WO2016117265A1

WO2016117265A1 - Redox-flow battery operation method and redox-flow battery

Info

Publication number: WO2016117265A1
Application number: PCT/JP2015/085612
Authority: WO
Inventors: 克也山西; 康充筒井; 貴浩隈元; 敬二矢野
Original assignee: 住友電気工業株式会社
Priority date: 2015-01-23
Filing date: 2015-12-21
Publication date: 2016-07-28
Also published as: TW201631831A; JP2018037135A

Abstract

According to the present invention, when a positive-electrode electrolyte solution and a negative-electrode electrolyte solution are circulated in a cell stack, the circulated amount of one of the electrolyte solutions is made to be larger than the circulated amount of the other electrolyte solution such that there is a pressure differential wherein the pressure that acts from the one electrolyte solution on separator membranes of battery cells that are provided to the cell stack is greater than the pressure that acts on the separator membranes from the other electrolyte solution. In addition, the circulated amount of the one electrolyte solution is made to be larger than the circulated amount of the other electrolyte solution and the pressure differential is maintained even when the circulated amounts of the positive-electrode electrolyte solution and the negative-electrode electrolyte solution are reduced and the circulation of both electrolyte solutions is stopped.

Description

Redox flow battery operation method and redox flow battery

The present invention relates to a method for operating a redox flow battery used for instantaneous voltage drop countermeasures, power failure countermeasures, load leveling, and the like, and a redox flow battery.

One of the large-capacity storage batteries that store new energy such as solar power generation and wind power generation is an electrolyte circulation type battery, typically a redox flow battery (RF battery). An RF battery is a battery that charges and discharges using a difference in redox potential between ions contained in a positive electrode electrolyte and ions contained in a negative electrode electrolyte (see, for example, Patent Document 1). As shown in the operational principle diagram of the RF battery α in FIG. 14, the RF battery α includes a battery cell 100 separated into a positive electrode portion 102 and a negative electrode portion 103 by a diaphragm 101 that allows hydrogen ions to pass therethrough. A positive electrode 104 is built in the positive electrode part 102, and a positive electrode tank 106 for storing a positive electrode electrolyte is connected to the positive electrode forward pipe 108 and the positive electrode return pipe 110. The positive electrode forward pipe 108 is provided with a pump (positive electrode liquid feeding device) 112, and a positive electrode circulation mechanism 100 P that circulates the positive electrode electrolyte is constituted by these

members

106, 108, 110, and 112. Similarly, the negative electrode unit 103 includes a negative electrode 105 therein, and a negative electrode tank 107 that stores a negative electrode electrolyte is connected to the negative electrode forward tube 109 and the negative electrode return tube 111. The negative electrode forward pipe 109 is provided with a pump (negative electrode liquid feeding device) 113, and these

members

107, 109, 111, 113 constitute a negative electrode circulation mechanism 100 N that circulates the negative electrode electrolyte. . The electrolyte stored in the

tanks

106 and 107 is circulated in the

cells

102 and 103 by the

pumps

112 and 113 during charging and discharging. When charging / discharging is not performed, the

pumps

112 and 113 are stopped and the electrolytic solution is not circulated.

A plurality of the battery cells 100 are usually stacked inside a structure called a cell stack 200 as shown in FIG. The cell stack 200 is configured by sandwiching a laminated structure called a sub-stack 200 s from both sides with two

end plates

210 and 220 and tightening with a tightening mechanism 230 (in the illustrated configuration, a plurality of sub-stacks are arranged). 200 s is used). As shown in the upper diagram of FIG. 15, the sub-stack 200s is formed by stacking a plurality of cell units including the cell frame 120, the positive electrode 104, the diaphragm 101, the negative electrode 105, and the cell frame 120, and supplying the stacked body. It has a configuration sandwiched between the discharge plates 190 and 190 (see the lower diagram of FIG. 15). The cell frame 120 provided in the cell unit includes a frame 122 having a through window and a bipolar plate 121 that closes the through window, and is arranged so that the positive electrode 104 is in contact with one surface side of the bipolar plate 121. The negative electrode 105 is disposed on the other surface side of the bipolar plate 121 so as to be in contact therewith. In this configuration, one battery cell 100 is formed between the bipolar plates 121 of the adjacent cell frames 120.

Distribution of the electrolyte solution to the battery cell 100 via the supply /

discharge plates

190, 190 in the sub stack 200 s is performed by the

supply manifolds

123, 124 formed in the frame body 122 and the

discharge manifolds

125, 126. . The positive electrode electrolyte is supplied from the liquid supply manifold 123 to the positive electrode 104 through an inlet slit formed on one side (the front side of the paper) of the frame 122, and the outlet slit formed at the top of the frame 122 Then, the liquid is discharged to the drainage manifold 125. Similarly, the negative electrode electrolyte is supplied from the liquid supply manifold 124 to the negative electrode 105 through an inlet slit (shown by a dotted line) formed on the other surface side (back side of the paper surface) of the frame body 122. Is discharged to the drainage manifold 126 through an outlet slit (shown by a dotted line) formed in the upper portion of the liquid. An annular sealing member 127 such as an O-ring or a flat packing is disposed between the cell frames 120, and leakage of the electrolyte from the sub stack 200s is suppressed.

The input / output of electric power between the battery cell 100 provided in the sub stack 200s and the external device is performed by a current collecting structure using a current collecting plate made of a conductive material. A pair of current collecting plates is provided for each sub-stack 200s, and each current collecting plate is electrically connected to the bipolar plate 121 of the cell frame 120 positioned at both ends in the stacking direction among the stacked cell frames 120. Has been.

JP 2013-80613 A

In operation of the redox flow battery, there is a need to make either one of the pressure of the positive electrode electrolyte and the pressure of the negative electrode electrolyte acting on the diaphragm in the cell stack higher than the other. Furthermore, according to the study by the present inventors, it was found that it is preferable that the pressure of one electrolyte is maintained higher than the pressure of the other electrolyte even when the circulation of both electrolytes is stopped. It was. Note that which pressure is to be increased is case by case.

The present invention has been made in view of the above circumstances, and one of its purposes is the pressure of the positive electrode electrolyte acting on the diaphragm in the cell stack from the circulation to the stop of the positive electrode electrolyte and the negative electrode electrolyte. Another object of the present invention is to provide a redox flow battery operating method and a redox flow battery in which one of the pressure of the negative electrode electrolyte and the pressure of the negative electrode electrolyte can be made higher than the other.

A method for operating a redox flow battery according to an aspect of the present invention is to circulate a positive electrode electrolyte using a positive electrode circulation mechanism in a cell stack in which a plurality of battery cells having a positive electrode, a negative electrode, and a diaphragm are stacked, This is a method for operating a redox flow battery in which a negative electrode electrolyte is circulated using a negative electrode circulation mechanism. In the operating method of the redox flow battery, when the positive electrode electrolyte and the negative electrode electrolyte are circulated through the cell stack, the circulation amount of one electrolyte is larger than the circulation amount of the other electrolyte, The pressure of the one electrolytic solution acting on the diaphragm is set to a differential pressure state higher than the pressure of the other electrolytic solution acting on the diaphragm, and the circulation amount of the positive electrode electrolyte and the negative electrode electrolyte is decreased. Even when the circulation of the electrolytic solution is stopped, the circulating amount of the one electrolytic solution is made larger than the circulating amount of the other electrolytic solution to maintain the differential pressure state.

A redox flow battery according to an embodiment of the present invention includes a cell stack in which a plurality of battery cells having a positive electrode, a negative electrode, and a diaphragm are stacked, and a positive electrode circulation mechanism that circulates a positive electrode electrolyte in the cell stack; A redox flow battery comprising a negative electrode circulation mechanism for circulating a negative electrode electrolyte in the cell stack. The redox flow battery includes the positive electrode circulation mechanism so that the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution from the circulation to the stop of the cathode electrolyte and the anode electrolyte. A flow rate controller for controlling the negative electrode circulation mechanism is provided.

According to the above redox flow battery operation method and redox flow battery, the pressure of the positive electrode electrolyte and the pressure of the negative electrode electrolyte acting on the diaphragm in the cell stack during the circulation and stop of the positive electrode electrolyte and the negative electrode electrolyte. Any one of the above can be made higher than the other.

It is a schematic block diagram of the redox flow battery which concerns on embodiment. It is a graph which concerns on the control pattern I which stops the circulation of a positive electrode electrolyte and a negative electrode electrolyte. It is a graph which concerns on the control pattern II which stops the circulation of a positive electrode electrolyte and a negative electrode electrolyte. It is a schematic block diagram of the differential pressure formation mechanism comprised by making the return pipe for positive electrodes longer than the return pipe for negative electrodes. It is a schematic block diagram of the differential pressure formation mechanism comprised by making the return pipe for positive electrodes thinner than the return pipe for negative electrodes. It is a schematic block diagram of the differential pressure formation mechanism comprised by bending the return pipe for positive electrodes more complicatedly than the return pipe for negative electrodes. It is a schematic block diagram of the differential pressure | voltage formation mechanism comprised with the heat exchanger for positive electrodes, and the heat exchanger for negative electrodes. It is a graph which concerns on the control pattern III which stops the circulation of a positive electrode electrolyte and a negative electrode electrolyte. It is a graph which concerns on the control pattern IV which stops the circulation of a positive electrode electrolyte and a negative electrode electrolyte. It is a schematic block diagram of the differential pressure formation mechanism comprised by making the return pipe for negative electrodes longer than the return pipe for positive electrodes. It is a schematic block diagram of the differential pressure formation mechanism comprised by making the return pipe for negative electrodes thinner than the return pipe for positive electrodes. It is a schematic block diagram of the differential pressure formation mechanism comprised by bending the return pipe for negative electrodes more complicatedly than the return pipe for positive electrodes. It is a schematic block diagram of the differential pressure | voltage formation mechanism comprised with the heat exchanger for positive electrodes, and the heat exchanger for negative electrodes. It is an operation | movement principle figure of a redox flow battery. It is a schematic block diagram of a cell stack.

[Description of Embodiment of the Present Invention]
First, the contents of the embodiment of the present invention will be listed and described.

<1> The operation method of the redox flow battery according to the embodiment circulates the positive electrode electrolyte using a positive electrode circulation mechanism in a cell stack in which a plurality of battery cells each having a positive electrode, a negative electrode, and a diaphragm are stacked. This is a method for operating a redox flow battery in which a negative electrode electrolyte is circulated using a negative electrode circulation mechanism. In the operating method of the redox flow battery, when the positive electrode electrolyte and the negative electrode electrolyte are circulated through the cell stack, the circulation amount of one electrolyte is larger than the circulation amount of the other electrolyte, The pressure of the one electrolytic solution acting on the diaphragm is set to a differential pressure state higher than the pressure of the other electrolytic solution acting on the diaphragm, and the circulation amount of the positive electrode electrolyte and the negative electrode electrolyte is decreased. Even when the circulation of the electrolytic solution is stopped, the circulating amount of the one electrolytic solution is made larger than the circulating amount of the other electrolytic solution to maintain the differential pressure state.

When either one of the pressure of the positive electrode electrolyte in the cell stack or the pressure of the negative electrode electrolyte is made higher than the other, the pressure of the one electrolyte acting on the diaphragm in the cell stack becomes the other electrolyte acting on the diaphragm. It becomes a differential pressure state higher than the pressure. According to the study by the present inventors, when the above-mentioned differential pressure state is maintained when both electrolytic solutions are circulated, the above-mentioned differential pressure state can be maintained even when the circulation of both electrolytic solutions is stopped. The knowledge that it was preferable was obtained. This is because if the direction of the pressure acting on the diaphragm changes when the circulation of both electrolytes is stopped, an excessive load may be applied to the diaphragm.

According to the operation method of the above redox flow battery based on the knowledge of the present inventors, the difference between the positive electrode solution and the negative electrode electrolyte is circulated in the cell stack and the circulation of both the electrolytes is stopped. Since the pressure state is maintained, the direction of the pressure acting on the diaphragm can be made constant. As a result, it is possible to suppress excessive stress from acting on the diaphragm, and to prevent the diaphragm from being damaged.
Here, the differential pressure state in which the pressure of one electrolyte acting on the diaphragm is higher than the pressure of the other electrolyte acting on the diaphragm is such that there is no substantial hindrance to the operation of the redox flow battery. The state in which the pressure of one electrolyte is higher than the pressure of the other electrolyte. The pressure difference between the two electrolytes can be set as appropriate according to the purpose. For example, before starting the operation of stopping the circulation of the electrolytic solution (during operation of the redox flow battery), the difference between the pressure of one electrolytic solution and the pressure of the other electrolytic solution can be 1000 Pa or more.

<2> As a method for operating the redox flow battery according to the embodiment, when the circulation of the positive electrode electrolyte and the negative electrode electrolyte is stopped, the rate of decrease in the circulation amount of the one electrolyte is changed to that of the other electrolyte. It is possible to use a mode in which the circulation rate of the both electrolytes is stopped simultaneously by increasing the rate of circulation rate reduction.

While maintaining the state where the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution as in the above embodiment, the decrease rate of the circulation amount of one electrolyte solution is set to the circulation amount of the other electrolyte solution. By making it larger than the decrease rate of, the circulation of both electrolytes can be stopped while gradually reducing the difference in the circulation amount of both electrolytes. As a result, since the stress acting on the diaphragm can be gradually reduced until the circulation of both electrolytes is stopped, damage to the diaphragm can be effectively prevented.

<3> As a method for operating the redox flow battery according to the embodiment, when the circulation of the positive electrode electrolyte and the negative electrode electrolyte is stopped, the rate of decrease in the circulation amount of the one electrolyte solution, A mode in which the rate of decrease in the circulation amount is adjusted and the circulation of the one electrolyte solution is stopped after the circulation of the other electrolyte solution can be exemplified.

As shown in the above embodiment, by stopping the circulation of one electrolytic solution after the circulation of the other electrolytic solution, the above differential pressure state is reliably maintained until the moment when the circulation of both electrolytic solutions is stopped. Can do.

<4> As an operating method of the redox flow battery according to the embodiment, an electrolytic solution tank provided in a circulation mechanism for circulating the one electrolytic solution is used as an electrolytic solution tank provided in a circulation mechanism for circulating the other electrolytic solution. The cell stack may be filled with both electrolytes when both electrolytes are not circulated.

According to the above embodiment, the differential pressure state can be maintained even when both electrolytes are not circulating. Also, if the differential pressure state is maintained when both electrolytes are not circulating, a device that circulates one electrolyte solution (for example, a liquid delivery device such as a pump) when recirculation of both electrolyte solutions is resumed. Even if the start-up is delayed from the start-up of the device that circulates the other electrolyte for some reason, it is difficult to achieve a reverse differential pressure state in which the pressure of the other electrolyte acting on the diaphragm is higher than the pressure of the one electrolyte.

<5> A redox flow battery according to an embodiment includes a cell stack in which a plurality of battery cells each having a positive electrode, a negative electrode, and a diaphragm, a positive electrode circulation mechanism for circulating a positive electrolyte in the cell stack, and the cell A redox flow battery comprising: a negative electrode circulation mechanism that circulates a negative electrode electrolyte in a stack. The redox flow battery includes the positive electrode circulation mechanism so that the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution from the circulation to the stop of the cathode electrolyte and the anode electrolyte. A flow rate controller for controlling the negative electrode circulation mechanism is provided.

According to the redox flow battery, the differential pressure state can be maintained both when the positive and negative electrolytes are circulated in the cell stack and when both the electrolytes are stopped. Therefore, the redox flow battery is a redox flow battery in which the direction of pressure acting on the diaphragm provided in the redox flow battery is constant and the diaphragm is not easily damaged.

[Details of the embodiment of the present invention]
Hereinafter, the operation method of the redox flow battery (RF battery) according to the embodiment and the embodiment of the RF battery will be described. In the embodiment, members indicated by the same reference numerals have the same function. In addition, this invention is not necessarily limited to the structure shown by embodiment, and is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.

<Embodiment 1>
≪Overall configuration of RF battery≫
As shown in the schematic diagram of FIG. 1, the RF battery 1 according to the present embodiment includes a cell stack 2, a positive electrode circulation mechanism 3P, and a negative electrode circulation mechanism 3N, as in the conventional RF battery. In FIG. 1, the configuration of the cell stack 2 is shown in a simplified manner, but actually, a configuration in which a plurality of sub-stacks 200 s are fastened with

end plates

210 and 220 as described with reference to the lower diagram of FIG. 15. It has. Moreover, although only one battery cell 100 is illustrated in the cell stack 2 of FIG. 1, a plurality of battery cells 100 are actually stacked. Each battery cell 100 includes a positive electrode 104, a negative electrode 105, and a diaphragm 101 that separates both

electrodes

104 and 105.

The positive electrode circulation mechanism 3 P includes a positive electrode tank 106, a positive electrode pipe line including a positive electrode forward pipe 108 and a positive electrode return pipe 110, and a pump (a positive electrode liquid feeding device) 112. The positive electrode forward pipe 108 is a pipe that supplies the positive electrode electrolyte from the positive electrode tank 106 to the cell stack 2, and the positive electrode return pipe 110 is a pipe that discharges the positive electrode electrolyte from the cell stack 2 to the positive electrode tank 106. . The pump 112 is a member that is provided in the middle of the positive electrode outward pipe 108 and that sends out the positive electrode electrolyte to the cell stack 2. In the case of such a configuration, the circulation amount of the positive electrode electrolyte can be changed by adjusting the output of the pump 112.

The negative electrode circulation mechanism 3 N includes a negative electrode tank 107, a negative electrode pipe composed of a negative electrode forward pipe 109 and a negative electrode return pipe 111, and a pump (negative electrode liquid feeding device) 113. The negative electrode forward pipe 109 is a pipe for supplying a negative electrode electrolyte from the negative electrode tank 107 to the cell stack 2, and the negative electrode return pipe 111 is a pipe for discharging the negative electrode electrolyte from the cell stack 2 to the negative electrode tank 107. . The pump 113 is a member that is provided in the middle of the negative electrode outgoing pipe 109 and that feeds the negative electrode electrolyte solution to the cell stack 2. In the case of such a configuration, the circulation amount of the negative electrode electrolyte can be changed by adjusting the output of the pump 113.

The main difference between the RF battery 1 of the embodiment having the above-described configuration and the conventional one is that the positive electrode electrolyte and the negative electrode electrolyte are circulated in the cell stack 2 and the circulation of both electrolytes is stopped. And a flow rate controller 5 for maintaining a first differential pressure state (a state in which the pressure acts in the direction of the filled arrow) in which the pressure of the positive electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the negative electrode electrolyte. It is.

≪Flow control part≫
The flow rate controller 5 is electrically connected to both the

pumps

112 and 113 so as to relatively control the output of the pump (liquid feeding device for positive electrode) 112 and the output of the pump (liquid feeding device for negative electrode) 113. Connected. The amount of electrolyte sent by each pump 112, 113 (that is, the amount of electrolyte circulated) varies according to the output of the

pumps

112, 113. In the case of the present embodiment, the positive electrode electrolyte that acts on the diaphragm 101 in the cell stack 2 by making the amount of the positive electrode electrolyte sent from the pump 112 larger than the amount of the negative electrode electrolyte sent from the pump 113. Creates a first differential pressure state in which the pressure of is higher than the pressure of the negative electrode electrolyte.

The flow controller 5 controls the

pumps

112 and 113 so that the first differential pressure state can be maintained even when the circulation of both electrolytes is stopped. Two typical control patterns will be described with reference to FIGS. 2 and 3 are graphs showing changes in the amount of liquid fed from the pumps 112 and 113 (that is, the amount of circulation of both electrolytes) from the state in which both electrolytes are circulated until the circulation is stopped. is there. 2 and 3, the vertical axis represents the amount of liquid fed from the

pumps

112 and 113, and the horizontal axis represents time. Further, the solid line in the graph indicates the amount of the positive electrode electrolyte supplied, and the dotted line indicates the amount of the negative electrode electrolyte supplied.

[Control pattern I]
As shown in the graph of FIG. 2, in the control pattern I, both electrolyte solutions are supplied at a time t0 from the state in which both electrolyte solutions are circulated with the amount of cathode electrolyte supplied larger than the amount of anode electrolyte supplied. Start to stop circulating. At this time, the rate of decrease in the amount (circulation amount) of the positive electrode electrolyte is set to be greater than the rate of decrease in the amount (circulation amount) of the negative electrode electrolyte. At time t1, the feeding of both electrolytes is stopped almost simultaneously.

According to the control pattern I, it is possible to stop the circulation of both electrolytic solutions while gradually reducing the difference between the feeding amounts (circulating amounts) of both electrolytic solutions. As a result, since the stress acting on the diaphragm 101 (see FIG. 1) can be gradually reduced until the circulation of both electrolytes is stopped, damage to the diaphragm 101 can be effectively prevented.

[Control Pattern II]
As shown in the graph of FIG. 3, also in the control pattern II, the circulation of both electrolytes starts to be stopped at time t0. Here, in the control pattern II, the rate of decrease in the amount (circulation amount) of the positive electrode electrolyte is substantially equal to the rate of decrease in the amount (circulation amount) of the negative electrode electrolyte. Originally, since the amount of the negative electrode electrolyte supplied was smaller than the amount of the positive electrode electrolyte supplied, when the rate of decrease in the amount of both electrolytes supplied was the same, the negative electrode electrolyte was supplied at time t2. After that, the feeding of the positive electrode electrolyte stops at time t3. That is, since the cathode electrolyte circulates in the cell stack 2 (see FIG. 1) even after the circulation of the anode electrolyte is stopped, the first difference is surely made until the moment when the circulation of both electrolytes is stopped. The pressure state can be maintained.

A plurality of valves exist in each of the positive electrode conduit and the negative electrode conduit of the RF battery 1 shown in FIG. In FIG. 1,

valves

114 and 116 are present in the positive line and

valves

115 and 117 are present in the negative line. The opening / opening / closing times of the valves 114 to 117 may be controlled by the flow control unit 5. By doing so, it becomes easy to perform the two control patterns.

≪Configuration related to circulation stop≫
Even after the circulation of both electrolytes is stopped by the control of the flow rate control unit 5 shown in FIG. 1, the first differential pressure state in which the pressure of the positive electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the negative electrode electrolyte is maintained. It is preferable to do. If the differential pressure state is maintained when both electrolytes are not circulated, when the circulation of both electrolytes is resumed, the start of the pump 112 that circulates the cathode electrolyte causes the anode electrolyte to circulate for some reason. This is because even if it is delayed from the start of the pump 113, it is difficult to achieve a reverse differential pressure state in which the pressure of the negative electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the positive electrode electrolyte.

In order to maintain the first differential pressure state when both the electrolytes are not circulated, for example, the positive electrode tank 106 may be disposed at a higher position than the negative electrode tank 107. Then, even after the circulation of both electrolytes is stopped, the cell stack 2 is filled with both electrolytes. By doing so, even if both electrolytes are not circulating, the first differential pressure state can be maintained by the potential energy.

≪Configuration to facilitate the formation of the first differential pressure state≫
In addition to the difference in the amount of liquid fed from the

pumps

112 and 113, the RF battery 1 may be provided with a first differential pressure forming mechanism for facilitating the formation of the first differential pressure state. The first differential pressure forming mechanism changes the configuration (mainly dimensions) of the existing members provided in the RF battery 1, and specifically provides a structural difference between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N. Can be formed. Hereinafter, an embodiment of the first differential pressure forming mechanism will be described with reference to FIGS. 4 to 6, the tank, the pump, and the valve are omitted, and in FIG. 7, the cell stack is also omitted.

[Formation of a differential pressure state due to the difference in length between the positive and negative electrode conduits]
FIG. 4 shows a differential pressure forming mechanism 6 A formed by making the positive return pipe 110 longer than the negative return pipe 111. When the tube is lengthened, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 4, the positive return pipe 110 is longer than the negative return pipe 111, so that the pressure loss of the positive return pipe 110 is larger than the pressure loss of the negative return pipe 111. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 becomes higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the negative electrode electrolyte. The differential pressure state can be created.

Although not shown in the drawings, the differential pressure forming mechanism 6A may be formed by making the negative electrode outward tube 109 longer than the positive electrode outward tube 108. In this case, the pressure of the negative electrode electrolyte in the cell stack 2 is lowered, and a state in which the pressure of the positive electrode electrolyte is relatively higher than the pressure of the negative electrode electrolyte is created. Of course, the differential pressure forming mechanism 6A can be formed by combining a configuration in which the lengths of the

return pipes

110 and 111 are different from a configuration in which the lengths of the

outgoing pipes

108 and 109 are different.

[Formation of a differential pressure state by the difference in thickness between the positive and negative electrode pipes]
FIG. 5 shows a differential pressure forming mechanism 6B formed by making the positive return pipe 110 thinner than the negative return pipe 111. When the tube is made thinner, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 5, the positive electrode return pipe 110 is made thinner than the negative electrode return pipe 111, so that the pressure loss of the positive electrode return pipe 110 is larger than the pressure loss of the negative electrode return pipe 111. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 becomes higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the negative electrode electrolyte. The differential pressure state can be created. When the differential pressure forming mechanism 6B is employed, the inner diameter of the positive return pipe 110 is preferably 80% or less of the inner diameter of the negative return pipe 111.

Although not shown, the differential pressure forming mechanism 6B may be formed by making the negative electrode outward tube 109 thinner than the positive electrode outward tube 108. In this case, the pressure of the negative electrode electrolyte in the cell stack 2 is lowered, and a state in which the pressure of the positive electrode electrolyte is relatively higher than the pressure of the negative electrode electrolyte is created. Of course, the differential pressure forming mechanism 6B can be formed by combining a configuration in which the

return pipes

110 and 111 have different thicknesses and a configuration in which the

forward pipes

108 and 109 have different thicknesses.

[Formation of the differential pressure state due to the difference between the positive and negative lines]
FIG. 6 shows a differential pressure forming mechanism 6 C formed by bending the positive return pipe 110 more complicatedly than the negative return pipe 111. If there are many bent portions of the tube, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 6, since the positive return pipe 110 is bent more complicatedly than the negative return pipe 111, the pressure loss of the positive return pipe 110 is larger than the pressure loss of the negative return pipe 111. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 becomes higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the negative electrode electrolyte. The differential pressure state can be created. In addition to increasing the number of bent portions of the tube, the tube can be bent in a complicated manner, for example, by reducing the bending radius of the bent portion of the tube.

Although not shown in the drawings, the differential pressure forming mechanism 6C may be formed by bending the negative electrode outward tube 109 more complicatedly than the positive electrode outward tube 108. Of course, the differential pressure forming mechanism 6C can be formed by combining a configuration in which the

return pipes

110 and 111 have different bending states and a configuration in which the

outgoing pipes

108 and 109 have different bending states.

[Differential pressure state formation due to different valve openings in the positive and negative lines]
A plurality of valves exist in each of the positive electrode conduit and the negative electrode conduit of the RF battery 1 shown in FIG. The valves 114 to 117 are used when stopping the circulation of the electrolyte solution to the cell stack 2. These valves 114 to 117 can be used to form a differential pressure forming mechanism. For example, the valve 116 of the positive return pipe 110 is throttled (the opening degree is made smaller) than the valve 117 of the negative return pipe 111, thereby reducing the pressure loss of the positive return pipe 110 to the pressure loss of the negative return pipe 111. Can be bigger. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 becomes higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the negative electrode electrolyte. The differential pressure state can be created.
The positions of the valves 114 to 117 are not limited to the positions shown in FIG. In FIG. 1, two valves exist in each of the positive electrode pipe and the negative electrode pipe, but the number of valves is not limited thereto. For example, each of the positive electrode conduit and the negative electrode conduit may include three or more valves, or one valve each.

The above-mentioned differential pressure state can also be created by lowering the pressure of the negative electrode electrolyte in the cell stack 2 by narrowing the valve 115 of the negative electrode outward tube 109 than the valve 114 of the positive electrode outward tube 108. Of course, a differential pressure forming mechanism is formed by combining a configuration in which the opening degrees of the

valves

116 and 117 of the

return pipes

110 and 111 are different from a configuration in which the opening degrees of the

valves

114 and 115 of the

outgoing pipes

108 and 109 are different. You can also.

[Formation of differential pressure state due to different configurations of positive and negative heat exchangers]
The RF battery 1 shown in FIG. 1 includes a positive electrode heat exchanger 4P provided in the middle of the positive electrode return pipe 110 and a negative electrode heat exchanger 4N provided in the middle of the negative electrode return pipe 111. The differential pressure forming mechanism 6D (see FIG. 7) can also be formed by these

heat exchangers

4P and 4N.

7 is a schematic configuration diagram of the negative electrode heat exchanger 4N, and a lower configuration of FIG. 7 is a schematic configuration diagram of the positive electrode heat exchanger 4P. The basic configuration of the heat exchanger is known as described in, for example, Japanese Patent Application Laid-Open No. 2013-206566. For example, as shown in FIG. 5, the heat exchanger 4P (4N) can be configured by placing a pipe 42P (42N) in a container 41P (41N) that stores the refrigerant 40P (40N). The pipe 42P (42N) is connected to the return pipe 110 (111), and therefore, the positive electrode electrolyte (the negative electrode electrolyte) flows therein. The positive electrode electrolyte (negative electrode electrolyte) is cooled by the refrigerant 40P (40N) while flowing through the pipe 42P (42N). The refrigerant 40P (40N) includes a gas refrigerant for air cooling and a liquid refrigerant for water cooling, and is cooled by a cooling mechanism (not shown). Here, the pipe 42P (42N) can be regarded as a part of the return pipe 110 (111).

When the differential pressure forming mechanism 6D is formed by the

heat exchangers

4P and 4N, the pipe 42P of the positive electrode heat exchanger 4P may be made longer than the pipe 42N of the negative electrode heat exchanger 4N as illustrated. By doing so, for the same reason as the differential pressure forming mechanism 6A in which the lengths of the

return pipes

110 and 111 are changed, the pressure difference of the positive electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the negative electrode electrolyte. Can produce.

In addition, the above-mentioned differential pressure state can also be created by making the pipe 42P thinner than the pipe 42N or by making the bent part of the pipe 42P more than the bent part of the pipe 42N. Of course, the differential pressure state may be created by combining the pipe length, the pipe thickness, and the bent state of the pipe. The differential pressure state can also be created by providing only the positive electrode heat exchanger 4P and not the negative electrode heat exchanger 4N.

[Other measures]
By arranging the positive electrode tank 106 in FIG. 1 higher than the negative electrode tank 107, the above-described differential pressure state can be formed. The differential pressure state can also be formed by routing the positive return pipe 110 to a position higher than the negative return pipe 111.

[About combination]
Each of the differential pressure forming mechanisms described above can be used alone or in combination. For example, when a configuration in which the lengths of the positive and negative electrode conduits are different from a configuration in which the thickness of the positive and negative electrode conduits are different, a desired differential pressure state is easily formed.

The first differential pressure state is preferably a differential pressure state in which the pressure of the positive electrode electrolyte acting on the diaphragm 101 over the entire surface of the diaphragm 101 is higher than the pressure of the negative electrode electrolyte. This is because even if the pressure of the positive electrode electrolyte immediately after being discharged from the cell stack is higher than the pressure of the negative electrode electrolyte, the pressure of the positive electrode electrolyte acting on the diaphragm locally on the surface of the diaphragm is This is because the pressure may be smaller than the pressure. With the above-described differential pressure forming mechanism, it is possible to create a differential pressure state in which the pressure of the positive electrode electrolyte acting on the diaphragm 101 over the entire surface of the diaphragm 101 is higher than the pressure of the negative electrode electrolyte.

[Effect of first differential pressure forming mechanism]
In the above-described embodiment, the flow path of the positive electrode electrolyte and the flow path of the negative electrode electrolyte in the cell stack 2 are the same in configuration, and a difference in configuration is provided between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N. Thus, a desired differential pressure state is formed. Therefore, a desired differential pressure state can be easily formed without disassembling the cell stack 2 by using the first differential pressure forming mechanism described above. On the other hand, when the flow path of the positive electrode electrolyte and the flow path of the negative electrode electrolyte in the cell frame in the cell stack are different as in the RF battery of Patent Document 1, for example, the electrolyte such as the type of the electrolyte When the flow conditions are changed, it is difficult to create a desired differential pressure state according to the change in the flow conditions. To make the cell frame suitable for the distribution conditions, it takes time to disassemble the cell stack, time to process the cell frame, time to assemble the cell stack again, and achieve the desired differential pressure state with the processed cell frame. This is because if it is not possible, further disassembly, processing, and assembly are required.

<Embodiment 2>
In Embodiment 2, the RF battery 1 shown in FIG. 1 acts on the diaphragm 101 both when the positive and negative electrolytes are circulated in the cell stack 2 and when the circulation of both electrolytes is stopped. A second differential pressure state in which the pressure of the negative electrode electrolyte is higher than the pressure of the positive electrode electrolyte (a state in which pressure acts on the diaphragm 101 in the direction of the white arrow in the battery cell 100 of FIG. 1) is maintained. An example will be described.

In the second differential pressure state, the flow rate control unit 5 controls the flow rate of the negative electrode electrolyte from the pump 113 of the negative electrode circulation mechanism 3N, and the flow rate of the positive electrode electrolyte from the pump 112 of the positive electrode circulation mechanism 3P. It is produced by making it bigger.

Further, the flow rate control unit 5 controls the

pumps

112 and 113 so that the second differential pressure state can be maintained even when the circulation of both electrolytes is stopped. Two typical control patterns will be described with reference to FIGS. The views of FIGS. 8 and 9 are the same as those of FIGS.

[Control Pattern III]
As shown in the graph of FIG. 8, in the control pattern III, both electrolyte solutions are supplied at a time t0 from the state in which both electrolyte solutions are circulated with the negative electrode electrolyte solution supplied larger than the positive electrode electrolyte supply amount. Start to stop circulating. At this time, the rate of decrease in the amount (circulation amount) of the negative electrode electrolyte is set to be greater than the rate of decrease in the amount (circulation amount) of the positive electrode electrolyte. At time t1, the feeding of both electrolytes is stopped almost simultaneously.

According to the control pattern III, the circulation of both electrolytes can be stopped while gradually reducing the difference in the amount (circulation amount) of both electrolytes. As a result, since the stress acting on the diaphragm 101 (see FIG. 1) can be gradually reduced until the circulation of both electrolytes is stopped, damage to the diaphragm 101 can be effectively prevented.

[Control Pattern IV]
As shown in the graph of FIG. 9, even in the control pattern IV, the circulation of both electrolytes starts to be stopped at time t0. Here, in the control pattern IV, the rate of decrease in the amount (circulation amount) of the positive electrode electrolyte is substantially the same as the rate of decrease in the amount (circulation amount) of the negative electrode electrolyte. Originally, since the amount of the positive electrode electrolyte supplied was smaller than the amount of the negative electrode electrolyte supplied, the rate of decrease in the amount of electrolyte supplied by both electrolytes was approximately the same. After that, the feeding of the negative electrode electrolyte stops at time t3. That is, since the negative electrode electrolyte circulates in the cell stack 2 (see FIG. 1) even after the circulation of the positive electrolyte is stopped, the second difference is surely ensured until the moment when the circulation of both electrolytes is stopped. The pressure state can be maintained.

Note that a plurality of valves exist in each of the positive electrode conduit and the negative electrode conduit of the RF battery 1 shown in FIG. In FIG. 1,

valves

114 and 116 are present in the positive line and

valves

≪Configuration related to circulation stop≫
Even after the circulation of both electrolytes is stopped by the control of the flow rate control unit 5 shown in FIG. 1, the second differential pressure state in which the pressure of the negative electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the positive electrode electrolyte is maintained. It is preferable to do. If the differential pressure state is maintained when both electrolytes are not circulated, when the circulation of both electrolytes is resumed, the start of the pump 113 that circulates the anode electrolyte causes the cathode electrolyte to circulate for some reason. This is because even if it is delayed from the start of the pump 112, it is difficult to achieve a reverse differential pressure state in which the pressure of the positive electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the negative electrode electrolyte.

In order to maintain the second differential pressure state when both the electrolytes are not circulated, for example, the negative electrode tank 107 may be disposed at a higher position than the positive electrode tank 106. Then, even after the circulation of both electrolytes is stopped, the cell stack 2 is filled with both electrolytes. By doing so, even if both electrolytes are not circulating, the second differential pressure state can be maintained by the potential energy.

≪Configuration to facilitate the formation of the second differential pressure state≫
In addition to the difference in the amount of liquid fed from the

pumps

112 and 113, the RF battery 1 may be provided with a second differential pressure forming mechanism for facilitating the formation of the second differential pressure state. The second differential pressure forming mechanism changes the configuration (mainly dimensions) of the existing members provided in the RF battery 1, and specifically provides a structural difference between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N. Can be formed. Hereinafter, an embodiment of the second differential pressure forming mechanism will be described with reference to FIGS. 10 to 12, the tank, pump, and valve are omitted, and in FIG. 13, the cell stack is also omitted.

[Formation of a differential pressure state due to the difference in length between the positive and negative electrode conduits]
FIG. 10 shows a differential pressure forming mechanism 6E formed by making the return pipe 111 for the negative electrode longer than the return pipe 110 for the positive electrode. When the tube is lengthened, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 10, the negative electrode return pipe 111 is longer than the positive electrode return pipe 110, so that the pressure loss of the negative electrode return pipe 111 is larger than the pressure loss of the positive electrode return pipe 110. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 becomes higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the positive electrode electrolyte. The differential pressure state can be created.

Although not shown, the differential pressure forming mechanism 6E may be formed by making the positive electrode outward tube 108 longer than the negative electrode outward tube 109. In this case, the pressure of the positive electrode electrolyte in the cell stack 2 is lowered, and a state in which the pressure of the negative electrode electrolyte is relatively higher than the pressure of the positive electrode electrolyte is created. Of course, the differential pressure forming mechanism 6A can be formed by combining a configuration in which the lengths of the

return pipes

110 and 111 are different from a configuration in which the lengths of the

outgoing pipes

108 and 109 are different.

[Formation of a differential pressure state by the difference in thickness between the positive and negative electrode pipes]
FIG. 11 shows a differential pressure forming mechanism 6 F formed by making the negative electrode return pipe 111 thinner than the positive electrode return pipe 110. When the tube is made thinner, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 11, the negative electrode return pipe 111 is made thinner than the positive electrode return pipe 110, so that the pressure loss of the negative electrode return pipe 111 is larger than the pressure loss of the positive electrode return pipe 110. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 becomes higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the positive electrode electrolyte. The differential pressure state can be created. When the differential pressure forming mechanism 6F is employed, the inner diameter of the negative electrode return pipe 111 is preferably 80% or less of the inner diameter of the positive electrode return pipe 110.

Although not shown, the differential pressure forming mechanism 6F may be formed by making the positive electrode outward tube 108 thinner than the negative electrode outward tube 109. In this case, the pressure of the positive electrode electrolyte in the cell stack 2 is lowered, and a state in which the pressure of the negative electrode electrolyte is relatively higher than the pressure of the positive electrode electrolyte is created. Of course, the differential pressure forming mechanism 6F can be formed by combining a configuration in which the

return pipes

110 and 111 have different thicknesses and a configuration in which the

forward pipes

108 and 109 have different thicknesses.

[Formation of the differential pressure state due to the difference between the positive and negative lines]
FIG. 12 shows a differential pressure forming mechanism 6G formed by bending the negative electrode return pipe 111 more complicatedly than the positive electrode return pipe 110. If there are many bent portions of the tube, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 12, the negative electrode return pipe 111 is bent more complicatedly than the positive electrode return pipe 110, so that the pressure loss of the negative electrode return pipe 111 is larger than the pressure loss of the positive electrode return pipe 110. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 becomes higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the positive electrode electrolyte. The differential pressure state can be created. In addition to increasing the number of bent portions of the tube, the tube can be bent in a complicated manner, for example, by reducing the bending radius of the bent portion of the tube.

Although not shown, the differential pressure forming mechanism 6G may be formed by bending the positive electrode outward tube 108 more complicatedly than the negative electrode outward tube 109. Of course, the differential pressure forming mechanism 6G can be formed by combining a configuration in which the

return pipes

110 and 111 have different bending states and a configuration in which the

outgoing pipes

108 and 109 have different bending states.

[Differential pressure state formation due to different valve openings in the positive and negative lines]
A plurality of valves exist in each of the positive electrode conduit and the negative electrode conduit of the RF battery 1 shown in FIG. The valves 114 to 117 are used when stopping the circulation of the electrolyte solution to the cell stack 2. These valves 114 to 117 can be used to form a differential pressure forming mechanism. For example, the valve 117 of the negative return pipe 111 is throttled (the opening degree is made smaller) than the valve 116 of the positive return pipe 110, thereby reducing the pressure loss of the negative return pipe 111 to the pressure loss of the positive return pipe 110. Can be bigger. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 becomes higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the diaphragm 101 in the cell stack 2 is higher than the pressure of the positive electrode electrolyte. The differential pressure state can be created.
The positions of the valves 114 to 117 are not limited to the positions shown in FIG. In FIG. 1, two valves exist in each of the positive electrode pipe and the negative electrode pipe, but the number of valves is not limited thereto. For example, each of the positive electrode conduit and the negative electrode conduit may include three or more valves, or one valve each.

The pressure difference of the positive electrode electrolyte in the cell stack 2 can be reduced by creating the valve 114 of the positive electrode outward pipe 108 smaller than the valve 115 of the negative electrode outgoing pipe 109. Of course, a differential pressure forming mechanism is formed by combining a configuration in which the opening degrees of the

valves

116 and 117 of the

return pipes

valves

114 and 115 of the

outgoing pipes

108 and 109 are different. You can also.

[Formation of differential pressure state due to different configurations of positive line heat exchanger and negative heat exchanger]
The RF battery 1 shown in FIG. 1 includes a positive electrode heat exchanger 4P provided in the middle of the positive electrode return pipe 110 and a negative electrode heat exchanger 4N provided in the middle of the negative electrode return pipe 111. The differential pressure forming mechanism 6H (see FIG. 13) can also be formed by these

heat exchangers

4P and 4N.

13 is a schematic configuration diagram of the negative electrode heat exchanger 4N, and a lower configuration of FIG. 13 is a schematic configuration diagram of the positive electrode heat exchanger 4P. The basic configuration of the heat exchanger is known as described in, for example, Japanese Patent Application Laid-Open No. 2013-206566. For example, as shown in FIG. 13, the heat exchanger 4P (4N) can be configured by placing a pipe 42P (42N) in a container 41P (41N) that stores the refrigerant 40P (40N). The pipe 42P (42N) is connected to the return pipe 110 (111), and therefore, the positive electrode electrolyte (the negative electrode electrolyte) flows therein. The positive electrode electrolyte (negative electrode electrolyte) is cooled by the refrigerant 40P (40N) while flowing through the pipe 42P (42N). The refrigerant 40P (40N) includes a gas refrigerant for air cooling and a liquid refrigerant for water cooling, and is cooled by a cooling mechanism (not shown). Here, the pipe 42P (42N) can be regarded as a part of the return pipe 110 (111).

When the differential pressure forming mechanism 6H is formed by the

heat exchangers

4P and 4N, the pipe 42N of the negative electrode heat exchanger 4N may be made longer than the pipe 42P of the positive electrode heat exchanger 4P as illustrated. By doing so, for the same reason as the differential pressure forming mechanism 6A in which the lengths of the

return pipes

110 and 111 are changed, the pressure difference of the negative electrode electrolyte acting on the diaphragm 101 is higher than the pressure of the positive electrode electrolyte. Can produce.

In addition, the above-mentioned differential pressure state can also be created by making the pipe 42N thinner than the pipe 42P, or by making the bent part of the pipe 42N more than the bent part of the pipe 42P. Of course, the differential pressure state may be created by combining the pipe length, the pipe thickness, and the bent state of the pipe. The above differential pressure state can also be created by providing only the negative electrode heat exchanger 4N and not the positive electrode heat exchanger 4P.

[Other measures]
The above-described differential pressure state can be formed by disposing the negative electrode tank 107 of FIG. 1 higher than the positive electrode tank 106. Further, the differential pressure state can also be formed by routing the negative electrode return pipe 111 to a position higher than the positive electrode return pipe 110.

It should be noted that the second differential pressure state is preferably a differential pressure state in which the pressure of the negative electrode electrolyte acting on the diaphragm 101 over the entire surface of the diaphragm 101 is higher than the pressure of the positive electrode electrolyte. Even if the pressure of the negative electrode electrolyte immediately after being discharged from the cell stack is higher than the pressure of the positive electrode electrolyte, the pressure of the negative electrode electrolyte acting on the diaphragm locally on the surface of the diaphragm is This is because the pressure may be smaller than the pressure. With the above-described differential pressure forming mechanism, it is possible to create a differential pressure state in which the pressure of the negative electrode electrolyte acting on the diaphragm 101 over the entire surface of the diaphragm 101 is higher than the pressure of the positive electrode electrolyte.

[Effect of second differential pressure forming mechanism]
In the above-described embodiment, the flow path of the positive electrode electrolyte and the flow path of the negative electrode electrolyte in the cell stack 2 are the same in configuration, and a difference in configuration is provided between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N. Thus, a desired differential pressure state is formed. Therefore, by utilizing the second differential pressure forming mechanism described above, a desired differential pressure state can be easily formed without disassembling the cell stack 2. On the other hand, when the flow path of the positive electrode electrolyte and the flow path of the negative electrode electrolyte in the cell frame in the cell stack are different as in the RF battery of Patent Document 1, for example, the electrolyte such as the type of the electrolyte When the flow conditions are changed, it is difficult to create a desired differential pressure state according to the change in the flow conditions. To make the cell frame suitable for the distribution conditions, it takes time to disassemble the cell stack, time to process the cell frame, time to assemble the cell stack again, and achieve the desired differential pressure state with the processed cell frame. This is because if it is not possible, further disassembly, processing, and assembly are required.

The redox flow battery and the operation method of the redox flow battery according to the present invention include stabilization of fluctuations in power generation output, power storage when surplus generated power, load leveling for new energy power generation such as solar power generation and wind power generation. In addition to being used for general power plants, it can also be used for instantaneous voltage drop countermeasures, power outage countermeasures, and load leveling.

1, α Redox flow battery (RF battery)
2 Cell stack 100 Battery cell 101 Diaphragm 102 Positive electrode part 103 Negative electrode part 104 Positive electrode 105

Negative electrode

3P, 100P Positive electrode circulation mechanism 106 Positive electrode tank 108 Positive electrode outward pipe 110 Positive electrode return pipe 112 Pump (liquid supply apparatus for positive electrode) 114 Valve for Positive Pipe for Outward Pipe 116

Valve

3N, 100N for Return Pipe for Positive Electrode Circulation Mechanism for Negative Electrode 107 Tank for Negative Electrode 109 Outbound Pipe for Negative Electrode 111 Pump for Negative Electrode 113 Pump (Liquid Feed Device for Negative Electrode) 115 Valve 117 Valve for negative electrode return pipe 4P Heat exchanger for positive electrode 40P Refrigerant 41P Container 42P Piping 4N Heat exchanger for negative electrode 40N Refrigerant 41N Container 42N Piping 5

Flow control units

6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H Differential pressure forming mechanism 120 Cell frame 121 Bipolar plate 122 Frame 1 3,124 supply fluid manifold 125,126 drainage manifold 127 seal member 190 feed and

discharge plate

210, 220 end plate 200 cell stack 200s sub-stack 230 clamping mechanism

Claims

Redox flow in which a positive electrode electrolyte is circulated using a positive electrode circulation mechanism and a negative electrode electrolyte is circulated in a cell stack in which a plurality of battery cells having positive electrodes, negative electrodes, and diaphragms are stacked. A battery operating method,
When circulating the positive electrode electrolyte and the negative electrode electrolyte to the cell stack, the circulation amount of one electrolyte solution is made larger than the circulation amount of the other electrolyte solution, and the one electrolyte solution acting on the diaphragm The pressure is set to a differential pressure state higher than the pressure of the other electrolyte acting on the diaphragm,
When the circulation amount of the positive electrode electrolyte and the negative electrode electrolyte is decreased and the circulation of both electrolytes is stopped, the circulation amount of the one electrolyte solution is made larger than the circulation amount of the other electrolyte solution. The operation method of the redox flow battery which maintains the said differential pressure state.
When stopping the circulation of the positive electrode electrolyte and the negative electrode electrolyte, the decrease rate of the circulation amount of the one electrolyte solution is made larger than the decrease rate of the circulation amount of the other electrolyte solution, The operation method of the redox flow battery according to claim 1, wherein the two are stopped simultaneously.
When stopping the circulation of the positive electrode electrolyte and the negative electrode electrolyte, the reduction rate of the circulation amount of the one electrolyte solution and the reduction rate of the circulation amount of the other electrolyte solution are adjusted,
The method for operating a redox flow battery according to claim 1, wherein the circulation of the one electrolytic solution is stopped after the circulation of the other electrolytic solution.
An electrolyte solution tank provided in a circulation mechanism for circulating the one electrolyte solution is disposed at a higher position than an electrolyte solution tank provided in the circulation mechanism for circulating the other electrolyte solution,
The operating method of the redox flow battery according to any one of claims 1 to 3, wherein the cell stack is filled with both electrolytes when both electrolytes are not circulating.
A cell stack in which a plurality of battery cells having a positive electrode, a negative electrode, and a diaphragm are stacked, a positive electrode circulation mechanism that circulates a positive electrode electrolyte in the cell stack, and a negative electrode circulation mechanism that circulates a negative electrode electrolyte in the cell stack A redox flow battery comprising:
The positive electrode circulation mechanism and the negative electrode circulation mechanism are arranged so that the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution between the circulation of the positive electrode electrolyte and the negative electrode electrolyte. A redox flow battery including a flow control unit for controlling.