JP5773699B2 - Metal air battery - Google Patents

Description

  The present invention relates to a metal-air battery.

  Conventionally, a metal-air battery using a metal as an active material for a negative electrode layer and oxygen in the air as an active material for a positive electrode layer is known. In the metal-air battery, there is a possibility that the positive electrode layer and the negative electrode layer are short-circuited due to local deposition of metal on the negative electrode layer during charging. Thus, a method has been proposed in which a separator is provided between the positive electrode layer and the negative electrode layer to prevent a short circuit between the positive electrode layer and the negative electrode layer (see, for example, Patent Documents 1 and 2).

JP 2008-66202 A JP 2009-230981 A

  By the way, by providing an auxiliary electrode layer (that is, a third electrode) for charging in the metal-air battery, using the positive electrode layer and the negative electrode layer during discharging, and using the negative electrode layer and the auxiliary electrode layer during charging, the metal-air battery It is conceivable to improve the charging and discharging performance. However, even in such a metal-air battery, when metal is locally deposited on the negative electrode layer during charging, the negative electrode layer and the auxiliary electrode layer may be short-circuited.

  This invention is made | formed in view of the said subject, and aims at preventing that a negative electrode layer and an auxiliary electrode layer short-circuit.

The invention according to claim 1 is a metal-air battery, comprising a metal-containing negative electrode layer, a conductive material, and a porous positive electrode layer containing a catalyst that promotes an oxygen reduction reaction, the negative electrode layer, and the A first electrolyte layer disposed between the positive electrode layer, an auxiliary electrode layer having a surface facing the surface of the negative electrode layer opposite to the positive electrode layer, and between the negative electrode layer and the auxiliary electrode layer And the second electrolyte layer communicating with the first electrolyte layer, the positive electrode layer, the negative electrode layer, and the auxiliary electrode layer are cylindrical, and the surface of the negative electrode layer is the auxiliary electrode layer A portion that spreads outward from a portion that faces the edge portion of the surface, and a voltage is applied between the negative electrode layer and the auxiliary electrode layer during charging so that the metal is formed on the negative electrode layer. Precipitates.

According to a second aspect of the invention, a metal-air battery according to claim 1, which before Symbol positive electrode layer is disposed inside the negative electrode layer, the auxiliary electrode layer is disposed on the outside of the negative electrode layer .

The invention according to claim 3, a metallic air battery, Ri multi porosifying member der, a negative electrode layer containing a metal, conductive material, and, a porous comprising a catalyst that promotes oxygen reduction reaction A positive electrode layer; a first electrolyte layer disposed between the negative electrode layer and the positive electrode layer; an auxiliary electrode layer having a surface facing the surface of the negative electrode layer opposite to the positive electrode layer; and the negative electrode A second electrolyte layer disposed between the layer and the auxiliary electrode layer and communicating with the first electrolyte layer, wherein the surface of the negative electrode layer faces an edge portion of the surface of the auxiliary electrode layer has a region extending from the site to the outside, it said metal deposited on the negative electrode layer when a voltage is applied in between the anode layer and the auxiliary electrode layer during charging.

  The invention according to claim 4 is the metal-air battery according to any one of claims 1 to 3, wherein the conductive material is a perovskite oxide and the positive electrode layer does not contain carbon.

  According to the present invention, it is possible to prevent a short circuit between the negative electrode layer and the auxiliary electrode layer.

It is a longitudinal cross-sectional view which shows a metal air battery. It is a cross-sectional view showing a metal-air battery. It is a figure which shows the negative electrode layer and auxiliary electrode layer in the metal air battery of a comparative example. It is a figure which shows the negative electrode layer and auxiliary electrode layer in the metal air battery of another comparative example. It is a figure which shows a negative electrode layer and an auxiliary electrode layer.

  FIG. 1 is a longitudinal sectional view showing a metal-air battery 1 according to an embodiment of the present invention. The metal-air battery 1 has a substantially cylindrical shape, and FIG. 1 shows a cross section including the central axis J1 of the metal-air battery 1. FIG. 2 is a cross-sectional view of the metal-air battery 1 cut at the position AA in FIG. As shown in FIGS. 1 and 2, the metal-air battery 1 is a secondary battery including a positive electrode layer 2, a negative electrode layer 3, and an electrolyte layer 11. The metal-air battery 1 further includes an air introduction tube 5, another electrolyte layer 12, and an auxiliary electrode layer 4, and the air introduction tube 5, the positive electrode layer 2, and the electrolyte layer 11 from the central axis J <b> 1 outward in the radial direction. The negative electrode layer 3, the electrolyte layer 12, and the auxiliary electrode layer 4 are arranged concentrically in order. In the following description, the electrolyte layer 11 between the positive electrode layer 2 and the negative electrode layer 3 is referred to as a first electrolyte layer 11, and the electrolyte layer 12 between the negative electrode layer 3 and the auxiliary electrode layer 4 is referred to as a second electrolyte layer 12. Call.

  The positive electrode layer 2 is a substantially bottomed cylindrical porous member, each of which has a substantially bottomed cylindrical positive electrode conductive layer 22 and a positive electrode catalyst layer 23, and a liquid repellency with respect to an electrolyte described later (this embodiment) Then, a porous liquid repellent layer 21 having water repellency with respect to an aqueous electrolyte is provided. Specifically, in the metal-air battery 1, a substantially bottomed cylindrical positive electrode support portion 61 centering on the central axis J1 is provided, and the liquid repellent layer 21 is laminated on the outer surface and the outer bottom surface of the positive electrode support portion 61. Is done. The positive electrode conductive layer 22 is laminated on the outer side surface and the outer bottom surface of the liquid repellent layer 21, and the positive electrode catalyst layer 23 is laminated on the outer side surface and the outer bottom surface of the positive electrode conductive layer 22. In the positive electrode layer 2, a positive electrode current collector 24 is provided on a part of the outer surface of the positive electrode conductive layer 22 instead of the positive electrode catalyst layer 23, and the positive electrode current collector 24 is disposed at the upper end of the positive electrode current collector 24 as shown in FIG. The electric terminal 25 is connected. Preferably, the positive electrode layer 2 (that is, the liquid repellent layer 21, the positive electrode conductive layer 22, the positive electrode catalyst layer 23, and the positive electrode current collector 24) does not contain carbon (C).

The positive electrode support 61 is a porous member formed of a ceramic such as alumina (aluminum oxide: Al ₂ O ₃ ) or zirconia, or a metal such as stainless steel. In this embodiment, the positive electrode support 61 Is formed of alumina as an insulator. The positive electrode support 61 is formed by extrusion molding, CIP (Cold Isostatic Press) and firing, or HIP (Hot Isostatic Press).

The positive electrode conductive layer 22 is a porous thin conductive film mainly formed of a conductive perovskite oxide (usually in powder form), and preferably has a chemical formula A _1-x BO ₃ (0.9 It is formed of a perovskite oxide represented by ≦ 1-x <1.0). In the present embodiment, the positive electrode conductive layer 22 includes a lanthanum perovskite oxide (specifically, lanthanum strontium manganite (LSM: La (Sr) MnO ₃ ) or lanthanum strontium cobaltite (LSC: La (Sr) A perovskite oxide containing lanthanum at the A site such as CoO ₃ ). The positive electrode conductive layer 22 is formed by a slurry coating method, a hydrothermal synthesis method, CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), or the like.

The positive electrode catalyst layer 23 is a porous member mainly formed of a metal oxide such as manganese (Mn), nickel (Ni), or cobalt (Co) that is a catalyst for promoting an oxygen reduction reaction. The positive electrode catalyst layer 23 is formed of a noble metal such as platinum (Pt), palladium (Pd), silver (Ag), rhodium (Rh), ruthenium (Ru), or a mixture of these noble metals and the above metal oxide. May be. In the present embodiment, the positive electrode catalyst layer 23 is formed of manganese dioxide (MnO ₂ ) having a β-type (rutile-type) crystal structure. The positive electrode catalyst layer 23 is formed by a slurry coating method and baking, a hydrothermal synthesis method, CVD, PVD, or the like.

Further, the liquid repellent layer 21 disposed between the positive electrode support 61 and the positive electrode conductive layer 22 is formed of a material having water repellency, and has a high heat resistance when the temperature is high when the positive electrode conductive layer 22 is formed. A ceramic material having a property (for example, oxide ceramic) is used. In the present embodiment, a porous film formed of silica (silicon dioxide: SiO ₂ ) or a silica composite material is used as the liquid repellent layer 21. Depending on the design of the metal-air battery 1, a porous member that does not have water repellency may have a saturated fluoroalkyl group (particularly, a trifluoromethyl group (CF ₃ ⁻ )), an alkylsilyl group, a fluorosilyl group, or a long-chain alkyl group. The liquid repellent layer 21 may be formed by coating a substance having a functional group such as a group.

  As shown in FIGS. 1 and 2, the negative electrode layer 3 includes a cylindrical negative electrode conductive layer 31 disposed outside the cylindrical positive electrode layer 2. The negative electrode current collection terminal 32 is provided as shown in FIG. The negative electrode conductive layer 31 is a porous member formed of a metal such as zinc (Zn) or lithium (Li), or an alloy containing the metal. In the present embodiment, the negative electrode conductive layer 31 is zinc or zinc. It is formed from an alloy.

  The auxiliary electrode layer 4 that is the third electrode for charging includes a cylindrical auxiliary conductive layer 42 disposed outside the cylindrical negative electrode layer 3. The auxiliary conductive layer 42 is a porous member formed of a conductive material such as metal (in this embodiment, stainless steel). As shown in FIG. 1, the metal-air battery 1 is provided with an auxiliary electrode support portion 71 formed of an insulating material. The auxiliary electrode support portion 71 includes a cylindrical upper support portion 711 and a bottomed cylindrical lower support portion 712, and the auxiliary conductive layer 42, the upper support portion 711, and the lower support portion 712 have the same diameter. . The upper end portion of the auxiliary conductive layer 42 is fixed to the upper support portion 711, and the lower end portion is fixed to the lower support portion 712. In the metal-air battery 1, the auxiliary conductive layer 42 and the auxiliary electrode support portion 71 form a bottomed cylindrical container that accommodates the positive electrode layer 2, the negative electrode layer 3, the first electrolyte layer 11, and the second electrolyte layer 12. Is done. In addition, the up-down direction (center axis J1 direction) of FIG. 1 is not necessarily a gravity direction.

  The inner side surface 40 of the auxiliary conductive layer 42 is disposed at a uniform interval with respect to the outer side surface 30 of the negative electrode conductive layer 31 opposite to the positive electrode layer 2. That is, the distance (shortest distance) from each position on the inner side surface 40 of the auxiliary conductive layer 42 to the outer side surface 30 of the negative electrode conductive layer 31 is approximately equal over the entire inner side surface 40. An auxiliary electrode current collecting terminal 43 is connected to the outer surface of the auxiliary conductive layer 42, and a liquid repellent layer 41 similar to the liquid repellent layer 21 is formed over the entire outer surface.

  The first electrolyte layer 11 is formed of an aqueous electrolyte. In the present embodiment, the first electrolyte layer 11 is an electrolytic solution containing potassium hydroxide (KOH) (for example, an 8M-KOH aqueous solution in which 8 mol of KOH is dissolved per liter of water). The electrolytic solution is also called an electrolytic solution.) Is filled (arranged) between the positive electrode layer 2 and the negative electrode layer 3. The first electrolyte layer 11 is in contact with the positive electrode catalyst layer 23 of the positive electrode layer 2, the positive electrode current collector 24, and the negative electrode conductive layer 31 of the negative electrode layer 3. As shown in FIG. 1, the upper surface of the first electrolyte layer 11 is closed by a substantially annular inner lid 51 in contact with the outer side surface of the positive electrode support portion 61 and the inner side surface of the auxiliary electrode support portion 71. The upper lid 52 having the same shape as the inner lid 51 is provided to close the opening above the inner lid 51. Note that the electrolytic solution contained in the first electrolyte layer 11 may be another aqueous electrolytic solution or a non-aqueous (for example, organic solvent based) electrolytic solution.

  The second electrolyte layer 12 between the negative electrode layer 3 and the auxiliary electrode layer 4 has a porous member 121 formed of ceramic, an inorganic material, an organic material, or the like. The porous member 121 is formed by extrusion molding, CIP, and firing. Or by a method such as HIP. As shown in FIG. 1, the second electrolyte layer 12 and the first electrolyte layer 11 communicate with each other through the gap between the lower end portion of the negative electrode conductive layer 31 and the lower support portion 712, and the porous member 121 The aqueous electrolyte solution of the first electrolyte layer 11 is impregnated in the hole. That is, the electrolyte solution is filled also in the second electrolyte layer 12.

  The air introduction tube 5 is disposed inside the substantially bottomed cylindrical positive electrode support portion 61, and the lower end of the air introduction tube 5 is positioned near the bottom portion of the positive electrode support portion 61. The upper end of the air introduction pipe 5 is connected to a removal unit 53 that removes moisture and carbon dioxide from the air. The removing unit 53 removes moisture and carbon dioxide in the air by membrane separation or adsorption. Air from the removal unit 53 (that is, air from which moisture and carbon dioxide have been removed) is guided to the vicinity of the bottom inside the positive electrode support 61 by the air introduction tube 5, and the positive electrode support 61 is a porous member. While being supplied to the positive electrode layer 2 through the side portion, the positive electrode support portion 61 rises along the inner surface and is discharged from the upper opening of the positive electrode support portion 61 to the outside. In the metal-air battery 1, the air introduction tube 5 serves as a gas supply unit that supplies the air from the removal unit 53 to the positive electrode layer 2. The air supplied to the positive electrode layer 2 passes through the liquid repellent layer 21 and the positive electrode conductive layer 22 which are porous members, and is supplied to the positive electrode catalyst layer 23. In the metal-air battery 1, in principle, an interface between air and an electrolytic solution is formed in the porous positive electrode catalyst layer 23.

  In the metal-air battery 1 of FIGS. 1 and 2, for example, the diameter of the outer surface of the positive electrode layer 2 is 16 mm (millimeters), the diameter of the inner surface of the negative electrode layer 3 is 20 mm, and the outer surface 30 of the negative electrode layer 3. The diameter of the inner surface 40 of the auxiliary electrode layer 4 is 28 mm. The distance between the positive electrode layer 2 and the negative electrode layer 3 (thickness of the first electrolyte layer 11) and the distance between the negative electrode layer 3 and the auxiliary electrode layer 4 (thickness of the second electrolyte layer 12) are 4 mm or less. (1 mm or more) is preferable.

When discharge is performed in the metal-air battery 1 of FIG. 1, the negative electrode current collector terminal 32 and the positive electrode current collector terminal 25 are electrically connected via a load (for example, a lighting fixture or the like). In the negative electrode layer 3, the metal contained in the negative electrode conductive layer 31 is oxidized to generate metal ions (here, zinc ions (Zn ²⁺ )). The positive electrode layer 2 is supplied via the electric body 24. In the positive electrode layer 2, oxygen in the air supplied from the air introduction tube 5 is reduced by electrons supplied from the negative electrode layer 3 to generate oxygen ions (O ²⁻ ). In the positive electrode layer 2, since the production of oxygen ions (that is, the oxygen reduction reaction) is promoted by the positive electrode catalyst contained in the positive electrode catalyst layer 23, the overvoltage due to the energy consumed in the reduction reaction is reduced, and the metal-air battery 1 discharge voltage can be increased. The oxygen ions generated in the positive electrode layer 2 are combined with the metal ions dissolved in the first electrolyte layer 11 from the negative electrode layer 3, thereby generating a metal oxide.

On the other hand, when charging is performed in the metal-air battery 1, a voltage is applied between the negative electrode current collector terminal 32 and the auxiliary electrode current collector terminal 43, that is, between the negative electrode layer 3 and the auxiliary electrode layer 4, In the auxiliary electrode layer 4, the metal oxide is decomposed, and electrons are supplied from the oxygen ions to the auxiliary electrode collector terminal 43 to generate oxygen. In the negative electrode layer 3, metal ions are reduced by the electrons supplied to the negative electrode current collector terminal 32, and metal is deposited on the surface (outer surface 30) of the negative electrode conductive layer 31. The current density between the auxiliary electrode layer 4 and the negative electrode layer 3 during charging is, for example, 70 [mA / cm ² ]. Actually, a minute gap exists between the porous member 121 of the second electrolyte layer 12 and the negative electrode layer 3, and for the reason described later, the outer surface 30 of the negative electrode conductive layer 31 is approximately in the gap. The metal is deposited almost uniformly throughout. Note that oxygen generated in the auxiliary electrode layer 4 is discharged to the outside through the porous auxiliary conductive layer 42 and the liquid repellent layer 41.

  By the way, the positive electrode layer of a normal metal-air battery is mainly composed of carbon for obtaining conductivity, and a positive electrode catalyst for promoting a reduction reaction of oxygen is added to the carbon. However, in such a metal-air battery, metal ions generated at the time of discharge are deposited as a metal carbonate on the positive electrode layer, and the metal-air battery is deteriorated.

On the other hand, in the metal-air battery 1 according to the present embodiment, the positive electrode layer 2 containing no carbon is realized by forming the positive electrode catalyst layer 23 on the positive electrode conductive layer 22 formed of the perovskite oxide. can do. Thereby, it can prevent that metal carbonate is produced | generated on the positive electrode layer 2 in the case of discharge. Further, since the positive electrode conductive layer 22 contains a highly conductive lanthanum perovskite oxide, the discharge voltage of the metal-air battery 1 can be increased. Further, the perovskite oxide contained in the positive electrode conductive layer 22 is represented by the chemical formula A _1-x BO ₃ (0.9 ≦ 1-x <1.0), whereby the positive electrode conductive layer 22 It is possible to prevent deterioration due to moisture and improve the durability of the metal-air battery 1.

  In the metal-air battery 1, since the positive electrode conductive layer 22 of the positive electrode layer 2 is a thin conductive film supported (supported) by the positive electrode support portion 61, the amount of relatively expensive perovskite oxide can be reduced. it can. As a result, the manufacturing cost of the metal-air battery 1 can be reduced. In addition, when air from which carbon dioxide has been removed is supplied to the positive electrode layer 2 by the air introduction pipe 5, carbon dioxide in the air reacts with metal ions, and metal carbonate adheres to the positive electrode layer 2. Is prevented.

  Next, the relationship between the negative electrode layer and the auxiliary electrode layer in the metal-air battery will be described. FIG. A and FIG. B is a diagram showing a negative electrode layer and an auxiliary electrode layer in a metal-air battery of a comparative example, and is a diagram corresponding to the negative electrode layer 3 and the auxiliary electrode layer 4 on the left side of the central axis J1 in FIG. FIG. A and FIG. In B, only the negative electrode layers 91a and 91b and the auxiliary electrode layers 92a and 92b are illustrated, and the direction of the electric field at the time of charging is indicated by an arrow with reference numeral 90.

  FIG. As shown in A, when the vertical length of the auxiliary electrode layer 92a is made longer than that of the negative electrode layer 91a, the current density between the auxiliary electrode layer 92a and the upper end portion and the lower end portion of the negative electrode layer 91a is increased. , Current concentration occurs. In this case, there is a possibility that the metal in the electrolytic solution is unevenly deposited at the upper end and the lower end of the negative electrode layer 91a, and the auxiliary electrode layer 92a and the negative electrode layer 91a are short-circuited. In addition, FIG. As shown in B, even when the vertical length of the auxiliary electrode layer 92b is made equal to that of the negative electrode layer 91b, current concentration occurs at the upper end portion and the lower end portion of the negative electrode layer 91b, and the metal is unevenly deposited. End up.

  On the other hand, in the metal-air battery 1, as shown in FIG. 4, the vertical length of the auxiliary electrode layer 4 (the auxiliary conductive layer 42) is shorter than that of the negative electrode layer 3 (the negative electrode conductive layer 31). 1, the area of the outer surface 30 of the negative electrode layer 3 disposed on the inner side is larger than the area of the inner surface 40 of the auxiliary electrode layer 4 disposed on the outer side. In other words, the inner side surface 40 of the auxiliary electrode layer 4 and the outer side surface 30 of the negative electrode layer 3 are respectively referred to as the auxiliary facing surface 40 and the negative electrode facing surface 30, and the negative electrode facing surface 30 is the edge portion of the auxiliary facing surface 40 (in FIG. It has the part 301,302 which spreads outside from the part which opposes the upper end part 401 and the lower end part 402) of the opposing surface 40. As shown in FIG. This prevents the current density between the upper electrode layer 4 and the auxiliary electrode layer 4 from increasing at the upper end and the lower end of the negative electrode layer 3 during charging. As a result, the metal can be deposited almost uniformly on the negative electrode facing surface 30 of the negative electrode layer 3 (a metal is prevented from being deposited locally), and the negative electrode layer 3 and the auxiliary electrode layer 4 are short-circuited. Can be prevented.

  Further, since the negative electrode layer 3 is a porous member, the metal is easily deposited in the active pores, and the metal is deposited on the negative electrode layer 3 in a dendritic manner (so-called dendrite generation) is suppressed. be able to. Furthermore, in the auxiliary electrode layer 4 formed of stainless steel, generation of carbon dioxide can be suppressed when charging is performed using an electrode formed of carbon.

  In the metal-air battery 1, the liquid repellent layer 21 having liquid repellency with respect to the electrolyte contained in the first electrolyte layer 11 is on the side opposite to the first electrolyte layer 11 with respect to the positive electrode conductive layer 22 and the positive electrode catalyst layer 23. By being provided, even if the electrolytic solution permeates (passes) the positive electrode catalyst layer 23 and the positive electrode conductive layer 22, the electrolytic solution leaks inside the positive electrode support portion 61 (that is, in the vicinity of the air introduction pipe 5). Can be prevented. Furthermore, since the liquid repellent layer 21 is a porous member, it is possible to prevent the electrolyte from leaking (leakage) while allowing air to be supplied to the positive electrode conductive layer 22 and the positive electrode catalyst layer 23.

  In the auxiliary electrode layer 4, the liquid repellent layer 41, which is liquid-repellent with respect to the electrolytic solution and is a porous member, is provided on the surface of the auxiliary conductive layer 42 opposite to the second electrolyte layer 12. While allowing air to be supplied to the layer 42, it is possible to prevent the electrolyte from leaking outside the auxiliary electrode layer 4.

Depending on the design of the metal-air battery 1, inorganic fine particles (filler) may be added to the aqueous electrolytes of the first and second electrolyte layers 11 and 12. As the inorganic fine particles, inorganic oxides such as alumina, silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), zeolite, and perovskite oxide are preferable, and the Si ratio is particularly high (for example, Si / Al is 2 or more). Zeolite particles are preferred. When the electrolytic solution of the first electrolyte layer 11 contains inorganic fine particles, the internal resistance of the metal-air battery 1 is reduced, the battery capacity is increased, and leakage from the metal-air battery 1 is prevented.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  A solid electrolyte may be used in the first and second electrolyte layers 11 and 12. Further, the liquid repellent layer only needs to be provided as necessary, and can be omitted, for example, when a solid electrolyte is used. The negative electrode conductive layer 31 of the negative electrode layer 3 may be formed of various materials including a metal that is oxidized during discharge to generate (release) metal ions.

  In the positive electrode layer 2, when the positive electrode support 61 and the liquid repellent layer 21 are formed of a conductive material, the positive electrode current collector 24 is omitted and the positive electrode current collector terminal 25 is provided on the inner surface of the positive electrode support 61. It's okay. When the positive electrode conductive layer 22 has a certain thickness, the positive electrode support portion 61 that supports the positive electrode conductive layer 22 may be omitted. In this case, the positive electrode current collecting terminal 25 is provided on the inner surface of the positive electrode conductive layer 22.

  In the metal-air battery, a conductive layer is formed from a mixture of the material of the positive electrode support 61 and the material of the positive electrode conductive layer 22 (that is, a perovskite oxide), and the positive electrode catalyst layer 23 is formed on the conductive layer. And may be the positive electrode layer 2. Further, the positive electrode layer 2 may be formed from a mixture of the positive electrode support portion 61, the positive electrode conductive layer 22, and the positive electrode catalyst layer 23. In any case, since the positive electrode layer 2 contains a perovskite oxide having conductivity and a catalyst that promotes an oxygen reduction reaction and does not contain carbon, the metal-air battery is discharged at the time of discharge. The metal carbonate contained in the negative electrode layer 3 can be prevented from being formed on the positive electrode layer 2. In the case where generation of metal carbonate does not become a problem, the positive electrode conductive layer 22 may be formed of another conductive material.

  The structure of the metal-air battery described above may be applied to, for example, a flat metal-air battery. Also in this case, the negative electrode facing surface and the auxiliary facing surface face each other, and the negative electrode facing surface spreads outward from the portion facing the edge portion of the auxiliary facing surface (that is, in the normal direction of both surfaces parallel to each other) The metal is locally deposited on the negative electrode layer at the time of charging by having a part extending from the part on the negative electrode facing surface that overlaps the edge part to the outside of the edge part along the direction perpendicular to the normal line) Is prevented. As described above, the metal-air battery capable of preventing a short circuit between the negative electrode layer and the auxiliary electrode layer can be realized in various shapes. However, when the positive electrode layer, the negative electrode layer, and the auxiliary electrode layer are cylindrical, the active and easy-to-dendrite edge portions can be reduced compared to the flat plate shape (that is, the edge portions are only at the upper and lower ends). It is possible to further suppress the generation of dendrite.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Metal-air battery 2 Positive electrode layer 3 Negative electrode layer 4 Auxiliary electrode layer 11 1st electrolyte layer 12 2nd electrolyte layer 22 Positive electrode conductive layer 23 Positive electrode catalyst layer 30 Negative electrode opposing surface 40 Auxiliary opposing surface 301,302 (Expanded outside) 401 Upper end 402 Lower end

Claims (4)

A metal-air battery,
A negative electrode layer containing a metal;
A porous positive electrode layer including a conductive material and a catalyst for promoting an oxygen reduction reaction;
A first electrolyte layer disposed between the negative electrode layer and the positive electrode layer;
An auxiliary electrode layer having a surface facing the surface of the negative electrode layer opposite to the positive electrode layer;
A second electrolyte layer disposed between the negative electrode layer and the auxiliary electrode layer and communicating with the first electrolyte layer;
With
The positive electrode layer, the negative electrode layer, and the auxiliary electrode layer are cylindrical,
The surface of the negative electrode layer has a portion that spreads outward from a portion facing the edge portion of the surface of the auxiliary electrode layer;
The metal-air battery, wherein the metal is deposited on the negative electrode layer by applying a voltage between the negative electrode layer and the auxiliary electrode layer during charging. The metal-air battery according to claim 1,
Before SL positive electrode layer is disposed on the inner side of the negative electrode layer, a metal-air battery, characterized in that said auxiliary electrode layer is disposed on the outside of the negative electrode layer. A metallic air battery,
Porous member der is, a negative electrode layer containing a metal,
A porous positive electrode layer including a conductive material and a catalyst for promoting an oxygen reduction reaction;
A first electrolyte layer disposed between the negative electrode layer and the positive electrode layer;
An auxiliary electrode layer having a surface facing the surface of the negative electrode layer opposite to the positive electrode layer;
A second electrolyte layer disposed between the negative electrode layer and the auxiliary electrode layer and communicating with the first electrolyte layer;
With
The surface of the negative electrode layer has a portion that spreads outward from a portion facing the edge portion of the surface of the auxiliary electrode layer;
The metal-air battery, characterized that you said metal deposited on the negative electrode layer when a voltage is applied in between the negative electrode layer and the auxiliary electrode layer during charging. The metal-air battery according to any one of claims 1 to 3,
The metal-air battery, wherein the conductive material is a perovskite oxide and the positive electrode layer does not contain carbon.

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