Charging unit for flow-type metal-air battery

Abstract

This charging unit for a flow-type metal-air battery is provided with: a first layer in which a first flow path is formed; a positive electrode facing the first flow path; a second layer in which a second flow path is formed; a negative electrode facing the second flow path; a separator that separates the first flow path and the second flow path from each other; a positive electrode liquid flowing through the first flow path and having a first viscosity; and a negative electrode liquid that flows through the second flow path and has a second viscosity that is higher than the first viscosity.

Description

Technical Field

[0001] The present invention relates to a charging unit for a flow-type metal-air battery. Background Art

[0002] U.S. Patent No. 7470351 discloses a system for generating metal particles. In this system, metal particles are generated on the surface of a cathode by electrolyzing a solution containing dissolved metal. When the formed metal particles have a sufficient size, they are removed from the surface of the cathode by a scraper or other appropriate method. (Paragraphs 0014 and 0057). Summary of the invention

[0003] In the system disclosed in US Pat. No. 7,470,351, in order to remove metal particles from the surface of the cathode, a scraper or other suitable device must be moved along the surface of the cathode.

[0004] Therefore, there are problems such as the consumption of electric power required to operate the scraper or other appropriate device, and the reduction in durability caused by operating the scraper or other appropriate device along the surface of the cathode.

[0005] One aspect of the present disclosure is completed in view of the above problems. One aspect of the present disclosure is to provide, for example, a charging unit for a flow-type metal-air battery, which can peel off negative electrode active material particles from a negative electrode without consuming a large amount of power, and does not require physical contact with a scraper, etc., and thus has high durability.

[0006] A charging unit for a flow-type metal-air battery according to one aspect of the present disclosure comprises: a first layer forming a first flow path; a positive electrode facing the first flow path; a second layer forming a second flow path; a negative electrode facing the second flow path; a separator separating the first flow path and the second flow path from each other; a positive electrode liquid having a first viscosity flowing in the first flow path; and a negative electrode liquid having a second viscosity higher than the first viscosity flowing in the second flow path. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG. 1 is a diagram schematically illustrating a flow-type metal-air battery according to a first embodiment. Figure 2 This is an exploded perspective view schematically showing a charging unit included in the flowing metal-air battery according to the first embodiment. Figure 3 This is a cross-sectional view schematically showing a charging unit included in the flow-type metal-air battery according to the first embodiment. Figure 4AThis is a graph showing a first control example of the current value of the current flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment. Figure 4B This is a graph showing a first control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment. Figure 5A This is a graph showing a second control example of the current value flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment. Figure 5B This is a graph showing a second control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment. Fig. 6A This is a graph showing a third control example of the current value of the current flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment. Figure 6B This is a graph showing a third control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment. Figure 7 This is a graph showing a fourth control example of the current value of the current flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment. Figure 8 This is a graph showing a fifth control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment. Fig. 9 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a first modification of the first embodiment. Fig.10 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a second modification of the first embodiment. Fig.11 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a third modification of the first embodiment. Fig.12 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a fourth modification of the first embodiment. Fig.13 This is a cross-sectional view schematically showing a charging unit stack that can be used instead of the charging unit included in the flow-type metal-air battery of the first embodiment. DETAILED DESCRIPTION

[0008] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, in the accompanying drawings, the same or equivalent elements are marked with the same symbols, and repeated descriptions are omitted.

[0009] 1. First Embodiment 1.1 Flow Metal-Air Battery Figure 1 FIG. 1 is a diagram schematically illustrating a flow-type metal-air battery according to a first embodiment.

[0010] Figure 1 The flowing metal-air battery 1 of the first embodiment shown absorbs oxygen 11 from the air around the flowing metal-air battery 1 during discharge. The flowing metal-air battery 1 releases oxygen 12 to the air around the flowing metal-air battery 1 during charge.

[0011] The flowing metal-air battery 1 is a flowing zinc-air battery. Therefore, the negative electrode active material in the flowing metal-air battery 1 is a zinc substance. However, the flowing metal-air battery 1 may also be a flowing metal-air battery other than a flowing zinc-air battery. Therefore, the negative electrode active material in the flowing metal-air battery 1 may also be a metal species other than a zinc substance. Metal species other than zinc species are, for example, cadmium substances, lithium substances, sodium substances, magnesium substances, lead substances, tin substances, aluminum substances or iron substances. The metal constituting the metal substance may be composed only of a metal as a main component, or may be composed of an alloy of a metal as a main component and a secondary component. The metal substance may be any of a metal and an oxide. The metal substance is any of a metal and an oxide, and is determined according to the degree of progress of the discharge reaction or the charge reaction.

[0012] like Figure 1 As shown, the flowing metal-air battery 1 includes a positive electrode solution 21 , a negative electrode solution 22 , a storage section 23 , a discharge section 24 , and a charge section 25 .

[0013] 1.2 Cathode Solution like Figure 1 As shown, the cathode solution 21 includes a first electrolyte 31 .

[0014] The first electrolyte 31 is a potassium hydroxide aqueous solution. The first electrolyte 31 may be an aqueous solution other than the potassium hydroxide aqueous solution, or may be an electrolyte other than the aqueous solution.

[0015] Water contained in the first electrolyte solution 31 is a reactant of the charging reaction occurring in the charging section 25 .

[0016] 1.3 Negative Electrode Solution like Figure 1As shown, the negative electrode solution 22 includes negative electrode active material particles 41 a in a reduced state, negative electrode active material particles 41 b in an oxidized state, negative electrode active material ions 42 , and a second electrolyte solution 43 .

[0017] As described above, the flowing metal-air battery 1 is a flowing zinc-air battery. Therefore, the negative electrode active material particles 41a in a reduced state, the negative electrode active material particles 41b in an oxidized state, and the negative electrode active material ions 42 are zinc substances. The negative electrode active material particles 41a in a reduced state are metal zinc (Zn) particles, and the negative electrode active material particles 41b in an oxidized state are zinc oxide (ZnO) particles. The negative electrode active material particles 41a in a reduced state and the negative electrode active material particles 41b in an oxidized state are dispersed in the second electrolyte 43. Therefore, the negative electrode solution 22 has a slurry-like property. The negative electrode active material particles 41a in a reduced state have a particle size of, for example, several μm, and the negative electrode active material particles 41b in an oxidized state have a particle size of, for example, several tens to several hundreds of nm. The negative electrode active material ions 42 are zincate ions (Zn(OH) 4 2 _ ), dissolved in the second electrolyte 43.

[0018] The second electrolyte 43 is a potassium hydroxide aqueous solution. The second electrolyte 43 may be an aqueous solution other than the potassium hydroxide aqueous solution, or may be an electrolyte other than the aqueous solution.

[0019] The negative electrode active material ions 42 are reactants of a charge reaction occurring in the charge section 25 . The negative electrode active material particles 41 a in a reduced state are products of a charge reaction occurring in the charge section 25 .

[0020] 1.4 Storage Department The storage section 23 stores the negative electrode solution 22. The storage section 23 is formed with an outflow port 23a, an inflow port 23b, an outflow port 23c, and an inflow port 23d. The outflow port 23a and the outflow port 23c allow the negative electrode solution 22 to flow out. The inflow port 23b and the inflow port 23d allow the negative electrode solution 22 to flow in.

[0021] 1.5 Discharge section The discharge section 24 absorbs oxygen 11 from the air around the discharge section 24. The negative electrode solution 22 flows into the discharge section 24 from the storage section 23. The discharge section 24 allows the absorbed oxygen 11 and the flowing negative electrode solution 22 to participate in a discharge reaction for generating discharge power, and causes the negative electrode solution 22 participating in the discharge reaction to flow out to the storage section 23. The discharge section 24 allows the oxygen 11 and the negative electrode active material particles 41a in a reduced state contained in the negative electrode solution 22 to participate in the discharge reaction, causing the negative electrode active material particles 41a in a reduced state to disappear, and generating negative electrode active material ions 42.

[0022] like Figure 1As shown, the discharge section 24 includes a pipe 51 , a pump 52 , a pipe 53 , a discharge unit 54 , and a pipe 55 .

[0023] The pipe 51 guides the negative electrode solution 22 from the outlet 23a of the storage section 23 to the inlet 52a of the pump 52. Thus, the pipe 51 allows the negative electrode solution 22 that has flowed out of the outlet 23a to flow into the inlet 52a.

[0024] The pump 52 causes the negative electrode solution 22 that has flowed into the inlet 52a of the pump 52 to flow out from the outlet 52b of the pump 52. At this time, the pump 52 generates a flow of the negative electrode solution 22. Thus, the pump 52 delivers the negative electrode solution 22 from the storage section 23 to the discharge cell 54.

[0025] The pipe 53 guides the negative electrode solution 22 from the outlet 52b of the pump 52 to the inlet 54a of the discharge unit 54. Thus, the pipe 53 allows the negative electrode solution 22 that has flowed out from the outlet 52b to flow into the inlet 54a.

[0026] The discharge unit 54 absorbs oxygen 11 from the air around the discharge unit 54. The discharge unit 54 causes the cathode solution 22 that flows into the inlet 54a of the discharge unit 54 to flow out from the outlet 54b of the discharge unit 54. At this time, the discharge unit 54 causes the absorbed oxygen 11 and the inflow cathode solution 22 to participate in the discharge reaction, and causes the cathode solution 22 that participates in the discharge reaction to flow out from the outlet 54b. The discharge unit 54 outputs the discharge power generated by the discharge reaction.

[0027] The pipe 55 guides the negative electrode solution 22 from the outlet 54b of the discharge unit 54 to the inlet 23b of the storage section 23. Thus, the pipe 55 allows the negative electrode solution 22 that has flowed out of the outlet 54b to flow into the inlet 23b.

[0028] 1.6 Discharge unit like Figure 1 As shown, the discharge cell 54 includes a layer 61 , a negative electrode solution 62 , a positive electrode 63 , a separator 64 , and a negative electrode 65 .

[0029] A flow path 61a is formed in the layer 61. The flow path 61a extends from the inlet 54a of the discharge cell 54 to the outlet 54b of the discharge cell 54. Therefore, the flow path 61a allows the negative electrode solution 22 flowing into the inlet 54a to pass through, and allows the negative electrode solution 22 flowing through to flow out from the outlet 54b.

[0030] The negative electrode solution 62 flows in the flow path 61 a of the layer 61 . The negative electrode solution 62 is a part of the negative electrode solution 22 included in the flowing metal-air battery 1 .

[0031] Positive electrode 63 is in contact with the air around discharge cell 54. Oxygen gas 11 contained in the air around discharge cell 54 is thus supplied to positive electrode 63. As a result, in positive electrode 63, an oxygen reduction reaction represented by formula (1) occurs.

[0032] O 2 +2H 2 O+4e - →4OH-(1)

[0033] The positive electrode 63 faces the flow path 61a of the layer 61 via the separator 64. Thus, the positive electrode 63 delivers OH-, a product of the oxygen reduction reaction represented by formula (1), to the negative electrode solution 62 passing through the separator 64 and flowing through the flow path 61a.

[0034] The negative electrode 65 faces the flow path 61a of the layer 61. Thus, the negative electrode 65 is in contact with the negative electrode solution 62 flowing through the flow path 61a. Thus, in the negative electrode 65, an oxidation reaction of the metal zinc represented by the formula (2) and the formula (3) occurs.

[0035] Zn+40H-→Zn(OH)4 2- +2 e- (2) Zn(OH) 4 2- →ZnO+H 2 O+2OH- (3)

[0036] The entire reaction represented by the formula (4) occurs in the discharge cell 54 due to the reduction reaction of oxygen in the positive electrode 63 and the oxidation reaction of the metal zinc in the negative electrode 65 .

[0037] 2Zn+O 2 →2ZnO(4)

[0038] Therefore, discharge unit 54 discharges when metal zinc changes into zinc oxide.

[0039] 1.7 Charging Section The negative electrode liquid 22 flows from the storage section 23 into the charging section 25. The charging section 25 allows the flowing negative electrode liquid 22 to participate in the charging reaction of regenerating the negative electrode liquid 22, and allows the negative electrode liquid 22 participating in the charging reaction to flow out to the storage section 23. The charging section 25 allows the negative electrode active material ions 42 contained in the negative electrode liquid 22 to participate in the charging reaction, causing the negative electrode active material ions 42 to disappear, and generating negative electrode active material particles 41a in a reduced state.

[0040] like Figure 1 As shown, the charging section 25 includes a pipe 71 , a pump 72 , a pipe 73 , a pipe 74 , a pump 75 , a pipe 76 , a power source 77 , a charging unit 78 , a pipe 79 , a pipe 80 , and a control circuit 81 .

[0041] The pipe 71 guides the cathode solution 21 from a supply source of the cathode solution 21 (not shown) to the inlet 72a of the pump 72. Thus, the pipe 71 allows the cathode solution 21 flowing out from the supply source of the cathode solution 21 to flow into the inlet 72a.

[0042] The pump 72 causes the cathode solution 21 flowing into the inlet 72a of the pump 72 to flow out from the outlet 72b of the pump 72. The pump 72 generates a flow of the cathode solution 21. Thus, the pump 72 delivers the cathode solution 21 from the supply source of the cathode solution 21 to the charging unit 78.

[0043] The pipe 73 guides the cathode solution 21 from the outlet 72b of the pump 72 to the inlet 78a of the charging unit 78. Thus, the pipe 73 allows the cathode solution 21 that has flowed out from the outlet 72b to flow into the inlet 78a.

[0044] The pipe 74 guides the negative electrode solution 22 from the outlet 23c of the storage section 23 to the inlet 75a of the pump 75. Thus, the pipe 74 allows the negative electrode solution 22 that has flowed out of the outlet 23c to flow into the inlet 75a.

[0045] The pump 75 causes the negative electrode solution 22 that has flowed into the inlet 75a of the pump 75 to flow out from the outlet 75b of the pump 75. At this time, the pump 75 generates a flow of the negative electrode solution 22. Thus, the pump 75 delivers the negative electrode solution 22 from the storage section 23 to the charging unit 78.

[0046] The pipe 76 guides the negative electrode solution 22 from the outlet 75b of the pump 75 to the inlet 78b of the charging unit 78. Thus, the pipe 76 allows the negative electrode solution 22 that has flowed out of the outlet 75b to flow into the inlet 78b.

[0047] The power source 77 inputs charging power to the charging unit 78 .

[0048] The charging unit 78 causes the positive electrode solution 21 flowing into the inlet 78a of the charging unit 78 to flow out from the outlet 78c of the charging unit 78, and causes the negative electrode solution 22 flowing into the inlet 78b of the charging unit 78 to flow out from the outlet 78d of the charging unit 78. At this time, the charging unit 78 causes the flowing positive electrode solution 21 and the negative electrode solution 22 to participate in the charging reaction generated by the charging power, causes the positive electrode solution 21 participating in the charging reaction to flow out from the outlet 78c, causes the negative electrode solution 22 participating in the charging reaction to flow out from the outlet 78d, and discharges the oxygen 12 generated by the charging reaction to the air around the charging unit 78.

[0049] The pipe 79 guides the cathode solution 21 from the outflow port 78c of the charging unit 78 to the supply source of the cathode solution 21. Thus, the pipe 79 allows the cathode solution 21 flowing out of the outflow port 78c to flow into the supply source of the cathode solution 21.

[0050] The pipe 80 guides the negative electrode solution 22 from the outflow port 78d of the charging unit 78 to the inflow port 23d of the storage section 23. Thus, the pipe 80 allows the negative electrode solution 22 that has flowed out of the outflow port 78d to flow into the inflow port 23d.

[0051] The pipe 71 , the pump 72 , the pipe 73 , and the pipe 79 constitute a mechanism for generating a flow of the cathode solution 21 so that the cathode solution 21 flows into the inlet 78 a of the charging unit 78 and flows out from the outlet 78 c of the charging unit 78 .

[0052] The pipe 74 , the pump 75 , the pipe 76 , and the pipe 80 constitute a mechanism for generating a flow of the negative electrode solution 22 so that the negative electrode solution 22 flows into the inlet 78 b of the charging unit 78 and flows out from the outlet 78 d of the charging unit 78 .

[0053] The control circuit 81 controls the pumps 72 and 75. Thus, the control circuit 81 constitutes a control unit that changes the flow rate of the cathode solution 92 in the first flow path 91e of the charging unit 78 and / or the flow rate of the cathode solution 97 in the second flow path 96e of the charging unit 78.

[0054] The control circuit 81 controls the power supply 77. Thus, the control circuit 81 constitutes a current supply control unit that changes the current value of the current flowing between the positive electrode 93 of the charging unit 78 and the negative electrode 98 of the charging unit 78.

[0055] The control circuit 81 includes a microcontroller and a peripheral circuit. The microcontroller includes a processor and a memory. The processor executes a program stored in the memory to cause the microcontroller and the peripheral circuit to operate as the above-mentioned control unit and power-on control unit. All or part of the processing performed by the microcontroller can also be performed by a dedicated electronic circuit.

[0056] 1.8 Charging Unit Figure 2 This is an exploded perspective view schematically showing a charging unit included in the flowing metal-air battery according to the first embodiment. Figure 3 It is a cross-sectional view schematically showing a charging unit included in the flowing metal-air battery according to the first embodiment.

[0057] like Figure 2 and Figure 3 As shown, charging unit 78 includes first layer 91 , positive electrode solution 92 , positive electrode 93 , current-carrying plate 94 , gasket 95 , second layer 96 , negative electrode solution 97 , negative electrode 98 , current-carrying plate 99 , gasket 100 , separator 101 , gasket 102 and gasket 103 .

[0058] The first layer 91 has a rectangular frame shape. Therefore, the first layer 91 has an opening surface 91p, an opening surface 91q, an end surface 91a, and an end surface 91c. The opening surface 91p and the opening surface 91q are located on opposite sides. The end surface 91a and the end surface 91c are located on opposite sides. The first layer 91 may also have a frame shape other than the rectangular frame shape.

[0059] A first flow path 91 e is formed in the first layer 91 .

[0060] The first flow path 91e of the first layer 91 is exposed at the opening surface 91p and the opening surface 91q, and has an opening 91pe and an opening 91qe at the opening surface 91p and the opening surface 91q, respectively.

[0061] The first flow path 91e is exposed at the end surface 91a and the end surface 91c, and has an inlet 78a and an outlet 78c at the end surface 91a and the end surface 91c, respectively. Therefore, the first flow path 91e reaches the outlet 78c from the inlet 78a. Therefore, the first flow path 91e allows the positive electrode solution 92 flowing into the inlet 78a to pass through, and allows the positive electrode solution 21 that has passed through to flow out from the outlet 78c.

[0062] The inlet 78a and the outlet 78c of the charging unit 78 are respectively arranged on the vertical lower side and the vertical upper side. Therefore, the first flow path 91e of the first layer 91 has a portion that guides the positive electrode solution 92 in the vertical direction. The inlet 78a can be arranged at a position other than the vertical lower side, and the outlet 78c can also be arranged at a position other than the vertical upper side.

[0063] The positive electrode solution 92 flows in the first flow path 91e of the first layer 91. The positive electrode solution 92 is a part of the positive electrode solution 21. As described above, the inlet 78a and the outlet 78c of the charging unit 78 are respectively arranged on the vertically lower side and the vertically upper side. Therefore, the flow direction of the positive electrode solution 92 guided to the part in the vertical direction is from the vertically lower side to the vertically upper side.

[0064] In the case where the flow direction of the positive electrode solution 92 is from the vertical upper direction to the vertical lower direction, the positive electrode solution 92 flows down from the first flow path 91e even before the first flow path 91e of the first layer 91 is completely filled with the positive electrode solution 92. Therefore, there is a possibility that the first flow path 91e cannot be completely filled with the positive electrode solution 92. In contrast, in the case where the flow direction of the positive electrode solution 92 is from the vertical lower direction to the vertical upper direction, after the first flow path 91e is completely filled with the positive electrode solution 92, the positive electrode solution 92 overflows from the first flow path 91e. Therefore, the first flow path 91e can be completely filled with the positive electrode solution 92.

[0065] The oxygen gas 12 generated at the cathode 93 not only moves from the vertical bottom to the top by buoyancy but also moves from the vertical bottom to the top by the flow of the cathode solution 92. This can promote the discharge of the oxygen gas 12 from the charging unit 78.

[0066] The positive electrode 93 has a rectangular plate shape. The positive electrode 93 is arranged on the opening surface 91p of the first layer 91. Thus, the positive electrode 93 closes the opening 91pe of the first layer 91 and faces the first flow path 91e of the first layer 91. Thus, the positive electrode 93 contacts the positive electrode solution 92 flowing through the first flow path 91e. Thus, in the positive electrode 93, an oxidation reaction of water represented by formula (5) occurs.

[0067] 40H-→O 2 +2H 2 +4e - (5)

[0068] Therefore, the charging unit 78 generates oxygen gas 12 by the oxidation reaction of water in the positive electrode 93. The generated oxygen gas 12 is discharged from the charging unit 78.

[0069] The positive electrode 93 is made of a material having a high oxygen generation capability. This can improve the charging efficiency of the charging unit 78. In addition, the charging operation of the charging unit 78 can be stabilized. The material having a high oxygen generation capability contains nickel, for example.

[0070] The conducting plate 94 has a rectangular plate shape and is disposed on the opening surface 91p of the first layer 91 so as to overlap with the positive electrode 93. Thus, the conducting plate 94 is in contact with the positive electrode 93, and a conducting path to the positive electrode 93 is formed.

[0071] The gasket 95 is interposed between the opening surface 91 p of the first layer 91 , the positive electrode 93 , and the current-carrying plate 94 , and seals the opening surface 91 p of the first layer 91 , the positive electrode 93 , and the current-carrying plate 94 in a liquid-tight manner.

[0072] The second layer 96 has a rectangular frame shape. Therefore, the second layer 96 has an opening surface 96p, an opening surface 96q, an end surface 96b, and an end surface 96d. The opening surface 96p and the opening surface 96q are located on opposite sides. The end surface 96b and the end surface 96d are located on opposite sides.

[0073] The second layer 96 has a second flow path 96 e formed therein.

[0074] The second flow path 96e of the second layer 96 is exposed at the opening surface 96p and the opening surface 96q, and has an opening 96pe and an opening 96qe at the opening surface 96p and the opening surface 96q, respectively.

[0075] The second flow path 96e is exposed at the end surface 96b and the end surface 96d, and has an inlet 78b and an outlet 78d at the end surface 96b and the end surface 96d, respectively. Therefore, the second flow path 96e reaches the outlet 78d from the inlet 78b. Therefore, the second flow path 96e allows the negative electrode solution 97 flowing into the inlet 78b to pass through, and allows the negative electrode solution 97 flowing through to flow out from the outlet 78d.

[0076] The inlet 78b and the outlet 78d of the charging unit 78 are arranged on the vertically lower side and the vertically upper side, respectively. Therefore, the second flow path 96e of the second layer 96 includes a portion for guiding the negative electrode solution 97 in the vertical direction.

[0077] The negative electrode solution 97 flows in the second flow path 96e of the second layer 96. The negative electrode solution 97 is a part of the negative electrode solution 22. As described above, the inlet 78b and the outlet 78d of the charging unit 78 are respectively arranged on the vertically lower side and the vertically upper side. Therefore, the flow direction of the negative electrode solution 97 in the portion where the negative electrode solution 97 is guided in the vertical direction is from the vertically lower side to the vertically upper side.

[0078] In the case where the negative electrode solution 97 flows from the vertical upper direction to the vertical lower direction, the negative electrode solution 97 flows down from the second flow path 96e even before the second flow path 96e of the second layer 96 is completely filled with the negative electrode solution 97. Therefore, there is a possibility that the second flow path 96e cannot be completely filled with the negative electrode solution 97. In contrast, in the case where the negative electrode solution 97 flows from the vertical lower direction to the vertical upper direction, after the second flow path 96e is completely filled with the negative electrode solution 97, the negative electrode solution 97 overflows from the second flow path 96e. Therefore, the second flow path 96e can be completely filled with the negative electrode solution 97.

[0079] The specific gravity of the negative electrode active material particles 41a in the reduced state generated in the negative electrode 98 is greater than the specific gravity of the negative electrode solution 97. Therefore, when the flow direction of the negative electrode solution 97 is from the vertical upper direction to the vertical lower direction, the negative electrode active material particles 41a in the reduced state move from the vertical upper direction to the vertical lower direction and precipitate. However, when the flow direction of the negative electrode solution 97 is from the vertical lower direction to the vertical upper direction, the negative electrode active material particles 41a in the reduced state overcome gravity and move from the vertical lower direction to the vertical upper direction as the positive electrode solution 92 flows. As a result, the negative electrode active material particles 41a in the reduced state can be discharged from the charging unit 78 after the particle size grows to a size that can fully resist the resistance caused by the negative electrode solution 97.

[0080] The negative electrode 98 has a rectangular plate shape. The negative electrode 98 is arranged on the opening surface 96p of the second layer 96. Thus, the negative electrode 98 closes the opening 96pe of the second layer 96 and faces the second flow path 96e of the second layer 96. Thus, the negative electrode 98 contacts the negative electrode liquid 97 flowing through the second flow path 96e. Thus, in the negative electrode 98, zincate ions Zn(OH) generated by the oxidation reaction of the metal zinc represented by formula (2) and formula (3) are contained. 4 2-The negative electrode solution of zinc oxide ZnO is supplied to the negative electrode 98. As a result, in the negative electrode 98, a reduction reaction to metallic zinc represented by equations (6) and (7) occurs.

[0081] ZnO+H 2 O+2OH-→Zn(OH) 4 2- (6) Zn(OH) 4 2- -+2e - →Zn+40H-(7)

[0082] Therefore, the charging unit 78 generates negative electrode active material particles 41 a in a reduced state by a reduction reaction to metal zinc in the negative electrode 98 . The generated negative electrode active material particles 41 a in a reduced state adhere to the negative electrode 98 .

[0083] The negative electrode 98 is composed of a material that can suppress the hydrogen generation reaction that competes with the reduction reaction to the metal zinc. The material that can suppress the hydrogen generation reaction includes, for example, at least one selected from the group consisting of carbon, copper and magnesium. Carbon includes, for example, graphite. Carbon is difficult to corrode. Therefore, in the case where the negative electrode 98 is composed of carbon, it is possible to suppress the charging efficiency of the charging unit 78 from being reduced due to the corrosion of the negative electrode 98. Thus, the long-term stability of the charging unit 78 can be improved. In addition, the negative electrode active material particles 41a in the reduced state have low adhesion to magnesium. Therefore, in the case where the negative electrode 98 is composed of magnesium, it is possible to promote the negative electrode active material particles 41a in the reduced state to be peeled off from the negative electrode 98 and the negative electrode active material particles 41a in the reduced state can be removed from the charging unit 78.

[0084] The conducting plate 99 has a rectangular plate shape and is disposed on the opening surface 96p of the second layer 96 so as to overlap with the negative electrode 98. Thus, the conducting plate 99 is in contact with the negative electrode 98, and a conducting path to the negative electrode 98 is formed.

[0085] The gasket 100 is interposed between the opening surface 96 p of the second layer 96 , the negative electrode 98 , and the current-carrying plate 99 , and seals the opening surface 96 p of the second layer 96 , the negative electrode 98 , and the current-carrying plate 99 in a liquid-tight manner.

[0086] The separator 101 has a sheet-like shape. The separator 101 has flexibility. The separator 101 is arranged on the opening surface 91q of the first layer 91. Thus, the separator 101 closes the opening 91qe of the first layer 91 and faces the first flow path 91e of the first layer 91. In addition, the separator 101 is arranged on the opening surface 96q of the second layer 96. Thus, the separator 101 closes the opening 96qe of the second layer 96 and faces the second flow path 96e of the second layer 96.

[0087] The separator 101 is sandwiched between the first layer 91 and the second layer 96. Thus, the separator 101 separates the first flow path 91e of the first layer 91 from the second flow path 96e of the second layer 96. The separator 101 does not penetrate the negative electrode active material particles 41a in a reduced state, the negative electrode active material particles 41b in an oxidized state, and the thickener 44. Thus, the separator 101 inhibits the negative electrode active material particles 41a in a reduced state, the negative electrode active material particles 41b in an oxidized state, and the thickener 44 from moving from the negative electrode solution 97 to the positive electrode solution 92.

[0088] The separator 101 has high ion conductivity. Therefore, the hydroxide ions OH − pass through the separator 101 . Therefore, the hydroxide ions OH − can move from the negative electrode solution 97 to the positive electrode solution 92 .

[0089] The separator 101 needs to prevent the penetration of the negative electrode active material particles 41a in a reduced state, the negative electrode active material particles 41b in an oxidized state, and the thickener 44, and is therefore preferably a membrane having no pores of 50 nm or more, more preferably 100 nm or more. The separator 101 is, for example, an anion exchange membrane, a hydrogel membrane, or a membrane having a plurality of inorganic ion conductor particles and a resin impregnated in the grain boundaries of the plurality of inorganic ion conductor particles.

[0090] In the reduction reaction to metal zinc in the negative electrode 98, i.e., the electrodeposition reaction of metal zinc, due to the uneven distribution of the current, the metal zinc in the form of a tree, i.e., a dendrite, grows from the negative electrode 98. The separator 101 has high dendrite resistance. Therefore, the separator 101 prevents the dendrite-like metal zinc from growing beyond the separator 101. Thus, it is possible to suppress the positive electrode 93 and the negative electrode 98 from being short-circuited to each other via the dendrite-like metal zinc.

[0091] The gasket 102 is interposed between the opening surface 91q of the first layer 91 and the separator 101 , and seals the opening surface 91q of the first layer 91 and the separator 101 in a liquid-tight manner.

[0092] The gasket 103 is interposed between the opening surface 96q of the second layer 96 and the separator 101 , and seals the opening surface 96q of the second layer 96 and the separator 101 in a liquid-tight manner.

[0093] 1.9 Theoretical Voltage of Flow Metal-Air Battery The entire reaction represented by equation (8) occurs in the charging unit 78 through the oxidation reaction of water in the positive electrode 93 and the reduction reaction to metal zinc in the negative electrode 98 .

[0094] 2Zn+O 2 →2ZnO(8)

[0095] Therefore, the charging unit 78 changes zinc oxide into metallic zinc during charging.

[0096] The potentials of the positive electrode and the negative electrode during the discharge reaction and the charge reaction are respectively -1.25 V and 0.40 V based on the standard hydrogen electrode standard. Therefore, the theoretical voltage of the flowing metal-air battery 1 is 1.65V.

[0097] 1.10 Viscosity of positive and negative electrolytes The positive electrode solution 92 has a first viscosity. The negative electrode solution 97 has a second viscosity higher than the first viscosity. The first viscosity is, for example, 1 mPasec or more and 9 mPasec or less, preferably 2 mPasec or more and 3 mPasec or less. The second viscosity is, for example, 100 mPasec or more and 2000 mPasec or less, preferably 200 mPasec or more and 500 mPasec or less. The viscosity of the positive electrode solution 92 can be measured using an Ubbelt viscometer or the like, and the viscosity of the negative electrode solution 97 can be measured using a VT-06 manufactured by RION Corporation or the like.

[0098] When the cathode solution 92 has a high viscosity, the oxygen 12 generated in the cathode 93 easily enters the cathode solution 92, and the cathode solution 92 becomes a foaming state. Therefore, it is difficult to separate the oxygen 12 from the cathode solution 92 and discharge the separated oxygen 12 from the charging unit 78. Therefore, the charging efficiency of the charging unit 78 becomes low.

[0099] In contrast, when the cathode solution 92 has a low viscosity, the growth of bubbles of the oxygen gas 12 is promoted by the turbulence of the cathode solution 92. Therefore, the oxygen gas 12 is easily separated from the cathode solution 92, and the separated oxygen gas 12 is discharged from the charging unit 78. Therefore, the charging efficiency of the charging unit 78 is improved.

[0100] In the case where the negative electrode solution 97 has a low viscosity, when the negative electrode solution 97 acts on the negative electrode active material particles 41a in a reduced state, the resistance given to the negative electrode active material particles 41a in a reduced state becomes small. Therefore, it is difficult to peel off the negative electrode active material particles 41a in a reduced state from the negative electrode 98 and discharge the peeled negative electrode active material particles 41a in a reduced state from the charging unit 78. In addition, it is difficult to prevent the negative electrode active material particles 41a in a reduced state from settling due to gravity.

[0101] On the other hand, when the negative electrode solution 97 has a high viscosity, when the negative electrode solution 97 acts on the negative electrode active material particles 41a in a reduced state, the resistance given to the negative electrode active material particles 41a in a reduced state becomes large. Therefore, the negative electrode active material particles 41a in a reduced state are easily peeled off from the negative electrode 98, and the peeled negative electrode active material particles 41a in a reduced state are discharged from the charging unit 78. In addition, it is easy to prevent the negative electrode active material particles 41a in a reduced state from settling due to gravity.

[0102] In this way, when the second viscosity is made higher than the first viscosity to promote the peeling of the negative electrode active material particles 41a in the reduced state from the negative electrode 98, a movable portion for peeling the negative electrode active material particles 41a in the reduced state from the negative electrode 98 is not required. Thus, it is possible to provide a flow-type metal-air battery 1 that can peel the negative electrode active material particles 41a in the reduced state from the negative electrode 98 without consuming a large amount of power and has high durability.

[0103] The viscosity of the negative electrode solution 97 is adjusted by the type and / or concentration of the thickener 44 contained in the negative electrode solution 97. As the thickener 44, for example, an organic polymer material, an inorganic particle having a particle size of less than 1 μm, etc. are used. Examples of organic polymer materials are polyacrylic acid, carboxymethyl cellulose, sodium alginate, acrylic acid-alkyl methacrylate copolymer, etc. Examples of inorganic substances are calcium hydroxide, potassium silicate, etc. The viscosity of the negative electrode solution 97 can be adjusted by the concentration of the negative electrode active material particles 41b in an oxidized state having a particle size of less than 1 μm. In the case where the viscosity of the negative electrode solution 97 is adjusted by the concentration of the negative electrode active material particles 41b in an oxidized state, the thickener 44 is not contained in the negative electrode solution 97. In the case where the negative electrode active material ions 42 are zincate ions (Zn(OH) 4 2 _ ), if calcium hydroxide or potassium silicate is used as the thickener 44, calcium hydroxide or potassium silicate has a strong effect on zincate ions (Zn(OH) 4 2 _ ) has an influence on the solubility of the negative electrode active material ions 42, so the concentration of the negative electrode active material ions 42 in the negative electrode solution 97 can be set to a concentration suitable for the charging reaction.

[0104] In the case where the negative electrode solution 97 contains the thickener 44, the separator 101 does not allow the thickener 44 to pass through. Thus, the separator 101 inhibits the thickener 44 from moving from the negative electrode solution 97 to the positive electrode solution 92. Thus, the viscosity of the negative electrode solution 97 can be maintained higher than the viscosity of the positive electrode solution 92 for a long time. Thus, it becomes easier than ever to separate the oxygen 12 from the positive electrode solution 92 and discharge the separated oxygen 12 from the charging unit 78, and the negative electrode active material particles 41a in the reduced state can be peeled off from the negative electrode 98, and the state in which the peeled negative electrode active material particles 41a in the reduced state are easily discharged from the charging unit 78 can be maintained for a long time. Thus, the state in which the charging efficiency of the charging unit 78 is high can be maintained for a long time.

[0105] 1.11 Additional Components of Negative Electrode Solution The negative electrode solution 97 preferably contains at least one ion selected from the group consisting of metal elements of Group 13, metal elements of Group 14, and metal elements of Group 15, and further preferably contains at least one ion selected from the group consisting of indium and potassium contained in metal elements of Group 13, tin and lead contained in metal elements of Group 14, and antimony and bismuth contained in metal elements of Group 15, and particularly preferably contains indium ions. When the negative electrode solution 22 contains these ions, the adhesion between the negative electrode active material particles 41a in a reduced state and the negative electrode 98 can be reduced. Therefore, it is easier to peel off the negative electrode active material particles 41a in a reduced state from the negative electrode 98, and the peeled negative electrode active material particles 41a in a reduced state are discharged from the charging unit 78. When the negative electrode solution 97 contains ions of these metals, it is preferably contained at a concentration of 20 to 300 ppm, and more preferably contained at a concentration of 50 to 200 ppm. If the concentration of these metal ions is less than 20ppm, it may not be possible to sufficiently reduce the adhesion of the negative electrode active material particles 41a in the reduced state to the negative electrode 98. If the ion concentration of these metals exceeds 300ppm, these metals cannot be dissolved as ions and may precipitate in the solution. In particular, when the negative electrode solution 22 contains indium ions, the reason why the adhesion of the negative electrode active material particles 41a in the reduced state to the negative electrode 98 becomes low is that the ionization tendency of indium is smaller than the ionization tendency of zinc, and before zinc is generated from zinc ions, indium is generated from these indium ions to form a substrate composed of the generated indium. Therefore, it is not appropriate to include ions of gallium, germanium or arsenic having an ion tendency greater than that of zinc in the negative electrode solution 22.

[0106] 1.12 First Control Example of Current Value and Flow Rate Figure 4A This is a graph showing a first control example of the current value of the current flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery according to the first embodiment. Figure 4B This is a graph showing a first control example of the flow rate of the negative electrode solution in the second flow path of the second layer of the charging unit included in the flow-type metal-air battery of the first embodiment.

[0107] exist Figure 4A In the figure, the horizontal axis represents time and the vertical axis represents the current value. Figure 4B In the figure, the horizontal axis represents time and the vertical axis represents the flow rate.

[0108] In the first control example of the current value of the current flowing between the positive electrode 93 and the negative electrode 98 and the flow rate of the negative electrode solution 97 in the second flow path 96e of the second layer 96, as shown in FIG. Figure 4AAs shown in FIG. 1 , the control circuit 81 as the energization control unit maintains the current value at a constant current value I1. Therefore, the energization control unit keeps the current value at a constant current value I1 during the period T0 to T4.

[0109] In addition, if Figure 4B As shown, the control circuit 81, which is the control unit, periodically changes the flow rate between the first flow rate VL1 and the second flow rate VL2 which is larger than the first flow rate VL1. Therefore, the control unit makes the flow rate the first flow rate VL1 during the period T0 to T1, the second flow rate VL2 during the period T1 to T2, the first flow rate VL1 during the period T2 to T3, and the second flow rate VL2 during the period T3 to T4.

[0110] When the negative electrode solution 97 acts on the negative electrode active material particles 41a in a reduced state, the larger the particle size of the negative electrode active material particles 41a in a reduced state, the greater the resistance applied to the negative electrode active material particles 41a in a reduced state, and the greater the flow rate of the negative electrode solution 97, the greater the resistance applied to the negative electrode active material particles 41a in a reduced state. Therefore, in order to peel the negative electrode active material particles 41a in a reduced state from the negative electrode 98 and discharge the peeled negative electrode active material particles 41a in a reduced state from the charging unit 78, it is desirable to increase the flow rate of the negative electrode solution 98 when the particle size of the negative electrode active material particles 41a in a reduced state increases, so as to instantly bring a large resistance to the negative electrode active material particles 41a in a reduced state.

[0111] At this current value and this flow rate, Figure 4A as well as Figure 4B When the flow rate is set as shown, during the period T0 to T1 and the period T2 to T3 during charging when charging is performed and the flow rate is reduced to the first flow rate VL1, the resistance applied to the negative electrode active material particles 41a in the reduced state is reduced, and the negative electrode active material particles 41a in the reduced state grow. Therefore, the particle size of the negative electrode active material particles 41a in the reduced state increases.

[0112] Furthermore, during the period T1 to T2 and the period T3 to T4 when the flow velocity increases to the second flow velocity VL2 , the resistance applied to the negative electrode active material particles 41 a in the reduced state whose particle diameters increase increases.

[0113] This can promote the peeling of the negative electrode active material particles 41a in the reduced state from the negative electrode 98, and discharge the peeled negative electrode active material particles 41a in the reduced state from the charging unit 78. In addition, during the period T0 to T1 and the period T2 to T3, by setting the flow rate to the first flow rate VL1, the power consumed for flowing the negative electrode solution 97 can be reduced.

[0114] In this way, by controlling the current value and the flow rate, when the removal of the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is promoted, a movable portion for removing the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is not required. Thus, it is possible to provide a flow-type metal-air battery 1 that can remove the negative electrode active material particles 41a in a reduced state from the negative electrode 98 without consuming a large amount of power and has high durability.

[0115] Here, in Figure 4A In the example, a control method is shown in which the current value is maintained at a constant current value I1 during the period T0 to T4, but a control method may be adopted in which the current value is changed under the condition that it exceeds a predetermined current value during the period T0 to T4. Figure 4B In the figure, a control method is illustrated in which the flow rate is maintained at VL1 during the period T0 to T1 and the period T2 to T3, and the flow rate is maintained at VL2 during the period T1 to T2 and the period T3 to T4. However, a control method may also be adopted in which the flow rate is set to be greater than VL1 during the period T0 to T1 and the period T2 to T3, and the flow rate is set to be less than VL2 during the period T1 to T2 and the period T3 to T4.

[0116] In addition, Figure 4B In the figure, a control method is illustrated in which the lengths of the periods T0 to T1, T1 to T2, T2 to T3, and T3 to T4 are made the same. However, from the perspective of reducing the power consumed in order to make the negative electrode solution 97 flow, it is preferred that the lengths of the periods T1 to T2 and T3 to T4 are shorter than the lengths of the periods T0 to T1 and T2 to T3, and more preferably are 1 / 5 to 1 / 20 of the lengths of the periods T0 to T1 and T2 to T3.

[0117] 1.13 Second Control Example of Current Value and Flow Rate Figure 5A This is a graph showing a second control example of the current value flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment. Figure 5B This is a graph showing a second control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment.

[0118] exist Figure 5A In the figure, the horizontal axis represents time and the vertical axis represents the current value. Figure 5B In the figure, the horizontal axis represents time and the vertical axis represents the flow rate.

[0119] In the second control example of the current value of the current flowing between the positive electrode 93 and the negative electrode 98 and the flow rate of the negative electrode solution 97 in the second flow path 96e of the second layer 96, as shown in FIG. Figure 5AAs shown, the control circuit 81 as the power-on control unit causes the current value to change periodically between the first current value I1 and the second current value I2 which is smaller than the first current value I1. For this purpose, during the period T0 to T1, the power-on control unit causes the current value to be the first current value I1, during the period T1 to T2, the current value to be the second current value I2, during the period T2 to T3, the current value to be the first current value I1, and during the period T3 to T4, the current value to be the second current value I2. The power-on control unit preferably causes the second current value I2 to be smaller than the first current value I1, and more preferably alternately performs the following operations: setting the second current value I2 to 0, causing current to flow between the positive electrode 93 and the negative electrode 98; and reducing or stopping the current flowing between the positive electrode 93 and the negative electrode 98.

[0120] In addition, if Figure 5B As shown in FIG. 1 , the control circuit 81 serving as the control unit maintains the flow rate at a constant flow rate VL2. Therefore, the control unit maintains the flow rate at a constant flow rate VL2 during the period T0 to T4.

[0121] When the negative electrode solution 98 acts on the negative electrode active material particles 41a in a reduced state, the larger the particle size of the negative electrode active material particles 41a in a reduced state, the greater the resistance applied to the negative electrode active material particles 41a in a reduced state. Therefore, in order to peel off the negative electrode active material particles 41a in a reduced state from the negative electrode 98 and discharge the peeled negative electrode active material particles 41a in a reduced state from the charging unit 78, it is desirable to increase the particle size of the negative electrode active material particles 41a in a reduced state. However, during the period when the negative electrode active material particles 41a in a reduced state are peeled off from the negative electrode 98, it is desirable to stop the growth of the negative electrode active material particles 41a in a reduced state.

[0122] At this current value and this flow rate, Figure 5A as well as Figure 5B When the negative electrode active material particles 41a in the reduced state are set as shown, they grow in the period T0 to T1 and the period T2 to T3 when charging is performed at the first current value I1. Therefore, the particle size of the negative electrode active material particles 41a in the reduced state increases.

[0123] Furthermore, during the period T1 to T2 and the period T3 to T4 during which charging is performed at the second current value I2, due to the large resistance generated to the negative electrode active material particles 41a in the reduced state whose particle size increases, the negative electrode active material particles 41a in the reduced state are peeled off from the negative electrode 98. During the period T1 to T2 and the period T3 to T4, the growth of the negative electrode active material particles 41a in the reduced state is suppressed or stopped.

[0124] This promotes the separation of the negative electrode active material particles 41 a in a reduced state from the negative electrode 98 , and allows the separated negative electrode active material particles 41 a in a reduced state to be discharged from the charging unit 78 .

[0125] The first current value I1 may be greater than the current value Ih at which the hydrogen generation reaction starts, and the hydrogen generation reaction is a competitive reaction of the reduction reaction that generates the negative electrode active material particles 41a in the reduced state in the negative electrode 98. Therefore, the first current value I1 may also be a current value greater than the current value Ih at which hydrogen gas is generated on the negative electrode 98. The generated hydrogen gas increases the internal pressure inside the second flow path 96e of the second layer 96, and increases the flow rate of the negative electrode solution 97 in the second flow path 96e. Therefore, when hydrogen gas is generated on the negative electrode 98, when the negative electrode solution 97 acts on the negative electrode active material particles 41a in the reduced state, the resistance given to the negative electrode active material particles 41a in the reduced state becomes larger. As a result, it is possible to promote the peeling of the negative electrode active material particles 41a in the reduced state from the negative electrode 98, and discharge the peeled negative electrode active material particles 41a in the reduced state from the charging unit 78. In addition, the generated hydrogen gas adheres to the negative electrode active material particles 41a in the reduced state, and gives buoyancy to the negative electrode active material particles 41a in the reduced state. Thus, it is possible to promote the peeling of the negative electrode active material particles 41a in the reduced state from the negative electrode 98, and discharge the peeled negative electrode active material particles 41a in the reduced state from the charging unit 78. In addition, the generated hydrogen gas adheres to the negative electrode active material particles 41a in the reduced state and increases the apparent Stokes diameter of the negative electrode active material particles 41a in the reduced state. Therefore, when hydrogen gas is generated on the negative electrode 98, when the negative electrode solution 97 acts on the negative electrode active material particles 41a in the reduced state, the resistance given to the negative electrode active material particles 41a in the reduced state becomes larger. Thus, it is possible to promote the peeling of the negative electrode active material particles 41a in the reduced state from the negative electrode 98, and discharge the peeled negative electrode active material particles 41a in the reduced state from the charging unit 78.

[0126] In this way, by controlling the current value and the flow rate, when the removal of the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is promoted, a movable portion for removing the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is not required. Thus, it is possible to provide a flow-type metal-air battery 1 that can remove the negative electrode active material particles 41a in a reduced state from the negative electrode 98 without consuming a large amount of power and has high durability.

[0127] Here, in Figure 5A In the example, a control method is shown in which the current value is maintained at 11 during the period T0 to T1 and the period T2 to T3, and the current value is maintained at 12 during the period T1 to T2 and the period T3 to T4. However, a control method may be adopted in which the current value is maintained at more than 11 during the period T0 to T1 and the period T2 to T3, and the current value is maintained at less than 12 during the period T1 to T2 and the period T3 to T4. Figure 5BIn the example, a control method is shown in which the flow rate is maintained at a constant VL2 during the period T0 to T4. However, a control method may be adopted in which the flow rate is changed under the condition of exceeding a predetermined flow rate during the period T0 to T4.

[0128] In addition, Figure 5A In the invention, a control method is illustrated in which the lengths of the periods T0 to T1, T1 to T2, T2 to T3, and T3 to T4 are made the same. However, from the perspective of improving the efficiency of the charging reaction, it is preferred that the lengths of the periods T1 to T2 and T3 to T4 are shorter than those of the periods T0 to T1 and T2 to T3, and more preferably are 1 / 5 to 1 / 20 of the lengths of the periods T0 to T1 and T2 to T3.

[0129] 1.14 Third Control Example of Current Value and Flow Rate Fig. 6A This is a graph showing a third control example of the current value of the current flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment. Figure 6B This is a graph showing a third control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment.

[0130] exist Fig. 6A In the figure, the horizontal axis represents time and the vertical axis represents the current value. Figure 6B In the figure, the horizontal axis represents time and the vertical axis represents the flow rate.

[0131] In the third control example of the current value of the current flowing between the positive electrode 93 and the negative electrode 98 and the flow rate of the negative electrode solution 97 in the second flow path 96e of the second layer 96, as shown in FIG. Fig. 6A As shown, the control circuit 81 as the power-on control unit causes the current value to change periodically between the first current value I1 and the second current value I2 which is smaller than the first current value I1. To this end, the power-on control unit causes the current value to be the first current value I1 during the period T0 to T1, the second current value I2 during the period T1 to T2, the first current value I1 during the period T2 to T3, and the second current value I2 during the period T3 to T4. The power-on control unit preferably causes the second current value I2 to be smaller than the first current value I1, and more preferably alternately performs the following operations: setting the second current value I2 to 0, causing current to flow between the positive electrode 93 and the negative electrode 98; and reducing or stopping the current flowing between the positive electrode 93 and the negative electrode 98.

[0132] In addition, if Figure 6BAs shown, the control circuit 81, which is the control unit, periodically changes the flow rate between the first flow rate VL1 and the second flow rate VL2 which is larger than the first flow rate VL1. Therefore, the control unit makes the flow rate the first flow rate VL1 during the period T0 to T1, the second flow rate VL2 during the period T1 to T2, the first flow rate VL1 during the period T2 to T3, and the second flow rate VL2 during the period T3 to T4.

[0133] When the negative electrode solution 98 acts on the negative electrode active material particles 41a in a reduced state, the larger the particle size of the negative electrode active material particles 41a in a reduced state, the greater the resistance applied to the negative electrode active material particles 41a in a reduced state, and the greater the flow rate of the negative electrode solution 98, the greater the resistance applied to the negative electrode active material particles 41a in a reduced state. Therefore, in order to peel the negative electrode active material particles 41a in a reduced state from the negative electrode 98 and discharge the peeled negative electrode active material particles 41a in a reduced state from the charging unit 78, it is desirable to increase the flow rate of the negative electrode solution 98 at the time when the particle size of the negative electrode active material particles 41a in a reduced state becomes larger, and to instantly give a large resistance to the negative electrode active material particles 41a in a reduced state. However, during the period when the negative electrode active material particles 41a in a reduced state are peeled from the negative electrode 98, it is desirable to stop the growth of the negative electrode active material particles 41a in a reduced state. Therefore, the period T0-T1 and the period T2-T3 during which the battery is charged at the first current value I1 include the period T0-T1 and the period T2-T3 during which the flow rate is the first flow rate VL1. In addition, the period T1-T2 and the period T3-T4 during which the battery is charged at the second current value I2 include the period T1-T2 and the period T3-T4 during which the flow rate is the second flow rate VL2.

[0134] At this current value and this flow rate, Fig. 6A and Figure 6B When the current is charged at the first current value I1 and the flow rate is reduced to the first flow rate VL1 during the period T0-T1 and the period T2-T3, the resistance applied to the negative electrode active material particles 41a in the reduced state is reduced, and the negative electrode active material particles 41a in the reduced state grow. Therefore, the particle size of the negative electrode active material particles 41a in the reduced state increases.

[0135] Furthermore, during the period T1-T2 and the period T3-T4 when the flow velocity increases to the second flow velocity VL2, the resistance applied to the negative electrode active material particles 41a in the reduced state with increased particle size increases. During the period T1-T2 and the period T3-T4, the growth of the negative electrode active material particles 41a in the reduced state is suppressed or stopped.

[0136] This promotes the separation of the negative electrode active material particles 41 a in a reduced state from the negative electrode 98 , and allows the separated negative electrode active material particles 41 a in a reduced state to be discharged from the charging unit 78 . Furthermore, in the period T1 to T2 and the period T2 to T3, by setting the flow velocity to the first flow velocity VL1, it is possible to reduce the power consumed for flowing the negative electrode solution 97.

[0137] In this way, by controlling the current value and the flow rate, when the removal of the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is promoted, a movable portion for removing the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is not required. Thus, it is possible to provide a flow-type metal-air battery 1 that can remove the negative electrode active material particles 41a in a reduced state from the negative electrode 98 without consuming a large amount of power and has high durability.

[0138] Here, in Fig. 6A In the example, a control method is shown in which the current value is maintained at I1 during the period T0 to T1 and the period T2 to T3, and the current value is maintained at I2 during the period T1 to T2 and the period T3 to T4. However, a control method may be adopted in which the current value is set to be greater than I1 during the period T0 to T1 and the period T2 to T3, and the current value is set to be less than I2 during the period T1 to T2 and the period T3 to T4. Figure 6B In the figure, a control method is illustrated in which the flow rate is maintained at VL1 during the period T0 to T1 and the period T2 to T3, and the flow rate is maintained at VL2 during the period T1 to T2 and the period T3 to T4. However, a control method may also be adopted in which the flow rate is set to be greater than VL1 during the period T0 to T1 and the period T2 to T3, and the flow rate is set to be less than VL2 during the period T1 to T2 and the period T3 to T4.

[0139] In addition, Fig. 6A and Figure 6B In the figure, a control method is illustrated in which the lengths of the periods T0 to T1, T1 to T2, T2 to T3, and T3 to T4 are made the same. However, from the perspective of reducing the power consumed in making the negative electrode solution 97 flow and improving the efficiency of the charging reaction, it is preferred that the lengths of the periods T1 to T2 and T3 to T4 are shorter than the lengths of the periods T0 to T1 and T2 to T3, and more preferably are 1 / 5 to 1 / 20 of the lengths of the periods T0 to T1 and T2 to T3.

[0140] 1.15 Fourth Control Example of Current Value and Flow Rate Figure 7 This is a graph showing a fourth control example of the current value of the current flowing between the positive electrode of the charging unit and the negative electrode of the charging unit included in the flowing metal-air battery of the first embodiment.

[0141] exist Figure 7 In the figure, the horizontal axis represents time and the vertical axis represents the current value.

[0142] Hereinafter, the fourth control example of the current value flowing between the positive electrode 93 and the negative electrode 98 and the flow rate of the negative electrode solution 97 in the second flow path 96e of the second layer 96 will be described in terms of differences from the third control example of the current and the flow rate.

[0143] In the fourth control example of the current and the flow rate, the same as the third control example of the current and the flow rate, as shown in FIG. Figure 7 As shown, the control circuit 81 serving as the energization control unit periodically changes the current value between a first current value I1 and a second current value I2 which is smaller than the first current value I1.

[0144] However, in the fourth control example of the current and the flow rate, unlike the third control example of the current and the flow rate, Figure 7 As shown, the sign of the first current value I1 is opposite to the sign of the second current value I2. Therefore, the direction of the current flowing between the positive electrode 93 and the negative electrode 98 during the period T0 to T1 and the period T2 to T3 is opposite to the direction of the current flowing between the positive electrode 93 and the negative electrode 98 during the period T1 to T2 and the period T3 to T4. The sign of the first current value I1 is positive, and the sign of the second current value I2 is negative. Therefore, during the period T0 to T1 and the period T2 to T3, a reduction reaction to metallic zinc occurs on the negative electrode 98, and during the period T1 to T2 and the period T3 to T4, an oxidation reaction to zinc ions occurs on the negative electrode 98. The oxidation reaction to zinc ions occurs at the interface between the negative electrode 98 and the negative electrode active material particles 41a in a reduced state. Therefore, the negative electrode active material particles 41a in a reduced state are dissolved at the interface by the oxidation reaction to zinc ions. As a result, the adhesion between the negative electrode active material particles 41a in a reduced state and the negative electrode 98 can be reduced. This promotes the separation of the negative electrode active material particles 41 a in a reduced state from the negative electrode 98 , and allows the separated negative electrode active material particles 41 a in a reduced state to be discharged from the charging unit 78 .

[0145] In this way, by controlling the current value and the flow rate, when the removal of the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is promoted, a movable portion for removing the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is not required. Thus, it is possible to provide a flow-type metal-air battery 1 that can remove the negative electrode active material particles 41a in a reduced state from the negative electrode 98 without consuming a large amount of power and has high durability.

[0146] 1.16 Fifth Control Example of Current Value and Flow Rate Figure 8 This is a graph showing a fifth control example of the flow rate of the negative electrode solution in the second flow path of the charging unit included in the flow-type metal-air battery of the first embodiment.

[0147] exist Figure 8 In the figure, the horizontal axis represents time and the vertical axis represents the flow rate.

[0148] Hereinafter, the fifth control example of the current value flowing between the positive electrode 93 and the negative electrode 98 and the flow rate of the negative electrode solution 97 in the second flow path 96e of the second layer 96 will be described in terms of differences from the third control example of the current and the flow rate.

[0149] In the fifth control example, the current and the flow rate are the same as in the third control example, as shown in FIG. Figure 8 As shown, a control circuit 81 serving as a control unit periodically changes the flow velocity between a first flow velocity VL1 and a second flow velocity VL2 that is greater than the first flow velocity VL1.

[0150] However, in the fifth control example, unlike the third control example of the current and the flow rate, Figure 8 As shown, the first flow rate VL1 is 0. Thus, the power consumed by the negative electrode solution 97 flowing during the period T0 to T1 and the period T2 to T3 can be eliminated. In addition, the supply of the negative electrode active material ions 42 to the negative electrode 98 can be limited during the period T0 to T1 and the period T2 to T3. Thus, the growth of the negative electrode active material particles 41a in the reduced state with a large volume of dendrites on the negative electrode 98 can be promoted. Thus, when the negative electrode solution 97 acts on the negative electrode active material particles 41a in the reduced state, the resistance applied to the negative electrode active material particles 41a in the reduced state can be increased.

[0151] In this way, by controlling the current value and the flow rate, when the removal of the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is promoted, a movable portion for removing the negative electrode active material particles 41a in a reduced state from the negative electrode 98 is not required. Thus, it is possible to provide a flow-type metal-air battery 1 that can remove the negative electrode active material particles 41a in a reduced state from the negative electrode 98 without consuming a large amount of power and has high durability.

[0152] 1.17 Modification Fig. 9 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a first modification of the first embodiment.

[0153] In a first embodiment, if Figure 3 As shown, the positive electrode chamber is formed by three positive electrode chamber components including the first layer 91 , the current-carrying plate 94 and the gasket 95 , and the negative electrode chamber is formed by three negative electrode chamber components including the second layer 96 , the current-carrying plate 99 and the gasket 100 .

[0154] In contrast, in the first modification of the first embodiment, Fig. 9As shown, a positive electrode chamber component 111 formed by integrating the first layer 91, the current-carrying plate 94 and the gasket 95 constitutes a positive electrode chamber, and a negative electrode chamber component 112 formed by integrating the second layer 96, the current-carrying plate 99 and the gasket 100 constitutes a negative electrode chamber.

[0155] Fig.10 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a second modification of the first embodiment.

[0156] In a first embodiment, if Figure 3 As shown, the negative electrode 98 and the current-carrying plate 99 are formed as separate bodies.

[0157] In contrast, in the second variation of the first embodiment, Fig.10 As shown, the current-carrying plate 99 also serves as the negative electrode 98, and the current-carrying plate 99 and the negative electrode 98 are integrally formed, and the negative electrode 98 and the current-carrying plate 99 are integrally formed into a single body. Thus, the number of components constituting the charging unit 78 can be reduced. In addition, the number of steps required to assemble the charging unit 78 can be reduced. In addition, the lead time required to assemble the charging unit 78 can be shortened. Thus, the cost of the charging unit 78 can be reduced.

[0158] Fig.11 This is a cross-sectional view schematically showing a charging unit included in a liquid-flow type metal-air battery according to a third modification of the first embodiment.

[0159] In a first embodiment, if Figure 3 As shown, the second layer 96, the negative electrode 98 and the current-carrying plate 99 are each formed as a separate body.

[0160] In contrast, in the third variation of the first embodiment, Fig.11 As shown, the power-carrying plate 99 also serves as the second layer 96 and the negative electrode 98, and the power-carrying plate 99 is integrally formed with the second layer 96 and the negative electrode 98, and the second layer 96, the negative electrode 98 and the power-carrying plate 99 are formed as an integral body. Thus, the number of components constituting the charging unit 78 can be reduced. In addition, the number of processes required to assemble the charging unit 78 can be reduced. In addition, the lead time required to assemble the charging unit 78 can be shortened. Thus, the cost of the charging unit 78 can be reduced. In addition, there is no need for a gasket 100 that liquid-tightly seals the second layer 96 and the negative electrode 98 and the power-carrying plate 99. Thus, leakage of the negative electrode liquid 97 from the negative electrode chamber can be suppressed. Thus, the long-term stability and reliability of the charging unit 78 can be improved.

[0161] Fig.12 This is a cross-sectional view schematically showing a charging unit included in a flow-type metal-air battery according to a fourth modification of the first embodiment.

[0162] In a fourth variation of the first embodiment, Fig.12 As shown, the negative electrode 98 includes a first portion 121 composed of a first raw material and a second portion 122 composed of a second raw material. The hydrogen overvoltage of the second raw material is lower than the hydrogen overvoltage of the first raw material. As a result, hydrogen gas is easily generated on the second portion 122. As described above, the generated hydrogen gas promotes the stripping of the negative electrode active material particles 41a in a reduced state from the negative electrode 98, and the stripped negative electrode active material particles 41a in a reduced state are discharged from the charging unit 78. The first raw material, for example, includes at least one selected from the group consisting of carbon, copper, and magnesium. The second raw material, for example, includes nickel.

[0163] 1.18 Charging experiment (charging experiment 1) As Example 1, make Figure 3 The charging unit 78 shown is used to carry out a charging experiment.

[0164] Carbon was used for the negative electrode 98. The size of the portion of the negative electrode 98 immersed in the negative electrode solution 97 was 10 mm×80 mm.

[0165] A nickel porous body (Celmet (registered trademark) manufactured by Sumitomo Electric Industries, Ltd.) was used as the positive electrode 93. The size of the portion of the positive electrode 93 immersed in the positive electrode solution 92 was 10 mm×80 mm.

[0166] The structure other than the negative electrode 98 and the positive electrode 93 is as follows. Separator 101: "Separator in the form of a sheet with a thickness of 0.1 mm and a size of 20 mm x 110 mm" manufactured by Nippon Shokubai Co., Ltd. Positive electrode solution 92: Zn saturated KOH aqueous solution "KOH 29.2%, zinc oxide 4%" Negative electrode solution 97: Zn saturated KOH aqueous solution "KOH 29.2%, zinc oxide 4%, thickener 1%" Here, the viscosity of the negative electrode solution was evaluated using VT-06 manufactured by RION Corporation and found to be 100 mPasec.

[0167] In the charging unit of Comparative Example 1, the structure other than the negative electrode solution 97 is the same as that of the charging unit 78 of Example 1. The negative electrode solution 97 of Comparative Example 1 is as follows: Negative electrode solution 97: Zn saturated KOH aqueous solution "KOH 29.2%, zinc oxide 4%" Here, the viscosity of the negative electrode solution was measured with an Ubbel viscometer, and the result was 2 mPasec.

[0168] The positive electrode solution 92 and the negative electrode solution 97 were passed through the charging unit 78 of Example 1 and the charging unit of the comparative example to conduct a charging experiment. In the charging experiment, a current density of 100 mA / cm 2(unit projected area of ​​negative electrode 98) constant current charging. The measurement was performed using a battery tester (manufactured by Kikusui Electronics Industry Co., Ltd.: SPEC20526-PFX2011S). In the charging experiment, the weight of the negative electrode active material (metal zinc) particles 41a in the reduced state peeled off from the negative electrode 98 and discharged from the charging unit 78 of Example 1 and the charging unit of the comparative example was measured, and the zinc recovery rate relative to the input power was calculated. The calculation results are shown in Table 1. Zinc recovery rate (%) = weight of discharged zinc (g) × 0.82 (Ah / g: specific capacity of zinc) / input power (Ah) × 100

[0169] Table 1 Example 1 Example 2 Example 3 <![CDATA[Zinc recovery rate under a current density of 100 mA / cm 2 > 68 94 0

[0170] As shown in Table 1, when the negative electrode solution 97 has a low viscosity (Comparative Example 1), the negative electrode active material (metal zinc) particles 41a in a reduced state are not discharged from the charging unit. This is because when the negative electrode solution 97 acts on the negative electrode active material (metal zinc) particles 41a in a reduced state, the resistance given to the negative electrode active material (metal zinc) particles 41a in a reduced state becomes small.

[0171] In contrast, when the negative electrode solution 97 has a high viscosity (Example 1), the negative electrode active material (metal zinc) particles 41a in a reduced state are easily discharged from the charging unit 78. This is because when the negative electrode solution 97 acts on the negative electrode active material (metal zinc) particles 41a in a reduced state, the resistance applied to the negative electrode active material (metal zinc) particles 41a in a reduced state becomes large.

[0172] (Charging Experiment 2) As Example 2, a charging experiment was conducted using a charging unit 78 having the same configuration as that of the charging unit 78 of Example 1 except for the negative electrode solution 97. The negative electrode solution 97 of Example 2 was as follows. Negative solution 97: Zn saturated KOH aqueous solution "KOH 29.2%, zinc oxide 4%, thickener 1%, indium hydroxide 0.01%" Here, the viscosity of the negative electrode solution was evaluated using VT-06 manufactured by RION Corporation and the result was 100 mPasec.

[0173] As shown in Table 1, when the negative electrode solution 97 has a high viscosity and contains an additional component (indium ion), the recovery rate of the negative electrode active material (metal zinc) particles 41a in a reduced state discharged from the charging unit 78 is improved. This is because the adhesion of the negative electrode active material (metal zinc) particles 41a in a reduced state to the negative electrode 98 is reduced. Therefore, when the negative electrode solution 97 has a high viscosity and contains an additional component (indium ion), the negative electrode active material (zinc) particles 41a in a reduced state are peeled off from the negative electrode 98, and it becomes easier to discharge the peeled negative electrode active material (metal zinc) particles 41a in a reduced state from the charging unit 78.

[0174] (Charging experiment 3) As Example 3, a charging experiment was conducted using the same charging unit 78 as that of Example 2. The positive electrode solution 92 and the negative electrode solution 97 were also the same as those of Example 2. Specifically, it was as follows. Positive electrode solution 92: Zn saturated KOH aqueous solution "KOH 29.2%, zinc oxide 4%" Negative electrode solution 97: Zn saturated KOH aqueous solution "KOH 29.2%, zinc oxide 4%, thickener 1%, indium hydroxide 0.01%" Here, the viscosity of the negative electrode solution was evaluated using VT-06 manufactured by RION Corporation and the result was 100 mPasec.

[0175] In charging experiment 3, the current density (unit projected area of ​​the negative electrode 98) was changed to perform constant current charging. In the charging experiment, the weight of the negative electrode active material (metal zinc) particles 41a in the reduced state peeled off from the negative electrode 98 and discharged from the charging unit 78 was measured, and the zinc recovery rate relative to the input electricity was calculated. The calculation results are shown in Table 2.

[0176] Table 2

[0177] As shown in Table 2, there is a preferred current density (unit projected area of ​​the negative electrode 98) range that can improve the recovery rate of the negative electrode active material (metal zinc) particles 41a in the reduced state discharged from the charging unit. When the current density (unit projected area of ​​the negative electrode 98) is low (for example, 30 mA / cm 2 or 50mA / cm 2 ), it is difficult to peel off the negative electrode active material (metal zinc) particles 41a in a reduced state from the negative electrode 98. This is because it is easy to grow dense negative electrode active material (metal zinc) particles 41a in a reduced state on the negative electrode 98, and when the negative electrode solution 97 acts on the negative electrode active material (metal zinc) particles 41a in a reduced state, the resistance brought to the negative electrode active material (metal zinc) particles 41a in a reduced state becomes smaller.

[0178] On the other hand, when the current density (unit projected area of ​​the negative electrode 98) is high (e.g., 150 m / cm 2 ), it is easy to peel off the negative electrode active material (metal zinc) particles 41a in a reduced state from the negative electrode 98, but the zinc recovery rate is reduced due to the competing reaction of the reduction reaction that produces the negative electrode active material (metal zinc) particles 41a in a reduced state, namely the hydrogen generation reaction.

[0179] 1.19 Charging Unit Stack Fig.13 This is a cross-sectional view schematically showing a charging unit stack that can replace the charging unit included in the flow-type metal-air battery of the first embodiment.

[0180] Fig.13 The charging cell stack 131 shown has a plurality of charging cells 78 .

[0181] A plurality of charging units 78 are stacked to form a battery pack. Thus, the power that can be charged by the charging unit stack 131 can be made larger than the power that can be charged by one charging unit 78 .

[0182] The plurality of charging units 78 include two adjacent charging units 78. The main surface 94p of the power-carrying plate 94 of one of the two adjacent charging units 78 is in surface contact with the main surface 99p of the power-carrying plate 99 of the other of the two adjacent charging units 78. Thus, the power-carrying plate 94 and the power-carrying plate 99 are electrically connected to each other, forming a bipolar plate 141 having the functions of a positive power-carrying plate and a negative power-carrying plate. Thus, the plurality of charging units 78 are electrically connected in series.

[0183] A positive electrode chamber is formed between the bipolar plate 141 and the separator 101 of the charging unit 78 on one side. A negative electrode chamber is formed between the bipolar plate 141 and the separator 101 of the charging unit 78 on the other side. A first flow path 91e is formed in the positive electrode chamber. A second flow path 96e is formed in the negative electrode chamber. The positive electrode solution 92 is flowed in parallel into the plurality of first flow paths 91e formed. The negative electrode solution 97 is flowed in parallel into the plurality of second flow paths 96e formed.

[0184] 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 produces the same function and effect, or a configuration that can achieve the same purpose.

Claims

1. A charging unit for a mobile metal-air battery, characterized in that: have: a first layer having a first flow path formed therein; a positive electrode facing the first flow path; a second layer having a second flow path formed therein; a cathode facing the second flow path; a separator separating the first flow path and the second flow path from each other; A cathode solution having a first viscosity flowing in the first flow path; and A negative electrode solution having a second viscosity higher than the first viscosity flows in the second flow path.

2. The charging unit for a mobile metal-air battery according to claim 1, wherein: Oxygen gas is generated by the reaction in the positive electrode, and negative electrode active material particles are generated by the reaction in the negative electrode.

3. The charging unit for a mobile metal-air battery according to claim 1, wherein: The cathode solution comprises a first electrolyte, The negative electrode solution includes a second electrolyte and negative electrode active material ions dissolved in the second electrolyte.

4. The charging unit for a mobile metal-air battery according to claim 3, characterized in that: The negative electrode solution contains a thickener.

5. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: The negative electrode solution contains at least one ion selected from the group consisting of Group 13 metal elements, Group 14 metal elements, and Group 15 metal elements.

6. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: The negative electrode solution contains zinc ions and indium ions.

7. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: The separator is an anion exchange membrane, a hydrogel membrane, or a membrane including a plurality of inorganic ion conductor particles and a resin impregnated in grain boundaries of the plurality of inorganic ion conductor particles.

8. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: The positive electrode comprises nickel, The negative electrode includes at least one selected from the group consisting of carbon, copper, and magnesium.

9. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: A current-carrying plate integrally formed with the negative electrode is provided.

10. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: A current-carrying plate integrally formed with the negative electrode and the second layer is provided.

11. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: The first flow path includes a portion for guiding the cathode liquid in a vertical direction. The flow-type metal-air battery charging unit includes a mechanism for generating a flow of the cathode solution, wherein the flow direction of the cathode solution in the portion is from a vertically downward direction to a vertically upward direction.

12. The charging unit for a mobile metal-air battery according to any one of claims 1 to 4, characterized in that: The second flow path includes a portion for guiding the negative electrode liquid in a vertical direction. The flow-type metal-air battery charging unit includes a mechanism for generating a flow of the negative electrode solution, wherein the flow direction of the negative electrode solution in the portion is from a vertically downward direction to a vertically upward direction.

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