JP2013037856A - Redox flow cell - Google Patents

Abstract

A redox flow battery capable of efficiently removing impurities from an electrolytic solution is provided.
An RF battery (1A) includes a battery cell (100c) having a positive electrode cell (102) containing a positive electrode, a negative electrode cell (103) containing a negative electrode, and a diaphragm (101) interposed between the polar cells (102, 103). In addition, the positive electrode electrolyte and the negative electrode electrolyte are supplied to the electrode cells 102 and 103 to perform charge / discharge. 1 A of RF batteries are equipped with the cell 10 for a filter which filters each electrode electrolyte solution. The filter cell 10 has a structure similar to that of the battery cell 100c, and includes a positive electrode filter cell 12 including a positive electrode electrolyte filter for filtering the positive electrode electrolyte, and a negative electrode electrolyte filter for filtering the negative electrode electrolyte. Negative electrode filter cell 13, and separator 11 that partitions each electrode filter cell 12, 13. The filter for the positive electrode electrolyte and the filter for the negative electrode electrolyte are more excellent in filtration characteristics for removing impurities of the electrolyte than the positive electrode and the negative electrode.
[Selection] Figure 1

Description

  The present invention relates to a redox flow battery. In particular, the present invention relates to a redox flow battery that can efficiently remove impurities in an electrolytic solution.

  In recent years, the introduction of wind power generation and solar power generation using renewable energy such as wind power and sunlight has been promoted worldwide as a countermeasure against global warming. Since these power generation outputs are affected by the weather, large-scale introduction of power generation using renewable energy causes a problem that it is difficult to maintain the frequency and voltage of the power system. As one of the countermeasures against this problem, it is expected to install a large-capacity storage battery to smooth the output fluctuation, save surplus power, and level the load.

  One of the large-capacity storage batteries is a redox flow battery (RF battery). An RF battery is a battery that charges and discharges using a difference in oxidation-reduction potential between ions contained in a positive electrode electrolyte and ions contained in a negative electrode electrolyte. As shown in the operational principle diagram of the RF battery in FIG. 7, the RF battery 100 includes a positive electrode cell 102 incorporating a positive electrode 104, a negative electrode cell 103 incorporating a negative electrode 105, and an ion permeable membrane. , 103 is provided with a battery cell 100c. The electrode electrodes 104 and 105 are typically made of carbon felt.

  Each electrode cell 102, 103 has a respective electrode electrolyte tank 106, 107 for storing each electrode electrolyte to be supplied to each electrode cell 102, 103, and each electrode cell 102 from each electrode electrolyte solution tank 106, 107. , 103, and return pipes 110, 111 for returning the respective electrolytes from the electrode cells 102, 103 to the respective electrolyte electrolyte tanks 106, 107. Connected through. The electrolyte stored in each of the electrode electrolyte tanks 106 and 107 is circulated to the electrode cells 102 and 103 by the pumps 112 and 113.

  For example, each electrode electrolyte used in the RF battery 100 is mixed with impurities such as dust during the assembly of the RF battery 100, or is repeatedly charged and discharged, so that the battery cell 100c, the circulation path 100p, 100n, or In some cases, constituent materials such as the respective electrolyte tanks 106 and 107 are gradually eluted and precipitated as impurities. When the RF battery 100 is operated (charged / discharged) using an electrolyte mixed with impurities, the impurities adhere to the electrode electrodes 104 and 105. As a result, the flow of the electrolytic solution is hindered and the pressure loss increases, or the internal resistance of the battery cell increases and the battery performance decreases.

  As a technique for solving this problem, Patent Literature 1 discloses that before the operation of the RF battery, impurities are removed by filtering each electrode electrolyte solution using a filter, or the battery cell of the RF battery in advance. It is described that impurities are removed by charging and discharging using a filtration cell having the same structure.

JP 2002-367657 A

  As described above, during the operation of the RF battery, there is a possibility that impurities are deposited as charge / discharge is repeated, resulting in a decrease in battery performance. Therefore, it is desired to remove impurities in the electrolytic solution not only before the operation of the RF battery but also during the operation of the RF battery. On the other hand, a specific configuration for efficiently removing impurities during operation of the RF battery, in particular, a specific configuration for removing impurities without hindering the operation of the RF battery has not been proposed.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a redox flow battery capable of efficiently removing impurities in an electrolytic solution.

  The redox flow battery of the present invention comprises a battery cell having a positive electrode cell incorporating a positive electrode, a negative electrode cell incorporating a negative electrode, and a diaphragm interposed between the positive electrode cell and the negative electrode cell. The electrolytic solution is supplied to each electrode cell to perform charging / discharging. The redox flow battery further includes each electrode electrolyte tank, each circulation path, a pump, and a filter cell. Each electrode electrolyte tank stores each electrode electrolyte supplied to each electrode cell. Each circulation path has an outward pipe that sends each electrode electrolyte from each electrode electrolyte tank to each electrode cell, and a return pipe that returns each electrode electrolyte from each electrode cell to each electrode electrolyte tank. A pump is provided in each circulation path, and circulates each electrode electrolyte. The filter cell is for filtering each electrolyte solution supplied to each electrode cell, and has the same structure as the battery cell. Specifically, a positive electrode filter cell, a negative electrode filter cell, and a separator are provided. The positive electrode filter cell incorporates a positive electrode electrolyte filter through which the positive electrode electrolyte flows and filters the positive electrode electrolyte. The negative electrode filter cell incorporates a negative electrode electrolyte filter through which the negative electrode electrolyte flows and filters the negative electrode electrolyte. The separator partitions the positive electrode filter cell and the negative electrode filter cell. And the filter for positive electrode electrolytes and the filter for negative electrode electrolytes are excellent in the filtration characteristic which removes an impurity rather than the positive electrode and negative electrode of a battery cell.

  According to the redox flow battery of the present invention, the filter cell for filtering each electrode electrolyte supplied to the battery cell is a filter for each electrode electrolyte having better filtering characteristics than removing each electrode of the battery cell. By providing, the impurities of each electrode electrolyte can be removed efficiently. Therefore, since it can suppress that an impurity adheres to each electrode electrode, a raise of internal resistance can be suppressed and in addition, since the flow of electrolyte solution is not inhibited, the increase in pressure loss can be suppressed. As a result, deterioration of battery characteristics can be suppressed. In addition, since the filter cell has a structure similar to that of the battery cell, it is possible to prevent leakage of the electrolytic solution.

  As one form of this invention redox flow battery, it is mentioned that the said cell for filters is provided in the middle of the said circulation path.

  According to said structure, each electrode electrolyte solution can be distribute | circulated to the cell for filters with the pump for distribute | circulating each electrode electrolyte solution to a battery cell. That is, since the pump can be shared by the battery cell and the filter cell, the configuration of the redox flow battery can be simplified.

  As one form of the redox flow battery of the present invention, the filter cell may be provided in the middle of the forward pipe in the circulation path.

  According to the above configuration, each electrode electrolyte supplied to the battery cell is filtered and removed from the impurities sent from each electrode electrolyte tank and circulated in the battery cell. Each electrolyte solution from which impurities are removed can always be circulated in the battery cell. Therefore, it can further suppress that an impurity adheres to each electrode.

  One embodiment of the redox flow battery of the present invention includes a detecting means for detecting the degree of clogging of each electrode electrolyte filter of the filter cell.

  According to said structure, the clogging degree of each electrode electrolyte filter can be grasped | ascertained, and the replacement time of a filter can be grasped | ascertained.

  As one form of the redox flow battery of the present invention, when the filter cell is provided in the middle of the circulation path, a bypass that bypasses the inflow side and the outflow side of each electrode electrolyte solution of the filter cell in the circulation path. And a three-way valve attached to a connection point between the bypass pipe and the circulation path.

  According to the above configuration, even when the filter cell is clogged and the supply amount of the electrolyte solution to the battery cell is reduced, the supply of each electrolyte solution to the battery cell by providing the bypass pipe The amount can be secured. In addition, by providing a three-way valve at the connection point between the bypass pipe and the circulation path, if it becomes necessary to replace each electrode electrolyte filter of the filter cell due to clogging of each electrode electrolyte filter, the battery Each electrode electrolyte filter can be replaced without stopping the charging / discharging (operation) of the cell.

  Since the redox flow battery of the present invention can efficiently remove impurities in each electrode electrolyte, it is possible to suppress an increase in internal resistance of the battery cell and to suppress a decrease in battery efficiency.

1 is a schematic configuration diagram of a redox flow battery according to Embodiment 1. FIG. 3 is a schematic configuration diagram of a redox flow battery according to Embodiment 2. FIG. 6 is a schematic configuration diagram of a redox flow battery according to Embodiment 3. FIG. 6 is a schematic configuration diagram of a redox flow battery according to Embodiment 4. FIG. 6 is a schematic configuration diagram of a redox flow battery according to Embodiment 5. FIG. 10 is a schematic configuration diagram of a redox flow battery according to Embodiment 6. FIG. It is an operation | movement principle figure of a redox flow battery. It is a schematic block diagram of a cell stack. In a test example, it is a graph which shows the relationship between the continuous operation days of a redox flow battery, and an internal resistivity, Comprising: (A) shows the case of the redox flow battery which concerns on Embodiment 3, (B) is the conventional redox flow. The case of a battery is shown.

  Hereinafter, embodiments of the redox flow battery of the present invention will be described with reference to the drawings. The basic configuration of the redox flow battery of the present invention is the same as that of a conventional redox flow battery. Therefore, first, the basic configuration of the redox flow battery will be described. Thereafter, the unique configuration of each embodiment will be described with reference to the drawings.

《Common structure of redox flow battery》
[overall structure]
FIG. 7 is an operation principle diagram showing a part having a common configuration in the RF battery of each embodiment. The RF battery 100 of FIG. 7 typically includes electric power including a power generation unit (for example, a solar power generator, a wind power generator, other general power plants, etc.) and a substation facility via an AC / DC converter. It is connected to the grid, is charged using the power generation unit as a power supply source, and is discharged using the load as a power supply target. Similar to the conventional RF battery, the RF battery 100 includes a battery cell 100c and a circulation mechanism (tank, piping, pump) that circulates the electrolyte in the battery cell 100c.

[Battery cells and circulation mechanism]
The battery cell 100c included in the RF battery 100 includes a positive electrode cell 102 including a positive electrode 104, a negative electrode cell 103 including a negative electrode 105, a diaphragm 101 that partitions each of the electrode cells 102 and 103 and transmits ions, With Typically, each electrode is made of carbon felt, and the diaphragm is an ion exchange membrane such as a cation exchange membrane or an anion exchange membrane.

  In the positive electrode cell 102, a positive electrode electrolyte solution tank 106 for storing a positive electrode electrolyte solution supplied to the positive electrode cell 102, an outward piping 108 for sending the positive electrode electrolyte solution from the positive electrode electrolyte solution tank 106 to the positive electrode cell 102, and the positive electrode cell 102. To the positive electrode electrolyte tank 106 via a circulation path 100p having a return pipe 110 for returning the positive electrode electrolyte. Similarly, in the negative electrode cell 103, a negative electrode electrolyte solution tank 107 for storing a negative electrode electrolyte solution supplied to the negative electrode cell 103, an outward piping 109 for sending the negative electrode electrolyte solution from the negative electrode electrolyte solution tank 107 to the negative electrode cell 103, The negative electrode cell 103 is connected to the negative electrode electrolyte solution tank 107 via a circulation path 100n having a return pipe 111 for returning the negative electrode electrolyte. The forward pipes 108 and 109 are provided with pumps 112 and 113 for circulating the respective electrolyte solutions. The battery cell 100c uses the circulation paths 100p and 100n and the pumps 112 and 113, and positive electrode electrolysis of the positive electrode electrolyte tank 106 to the positive electrode cell 102 (positive electrode 104) and the negative electrode cell 103 (negative electrode 105), respectively. The negative electrode electrolyte solution in the negative electrode electrolyte solution tank 107 is circulated and charged and discharged along with the valence change reaction of the active material ions that become the active material in the electrolyte solution of each electrode. In the RF battery 100 shown in FIG. 7, the case where vanadium ion aqueous solution is used for each electrode electrolyte solution is mentioned as an example. Moreover, the solid line arrow in the battery cell 100c in FIG. 7 shows a charging reaction, and the broken line arrow shows a discharging reaction.

  The battery cell 100c is normally used in a form called a cell stack 200 in which a plurality of battery cells are stacked as shown in FIG. Each of the electrode cells 102 and 103 constituting the battery cell 100c includes a bipolar plate 211 in which the positive electrode 104 is disposed on one surface and the negative electrode 105 is disposed on the other surface, liquid supply holes 213 and 214 for supplying an electrolytic solution, and an electrolytic solution. A configuration using a cell frame 210 having drainage holes 215 and 216 for discharging and having a frame body 212 formed on the outer periphery of the bipolar plate 211 is typical. By laminating a plurality of cell frames 210, the liquid supply holes 213 and 214 and the drainage holes 215 and 216 constitute a flow path for the electrolytic solution, and the flow paths are connected to the tubes 108 to 111. The cell stack 200 is configured by repeatedly stacking a cell frame 210, a positive electrode 104, a diaphragm 101, a negative electrode 105, a cell frame 210,. Typically, the bipolar plate is made of plastic carbon, and the cell frame is made of a resin such as vinyl chloride. A pair of end plates 220 are arranged on both sides, and both end plates 220 are tightened with a tightening member 230 such as a bolt.

[Electrolyte]
The positive electrode electrolyte and the negative electrode electrolyte used for the RF battery 100 may be any of the following (1) to (5).
(1) The positive electrode electrolyte contains manganese ions, and the negative electrode electrolyte contains at least one metal ion selected from titanium ions, vanadium ions, chromium ions, zinc ions, and tin ions.
(2) The positive electrode electrolyte contains both manganese ions and titanium ions, and the negative electrode electrolyte contains at least one metal ion selected from titanium ions, vanadium ions, chromium ions, zinc ions, and tin ions. contains.
(3) The electrolyte solution for positive electrodes and the electrolyte solution for negative electrodes contain both manganese ions and titanium ions.
(4) The electrolyte solution for positive electrodes and the electrolyte solution for negative electrodes contain vanadium ion.
(5) The positive electrode electrolyte contains iron ions, and the negative electrode electrolyte contains at least one metal ion selected from titanium ions, vanadium ions, chromium ions, zinc ions, and tin ions.

  By doing so, a preferable RF battery 100 can be configured. In particular, as the electrolytic solutions (1) and (2), high electromotive force can be obtained by using manganese ions as the positive electrode active material and titanium ions or vanadium ions listed above as the negative electrode active material. A high electromotive force can be obtained by using manganese ions for the positive electrode active material and titanium ions for the negative electrode active material as the electrolytic solution (3). Furthermore, in the electrolytes (2) and (3) above, the positive electrode active material is manganese ions, and by separately containing titanium ions, high electromotive force can be obtained, and precipitates that increase battery resistance can be generated. Can be effectively suppressed. As said electrolyte solution (5), the structure in which a positive electrode electrolyte solution contains an iron ion and a negative electrode electrolyte solution contains a chromium ion is suitable.

Solvents for the electrolyte include H ₂ SO ₄ , K ₂ SO ₄ , Na ₂ SO ₄ , H ₃ PO ₄ , H ₄ P ₂ O ₇ , K ₂ PO ₄ , Na ₃ PO ₄ , K ₃ PO ₄ , HNO ₃ , at least one aqueous solution selected from KNO ₃ and NaNO ₃ can be used.

Embodiment 1
In the first embodiment, as shown in FIG. 1, the RF battery 1 </ b> A further includes a filter cell 10 that filters each electrode electrolyte to remove impurities in the electrolyte, in addition to the basic configuration described above. The feature of the present invention lies in the structure of the filter cell 10 for filtering each electrode electrolyte. Hereinafter, this feature point will be mainly described. Here, the case where the circulation path of each electrode electrolyte in the filter cell 10 and the circulation path of each electrode electrolyte in the battery cell 100c are different paths will be described as an example.

[Filter cell and circulation mechanism]
The basic configuration of the filter cell 10 is the same as that of the battery cell 100c. As shown in FIG. 1, the positive electrode filter cell 12 in which the positive electrode electrolyte is circulated and the negative electrode filter in which the negative electrode electrolyte is circulated. The cell 13 and the separator 11 which divides each pole filter cell are provided. The positive electrode filter cell 12 includes a positive electrode electrolyte filter 14 for filtering the positive electrode electrolyte shown in FIG. 8, and the negative electrode filter cell 13 includes a negative electrode electrolyte filter 15 for filtering the negative electrode electrolyte. The However, the characteristics of the electrode electrolyte filters 14 and 15 are different from those of the electrode electrodes 104 and 105.

  The constituent materials and structures of the positive electrode electrolyte filter 14 and the negative electrode electrolyte filter 15 are those that have better filtering characteristics than the positive electrode 104 and the negative electrode 105, respectively. The constituent material of each of the electrode electrolyte filters 14 and 15 is made of a material suitable for charging and discharging, such as the electrode electrodes 104 and 105 incorporated in the electrode cells 102 and 103, regardless of conductivity. They may not be formed, and may be made of a material having a lower conductivity than the electrode electrodes 104 and 105, or an insulating material. For example, polypropylene (PP), carbon, etc. are mentioned. Further, as the structure of each electrode electrolyte filter 14, 15, each electrode electrolyte filter 14, 15 removes impurities mixed or precipitated in each electrode electrolyte than each electrode 104, 105. Anything is possible. For example, those having a structure that allows the electrolyte to pass more easily than the electrode electrodes 104 and 105, those having a structure that does not allow impurities to pass through, and those that easily adhere to impurities can be cited. Specifically, a mesh or a felt having a pore diameter of 100 μm or less, or at least one of surface areas more than twice the surface area of each of the electrode electrodes 104 and 105 can be used. In particular, the pore diameter is preferably 10 μm or less, and the surface area is preferably 5 times or more, more preferably 10 times or more.

  The separator 11 only needs to be made of a material in which the electrolyte solution of each electrode of the positive electrode filter cell 12 and the negative electrode filter cell 13 is not mixed. For example, a plastic sheet may be used, and the same ion exchange membrane as the diaphragm 101 included in the battery cell 100c may be used.

  Similarly to the battery cell 100c, the filter cell 10 can be used as a stacked form (cell stack 20) as shown in FIG. Each of the electrode filter cells 12 and 13 constituting the filter cell 10 has a positive electrode electrolyte filter 14 on one surface and a negative electrode electrolyte filter 15 on the other surface, similarly to the electrode cells 102 and 103 of the battery cell 100c. A bipolar plate 211, a supply hole 213, 214 for supplying an electrolytic solution, and a drainage hole 215, 216 for discharging the electrolytic solution, and a frame 212 formed on the outer periphery of the bipolar plate 211. A configuration using a cell frame 210 is available. By laminating a plurality of cell frames 210, the liquid supply holes 213 and 214 and the drain holes 215 and 216 constitute a flow path for the electrolyte. The cell stack 20 is configured by repeatedly laminating a cell frame 210, a positive electrode electrolyte filter 14, a separator 11, a negative electrode electrolyte filter 15, a cell frame 210,. As the constituent materials of the bipolar plate 211 and the frame 212 of the cell frame 210, the same materials as described above are used. Then, like the cell stack 200, a pair of end plates 220 are arranged on both sides, and both end plates 220 are tightened with a tightening member 230 such as a bolt.

  In the positive electrode filter cell 12, an electrolyte common to the positive electrode electrolyte supplied to the positive electrode cell 102 of the battery cell 100c is circulated. Similarly, in the negative electrode filter cell 13, an electric liquid common to the negative electrode electrolyte supplied to the negative electrode cell 103 of the battery cell 100c is circulated. That is, the positive electrode filter cell 12 and the negative electrode filter cell 13 of the filter cell 10 are respectively supplied with the electrolyte from the positive electrode electrolyte tank 106 and the negative electrode electrolyte tank 107.

  In this example, the battery cell 100c has a different circulation path. Specifically, in the positive electrode filter cell 12, the positive electrode electrolyte tank 106 includes a forward pipe 31 and a return pipe 33, which are different from the forward pipe 108 and the return pipe 110 connected to the positive electrode cell 102. 30p is connected. On the other hand, in the negative electrode filter cell 13, a negative electrode electrolyte solution tank 107 is connected via a circulation path 30 n having an outgoing pipe 32 and a return pipe 34, which are different from the outgoing pipe 109 and the return pipe 111 connected to the negative electrode cell 103. Connected. Each forward passage pipe 31, 32 includes a pump 35, 36 that circulates each electrolyte solution through the filter cell 10. The filter cell 10 uses the circulation paths 30p and 30n and the pumps 35 and 36 to supply the electrolyte solution common to the electrode electrolyte solution supplied to the battery cell 100c to the electrode electrolyte tanks 106 and 107, respectively. The electrolyte solution is circulated to the electrode filter cells 12 and 13 and filtered to remove impurities mixed in the electrolyte solution. The filtered electrode electrolytes are returned to the electrode electrolyte tanks 106 and 107, respectively.

  According to the configuration of the first embodiment described above, the battery cell 100c is provided with the filter cell 10 including the respective electrode electrolyte filters 14 and 15 having better filtration characteristics than the electrode electrodes 104 and 105. Impurities mixed or deposited in each electrode electrolyte supplied can be efficiently removed, so that the impurities can be prevented from adhering to the electrode electrodes 104 and 105 built in the electrode cells 102 and 103. Further, since each electrode electrolyte is filtered with a circulation path different from that of the battery cell 100c, each electrode electrolyte filter 14 of the filter cell 10 without stopping charging / discharging (operation) of the battery cell 100c, 15 can be exchanged. Since the filter cell 10 has the same structure as the battery cell 100c, leakage of the electrolyte can be prevented. In addition, since the battery cell 100c is made of a common member (for example, a cell frame or a diaphragm), the cost can be reduced.

<< Embodiment 2 >>
The RF battery 1B according to the second embodiment shown in FIG. 2 includes the above-described basic configuration and the filter cell 10 as in the first embodiment. However, the place where the filter cell 10 is provided is different from the first embodiment. Here, the circulation path of each electrode electrolyte in the filter cell 10 and the circulation path of each electrode electrolyte in the battery cell 100c follow the same path. That is, in the RF battery 1B, the filter cell 10 is provided in the middle of each electrode electrolyte circulation path of the battery cell 100c. More specifically, it is provided in the middle of the return pipes 110 and 111 for returning the electrode electrolytes from the battery cell 100 c to the electrode electrolyte tanks 106 and 107. Here, each of the electrode electrolyte solution tanks 106 and 107 is sent using the circulation paths 100p and 100n used to circulate each electrode electrolyte solution to the battery cell 100c and the pumps 112 and 113. The electrode electrolytes that have passed through the battery cell 100c are passed through the electrode filter cells 12 and 13 of the filter cell 10 to filter the electrode electrolytes and remove impurities. Then, each electrode electrolyte from which impurities have been removed is returned to each electrode electrolyte tank 106, 107.

  According to this configuration, the battery cell 100c and the filter cell 10 have a common circulation path for the electrode electrolytes. Therefore, the pump cells 112 and 113 that circulate the electrode electrolytes in the battery cell 100c are used for the filter cell 10. Each electrode electrolyte can be circulated. That is, the pumps 112 and 113 can be shared by the battery cell 100 c and the filter cell 10. Therefore, the configuration of the RF battery 1B that can remove impurities from each electrolyte solution can be simplified.

<< Embodiment 3 >>
The basic configuration of the RF battery 1C of the third embodiment shown in FIG. 3 is the same as that of the second embodiment, but the point where the filter cell 10 is provided is different from the second embodiment. Specifically, the RF battery 1C of the present example is provided in the middle of the forward pipes 108 and 109 for sending the electrolyte solution of each electrode from the electrode electrolyte tanks 106 and 107 to the electrode cells 102 and 103 (battery cell 100c). A filter cell 10 is provided. In other words, the filter cell 10 uses the tubes 108 to 111 and the pumps 112 and 113 that are used to circulate the electrode electrolytes to the battery cell 100 c, and the electrode electrolyte tanks 106 and 107. Then, each electrode electrolyte is passed through each electrode filter cell 12, 13 to filter each electrode electrolyte to remove impurities. And each electrode electrolyte from which the impurity was removed is continuously supplied to each cell 102, 103 of the battery cell 100c, and charging / discharging is performed. After that, it is returned to each of the electrode electrolyte tanks 106 and 107.

  According to this configuration, each electrode electrolyte supplied to the battery cell 100c is filtered while being sent from each electrode electrolyte solution tank 106, 107 and circulated in the battery cell 100c. In each cell 100c, each electrolyte solution from which impurities are removed can be circulated. Therefore, it is possible to further suppress the adhesion of impurities to the electrode electrodes 104 and 105.

<< Embodiment 4 >>
The RF battery 1D of the fourth embodiment shown in FIG. 4 is configured as a combination of the second and third embodiments. That is, the RF battery 1 </ b> D includes the filter cell 10 in the middle of the outgoing pipes 108 and 109 and in the middle of the backward pipes 110 and 111. Here, one filter cell 10 is provided for each of the two.

  According to this configuration, by providing the filter cell 10 in each of the forward pipes 108 and 109 and the return pipes 110 and 111, even if one of the filter cells 10 fails, the other filter cell 10 can be electrolyzed. Liquid impurities can be removed.

<< Embodiment 5 >>
The RF battery 1E according to the fifth embodiment shown in FIG. 5 further includes detection means for detecting the degree of clogging of the filter cell 10 with respect to the RF battery 1C according to the third embodiment. That is, the filter cell 10 is provided in the middle of the outgoing pipes 108 and 109.

  As a detection means provided in the RF battery 1E, the flow rate sensors 41 and 42 (flowmeters) for detecting the flow rate of the electrolyte flowing through the filter cell 10 or the pressure of the electrolyte that changes with the flow rate change For example, a pressure sensor (pressure gauge) or the like may be used. By using this detection means, it is possible to grasp the replacement timing of the electrode electrolyte solutions 14 and 15 of the filter cell 10.

  Specifically, the pump output and flow rate in each of the electrode electrolyte filters 14 and 15 that are not clogged, or the correlation data between the pump output and pressure is obtained in advance, and the detection result by the detection means is the result. If there is a certain deviation from the correlation data, it is determined that each of the electrode electrolyte filters 14 and 15 is clogged, and each of the electrode electrolyte filters 14 and 15 may be replaced. Particularly, in the RF battery 1E, the storage means for storing the correlation data as a table in the memory and the correlation data are called from the storage means, and each of the electrode electrolyte filters 14 and 15 is clogged compared with the detection result. It is preferable to provide a processing device including determination means for determining whether or not the In addition, it is better to provide confirmation means such as a display device such as a monitor for notifying the operator of the determination result. By doing so, it is possible to easily grasp the replacement time of each of the electrode electrolyte solutions 14 and 15 from the comparison between the detection result of the detection means and the correlation data.

  Here, the flow sensors 41 and 42 are provided on the inflow side of each electrolyte solution of the filter cell 10 in each of the forward passage pipes 108 and 109. Commercially available sensors can be used for the flow sensors 41 and 42.

  According to this configuration, in addition to the effects of the third embodiment, the degree of clogging of the filter cell 10 can be grasped from the detection result of the flow rate sensor. Therefore, the replacement timing of the electrode electrolyte filters 14 and 15 of the filter cell 10 can be determined. I can grasp.

Embodiment 6
The RF battery 1F according to the sixth embodiment shown in FIG. 6 further bypasses the inflow side and the outflow side of each electrode electrolyte of the filter cell 10 in the forward passage pipes 108 and 109 with respect to the RF battery 1E according to the fifth embodiment. It includes bypass pipes 51 and 52, and three-way valves 61 to 64 that are attached to connection points between the forward pipes 108 and 109 and the bypass pipes 51 and 52. That is, the filter cell 10 is provided in the middle of the outward pipes 108 and 109, and the detection means (flow rate sensors 41 and 42) for detecting the clogging of the filter cell 10 is connected to the filter cell 10 in the forward pipes 108 and 109. 10 are provided on the inflow side of each electrolyte solution.

  One ends of the bypass pipes 51 and 52 are connected between the flow rate sensors 41 and 42 and the inflow side of the filter cell 10 in the forward pipes 108 and 109. On the other hand, the other ends of the bypass pipes 51 and 52 are connected between the outflow side of the filter cell 10 and the inflow side of the battery cell 100c in the forward path pipes 108 and 109. Three-way valves 61 to 64 are attached to the connection points between the bypass pipes 51 and 52 and the forward pipes 108 and 109. The three-way valves 61 to 64 may be controlled by valve control means so as to be switched based on the detection results of the flow sensors 41 and 42.

  Specifically, the detection results of the flow sensors 41 and 42 are equal to or greater than a predetermined value, that is, the electrode electrolyte filters 14 and 15 of the filter cell 10 are not clogged, and the electrode electrolyte solution to the battery cell 100c is not clogged. When the supply amount is equal to or greater than a predetermined value, the three-way valves 61 to 64 are controlled so that the valves on the bypass pipes 51 and 52 side are closed so that the respective electrolytes do not flow through the bypass pipes 51 and 52. On the contrary, when the detection results of the flow sensors 41 and 42 are less than a predetermined value, that is, the electrodes 14 and 15 for the electrolyte solutions of the filter cell 10 are clogged, and the supply of the electrolyte solutions to the battery cell 100c is performed. When the amount becomes less than a predetermined value, the supply of each electrolyte solution to the filter cell 10 is cut off, and the electrodes on the bypass pipes 51 and 52 side are arranged so that each electrolyte solution flows through the bypass pipes 51 and 52. What is necessary is just to control the three-way valves 61-64 in the state which opened. In the meantime, it is only necessary to replace each of the electrode electrolyte filters 14 and 15 of the filter cell 10. That is, when the supply amount is equal to or greater than a predetermined value, each electrode electrolyte passes through the cell 10 for filter from each electrode electrolyte tank 106, 107, and impurities are filtered. It is supplied to each of the polar cells 102 and 103 of the cell 100c. On the other hand, when the supply amount is less than a predetermined value, the electrode electrolytes are supplied from the electrode electrolyte tanks 106 and 107 to the electrode cells 102 and 103 of the battery cell 100c through the bypass pipes 51 and 52, respectively. .

  According to this configuration, in addition to the effects of the fifth embodiment, as each electrode electrolyte solution 14, 15 of the filter cell 10 filters each electrode electrolyte solution, it gradually becomes clogged and electrolysis to the battery cell 100 c is performed. Even if the supply amount of the liquid decreases, the supply amount of the electrolyte solution to the battery cell can be ensured by switching the three-way valve and allowing the electrolyte solution to flow through the bypass pipes 51 and 52. And when replacing | exchanging each electrode electrolyte solution filters 14 and 15 of the cell 10 for filters, supply of each electrode electrolyte solution to the cell 10 for filters is interrupted | blocked, and each electrode electrolyte solution is distribute | circulated to the bypass pipes 51 and 52. Thus, the electrodes 14 and 15 for the electrolyte solution can be replaced without stopping charging / discharging of the battery cell 100c (operation of the RF battery 1F).

《Test example》
As a test example, an RF battery including a filter cell and a conventional RF battery including only the above-described basic configuration and not including a filter cell are continuously operated, and the inside of the battery cell of each RF battery The resistivity was compared. Here, the RF battery 1C (FIG. 3) of Embodiment 3 was used as the RF battery including the filter cell. And the felt made from carbon which has a surface area of about 10 times the surface area of each electrode 104,105 of the battery cell 100c was used for each electrode electrolyte solution filters 14,15 of the filter cell 10 in RF battery 1C. The result of the RF battery 1C is shown in FIG. 9A, and the result of the conventional RF battery is shown in FIG. 9B.

"result"
In the case of the RF battery 1C, the internal resistance of the battery cell hardly changed even when the continuous operation days were long, and the internal resistivity, which was about 1.3 Ω · cm ² at the start of the operation, was about 100 days of continuous operation. The same was true after the passage. On the other hand, in the case of a conventional RF battery, the internal resistivity of the battery cell gradually increases as the continuous operation days become longer, and the internal resistivity, which was about 1.3 Ω · cm ² at the start of operation, by the time that has elapsed about 100 days, 1.4Ω · cm ² ultra next, rose 0.1Ω · cm ² or more. The reason for this was that the RF battery 1C was able to remove impurities from each electrode electrolyte in the filter cell 10 and to suppress the adhesion of impurities to each electrode of the battery cell. Conceivable. On the other hand, in the conventional RF battery, it is considered that impurities deposited on each electrode electrolyte as the battery cell is charged / discharged adhere to each electrode of the battery cell as the day passes.

  In addition, in the RF battery 1C, when the battery cell 100c is provided instead of the filter cell 10 as a filter for filtering the electrolytic solution and the battery is continuously operated in the same manner, the rate of increase in the internal resistivity with respect to the continuous operation days is Although it is lower than (B) in FIG. 9, it is considered that the internal resistivity rises and gradually approaches the internal resistivity of the conventional RF battery when the day passes further than 100 days. Such a result is considered to be because each electrode 104, 105 can remove impurities only to a certain extent in each electrode electrolyte.

  In addition, this invention is not limited to the above-mentioned embodiment, The above-mentioned embodiment can be changed suitably, without deviating from the summary of this invention. For example, each of the electrode electrolyte solutions 14 and 15 may be made of a conductive material. In that case, the electrodes 14 and 15 for the electrode electrolyte solution can be charged to easily adsorb impurities.

  The RF battery of the present invention is suitable for applications aimed at stabilization of fluctuations in power generation output, power storage when surplus generated power, load leveling, etc. for power generation of new energy such as solar power generation and wind power generation. Can be used. The RF battery of the present invention can be suitably used as a large-capacity storage battery that is provided in a general power plant or the like for the purpose of instantaneous voltage drop / power failure countermeasures and load leveling.

1A, 1B, 1C, 1D, 1E, 1F Redox flow battery 10 Filter cell 11 Separator 12 Positive electrode filter cell 13 Negative electrode filter cell 14 Positive electrode electrolyte filter 15 Negative electrode electrolyte filter 20 Cell stack 30p, 30n Circulation path 31, 32 Outward pipe 33, 34 Return pipe 35, 36 Pump 41, 42 Flow sensor (flow meter)
51, 52 Bypass pipe 61, 62, 63, 64 Three-way valve 100 Redox flow battery 100c Battery cell 101 Diaphragm 102 Positive electrode cell 103 Negative electrode cell 104 Positive electrode 105 Negative electrode 106 Positive electrode electrolyte tank 107 Negative electrolyte tank 100p, 100n Circulation path 108, 109 Outward pipe 110, 111 Return pipe 112, 113 Pump 200 Cell stack 210 Cell frame 211 Bipolar plate 212 Frame body 213, 214 Liquid supply hole 215, 216 Drain hole 220 End plate 230 Tightening member

Claims (5)

A battery cell having a positive electrode cell incorporating a positive electrode, a negative electrode cell incorporating a negative electrode, and a diaphragm interposed between the positive electrode cell and the negative electrode cell, the positive electrode electrolyte and the negative electrode electrolyte being provided in each electrode cell A redox flow battery that supplies and charges and discharges,
Each electrode electrolyte tank storing each electrode electrolyte supplied to each electrode cell;
Each having an outward pipe for sending each of the electrode electrolytes from each of the electrode electrolyte tanks to each of the electrode cells, and a return pipe for returning each of the electrode electrolytes from each of the electrode cells to each of the electrode electrolyte tanks Circulation path,
A pump that is provided in each of the circulation paths and circulates each electrolyte solution;
A filter cell for filtering each electrode electrolyte supplied to each electrode cell,
The filter cell is configured with the same structure as the battery cell,
A positive electrode filter cell containing a positive electrode electrolyte filter through which the positive electrode electrolyte flows and filters the positive electrode electrolyte;
A negative electrode filter cell containing a negative electrode electrolyte filter through which the negative electrode electrolyte flows and filters the negative electrode electrolyte;
A separator that partitions the positive electrode filter cell and the negative electrode filter cell;
The redox flow battery, wherein the positive electrode electrolyte filter and the negative electrode electrolyte filter are more excellent in filtration characteristics for removing impurities than the positive electrode and the negative electrode of the battery cell.   The redox flow battery according to claim 1, wherein the filter cell is provided in the middle of the circulation path.   The redox flow battery according to claim 2, wherein the filter cell is provided in the middle of the outward pipe.   The redox flow battery according to any one of claims 1 to 3, further comprising detection means for detecting a degree of clogging of each electrode electrolyte solution filter of the filter cell. A bypass pipe for bypassing the inflow side and the outflow side of each electrolyte solution of the filter cell in the circulation path;
The redox flow battery according to any one of claims 2 to 4, further comprising a three-way valve attached to a connection point between the bypass pipe and the circulation path.

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