JP2014063643A - Method for housing positive electrode mixture in metal-air battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for housing a positive electrode mixture in a metal-air battery capable of being easily assembled, easily increasing and decreasing the amount of the positive electrode mixture and being also used as a fuel battery by replacing a negative electrode metal.SOLUTION: As in Fig. 1, a metal-air battery 1 is formed by laminating a negative electrode metal 2, a separator 3 used for water absorption and moisture retention, a positive electrode mixture 4, an air-permeable and water-repellent foam frame 5 and a collector 6 as a collector. The foam frame 5 prevents the positive electrode mixture 4 and an electrolyte from leaking out and effectively takes in oxygen as a positive electrode active material with its water-repellency. The foam frame 5 changes its thickness to increase or decrease the amount of the positive electrode mixture 4 to a necessary amount. An adhesive is added to one surface or both surfaces of the foam frame to fix the foam frame to the separator 3 and the collector 6. Consequently, the battery can be easily assembled. The negative electrode metal 2 that dissolves with chemical reaction in the battery and the separator 3 can be replaced so that the battery can be also used as a fuel battery capable of repeated power generation.

Description

The present invention is a technique for storing a positive electrode mixture in a metal-air battery that can be easily assembled and used as a fuel cell.

Conventionally, a metal-air battery using magnesium, an alloy thereof, or another metal as a negative electrode is known. In particular, in the case of a battery using magnesium, aluminum or an alloy thereof as a negative electrode, it is used in such a way that an electrolyte is poured during use due to problems such as self-discharge and difficulty in reducing and charging reaction products. (For example, Patent Documents 1 and 2). In the case of a battery of such a form, the positive electrode mixture is activated carbon, carbon, other reaction catalyst and a resin molded into a paste, or a reaction fiber or foam such as a conductive sponge. Such a structure is often used that is held by a binder such as a resin.

JP 2010-62074 A JP2012-134160

However, in the positive electrode structure as described above, leakage of the electrolyte solution or positive electrode mixture of the positive electrode is likely to occur, and conductivity is likely to decrease due to a binder for holding the reaction catalyst or the like. Further, in order to prevent leakage of electrolyte etc., the positive electrode in the conventional metal-air battery has been devised to be housed in a case or to form a water repellent film with a fluorine resin such as PTFE. . The increase or decrease in battery capacity has also been affected by the amount of positive electrode mixture. For this reason, it is difficult to cope with changes in capacity, and this has been accompanied by problems such as an increase in manufacturing cost and a complicated manufacturing process and structure, resulting in a decrease in production efficiency and a difficulty in forming a cell stack.

The present invention has been made to solve the problems of the prior art in the structure of a metal-air battery, is easy to assemble, and can be used as a fuel cell. Technology.

The present invention comprises a metal that serves as a negative electrode, a separator that also serves to absorb water and moisture, a positive electrode mixture, a foam material frame that is formed so as to surround it, and a metal plate that serves as a current collector. The body is breathable and water-repellent, prevents leakage of the cathode mixture and electrolyte, and efficiently generates power by incorporating oxygen as the cathode active material. This is a technique for storing the agent.

This is a technique for storing a positive electrode mixture in a metal-air battery that can easily increase or decrease the battery capacity because the amount of the positive electrode mixture entering the inside can be increased or decreased by changing the thickness of the foam.

The metal-air battery according to claim 1, wherein the metal-air battery can be used as a fuel cell capable of repeated power generation by replacing the negative electrode metal and the separator. Method technology.

Further, the present invention provides the metal-air battery according to claim 1, wherein the positive electrode mixture holds an electrolyte, a reaction catalyst, and the like in advance, and can generate electric power by pouring water or salt water. This is a technique of a positive electrode mixture storage method in an air battery.

The present invention, in the structure of the metal-air battery, by changing the thickness of forming a foam having air permeability and water repellency around the positive electrode mixture, while preventing leakage of the electrolyte and the positive electrode mixture, Air can be efficiently supplied to the positive electrode. Moreover, since the assembly is also easy, it can be used as a fuel cell capable of repeated power generation by replacing the negative electrode metal and the separator.

It is an exploded view showing the basic structure in the Example of this invention. It is sectional drawing which shows the basic structure of the positive mix, the foam material frame, and the electrical power collector in the Example of this invention. It is a figure of how to put in a conductive material frame in the example of the present invention. It is sectional drawing showing the difference in the thickness of a foam material frame in the Example of this invention. It is a figure showing the discharge characteristic in Example 1 of this invention. It is a figure showing the discharge characteristic in Example 2 of this invention.

The most preferred embodiment of the present invention will be described in more detail with reference to FIG. FIG. 1 is an exploded view of a metal-air battery according to the present invention. FIG. 2 shows an assembled state in which members 2 to 6 are in contact with each other.

In FIG. 1, 2 is a negative electrode metal, and as this metal, magnesium, aluminum or an alloy thereof can be used, and for example, iron, zinc, lithium, calcium, manganese, cobalt, lead, chromium, etc. A simple substance, an alloy, a composite, or the like can be used. Further, the negative electrode metal 2 may be processed such as a solidified metal powder or a mesh.

Reference numeral 3 denotes a separator that serves both as water absorption and moisture retention. For example, paper such as a coffee filter or filter paper, cloth, nonwoven fabric, water-absorbing resin, and the like can be used. Further, the present invention is not limited to these, and any material can be applied as long as it is made of a material that sucks up and holds the electrolytic solution.

4 is a positive electrode mixture, for example, a paste of activated carbon or carbon powder and catalyst, or a non-woven fabric in which the activated carbon or carbon powder and catalyst are held by a binder such as a resin. Any form may be used as long as it is formed as an air electrode. In addition, since the foam material frame is formed around, it is possible to enclose the positive electrode mixture in powder form.

In addition, it is more preferable that an electrolyte is mixed in the positive electrode mixture 4 in advance. It is also possible to generate electricity by directly injecting electrolyte into the separator of 3, but it is also possible to generate electricity by injecting water or salt water instead of injecting electrolyte due to the presence of electrolyte It becomes. Examples of the electrolyte include sodium hydroxide, potassium chloride, sodium chloride, copper sulfate, sodium nitrate, and the like. Any substance can be used as long as it is ionized into water and becomes an electrolyte.

Reference numeral 5 denotes a foam material frame, which may be of any form as long as it has air permeability such as foamed plastic, foamed sponge, conductive sponge, foamed metal, etc., but becomes an active material. A water-repellent material is more preferable in order to efficiently take in oxygen and prevent leakage of the electrolyte. FIG. 3 is a view of how to put the positive electrode mixture 4 into the foam material frame 5. 4 is a thin foam frame 5 as indicated by 7 in FIG. The amount of the positive electrode mixture 4 can be increased / decreased with a thick foam material frame 5 as indicated by 8 in FIG. 4B, whereby the lighting time of the battery can be adjusted.

6 is a current collector, and any material can be used as long as it is conductive, but a copper plate with high conductivity is more suitable.

Examples of the present invention will be described below.

Example 1
A magnesium plate (50 × 50 × 1 [mm]) as the negative electrode metal, a commercially available coffee filter as the separator, a commercially available malt plain as the foam material frame, and a SUS plate (50 × 50 × 1 [mm]) as the current collector are used. As a positive electrode mixture, 100 parts by weight of graphite, 20 parts by weight of ethylene black, 200 parts by weight of manganese dioxide, and 300 parts by weight of salt are pulverized in a mortar, and are encapsulated between the separator and the current collector as powder. Was made.

(Example 2)
The battery was produced in the same manner as in Example 1, and a cell stack was produced by stacking three batteries in series.

The discharge characteristics of the metal-air battery produced according to this example when water or salt water is injected are shown below. Moreover, the battery produced by the present Example did not show leakage of the positive electrode mixture and the electrolyte regardless of before and after water injection.

(Measuring method)
The output current was fixed at 100 mA with an electronic load, and the discharge voltage was measured.

From this, it was shown that the metal-air battery produced by this example functions well as an air battery without leakage of electrolyte solution and positive electrode mixture due to the foam material frame. The cell stack can also be manufactured by simply stacking and stacking, and the structure and assembly method of the battery itself are simple, so the separator and the negative electrode metal can be easily replaced. It was confirmed that it was possible.

It can be used for metal-air batteries, particularly flat plate structures.

DESCRIPTION OF SYMBOLS 1 Metal-air battery 2 Negative electrode metal 3 Separator 4 Positive electrode mixture 5 Foam material frame 6 Current collector 7 Foam frame thickness 8 Foam frame thickness

Claims (3)

A metal that serves as a negative electrode, a separator that also serves to absorb water and moisture, a positive electrode mixture, a foam material frame that is formed so as to surround the metal, and a metal plate that serves as a current collector. In a metal-air battery, which has the property of generating electricity and water repellency, prevents leakage of the positive electrode mixture and electrolyte, and at the same time, efficiently captures oxygen as the positive electrode active material through the foam frame. This is a technique for storing the positive electrode mixture. 2. The metal-air battery according to claim 1, wherein the metal-air battery can be used as a fuel cell capable of repeated power generation by replacing the negative electrode metal and the separator. 2. The metal-air battery according to claim 1, wherein the positive electrode mixture retains an electrolyte, a reaction catalyst, and the like in advance, and can generate electric power by pouring water or salt water. This is a technique for storing the agent.