TW201631831A - Redox-flow battery operation method and redox-flow battery - Google Patents

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 and a redox flow battery for use in an emergency voltage drop countermeasure, a power failure countermeasure, a load leveling, and the like.

An electrolyte circulating battery is one of the large-capacity batteries for storing so-called new energy sources such as solar power generation and wind power generation, and a representative one is a redox flow battery (RF battery). The RF battery is a battery that is charged and discharged by using a difference between the ion contained in the electrolyte solution for the positive electrode and the ion-reducing potential of the ion contained in the electrolyte solution for the negative electrode (see, for example, Patent Document 1). As shown in the operational principle diagram of the RF battery α shown in FIG. 14, the RF battery α includes a unit cell 100 in which the separator 101 through which hydrogen ions are transmitted is separated into the positive electrode portion 102 and the negative electrode portion 103. The positive electrode 104 is built in the positive electrode portion 102, and the positive electrode groove 106 for storing the positive electrode electrolyte solution is connected to the positive electrode return pipe 110 via the positive electrode vial 108. The positive electrode use pipe 108 is provided with a pump (positive liquid supply device) 112, and the constituent members 106, 108, 110, and 112 constitute a positive electrode circulation mechanism 100P for circulating the positive electrode electrolyte. Similarly, in the negative electrode portion 103 The negative electrode 105 is built in, and the negative electrode tank 107 for storing the negative electrode electrolyte solution is connected to the negative electrode return pipe 111 via the negative electrode use pipe 109. A pumping (negative liquid feeding device) 113 is provided in the negative electrode bypass pipe 109, and the negative electrode circulating mechanism 100N that circulates the negative electrode electrolytic solution is formed by the members 107, 109, 111, and 113. The electrolyte stored in each of the cells 106 and 107 is circulated in the cells 102 and 103 by the pumps 112 and 113 during charge and discharge. When charging and discharging are not performed, the pumps 112 and 113 are stopped, and the electrolytic solution is not circulated.

The above-described unit cell 100 is usually laminated in a plurality of structures inside a structure called a cell stack 200 as shown in FIG. The single cell stack 200 is a structure in which a laminated structure called a secondary single cell stack 200s is sandwiched between two end plates 210 and 220 on both sides thereof, and fastened by a fastening mechanism 230 (in the configuration of the figure, Use multiple sub-battery stacks for 200s). The secondary battery stack 200s is a top view shown in FIG. 15, and has a configuration in which a plurality of cells including the single cell frame 120, the positive electrode 104, the separator 101, the negative electrode 105, and the cell frame 120 are laminated. In the unit, the laminated body is sandwiched between the supply plates 190 and 190 (refer to the lower drawing of Fig. 15). The unit cell frame 120 provided in the unit cell is provided with a frame body 122 having a through window and a bipolar plate 121 that is filled with a through window, and is disposed so as to be in contact with the positive electrode 104 on one surface side of the bipolar plate 121. The negative electrode 105 is brought into contact on the other surface side of the bipolar plate 121. Under this configuration, one unit cell 100 is formed between the bipolar plates 121 of the adjacent unit cell frames 120.

Via the supply and discharge plates 190, 190 in the secondary single cell stack 200s The flow of the electrolytic solution to the unit cell 100 is performed by the liquid supply manifolds 123 and 124 formed in the casing 122 and the liquid discharge manifolds 125 and 126. The electrolyte solution for the positive electrode is supplied from the liquid supply manifold 123 to the positive electrode 104 via the inlet slit formed on one surface side (paper front surface) of the housing 122, and is formed through the outlet slit formed in the upper portion of the housing 122. It is discharged by the drain manifold 125. Similarly, the electrolyte solution for the negative electrode is supplied from the liquid supply manifold 124 to the negative electrode 105 via an inlet slit (indicated by a dotted line) formed on the other surface side (back surface of the paper) of the casing 122, and is formed in the frame. The outlet slit (indicated by a dotted line) of the upper portion of the body 122 is discharged by the drain manifold 126. An annular sealing member 127 such as an O-ring or a flat gasket is disposed between the unit cell frames 120 to suppress leakage of the electrolyte from the secondary cell stack 200s.

The electric power input and output between the unit cell 100 and the external device provided in the secondary cell stack 200s is performed by using a current collecting structure under a current collector plate made of a conductive material. The current collector plate is provided with a pair of battery cells 200s each, and each of the current collector plates is electrically connected to the bipolar plate 121 of the cell frame 120 located at both ends in the stacking direction among the plurality of laminated battery cells 120.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2013-80613

In the operation of the redox flow battery, there is a demand that one of the pressure of the positive electrode electrolyte acting on the separator in the cell stack and the pressure of the negative electrode electrolyte is higher than the other. According to the review by the present inventors, it has been found that when the circulation of the two electrolytes is stopped, it is preferable to maintain the pressure of one of the electrolyte solutions higher than the pressure of the other electrolyte solution. In addition, it is necessary to rely on the case of which person's pressure is high.

The present invention has been made in view of the above circumstances, and one of its objects is to provide a method for operating a redox flow battery and a redox flow battery in which the circulation of the positive electrode electrolyte and the negative electrode electrolyte is stopped. In the period until the other, the pressure of the positive electrode electrolyte acting on the separator in the cell stack 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 one aspect of the present invention is a method for operating a redox flow battery in which a plurality of single cell stacks having a positive electrode, a negative electrode, and a separator are laminated. The positive electrode electrolyte is circulated by the circulation mechanism of the positive electrode, and the negative electrode electrolyte is circulated by using the circulation mechanism for the negative electrode. In the method for operating a redox flow battery, when the positive electrode electrolyte and the negative electrode electrolyte are circulated in the cell stack, the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution. And the pressure ratio of the one of the electrolytes acting on the separator is applied to the aforementioned separator In the differential pressure state in which the pressure of the other electrolyte solution is high, the circulation amount of the positive electrode electrolyte solution and the negative electrode electrolyte solution is reduced, and when the circulation of the two electrolyte solutions is stopped, the circulation amount of the one electrolyte solution is still higher than the above-described other One of the electrolytes has a large amount of circulation, and the differential pressure state is maintained.

Further, the redox flow battery according to one aspect of the present invention includes the following redox flow battery: a single cell stack in which a plurality of cells including a positive electrode, a negative electrode, and a separator are laminated; a circulation mechanism for the positive electrode that circulates the positive electrode electrolyte; and a circulation mechanism for the negative electrode that circulates the negative electrode electrolyte in the single cell stack. The redox flow battery includes a flow rate control unit that is configured such that the circulation of one of the positive electrode electrolyte and the negative electrode electrolyte is stopped until the other electrolyte is discharged. The positive electrode circulation mechanism and the negative electrode circulation mechanism are controlled in such a manner that the circulation amount of the liquid is large.

In the method of operating the redox flow battery and the redox flow battery, the positive electrode electrolyte of the separator acting in the cell stack can be made while the positive electrode electrolyte and the negative electrode electrolyte are circulated until the cycle is stopped. Either one of the pressure and the pressure of the negative electrode electrolyte is higher than the other.

1. α‧‧‧ Redox flow battery (RF battery)

2‧‧‧Single cell stack

100‧‧‧single battery

101‧‧‧Separator

102‧‧‧ positive part

103‧‧‧Negative part

104‧‧‧positive electrode

105‧‧‧Negative electrode

3P, 100P‧‧‧ positive circulation mechanism

106‧‧‧ positive slot

108‧‧‧ Positive pipe for the anode

110‧‧‧Return tube for positive electrode

112‧‧‧Pump (positive liquid feeding device)

114‧‧‧Positive valve for the anode

116‧‧‧Return valve for positive pole

3N, 100N‧‧‧Circular mechanism for negative electrodes

107‧‧‧Negative tank

109‧‧‧Anode for negative electrode

111‧‧‧Return tube for negative electrode

113‧‧‧Pump (negative liquid feeding device)

115‧‧‧Return valve for the anode

117‧‧‧Return valve for the anode

4P‧‧‧ Positive heat exchanger

40P‧‧‧Refrigerant

41P‧‧‧ Container

42P‧‧‧Pipe

4N‧‧‧Negative heat exchanger

40N‧‧‧Refrigerant

41N‧‧‧ Container

42N‧‧‧Pipe

5‧‧‧Flow Control Department

6A, 6B, 6C, 6D, 6E, 6F, 6G, 6H‧‧‧ differential pressure forming mechanism

120‧‧‧single battery frame

121‧‧‧ bipolar plates

122‧‧‧ frame

123, 124‧‧‧liquid supply manifold

125, 126‧‧ ‧ drainage manifold

127‧‧‧Seal components

190‧‧‧ supply plates

210, 220‧‧‧ end plates

200‧‧‧single battery stack

200s‧‧‧ single cell stack

230‧‧‧ fastening mechanism

Fig. 1 is a schematic configuration diagram of a redox flow battery according to an embodiment.

[Fig. 2] A graph relating to the control mode I for stopping the circulation of the positive electrode electrolyte and the negative electrode electrolyte.

[Fig. 3] A graph relating to the control mode II for stopping the circulation of the positive electrode electrolyte and the negative electrode electrolyte.

[Fig. 4] A schematic configuration diagram of a differential pressure forming mechanism configured by making a positive electrode returning pipe longer than a negative electrode returning pipe.

FIG. 5 is a schematic configuration diagram of a differential pressure forming mechanism configured by making a positive electrode returning pipe thinner than a negative electrode returning pipe.

FIG. 6 is a schematic configuration diagram of a differential pressure forming mechanism configured by bending a positive electrode returning pipe more complicatedly than a negative electrode returning pipe.

FIG. 7 is a schematic configuration diagram of a differential pressure forming mechanism configured by a heat exchanger for a positive electrode and a heat exchanger for a negative electrode.

[Fig. 8] A graph relating to the control mode III for stopping the circulation of the positive electrode electrolyte and the negative electrode electrolyte.

[Fig. 9] A graph relating to the control mode IV for stopping the circulation of the positive electrode electrolyte and the negative electrode electrolyte.

FIG. 10 is a schematic configuration diagram of a differential pressure forming mechanism configured by making a negative electrode returning tube longer than a positive electrode returning pipe.

FIG. 11 is a schematic configuration diagram of a differential pressure forming mechanism configured by making a negative electrode returning pipe thinner than a positive electrode returning pipe.

FIG. 12 is a schematic configuration diagram of a differential pressure forming mechanism configured by bending a negative electrode returning tube more complicatedly than a positive electrode returning pipe.

[Fig. 13] A schematic configuration diagram of a differential pressure forming mechanism configured by a heat exchanger for a positive electrode and a heat exchanger for a negative electrode.

Fig. 14 is a schematic view showing the operation of a redox flow battery.

Fig. 15 is a schematic configuration diagram of a single cell stack.

[Description of Embodiments of the Present Invention]

First, the contents of the embodiments of the present invention will be described first.

<1> A method of operating a redox flow battery according to an embodiment is a method of operating a redox flow battery in which a plurality of single cell stacks having a positive electrode, a negative electrode, and a separator are laminated. The positive electrode electrolyte is circulated by the circulation mechanism of the positive electrode, and the negative electrode electrolyte is circulated by using the circulation mechanism for the negative electrode. In the method of operating the redox flow battery, when the positive electrode electrolyte and the negative electrode electrolyte are circulated in the cell stack, the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution. The pressure of the one of the electrolytes acting on the separator is higher than the pressure of the other electrolyte that acts on the separator, and the amount of circulation of the cathode electrolyte and the anode electrolyte is reduced. When the circulation of the two electrolytes is stopped, the circulation amount of the one electrolyte solution is increased more than the circulation amount of the other electrolyte solution, and the differential pressure state is maintained.

When one of the pressure of the positive electrode electrolyte and the pressure of the negative electrode electrolyte in the cell stack is higher than the other, it becomes a single cell The pressure of one of the electrolytes in the separator in the stack is higher than the pressure of the other electrolyte acting on the separator. According to the review by the present inventors, it has been found that when the differential pressure state is maintained while circulating the two electrolytes, it is preferable to maintain the differential pressure state when the circulation of the two electrolytes is stopped. The reason is that when the direction of the pressure acting on the diaphragm changes when the circulation of the two electrolytes is stopped, there is an excessive load applied to the diaphragm.

According to the method for operating the redox flow battery discovered by the present inventors, when the circulation of the positive electrode electrolyte and the negative electrode electrolyte is circulated in the cell stack, the differential pressure is maintained when the circulation of the two electrolytes is stopped. The state is such that the direction of the pressure acting on the diaphragm is fixed. As a result, it is possible to suppress excessive stress applied to the separator and prevent damage of the separator.

Here, the pressure of the electrolytic solution that acts on the separator becomes a differential pressure state higher than the pressure of the other electrolytic solution that acts on the separator, and refers to a state that does not occur during the operation of the redox flow battery. To the extent that a substantial obstacle occurs, the pressure of one of the electrolytes is higher than the pressure of the other electrolyte. The difference in pressure between the two electrolytes can be appropriately set depending on the purpose. For example, before the operation to stop the circulation of the electrolytic solution (during the operation of the redox flow battery), the difference between the pressure of one of the electrolytic solutions and the pressure of the other electrolytic solution may be 1000 Pa or more.

(2) In the method of 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 circulation rate of the one electrolyte solution is decreased. The rate of decrease in the circulation amount of the other electrolyte solution is larger than that of the other electrolyte solution, and the circulation of the two electrolyte solutions is simultaneously stopped.

In the above-described embodiment, the circulation amount of one of the electrolytic solutions is maintained to be larger than the circulation amount of the other electrolytic solution, and the rate of decrease in the circulation amount of one of the electrolytic solutions is larger than the decrease rate of the circulation amount of the other electrolytic solution. Therefore, the difference in the circulation amount of the two electrolytes can be gradually reduced while the circulation of the two electrolytes is stopped. As a result, the stress acting on the separator can be gradually reduced during the period in which the circulation of the two electrolyte solutions is stopped, so that the damage of the separator can be effectively prevented.

(3) In the method of 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 circulation rate of the one electrolyte solution is decreased. The rate of decrease in the circulation amount of the other electrolytic solution is adjusted so that the circulation of the one of the electrolytic solutions is stopped later than the circulation of the other electrolytic solution.

As shown in the above aspect, the circulation of one of the electrolytic solutions is stopped later than the circulation of the other electrolytic solution, and the differential pressure state can be surely maintained until the cycle of stopping the circulation of the two electrolytic solutions.

<4> In the method of operating the redox flow battery according to the embodiment, the tank of the electrolytic solution provided in the circulation mechanism that circulates the one of the electrolytes is disposed in comparison with the other one. The liquid circulation cycle mechanism has a groove height position of the electrolyte, and when the two electrolytes are not circulated, the two cell electrolytes are filled in the cell stack.

According to the above aspect, when the two electrolytes are not circulated, the differential pressure state can be maintained. In addition, as long as the two electrolytes are not circulated, the differential pressure state is maintained, and when the circulation of the two electrolytes is restarted, even one of the electrolytes is followed. The activation of the device of the ring (for example, a liquid feeding device such as a pump) is not so long as the start of the device for circulating the other electrolyte solution, and it is difficult to become the pressure of the other electrolyte acting on the diaphragm. A state of a differential pressure higher than the pressure of one of the electrolytes.

<5> The redox flow battery according to the embodiment includes the following redox flow battery: a single cell stack in which a plurality of cells having a positive electrode, a negative electrode, and a separator are laminated; a circulation mechanism for the positive electrode in which the positive electrode electrolyte is circulated; and a circulation mechanism for the negative electrode in which the negative electrode electrolyte is circulated in the single cell stack. The redox flow battery includes a flow rate control unit that is configured such that the circulation of one of the positive electrode electrolyte and the negative electrode electrolyte is stopped until the other electrolyte is discharged. The positive electrode circulation mechanism and the negative electrode circulation mechanism are controlled in such a manner that the circulation amount of the liquid is large.

According to the above-described redox flow battery, when the circulation of the positive electrode electrolyte and the negative electrode electrolyte is performed in the cell stack, the differential pressure state can be maintained when the circulation of the two electrolyte solutions is stopped. Therefore, the above-described redox flow battery is a redox flow battery in which the direction of the pressure of the separator provided in the redox flow battery is fixed and the diaphragm is hard to be damaged.

[Details of Embodiments of the Present Invention]

Hereinafter, an operation method of a redox flow battery (RF battery) according to an embodiment and an embodiment of an RF battery will be described. In the embodiment, members having the same reference numerals have the same functions. another The present invention is not limited to the embodiments shown in the embodiments, and is intended to include all modifications within the meaning and scope of the claims.

<Embodiment 1> "The overall composition of the RF battery"

As shown in the schematic diagram of Fig. 1, the RF battery 1 according to the present embodiment is a conventional RF battery, and includes a cell stack 2, a positive circulating mechanism 3P, and a negative circulating mechanism 3N. In FIG. 1, the configuration of the cell stack 2 is simplified, but it is actually described with reference to the lower diagram of FIG. 15, and the plurality of secondary cell stacks 200s are provided as end plates 210 and 220. And the composition of the fastening. Further, in the cell stack 2 of FIG. 1, only one cell 100 is illustrated, but a plurality of cells 100 are actually stacked. Each of the unit cells 100 is configured by a positive electrode 104, a negative electrode 105, and a separator 101 that separates the two electrodes 104 and 105.

The positive electrode circulation mechanism 3P includes a positive electrode tank 106, a positive electrode via 108 and a positive electrode return pipe 110, and a pump (positive liquid supply device) 112. The positive electrode use pipe 108 is a pipe for supplying 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 for discharging the positive electrode electrolyte from the cell stack 2 to the positive electrode tank 106. The pump 112 is a member made of a member provided in the middle of the positive electrode bypass pipe 108, and sends 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 adjusted by adjusting the output of the pump 112.

The negative-electrode circulation mechanism 3N includes a negative-electrode groove 107, a negative-electrode via 109 and a negative-electrode return pipe 111, and a pump (negative liquid supply device) 113. The negative electrode bypass 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 which is provided in the middle of the negative electrode bypass pipe 109, and sends the negative electrode electrolyte to the cell stack 2. In the case of such a configuration, the circulation amount of the negative electrode electrolyte can be adjusted in accordance with the output of the pump 113.

The main difference between the RF battery 1 having the above-described configuration and the conventional one is that a flow rate control unit 5 for circulating the positive electrode electrolyte and the negative electrode electrolyte in the cell stack 2 is provided. At the time of stopping the circulation of the two electrolytes, the first differential pressure state in which the pressure of the positive electrode electrolyte acting on the separator 101 is higher than the pressure of the negative electrode electrolyte (the state in which the pressure acts in the direction in which the arrow is applied) is maintained.

Flow Control Department

The flow rate control unit 5 is electrically connected to the two pumps 112 and 113 so as to relatively control the output of the pump (positive liquid supply device) 112 and the output of the pump (negative liquid supply device) 113. . The liquid supply amount of the electrolytic solution of each of the pumps 112 and 113 (that is, the circulation amount of the electrolytic solution) changes depending on the output of the pumps 112 and 113. In the case of the present embodiment, the amount of liquid supplied from the positive electrode electrolyte of the pump 112 is made larger than the amount of liquid to be supplied from the negative electrode electrolyte of the pump 113, thereby acting on the single cell stack. The pressure of the positive electrode electrolyte of the separator 101 in 2 is higher than the pressure of the negative electrode electrolyte in a first differential pressure state.

The flow rate control unit 5 controls the pumps 112 and 113 so that the first differential pressure state can be maintained even when the circulation of the two electrolytes is stopped. The two representative control modes will be described with reference to Figs. 2 and 3 . 2 and 3 are diagrams showing changes in the amount of liquid supplied from the pumps 112 and 113 (that is, the circulation amount of the two electrolytes) from the state in which the two electrolytes are circulated to the period in which the circulation is stopped. Graphics. The vertical axes of the graphs of Figs. 2 and 3 are the amount of liquid supplied from the pumps 112 and 113, and the horizontal axis is the time. Further, the solid line in the graph indicates the liquid amount of the positive electrode electrolyte, and the dotted line indicates the liquid amount of the negative electrode electrolyte.

[Control Mode I]

As shown in the graph of Fig. 2, in the control mode I, the two electrolyte solutions are circulated at a time t0 from a state in which the amount of liquid supplied from the positive electrode electrolyte is larger than the amount of liquid supplied from the negative electrode electrolyte to circulate the two electrolytes. Start to stop. In this case, the rate of decrease in the amount of liquid to be supplied (the amount of circulation) of the positive electrode electrolyte is made larger than the rate of decrease in the amount of liquid to be supplied (the amount of circulation of the negative electrode electrolyte). Further, at time t1, the liquid supply of the two electrolytes is stopped almost simultaneously.

According to the above control mode I, the difference in the amount of liquid supply (circulation amount) between the two electrolytes can be gradually reduced while the circulation of the two electrolytes is stopped. As a result, the stress acting on the separator 101 (refer to FIG. 1) can be gradually reduced during the period in which the circulation of the two electrolyte solutions is stopped, so that the damage of the separator 101 can be effectively prevented.

[Control Mode II]

As shown in the graph of Fig. 3, in the control mode II, the cycle of the two electrolytes is also stopped at time t0. Here, in the control mode II, the rate of decrease in the amount of liquid to be supplied (the amount of circulation) of the positive electrode electrolyte is the same as the rate of decrease in the amount of liquid to be supplied (the amount of circulation of the negative electrode electrolyte). Originally, the liquid supply amount of the negative electrode electrolyte solution is smaller than the liquid supply amount of the positive electrode electrolyte solution. Therefore, when the rate of decrease in the liquid supply amount of the two electrolyte solutions is the same, the liquid supply of the negative electrode electrolyte solution is stopped at time t2, and thereafter at the time. The liquid supply of the t3 positive electrolyte is stopped. That is, after the circulation of the negative electrode electrolyte is stopped, the positive electrode electrolyte is still circulated in the cell stack 2 (see FIG. 1), so that the first differential pressure state can be surely maintained until the cycle of stopping the two electrolytes.

Further, each of the positive electrode piping and the negative electrode piping of the RF battery 1 shown in Fig. 1 has a plurality of valves. In Fig. 1, valves 114 and 116 are present in the positive electrode line, and valves 115 and 117 are present in the negative electrode line. The flow rate control unit 5 may control the opening/opening and closing times of the valves 114 to 117. By adopting this method, it is easy to carry out the above two control modes.

"Related composition when the cycle stops"

It is preferable to maintain the first differential pressure state in which the pressure of the positive electrode electrolyte acting on the separator 101 is higher than the pressure of the negative electrode electrolyte after the circulation of the two electrolytes is stopped by the control of the flow rate control unit 5 of Fig. 1 . The reason is that as long as the two electrolytes are not circulated, the differential pressure state is maintained, so that the two electrolytes At the start of the cycle, even if the activation of the pump 112 for circulating the positive electrode electrolyte is later than the start of the pump 113 for circulating the negative electrode electrolyte for some reason, it is difficult to become the negative electrode electrolyte acting on the separator 101. The pressure is changed to a higher differential pressure than the pressure of the positive electrode electrolyte.

When the circulation of the two electrolytes is maintained in the first differential pressure state, the positive electrode tank 106 is disposed at a position higher than the negative electrode tank 107, for example. Further, after the circulation of the two electrolytes is stopped, the two electrolytes are filled in the cell stack 2. By adopting this method, even if the two electrolytes are not circulated, the first differential pressure state can be maintained by the borrowing amount.

"In order to make the formation of the first differential pressure state easier"

In addition to the difference in the amount of liquid supplied from the pumps 112 and 113, a first differential pressure forming mechanism for facilitating the formation of the first differential pressure state may be provided in the RF battery 1. The first differential pressure forming means can be formed by changing the configuration (mainly size) of the existing material provided in the RF battery 1. Specifically, the difference in composition can be set for the positive circulating mechanism 3P and the negative circulating mechanism 3N. Thereby formed. Hereinafter, an embodiment of the first differential pressure forming mechanism will be described with reference to Figs. 4 to 7 . The grooves, pumps, and valves are omitted in FIGS. 4 to 6, and the single cell stack is omitted in FIG.

[Formation of differential pressure state due to the difference in length between the positive electrode tube and the negative electrode tube]

FIG. 4 shows a differential pressure forming mechanism 6A formed by making the positive electrode returning pipe 110 longer than the negative electrode returning pipe 111. Flowing in the tube when growing the tube The pressure loss of the electrolyte in the column increases. In the case of FIG. 4, since the positive electrode return pipe 110 is longer than the negative electrode return pipe 111, the pressure loss of the positive electrode return pipe 110 is larger than the negative pressure return pipe 111. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 is higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the negative electrode electrolyte. A differential pressure state.

Although not shown, the negative electrode passage pipe 109 may be longer than the positive electrode use pipe 108 to form the differential pressure forming mechanism 6A. In this case, the state is established in which the pressure of the negative electrode electrolyte in the cell stack 2 is lowered, and the pressure of the positive electrode electrolyte solution is higher than the pressure of the negative electrode electrolyte solution. Needless to say, the differential pressure forming mechanism 6A may be formed by combining the configurations in which the lengths of the return pipes 110 and 111 are different and the configurations in which the lengths of the outward pipes 108 and 109 are different.

[Formation of differential pressure state due to the difference in thickness between the positive electrode tube and the negative electrode tube]

FIG. 5 shows a differential pressure forming mechanism 6B formed by making the positive electrode returning pipe 110 thinner than the negative electrode returning pipe 111. When the tube is refined, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 5, since the positive electrode return pipe 110 is thinner than the negative electrode return pipe 111, the pressure loss of the positive electrode return pipe 110 is larger than the negative pressure return pipe 111. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 is higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the negative electrode electrolyte. A differential pressure state. Pick In the case of the differential pressure forming mechanism 6B, it is preferable that the inner diameter of the positive electrode returning pipe 110 is 80% or less of the inner diameter of the negative electrode returning pipe 111.

Although not shown, the negative electrode passage pipe 109 may be thinner than the positive electrode use pipe 108 to form the differential pressure forming mechanism 6B. In this case, the state is established in which the pressure of the negative electrode electrolyte in the cell stack 2 is lowered, and the pressure of the positive electrode electrolyte solution is higher than the pressure of the negative electrode electrolyte solution. Needless to say, the differential pressure forming mechanism 6B may be formed by combining the configurations in which the thicknesses of the return pipes 110 and 111 are different and the configurations in which the thicknesses of the outward pipes 108 and 109 are different.

[Formation of differential pressure state due to the difference in the path between the positive electrode tube and the negative electrode tube]

FIG. 6 shows a differential pressure forming mechanism 6C formed by bending the positive electrode returning pipe 110 more than the negative electrode returning pipe 111. When the bending of the tube is excessive, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 6, the positive electrode return pipe 110 is more complicatedly bent than the negative electrode return pipe 111, so that the pressure loss of the positive electrode return pipe 110 is larger than the negative pressure return pipe 111. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 is higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the negative electrode electrolyte. A differential pressure state. In addition, in addition to increasing the bend of the tube, for example, by narrowing the bending radius of the bend of the tube, the tube can be complicatedly bent.

Although not shown, the anode for the negative electrode 109 is used for the positive electrode. It is also possible that the outward pipe 108 is more complicatedly bent to form the differential pressure forming mechanism 6C. Needless to say, the differential pressure forming mechanism 6C may be formed by combining the configurations in which the bending states of the return pipes 110 and 111 are different and the configurations in which the bending states of the outward pipes 108 and 109 are different.

[Formation of differential pressure state due to the difference in opening degree of the valve for the positive electrode and the valve for the negative electrode]

Each of the positive electrode conduit and the negative electrode conduit of the RF battery 1 shown in Fig. 1 has a plurality of valves. The valves 114 to 117 are used to stop the circulation of the electrolytic solution to the cell stack 2, and the like. The differential pressure forming mechanism can also be formed by using these valves 114 to 117. For example, the valve 116 of the positive electrode return pipe 110 is compressed (reduced opening degree) than the valve 117 of the negative return pipe 111, so that the pressure loss of the positive electrode return pipe 110 can be made larger than that of the negative return pipe 111. The pressure loss is large. As a result, the pressure of the positive electrode electrolyte in the cell stack 2 is higher than the pressure of the negative electrode electrolyte, and the pressure of the positive electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the negative electrode electrolyte. A differential pressure state.

Further, the positions of the valves 114 to 117 are not limited to the positions shown in Fig. 1 . In addition, in FIG. 1, although there are two valves in each of the positive electrode line and the negative electrode line, the number of valves is not limited to this. For example, each of the positive electrode conduit and the negative electrode conduit may have three or more valves, or one valve may be provided.

The valve 115 of the anode bypass pipe 109 is compressed by the valve 114 of the anode bypass pipe 108, and the negative electrode in the cell stack 2 can also be electrically charged. The pressure of the solution is lowered, and the above differential pressure state is made. Needless to say, the difference in the opening degrees of the valves 116 and 117 of the return pipes 110 and 111 and the different degrees of opening of the valves 114 and 115 of the outward pipes 108 and 109 may be combined to form a differential pressure forming mechanism.

[Formation of differential pressure state due to difference in configuration of heat exchanger for positive electrode and heat exchanger for negative electrode]

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 the heat exchangers 4P and 4N.

A schematic configuration diagram of the negative electrode heat exchanger 4N is shown in the upper part of FIG. 7, and a schematic configuration diagram of the positive electrode heat exchanger 4P is shown in the lower part of FIG. The basic configuration of the heat exchanger is known, for example, from Japanese Patent Laid-Open Publication No. 2013-206566. For example, as shown in Fig. 5, the pipe 42P (42N) can be climbed in the container 41P (41N) in which the refrigerant 40P (40N) is stored to constitute the heat exchanger 4P (4N). Since the piping 42P (42N) is connected to the return pipe 110 (111), the positive electrode electrolyte (negative electrode electrolyte) flows through the inside. 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) is a liquid 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 piping 42P of the positive electrode heat exchanger 4P may be longer than the piping 42N of the negative electrode heat exchanger 4N. By this means, the pressure of the positive electrode electrolyte acting on the separator 101 can be made higher than the pressure of the negative electrode electrolyte for the same reason as the differential pressure forming mechanism 6A which changes the length of the return pipes 110 and 111. Pressure state.

Further, the pipe 42P is made thinner than the pipe 42N, or the pipe 42P is bent more than the pipe 42N, so that the above-described differential pressure state can be made. Of course, the differential pressure state may be made by combining the length of the pipe, the thickness of the pipe, and the bending state of the pipe. Further, only the positive electrode heat exchanger 4P is provided, and the negative electrode heat exchanger 4N is not provided, so that the above-described differential pressure state can be made.

[other policy]

The positive electrode groove 106 of FIG. 1 may be disposed higher than the negative electrode groove 107 to form the above-described differential pressure state. Further, the positive electrode return pipe 110 may be positioned higher than the negative electrode return pipe 111 to form the differential pressure state.

[about combination]

Each of the differential pressure forming mechanisms described above may be used singly or in combination. For example, when the configuration in which the lengths of the positive electrode tubes and the negative electrode tubes are different, and the configuration in which the positive electrode tubes and the negative electrode tubes are different in thickness are combined, it is easy to form a desired differential pressure state.

In addition, the first differential pressure state is throughout the entire diaphragm 101 The surface is a differential pressure state in which the pressure of the positive electrode electrolyte acting on the separator 101 is higher than the pressure of the negative electrode electrolyte. The reason for this is that 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 partially acting on the separator on the surface of the separator is lower than that of the negative electrode. The pressure of the electrolyte is small. According to the above-described differential pressure forming mechanism, the differential pressure state in which the pressure of the positive electrode electrolyte acting on the separator 101 is higher than the pressure of the negative electrode electrolyte can be made over the entire surface of the separator 101.

[Effect of the first differential pressure forming mechanism]

In the above-described embodiment, the flow path of the positive electrode electrolyte in the cell stack 2 is the same as that of the negative electrode electrolyte, and the difference between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N is set. A desired differential pressure state is formed. Therefore, with the first differential pressure forming mechanism described above, it is possible to easily form a desired differential pressure state without decomposing the cell stack 2. On the other hand, in the RF battery of Patent Document 1, when the flow path of the positive electrode electrolyte of the cell frame in the cell stack is different from the flow path of the negative electrode electrolyte, for example, electrolysis of the type of the electrolyte or the like is performed. When the flow conditions of the liquid change, it is difficult to make a desired differential pressure state in accordance with the change in the flow conditions. The reason is that it is necessary to make a single-cell frame according to the circulation conditions, which is costly to disassemble the single-cell stack, to process the single-cell frame, to reassemble the single-cell stack, and to achieve the completed single-cell frame. In the case of a desired differential pressure state, further decomposition/processing/assembly is required.

<Embodiment 2>

In the second embodiment, in the case of the RF battery 1 shown in Fig. 1, when the positive electrode electrolyte and the negative electrode electrolyte are circulated in the cell stack 2, the circulation of both electrolyte solutions is maintained. The second differential pressure state in which the pressure of the negative electrode electrolyte of the separator 101 is higher than the pressure of the positive electrode electrolyte (the state in which the pressure acts on the direction of the white arrow in the unit cell 100 of FIG. 1 with respect to the separator 101).

In the second differential pressure state, the flow rate control unit 5 causes the liquid supply amount of the negative electrode electrolyte from the pump 113 of the negative electrode circulation mechanism 3N to be supplied from the positive electrode electrolyte of the pump 112 of the positive electrode circulation mechanism 3P. The amount is large and thus made.

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 the two electrolytes is stopped. The two representative control modes will be described with reference to Figs. 8 and 9 . The views of Figs. 8 and 9 are as shown in Figs. 2 and 3 of the first embodiment.

[Control Mode III]

As shown in the graph of Fig. 8, in the control mode III, the two electrolyte solutions are circulated at a time t0 from a state in which the liquid supply amount of the negative electrode electrolyte solution is larger than the liquid amount of the positive electrode electrolyte solution to circulate the two electrolyte solutions. Start to stop. In this case, the rate of decrease in the amount of liquid to be supplied (the amount of circulation) of the negative electrode electrolyte is made larger than the rate of decrease in the amount of liquid to be supplied (the amount of circulation of the positive electrode electrolyte). And at the moment T1 causes the liquid feeding of the two electrolytes to stop almost simultaneously.

According to the above control mode III, the difference in the amount of liquid supply (circulation amount) between the two electrolytes can be gradually reduced while the circulation of the two electrolytes is stopped. As a result, the stress acting on the separator 101 (refer to FIG. 1) can be gradually reduced during the period in which the circulation of the two electrolyte solutions is stopped, so that the damage of the separator 101 can be effectively prevented.

[Control Mode IV]

As shown in the graph of Fig. 9, in the control mode IV, the cycle of the two electrolytes is also stopped at time t0. In the control mode IV, the rate of decrease in the amount of liquid to be supplied (the amount of circulation) of the positive electrode electrolyte is the same as the rate of decrease in the amount of liquid to be supplied (the amount of circulation of the negative electrode electrolyte). Originally, the liquid supply amount of the positive electrode electrolyte solution is smaller than the liquid supply amount of the negative electrode electrolyte solution. Therefore, when the rate of decrease in the liquid supply amount of the two electrolyte solutions is the same, the liquid supply of the positive electrode electrolyte is stopped at time t2, and thereafter, At time t3, the liquid supply of the negative electrode electrolyte is stopped. In other words, after the circulation of the positive electrode electrolyte is stopped, the negative electrode electrolyte is still circulated in the cell stack 2 (see FIG. 1), so that the second differential pressure state can be surely maintained until the cycle of stopping the two electrolytes.

Further, each of the positive electrode piping and the negative electrode piping of the RF battery 1 shown in Fig. 1 has a plurality of valves. In Fig. 1, valves 114 and 116 are present in the positive electrode line, and valves 115 and 117 are present in the negative electrode line. The flow rate control unit 5 may control the opening/opening and closing times of the valves 114 to 117. By adopting this method, it is easy to carry out the above two control modes.

"Related composition when the cycle stops"

It is preferable to maintain the second differential pressure state in which the pressure of the negative electrode electrolyte acting on the separator 101 is higher than the pressure of the positive electrode electrolyte after the circulation of the two electrolytes is stopped by the control of the flow rate control unit 5 of Fig. 1 . The reason is that, as long as the two electrolytes are not circulated, the differential pressure state is maintained, and when the circulation of the two electrolytes is restarted, even if the pump 113 that circulates the negative electrode electrolyte is started for some reason, the pump is circulated for the positive electrode electrolyte. The startup of the pump 112 is still late, and it is still difficult to change the pressure of the positive electrode electrolyte acting on the separator 101 to a higher differential pressure than the pressure of the negative electrode electrolyte.

In the case where the circulation of the two electrolytes is maintained in the second differential pressure state, the negative electrode tank 107 is disposed at a position higher than the positive electrode tank 106. Further, after the circulation of the two electrolytes is stopped, the two electrolytes are filled in the cell stack 2. By adopting this method, even if the two electrolytes are not circulated, the second differential pressure state can be maintained by the borrowing amount.

"Composition to make the formation of the second differential pressure state easier"

In addition to the difference in the amount of liquid supplied from the pumps 112 and 113, a second differential pressure forming mechanism for facilitating the formation of the second differential pressure state may be provided in the RF battery 1. The second differential pressure forming mechanism is formed by changing the configuration (mainly size) of the existing member material included in the RF battery 1. Specifically, the difference between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N is set to form a difference. . Hereinafter, an embodiment of the second differential pressure forming mechanism will be described with reference to Figs. 10 to 13 . In Figures 10 to 12, the grooves, pumps, and The valve, further connected to the single cell stack in Fig. 13, is also omitted.

[Formation of differential pressure state due to the difference in length between the positive electrode tube and the negative electrode tube]

FIG. 10 shows a differential pressure forming mechanism 6E formed by making the negative electrode returning tube 111 longer than the positive electrode returning pipe 110. When the tube is grown, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 10, since the negative electrode return pipe 111 is longer than the positive electrode return pipe 110, the pressure loss of the negative electrode return pipe 111 is larger than the positive pressure return pipe 110. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 is higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the positive electrode electrolyte. Two differential pressure states.

Although not shown, the positive electrode use pipe 108 may be longer than the negative electrode use pipe 109 to form the differential pressure forming mechanism 6E. In this case, the state is established in which the pressure of the positive electrode electrolyte in the cell stack 2 is lowered, and the pressure of the upper electrode electrolyte solution is higher than the pressure of the positive electrode electrolyte solution. Needless to say, the differential pressure forming mechanism 6A may be formed by combining the configurations in which the lengths of the return pipes 110 and 111 are different and the configurations in which the lengths of the outward pipes 108 and 109 are different.

[Formation of differential pressure state due to the difference in thickness between the positive electrode tube and the negative electrode tube]

FIG. 11 shows the return path of the negative electrode returning tube 111 to the positive electrode. The differential pressure forming mechanism 6F is formed by the tube 110 being thin. When the tube is refined, 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 110 is larger than the positive pressure return pipe 111. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 is higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the positive electrode electrolyte. Two differential pressure states. When the differential pressure forming mechanism 6F is used, it is preferable that the inner diameter of the negative electrode returning pipe 111 is 80% or less of the inner diameter of the positive electrode returning pipe 110.

Although not shown, the positive electrode use pipe 108 may be thinner than the negative electrode use pipe 109 to form the differential pressure forming mechanism 6F. In this case, the state is established in which the pressure of the positive electrode electrolyte in the cell stack 2 is lowered, and the pressure of the upper electrode electrolyte solution is higher than the pressure of the positive electrode electrolyte solution. Needless to say, the differential pressure forming mechanism 6F may be formed by combining the configurations in which the thicknesses of the return pipes 110 and 111 are different and the configurations in which the thicknesses of the outward pipes 108 and 109 are different.

[Formation of differential pressure state due to the difference in the path between the positive electrode tube and the negative electrode tube]

FIG. 12 shows a differential pressure forming mechanism 6G formed by bending the negative electrode returning tube 111 more than the positive electrode returning pipe 110. When the bending of the tube is excessive, the pressure loss of the electrolyte flowing in the tube increases. In the case of FIG. 12, the negative electrode return pipe 111 is made to be larger than the positive electrode return pipe 110. Since the bending is complicated, 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 is higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than the pressure of the positive electrode electrolyte. Two differential pressure states. In addition, in addition to increasing the bend of the tube, for example, by narrowing the bending radius of the bend of the tube, the tube can be complicatedly bent.

Although not shown, the positive electrode use pipe 108 may be more complicatedly bent than the negative electrode use pipe 109 to form the differential pressure forming mechanism 6G. Needless to say, the differential pressure forming mechanism 6G may be formed by combining the configurations in which the bending states of the return pipes 110 and 111 are different and the configurations in which the bending states of the outward pipes 108 and 109 are different.

[Formation of differential pressure state due to the difference in opening degree of the valve for the positive electrode and the valve for the negative electrode]

Each of the positive electrode conduit and the negative electrode conduit of the RF battery 1 shown in Fig. 1 has a plurality of valves. The valves 114 to 117 are used to stop the circulation of the electrolytic solution to the cell stack 2, and the like. The differential pressure forming mechanism can also be formed by using these valves 114 to 117. For example, the valve 117 of the negative electrode return pipe 111 is compressed (reduced opening degree) than the valve 116 of the positive electrode return pipe 110, so that the pressure loss of the negative electrode return pipe 111 can be made larger than that of the positive electrode return pipe 110. The pressure loss is large. As a result, the pressure of the negative electrode electrolyte in the cell stack 2 is higher than the pressure of the positive electrode electrolyte, and the pressure of the negative electrode electrolyte acting on the separator 101 in the cell stack 2 can be made higher than that of the positive electrode electrolyte. A second differential pressure state with a high pressure.

Further, the positions of the valves 114 to 117 are not limited to the positions shown in Fig. 1 . In addition, in FIG. 1, although there are two valves in each of the positive electrode line and the negative electrode line, the number of valves is not limited to this. For example, each of the positive electrode conduit and the negative electrode conduit may have three or more valves, or one valve may be provided.

When the valve 114 of the positive electrode bypass pipe 108 is compressed than the valve 115 of the negative electrode bypass pipe 109, the pressure of the positive electrode electrolyte in the cell stack 2 can be lowered to make the above-described differential pressure state. Needless to say, the difference in the opening degrees of the valves 116 and 117 of the return pipes 110 and 111 and the different degrees of opening of the valves 114 and 115 of the outward pipes 108 and 109 may be combined to form a differential pressure forming mechanism.

[Formation of a differential pressure state due to a difference in the configuration of the positive electrode heat exchanger and the negative electrode 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 the heat exchangers 4P and 4N.

The upper part of FIG. 13 is a schematic configuration diagram of the negative electrode heat exchanger 4N, and the lower part of FIG. 13 is a schematic configuration view of the positive electrode heat exchanger 4P. The basic configuration of the heat exchanger is known, for example, from Japanese Patent Laid-Open Publication No. 2013-206566. For example, as shown in Fig. 13, the piping 42P (42N) can be climbed to the accumulated refrigerant 40P (40N). The inside of the container 41P (41N) constitutes the heat exchanger 4P (4N). Since the piping 42P (42N) is connected to the return pipe 110 (111), the positive electrode electrolyte (negative electrode electrolyte) flows through the inside. 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) is a liquid 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 piping 42N of the negative electrode heat exchanger 4N may be longer than the piping 42P of the positive electrode heat exchanger 4P as shown in the drawing. By this means, the pressure of the negative electrode electrolyte acting on the diaphragm 101 can be made higher than the pressure of the positive electrode electrolyte for the same reason as the differential pressure forming mechanism 6A which changes the length of the return pipes 110 and 111. Pressure state.

Further, the pipe 42N is made thinner than the pipe 42P, or the bending portion of the pipe 42N is larger than the bending portion of the pipe 42P, so that the above-described differential pressure state can be made. Of course, the differential pressure state may be made by combining the length of the pipe, the thickness of the pipe, and the bending state of the pipe. Further, only the negative electrode heat exchanger 4N is provided, and the positive electrode heat exchanger 4P is not provided, so that the above-described differential pressure state can be made.

[other policy]

The negative electrode groove 107 of FIG. 1 may be disposed higher than the positive electrode groove 106 to form the above-described differential pressure state. In addition, the anode can also be used in the return tube 111 position. The differential pressure state is formed at a position where the positive electrode return pipe 110 is high.

[about combination]

Each of the differential pressure forming mechanisms described above may be used singly or in combination. For example, when the configuration in which the lengths of the positive electrode tubes and the negative electrode tubes are different, and the configuration in which the positive electrode tubes and the negative electrode tubes are different in thickness are combined, it is easy to form a desired differential pressure state.

Further, the second differential pressure state is preferably a differential pressure state in which the pressure of the negative electrode electrolyte acting on the separator 101 is higher than the pressure of the positive electrode electrolyte over the entire surface of the separator 101. The reason for this is that 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 partially acting on the separator on the surface of the separator is higher than that of the positive electrode. The pressure of the electrolyte is small. According to the differential pressure forming mechanism described above, the differential pressure state in which the pressure of the negative electrode electrolyte acting on the separator 101 is higher than the pressure of the positive electrode electrolyte can be made over the entire surface of the separator 101.

[Effect of the second differential pressure forming mechanism]

In the above-described embodiment, the flow path of the positive electrode electrolyte in the cell stack 2 is the same as that of the negative electrode electrolyte, and the difference between the positive electrode circulation mechanism 3P and the negative electrode circulation mechanism 3N is set. A desired differential pressure state is formed. Therefore, with the second differential pressure forming mechanism described above, it is possible to easily form a desired differential pressure state without decomposing the cell stack 2. A redox flow battery such as Patent Document 1 is made in a single cell stack When the flow path of the positive electrode electrolyte of the cell frame is different from the flow path of the negative electrode electrolyte, when the flow conditions of the electrolyte such as the type of the electrolyte are changed, it is difficult to make a desired change depending on the flow conditions. The differential pressure state. The reason is that it is necessary to make a single-cell frame according to the circulation conditions, which is costly to disassemble the single-cell stack, to process the single-cell frame, to reassemble the single-cell stack, and to achieve the completed single-cell frame. In the case of a desired differential pressure state, further decomposition/processing/assembly is required.

[Industrial Applicability]

The redox flow battery and the redox flow battery operating method of the present invention can be used for power generation of new energy sources such as solar power generation and wind power generation, and can be used for stabilizing the fluctuation of power generation output and power storage for remaining power generation power. In addition to load leveling, it can be installed in a general power plant at the same time, and it can be used for measures such as instantaneous voltage drop, power failure countermeasures, and load leveling.

Claims (5)

A method for operating a redox flow battery in which a plurality of cells having a positive electrode, a negative electrode, and a separator are laminated, and a positive electrode is circulated by using a circulation mechanism for a positive electrode, and a circulation mechanism for a negative electrode is used. When the negative electrode electrolyte is circulated, and the positive electrode electrolyte and the negative electrode electrolyte are circulated in the cell stack, the circulation amount of one electrolyte solution is larger than the circulation amount of the other electrolyte solution, and the action is made to the above. The pressure of the one of the electrolytes of the separator is higher than the pressure of the other electrolyte solution acting on the separator, and the circulation amount of the positive electrode electrolyte and the negative electrode electrolyte is reduced to circulate the two electrolytes. At the time of the stop, the circulation amount of the one of the electrolytic solutions is made larger than the circulation amount of the other electrolytic solution, and the differential pressure state is maintained. The method for operating a redox flow battery according to the first aspect of the invention, wherein, when the circulation of the positive electrode electrolyte and the negative electrode electrolyte is stopped, a rate of decrease in a circulation amount of the one electrolyte solution is higher than the other one The circulation amount of the electrolyte is reduced at a high rate, and the circulation of the two electrolytes is simultaneously stopped. The method for operating a redox flow battery according to the first aspect of the invention, wherein, when the circulation of the positive electrode electrolyte and the negative electrode electrolyte is stopped, a rate of decrease in a circulation amount of the one electrolyte solution is different from the other side The rate of decrease in the circulation amount of the electrolyte is adjusted, The circulation of the one electrolytic solution is stopped later than the circulation of the other electrolytic solution. The method of operating a redox flow battery according to any one of the first to third aspects of the present invention, wherein the tank of the electrolytic solution provided in the circulation mechanism for circulating the one of the electrolyte solutions is disposed in a ratio of the other side The circulation mechanism of the electrolyte circulation has a position of a groove height of the electrolyte, and when the two electrolytes are not circulated, the two cell stacks are kept filled with the two electrolytes. A redox flow battery comprising: a single cell stack in which a plurality of cells having a positive electrode, a negative electrode, and a separator are laminated; a circulation mechanism for circulating a positive electrode electrolyte in the cell stack; and a circulation mechanism for a negative electrode that circulates a negative electrode electrolyte; the redox flow battery system includes a flow rate control unit that is a period from when the positive electrode electrolyte solution and the negative electrode electrolyte solution are circulated to a stop state The positive electrode circulation mechanism and the negative electrode circulation mechanism are controlled so that the circulation amount of one of the electrolytic solutions is larger than the circulation amount of the other electrolytic solution.