Charging module for flow-type metal-air battery and flow-type metal-air battery

Abstract

To provide a charging module for a flow-type metal-air battery and a flow-type metal-air battery that can suppress the reduction of metal ions dissolved in the positive electrode solution and the precipitation of metal particles, even when multiple charging cells are electrically connected in series.SOLUTION: A charging module for a flow-type metal-air battery includes a plurality of charging cells electrically connected in series, a negative electrode solution supplied to the plurality of charging cells and having a first active material ion concentration, and a positive electrode solution supplied to the plurality of charging cells and having a second active material ion concentration lower than the first active material ion concentration.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a charging module for a flow-type metal-air battery and a flow-type metal-air battery. [Background technology]

[0002] Patent Document 1 discloses an air storage battery. In this air storage battery, a separator separates the positive electrode from the negative electrode, retains an electrolyte, and ensures ionic conductivity between the positive electrode and the negative electrode. An anionic membrane is used as the separator (paragraphs 0048 and 0050). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6244174 Summary of the Invention [Problem to be solved by the invention]

[0004] In a flow-type metal-air battery, anode fluid is stored in a storage section, and the cathode fluid flows from the storage section to the storage section via a charging cell, and then from the storage section to the storage section via a discharging cell. Positive cathode fluid also flows through the charging cell. Charging occurs in the charging cell. Discharging occurs in the discharging cell.

[0005] In a flow-type metal-air battery, it is sometimes necessary to electrically connect multiple charge cells in series. However, when multiple charge cells are electrically connected in series, a potential difference occurs between the charge cell located on the higher potential side and the charge cell located on the lower potential side. As a result, an electrodeposition reaction, in which metal ions dissolved in the electrolyte are reduced and metal particles are precipitated within the positive electrode solution flow path, may occur near the charge cell located on the lower potential side. Furthermore, problems such as the precipitated metal particles clogging the positive electrode solution flow path or forming an electronic conduction path that short-circuits the positive electrodes of adjacent charge cells may occur.

[0006] One aspect of the present disclosure has been made in view of this problem, and aims to provide a charging module for a flow-type metal-air battery and a flow-type metal-air battery that can suppress the reduction of metal ions dissolved in the positive electrode solution and the precipitation of metal particles, even when, for example, a plurality of charging cells are electrically connected in series. [Means for solving the problem]

[0007] A charging module for a flow-type metal-air battery according to a first aspect of the present disclosure includes a plurality of charging cells electrically connected in series, a negative electrode solution supplied to the plurality of charging cells and having a first active material ion concentration, and a positive electrode solution supplied to the plurality of charging cells and having a second active material ion concentration lower than the first active material ion concentration.

[0008] A flow type metal-air battery according to a second embodiment of the present disclosure includes the charging module for a flow type metal-air battery according to the first embodiment of the present disclosure. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram schematically illustrating a flow-type metal-air battery according to a first embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view schematically illustrating the negative electrode solution flowing in a discharge module provided in the flow-type metal-air battery of the first embodiment. [Figure 3] FIG. 2 is an enlarged cross-sectional view schematically illustrating the negative electrode solution flowing in a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 4] FIG. 2 is an enlarged cross-sectional view schematically illustrating the positive electrode solution flowing in a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 5] FIG. 2 is a perspective view schematically illustrating a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 6] FIG. 2 is a plan view schematically illustrating a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view schematically illustrating a cross section of the charging module provided in the flow-type metal-air battery of the first embodiment, taken along the cutting line VII-VII in FIG. 6. [Figure 8] 8 is a cross-sectional view schematically illustrating a cross section of the charging module provided in the flow-type metal-air battery of the first embodiment, taken along the cutting line VIII-VIII in FIG. 6. FIG. [Figure 9] FIG. 2 is a plan view schematically illustrating a negative electrode current-carrying plate and a positive electrode current-carrying plate of a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 10] FIG. 2 is a plan view schematically illustrating the negative electrode of the charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 11] FIG. 2 is a plan view schematically illustrating a gasket of a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 12] FIG. 2 is a plan view schematically illustrating a negative electrode flow path plate of a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 13] FIG. 2 is a plan view schematically illustrating a separator of a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 14] FIG. 2 is a plan view schematically illustrating a positive electrode flow path plate of a charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 15]FIG. 2 is a plan view schematically illustrating the positive electrode of the charging module provided in the flow-type metal-air battery of the first embodiment. [Figure 16] FIG. 2 is a cross-sectional view schematically illustrating a cross section of a charging module provided in a flow-type metal-air battery of a reference example. [Figure 17] FIG. 10 is a perspective view schematically illustrating a charging module provided in a flow-type metal-air battery according to a second embodiment. [Figure 18] FIG. 10 is a plan view schematically illustrating a charging module provided in a flow-type metal-air battery according to a second embodiment. [Figure 19] 19 is a cross-sectional view schematically illustrating a cross section of a charging module provided in a flow-type metal-air battery according to a second embodiment, taken along the cutting line XIX-XIX in FIG. 18. FIG. [Figure 20] FIG. 10 is a plan view schematically illustrating a negative electrode current-carrying plate and an insulator of a charging module provided in a flow-type metal-air battery according to a second embodiment. [Figure 21] FIG. 10 is a plan view schematically illustrating a negative electrode current-carrying plate and an insulator of a charging module provided in a flow-type metal-air battery according to a modified example of the second embodiment. [Figure 22] FIG. 10 is a plan view schematically illustrating a positive electrode flow path plate provided in a flow-type metal-air battery according to a third embodiment. [Figure 23] FIG. 11 is a perspective view schematically illustrating a positive electrode flow path plate provided in a flow type metal-air battery according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0011] 1. First embodiment 1.1 Flow-type metal-air battery FIG. 1 is a diagram schematically illustrating a flow-type metal-air battery according to the first embodiment.

[0012] 1 , when discharging, the flow type metal-air battery 1 absorbs oxygen gas OG1 from the air surrounding the flow type metal-air battery 1. When charging, the flow type metal-air battery 1 releases oxygen gas OG2 into the air surrounding the flow type metal-air battery 1.

[0013] In the first embodiment, the flow type metal-air battery 1 is a flow type zinc-air battery. Therefore, the negative electrode active material in the flow type metal-air battery 1 is a zinc species. However, the flow type metal-air battery 1 may also be a flow type metal-air battery other than a flow type zinc-air battery. Therefore, the negative electrode active material in the flow type metal-air battery 1 may be a metal species other than a zinc species. Examples of metal species other than zinc species include cadmium species, lithium species, sodium species, magnesium species, lead species, tin species, aluminum species, and iron species. The metals constituting the metal species may be composed only of a main component metal, or may be composed of an alloy of a main component metal and a subcomponent metal. The metal species can be either a metal or an oxide. Whether the metal species is a metal or an oxide is determined depending on the degree of progress of the discharge reaction or the charge reaction.

[0014] As shown in FIG. 1, the flow-type metal-air battery 1 includes a storage section 11, a discharge section 12, a charge section 13, an anode liquid 14, and a cathode liquid 15.

[0015] 1.2 Storage section The storage unit 11 stores the negative electrode liquid 14 .

[0016] 1.3 Discharge section The discharge unit 12 absorbs oxygen gas OG1 from the air surrounding the discharge unit 12. The anode liquid 14 flows into the discharge unit 12 from the storage unit 11. The discharge unit 12 causes the absorbed oxygen gas OG1 and the anode liquid 14 that has flowed in to participate in a discharge reaction that generates discharge power, and causes the anode liquid 14 that has participated in the discharge reaction to flow out to the storage unit 11. The discharge unit 12 causes the oxygen gas OG1 and the reduced anode active material particles contained in the anode liquid 14 to participate in the discharge reaction, causing the reduced anode active material particles to disappear and generate active material ions.

[0017] As shown in FIG. 1, the discharge unit 12 includes a pipe 21 , a pump 22 , a pipe 23 , a discharge module 24 , and a pipe 25 .

[0018] Pipe 21 guides negative electrode liquid 14 from outlet 11a of storage unit 11 to inlet 22a of pump 22. Thus, pipe 21 causes negative electrode liquid 14 that has flowed out from outlet 11a to flow into inlet 22a.

[0019] The pump 22 causes the anode liquid 14, which has flowed into the inlet 22a of the pump 22, to flow out from the outlet 22b of the pump 22. At that time, the pump 22 generates a flow of the anode liquid 14. In this way, the pump 22 sends the anode liquid 14 from the storage unit 11 to the discharge module 24.

[0020] Pipe 23 guides negative electrode liquid 14 from outlet 22b of pump 22 to inlet 24a of discharge module 24. Thus, pipe 23 causes negative electrode liquid 14 flowing out from outlet 22b to flow into inlet 24a.

[0021] The discharge module 24 causes the anode liquid 14 that has flowed into an inlet 24a of the discharge module 24 to flow out from an outlet 24b of the discharge module 24. The discharge module 24 draws in air around the discharge unit 12 from an air inlet 24c of the discharge module 24, absorbs oxygen gas OG1 contained in the drawn air, and exhausts the air that has absorbed the oxygen gas OG1 from an exhaust port 24d of the discharge module 24. At that time, the discharge module 24 causes the absorbed oxygen gas OG1 and the anode liquid 14 that has flowed in to participate in a discharge reaction, and causes the anode liquid 14 that has participated in the discharge reaction to flow out from the outlet 24b. The discharge module 24 outputs discharge power generated by the discharge reaction.

[0022] Pipe 25 guides negative electrode liquid 14 from outlet 24b of discharge module 24 to inlet 11b of storage unit 11. Thus, pipe 25 causes negative electrode liquid 14 that flows out from outlet 24b to flow into inlet 11b.

[0023] 1.4 Live parts Anode liquid 14 flows into charging unit 13 from storage unit 11. Charging unit 13 causes the flowed-in anode liquid 14 to participate in a charging reaction that regenerates the anode liquid 14, and causes the anode liquid 14 involved in the charging reaction to flow out to storage unit 11. Charging unit 13 causes active material ions contained in anode liquid 14 to participate in a charging reaction, eliminating the active material ions, generating reduced anode active material particles, and generating oxygen gas OG2. Charging unit 13 exhausts the generated oxygen gas OG2 into the air surrounding charging unit 13.

[0024] As shown in FIG. 1, the charging unit 13 includes a pipe 31, a pump 32, a pipe 33, a pipe 34, a pump 35, a pipe 36, a power source 37, a charging module 38, a pipe 39, and a pipe 40.

[0025] Pipe 31 guides negative electrode liquid 14 from outlet 11c of storage unit 11 to inlet 32a of pump 32. Thus, pipe 31 causes negative electrode liquid 14 that has flowed out from outlet 11c to flow into inlet 32a.

[0026] The pump 32 causes the anode liquid 14 that has flowed into the inlet 32a of the pump 32 to flow out from the outlet 32b of the pump 32. At that time, the pump 32 generates a flow of the anode liquid 14. In this way, the pump 32 sends the anode liquid 14 from the storage unit 11 to the charging module 38.

[0027] Pipe 33 guides anode liquid 14 from outlet 32b of pump 32 to inlet 38a of charging module 38. Thus, pipe 33 causes anode liquid 14 that flows out from outlet 32b to flow into inlet 38a.

[0028] Pipe 34 guides positive electrode liquid 15 from a supply source of positive electrode liquid 15 (not shown) to inlet 35a of pump 35. Thus, pipe 34 causes positive electrode liquid 15 that flows out from the supply source of positive electrode liquid 15 to flow into inlet 35a.

[0029] The pump 35 causes the positive electrode solution 15, which has flowed into an inlet 35a of the pump 35, to flow out from an outlet 35b of the pump 35. At this time, the pump 35 generates a flow of the positive electrode solution 15. In this way, the pump 35 sends the positive electrode solution 15 from the supply source of the positive electrode solution 15 to the charging module 38.

[0030] Pipe 36 guides positive electrode solution 15 from outlet 35b of pump 35 to inlet 38c of charging module 38. Thus, pipe 36 causes positive electrode solution 15 that flows out from outlet 35b to flow into inlet 38c.

[0031] The power supply 37 inputs charging power to the charging module 38 .

[0032] The charging module 38 causes the anode liquid 14 that has flowed into an inlet 38a of the charging module 38 to flow out from an outlet 38b of the charging module 38, and causes the cathode liquid 15 that has flowed into an inlet 38c of the charging module 38 to flow out from an outlet 38d of the charging module 38. At that time, the charging module 38 causes the inflowing anode liquid 14 and cathode liquid 15 to participate in a charging reaction caused by charging power, causes the anode liquid 14 that has participated in the charging reaction to flow out from the outlet 38b, causes the cathode liquid 15 that has participated in the charging reaction to flow out from the outlet 38d, and exhausts oxygen gas OG2 generated by the charging reaction from the outlet 38d.

[0033] Pipe 39 guides negative electrode liquid 14 from outlet 38b of charging module 38 to inlet 11d of storage unit 11. Thus, pipe 39 causes negative electrode liquid 14 that flows out from outlet 38b to flow into inlet 11d.

[0034] The piping 40 guides the positive electrode liquid 15 from the outlet 38d of the charging module 38 to the supply source of the positive electrode liquid 15. Thus, the piping 40 causes the positive electrode liquid 15 that flows out from the outlet 38d to flow into the supply source of the positive electrode liquid 15.

[0035] 1.5 Negative electrolyte Fig. 2 is an enlarged cross-sectional view schematically illustrating the negative electrode solution flowing in a discharge module provided in the flow type metal-air battery of the first embodiment. Fig. 3 is an enlarged cross-sectional view schematically illustrating the negative electrode solution flowing in a charge module provided in the flow type metal-air battery of the first embodiment.

[0036] As shown in FIGS. 2 and 3, the negative electrode liquid 14 contains reduced negative electrode active material particles 51, oxidized negative electrode active material particles 52, active material ions 53, and an electrolyte 54.

[0037] As described above, in the first embodiment, the flow type metal-air battery 1 is a flow type zinc-air battery. Therefore, the reduced-state negative electrode active material particles 51, the oxidized-state negative electrode active material particles 52, and the active material ions 53 are zinc species. The reduced-state negative electrode active material particles 51 are metal zinc (Zn) particles. The oxidized-state negative electrode active material particles 52 are zinc oxide (ZnO) particles. The reduced-state negative electrode active material particles 51 and the oxidized-state negative electrode active material particles 52 are dispersed in the electrolyte 54. Therefore, the negative electrode liquid 14 has a slurry-like property. The reduced-state negative electrode active material particles 51 have a particle diameter of, for example, several μm. The oxidized-state negative electrode active material particles 52 have a particle diameter of, for example, several tens to several hundreds of nm. The active material ions 53 are zincate ions (Zn(OH)4 2- ) Active material ions 53 are dissolved in electrolyte solution 54 .

[0038] The electrolyte 54 is an aqueous solution of potassium hydroxide. The electrolyte 54 may be an aqueous solution other than the aqueous solution of potassium hydroxide, or may be an electrolyte other than an aqueous solution.

[0039] The active material ions 53 are reactants of the charge reaction occurring in the charge module 38 and are products of the discharge reaction occurring in the discharge module. The reduced negative electrode active material particles 51 are products of the charge reaction occurring in the charge module 38 and are reactants of the discharge reaction occurring in the discharge module.

[0040] 1.6 Positive electrolyte FIG. 4 is an enlarged cross-sectional view schematically illustrating the positive electrode solution flowing in the charging module provided in the flow-type metal-air battery of the first embodiment.

[0041] As shown in FIG. 4, the positive electrode solution 15 includes an electrolyte 61 .

[0042] The electrolyte 61 is an aqueous solution of potassium hydroxide. The electrolyte 61 may be an aqueous solution other than the aqueous solution of potassium hydroxide, or may be an electrolyte other than an aqueous solution.

[0043] 1.7 Discharge Reaction At the negative electrode of the discharge module 24, the negative electrode reactions represented by formulas (1) and (2) occur.

[0044] Zn+4OH - →Zn(OH)4 2- +2e - (1) Zn(OH)4 2- →ZnO+H2O+2OH - (2)

[0045] At the positive electrode of the discharge module 24, a positive electrode reaction represented by formula (3) occurs.

[0046] O2+2H2O+4e - →4OH - (3)

[0047] Due to the negative electrode reactions represented by formulas (1) and (2) and the positive electrode reaction represented by formula (3), a discharge reaction represented by formula (4) occurs in the discharge module 24.

[0048] 2Zn+O2→2ZnO (4)

[0049] 1.8 Charging Reaction At the negative electrode of the charging module 38, the negative electrode reactions represented by formulas (5) and (6) occur.

[0050] ZnO+H2O+2OH -→Zn(OH)4 2- (5) Zn(OH)4 2- +2e - →Zn+4OH - (6)

[0051] At the positive electrode of the charging module 38, a positive electrode reaction represented by formula (7) occurs.

[0052] 4OH - →O2+2H2+4e - (7)

[0053] Due to the negative electrode reactions represented by formulas (5) and (6) and the positive electrode reaction represented by formula (7), a charging reaction represented by formula (8) occurs in the charging module 38.

[0054] 2ZnO → 2Zn + O2 (8)

[0055] 1.9 Charging Module Fig. 5 is a perspective view schematically illustrating a charging module provided in the flow-type metal-air battery of the first embodiment. Fig. 6 is a plan view schematically illustrating a charging module provided in the flow-type metal-air battery of the first embodiment. Fig. 7 is a cross-sectional view schematically illustrating a cross section of the charging module provided in the flow-type metal-air battery of the first embodiment, taken along section line VII-VII in Fig. 6. Fig. 8 is a cross-sectional view schematically illustrating a cross section of the charging module provided in the flow-type metal-air battery of the first embodiment, taken along section line VIII-VIII in Fig. 6.

[0056] FIG. 9 is a plan view schematically illustrating the negative electrode current-carrying plate and the positive electrode current-carrying plate of a charging module provided in the flow-type metal-air battery of the first embodiment. FIG. 10 is a plan view schematically illustrating the negative electrode of the charging module provided in the flow-type metal-air battery of the first embodiment. FIG. 11 is a plan view schematically illustrating the gasket of the charging module provided in the flow-type metal-air battery of the first embodiment. FIG. 12 is a plan view schematically illustrating the negative electrode flow path plate of the charging module provided in the flow-type metal-air battery of the first embodiment. FIG. 13 is a plan view schematically illustrating the separator of the charging module provided in the flow-type metal-air battery of the first embodiment. FIG. 14 is a plan view schematically illustrating the positive electrode flow path plate of the charging module provided in the flow-type metal-air battery of the first embodiment. FIG. 15 is a plan view schematically illustrating the positive electrode of the charging module provided in the flow-type metal-air battery of the first embodiment.

[0057] 5 to 8, charging module 38 includes charging cells 71, 72, and 73, anode liquid 74, and cathode liquid 75. The number of charging cells included in charging module 38 may be increased or decreased from three. Anode liquid 74 and cathode liquid 75 are parts of anode liquid 14 and cathode liquid 15, respectively.

[0058] As shown in Figures 5 to 8, each charging cell 80 included in charging cells 71, 72, and 73 includes a negative electrode current-carrying plate 91, a negative electrode 92, a gasket 93, a negative electrode flow path plate 94, a gasket 95, a separator 96, a gasket 97, a positive electrode flow path plate 98, a gasket 99, a positive electrode 100, and a positive electrode current-carrying plate 101.

[0059] 1.10 Electrical series connection of multiple charging cells The negative electrode current-carrying plate 91 is electrically connected to the negative electrode 92. The positive electrode current-carrying plate 101 is electrically connected to the positive electrode 100. The positive electrode current-carrying plate 101 provided in charging cell 71 also serves as the negative electrode current-carrying plate 91 provided in charging cell 72. The positive electrode current-carrying plate 101 provided in charging cell 72 also serves as the negative electrode current-carrying plate 91 provided in charging cell 73. As a result, the positive electrode 100 provided in charging cell 71 is electrically connected to the negative electrode 92 provided in charging cell 72. The positive electrode 100 provided in charging cell 72 is electrically connected to the negative electrode 92 provided in charging cell 73. As a result, charging cells 71, 72, and 73 are electrically connected in series. The electrically connected in series configuration may be achieved by physical contact. For example, the components may be formed integrally.

[0060] 1.11 Positive and negative electrolyte flow paths The negative electrode current-carrying plate 91 has a plate-like shape and is formed with holes 91a, 91b, 91c, and 91d.

[0061] The gasket 93 has a sheet-like shape and is formed with holes 93a, 93b, 93c, and 93d, as well as an opening 93e.

[0062] The negative electrode flow path plate 94 has a plate-like shape and is formed with holes 94a, 94b, 94c, and 94d, a negative electrode chamber 94e, and connecting flow paths 94f and 94g.

[0063] The gasket 95 has a sheet-like shape and is formed with holes 95a, 95b, 95c, and 95d and an opening 95e.

[0064] The gasket 97 has a sheet-like shape and is formed with holes 97a, 97b, 97c, and 97d and an opening 97e.

[0065] The positive electrode flow path plate 98 has a plate-like shape and is formed with holes 98a, 98b, 98c, and 98d, a positive electrode chamber 98e, and connecting flow paths 98f and 98g.

[0066] The gasket 99 has a sheet-like shape and is formed with holes 99a, 99b, 99c, and 99d and an opening 99e.

[0067] The positive electrode current-carrying plate 101 has a plate-like shape and is formed with holes 101a, 101b, 101c, and 101d.

[0068] The negative electrode current-carrying plate 91, gasket 93, negative electrode flow path plate 94, gasket 95, gasket 97, positive electrode flow path plate 98, and gasket 99 provided in the charging cell 71; the negative electrode current-carrying plate 91 (positive electrode current-carrying plate 101 provided in the charging cell 71), gasket 93, negative electrode flow path plate 94, gasket 95, gasket 97, positive electrode flow path plate 98, and gasket 99 provided in the charging cell 72; and the negative electrode current-carrying plate 91 (positive electrode current-carrying plate 101 provided in the charging cell 72), gasket 93, negative electrode flow path plate 94, gasket 95, gasket 97, positive electrode flow path plate 98, gasket 99, and positive electrode current-carrying plate 101 provided in the charging cell 73 are stacked in the order listed.

[0069] The hole 91a formed in the negative electrode current-carrying plate 91, the hole 93a formed in the gasket 93, the hole 94a formed in the negative electrode flow path plate 94, the hole 95a formed in the gasket 95, the hole 97a formed in the gasket 97, the hole 98a formed in the positive electrode flow path plate 98, the hole 99a formed in the gasket 99, and the hole 101a formed in the positive electrode current-carrying plate 101 extend along the same straight line, have the same hole shape, and constitute a negative electrode liquid manifold 38p through which the negative electrode liquid 14 flows. The negative electrode liquid manifold 38p penetrates the negative electrode current-carrying plate 91, the gasket 93, the negative electrode flow path plate 94, the gasket 95, the gasket 97, the positive electrode flow path plate 98, the gasket 99, and the positive electrode current-carrying plate 101, and is formed across the charge cells 71, 72, and 73.

[0070] Hole 91b formed in negative electrode current-carrying plate 91, hole 93b formed in gasket 93, hole 94b formed in negative electrode flow path plate 94, hole 95b formed in gasket 95, hole 97b formed in gasket 97, hole 98b formed in positive electrode flow path plate 98, hole 99b formed in gasket 99, and hole 101b formed in positive electrode current-carrying plate 101 extend along the same straight line, have the same hole shape, and constitute negative electrode liquid manifold 38q through which negative electrode liquid 14 flows. Negative electrode liquid manifold 38q penetrates negative electrode current-carrying plate 91, gasket 93, negative electrode flow path plate 94, gasket 95, gasket 97, positive electrode flow path plate 98, gasket 99, and positive electrode current-carrying plate 101, and is formed across charge cells 71, 72, and 73.

[0071] The hole 91c formed in the negative electrode current-carrying plate 91, the hole 93c formed in the gasket 93, the hole 94c formed in the negative electrode flow path plate 94, the hole 95c formed in the gasket 95, the hole 97c formed in the gasket 97, the hole 98c formed in the positive electrode flow path plate 98, the hole 99c formed in the gasket 99, and the hole 101c formed in the positive electrode current-carrying plate 101 extend along the same straight line, have the same hole shape, and constitute a positive electrode liquid manifold 38r through which the positive electrode liquid 15 flows. The positive electrode liquid manifold 38r penetrates the negative electrode current-carrying plate 91, the gasket 93, the negative electrode flow path plate 94, the gasket 95, the gasket 97, the positive electrode flow path plate 98, the gasket 99, and the positive electrode current-carrying plate 101, and is formed across the charge cells 71, 72, and 73.

[0072] Hole 91d formed in negative electrode current-carrying plate 91, hole 93d formed in gasket 93, hole 94d formed in negative electrode flow path plate 94, hole 95d formed in gasket 95, hole 97d formed in gasket 97, hole 98d formed in positive electrode flow path plate 98, hole 99d formed in gasket 99, and hole 101d formed in positive electrode current-carrying plate 101 extend along the same straight line, have the same hole shape, and constitute positive electrode liquid manifold 38s through which positive electrode liquid 15 flows. Positive electrode liquid manifold 38s penetrates negative electrode current-carrying plate 91, gasket 93, negative electrode flow path plate 94, gasket 95, gasket 97, positive electrode flow path plate 98, gasket 97, and positive electrode current-carrying plate 101, and is formed across charge cells 71, 72, and 73.

[0073] The connecting flow path 94f formed in the negative electrode flow path plate 94 leads from the hole 94a formed in the negative electrode flow path plate 94 to the negative electrode chamber 94e formed in the negative electrode flow path plate 94. As a result, the connecting flow path 94f leads from the negative electrode liquid manifold 38p to the negative electrode chamber 94e. As a result, the negative electrode liquid manifold 38p communicates with the negative electrode chamber 94e via the connecting flow path 94f, and also communicates with the three negative electrode chambers 94e formed in the three charge cells 71, 72, and 73, respectively.

[0074] A connecting flow path 94g formed in the negative electrode flow path plate 94 leads from a hole 94b formed in the negative electrode flow path plate 94 to a negative electrode chamber 94e formed in the negative electrode flow path plate 94. As a result, the connecting flow path 94g leads from the negative electrode liquid manifold 38q to the negative electrode chamber 94e. As a result, the negative electrode liquid manifold 38q communicates with the negative electrode chamber 94e via the connecting flow path 94g, and also communicates with the three negative electrode chambers 94e formed in the three charge cells 71, 72, and 73, respectively.

[0075] As a result, the anode liquid 14 flows through the anode liquid manifold 38p, the three connecting flow paths 94f formed in the three charging cells 71, 72, and 73, the three anode chambers 94e formed in the three charging cells 71, 72, and 73, the three connecting flow paths 94g formed in the three charging cells 71, 72, and 73, and the anode liquid manifold 38q. As a result, the anode liquid 14 regenerated by the charging module 38 is supplied to the charging cells 71, 72, and 73. In addition, the anode liquid 14 regenerated by the charging module 38 is discharged from the charging cells 71, 72, and 73.

[0076] The connecting flow path 98f formed in the positive electrode flow path plate 98 leads from the hole 98c formed in the positive electrode flow path plate 98 to the positive electrode chamber 98e formed in the positive electrode flow path plate 98. As a result, the connecting flow path 98f leads from the positive electrode liquid manifold 38r to the positive electrode chamber 98e. As a result, the positive electrode liquid manifold 38r communicates with the positive electrode chamber 98e via the connecting flow path 98f, and also communicates with the three positive electrode chambers 98e formed in the three charging cells 71, 72, and 73, respectively.

[0077] A connecting flow path 98g formed in the positive electrode flow path plate 98 leads from a hole 98d formed in the positive electrode flow path plate 98 to a positive electrode chamber 98e formed in the positive electrode flow path plate 98. As a result, the connecting flow path 98g leads from the positive electrode liquid manifold 38s to the positive electrode chamber 98e. As a result, the positive electrode liquid manifold 38s communicates with the positive electrode chamber 98e via the connecting flow path 98g, and also communicates with the three negative electrode chambers 94e formed in the three charging cells 71, 72, and 73, respectively.

[0078] As a result, the positive electrode solution 15 flows through the positive electrode solution manifold 38r, the three connecting flow paths 98f formed in each of the three charging cells 71, 72, and 73, the three positive electrode chambers 98e formed in each of the three charging cells 71, 72, and 73, the three connecting flow paths 98g formed in each of the three charging cells 71, 72, and 73, and the positive electrode solution manifold 38s. As a result, the positive electrode solution 15 used by the charging module 38 is supplied to the charging cells 71, 72, and 73. In addition, the positive electrode solution 15 used by the charging module 38 is discharged from the charging cells 71, 72, and 73.

[0079] 1.12 Potential problems caused by electrically connecting multiple charging cells in series FIG. 16 is a cross-sectional view that schematically illustrates a cross section of a charging module provided in a flow-type metal-air battery of a reference example.

[0080] In the charging module 38x provided in the flow-type metal-air battery of the reference example, the positive electrode solution 75x contains active material ions 53 with a high concentration.

[0081] When the charging cells 71, 72, and 73 are electrically connected in series, the charging cells 71, 72, and 73 have different potentials. For example, as shown in Fig. 16, the negative electrodes 92 of the charging cells 71, 72, and 73 have potentials of 0 V, 2 V, and 4 V, respectively. The positive electrodes 100 of the charging cells 71, 72, and 73 have potentials of 2 V, 4 V, and 6 V, respectively.

[0082] When the charge cells 71, 72, and 73 have different potentials, the potential difference between the charge cell located on the low potential side and the charge cell located on the high potential side causes a side reaction in the flow path of the positive electrode solution 75x, which is formed in the charge module 38 and consists of the positive electrode solution manifolds 38r and 38s, the connecting flow paths 98f and 98g, and the positive electrode chamber 98e. Near the charge cell located on the low potential side, a side reaction represented by formula (9) occurs. Near the charge cell located on the high potential side, a side reaction represented by formula (10) occurs.

[0083] Zn(OH)4 2- +2H2O+2e - →Zn+4OH - (9) 4OH - →O2+2H2+4e - (10)

[0084] The side reaction represented by formula (9) occurring near the charging cell located on the low potential side converts zincate ions (Zn(OH)4 2- ) is reduced to deposit metallic zinc (Zn) particles 111. The deposited metallic Zn particles 111 block the flow path of the positive electrode solution and form an electronic conduction path that short-circuits the positive electrodes 100 provided in adjacent charging cells.

[0085] 1.13 Active material ion concentrations in anode and cathode electrolytes To prevent the above-described problems from occurring, in the charging module 38, as shown in FIGS. 3 and 4 , a second active material ion concentration indicating the concentration of active material ions 53 contained in the positive electrode liquid 75 is set lower than a first active material ion concentration indicating the concentration of active material ions 53 contained in the negative electrode liquid 74. The second active material ion concentration is set, for example, to be equal to or lower than half of the first active material ion concentration. The second active material ion concentration may be set to zero. By setting the second active material ion concentration in the positive electrode liquid 75 lower than the first active material ion concentration in the negative electrode liquid 74 in this manner, the reactants of the electrodeposition reaction can be reduced. This suppresses the electrodeposition reaction. This prevents metal Zn particles 111 deposited by the electrodeposition reaction from clogging the flow path of the positive electrode liquid 75 and from forming an electronic conduction path that short-circuits the positive electrodes 100 included in adjacent charging cells. The concentrations of active material ions 53 contained in the positive electrode liquid 75 / negative electrode liquid 74 here are the number of moles of active material ions 53 in 1 liter of the positive electrode liquid 75 / negative electrode liquid 74, respectively.

[0086] The first active material ion concentration of the negative electrode solution 74 is preferably equal to or greater than the saturation concentration of the active material ions 53 relative to the electrolyte 54, and the electrolyte 54 is a potassium hydroxide aqueous solution and the active material ions 53 are zincate ions (Zn(OH)4 2- ), zincate ion (Zn(OH)4 2- ) is 0.7 molar or more, which is the saturated concentration of

[0087] In a typical redox flow battery, the active material concentrations of the anode solution and the cathode solution are made to be approximately the same in order to maintain a balance between the anode and cathode capacities. In contrast, in a metal-air battery, metal ions are not involved in the anode reaction. Therefore, the active material ion concentrations of the anode solution 74 and the cathode solution 75 do not necessarily have to be made to be approximately the same. Taking advantage of this, the charging module 38 makes the second anode active material ion concentration of the cathode solution 75 lower than the first anode active material ion concentration of the anode solution 74.

[0088] 1.14 Charging cell structure The negative electrode current-carrying plate 91 has a rectangular planar shape. The negative electrode current-carrying plate 91 may have a planar shape other than a rectangular planar shape.

[0089] The negative electrode current-carrying plate 91 is made of a conductor.

[0090] The negative electrode 92 has a plate shape. The negative electrode 92 has a rectangular planar shape. The negative electrode 92 may have a planar shape other than a rectangular planar shape.

[0091] The negative electrode 92 is made of a conductor. The negative electrode 92 is made of a material capable of suppressing the hydrogen generation reaction that competes with the negative electrode reactions represented by formulas (5) and (6). Examples of materials capable of suppressing the hydrogen generation reaction include at least one selected from the group consisting of carbon, copper, and magnesium. Examples of carbon include graphite. Carbon is resistant to corrosion. Therefore, when the negative electrode 92 is made of carbon, it is possible to prevent the charging efficiency of each charging cell 80 from decreasing due to corrosion of the negative electrode 92. This improves the long-term stability of each charging cell 80. Furthermore, the adhesion of the reduced negative electrode active material particles 51 to magnesium is low. Therefore, when the negative electrode 92 is made of magnesium, it is possible to peel the reduced negative electrode active material particles 51 from the negative electrode 92 and facilitate the removal of the reduced negative electrode active material particles 51 from each charging cell 80.

[0092] The negative electrode 92 is placed on the main surface of the negative electrode current-carrying plate 91 and is housed in a groove formed in the negative electrode current-carrying plate 91. This brings the negative electrode 92 into contact with the negative electrode current-carrying plate 91. This makes the negative electrode current-carrying plate 91 a current-carrying path to the negative electrode 92.

[0093] The gasket 93 has a rectangular frame-like planar shape. The gasket 93 may have a planar shape other than a rectangular frame-like planar shape.

[0094] The gasket 93 is made of an elastic material.

[0095] The gasket 93 is sandwiched between the composite formed of the negative electrode current-carrying plate 91 and the negative electrode 92 and the negative electrode flow path plate 94. As a result, the gasket 93 liquid-tightly seals the gap between the composite and the negative electrode flow path plate 94.

[0096] The gasket 93 is made of an insulator. Therefore, the gasket 93 is insulated from the positive electrode liquid manifolds 38r and 38s formed in the charging module 38. The insulator here is 10 8 An object with a resistivity of Ωcm or more or a member with a resistivity equal to or greater than the insulation resistivity.

[0097] The negative electrode flow path plate 94 has a rectangular frame-like planar shape. The negative electrode flow path plate 94 may have a planar shape other than the rectangular frame-like planar shape.

[0098] The negative electrode flow path plate 94 is made of an insulator, and is therefore insulated from the positive electrode fluid manifolds 38r and 38s formed in the charging module 38.

[0099] The anode chamber 94e formed in the anode flow path plate 94 faces the center of the main surface of the anode 92, with an opening 93e formed in the gasket 93 interposed therebetween. This causes the anode 92 to face the anode chamber 94e. This causes the anode 92 to come into contact with the anode liquid 74 filling the anode chamber 94e.

[0100] The positive electrode current-carrying plate 101 has a rectangular planar shape. The positive electrode current-carrying plate 101 may have a planar shape other than a rectangular planar shape.

[0101] The positive electrode current-carrying plate 101 is made of a conductor.

[0102] The positive electrode 100 has a plate-like shape. The positive electrode 100 has a rectangular planar shape. The positive electrode 100 may have a planar shape other than a rectangular planar shape.

[0103] The positive electrode 100 is made of a conductor. The positive electrode 100 is made of a material with high oxygen generating capacity. This increases the charging efficiency of each charging cell 80. It also stabilizes the charging operation of each charging cell 80. Examples of materials with high oxygen generating capacity include nickel.

[0104] The gasket 99 has a rectangular frame-like planar shape. The gasket 99 may have a planar shape other than a rectangular frame-like planar shape.

[0105] The gasket 99 is made of an elastic material.

[0106] The gasket 99 is sandwiched between the composite formed of the positive electrode current-carrying plate 101 and the positive electrode 100 and the positive electrode flow path plate 98. As a result, the gasket 97 liquid-tightly seals the gap between the composite and the positive electrode flow path plate 98.

[0107] The gasket 99 is made of an insulating material, and is therefore insulated from the positive electrode liquid manifolds 38r and 38s formed in the charging module 38.

[0108] The positive electrode flow path plate 98 has a rectangular frame-like planar shape. The positive electrode flow path plate 98 may have a planar shape other than the rectangular frame-like planar shape.

[0109] The positive electrode chamber 98e formed in the positive electrode flow path plate 98 faces the center of the main surface of the positive electrode 100, with an opening 99e formed in the gasket 97 sandwiched therebetween. This causes the positive electrode 100 to face the positive electrode chamber 98e. This causes the positive electrode 100 to come into contact with the positive electrode liquid 75 filling the positive electrode chamber 98e.

[0110] The gaskets 95 and 97 are made of an elastic material.

[0111] The gaskets 95 and 97 are stacked on top of each other and sandwiched between the negative electrode flow path plate 94 and the positive electrode flow path plate 98. As a result, the gaskets 95 and 97 liquid-tightly seal the gap between the negative electrode flow path plate 94 and the positive electrode flow path plate 98.

[0112] The gaskets 95 and 97 are made of an insulating material, and therefore, the gaskets 95 and 97 are insulated from the positive electrode liquid manifolds 38r and 38s formed in the charging module 38.

[0113] The separator 96 has a sheet-like shape. The separator 96 is sandwiched between gaskets 95 and 97 and disposed between the negative electrode flow path plate 94 and the positive electrode flow path plate 98. The separator 96 separates the negative electrode chamber 94e formed in the negative electrode flow path plate 94 and the positive electrode chamber 98e formed in the positive electrode flow path plate 98 from each other.

[0114] The separator 96 does not allow the reduced negative electrode active material particles 51, the oxidized negative electrode active material particles 52, and the active material ions 53 to pass through or suppresses the permeation of the oxidized negative electrode active material particles 52 and the active material ions 53. As a result, the separator 96 suppresses the reduced negative electrode active material particles 51, the oxidized negative electrode active material particles 52, and the active material ions 53 from migrating from the negative electrode liquid 74 to the positive electrode liquid 75.

[0115] The separator 96 has high ionic conductivity. This allows the separator 96 to convert hydroxide ions OH - This allows hydroxide ions OH - allows the electrolyte to migrate from the negative electrode solution 74 to the positive electrode solution 75.

[0116] 1.15 Separator The separator 96 is a hydroxide ion (OH - ions 53. As a result, the separator 96 does not inhibit the permeation of hydroxide ions OH - The diffusion of active material ions 53 in separator 96 is made less likely to occur than the diffusion of active material ions 53 in the aqueous solution, and the diffusion of active material ions 53 in separator 96 is made less likely to occur than the diffusion of active material ions 53 in the aqueous solution. This makes it possible to prevent active material ions 53 from migrating from negative electrode liquid 74 to positive electrode liquid 75, thereby preventing the second active material ion concentration in positive electrode liquid 75 from increasing, without inhibiting the positive electrode reaction represented by formula (7).

[0117] Separator 96 is a non-porous separator that does not have pores through which active material ions 53 pass. A non-porous separator may have pores through which active material ions 53 do not pass, but does not have pores through which active material ions 53 pass. This makes it possible to prevent active material ions 53 from permeating separator 96 even when there is a concentration difference between the first active material ion concentration of negative electrode liquid 74 and the second active material ion concentration of positive electrode liquid 75. Therefore, a state in which there is a concentration difference between the first active material ion concentration of negative electrode liquid 74 and the second active material ion concentration of positive electrode liquid 75 can be maintained.

[0118] The pores through which the active material ions 53 do not pass are, for example, pores having a diameter of 10 μm or less. The diameter of the pores in the separator 96 is 0.1 μm or less, and preferably 0.05 μm or less. If the pore diameter is larger than these upper limits, it tends to become difficult to prevent the active material ions 53 from passing through the pores and increasing the second active material ion concentration in the positive electrode solution 75. The pore diameter can be measured by mercury intrusion porosimetry, a method using a perm porosimeter, a method using a pure water intrusion porosimeter, or the like.

[0119] The separator 96 is, for example, a hydrogel membrane. The hydrogel membrane includes a polymer having crosslinking points and cation exchange groups and / or anion exchange groups. The polymer swells with the water contained in the electrolyte solutions 54 and 61.

[0120] Alternatively, the separator 96 may be, for example, a composite membrane made of inorganic particles and a polymer. This composite membrane has both the hydrophilic properties of the inorganic particles and the hydrophobic properties of the polymer, and has high membrane strength due to the bonds between the inorganic particles and the polymer. The inorganic particles constituting the composite membrane may be, for example, a layered double hydroxide, and the polymer constituting the composite membrane may be, for example, a polymer having an amine group. When the inorganic particles constituting the composite membrane are layered double hydroxide and the polymer constituting the composite membrane is a polymer having an amine group, the content of the polymer constituting the composite membrane is preferably 7% by weight or more and 10% by weight or less. If the content is less than 7% by weight, the inorganic particles may be too high, which tends to reduce the strength of the composite membrane. If the content is more than 10% by weight, the ionic conductivity of the composite membrane may tend to be low.

[0121] 2. Second embodiment The following describes the differences between the second embodiment and the first embodiment. For points that are not described, the second embodiment also employs the same configuration as that employed in the first embodiment.

[0122] Fig. 17 is a perspective view schematically illustrating a charging module provided in the flow-type metal-air battery of the second embodiment. Fig. 18 is a plan view schematically illustrating a charging module provided in the flow-type metal-air battery of the second embodiment. Fig. 19 is a cross-sectional view schematically illustrating a cross section of the charging module provided in the flow-type metal-air battery of the second embodiment, taken along the section line XIX-XIX in Fig. 18.

[0123] FIG. 20 is a plan view schematically illustrating a negative electrode current-carrying plate and an insulator of a charging module provided in a flow-type metal-air battery of the second embodiment.

[0124] In the first embodiment, the negative electrode current-carrying plate 91 provided in the charging module 38 is in direct contact with the positive electrode liquid manifolds 38r and 38s formed in the charging module 38. Therefore, the negative electrode current-carrying plate 91 and the negative electrode 92 are electrically connected to the positive electrode liquid manifolds 38r and 38s.

[0125] In contrast, in the second embodiment, as shown in FIGS. 17 to 20 , each charging cell 80 includes insulators 103 and 104. The insulators 103 and 104 separate the negative electrode current-carrying plate 91 included in each charging cell 80 from the positive electrode fluid manifolds 38r and 38s formed in the charging module 38, respectively, and insulate the negative electrode current-carrying plate 91 from the positive electrode fluid manifolds 38r and 38s, respectively. This prevents the negative electrode current-carrying plate 91 from becoming electrically conductive with the positive electrode fluid 75 flowing through the positive electrode fluid manifolds 38r and 38s, which would otherwise cause an electrodeposition reaction. This prevents metal Zn particles 111 deposited by the electrodeposition reaction from clogging the flow path of the positive electrode fluid 75 and from forming an electronic conduction path that short-circuits the positive electrodes 100 included in adjacent charging cells.

[0126] The insulators 103 and 104 have a cylindrical shape. Therefore, holes 103a and 104a are formed in the insulators 103 and 104, respectively. The hole inner surfaces 91i and 91j of the negative electrode current-carrying plate 91 face the holes 91c and 91d formed in the negative electrode current-carrying plate 91, respectively, define the holes 91c and 91d, respectively, and surround the positive electrode liquid manifolds 38r and 38s formed in the charging module 38, respectively. The outer peripheral surfaces of the insulators 103 and 104 have a shape that matches the shape of the hole inner surfaces 91i and 91j of the negative electrode current-carrying plate 91. Therefore, the insulators 103 and 104 are disposed in the holes 91c and 91d, respectively, with the outer peripheral surfaces of the insulators 103 and 104 in surface contact with the hole inner surfaces 91i and 91j. Holes 103a and 104a define positive electrolyte manifolds 38r and 38s, respectively, formed in charging module 38.

[0127] The hole 91a formed in the negative electrode current-carrying plate 91 has a larger hole shape than the hole 93a formed in the gasket 93, the hole 94a formed in the negative electrode flow path plate 94, the hole 95a formed in the gasket 95, the hole 97a formed in the gasket 97, the hole 98a formed in the positive electrode flow path plate 98, the hole 99a formed in the gasket 99, and the hole 101a formed in the positive electrode current-carrying plate 101. The hole 103a formed in the insulator 103 has the same hole shape as the holes 93a, 94a, 95a, 97a, 98a, 99a, and 101a. The hole 91b formed in the negative electrode current-carrying plate 91 has a larger hole shape than the hole 93b formed in the gasket 93, the hole 94b formed in the negative electrode flow path plate 94, the hole 95b formed in the gasket 95, the hole 97b formed in the gasket 97, the hole 98b formed in the positive electrode flow path plate 98, the hole 99b formed in the gasket 99, and the hole 101b formed in the positive electrode current-carrying plate 101. The hole 104a formed in the insulator 104 has the same hole shape as the holes 93b, 94b, 95b, 97b, 98b, 99b, and 101b.

[0128] The positive electrode current-carrying plate 101 provided in the charging cell 71 also serves as the negative electrode current-carrying plate 91 provided in the charging cell 72 , and is electrically connected to the positive electrode 100 provided in the charging cell 71 and the negative electrode 92 provided in the charging cell 72 .

[0129] In a set consisting of a positive electrode flow plate 98 provided in the charging cell 71, a gasket 99 provided in the charging cell 71, a positive electrode current-carrying plate 101 provided in the charging cell 71, a gasket 93 provided in the charging cell 72, and a negative electrode flow plate 94 provided in the charging cell 72, holes 98c and 98d formed in the positive electrode flow plate 98 are first holes having a relatively small first hole shape. Holes 94c and 94d formed in the negative electrode flow plate 94 are second holes having a relatively small second hole shape. Holes 101c and 101d formed in the positive electrode current-carrying plate 101 are third holes having a relatively large third hole shape. The third hole shape is larger than the first hole shape and the second hole shape. In this set, the positive electrode current-carrying plate 101 has a first surface 101m and a second surface 101n facing the positive electrode flow plate 98 and the negative electrode flow plate 94, respectively. The insulator 103 has a third surface 103m and a fourth surface 103n facing the positive electrode flow plate 98 and the negative electrode flow plate 94, respectively. The insulator 104 has a third surface 104m and a fourth surface 104n facing the positive electrode flow plate 98 and the negative electrode flow plate 94, respectively. The first surface 101m and the third surfaces 103m and 104m form the same plane. The second surface 101n and the fourth surfaces 103n and 104n form the same plane. The gasket 99 is a first gasket that covers the first surface 101m and the third surfaces 103m and 104m. The gasket 93 is a second gasket that covers the second surface 101n and the fourth surfaces 103n and 104n. This makes it possible to prevent the positive electrode liquid 75 from flowing along the first surface 101m and the third surfaces 103m and 104m, thereby preventing the positive electrode liquid 75 from becoming electrically conductive with the positive electrode current-carrying plate 101. In addition, it is possible to prevent the positive electrode liquid 75 from flowing along the second surface 101n and the fourth surfaces 103n and 104n, thereby preventing the positive electrode liquid 75 from becoming electrically conductive with the positive electrode current-carrying plate 101.

[0130] The same can be said for the set of positive electrode flow path plate 98 provided in charging cell 72, gasket 99 provided in charging cell 72, positive electrode current-carrying plate 101 provided in charging cell 72, gasket 93 provided in charging cell 73, and negative electrode flow path plate 94 provided in charging cell 73.

[0131] FIG. 21 is a plan view schematically illustrating a negative electrode current-carrying plate and an insulator of a charging module provided in a flow-type metal-air battery according to a modified example of the second embodiment.

[0132] In the modified example of the second embodiment, as shown in FIG. 21, the insulators 103 and 104 are coatings that contact the inner surfaces 91i and 91j of the holes of the negative electrode current-carrying plate 91.

[0133] 3 Third embodiment The following describes the differences between the third embodiment and the second embodiment. For points that are not described, the third embodiment also employs the same configuration as that employed in the second embodiment.

[0134] FIG. 22 is a plan view schematically illustrating a positive electrode flow path plate provided in the flow type metal-air battery of the third embodiment.

[0135] 22 , a positive electrode chamber 98e formed in a positive electrode flow path plate 98 has a section that extends from a connection position P1 toward one side D11 in a specific direction. Furthermore, a connection flow path 98f formed in the positive electrode flow path plate 98 extends from the positive electrode liquid manifold 38r toward the other side D12 in the specific direction to reach the connection position P1, and is connected to the positive electrode chamber 98e at the connection position P1. Furthermore, a positive electrode chamber 98e formed in the positive electrode flow path plate 98 has a section that extends from a connection position P2 toward one side D21 in the specific direction. Furthermore, a connection flow path 98g formed in the positive electrode flow path plate 98 extends from the positive electrode liquid manifold 38s toward the other side D22 in the specific direction to reach the connection position P2, and is connected to the positive electrode chamber 98e at the connection position P2. As a result, the connecting flow paths 98f and 98g run parallel to the positive electrode chamber 98e until they are connected to the positive electrode chamber 98e, providing a longer flow path length compared to when they are connected to the positive electrode chamber 98e over the shortest distance. This makes it possible to lengthen the section length of the flow path for the positive electrode solution 75 from the charged cell on the high potential side to the charged cell on the low potential side. This makes it possible to suppress the side reactions represented by formulas (9) and (10) that are driven by the potential difference between the charged cell on the high potential side and the charged cell on the low potential side from occurring on the surface of the positive electrode 100 provided in the charged cell on the low potential side.

[0136] The inner wall facing the connecting flow paths 98f and 98g formed in the positive electrode flow path plate 98 is composed of the positive electrode flow path plate 98, which is an insulator, and the gaskets 97 and 99. Therefore, the inner wall is made of an insulator. This insulates the positive electrode current-carrying plate 101 from the positive electrode liquid manifolds 38r and 38s. This makes it possible to suppress the electrodeposition reaction. This makes it possible to prevent the metal Zn particles 111 deposited by the electrodeposition reaction from clogging the flow path of the positive electrode liquid 75 and to prevent the formation of an electronic conduction path that short-circuits the positive electrodes 100 included in adjacent charging cells.

[0137] FIG. 23 is a perspective view schematically illustrating a positive electrode flow path plate provided in a flow type metal-air battery according to a modified example of the third embodiment.

[0138] In the third embodiment, as shown in FIG. 22, all sections of the connecting channels 98f and 98g formed in the positive electrode channel plate 98 penetrate the positive electrode channel plate 98 in its thickness direction.

[0139] 23 , in the modified example of the third embodiment, some sections of the connecting channels 98f and 98g formed in the positive electrode flow path plate 98 near the positive electrode chamber 98e are grooves that do not penetrate the positive electrode flow path plate 98 in the thickness direction, and the remaining sections of the connecting channels 98f and 98g penetrate the positive electrode flow path plate 98 in the thickness direction. This allows the bottoms of the grooves to press down on the gasket 97.

[0140] 4 Fourth embodiment The following describes the differences between the fourth embodiment and the first embodiment. For points that are not described, the fourth embodiment also employs the same configuration as that employed in the first embodiment.

[0141] In the fourth embodiment, the positive electrode 100 contains at least one element having a low hydrogen overvoltage. This allows the hydrogen generation reaction, which competes with the side reactions represented by formulas (9) and (10), to occur preferentially. This allows hydrogen generation to occur preferentially over the deposition of metal Zn particles 111. This prevents the deposited metal Zn particles 111 from clogging the flow path of the positive electrode solution and prevents the formation of an electronic conduction path that short-circuits the positive electrodes provided in adjacent charging cells.

[0142] The at least one element having a low hydrogen overvoltage includes, for example, at least one element selected from Group 8 elements, Group 9 elements, and Group 10 elements of the long periodic table, and desirably includes at least one element selected from the group consisting of nickel (Ni), iridium (Ir), and platinum (Pt).

[0143] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that has the same effect, or a configuration that can achieve the same purpose. [Explanation of symbols]

[0144] 1 Flow-type metal-air battery 11 Storage 11a,11c Outlet 11b,11d Inlet 12 Discharge section 13 Live parts 14 Negative electrolyte 15 Positive electrolyte 21 Piping 22 Pump 22a Inlet 22b Outlet 23 Piping 24 Discharge Module 24a Inlet 24b Outlet 24c intake 24d exhaust port 25 Piping 31 Piping 32 Pump 32a Inlet 32b Outlet 33,34 Piping 35 Pump 35a Inlet 35b Outlet 36 Piping 37 Power supply 38,38x Charging Module 38a,38c Inlet 38b,38d Outlet 38p, 38q Anode liquid manifold 38r, 38s Positive Electrolyte Manifold 39,40 Piping 51 Reduced negative electrode active material particles 52 Oxidized negative electrode active material particles 53 Active material ions 54,61 Electrolyte 71, 72, 73 Charging cells 74 Negative electrolyte 75,75x catholyte 80 each charging cell 91 Negative electrode current-carrying plate 91a,91b,91c,91d hole 91i,91j Hole inner surface 92 Negative electrode 93 Gasket Holes 93a, 93b, 93c, and 93d 93e aperture 94 Negative electrode channel plate 94a,94b,94c,94d hole 94e Negative electrode chamber 94f, 94g connecting flow path 95 Gasket 95a,95b,95c,95d hole 95e opening 96 Separator 97 Gasket 97a,97b,97c,97d hole 97e aperture 98 Positive electrode flow plate 98a,98b,98c,98d hole 98e Positive electrode chamber 98f,98g connecting flow path 99 Gasket 99a,99b,99c,99d hole 99e Opening 100 positive electrode 101 Positive electrode conductive plate 101a,101b,101c,101d hole 101m 1st side 101n Second Side 103 Insulator 103a hole 103m Third side 103n The Fourth Side 104 Insulator 104a hole 104m Third Side 104n The Fourth Side 111 Metallic zinc (Zn) particles D11, D21 one side D12, D22 other side P1, P2 connection position OG1, OG2 oxygen gas

Claims

1. a plurality of charge cells electrically connected in series; an anode solution supplied to the plurality of charging cells and having a first active material ion concentration; a positive electrode solution supplied to the plurality of charge cells and having a second active material ion concentration lower than the first active material ion concentration; A charging module for a flow-type metal-air battery.

2. a negative electrode chamber through which the negative electrode solution flows and a positive electrode chamber through which the positive electrode solution flows are formed in each of the plurality of charging cells; Each of the charging cells includes a separator that separates the negative electrode chamber and the positive electrode chamber from each other and prevents the passage of active material ions. The charging module for a flow-type metal-air battery according to claim 1.

3. The separator is a hydrogel membrane. The charging module for a flow-type metal-air battery according to claim 2.

4. The separator is a composite membrane made of inorganic particles and a polymer. The charging module for a flow-type metal-air battery according to claim 2.

5. a plurality of charge cells electrically connected in series, each having a plurality of positive electrode chambers; an anode solution supplied to the plurality of charging cells and having a first active material ion concentration; a positive electrode solution supplied to the plurality of charging cells, flowing through the plurality of positive electrode chambers, and having a second active material ion concentration lower than the first active material ion concentration; Equipped with a positive electrode liquid manifold communicating with the positive electrode chambers is formed across the plurality of charge cells; each charging cell includes a negative electrode, a negative electrode current-carrying plate that is in electrical conduction with the negative electrode and through which the positive electrode liquid manifold passes, and a negative electrode flow path plate that has a negative electrode chamber in which the negative electrode liquid flows and through which the positive electrode liquid manifold passes, The negative electrode, the negative electrode current-carrying plate, and the negative electrode flow path plate are insulated from the positive electrode liquid manifold. Charging module for flow-type metal-air batteries.

6. Each of the charge cells includes an insulating material that insulates the current-carrying plate and the positive electrolyte manifold from each other. The charging module for a flow-type metal-air battery according to claim 5.

7. The insulating material has a cylindrical shape. The charging module for a flow-type metal-air battery according to claim 6.

8. the negative electrode current-carrying plate has a hole inner surface that surrounds the positive electrode liquid manifold, The insulating material is a coating that contacts the inner surface of the hole. The charging module for a flow-type metal-air battery according to claim 6.

9. a plurality of positive electrode chambers through which the positive electrode solution flows are formed in each of the plurality of charging cells; a positive electrode liquid manifold communicating with the positive electrode chambers is formed across the plurality of charge cells; The plurality of charging cells include: a positive electrode flow path plate in which the positive electrode chamber and first holes are formed, the positive electrode liquid flows through the positive electrode chamber, the first holes have a first hole shape, and the positive electrode flow path plate constitutes the positive electrode liquid manifold; an anode flow path plate having an anode chamber and second holes formed therein, the anode liquid flowing through the anode chamber, the second holes having a second hole shape, and constituting the cathode liquid manifold; a positive electrode facing the positive electrode chamber; a negative electrode facing the negative electrode chamber; a current-carrying plate that configures the positive electrode liquid manifold, the current-carrying plate having third holes formed therein and having a third hole shape larger than the first hole shape and the second hole shape, the current-carrying plate having a first surface and a second surface facing the positive electrode flow path plate and the negative electrode flow path plate, respectively, and that is in electrical conduction with the positive electrode and the negative electrode; an insulating material disposed in the third hole, the insulating material having a hole formed therein that constitutes the positive electrode liquid manifold, and the insulating material having a third surface and a fourth surface facing the positive electrode flow path plate and the negative electrode flow path plate, respectively; a first gasket covering the first surface and the third surface; a second gasket covering the second surface and the fourth surface; Equipped with The charging module for a flow-type metal-air battery according to any one of claims 1 to 8.

10. a positive electrode chamber through which the positive electrode solution flows is formed in each of the plurality of charging cells; a positive electrode liquid manifold is formed across the plurality of charging cells, the positive electrode liquid manifold communicating with a plurality of positive electrode chambers formed in each of the plurality of charging cells; A connecting flow path is formed in each of the charging cells, from the positive electrode liquid manifold to the positive electrode chamber; Each of the charging cells has an inner wall made of an insulator facing the connecting flow path. The charging module for a flow-type metal-air battery according to any one of claims 1 to 8.

11. a positive electrode chamber through which the positive electrode solution flows is formed in each of the plurality of charging cells; a positive electrode liquid manifold is formed across the plurality of charging cells, the positive electrode liquid manifold communicating with a plurality of positive electrode chambers formed in each of the plurality of charging cells; the positive electrode chamber has a section extending from the connection position toward one side, Each of the charge cells has a connecting passage extending from the positive electrolyte manifold to the other side and reaching the connecting position. The charging module for a flow-type metal-air battery according to any one of claims 1 to 8.

12. Each of the charge cells has a positive electrode containing at least one element having a low hydrogen overvoltage. The charging module for a flow-type metal-air battery according to any one of claims 1 to 8.

13. The at least one element includes at least one element selected from Group 8 elements, Group 9 elements, and Group 10 elements of the long periodic table. The charging module for a flow-type metal-air battery according to claim 12.

14. A flow-type metal-air battery comprising a charging module for a flow-type metal-air battery according to any one of claims 1 to 8.

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