JPS63904B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an air battery having an air electrode using oxygen in the air as an active material, and in which an electrolytic solution of a sulfamate aqueous solution and a positive or negative electrode can made of titanium or a metal whose inner surface is covered with conductive carbon are used. By using this, it is possible to provide a small air battery with high voltage, high capacity, and excellent storage performance. Conventional air batteries use oxygen as the positive electrode active material and zinc as the negative electrode active material, and the electrolyte is a 30-40% caustic alkali aqueous solution such as caustic soda or caustic potash saturated with zinc oxide. Add viscosity with a glue such as sodium acrylate to thickly cover the surface of the air electrode to prevent the oxygen reduction ability from decreasing, and prevent it from leaking from the air supply hole of the cathode can, which is made of nickel-plated steel. The batteries were miniaturized and sealed. Conventional air batteries used an alkaline electrolyte such as caustic potash, so when a large amount of carbon dioxide gas flows in in addition to oxygen from the air supply hole, potassium carbonate is produced, the alkaline concentration of the electrolyte decreases, and the electrical conductivity decreases. The battery discharge operating voltage decreases. Furthermore, the alkaline electrolyte dissolves zincate ions close to saturation.
When a large amount of carbon dioxide gas flows in, zinc carbonate is generated and deposited on the zinc surface. As a result, the discharge reaction area is reduced, resulting in a decrease in discharge operating voltage and discharge capacity. As an improvement to this, an air battery using a sulfamate aqueous solution was developed, but during long-term storage, the acidic electrolyte corroded the positive electrode can made of nickel-plated steel, producing corrosive gas and causing the positive electrode can to swell. It has disadvantages such as damaging the air electrode, reducing the oxygen reduction ability of the air electrode, and greatly deteriorating the discharge performance and storage performance. The present invention uses an acidic electrolyte consisting of an aqueous sulfamate solution and a positive or negative electrode can made of titanium or metal whose inner surface is covered with a conductive carbon layer. It provides air batteries. Embodiments of the present invention will be described based on the drawings. Reference numeral 1 denotes a positive electrode case made of titanium or metal whose inner surface is covered with a conductive carbon layer, which also serves as a positive electrode terminal, and has an air supply hole 2 at the bottom. 3 is an air electrode consisting of a cobalt phthalocyanine catalyst and activated carbon;
It is in contact with isolation paper 4, which is a lyophilic semipermeable membrane. 5
is an electrolyte holding material that holds an acidic electrolyte of sulfamate, and is a nonwoven fabric or porous material with excellent liquid retention and acid resistance, and is in contact with the negative electrode body 6 made of zinc powder. Reference numeral 7 is paper with excellent air permeability, which is in contact with the air electrode 3 through a Teflon air-permeable membrane 8 having many micropores, and the other side is the bottom of the positive electrode can 1 where the air supply holes 2 are provided. is in contact with Reference numeral 9 denotes a negative electrode can made of titanium or a metal whose inner surface is covered with a conductive carbon layer, and the opening of the positive electrode can 1 is bent through a gasket 10 to seal the battery. 11
is a polyvinyl chloride sheet sealant that seals the air supply hole 2, and the positive electrode can 1 is sealed with a pressure-sensitive adhesive 12.
The air supply hole 2 at the bottom of the is sealed. Since the battery of the present invention uses an acidic electrolyte of sulfamate, there is no generation of carbonate due to carbon dioxide gas flowing in from the air supply hole 2 of the positive electrode can 1.
There is no deterioration of the electrolytic solution, there is no drop in the battery discharge operating voltage, and since there is no precipitate, there is no decrease in discharge capacity, and a high-voltage, large-capacity air battery can be obtained. Further, since the present invention uses the positive electrode can 1 or the negative electrode can 9 made of titanium or a metal whose inner surface is covered with a conductive carbon layer, it has excellent corrosion resistance and will not be corroded by acidic electrolyte during long-term storage. There is no deterioration of the oxygen reduction ability caused by the generation of corrosive gas and adhesion to the air electrode 3, no damage to the battery, and the discharge performance and storage performance are greatly improved. Furthermore, in the air battery of the present invention, when a sulfamate aqueous solution with a pH of 1 is used, the discharge operating voltage is approximately 1.5V, which is 0.2V compared to the operating voltage of 1.3V when an alkaline electrolyte with a pH of 15 is used. The increase in voltage results in high capacity and high voltage. Next, a metal positive electrode can 1 whose inner surface is covered with a conductive carbon layer, which is an example battery according to the present invention, and a PH
The invention product [A] is a small air cell with a diameter of 11.5 mm and a height of 5.2 mm using an acidic electrolyte of a sulfamate aqueous solution of = 1, and a positive electrode made of steel with nickel plating on the entire surface. 10 each of the conventional product [B], which uses cans and is the same type of air battery except for the same type,
Discharge at 25℃ with a constant current of 1.5mA, and change the discharge curve to the second
The discharge capacity is shown in Table 1, and the invention product [A] 20
20 pieces of conventional product [B] were stored at 25°C, and in the 6th and 12th month, 10 pieces each were discharged at 25°C with a constant current of 1.5 mA, and the results are summarized in Table 1.

[Table] From FIG. 2 and Table 1, it can be seen that the product [A] of the present invention has a high discharge operating voltage, a long duration, and excellent storage performance. In addition, since the air battery of the present invention has an operating voltage of 1.5V, it can be used as an alkaline manganese battery, a silver oxide battery, or
It is compatible with nickel zinc batteries, etc. As described above, an air electrode, an acidic electrolyte consisting of an aqueous sulfamate solution, and a negative electrode body are inserted into a positive or negative electrode case made of titanium or a metal whose inner surface is covered with a conductive carbon layer, and sealed with a gasket. The small air battery of the present invention has a high discharge operating voltage and an improved discharge capacity, and has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a small air battery according to an embodiment of the present invention, and Fig. 2 is a cross-sectional view of a small air battery according to an embodiment of the present invention.
FIG. 2 is a comparison diagram of discharge curves at a constant current of 1.5 mA at °C. 1... Positive electrode can, 2... Air supply hole, 3... Air electrode, 5... Electrolyte holding material, 9... Negative electrode can.

Claims (1)

[Claims] 1. A small air battery using an air electrode, an acidic electrolyte consisting of an aqueous sulfamate solution, and a positive or negative electrode can made of titanium or a metal whose inner surface is covered with a conductive carbon layer.