WO2015115479A1

WO2015115479A1 - Metal air cell

Info

Publication number: WO2015115479A1
Application number: PCT/JP2015/052355
Authority: WO
Inventors: 宏隆水畑; 吉田　章人; 将史村岡; 友春新井
Original assignee: シャープ株式会社
Priority date: 2014-01-29
Filing date: 2015-01-28
Publication date: 2015-08-06
Also published as: JPWO2015115479A1; JP6333863B2

Abstract

　This metal air cell is characterized in being provided with: an electrolyte tank accommodating an electrolyte; a metal electrode provided in the electrolyte tank, the metal electrode having an electrode active material and functioning as an anode; an air electrode functioning as a cathode; a first measurement unit for measuring the electrolyte and/or a second measurement unit for measuring the discharge current of the metal air cell; and a communication unit for communicating cell information based on the result of measurement by the first measurement unit and/or the second measurement unit.

Description

Metal air battery

The present invention relates to a metal-air battery.

Since metal-air batteries have high energy density, they are attracting attention as next-generation batteries. A metal-air battery generates electricity by using a metal electrode containing an electrode active material and being disposed in an electrolyte as an anode and an air electrode as a cathode.
As a typical metal-air battery, a zinc-air battery using metal zinc as an electrode active material can be mentioned. In a zinc-air battery, it is considered that an electrode reaction of the following chemical formula 1 proceeds at the cathode.
(Chemical formula 1): O ₂ + 2H ₂ O + 4e ⁻ → 4OH ⁻
Further, it is considered that an electrode reaction as represented by the following chemical formula 2 proceeds at the anode.
(Chemical formula 2): Zn + 4OH ⁻ → Zn (OH) ₄ ²⁻ + 2e ⁻

When such an electrode reaction proceeds, the electrode active material of the metal electrode is consumed and gradually decreases. In addition, the concentration of metal-containing ions (Zn (OH) ₄ ²⁻ ) in the electrolyte solution gradually increases, and when saturation is reached, a reaction such as the following chemical formula 3 or chemical formula 4 proceeds and uniform nucleation or Heterogeneous nucleation occurs. Then, as the produced nucleus grows, a metal oxide or metal hydroxide precipitate is deposited and accumulated in the electrolytic solution tank as a used active material.
(Chemical formula 3): Zn (OH) ₄ ²⁻ → ZnO + 2OH ⁻ + H ₂ O
(Chemical formula 4): Zn (OH) ₄ ²⁻ → Zn (OH) ₂ + 2OH ⁻
This precipitate may be deposited as fine particles in the electrolyte solution or may be deposited as a passive state on the surface of the metal electrode.
When the used active material in the form of fine particles accumulates in the electrolytic solution tank, the ionic conductivity between the anode and the cathode may decrease and the output of the metal-air battery may decrease. In addition, the used active material may be deposited as a passive state on the surface of the metal electrode to inhibit the anode reaction. For this reason, it is necessary to discharge the spent active material in the form of fine particles from the electrolytic solution tank and to replace the metal electrode with the passivated metal with a new metal electrode.

Moreover, since the amount of the electrode active material contained in the metal electrode decreases as the electrode reaction proceeds, it is necessary to replace the used metal electrode with a reduced amount of the electrode active material with a new metal electrode.
Furthermore, since water contained in the electrolytic solution is lost due to battery reaction or evaporation at the air electrode, it is necessary to replenish the electrolytic solution tank with water or electrolytic solution.
As described above, in the metal-air battery, it is necessary to perform maintenance such as discharge of the used active material, replacement of the metal electrode, and replenishment of water or electrolyte at an appropriate time. However, it is difficult for the user to grasp this appropriate time.

As a metal-air battery equipped with means for notifying the user of this appropriate time, a metal-air battery that notifies the user of the replacement time of the metal electrode based on the battery capacity detected by a battery capacity detection circuit or the like is known (for example, Patent Document 1).

JP 2004-362869 A

However, in the conventional metal-air battery, in order to notify the user based on the battery capacity detected by the battery capacity detection circuit or the like, it is not possible to notify the appropriate time for discharging the used active material and supplying water or electrolyte. difficult.
In addition, it may be necessary to replace the metal electrode due to a decrease in the amount of the electrode active material, and it may be necessary to replace the metal electrode because the used active material adheres to the surface of the metal electrode as a passive state. It is difficult to notify the appropriate replacement time of the metal electrode based on the battery capacity detected by the battery capacity detection circuit or the like.
This invention is made | formed in view of such a situation, and provides the metal air battery which can notify a user etc. of the suitable time which performs a maintenance of a metal air battery.

The present invention relates to an electrolytic solution tank that contains an electrolytic solution, a metal electrode that is provided in the electrolytic solution tank and has an electrode active material and serves as an anode, an air electrode that serves as a cathode, and the electrolytic solution to be measured A metal-air battery comprising: a first measurement unit that includes: a notification unit that notifies battery information based on a measurement result of the first measurement unit.

According to the present invention, a metal tank includes an electrolyte tank that contains an electrolyte, a metal electrode that is provided in the electrolyte tank and has an electrode active material and serves as an anode, and an air electrode that serves as a cathode. The anode reaction can proceed at the electrode, and the cathode reaction can proceed at the air electrode. Thereby, an electromotive force can be generated between the metal electrode and the air electrode.
According to this invention, since the 1st measurement part which makes electrolyte solution a measurement object is provided, physical property values, such as pH value, electroconductivity, viscosity, or density of electrolyte solution, can be measured by a 1st measurement part.
According to the present invention, since the notification unit that notifies the battery information based on the measurement result of the first measurement unit is provided, the information indicating the dischargeable time calculated from the measurement result of the first measurement unit, the ion concentration of the electrolytic solution Battery information such as information that represents information and information that represents the time when the electrolytic solution or water is supplied to the electrolytic solution tank can be notified to a user or the like. Moreover, since this battery information is calculated from the measurement result for the electrolytic solution, more accurate information can be notified to the user or the like.
As a result, the user or the like can know an appropriate time for performing maintenance, and can perform maintenance at an appropriate time.

It is a schematic sectional drawing of the metal air battery of one Embodiment of this invention. It is a graph which shows the relationship between the discharge capacity | capacitance measured in the discharge experiment 1, and the electrical conductivity of electrolyte solution. ₃ is a graph showing changes in Zn (OH) ₄ ^2- ion concentration in discharge experiment 1. FIG. 4 is a graph showing changes in OH ⁻ ion concentration in discharge experiment 1. FIG. 6 is a graph showing the relationship between the Zn (OH) ₄ ^2- ion concentration measured in the discharge experiment 3 and the conductivity of the electrolytic solution.

An electrolytic solution tank that contains an electrolytic solution, a metal electrode that is provided in the electrolytic solution tank and has an electrode active material and serves as an anode, an air electrode that serves as a cathode, and a first electrode that uses the electrolytic solution as a measurement target A measurement unit and / or a second measurement unit for measuring a discharge current of the metal-air battery; and a notification unit for notifying battery information based on a measurement result of the first measurement unit and / or the second measurement unit. It is characterized by providing.

In the metal-air battery of the present invention, the first measurement unit is a measurement unit that measures at least a pH value, conductivity, viscosity, or density related to the electrolytic solution, and the battery information includes information indicating a dischargeable time, the electrolysis It is preferable that the information represents the ion concentration of the liquid or the information indicating the time when the electrolytic solution or water is supplied to the electrolytic solution tank.
According to such a configuration, the user or the like can know the dischargeable time, the ion concentration of the electrolyte, or the time to replenish the electrolyte or water in the electrolyte bath, and can perform maintenance at an appropriate time. .
In the metal-air battery of the present invention, it is preferable that the first measurement unit is a measurement unit that measures the electrical conductivity of the electrolytic solution, and the battery information is information representing a dischargeable time.
According to such a configuration, the user or the like can know the dischargeable time, and the metal electrode can be replaced at an appropriate time.

In the metal-air battery of the present invention, the notification unit is a notification unit that notifies battery information based on a measurement result of the first measurement unit and / or the second measurement unit, and the battery information is included in the metal electrode. Information representing the remaining amount of the electrode active material, information representing the amount of precipitate generated from the electrode active material, or information representing the discharge timing of the deposit is preferable.
According to such a configuration, the remaining amount of the electrode active material contained in the metal electrode, the amount of precipitate generated from the electrode active material, or the discharge timing of the precipitate can be known, and maintenance is performed at an appropriate time. be able to.
In the metal-air battery of the present invention, the notification unit is preferably a notification unit that notifies battery information to a remote place using a data communication line.
According to such a configuration, a remote user or administrator can know the battery information, and can monitor the metal-air battery. This enables, for example, a remote manager or management company to manage and maintain the metal-air battery. In addition, a remote administrator or management company can simultaneously monitor a plurality of metal-air batteries.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations shown in the drawings and the following description are merely examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

Configuration of Metal-Air Battery FIG. 1 is a schematic sectional view of a metal-air battery according to this embodiment.
The metal-air battery 30 according to the present embodiment includes an electrolytic solution tank 2 that contains an electrolytic solution 3, a metal electrode 5 that is provided in the electrolytic solution tank 2 and has an electrode active material and serves as an anode, and air that serves as a cathode. It is provided with the pole 9, the 1st measurement part 24 which makes the electrolyte solution 3 measurement object, and the notification part 27 which notifies the battery information based on the measurement result of the 1st measurement part 24, It is characterized by the above-mentioned.
Hereinafter, the metal-air battery 30 of this embodiment will be described.

1. Metal-air battery The metal-air battery 30 of the present embodiment is a battery in which the metal electrode 5 containing a metal serving as an electrode active material is a negative electrode (anode) and the air electrode 9 is a positive electrode (cathode). For example, a zinc air battery, a lithium air battery, a sodium air battery, a calcium air battery, a magnesium air battery, an aluminum air battery, and an iron air battery. Further, the metal-air battery 30 of the present embodiment may be a primary battery.
The metal-air battery 30 has a metal-air battery body composed of the electrolytic solution tank 2, the air electrode 9 and the like, and a structure that can be attached to and detached from the metal-air battery body. You may comprise from an electrode holder.

2. Cell The cell is a structural unit of the metal-air battery 30, and has an electrode pair that is provided in the electrolytic solution tank 2 (electrolytic solution chamber) and includes a metal electrode 5 serving as an anode and an air electrode 9 serving as a cathode. The cell may have, for example, an electrode pair in which one air electrode 9 and one metal electrode 5 are provided so as to sandwich the

electrolytic solution

3, and 2 cells like the metal-air battery 30 shown in FIG. One air electrode 9 may have an electrode pair provided so as to sandwich one metal electrode 5.
The cell may include an electrolytic solution tank 2 or an electrolytic solution chamber, a metal electrode 5 provided in the electrolytic solution tank 2 or the electrolytic solution chamber and serving as an anode, and an air electrode 9 serving as a cathode.

3. Cell assembly The cell assembly has a stack structure in which a plurality of cells are stacked. In the cell assembly, a plurality of cells may be provided in one electrolytic solution tank 2, and each cell may have the electrolytic solution tank 2 or the electrolytic solution chamber. The number of cells constituting the cell assembly is not particularly limited, and the number of cells may be determined according to the required power generation capacity.
In addition, when a plurality of cells constituting the cell assembly each have the electrolytic solution tank 2, the electrolytic solution tank 2 included in each cell may be provided in a common housing 1, and each cell has the housing 1. The casing 1 may be provided with an electrolytic solution tank 2.
Note that two or three cells may be provided in one casing 1, and a plurality of such casings 1 may be combined to form a cell aggregate.
The electrode pairs of a plurality of cells included in the cell assembly may be connected in series or in parallel.

4). Electrolytic Solution, Electrolytic Solution Tank The electrolytic solution 3 is a liquid having an ionic conductivity by dissolving an electrolyte in a solvent. The electrolytic solution 3 is stored in the electrolytic solution tank 2 or circulates in the electrolytic solution tank 2. The type of the electrolytic solution 3 is different depending on the type of the electrode active material contained in the metal electrode 5, but may be an electrolytic solution (aqueous electrolyte solution) using a water solvent.
In addition, the electrolytic solution 3 is a measurement target of the first measurement unit 24.
For example, in the case of a zinc-air battery, an aluminum-air battery, or an iron-air battery, an alkaline aqueous solution such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution can be used as the electrolytic solution. An aqueous sodium chloride solution can be used.

The electrolytic solution tank 2 is an electrolytic cell that stores or distributes the electrolytic solution 3 and has corrosion resistance to the electrolytic solution. Moreover, the electrolytic solution tank 2 can have an electrolytic solution chamber.
The electrolytic solution tank 2 or the electrolytic solution chamber has a structure in which the metal electrode 5 can be installed so that it can be taken out. The electrolyte bath 2 can be provided in the metal-air battery main body. Moreover, the electrolytic solution tank 2 may have a plurality of electrolytic solution chambers.

The metal-air battery 30 may have a mechanism for causing the electrolytic solution 3 in the electrolytic solution tank 2 to flow. As a result, the anode reaction at the metal electrode 5 can be promoted, and the performance of the metal-air battery 30 can be improved. As a mechanism for flowing the electrolytic solution, the electrolytic solution 3 may be circulated using a pump and a circulation flow path, and the electrolytic solution 3 in the electrolytic solution tank 2 may be flowed.
Moreover, the metal air battery 30 may be provided with a movable part that can physically move the electrolyte 3 in the electrolyte bath 2 such as a stirrer and a vibrator.

The material of the housing 1 constituting the electrolytic solution tank 2 is not particularly limited as long as the material has corrosion resistance to the electrolytic solution. For example, polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyvinyl acetate, ABS, vinylidene chloride, polyacetal, polyethylene, polypropylene, polyisobutylene, fluororesin, epoxy resin, etc.

5. Metal electrode The metal electrode 5 is an electrode that serves as an anode, and includes a metal that is an electrode active material of the anode. Moreover, the metal electrode 5 can be provided in the electrolyte solution tank 2 so that it can be taken out.
The metal electrode 5 may be, for example, a metal plate containing a metal that is an electrode active material. In addition, the metal electrode 5 may include, for example, a metal electrode current collector and an electrode active material layer provided on the metal electrode current collector.
The electrode active material contained in the metal electrode 5 is a metal that generates a charge in the metal electrode 5 by an anodic reaction and dissolves in the electrolyte as metal-containing ions. For this reason, the electrode active material contained in the metal electrode 5 is gradually consumed as the anode reaction proceeds. When the electrode active material contained in the metal electrode 5 decreases, the charge generated in the metal electrode 5 decreases and the metal electrode 5 is used. By removing the used metal electrode 5 from the electrolytic solution tank 2 and inserting a new metal electrode 5 into the electrolytic solution tank 2, power generation by the metal-air battery 30 can be continued.
The charge generated in the metal electrode 5 is output to the outside as a discharge current and then used for the cathode reaction in the air electrode 9. This discharge current is a measurement target of the second measurement unit 25.

When the concentration of the metal-containing ions generated in the electrolytic solution 3 by the anodic reaction exceeds the saturation concentration, the metal-containing ions may be deposited in the electrolytic solution 3 as fine particles of metal oxide or metal hydroxide (precipitate 17). . Further, when the concentration of the metal-containing ions reaches the passivating concentration, the metal-containing ions may be deposited on the surface of the metal electrode 5 as a metal oxide or metal hydroxide passivated (precipitate 17). . Therefore, the precipitate 17 may be deposited as fine particles floating in the electrolyte solution or settling on the bottom of the electrolyte solution tank, and may be deposited as a passive material adhering to the surface of the metal electrode 5.

If the precipitate 17 is deposited as fine particles and the fine particles are excessively present in the electrolyte solution 3, the fine particles of the precipitate 17 adhere to the pores of the porous air electrode 9, thereby preventing oxygen gas diffusion. As a result of the fine particles of the precipitate 17 adhering to the pores of the porous separator 14, the ion conduction path of OH ⁻ ions is hindered. As a result, the output of the metal-air battery 30 decreases. For this reason, when the fine particles of the precipitate 17 accumulate in the electrolytic solution, it is necessary to remove the fine particles from the electrolytic solution 3.
When the deposit 17 is deposited as a passive state and this passive state covers most of the surface of the metal electrode 5, the anode reaction on the surface of the metal electrode 5 is inhibited, and the output of the metal-air battery 30 is reduced. For this reason, it is possible to continue the power generation by the metal-air battery 30 by removing the metal electrode 5 whose passivation has covered the surface from the electrolytic solution tank 2 and inserting a new metal electrode 5 into the electrolytic solution tank 2.

For example, in the case of a zinc-air battery, the electrode active material is metallic zinc, and zinc hydroxide or zinc oxide is deposited in the electrolytic solution. In the case of an aluminum air battery, the electrode active material is metallic aluminum, and aluminum hydroxide is deposited in the electrolytic solution. In the case of an iron-air battery, the electrode active material is metallic iron, and iron oxide hydroxide or iron oxide is deposited in the electrolytic solution. In the case of a magnesium air battery, the electrode active material is metallic magnesium, and magnesium hydroxide is deposited in the electrolyte.
In the case of lithium-air batteries, sodium-air batteries, and calcium-air batteries, the electrode active materials are metallic lithium, metallic sodium, and metallic calcium, respectively, and oxides and hydroxides of these metals are contained in the electrolyte. Precipitate. In the case of a lithium air battery, a sodium air battery, or a calcium air battery, a solid electrolyte membrane may be provided between the metal electrode 5 and the electrolytic solution. Thereby, it can suppress that an electrode active material is corroded by electrolyte solution. In this case, the electrode active material is dissolved in the electrolytic solution after ion conduction through the solid electrolyte membrane.
In addition, an electrode active material is not limited to these examples, What is necessary is just a metal air battery. Moreover, although the electrode active material contained in the metal electrode 5 mentioned the metal which consists of a kind of metal element in said example, the electrode active material contained in the metal electrode 5 may be an alloy.

The metal electrode current collector has conductivity. Further, the shape of the metal electrode current collector is preferably a plate shape, a shape provided with a hole penetrating in the thickness direction of the plate, an expanded metal or a mesh. In addition, the metal electrode current collector can be formed of, for example, a metal having corrosion resistance against the electrolytic solution. The material of the metal electrode current collector is, for example, nickel, gold, silver, copper, stainless steel or the like. The metal electrode current collector may be a nickel-plated, gold-plated, silver-plated, or copper-plated conductive substrate. For this conductive substrate, iron, nickel, stainless steel, or the like can be used.
As a result, the charge generated in the metal electrode 5 by the anode reaction can be collected by the metal electrode current collector, and the generated charge can be output to an external circuit. The electrode active material layer may be fixed on the main surface of the metal electrode current collector, for example, by pressing metal particles or lumps that are electrode active materials against the surface of the metal electrode current collector. A metal may be deposited on the current collector by plating or the like. Regarding the shape of the metal electrode current collector, the plate shape is preferable from the viewpoint of conductivity when the electrode active material is deposited by plating, and when the metal particles or lump is fixed, the particles or lump is dropped. From the viewpoint of preventing this, a plate provided with a through hole, or an expanded metal or mesh is preferable.

The metal electrode 5 can constitute a metal electrode holder together with the metal electrode support. The metal electrode holder is provided so that the metal electrode 5 can be inserted into the electrolytic solution tank 2 and the used metal electrode 5 can be extracted from the electrolytic solution tank 2. As a result, the electrode active material can be supplied to the metal-air battery 30.
A metal electrode support body can be provided so that it may become a lid | cover of the electrode insertion port provided in the metal air battery main body. Thus, the metal electrode 5 can be inserted into the electrolytic solution tank 2 and the electrode insertion port can be covered, and the reaction between the components in the atmosphere and the electrolytic solution 3 can be suppressed.

6). Air electrode The air electrode 9 is an electrode having an air electrode catalyst and serving as a cathode. Further, the air electrode 9 may include a porous gas diffusion layer 8 and a porous air electrode catalyst layer 7 provided on the gas diffusion layer 8. In the air electrode 9, water supplied from the electrolytic solution 3 and the like, oxygen gas supplied from the atmosphere, and electrons react on the air electrode catalyst to generate hydroxide ions (OH ⁻ ) (cathode reaction). That is, the cathode reaction proceeds at the three-phase interface of the air electrode 9.
The air electrode 9 is provided so that oxygen gas contained in the atmosphere can diffuse into the air electrode 9. For example, the air electrode 9 can be provided so that at least a part of the surface of the air electrode 9 is exposed to the atmosphere. In the metal-air battery 30 shown in FIG. 1, a plurality of holes 23 are provided in the housing 1, and oxygen gas contained in the atmosphere can diffuse into the air electrode 9 through the holes 23. Further, for example, an air flow path through which air flows may be formed and oxygen gas may be supplied to the air electrode 9. Note that water may be supplied to the air electrode 9 through this air flow path.

The air electrode catalyst layer 7 may include, for example, a conductive porous carrier and an air electrode catalyst supported on the porous carrier. This makes it possible to form a three-phase interface in which oxygen gas, water, and electrons coexist on the air electrode catalyst, thereby allowing the cathode reaction to proceed. The air electrode catalyst layer 7 may contain a binder.
The air electrode 9 composed of the air electrode catalyst layer 7 and the gas diffusion layer 8 is produced by applying a porous carrier carrying the air electrode catalyst to the conductive porous substrate (gas diffusion layer 8). May be. For example, the air electrode 9 can be produced by applying carbon carrying an air electrode catalyst to carbon paper or carbon felt. The gas diffusion layer 8 may function as an air electrode current collector.
The thickness of the air electrode 9 can be, for example, not less than 300 μm and not more than 3 mm.
The air electrode 9 can be electrically connected to the air electrode terminal 10. Thereby, the electric charge generated in the air electrode catalyst layer 7 can be taken out to the external circuit.

The metal-air battery 30 may include an air electrode current collector that collects charges generated in the air electrode catalyst layer 7. As a result, charges generated in the air electrode catalyst layer 7 can be efficiently taken out to the external circuit. The material of the air electrode current collector is not particularly limited as long as it has corrosion resistance with respect to the electrolytic solution 3, and examples thereof include nickel, gold, silver, copper, and stainless steel. The air electrode current collector may be a nickel-plated, gold-plated, silver-plated, or copper-plated conductive substrate. For this conductive substrate, iron, nickel, stainless steel, or the like can be used.
The shape of the air electrode current collector can be, for example, a plate shape, a mesh shape, a punching metal, or the like.
In addition, as a method of joining the air electrode current collector and the porous carrier or the conductive porous substrate (gas diffusion layer 8), a method of pressure bonding by screwing through a frame, or a conductive adhesive can be used. The method of using and combining is mentioned.

The air electrode 9 included in one cell may be provided only on one side of the metal electrode 5, or may be provided on both sides of the metal electrode 5 as shown in FIG.
Examples of the porous carrier contained in the air electrode catalyst layer 7 include carbon black such as acetylene black, furnace black, channel black and ketjen black, and conductive carbon particles such as graphite and activated carbon. In addition, carbon fibers such as vapor grown carbon fiber (VGCF), carbon nanotube, carbon nanowire, and the like can be used.
Examples of the air electrode catalyst include fine particles made of platinum, iron, cobalt, nickel, palladium, silver, ruthenium, iridium, molybdenum, manganese, lanthanum, these metal compounds, and alloys containing two or more of these metals. Can be mentioned. This alloy is preferably an alloy containing at least two of platinum, iron, cobalt, and nickel. For example, platinum-iron alloy, platinum-cobalt alloy, iron-cobalt alloy, cobalt-nickel alloy, iron-nickel alloy And iron-cobalt-nickel alloy.
The binder contained in the air electrode catalyst layer 7 is, for example, polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF).
Further, the porous carrier contained in the air electrode catalyst layer 7 may be subjected to a surface treatment so that a cationic group exists as a fixed ion on the surface thereof. As a result, hydroxide ions can be conducted on the surface of the porous carrier, so that the hydroxide ions generated on the air electrode catalyst can easily move.
The air electrode catalyst layer 7 may have an anion exchange resin supported on a porous carrier. Thereby, since hydroxide ions can be conducted through the anion exchange resin, the hydroxide ions generated on the air electrode catalyst are easily moved.

The air electrode catalyst layer 7 may be provided so as to be in contact with the electrolytic solution 3 in the electrolytic solution tank 2. Thus, hydroxide ions generated in the air electrode catalyst layer 7 can easily move to the electrolyte solution 3. Further, water necessary for the electrode reaction in the air electrode catalyst layer 7 is easily supplied from the electrolytic solution 3 to the air electrode catalyst layer 7.

Further, the air electrode catalyst layer 7 may be provided so as to be in contact with the separator 14 that is in contact with the electrolytic solution 3 accommodated in the electrolytic solution tank 2. The separator 14 can be a porous resin membrane, an ion exchange membrane or a nonwoven fabric of resin fibers. The separator 14 can be provided so as to partition the electrolytic solution 3 in the electrolytic solution tank 2 and the air electrode catalyst layer 7. By providing the separator 14, the electrolyte 3 can be prevented from leaking outside the metal-air battery 30 through the pores of the air electrode 9, and the safety of the metal-air battery 30 can be improved. . Moreover, since the water contained in the electrolytic solution 3 penetrates into the air electrode 9 after passing through the separator 14, it is possible to suppress excess water from being supplied to the air electrode 9. In addition, by providing the separator 14, it is possible to prevent the electrode active material contained in the electrolytic solution 3 and the extremely fine particles of the precipitate 17 from adhering to the air electrode catalyst layer 7.

Further, by using the separator 14 as an ion exchange membrane, the ion species moving between the air electrode catalyst layer 7 and the electrolytic solution 3 can be limited. The separator 14 may be an anion exchange membrane. As a result, hydroxide ions generated in the air electrode catalyst layer 7 can conduct through the anion exchange membrane and move to the electrolytic solution. Since the anion exchange membrane has a cation group which is a fixed ion, the cation in the electrolytic solution 3 cannot be conducted to the air electrode catalyst layer 7. On the other hand, since the hydroxide ions generated in the air electrode catalyst layer 7 are anions, they can be conducted to the electrolytic solution 3. As a result, the battery reaction of the metal-air battery 30 can proceed, and the cations in the electrolyte aqueous solution 3 can be prevented from moving to the air electrode catalyst layer 7. Thereby, precipitation of the metal and carbonate compound in the air electrode catalyst layer 7 can be suppressed.

The material of the porous resin film or the nonwoven fabric of resin fibers used for the separator 14 can be an alkali-resistant resin, for example, polyethylene, polypropylene, nylon 6, nylon 66, polyolefin, polyvinyl acetate, polyvinyl alcohol-based material. And polytetrafluoroethylene (PTFE). The pore diameter of the pores of the separator 14 is not particularly limited, but is preferably 30 μm or less. The separator 14 is preferably subjected to a hydrophilic treatment so as to improve the flow of the electrolytic solution.
Examples of the ion exchange membrane used in the separator 14 include perfluorosulfonic acid, perfluorocarboxylic acid, styrene vinylbenzene, and quaternary ammonium solid polymer electrolyte membranes (anion exchange membranes).

7). 1st measurement part, 2nd measurement part, notification part The 1st measurement part 24 is provided so that the physical property value etc. can be measured by making the electrolyte solution 3 into a measuring object. The first measuring unit 24 may be provided so as to measure the physical property value of the electrolytic solution 3 in the electrolytic solution tank 2 like the metal-air battery 30 shown in FIG. The liquid 3 may be sampled so that the physical property value of the electrolytic solution 3 can be measured. Further, when the electrolytic solution 3 in the electrolytic solution tank 2 is circulated by the circulation flow path and the pump, the first measurement unit 24 may be provided so that the physical property value of the electrolytic solution 3 can be measured in the circulation flow path. Alternatively, the electrolytic solution 3 in the circulation channel may be sampled so that the physical property value of the electrolytic solution 3 can be measured.
The 1st measurement part 24 is good also considering only the electrolyte solution 3 as a measuring object, and is good also considering the mixture of the electrolyte solution 3 and the microparticles | fine-particles of the precipitate 17 as a measuring object.
For example, the first measurement unit 24 can measure physical property values such as pH value, ORP, conductivity, viscosity, density, etc., with the electrolytic solution 3 as a measurement target. The first measurement unit 24 may be provided to measure other physical property values that are related to the OH ⁻ ion concentration or the metal-containing ion concentration in the electrolytic solution.
Moreover, the 1st measurement part 24 may be provided so that two or more types of physical property values can be measured. The first measurement unit 24 is, for example, a pH meter, an ORP meter, a conductivity meter, a viscometer, a density meter, or the like.

The second measuring unit 25 is provided so that the current value, voltage value, discharge capacity, integrated discharge capacity, and the like can be measured using the discharge current of the metal-air battery 30 as a measurement target. The 2nd measurement part 25 can be provided in the circuit which outputs the electromotive force between the metal electrode 5 and the air electrode 9, for example. The second measuring unit 25 is an ammeter, for example.

The metal-air battery 30 may include an arithmetic circuit 26 that calculates battery information from the measurement result of the first measurement unit 24 or the measurement result of the second measurement unit 25. The arithmetic circuit 26 may be provided so as to calculate battery information from both the measurement result of the first measurement unit 24 and the measurement result of the second measurement unit 25.
Further, the metal-air battery 30 may include a storage medium 28 from which the arithmetic circuit 26 can read data. In the storage medium 28, the measurement result of the first measurement unit 24, the measurement result of the second measurement unit 25, the battery information calculated from these measurement results, the data of the calibration curve necessary for calculation by the arithmetic circuit 26, etc. Can be recorded.
The battery information includes, for example, information indicating the remaining amount of the electrode active material contained in the metal electrode 5, information indicating the dischargeable time, information indicating the ion concentration of the electrolytic solution 3, and the amount of the precipitate 17 generated from the electrode active material. Information indicating the discharge timing of the precipitate 17, information indicating the timing of supplying the electrolytic solution or water to the electrolytic solution tank 2, information indicating the amount of the electrolytic solution or water supplied to the electrolytic solution tank 2, and the like. .
The arithmetic circuit 26 or the storage medium 28 may be included in the first measurement unit 24 or the second measurement unit 25 or may be included in the notification unit 27.
The arithmetic circuit 26 may be provided so as to output the calculated battery information to the notification unit 27.

The notification unit 27 is provided to notify a user or the like of battery information based on the measurement result of the first measurement unit 24. Further, the notification unit 27 may be provided so as to notify the user or the like of battery information based on the measurement result of the second measurement unit 25. Further, the notification unit 27 may be provided so as to notify a user or the like of battery information based on both the measurement result of the first measurement unit 24 and the measurement result of the second measurement unit 25. The notification unit 27 may be provided to notify the battery information calculated by the arithmetic circuit 26.
The notification unit 27 may include a display unit for notifying the user of battery information. By displaying the battery information on the display unit, the battery information can be notified to the user or the like. The display unit may be a display or a lamp.
In addition, the notification unit 27 may include an audio output unit for notifying a user or the like of battery information. The battery information can be notified to the user or the like by outputting the battery information from the voice output unit as voice.

In addition, the notification unit 27 may be provided so as to notify battery information to a remote user or administrator using a data communication line. Thus, a remote user or administrator can know the battery information and can monitor the metal-air battery 30. Accordingly, for example, a remote administrator or management company can manage and maintain the metal-air battery 30. In addition, a remote manager or management company can simultaneously monitor the plurality of metal air batteries 30.
In this case, the notification unit 27 can include a communication port such as a LAN port or a wireless communication port. The battery information can be communicated from the communication port to a server or the like installed at a remote place, and the battery information can be displayed or output by the server.

The 1st measurement part 24 can be provided so that the pH value of the electrolyte solution 3 can be measured, for example. Further, the first measuring unit 24 may be provided so as to measure the ORP of the electrolytic solution 3. In this case, the first measurement unit 24 is a pH meter or an ORP meter. Further, the first measurement unit 24 may be a pH meter having a glass electrode or a pH meter having an ion response field effect transistor. Further, the first measuring unit 24 can continuously measure the pH value of the electrolytic solution 3.

The pH value of the electrolytic solution 3 is a value reflecting the OH ⁻ ion concentration of the electrolytic solution 3. For this reason, there is a correlation between the pH value of the electrolytic solution 3 and the OH ⁻ ion concentration.
Therefore, when the relationship between the OH ⁻ ion concentration of the electrolytic solution 3 accommodated in the electrolytic solution tank 2 and the pH value of the electrolytic solution 3 is measured in advance and a calibration curve is prepared, the measurement result of the first measuring unit 24 is obtained. The OH ⁻ ion concentration of the electrolytic solution 3 can be calculated from the pH value of the electrolytic solution 3. The OH ⁻ ion concentration can be calculated by the arithmetic circuit 26. The calculated OH ⁻ ion concentration can be notified to the user or the like by the notification unit 27. Further, by continuously measuring the pH value of the electrolytic solution 3, it is possible to notify the user of the fluctuation of the OH ⁻ ion concentration.
In addition, since there is a correlation between the OH ⁻ ion concentration and the metal-containing ion concentration of the electrolytic solution, there is also a correlation between the pH value of the electrolytic solution 3 and the metal-containing ion concentration. For this reason, when the relationship between the pH value of the electrolytic solution 3 and the metal-containing ion concentration is measured in advance and a calibration curve is prepared, the metal-containing ion concentration can be calculated from the pH value of the electrolytic solution 3. The notification unit 27 may notify the user or the like of this metal-containing ion concentration.
Note that calibration curve data and the like can be stored in the storage medium 28.

The 1st measurement part 24 can be provided so that the electrical conductivity of the electrolyte solution 3 can be measured, for example. In this case, the first measuring unit 24 may measure the conductivity of the electrolytic solution 3 including the fine particles of the precipitate 17. Moreover, the 1st measurement part 24 may be provided so that electrical conductivity may be measured by the alternating current 2 electrode method, and may be provided so that electrical conductivity may be measured by an electromagnetic induction method.

The conductivity of the electrolytic solution 3 reflects the concentration of ions having the highest transport number in the electrolytic solution. For example, when the electrolytic solution 3 is an alkaline aqueous solution such as an aqueous potassium hydroxide solution or an aqueous sodium hydroxide solution, the conductivity of the electrolytic solution 3 reflects the OH ⁻ ion concentration. For this reason, there is a correlation between the conductivity of the electrolytic solution 3 and the OH ⁻ ion concentration.
Therefore, when the relationship between the OH ⁻ ion concentration of the electrolytic solution 3 accommodated in the electrolytic solution tank 2 and the conductivity of the electrolytic solution 3 is measured in advance and a calibration curve is prepared, the measurement result of the first measuring unit 24 is obtained. The OH ⁻ ion concentration of the electrolytic solution 3 can be calculated from the conductivity of the electrolytic solution 3. The OH ⁻ ion concentration can be calculated by the arithmetic circuit 26. Further, the calculated OH ⁻ ion concentration can be notified to the user or the like by the notification unit 27 as information indicating the ion concentration. In addition, by continuously measuring the conductivity of the electrolytic solution 3, it is possible to notify the user of fluctuations in the OH ⁻ ion concentration.
In addition, since there is a correlation between the OH ⁻ ion concentration and the metal-containing ion concentration of the electrolytic solution, there is also a correlation between the conductivity of the electrolytic solution 3 and the metal-containing ion concentration. For this reason, if the relationship between the electrical conductivity of the electrolytic solution 3 and the metal-containing ion concentration is measured in advance and a calibration curve is prepared, the metal-containing ion concentration can be calculated from the electrical conductivity of the electrolytic solution 2. The notification unit 27 may notify the user or the like of this metal-containing ion concentration.

The 1st measurement part 24 can be provided so that the viscosity of the electrolyte solution 3 may be measured, for example. In this case, the first measurement unit 24 may measure the viscosity of the electrolytic solution 3 including the fine particles of the precipitate 17. The first measuring unit 24 is, for example, a tuning fork vibration type viscometer.

The viscosity of the electrolytic solution 3 is a value that reflects the amount of the heaviest metal-containing ions in the electrolytic solution. In the case of a zinc-air battery, the viscosity of the electrolytic solution 3 is a value that reflects the amount of Zn (OH) ₄ ^2- ion concentration. For this reason, there is a correlation between the viscosity of the electrolytic solution 3 and the metal-containing ion concentration.
Therefore, when the relationship between the metal-containing ion concentration of the electrolytic solution 3 accommodated in the electrolytic solution tank 2 and the viscosity of the electrolytic solution 3 is measured in advance and a calibration curve is prepared, the electrolysis that is the measurement result of the first measuring unit 24 is obtained. The metal-containing ion concentration of the electrolytic solution 3 can be calculated from the viscosity of the liquid 3. The metal-containing ion concentration can be calculated by the arithmetic circuit 26. In addition, the calculated metal-containing ion concentration can be notified to the user or the like by the notification unit 27 as information representing the ion concentration. Further, by continuously measuring the viscosity of the electrolytic solution 3, it is possible to notify the user of fluctuations in the metal-containing ion concentration.
Further, since the OH ⁻ ion concentration and the metal-containing ion concentration of the electrolytic solution are correlated, there is also a correlation between the viscosity of the electrolytic solution 3 and the OH ⁻ ion concentration. For this reason, when the relationship between the viscosity of the electrolytic solution 3 and the OH ⁻ ion concentration is measured in advance and a calibration curve is prepared, the OH ⁻ ion concentration can be calculated from the viscosity of the electrolytic solution 2. The notification unit 27 may notify the user or the like of the OH ⁻ ion concentration.

The 1st measurement part 24 can be provided so that the density of the electrolyte solution 3 may be measured, for example. In this case, the first measuring unit 24 may measure the density of the electrolytic solution 3 including the fine particles of the precipitate 17. The first measurement unit 24 is, for example, a vibration type density meter.

The density of the electrolytic solution 3 is a value that reflects the amount of the heaviest metal-containing ions in the electrolytic solution. In the case of a zinc-air battery, the density of the electrolytic solution 3 is a value that reflects the amount of Zn (OH) ₄ ^2- ion concentration. For this reason, there is a correlation between the density of the electrolytic solution 3 and the metal-containing ion concentration.
Therefore, when the relationship between the metal-containing ion concentration of the electrolytic solution 3 accommodated in the electrolytic solution tank 2 and the density of the electrolytic solution 3 is measured in advance and a calibration curve is created, the electrolysis that is the measurement result of the first measuring unit 24 is obtained. The metal-containing ion concentration of the electrolytic solution 3 can be calculated from the density of the liquid 3. The metal-containing ion concentration can be calculated by the arithmetic circuit 26. In addition, the calculated metal-containing ion concentration can be notified to the user or the like by the notification unit 27 as information representing the ion concentration. Further, by continuously measuring the density of the electrolytic solution 3, it is possible to notify the user of fluctuations in the metal-containing ion concentration.
Further, since the OH ⁻ ion concentration and the metal-containing ion concentration of the electrolytic solution are correlated, there is also a correlation between the density of the electrolytic solution 3 and the OH ⁻ ion concentration. For this reason, if the relationship between the density of the electrolytic solution 3 and the OH ⁻ ion concentration is measured in advance and a calibration curve is prepared, the OH ⁻ ion concentration can be calculated from the density of the electrolytic solution 2. The notification unit 27 may notify the user or the like of the OH ⁻ ion concentration.

When the first measurement unit 24 is provided so as to measure two or more physical property values, the arithmetic circuit 26 is provided to calculate the OH ⁻ ion concentration or the metal-containing ion concentration from two or more physical property values. May be. As a result, a more accurate OH ^- ion concentration or metal-containing ion concentration can be calculated.

The 2nd measurement part 25 can be provided so that the integrated discharge capacity of the metal air battery 30 can be measured, for example. In the anodic reaction, as shown in Chemical Formula 2 above, the electrode active material and OH ⁻ ions react to generate a charge on the metal electrode 5. Since this electric charge is discharged to an external circuit, there is a correlation between the integrated discharge capacity and the consumption of the electrode active material. For this reason, the consumption amount of the electrode active material can be calculated from the accumulated discharge capacity measured by the second measuring unit 25. Further, the remaining amount of the electrode active material contained in the metal electrode 5 can be calculated from the amount of the electrode active material contained in the metal electrode 5 before discharge and the consumption of the electrode active material.
For example, when the amount of the electrode active material contained in the metal electrode 5 before discharge is M1, and the consumption of the electrode active material calculated from the accumulated discharge capacity measured by the second measuring unit 25 is M2, the electrode active material The remaining amount of the substance can be expressed as:
Remaining amount (%) = (M1-M2) ÷ M2 × 100
These calculations can be performed by the arithmetic circuit 26. The calculated remaining amount of the electrode active material can be notified to the user or the like by the notification unit 27 as information indicating the remaining amount of the electrode active material.
Note that the remaining amount of the electrode active material may be calculated / notified with the unit of Ah.

The notification unit 27 that notifies the user of the remaining amount is a display, a lamp, and an audio output unit. The information to be notified is quantitative numerical information regarding the remaining amount, the non-determining information indicating whether the remaining amount has approached zero, or whether the remaining amount has reached zero. Also good.
Notification of quantitative numerical information includes a method of displaying the numerical value itself or a figure obtained by converting the numerical information into a length and an angle on a display, or displaying by lighting a lamp composed of a plurality of segments. As a result of the non-judgment of the remaining amount, in the notification of information when applicable, the sentence indicating that the remaining amount satisfies the non-judgment condition is displayed on the display or notified by voice. An icon that has a one-to-one correspondence is displayed on the display, a lamp that has a one-to-one correspondence with the non-determination of the remaining amount is lit, and a sound pattern that has a one-to-one correspondence with the non-determination of the remaining amount is generated. There are methods such as
When the remaining amount approaches zero or reaches zero, the control unit may stop the power output from the metal-air battery together with the notification. By stopping the power output, overdischarge of the metal electrode 5 can be suppressed, and deterioration of the metal electrode 5 can be suppressed.

The notification unit 27 may be provided so as to notify a user or the like of information indicating the dischargeable time based on the measurement result of the first measurement unit 24 or the second measurement unit 25. The information indicating the dischargeable time may be, for example, the remaining dischargeable time or a numerical value indicating the dischargeable time.
The dischargeable time is the remaining time that can be discharged by the metal-air battery 30. In the metal-air battery 30, when the remaining amount of the electrode active material contained in the metal electrode 5 becomes small, it becomes impossible to discharge, and the precipitate 17 is deposited on the surface of the metal electrode 5 as a passive state by the precipitation reaction. There are cases where discharge cannot be performed due to inhibition of the reaction.
When the remaining amount of the electrode active material is reduced and the discharge is stopped, the dischargeable time and the remaining amount of the electrode active material are proportional to each other. Can be calculated. Therefore, the notification unit 27 can notify information indicating the dischargeable time based on the measurement result of the second measurement unit 25. Thus, the user or the like can replace the metal electrode 5 at an appropriate time.
When the dischargeable time calculated based on the measurement result of the second measurement unit 25 is shorter than the dischargeable time calculated based on the measurement result of the first measurement unit 24 described later, the notification unit 27 2 Notifies the dischargeable time calculated based on the measurement result of the measurement unit 25. When the dischargeable time calculated based on the measurement result of the first measurement unit 24 is short, the notification unit 27 notifies the dischargeable time. The selection of the dischargeable time can be OR controlled.

The notification unit 27 that notifies the user of information indicating the dischargeable time is a display, a lamp, or an audio output unit. The information to be notified is quantitative numerical information related to the dischargeable time, non-determination information indicating whether the dischargeable time has approached zero, or whether the dischargeable time has been reached. May be.
Notification of quantitative numerical information includes a method of displaying the numerical value itself or a figure obtained by converting the numerical information into a length and an angle on a display, or displaying by lighting a lamp composed of a plurality of segments. As a result of the non-determination of the dischargeable time, in the case of corresponding information, a message indicating that the dischargeable time satisfies the non-judgment condition is displayed on the display or notified by voice. An icon corresponding to the non-determination of the non-determination of the display is displayed on the display, a lamp corresponding to the non-determination of the dischargeable time is turned on, and the non-determination of the dischargeable time is corresponding to the non-determination. There is a method of generating a sound pattern.
Moreover, when the dischargeable time approaches zero or reaches zero, the control unit may stop the power output from the metal-air battery together with the notification. By stopping the power output, it is possible to suppress the surface of the metal electrode 5 from being covered with the passive state, and the utilization factor of the electrode active material contained in the metal electrode 5 can be increased.

When the discharge is stopped due to inhibition of the anode reaction due to the passivation of the precipitate 17, the dischargeable time is the remaining time until the surface of the metal electrode 5 is covered with the passivation of the precipitate 17.
When the chemical reaction as in Chemical Formula 2 proceeds and the metal-containing ion concentration exceeds the saturation concentration, the precipitation reaction as shown in Chemical Formula 3 and Chemical Formula 4 proceeds. However, it is considered that the reaction rate of the precipitation reaction in which the fine particle precipitates 17 are deposited in the electrolytic solution is very slow. Even if the concentration of the metal-containing ion exceeds the saturation concentration, the concentration of the metal-containing ion increases. Becomes oversaturated. Then, when the metal-containing ion concentration reaches a threshold value at which a passive state is formed, the precipitate 17 is deposited on the surface of the metal electrode 5 as a passive state, and the anode reaction is considered to be inhibited. In addition, when the OH ⁻ ion concentration falls below the threshold value, the supply of OH ⁻ ions necessary for the anode reaction is insufficient, so that the precipitate 17 is deposited on the surface of the metal electrode 5 as a passive state, thereby inhibiting the anode reaction. It is thought that it is done.
The metal-containing ion concentration or OH ^- threshold passivation is formed of the ion concentration is thought to depend on the temperature.

The pH value and conductivity of the electrolytic solution 3 are values that reflect the OH ⁻ ion concentration of the electrolytic solution 3, and the viscosity and density of the electrolytic solution 3 are values that reflect the metal-containing ion concentration of the electrolytic solution. Passivity is formed when the pH value, conductivity, viscosity or density of the electrolyte 3 reaches or falls below a certain threshold. Accordingly, the pH value, conductivity, viscosity, or density threshold at which passivity is formed can be measured in advance and stored in the storage medium 28. Thus, based on the measurement result of the first measurement unit 24 and the data recorded in the storage medium 28, the time until the pH value, conductivity, viscosity, or density reaches the threshold value at which passivity is formed (dischargeable time) ) Can be calculated by the arithmetic circuit 26. Therefore, based on the measurement result of the first measurement unit 24, the notification unit 27 can notify the user or the like of information indicating the dischargeable time. Thus, the user or the like can know the discharge stop time in advance.
In addition, it becomes possible to stop the discharge before the surface of the metal electrode 5 is covered with the passive state, and it is possible to prevent the surface of the metal electrode 5 from being covered with the passive state.
In addition, after the discharge is stopped before the surface of the metal electrode 5 is covered with the passive state, a discharge stop period can be provided. In this discharge stop period, it is considered that the precipitation reaction in which the fine particles 17 precipitate in the electrolytic solution proceeds, so that the metal-containing ion concentration decreases and the OH ⁻ ion concentration increases. For this reason, it becomes possible to perform re-discharge after a discharge stop period, and the utilization efficiency of the electrode active material contained in the metal electrode 5 can be raised.
In addition, since the metal-containing ion concentration or the OH ⁻ ion concentration during the discharge stop period can be measured by the first measurement unit 24, the notification unit 27 notifies the user or the like with information indicating the time when re-discharge is possible. Also good.

The notification unit 27 that notifies the user of information indicating when discharge is stopped or when re-discharge is possible is a display, a lamp, or a sound output unit. The information to be notified may be quantitative numerical information related to the time, the non-determining information indicating whether the time has approached, or whether the time has been reached.
Notification of quantitative numerical information includes a method of displaying the numerical value itself or a figure obtained by converting the numerical information into a length and an angle on a display, or displaying by lighting a lamp composed of a plurality of segments. As a result of the non-determination of the discharge stop timing or the time during which re-discharge can be performed, the notification of information in the case of being applicable indicates that the discharge stop timing or the time during which re-discharge can be performed satisfies the non-determination condition. A sentence is displayed on the display, or is notified by voice, a discharge stop time, or an icon that has a one-to-one correspondence with the non-determination of re-dischargeable time, a discharge stop time, or Lamps that have a one-to-one correspondence with the non-determination of re-discharging time are generated, and a sound pattern that has a one-to-one correspondence with the non-determination of the discharge stop timing or re-dischargeable time is generated There are methods such as
Moreover, when the discharge stop time approaches or arrives, the control unit may stop the power output from the metal-air battery together with the notification. By stopping the power output, it is possible to suppress the surface of the metal electrode 5 from being covered with the passive state, and the utilization factor of the electrode active material contained in the metal electrode 5 can be increased.
Furthermore, when the time when re-discharge is possible is reached, the power output from the metal-air battery may be resumed by the control unit together with the notification. By restarting the power output, the opportunity for power supply from the metal-air battery can be maximized, which increases the convenience for the user.

The relationship between the pH, conductivity, viscosity or density of the electrolyte and the dischargeable time can be measured in advance, and a calibration curve or the like based on the measurement result can be recorded in the storage medium 28.
The first measuring unit 24 may include a thermometer that measures the temperature of the electrolytic solution 3. This makes it possible to accurately predict the threshold value at which passivity is formed.

Further, the notification unit 27 may be provided so as to notify the user or the like of information indicating the dischargeable time as a dischargeable amount (%). For example, if the OH ion concentration, conductivity, viscosity, or density calculated from the pH of the electrolyte when the metal-containing ion concentration reaches the saturation concentration is x, the metal-containing ion concentration reaches the threshold value at which passivity is formed. The OH ion concentration, conductivity, viscosity or density calculated from the pH of the electrolyte solution is y, and the OH ion concentration, conductivity, viscosity or density calculated from the pH measured by the first measurement unit 24 is When z is assumed, the dischargeable amount (%) can be expressed as follows.
Dischargeable amount (%) = (| yz | ÷ | yx |) × 100
For example, when measuring the electrical conductivity as the physical property value of the electrolytic solution, the threshold value y at which the passivation is formed is that the metal-air battery is a zinc-air battery, and a 5 to 10M potassium hydroxide aqueous solution is used as the electrolytic solution. In this case, 0.25 S / cm or more and 0.35 S / cm or less is desirable, and more preferably 0.3 S / cm or more and 0.33 S / cm or less.

The notification unit 27 is provided so as to notify a user or the like of information indicating the amount of the precipitate 17 in the electrolytic solution tank 2 based on the measurement result of the first measurement unit 24 and the measurement result of the second measurement unit 25. Also good.
Since the electrode active material contained in the metal electrode 5 is changed into a metal-containing ion in the electrolytic solution or a precipitate 17 in the electrolytic solution tank 2 by a battery reaction, the amount of the precipitate 17 in the electrolytic solution tank 2 is as follows. It can be obtained by an expression.
Amount of precipitate = (consumption of electrode active material)-(amount of metal-containing ions in electrolyte)
The consumption amount of the electrode active material can be calculated from the accumulated discharge capacity measured by the second measuring unit 25 as described above.
The amount of metal-containing ions in the electrolytic solution can be calculated by multiplying the concentration of metal-containing ions in the electrolytic solution by the amount of electrolytic solution 3 in the electrolytic solution tank 2.
In addition, the metal-containing ion concentration is correlated with the pH value, conductivity, viscosity, or density of the electrolytic solution as described above. Accordingly, the metal-containing ion concentration is calculated from the measurement result of the first measurement unit 24 by measuring the relationship between the pH value, conductivity, viscosity or density of the electrolytic solution and the metal-containing ion concentration in advance and creating a calibration curve. be able to.
Therefore, when data such as a calibration curve and the amount of the electrolytic solution are recorded in the storage medium 28, the calculation circuit 26 determines the precipitate 17 based on the measurement result of the first measurement unit 24 and the measurement result of the second measurement unit 25. The amount can be calculated. Based on the calculation result, the notification unit 27 can notify a user or the like of information indicating the amount of the precipitate 17 in the electrolytic solution tank 2. Thereby, the user etc. can perform the maintenance which removes the deposit 17 in the electrolyte tank 2 at an appropriate time.
Further, the information indicating the amount of the precipitate 17 may be an accumulation rate (%) of the precipitate 17. The accumulation rate of the precipitate 17 can be calculated from the accumulation amount Q and the amount P of the precipitate 17 by previously determining the accumulation amount Q for discharging the precipitate 17 from the electrolytic solution tank 2. For example, it can be calculated by the following equation. In addition, the accumulation amount Q can be set to an amount that can recover the particulate precipitate 17 in the electrolytic solution tank 2 without any trouble.
Accumulation rate of precipitate 17 (%) = | PQ | ÷ Q × 100

In addition, the notification unit 27 notifies the user or the like of information indicating the discharge timing of the precipitate 17 in the electrolytic solution tank 2 based on the measurement result of the first measurement unit 24 and the measurement result of the second measurement unit 25. It may be provided.
In this case, when the accumulation rate (%) of the precipitates 17 reaches 100%, the notification unit 27 can be provided so as to display the discharge time on the display, the lamp, and the audio output unit. Thus, the user or the like can know that the time for discharging the precipitate 17 has come, and can discharge the precipitate 17 from the electrolytic solution tank 2 at an appropriate time. The information to be notified is quantitative numerical information regarding the accumulation rate (%) of the precipitates 17, whether or not the accumulation rate (%) of the precipitation portion 17 has approached 100%, or has reached 100%. It may be the non-determination information indicating whether or not.
Notification of quantitative numerical information includes a method of displaying the numerical value itself or a figure obtained by converting the numerical information into a length and an angle on a display, or displaying by lighting a lamp composed of a plurality of segments. As a result of the non-determination of the accumulation rate (%) of the precipitates 17, a sentence indicating that the accumulation rate (%) of the precipitates 17 satisfies the non-determination condition is displayed on the display for information notification. Or an icon that has a one-to-one correspondence with the non-determination of the accumulation rate (%) of the precipitate 17 that is notified by voice, and a pair with the non-determination of the accumulation rate (%) of the precipitate 17. There are methods such as lighting a lamp that corresponds to one, and generating a sound pattern that corresponds one-to-one with the non-determination of the accumulation rate (%) of the precipitate 17.
When the accumulation rate (%) of the precipitates 17 approaches or reaches 100%, the control unit may stop the power output from the metal-air battery together with the notification. By stopping the power output, the dissolution of the metal-containing ions accompanying the discharge from the metal-air battery is stopped, so that it is possible to prevent excessive formation of the precipitate 17.

Based on the measurement result of the first measurement unit 24 and the measurement result of the second measurement unit 25, the notification unit 27 notifies the user or the like of information indicating the time when the electrolyte solution 2 is replenished with the electrolyte or water. May be provided. The information indicating the time when the electrolytic solution or water is supplied may be, for example, a display indicating that the supply time has come, or a display indicating the time until the supply time.
When the metal-air battery 30 is discharged for a long time, water contained in the electrolytic solution in the electrolytic solution tank 2 is gradually lost, and the amount of the electrolytic solution is gradually reduced.
For example, the moisture contained in the electrolytic solution may be consumed by a battery reaction. When the battery reaction of the metal-air battery 30 proceeds as in the

above chemical formulas

1, 2, and 4, H ₂ O is consumed in the chemical formula 1, but no H ₂ O is generated as a reaction product. For this reason, it is thought that the water | moisture content contained in electrolyte solution is lost gradually with progress of a battery reaction.
Further, for example, moisture contained in the electrolytic solution may be lost due to evaporation at the air electrode 9 or the like. Since O ₂ consumed by the above chemical formula 1 is supplied from the atmosphere, the air electrode 9 is open to the atmosphere. In addition, since the temperature of the air electrode 9 rises due to the reaction heat of Chemical Formula 1, it is considered that the water evaporated in the air electrode 9 diverges into the atmosphere. For this reason, it is thought that the water | moisture content contained in electrolyte solution is lost gradually with progress of a battery reaction.

When water contained in the electrolytic solution is gradually lost, the OH ⁻ ion concentration and the metal-containing ion concentration of the electrolytic solution gradually increase. As described above, the OH ^- ion concentration or the metal-containing ion concentration correlates with the pH value, conductivity, viscosity, or density of the electrolytic solution. Therefore, the measurement results of the first measurement unit 24 and the second measurement unit 25 are obtained by measuring the relationship between the pH value, conductivity, viscosity or density of the electrolytic solution and the water level of the electrolytic solution in advance and creating a calibration curve. From the above, the water level of the electrolyte can be calculated. Based on the calculation result, the notification unit 27 can notify the user or the like of information that represents the time when the electrolytic solution tank 2 is replenished with the electrolytic solution or water.
In addition, a value for replenishing the electrolytic solution or water to the electrolytic solution tank 2 is determined in advance, and when the pH value, conductivity, viscosity, or density of the electrolytic solution reaches this value, the notification unit 27 enters the electrolytic solution tank 2. You may provide so that a user etc. may be notified of the information showing the time which replenishes electrolyte solution or water.
Accordingly, the user or the like can replenish the electrolytic solution tank 2 with the electrolytic solution or water at an appropriate time. Moreover, it can suppress that the area of the metal electrode 5 which contacts the electrolyte solution 3 by the fall of the water level of the electrolyte solution 3 can be suppressed, and it can suppress that the output of the metal air battery 30 falls.

When calculating the water level of the electrolytic solution from the measurement results of the first measurement unit 24 and the second measurement unit 25, the first measurement unit 24 is preferably a pH meter. The pH meter responds linearly to changes in the OH ⁻ ion concentration in the region where the OH ⁻ ion concentration is high. For this reason, it is possible to accurately calculate the water level of the electrolytic solution from the measurement result of the pH meter.
For example, in the case of a zinc-air battery using a 7M potassium hydroxide aqueous solution as an electrolyte, and using a pH meter as the first measuring unit 24, the OH ⁻ ion concentration calculated by pH measurement and the second measurement The water level can be measured by the following formula based on the accumulated discharge capacity obtained by the unit 25: Water level (%) = [{7 (mol / L) −0.7 (mol / L) × 2} × electrolytic solution Electrolyte volume initially present in the tank (L)-Accumulated discharge capacity (Ah) x 3600 ÷ 96500 x 2] ÷ OH ^- ion concentration calculated by pH measurement (mol / L) ÷ Existing electrolyte volume (L)
That is, until the precipitation of zinc oxide, OH were present in the initial electrolyte solution ^- from the amount of ions, OH is consumed by the saturation of the zinc-containing ions ^- the amount of ions, and the chemical formula 1, and, from the formula 2 OH is consumed by discharge reaction comprising ^- an amount of ions by catching, OH contained in the electrolytic solution ^- it can identify the amount of ions. The water level (%) can be determined by comparing this with the OH ⁻ ion concentration calculated by pH measurement.

In the above formula, 0.7 (mol / L) is the saturation concentration of zinc-containing ions when a 7M potassium hydroxide aqueous solution is used, and 2 is consumed from the electrolyte as 1 mol of zinc is dissolved. Is the number of moles of OH ⁻ ions to be produced.
In this case, when the water level (%) reaches the threshold value, the notification unit 27 can be provided so as to display the replacement time on the display, the lamp, and the sound output unit. Thus, the user or the like can know that it is time to replenish, and can replenish the electrolyte in the electrolyte tank 2 at an appropriate time. The information to be notified may be quantitative numerical information related to the water level (%), or the non-determining information indicating whether the water level (%) has approached the threshold value or has reached the threshold value. good.
Notification of quantitative numerical information includes a method of displaying the numerical value itself or a figure obtained by converting the numerical information into a length and an angle on a display, or displaying by lighting a lamp composed of a plurality of segments. As a result of the non-judgment of the water level (%), the notification of information when the water level (%) is applicable, the sentence indicating that the water level (%) satisfies the non-judgment condition is displayed on the display or notified by voice. An icon corresponding to the non-determination of (%) is displayed on the display, a lamp corresponding to the non-determination of the water level (%) is turned on, and a pair of non-determination of the water level (%) is turned on. There is a method such as generating a sound pattern corresponding to one.
When the water level (%) approaches or reaches the threshold value, the control unit may stop the power output from the metal-air battery together with the notification. By stopping the power output, the water level is lowered and the discharge does not continue in a state where it concentrates on a part of the discharge reaction, so that the utilization factor of the electrode active material contained in the metal electrode 5 can be increased.
The water level (%) threshold is preferably 70 to 95%, more preferably 80 to 90%.
In addition, there is a method using a water level meter to measure the water level of the electrolyte, but if the battery is installed in a place where the level is not maintained, the liquid level may be tilted and the accurate water level may not be shown. is there. On the other hand, in the method of calculating the water level based on the measurement result of the first measurement unit 24, the amount of water decrease can be accurately quantified regardless of the battery installation location.

Discharge experiment 1
A zinc-air battery as shown in FIG. 1 was prepared, and the change in the conductivity of the electrolytic solution accompanying the discharge of the zinc-air battery was measured. Note that the manufactured zinc-air battery is not provided with the arithmetic circuit 26, the storage medium 28, the notification unit 27, and the like.
As the metal electrode 5, a zinc plate having a thickness of 10 mm was used. Further, the size of the portion of the metal electrode 5 immersed in the electrolytic solution was 50 mm × 50 mm.
As the air electrode 9, an air electrode catalyst layer 7 and a gas diffusion layer 8 laminated are used. The air electrode 9 had a thickness of about 300 μm and a size of 50 mm × 50 mm.
As the gas diffusion layer 8, 35BC made of SGL carbon was used. 35BC consists of a carbon fiber and a microporous layer, and the microporous layer is a layer made of carbon black and a water repellent resin (PTFE).
As the air electrode catalyst layer 7, a material containing Pt-supported carbon and water-repellent resin (PTFE) was used. In order to increase the reaction surface area, Pt is supported as fine particles on carbon having a large surface area.
As the electrolytic solution, a 7M KOH aqueous solution in which zinc oxide was dissolved to 0.7 mol / L, which is the saturation solubility of zinc oxide, was used.
In addition, a conductivity meter was provided as the first measuring unit 24 so that the sensor unit was immersed in the electrolytic solution 3 in the electrolytic solution tank 2.
An ammeter is provided as the second measuring unit 25.

It discharged with the produced metal air battery, and measured the discharge capacity and the electrical conductivity of electrolyte solution. The result is shown in FIG. As the discharge capacity of the metal-air battery increases, the conductivity of the electrolyte gradually decreases, and when the conductivity of the electrolyte reaches 0.3 to 0.33 S / cm, Discharge stopped and discharge stopped. At this time, it was confirmed that the surface of the metal electrode 5 was covered with the passive film of the precipitate 17. When the conductivity of the electrolyte reaches 0.3 to 0.33 S / cm, the Zn (OH) ₄ ^2- ion concentration of the electrolyte reaches the threshold value for depositing the passive state, and the passive state inhibits the anode reaction. It is thought that the discharge of the metal-air battery has stopped.
From this, it was confirmed that there was a correlation between the conductivity of the electrolytic solution and the Zn (OH) ₄ ^2- ion concentration.

Next, as Example 1, a zinc-air battery was prepared in which the dischargeable amount was displayed on the display as the notification unit 27 based on the measurement result of the conductivity meter. Other configurations are the same as those of the above-described zinc-air battery. The dischargeable amount is 0.5 S / cm (conductivity of the electrolytic solution in which zinc oxide is dissolved up to 0.7 mol / L, which is the saturation solubility of zinc oxide in a 7 M KOH aqueous solution), and is 0.3 S / cm ( The conductivity of the surface of the metal electrode on which the passive film is formed is X2, and the conductivity measured by the conductivity meter is X3, which is calculated by the following formula and displayed on the display.
Dischargeable amount = (X3−X2) ÷ (X1−X2) × 100
Note that the dischargeable amount refers to the time required to reach a state where no further discharge is possible with the formation of the passive film on the surface of the metal electrode even when the electrode active material remains on the metal electrode 5. It is a value used for
Discharge was performed with the produced zinc-air battery. The discharge was stopped before the dischargeable amount displayed on the display as the notification unit 27 became zero. As a result, the discharge can be stopped before the Zn (OH) ₄ ²⁻ ion concentration reaches the threshold value for depositing the passivation, and the metal electrode 5 can be prevented from being covered with the passivation film. It was.

In addition, when the zinc-air battery whose discharge was stopped was left for several hours, the dischargeable amount displayed on the display was recovered, so re-discharge was attempted. In the re-discharge, it was possible to re-discharge the discharge capacity according to the recovered dischargeable amount.
This is because if the zinc-air battery whose discharge is stopped is left unattended, the precipitation reaction of the

above chemical formulas

3 and 4 proceeds in the electrolytic solution 3, so that the OH ⁻ ion concentration in the electrolytic solution increases and Zn (OH) ₄ ^{2 -} presumably because ion concentration is lowered. Therefore, it is considered that the Zn (OH) ₄ ^2- ion concentration in the electrolytic solution changes as shown in FIG. That is, the Zn (OH) ₄ ^2- ion concentration gradually increases during discharge. When the discharge is stopped, the Zn (OH) ₄ ²⁻ ion concentration gradually decreases. Therefore, it is considered that the discharge can be performed again if a sufficient discharge interval is provided. Further, the OH ⁻ ion concentration in the electrolytic solution is considered to change as shown in FIG. That is, the OH ⁻ ion concentration during discharge gradually decreases. When the discharge is stopped, the OH ⁻ ion concentration gradually increases, and it is considered that the discharge can be performed again if a sufficient discharge interval is provided.
Thus, even when the dischargeable amount is reduced, the electrode active material contained in the metal electrode 5 can be efficiently used for the battery reaction by repeating the discharge at intervals of the discharge.
The user can know an appropriate discharge interval from the dischargeable amount displayed on the display as the notification unit 27.

Next, as Comparative Example 1, a zinc-air battery that did not include the first measurement unit 24, the arithmetic circuit 26, the storage medium 28, and the notification unit 27 was produced. Other configurations are the same as those of the zinc-air battery of Example 1.
Discharge was performed with the produced zinc-air battery. After several hours, the discharge output of the metal-air battery became zero and the discharge stopped. At this time, it was confirmed that the surface of the metal electrode 5 was covered with the passive film of the precipitate 17. Further, in this zinc-air battery, since the notification unit 27 is not provided, the user cannot know the dischargeable amount and can stop the discharge before the metal electrode 5 is covered with the passive film. There wasn't.
Moreover, after leaving the zinc-air battery whose discharge stopped for several hours, an attempt was made to re-discharge, but it was not possible to re-discharge. This is presumably because the surface of the metal electrode 5 is covered with a passive film. Therefore, it was found that once the surface of the metal electrode 5 was covered with the passive film, the dischargeable amount could not be recovered even if the zinc-air battery was left standing. In such a case, it is necessary to replace the metal electrode 5 with a new metal electrode 5 or to remove the metal electrode 5 from the zinc-air battery and physically remove the passive film.

Discharge experiment 2
As Example 2, an ammeter that is the second measurement unit 25 that measures the discharge current is provided, and the remaining amount of the electrode active material is displayed on the display that is the notification unit 27 based on the measurement result of the ammeter. A zinc-air battery was prepared. Moreover, the metal electrode 5 used what contained 10g of metal zinc which is an electrode active material. Further, a 7M KOH aqueous solution in which zinc oxide was not dissolved was used as the electrolytic solution. Other configurations are the same as those of the zinc-air battery of Example 1.
The remaining amount of the electrode active material contained in the metal electrode 5 is the cumulative discharge capacity Y (Ah) measured by the second measuring unit 25, the mass of metal zinc contained in the metal electrode 5 (10 g), and the Faraday constant (96500). , The number of charges (2), the atomic weight of zinc (65.4), and the like. Specifically, it was calculated by the following formula.
Remaining amount of electrode active material (%) = (10−Y × 3600 ÷ 96500 ÷ 2 × 65.4) × 100
Discharge was performed with the produced zinc-air battery. Moreover, during discharge, the dischargeable amount and the remaining amount of the electrode active material were displayed on the display serving as the notification unit.
Further, the metal electrode 5 was replaced with a new metal electrode 5 when the remaining amount of the electrode active material displayed on the display decreased.
Therefore, in this zinc-air battery, since the remaining amount of the electrode active material can be known, the metal electrode 5 can be replaced before the discharge output of the metal-air battery decreases, and the discharge accompanying the replacement of the metal electrode 5 The outage period could be shortened.
When the metal electrode 5 was replaced, the remaining amount of the electrode active material was reset to the initial value.

Next, as Comparative Example 2, a zinc-air battery that did not include the first measurement unit 24, the arithmetic circuit 26, the storage medium 28, and the notification unit 27 was produced. Other configurations are the same as those of the zinc-air battery of Example 2.
Discharge was performed with the produced zinc-air battery. After several hours, the discharge output of the metal-air battery became zero and the discharge stopped. After that, the metal electrode 5 that has consumed the electrode active material was replaced with a new metal electrode 5. In this metal-air battery, since the notification unit 27 is not provided, the remaining amount of the electrode active material cannot be known, and the discharge stop period associated with the replacement of the metal electrode 5 becomes long.

Discharge experiment 3
A zinc-air battery similar to that in discharge experiment 1 was prepared, and the calibration curve was prepared by measuring the change in the Zn (OH) ₄ ^2- ion concentration of the electrolyte and the change in the conductivity of the electrolyte due to the discharge. The prepared calibration curve is shown in FIG. It was found that the conductivity of the electrolyte gradually decreased as the Zn (OH) ₄ ^2- ion concentration increased. This is presumably because the OH ⁻ ion concentration decreases as the Zn (OH) ₄ ²⁻ ion concentration increases with the progress of the battery reaction.

Next, as Example 3, a conductivity meter for measuring the electrolyte and an ammeter for measuring the discharge current are provided, and a notification unit based on both the measurement result of the conductivity meter and the measurement result of the ammeter A zinc-air battery was prepared in which the display 27 was notified of the discharge timing of the precipitate 17. Other configurations are the same as those of the zinc-air battery of Example 1.

The precipitation amount P (mol) of the precipitate 17 is determined from the consumption (mol) of the electrode active material calculated from the integrated discharge capacity Z (Ah) measured by an ammeter, the Faraday constant (96500), etc. It can be determined by subtracting the amount (mol) of Zn (OH) ₄ ^2- ion. The amount (mol) of Zn (OH) ₄ ^2- ion in the electrolyte is based on the calibration curve shown in FIG. 5, and the concentration C1 of Zn (OH) ₄ ^2- ion is determined from the conductivity measured by the conductivity meter. (Mol / L) can be calculated, and this concentration can be calculated by multiplying the total amount of electrolyte V1 (L). Specifically, the precipitation amount P was calculated from the following equation.
Precipitation amount P (mol) = Z × 3600 ÷ 96500 ÷ 2-C1 × V1
Further, the accumulation rate (%) of the precipitate 17 is calculated from the accumulation amount Q and the precipitation amount P by previously determining an accumulation amount Q (mol) for discharging the precipitate 17 from the electrolytic solution tank 2. be able to. Specifically, it was calculated from the following formula.
Accumulation rate of precipitate 17 (%) = | PQ | ÷ Q × 100
In addition, the accumulation amount Q was set to an amount capable of recovering the fine particulate precipitate 17 in the electrolytic solution tank 2 without hindrance.
When the accumulation rate reaches 100%, the notification unit 27 is provided so that the display indicates that it is the discharge time.

Discharge was performed with the produced zinc-air battery. When the accumulation rate reaches 100%, it is displayed on the display as the display unit 27 that it is the discharge time. After the discharge time was displayed on the display, the precipitate 17 was discharged together with the electrolytic solution 3 from the electrolytic solution tank 2 to the collecting unit 37. And the electrolyte solution was filtered in the collection | recovery part 37, and the residue 44 and the filtrate (electrolyte solution 3) were obtained. And the electrolyte solution 3 collect | recovered as the filtrate 45 was returned to the electrolyte solution tank 2, and the discharge by a metal air battery was restarted.
Therefore, in this metal-air battery, since the discharge time of the precipitate 17 could be known, the fine particle precipitate 17 could be discharged from the electrolyte bath 2 at an appropriate time.
The accumulated amount of the precipitate 17 was reset to zero after the precipitate 17 was discharged from the electrolytic solution tank 2.

Next, as Comparative Example 3, a zinc-air battery that did not include the first measurement unit 24, the arithmetic circuit 26, the storage medium 28, and the notification unit 27 was produced. Other configurations are the same as those of the zinc-air battery of Example 3.
Discharge was performed with the produced zinc-air battery. And after discharging for 50 hours, the deposit 17 was discharged | emitted from the inside of the electrolyte tank 2 to the collection | recovery part 37 with the electrolyte solution 3, and the deposit 17 and the electrolyte solution 3 were isolate | separated. Then, the deposit 17 overflowed from the recovery part 37, and it took time until the discharge by the zinc-air battery was resumed.
In the zinc-air battery of Comparative Example 3, it is considered that the discharge timing of the precipitate 17 could not be known, and the precipitate 17 was deposited beyond the recoverable amount.

Discharge experiment 4
As a fourth embodiment, a zinc meter is provided as the first measurement unit 24, and the display as the notification unit 27 displays that the amount of the electrolyte is decreasing based on the measurement result of the pH meter. An air battery was produced. Further, a 7M KOH aqueous solution in which zinc oxide was not dissolved was used as the electrolytic solution. Other configurations are the same as those of the zinc-air battery of Example 1.
When the zinc-air battery discharges for a long time, moisture contained in the electrolyte solution in the electrolyte solution tank 2 is gradually lost, and the amount of the electrolyte solution gradually decreases. When water contained in the electrolytic solution is gradually lost, the ion concentration of the electrolytic solution is relatively increased, so that the OH ⁻ ion concentration in the electrolytic solution is also gradually increased. Accordingly, by continuously measuring the pH reflecting this OH ⁻ ion concentration, it is possible to detect a decrease in the amount of the electrolytic solution in the electrolytic solution tank 2.
In this experiment, the notification unit 27 is provided so that when the pH measured by the pH meter shows a value exceeding 15, the display indicates that the amount of the electrolyte is decreasing.
Discharge was performed with the produced zinc-air battery. And whenever the fall of the amount of electrolyte solution was displayed on the notification part 27, water was replenished in the electrolyte tank, and discharge was continued for one month.
In this zinc-air battery, the difference between the discharge capacity on the first day of discharge and the discharge capacity one month after the start of discharge was less than 5%.
Since the notification unit 27 displayed a decrease in the amount of the electrolytic solution, an appropriate amount of water could be supplied into the electrolytic solution tank 2 at an appropriate time.

Next, as Comparative Example 4, a zinc-air battery that did not include the first measurement unit 24, the arithmetic circuit 26, the storage medium 28, and the notification unit 27 was produced. Other configurations are the same as those of the zinc-air battery of Example 4.
The produced zinc-air battery was discharged for 1 month. During the discharge period, water is not replenished in the electrolyte bath.
In this zinc-air battery, the discharge capacity one month after the start of discharge was reduced by about 10% with respect to the discharge capacity on the first day of discharge. Further, the total amount of the electrolyte decreased by about 5% during the discharge period. In addition, the pH of the electrolyte one month after the start of discharge was 15.5, which was higher than usual.
The reason why the discharge capacity decreased for one month after the start of discharge is considered to be that the amount of the electrolytic solution decreased and the surface area of the metal electrode 5 in contact with the electrolytic solution decreased.

1: Housing 2: Electrolyte tank 3: Electrolyte 5: Metal electrode 7: Air electrode catalyst layer 8: Gas diffusion layer 9: Air electrode 10: Air electrode terminal 11: Metal electrode terminal 14: Separator 17: Deposit ( Spent active material) 23: Pore 24: First measurement unit 25: Second measurement unit 26: Arithmetic circuit 27: Notification unit 28: Storage medium 30: Metal-air battery 35: Valve 37: Collection unit 41: Mold member 42 : Filter medium 44: Residue 45: Filtrate 46: Electrolyte collection container

Claims

An electrolytic solution tank that contains an electrolytic solution, a metal electrode that is provided in the electrolytic solution tank and has an electrode active material and serves as an anode, an air electrode that serves as a cathode, and a first electrode that uses the electrolytic solution as a measurement target A measurement unit and / or a second measurement unit for measuring a discharge current of the metal-air battery; and a notification unit for notifying battery information based on a measurement result of the first measurement unit and / or the second measurement unit. A metal-air battery comprising:
The first measurement unit is a measurement unit that measures at least one of a pH value, conductivity, viscosity, and density related to the electrolytic solution,
2. The metal-air battery according to claim 1, wherein the battery information is information representing a dischargeable time, information representing an ion concentration of the electrolytic solution, or information representing a time when an electrolytic solution or water is supplied to the electrolytic solution tank. .
The first measurement unit is a measurement unit that measures at least an OH − ion concentration or a metal-containing ion concentration related to the electrolytic solution,
2. The metal-air battery according to claim 1, wherein the battery information is information representing a dischargeable time, information representing an ion concentration of the electrolytic solution, or information representing a time when an electrolytic solution or water is supplied to the electrolytic solution tank. .
The first measurement unit is a pH meter, an ORP meter, or a conductivity meter,
The arithmetic circuit which calculates the OH- ion concentration contained in the electrolyte based on the measurement result of the pH meter, the ORP meter, or the conductivity meter is further provided. Metal-air battery as described in 2.
The first measuring unit is a viscometer or a density meter,
3. The metal-air battery according to claim 1, further comprising an arithmetic circuit that calculates a metal-containing ion concentration contained in the electrolytic solution based on a measurement result of the viscometer or a density meter. .
The metal electrode includes at least metal zinc,
The metal-air battery according to claim 5, wherein the metal-containing ions are Zn (OH) 4 2- .
6. The metal-air battery according to claim 5, wherein the arithmetic circuit calculates an OH − ion concentration in the electrolytic solution from the metal-containing ion concentration in the electrolytic solution.
A first calibration curve showing the correlation between the pH value of the electrolytic solution and the metal-containing ion concentration in the electrolytic solution, and showing the correlation between the conductivity of the electrolytic solution and the metal-containing ion concentration in the electrolytic solution. A second calibration curve, a third calibration curve showing the correlation between the viscosity of the electrolyte and the OH − ion concentration in the electrolyte, the density of the electrolyte and the OH − ion concentration in the electrolyte A storage medium storing at least one of a fourth calibration curve indicating a correlation and a fifth calibration curve indicating a correlation between the pH, conductivity, viscosity or density of the electrolytic solution and the dischargeable time; ,
The measurement result of the first measurement unit is compared with the first calibration curve, the second calibration curve, the third calibration curve, the fourth calibration curve or the fifth calibration curve, The metal-air battery according to claim 1, further comprising an arithmetic circuit that calculates battery information.
The battery information includes information indicating the dischargeable time, information indicating the remaining amount of the electrode active material included in the metal electrode, information indicating the amount of precipitate generated from the electrode active material, or discharge of the precipitate. The metal-air battery according to claim 1, wherein the metal-air battery is information representing time.
The arithmetic circuit includes at least an OH − ion concentration in the electrolyte calculated based on a measurement result of the first measurement unit,
From the accumulated discharge capacity calculated based on the measurement result of the second measurement unit,
The metal-air battery according to claim 4 or 7, wherein a water level of the electrolytic solution stored in the electrolytic solution tank is calculated.
A storage unit that stores the amount of electrode active material M1 contained in the metal electrode before discharge;
The arithmetic circuit is:
At least the electrode active material amount M1 contained in the metal electrode before discharge,
The remaining amount of the electrode active material contained in the metal electrode is calculated from the consumption M2 of the electrode active material calculated based on the measurement result of the second measurement unit. 2. The metal-air battery according to 2.
The metal-air battery according to claim 11, wherein the calculation unit calculates a dischargeable time from at least a remaining amount of the electrode active material included in the metal electrode.
OH − ion concentration x of the electrolytic solution when the metal-containing ion concentration of the electrolytic solution becomes a saturated concentration,
And an OH − ion concentration y of the electrolytic solution when the metal-containing ion concentration of the electrolytic solution forms a passive state, further comprising a storage unit that stores at least
The information indicating the dischargeable time is calculated as the dischargeable amount by the arithmetic circuit from the OH − ion concentration x, the OH − ion concentration y stored in the storage unit, and the electrolysis calculated from the first measurement unit. The metal-air battery according to claim 4 or 7, further comprising a calculation unit that calculates a dischargeable amount from the following formula (1) from the OH - ion concentration z of the liquid.
Dischargeable amount (%) = (| y−z | ÷ | y−x |) × 100 (1)
The conductivity x of the electrolyte solution when the metal-containing ion concentration of the electrolyte solution becomes a saturated concentration, and the conductivity y of the electrolyte solution when the metal-containing ion concentration of the electrolyte solution forms a passive state And a storage unit storing at least
The information indicating the dischargeable time includes, as the dischargeable amount, the conductivity x stored in the storage unit, the conductivity y, and the conductivity of the electrolyte measured by the first measurement unit by the arithmetic circuit. The metal-air battery according to claim 2, further comprising: an arithmetic unit that calculates a dischargeable amount from the following formula (1) from z.
Dischargeable amount (%) = (| y−z | ÷ | y−x |) × 100 (1)
15. The metal-air battery according to claim 1, wherein the notification unit is a notification unit that notifies battery information to a remote place using a data communication line.