阅读说明：本技术 金属空气电池以及金属空气电池的极间距离设定方法 (Metal-air battery and method for setting inter-electrode distance of metal-air battery ) 是由 小出彩乃 松山龙次 于 2019-04-03 设计创作，主要内容包括：高效地获得高性能的金属空气电池。金属空气电池(10)具备金属电极(15)、以及与金属电极(15)相对的空气电极(13A、13B),其中,空气电极(13A、13B)分别配置在金属电极(15)的两侧,金属电极(15)配置在靠近两侧的空气电极(13A、13B)中的任意一方的位置,从金属电极(15)和一方的空气电极(13A)以极间距离(LA)配置的第1电池获得的电压与从金属电极(15)和另一方的空气电极(13B)以极间距离(LB)配置的第2电池获得的电压的平均值高于将金属电极(15)配置在两侧的空气电极(13A、13B)的中央位置的情况下获得的电压。(A high-performance metal-air battery is efficiently obtained. The metal-air battery (10) is provided with a metal electrode (15) and air electrodes (13A, 13B) opposite to the metal electrode (15), wherein the air electrodes (13A, 13B) are respectively arranged on both sides of the metal electrode (15), the metal electrode (15) is arranged at a position close to either one of the air electrodes (13A, 13B) on both sides, and the average value of the voltage obtained from a1 st battery in which the metal electrode (15) and one air electrode (13A) are arranged with an inter-electrode distance (LA) and the voltage obtained from a2 nd battery in which the metal electrode (15) and the other air electrode (13B) are arranged with an inter-electrode distance (LB) is higher than the voltage obtained when the metal electrode (15) is arranged at the center position of the air electrodes (13A, 13B) on both sides.)

1. A metal-air battery comprising a metal electrode and an air electrode facing the metal electrode,

the air electrodes are respectively arranged at two sides of the metal electrode,

the metal electrode is disposed at a position close to either one of the air electrodes on both sides,

a1 st distance as an inter-electrode distance between the metal electrode and one of the air electrodes and a2 nd distance as an inter-electrode distance between the metal electrode and the other of the air electrodes satisfy a condition that an average value of a voltage obtained from a1 st cell in which the metal electrode and one of the air electrodes are arranged at the 1 st distance and a voltage obtained from a2 nd cell in which the metal electrode and the other of the air electrodes are arranged at the 2 nd distance is higher than a voltage obtained in a case where the metal electrode is arranged at a center position of the air electrodes on both sides.

2. The metal-air cell of claim 1,

when the shorter inter-electrode distance is a value LA and the longer inter-electrode distance is a value LB, the value (LB/LA) is 2 or more.

3. Metal-air battery according to any of claims 1 or 2,

the battery pack includes a support member that supports the metal electrode so as to be spaced apart from a bottom plate portion of a battery case that houses the metal electrode.

4. A method for setting an inter-electrode distance of a metal-air battery,

the metal-air battery includes a metal electrode and an air electrode opposed to the metal electrode,

the air electrodes are respectively arranged at two sides of the metal electrode,

the metal electrode is disposed at a position close to either one of the air electrodes on both sides,

according to a nonlinear characteristic representing a relationship between the inter-electrode distance and the voltage, a1 st distance, which is the inter-electrode distance between the metal electrode and one of the air electrodes, and a2 nd distance, which is the inter-electrode distance between the metal electrode and the other of the air electrodes, are set such that an average value of a voltage obtained from a1 st cell in which the metal electrode and one of the air electrodes are arranged at the 1 st distance and a voltage obtained from a2 nd cell in which the metal electrode and the other of the air electrodes are arranged at the 2 nd distance is higher than a voltage obtained in a case where the metal electrode is arranged at a center position of the air electrodes on both sides.

Technical Field

The present invention relates to a metal-air battery and a method for setting an inter-electrode distance of the metal-air battery.

Background

In general, in a metal-air battery, an air electrode as a positive electrode and a metal electrode as a negative electrode are present in pairs. Further, a structure has been proposed in which air electrodes are disposed at equal distances on both sides of a metal electrode (fuel electrode) in a metal-air battery (see, for example, patent document 1).

Disclosure of Invention

Problems to be solved by the invention

However, since the metal-air battery mainly reacts on the surface of the air electrode facing the metal electrode, in the case of a structure in which the air electrode faces only one surface of the metal electrode, the reaction area per cell is limited, and there is a limitation in improving the battery performance. For example, the degree of polarization of the electrode tends to increase as a result of an increase in current density when a current flows.

On the other hand, in the structure of patent document 1, the current density is reduced by enlarging the air electrode area per cell, and as a result, the degree of electrode polarization is reduced. However, batteries with higher performance are desired in the market, and particularly, for metal air batteries used in disaster situations, applications for charging smart phones and the like that can be charged with high current are desired. That is, the metal-air battery needs to further reduce electrode polarization.

Therefore, an object of the present invention is to efficiently obtain a high-performance metal-air battery.

Means for solving the problems

The present specification includes the entire contents of japanese patent application No. 2018-078517 filed on 16/4/2018.

In order to solve the above problems, a metal-air battery of the present invention includes a metal electrode and an air electrode facing the metal electrode, wherein the air electrodes are disposed on both sides of the metal electrode, the metal electrode is disposed at a position close to one of the air electrodes on both sides, and a1 st distance as an inter-electrode distance between the metal electrode and one of the air electrodes and a2 nd distance as an inter-electrode distance between the metal electrode and the other of the air electrodes satisfy the following condition, that is, the average value of the voltage obtained from the 1 st cell in which the metal electrode and the one air electrode are arranged at the 1 st distance and the voltage obtained from the 2 nd cell in which the metal electrode and the other air electrode are arranged at the 2 nd distance is higher than the voltage obtained when the metal electrode is arranged at the center of the air electrodes on both sides.

In the above configuration, when the shorter one of the inter-electrode distances is a value LA and the longer one of the inter-electrode distances is a value LB, the value (LB/LA) may be 2 or more.

In the above configuration, the battery pack may further include a support member that supports the metal electrode so as to be spaced apart from the bottom plate portion of the battery case that houses the metal electrode.

In addition, in the method of setting the inter-electrode distance of the metal-air battery including the metal electrode and the air electrode opposed to the metal electrode, the air electrode being disposed on both sides of the metal electrode, respectively, and the metal electrode being disposed at a position close to either one of the air electrodes on both sides, the method is characterized in that, in accordance with a nonlinear characteristic indicating a relationship between the inter-electrode distance and a voltage, a1 st distance as the inter-electrode distance between the metal electrode and one of the air electrodes and a2 nd distance as the inter-electrode distance between the metal electrode and the other of the air electrodes are set so that an average value of a voltage obtained from a1 st cell in which the metal electrode and the one of the air electrodes are disposed at the 1 st distance and a voltage obtained from a2 nd cell in which the metal electrode and the other of the air electrodes are disposed at the 2 nd distance is higher than an average value of voltages obtained from a2 nd cell in which the metal electrode and the other of the air electrode are disposed The voltage obtained with the central position of the air electrode.

Effects of the invention

According to the present invention, a high voltage can be easily obtained while ensuring a capacity, and a high-performance metal-air battery can be efficiently obtained.

Drawings

Fig. 1 is a perspective view of a metal-air battery according to an embodiment of the present invention.

Fig. 2 is a longitudinal sectional view a-a of fig. 1.

Fig. 3 (a) is a diagram showing example 1, fig. 3 (B) is a diagram showing comparative example 1, and fig. 3 (C) is a diagram showing comparative example 2.

Fig. 4 is a graph showing the results of the capacity tests of example 1, comparative example 1, and comparative example 2.

Fig. 5 is a graph showing the results of an electrode polarization test for each combination of the inter-electrode distances LA, LB.

Fig. 6 is a graph showing the results of the constant current discharge test for each combination of the inter-electrode distances LA, LB.

Fig. 7 is a graph showing the nonlinear characteristic of the relationship between the inter-electrode distance [ mm ] and the voltage [ V ].

Fig. 8 is a graph showing the results of the electrode polarization test for each combination of the other inter-electrode distances LA, LB.

Fig. 9 is a graph showing the results of the constant current discharge test of each combination shown in fig. 8.

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a perspective view of a metal-air battery 10 according to an embodiment of the present invention, and fig. 2 is a longitudinal sectional view a-a of fig. 1.

The metal-air battery 10 is a primary battery, and includes: a battery case 11 (also referred to as a battery) is provided with two air electrodes 13A and 13B and one metal electrode 15 in the battery case 11, and power generation is started by injecting an electrolyte into the battery case 11. During power generation, the air electrodes 13A and 13B function as positive electrodes, and the metal electrode 15 functions as a negative electrode. In fig. 2, reference symbol UL denotes the position of the upper surface of the electrolyte injected into the battery case 11.

The material of the battery container 11 is not particularly limited, and paper or resin, for example, may be used. In the case where paper is used as the battery case 11, a sheet in which a film is provided on the surface of the paper constituting the base material is used, and as a specific example, a laminated paper whose inner surface is laminated with a hot-melt resin (for example, Polyethylene (PE)) can be used. By performing the lamination process, leakage of the electrolytic solution and the like can be prevented.

In the present description, the respective directions such as up, down, left, and right correspond to the directions in which the metal-air battery 10 is used, and the reference numeral X, the reference numeral Y, and the reference numeral Z in fig. 1 and the like denote the front, the right, and the upper, respectively. The X direction coincides with the arrangement direction of the air electrode 13A, the metal electrode 15, and the air electrode 13B. In addition, the installation direction may be changed depending on the use situation.

The battery case 11 is a thin rectangular parallelepiped shape, and integrally includes the following portions by bending a sheet containing paper: a bottom plate portion 21 that constitutes a bottom surface of the battery case 11; a front wall portion 22 constituting a front surface; a rear wall portion 23 constituting a rear surface; left and right side wall portions (left and right wall portions) 24 that constitute left and right side surfaces; and an upper plate portion 25 constituting an upper surface.

The front wall 22 and the rear wall 23 are surfaces having the same shape, are arranged parallel to each other, form the largest surface of the battery case 11, and have rectangular openings 22K having the same shape and size. The opening 22K of the front wall 22 is covered with the rectangular air electrode 13A, and the opening 22K of the rear wall 23 is covered with the rectangular air electrode 13B.

The air electrodes 13A and 13B are formed in the same shape and the same size, and are disposed on both sides of the metal electrode 15. Each of the air electrodes 13A and 13B is a member having air permeability that allows outside air to pass through the battery can 11 and liquid impermeability that prevents electrolyte from leaking, and for example, each of the air electrodes 13A and 13B is integrally formed by pressing (punching) a catalyst sheet or the like constituting a catalyst layer on both surfaces of a rectangular copper mesh constituting a current collector.

The air electrodes 13A and 13B are exposed in the battery case 11 through the opening 22K provided in the battery case 11, and the regions of the air electrodes 13A and 13B in the opening 22K substantially function as the air electrodes 13A and 13B. In addition, the liquid-impermeable sheet may be provided separately to ensure liquid-impermeability. The air electrodes 13A and 13B are not limited to the above configuration, and a known configuration can be widely applied.

The current collector is a porous current collector, and has good gas permeability by forming a copper mesh (copper mesh) in a rectangular shape. The current collector is not limited to copper, and may be other metals such as iron, nickel, and brass. Further, the porous structure is not limited to the porous structure formed of a net (mesh body), and a porous structure having air permeability other than the net can be widely used. The copper mesh is particularly preferable in view of both battery characteristics and cost.

The catalyst sheet is produced by sandwiching a paste obtained by kneading a conductive agent and an organic binder with water between films made of polyethylene terephthalate (PET) (hereinafter referred to as PET films), pressing the paste into a sheet by a roll press, and drying the sheet.

As the conductive agent, carbon powder, a metal material such as copper or aluminum, an organic conductive material such as a polyphenylene derivative, or the like can be used. The carbon powder is preferably carbon black such as superconducting carbon black, graphite, activated carbon, carbon nanotube, or carbon nanohorn powder.

The organic binder is a polymer dispersion, and specifically, a thermoplastic resin such as a fluorine-based resin such as polytetrafluoroethylene (PTFE, teflon (registered trademark)), or a polyolefin-based resin such as polypropylene (PP) is preferable.

The metal electrode 15 is supported by a pair of left and right support members 30 in the battery case 11, and faces the air electrodes 13A and 13B. The metal electrode 15 is formed of a metal plate made of a magnesium alloy, and is disposed parallel to the air electrodes 13A and 13B. The electrolyte of the metal-air battery 10 is an aqueous sodium chloride solution. That is, the metal-air battery 10 of the present embodiment is a magnesium-air battery. In the magnesium air battery, since seawater or a liquid obtained by mixing a salt with tap water can be used as the electrolyte, the electrolyte can be easily supplied. Further, a bag containing sodium chloride as an electrolyte may be disposed in advance inside the battery case 11, and power generation may be performed only by injecting water such as tap water. The mass of sodium chloride in the electrolyte is preferably 4% to 18% with respect to the mass of the solvent. If the amount is less than 4%, the electrolyte is insufficient, the liquid resistance is large, and the battery performance is not reliable, and if the amount exceeds 18%, the electrolyte gradually evaporates with discharge, and salt precipitates to become a resistance, and the battery performance is not reliable.

The metal electrode 15 has a pair of left and right anode pieces 15a1 extending upward and exposed above the electrolytic solution, and one of the anode pieces 15a1 is used as a wiring connection portion for connecting the power wiring 52 (fig. 3).

As shown in fig. 1, cut-out portions 15a2 cut upward are formed at the lower left and right ends of the metal electrode 15, and the outer shape of each cut-out portion 15a2 matches the outer shape of the anode sheet 15a 1. Thus, the upper surface and the lower surface of the metal electrode 15 are formed in the same shape, and when the metal electrode 15 is cut from one metal plate (a magnesium alloy plate in this configuration), the metal electrode can be continuously cut without a gap.

In this configuration, when the metal electrode 15 is inserted into the battery case 11 together with the pair of left and right support members 30, the metal electrode 15 is positioned in the battery case 11 by the support members 30. Thus, the metal electrode 15 faces the air electrodes 13A and 13B exposed to the inside through the opening 22K, and the inter-electrode distances LA and LB, which are the separation distances between the air electrodes 13A and 13B and the metal electrode 15, are kept constant. Alternatively, the metal electrode 15 may be inserted after the support member 30 is inserted into the battery case 11 in advance.

The pair of left and right support members 30 are formed of the same member, and more specifically, the support members 30 include: a support member body 31 detachably attached to the metal electrode 15 and extending in the vertical direction (Y direction); and a plurality of (4) abutting portions 41 that protrude from the support member body 31 and abut against the inner surface of the battery container 11. Each contact portion 41 includes: a pair of upper and lower front protruding portions 42 protruding forward (+ X direction) from the support member main body 31; and a pair of upper and lower rear protruding portions 43 protruding rearward (-X direction) from the support member body 31.

When the support member 30 is inserted into the battery case 11, the protruding surface of the front protruding portion 42 of the support member 30 abuts against the front wall portion 22, and the protruding surface of the rear protruding portion 43 abuts against the rear wall portion 23, whereby the front and rear positions of the metal electrode 15 supported by the support member 30 are positioned. The front protruding portion 42 also protrudes outward in the right and left directions and abuts against the side wall portion 24 of the battery case 11, thereby positioning the right and left positions of the metal electrode 15. This allows the metal electrode 15 to be positioned in the battery case 11, and the inter-electrode distances LA, LB, and the like to be kept constant.

The pair of left and right support members 30 support the metal electrode 15 so as to be spaced apart from the bottom plate portion 21 of the battery case 11.

When the amount of the metal electrode 15 serving as the negative electrode active material is sufficient, the battery capacity depends on the amount of water serving as a solvent of the electrolyte. Therefore, the inventors have made various studies to secure a capacity and obtain a high generated voltage in an air battery having the same battery capacity. In this configuration, as shown in fig. 2, the metal electrode 15 is disposed at a position close to either one of the air electrodes 13A and 13B on both sides, whereby a high generated voltage is obtained while ensuring a capacity. Hereinafter, examples and comparative examples will be described. In addition, the embodiments are not limited to the following embodiments.

Fig. 3 (a) shows example 1, fig. 3 (B) shows comparative example 1, and fig. 3 (C) shows comparative example 2. Fig. 3 (a) to 3 (C) show cross-sectional structures at the right and left centers of the metal-air battery 10 of example 1 and comparative examples 1 and 2. In each figure, reference numeral 51 denotes a power line connected to the air electrodes 13A and 13B, and reference numeral 52 denotes a power line connected to the metal electrode 15.