the timing at which each cell becomes connected, allowing charged electrolyte to flow into each cell at regular intervals, raising the SOC of each cell and maintaining a constant voltage for the entire battery.

[0010] In this way, the battery is capable of preventing short circuits via the electrolyte while achieving a high voltage, and is capable of maintaining a constant voltage as a whole.

[0011] 1 is a schematic diagram of a battery according to a first embodiment; FIG. 2 is a schematic diagram of a battery according to a first embodiment; FIG. 3 is a diagram showing a transition of voltage over time; FIG. 4 is a schematic diagram of a battery according to a second embodiment; and FIG. 5 is a schematic diagram of an inlet-side switching valve according to a second embodiment.

[0012] Hereinafter, embodiments of the battery according to the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0013] First Embodiment A battery 10 (redox flow battery) according to a first embodiment will be described with reference to Fig. 1 . Fig. 1 is a diagram showing a schematic configuration of the battery 10. The battery 10 includes at least two or more cells 1 (three in this embodiment), an inlet portion 2 through which an electrolyte solution, which is an anode fluid, flows into an anode 12, an outlet portion 3 through which the electrolyte solution flows out from the anode 12, and an electrolyte tank 4. The battery 10 is connected to a power source 6 or a load 7 via a power converter 5, and is charged by receiving power from the power source 6 during charging, and supplies power to the load 7 during discharging.

[0014] Each cell 1 has a positive electrode 11 that houses a positive electrode and is supplied with a positive electrode fluid containing a positive electrode active material, a negative electrode 12 that houses a negative electrode and is supplied with an electrolyte containing a negative electrode active material, and an ion exchange membrane 13 that separates the positive electrode 11 and the negative electrode 12. In the positive electrode 11, an oxidation reaction occurs during charging, in which the reduced positive electrode active material changes to an oxidized state, and a reduction reaction occurs during discharging, in which the oxidized positive electrode active material changes to a reduced state. Meanwhile, in the negative electrode 12, a reduction reaction occurs during charging, in which the oxidized negative electrode active material changes to a reduced state, and an oxidation reaction occurs during discharging, in which the reduced negative electrode active material changes to an oxidized state. The battery 10 is charged and discharged using the oxidation-reduction reactions of the positive electrode active material and the negative electrode active material.

[0015] The ion exchange membrane 13 is an ion exchange membrane that does not transmit electrons but transmits, for example, hydrogen ions, and maintains the electrical neutrality of the positive electrode fluid and the negative electrode fluid by transmitting protons or hydroxide ions generated at the positive electrode 11 or the negative electrode 12.

[0016] 1, the plurality of cells 1 are electrically connected in series by conductors 50. Hereinafter, when it is necessary to distinguish between the three cells 1, they will be described as cells 1A, 1B, and 1C.

[0017] For the positive electrode fluid and the negative electrode fluid, known electrolytes containing active materials such as Fe / Cr-based or vanadium-based can be used, but the electrolyte used as the negative electrode fluid is preferably one in which a hydrogen storage alloy, zinc, or the like, which is a negative electrode active material, is dispersed. In an electrolyte in which a hydrogen storage alloy, zinc, or the like is dispersed, the resistance of the electrolyte itself can be reduced, thereby making it possible to increase the electrical conductivity. The alloy composition of the hydrogen storage alloy is not limited as long as it is capable of absorbing hydrogen gas. When the active material contains Fe / Cr-based or vanadium-based materials, the solvent for the electrolyte is preferably an acidic aqueous solution, for example, sulfuric acid (H ２ SO ４ ) aqueous solution, and phosphoric acid (H ３ P.O. ４ ) aqueous solution, etc. can be used. When a hydrogen storage alloy or a metal such as zinc is dispersed in the active material, an alkaline aqueous solution is preferable, and for example, a sodium hydroxide (NaOH) aqueous solution, a potassium hydroxide (KOH) aqueous solution, etc. can be used. Furthermore, air or oxygen can be used as the positive electrode fluid, and the positive electrode 11 can be an air electrode. Hereinafter, the positive electrode fluid will be referred to as air, and the negative electrode fluid will be referred to as electrolyte.

[0018] The inlet section 2, which allows the electrolyte to flow into the negative electrode 12, has a flow path 20 connected to the electrolyte tank 4 and through which the electrolyte flows, and a pump 25 provided on the flow path 20 and which delivers the electrolyte. The flow path 20 is connected to flow paths 21 and 22 via an inlet-side switching valve 26. The flow path 21 is connected to the negative electrode 12 of cell 1C. The flow path 22 is also connected to flow paths 23 and 24 via an inlet-side switching valve 27. The flow path 23 is connected to the negative electrode 12 of cell 1B, and the flow path 24 is connected to the negative electrode 12 of cell 1A. In other words, the electrolyte is supplied to each cell 1 in parallel. The inlet-side switching valves 26 and 27 can be two-way or three-way valves.

[0019] Furthermore, the outlet 3, which discharges the electrolyte from the negative electrode 12, has a flow path 30 connected to the electrolyte tank 4 and through which the electrolyte flows. The flow path 30 is connected to flow paths 31 and 32 via an outlet-side switching valve 36, and the flow path 32 is connected to flow paths 33 and 34 via an outlet-side switching valve 37. The outlet-side switching valves 36 and 37 are, for example, two-way valves or three-way valves. The flow paths 31, 33, and 34 are connected to the negative electrode 12 of cell 1C, the negative electrode 12 of cell 1B, and the negative electrode 12 of cell 1A, respectively, and the electrolyte flows out of each cell 1 in parallel and into the electrolyte tank 4.

[0020] When the battery 10 is charged and discharged, the reduced or oxidized negative electrode active material flows into the electrolyte tank 4 from the outlet 3, resulting in a mixture of the reduced and oxidized negative electrode active materials in the electrolyte tank 4. Therefore, the electrolyte tank 4 may have a separator (not shown) that prevents the mixture of the reduced and oxidized negative electrode active materials. The separator can prevent the mixture of the reduced and oxidized negative electrode active materials, thereby making it possible to maintain a constant concentration of the electrolyte.

[0021] The flow paths provided in the inlet portion 2 and the outlet portion 3 may be formed integrally with the housing that houses the cell 1. The battery 10 also has an inlet portion (not shown) through which air flows in and an outlet portion (not shown) through which air flows out of the positive electrode 11. The inlet portion of the positive electrode 11 may also have an air pump that sends out air.

[0022] The inlet section 2 and the outlet section 3 circulate the electrolyte and air through each cell 1, causing an oxidation-reduction reaction in each cell 1. Here, when the inlet-side switching valve 26 connects the flow path 20 to the flow path 21 and the inlet-side switching valve 27 connects the flow path 22 to the flow path 23 and the flow path 24, the electrolyte simultaneously flows into all of the cells 1A, 1B, and 1C. Since the potential of the electrolyte flowing into each cell 1 is equal, if the electrolyte flow paths between the serially connected cells 1A and 1B and between the serially connected cells 1B and 1C are short, a short circuit through the electrolyte is likely to occur between the cells. In particular, when an electrolyte containing a dispersed hydrogen storage alloy or zinc is used as the electrolyte, the resistance of the electrolyte itself is low and therefore the electrolyte itself is electrically conductive, making a short circuit through the electrolyte a likely problem. Therefore, in this embodiment, the battery 10 has a control unit 8 that controls the opening and closing of the inlet side switching valves 26, 27 and the outlet side switching valves 36, 37 in conjunction with each other to prevent a short circuit through the electrolyte, and switches between a connected state in which the electrolyte is circulated to each cell 1 and a disconnected state in which the circulation of the electrolyte is blocked.

[0023] In a communication state in which the electrolyte circulates only through cell 1A, the control unit 8 switches the inlet-side switching valves 26 and 27 to connect flow path 20 to flow path 22 and to connect flow path 22 to flow path 24 (see FIG. 2 ). At this time, the control unit 8 preferably switches the outlet-side switching valves 36 and 37 in conjunction with the inlet-side switching valves 26 and 27. When the control unit 8 switches the outlet-side switching valves 36 and 37 to connect flow path 34 to flow path 32 and flow path 32 to flow path 30, the electrolyte circulates through the electrolyte tank 4, flow paths 20, 22, and 24, cell 1A, and flow paths 34, 32, and 30. In other words, cell 1A is in a communication state in which the electrolyte circulates, while cells 1B and 1C are in a non-communication state in which the electrolyte does not circulate. Therefore, the cells 1 are not connected via the electrolyte, and no short circuit occurs between the cells 1. It is preferable that the control unit 8 operates the pump 25 when bringing each cell 1 into communication.

[0024] Similarly, in a communication state in which the electrolyte circulates only through cell 1B, the control unit 8 switches the inlet-side switching valves 26 and 27 to connect flow path 20 to flow path 22 and to connect flow path 22 to flow path 23. Then, in synchronization with the inlet-side switching valves 26 and 27, the control unit 8 switches the outlet-side switching valves 36 and 37 to connect flow path 33 to flow path 32 and to connect flow path 32 to flow path 30. As a result, the electrolyte circulates through the electrolyte tank 4, flow paths 20, 22, and 23, cell 1B, and flow paths 33, 32, and 30, and the electrolyte circulates through cell 1B. In a communication state in which the electrolyte circulates only through cell 1C, the control unit 8 switches the inlet-side switching valves 26 and 27 and the outlet-side switching valves 36 and 37 in synchronization, so that the electrolyte circulates through the electrolyte tank 4, flow paths 20 and 21, cell 1C, and flow paths 31 and 30 (see FIG. 1 ). Note that, instead of the outlet-side switching valves 36 and 37, check valves may be provided in the respective flow paths 31, 33, and 34 of the outlet portion 3. Even in this case, the inlet-side switching valves 26 and 27 are switched in conjunction with each other, so that only one cell 1 is in a connected state, and therefore, no short circuit occurs via the electrolyte flowing through each flow path of the outlet portion 3.

[0025] Furthermore, in the electrolyte communication state, the electrolyte in which the amount of reduced negative electrode active material in each cell 1 increases or decreases as the battery 10 is charged or discharged flows into the electrolyte tank 4, and the electrolyte in which the amount of negative electrode active material in the electrolyte tank 4 decreases or increases flows into each cell 1. Therefore, by circulating the electrolyte through the cells 1 in a communication state, it is possible to supply the negative electrode active material in an oxidized state or a reduced state to each cell 1. Note that the circulation of air at the positive electrode 11 of each cell 1 may be performed in conjunction with the circulation of air at the negative electrode 12, or may be performed so as to make the states of charge of the negative electrode active material and the positive electrode active material equivalent.

[0026] Next, the circulation operation of the electrolyte will be described using FIGS. 1 to 3 . In the initial state, flow path 20 is not connected to flow path 22, and flow path 22 is not connected to flow path 24. That is, each cell 1 is not connected to the other cells 1 through their respective flow paths, and each cell 1 is in a non-communicating state in which the circulation of the electrolyte is interrupted. In the initial state, the battery 10 is fully charged by power supplied from the power source 6, and the positive electrode active material in each cell 1 is in an oxidized state, and the negative electrode active material is in a reduced state. Note that the negative electrode active material in the electrolyte tank 4 is also all in a reduced state, and the positive electrode active material in the positive electrode fluid tank, which stores air as the positive electrode fluid, is also all in an oxidized state. The voltage of the entire battery 10 at this time is the sum of the voltages V [V] of each cell 1, so the voltage of the entire battery 10 in this embodiment is 3 V [V]. When the battery 10 supplies power to the load 7 and discharges, the amount of positive electrode active material in the positive electrode 11 of each cell 1 that is reduced increases, and the amount of negative electrode active material in the negative electrode 12 that is oxidized increases. This causes the state of charge (SOC) of each cell 1 to decrease, and as shown in Figure 3, the voltage of each cell 1 at time t1, Δt seconds after the battery 10 starts discharging, drops by ΔV / 3 [V] from V [V]. Note that the SOC indicates the remaining amount of charge, and is, for example, the ratio of the current amount of charge to the amount of charge in a fully charged state, expressed on a scale of 0 to 100%.

[0027] As shown in FIG. 2 , at time t1, Δt seconds after the start of discharge of battery 10, control unit 8 switches inlet-side switching valves 26 and 27 to connect flow path 20 to flow path 22 and to connect flow path 22 to flow path 24 so that cell 1A is in a communication state for circulating the electrolyte. Also, control unit 8 switches outlet-side switching valves 37 and 36 to connect flow path 34 to flow path 32 and to connect flow path 32 to flow path 30, and operates pump 25. As a result, the reduced negative electrode active material flows from electrolyte tank 4 into cell 1A, increasing the SOC of cell 1A. As shown in FIG. 3 , the voltage of cell 1A recovers from V−ΔV / 3 [V] to V [V]. At this time, the voltages of cells 1B and 1C are V−ΔV / 3 [V], so the overall voltage of battery 10 becomes 3V−2ΔV / 3 [V].

[0028] Next, at time t2, Δt seconds after cell 1A enters the connected state, control unit 8 switches inlet-side switching valves 26, 27 and outlet-side switching valves 36, 37 so that cell 1A enters a non-connected state in which electrolyte does not circulate, and cell 1B enters a connected state in which electrolyte circulates. As at time t1, reduced negative electrode active material flows from electrolyte tank 4 into cell 1B, increasing the SOC of cell 1B and restoring the voltage of cell 1B from V-2ΔV / 3 [V] to V [V]. At this time, the voltage of cell 1A is V-ΔV / 3 [V] and the voltage of cell 1C is V-2Δ / 3 [V], so the voltage of the entire battery 10 becomes 3V-ΔV [V].

[0029] At time t3, Δt seconds after cell 1B enters the connected state, the control unit 8 switches the inlet-side switching valves 26, 27 and the outlet-side switching valves 36, 37 so that cell 1B enters a non-connected state in which electrolyte does not circulate and cell 1C enters a connected state in which electrolyte circulates (see FIG. 1). At time t3, as at time t1, the reduced negative electrode active material flows into cell 1C, causing the voltage of cell 1C to recover from V-ΔV [V] to V [V]. At this time, the voltage of cell 1A is V-2ΔV / 3 [V] and the voltage of cell 1C is V-Δ / 3 [V], so the overall voltage of the battery 10 is 3V-ΔV [V]. The control unit 8 repeatedly switches the lowest-voltage cell 1 of each cell 1 into the connected state every Δt seconds. This allows the overall voltage of the battery 10 to be maintained constant. The timing for switching each cell 1 to the communication state may be determined according to the number of cells 1 in the battery 10. For example, if n cells 1 are connected, each cell 1 can be switched between the communication state and the non-communication state every time the voltage of the cell 1 drops by V / n [V].

[0030] As the discharge of the battery 10 progresses, much of the negative electrode active material circulating through the battery 10 becomes oxidized, and much of the positive electrode active material becomes reduced. When the operation of the load 7 stops or the SOC of the battery 10 decreases, the battery 10 stops discharging and generates power using the power supplied from the power source 6. The battery 10 generates power by behaving in a manner opposite to the behavior during charging described above. That is, the control unit 8 switches the inlet-side switching valves 26, 27 and the outlet-side switching valves 36, 37 to establish a communication state in which the electrolyte circulates through one of the cells 1. In the communication state, the oxidized negative electrode active material flows from the electrolyte tank 4 into the cell 1, a power generation reaction progresses in the cell 1, and the reduced negative electrode active material in the cell 1 flows into the electrolyte tank 4. Therefore, by switching between the connected and disconnected states of each cell 1, the control unit 8 returns the reduced negative electrode active material to the electrolyte tank 4, thereby efficiently generating power without causing a short circuit via the electrolyte between adjacent cells 1. The timing of switching between the connected and disconnected states of each cell 1 during power generation may be different from that during discharge.

[0031] Second Embodiment FIG. 4 is a schematic diagram of a battery 10 according to a second embodiment. In the second embodiment, one inlet-side switching valve 26 and one outlet-side switching valve 36 are provided. The inlet-side switching valve 26 in this embodiment is a rotary valve as shown in FIG. 5 , and is switched by the control unit 8. That is, by rotating the inlet-side switching valve 26, the control unit 8 connects one of the multiple outlets 26A (three in this embodiment) from which the electrolyte flows to one of the flow paths of the inlet section 2, thereby placing each cell 1 in a connected state in which the electrolyte circulates. Therefore, the connected and disconnected states of each cell 1 are switched in unison along a single axis. When the outlet 26A is not connected to any of the flow paths, the electrolyte does not circulate through each cell 1, and the pump 25 does not operate. The configuration of the outlet-side switching valve 36 can be similar to that of the inlet-side switching valve 26. Note that only one outlet 26A may be provided. Furthermore, any type of valve that allows the electrolyte to flow in only one direction may be used for the inlet-side switching valve 26 and the outlet-side switching valve 36. The other configurations are the same as those of the first embodiment, and therefore detailed description of the same configurations will be omitted.

[0032] In this embodiment, one inlet-side switching valve 26 switches the connection between flow path 20 and another flow path, and one outlet-side switching valve 36 switches the connection between flow path 30 and another flow path, so there is no need to use multiple switching valves in the inlet section 2 and the outlet section 3. This makes it possible to reduce the number of parts in the battery 10 and make the battery 10 more compact. Furthermore, because the control unit 8 does not need to control multiple switching valves in conjunction with each other, the configuration of the control unit 8 is simplified, making it possible to reduce the manufacturing cost of the battery 10.

[0033] The above-described embodiment may include the following configuration: (1) A battery 10 in which at least two or more cells 1 are electrically connected in series and generate electricity by an oxidation-reduction reaction when an electrolyte solution flows through at least the negative electrodes 12, the battery 10 including an inlet section 2 for inflowing the electrolyte solution into each negative electrode 12, an outlet section 3 for outflowing the electrolyte solution, and a control section 8 for controlling the flow of the electrolyte solution, the inlet section 2 having inlet-side switching valves 26, 27 for switching between a communication state in which the electrolyte solution circulates and a non-communication state in which the circulation of the electrolyte solution is blocked, and the control section 8 for controlling the opening and closing of the inlet-side switching valves 26, 27 in conjunction with each other so as to bring at least one cell 1 into the communication state and the other cells 1 into the non-communication state.

[0034] When two or more cells 1 are electrically connected in series and an electrolyte having the same potential flows into each cell 1, if the flow path of the electrolyte between the cells is short, there is a risk of a short circuit via the electrolyte between adjacent cells 1. However, according to this configuration, the inlet portion 2 has inlet-side switching valves 26, 27 that switch between a communication state in which the electrolyte circulates with each cell 1 and a non-communication state in which the circulation of the electrolyte is blocked. Therefore, when at least one cell 1 is in a communication state, the other cells 1 can be in a non-communication state, and a potential difference can be generated between the cells 1. This makes it possible to prevent a short circuit via the electrolyte between adjacent cells 1.

[0035] Furthermore, when discharging occurs in a battery 10 in which two or more cells 1 are electrically connected in series, the electrical energy of the cells 1 is consumed, which reduces the state of charge (SOC) of each cell 1 and reduces the power available for the entire battery 10. Therefore, by controlling the opening and closing of the inlet-side switching valves 26, 27 in conjunction with each other at regular intervals, the control unit 8 can stagger the timing at which each cell 1 becomes connected, thereby allowing charged electrolyte to flow into each cell 1 at regular intervals to increase the SOC of each cell 1 and maintaining a constant voltage for the entire battery 10.

[0036] (2) In the battery 10 of (1), it is preferable that the control unit 8 controls the opening and closing of the inlet side switching valves 26, 27 in conjunction with each other so that only one cell 1 is in a connected state and the other cells 1 are in a non-connected state.

[0037] The control unit 8 controls the opening and closing of the inlet side switching valves 26, 27 to keep only one cell 1 in a connected state and the other cells 1 in a non-connected state, thereby making it possible to reliably suppress short circuits between cells via the electrolyte.

[0038] (3) In the battery 10 of (1) or (2), it is preferable that the inlet-side switching valves 26, 27 are linked together on a single axis.

[0039] If the inlet-side switching valves 26, 27 are linked on a single axis, there is no need to provide multiple inlet-side switching valves 26, 27, which simplifies the configuration of the battery 10 and reduces the number of parts, thereby enabling the battery 10 to be made smaller.

[0040] (4) In the battery 10 of (3), the inlet section 2 has a plurality of flow paths 21, 23, 24 connecting the inlet side switching valves 26, 27 to each cell 1, and the inlet side switching valves 26, 27 have an outlet 26A that can be connected to the plurality of flow paths 21, 23, 24 as they rotate around an axis, and it is preferable that the control unit 8 rotates the inlet side switching valves 26, 27 to switch between a connected state and a disconnected state.

[0041] If the inlet-side switching valves 26, 27 have outlets 26A that can be connected to the flow paths 21, 23, or 24 as they rotate, the connection between the outlets 26A and the flow paths 21, 23, and 24 can be switched by rotating the inlet-side switching valves 26, 27, thereby simplifying the operation of switching between the connected and disconnected states of the cell 1. Furthermore, since there is no need to provide inlet-side switching valves 26, 27 for each of the flow paths 21, 23, and 24, the configuration of the battery 10 can be made compact.

[0042] (5) In the battery 10 of any one of (1) to (4), the control unit 8 preferably brings the cell 1 with the lowest voltage into communication at predetermined time intervals.

[0043] The control unit 8 controls the opening and closing of each of the inlet side switching valves 26, 27 in conjunction with each other at predetermined time intervals, thereby staggering the timing at which each cell 1 becomes connected. This makes it possible to increase the SOC of each cell 1 by flowing charged electrolyte into each cell 1 at predetermined time intervals, and maintain a constant voltage for the entire battery 10.

[0044] (6) In any of the batteries 10 of (1) to (5), the outflow section 3 has outflow side switching valves 36, 37 that switch between a connected state and a disconnected state in synchronization with the inflow side switching valves 26, 27, and it is preferable that the control unit 8 controls the opening and closing of each of the inflow side switching valves 26, 27 in conjunction with each of the outflow side switching valves 36, 37.

[0045] The outlet portion 3 has the outlet-side switching valves 36, 37 that switch between a connected state and a disconnected state in synchronization with the inlet-side switching valves 26, 27, so that it is possible to prevent a short circuit via the electrolyte also in the outlet portion 3. Furthermore, by synchronizing with the inlet-side switching valves 26, 27, it is possible to prevent damage to the ion exchange membrane 13 caused by a local increase in internal pressure within the cell 1 due to a mismatch in opening and closing timing between the inlet-side switching valves 26, 27 and the outlet-side switching valves 36, 37.

[0046] (7) In any of the batteries 10 of (1) to (6), the positive electrode 11 is preferably an air electrode.

[0047] By using the positive electrode 11 as an air electrode, it is possible to prevent mixing of the electrolyte solution within the cell 1. Furthermore, it is possible to reduce the weight of the battery 10 and to manufacture it at low cost.

[0048] Other Embodiments (a) In the above embodiment, the positive electrode fluid is air, but the positive electrode fluid may be an electrolyte solution, and the positive electrode 11 may also be provided with an inlet portion through which the electrolyte solution flows and an outlet portion through which the electrolyte solution flows, similar to the negative electrode 12. The control unit 8 may switch the positive electrode fluid, in addition to the negative electrode fluid, between a communication state and a non-communication state.

[0049] (b) In the above embodiment, flow path 22 is connected to flow path 20 via inlet-side selector valve 26, and flow path 24 is connected to flow path 22 via inlet-side selector valve 27. However, flow path 22 and flow path 24 may each be connected to the electrolyte tank 4. In this case, flow path 20 is connected only to flow path 21 via inlet-side selector valve 26, and flow path 22 is connected only to flow path 23 via inlet-side selector valve 27, and flow path 24 may be provided with a separate inlet-side selector valve. By controlling the opening and closing of these inlet-side selector valves in conjunction with each other, the control unit 8 can prevent short circuits via the electrolyte in each cell 1. The same configuration may be used for the outlet unit 3.

[0050] (c) In the above embodiment, the electrolyte tank 4 has a separator that separates the reduced-state negative electrode active material from the oxidized-state negative electrode active material. However, the battery 10 may have a tank that stores the reduced-state negative electrode active material and the oxidized-state negative electrode active material separately.

[0051] (d) In the above embodiment, the control unit 8 controls the inlet-side switching valves 26, 27 in a coordinated manner, but these do not have to be coordinated. In this case, the control unit 8 controls the outlet-side switching valves 36, 37 to open and close in synchronization with the inlet-side switching valves 26, 27. This adjusts the flow rate of the electrolyte flowing through the cell 1, making it possible to prevent damage to the ion exchange membrane 13 due to a local increase in the internal pressure of the cell 1.

[0052] (e) In the above embodiment, when cell 1A is in a communicating state, either cell 1B or cell 1C may be in a communicating state. This is because, if the flow paths 23, 24 between cell 1A and cell 1B and the flow paths 21, 22, 24 between cell 1A and cell 1C are long, a short circuit via the electrolyte will not occur even if cell 1A is in a communicating state with cell 1B or cell 1C.

[0053] The present disclosure is applicable to batteries capable of producing high voltages.

[0054] 1: cell, 2: inlet portion, 3: outlet portion, 8: control portion, 10: battery, 11: positive electrode, 12: negative electrode, 26: inlet side switching valve, 27: inlet side switching valve, 36: outlet side switching valve, 37: outlet side switching valve

Claims

1. A battery in which at least two or more cells are electrically connected in series and generate electricity by an oxidation-reduction reaction by flowing an electrolyte solution through at least the negative electrode, the battery comprising: an inlet section for flowing the electrolyte solution into each of the negative electrodes, an outlet section for flowing the electrolyte solution out, and a control section for controlling the flow of the electrolyte solution, the inlet section having an inlet side switching valve for switching between a connected state in which the electrolyte solution is circulated and a non-connected state in which the circulation of the electrolyte solution is blocked for each of the cells, and the control section controls the opening and closing of each of the inlet side switching valves in conjunction with each other to bring at least one of the cells into the connected state and the other cells into the non-connected state.

2. A battery as described in claim 1, wherein the control unit controls the opening and closing of each of the inlet side switching valves in conjunction with each other so as to place only one of the cells in the connected state and the other cells in the non-connected state.

3. The battery according to claim 1, wherein each of said inlet side switching valves is linked to one another on a single axis.

4. A battery as described in claim 3, wherein the inlet section has a plurality of flow paths connecting the inlet side switching valve and each of the cells, the inlet side switching valve has an outlet that can be connected to the plurality of flow paths as the inlet side switching valve rotates about an axis, and the control unit rotates the inlet side switching valve to switch between the connected state and the non-connected state.

5. The battery according to claim 1, wherein the control unit brings the cell with the lowest voltage into the connected state at predetermined time intervals.

6. A battery as described in claim 1, wherein the outflow section has an outflow side switching valve which switches between the connected state and the non-connected state in synchronization with the inflow side switching valve, and the control section controls the opening and closing of each of the inflow side switching valves in conjunction with each of the outflow side switching valves.

7. The battery according to any one of claims 1 to 6, wherein the positive electrode is an air electrode.

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