CN1130786C

CN1130786C - Forming method and forming equipment for air electrode of cylindrical zinc-air battery

Info

Publication number: CN1130786C
Application number: CN01107406A
Authority: CN
Inventors: 周震涛; 周晓斌
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2001-01-05
Filing date: 2001-01-05
Publication date: 2003-12-10
Anticipated expiration: 2021-01-05
Also published as: CN1301049A

Abstract

The invention relates to a method for forming an air electrode of a cylindrical zinc-air battery, which comprises the following steps: mixing materials, namely fully mixing the materials and fiberizing the materials; molding, namely molding the primary material package obtained by mixing; the forming equipment used by the forming method consists of a front roller, a rear roller, a transmission gear, a detachable shaft sleeve and a bracket base provided with a rotating bolt, wherein the front roller and the rear roller are fixed on the bracket base, one end of the front roller and the rear roller is provided with the transmission gear, and the other end of the front roller and the rear roller is provided with a detachable positioning shaft sleeve; the distance between the front roller and the rear roller is adjusted by a rotating bolt on the base of the bracket so as to control the thickness of the air electrode; the invention simplifies the production process and effectively improves the sealing performance of the zinc-air battery by a molding method of directly molding the zinc-air battery into a cylindrical air electrode at one time.

Description

Forming method and forming equipment for air electrode of cylindrical zinc-air battery

Technical Field

The invention relates to the technical field of directly converting chemical energy into electric energy, in particular to a forming method and forming equipment for an air electrode of a cylindrical zinc-air battery.

Background

The zinc-air battery is a battery which takes zinc as a negative active material and oxygen in the air as a positive active material, and generates electric energy by the electrochemical reaction of the two active materials under the catalytic action of a catalyst. After the oxygen is consumed, the battery continuously draws fresh oxygen from the air to continue to generate electricity. Therefore, the battery can be continuously operated as long as sufficient zinc and electrolyte exist as the anode material. It follows that zinc air cells are batteries for the negative electrode and essentially act as energy converters for the positive electrode. Therefore, it has the obvious characteristics of high specific energy which can theoretically reach 1350Wh.kg ^-1 . Taking a common alkaline zinc-air battery as an example, the reaction of two poles is as follows: negative electrode Positive electrode Cell reaction

The manufacture process of cylindrical zinc-air battery, including the mixing and forming of air electrode, is reported by Lutianhong et al in Power technology (1980, vol. 2, no. 5). The material mixing is to fully mix the materials by using a large-scale double-roller mixing roll and enable the materials to be fiberized; the molding is to repeatedly roll the mixture into a sheet-like object and then to connect the head and the tail into a cylindrical electrode. Thus, a connecting seam is formed in the cylindrical air electrode in an end-to-end connection mode, and the difficulty in sealing the air electrode is increased. The process is also complex, and the large-scale industrial production is difficult, so the zinc-air battery can not realize industrialization until now. Fig. 1 is a flow chart of a production process thereof. As shown in the figure, the air electrode is formed into a cylindrical electrode through mixing, coagulation, rolling, bonding and the like.

Disclosure of Invention

The invention aims to improve the defects of the prior art and design a forming method of the air electrode of the cylindrical zinc-air battery, which has simple operation and high efficiency and is easy for large-scale production, thereby greatly improving the production efficiency of the cylindrical zinc-air battery and improving the sealing performance of the zinc-air battery.

The invention also aims to provide equipment for forming the air electrode of the cylindrical zinc-air battery.

The forming method of the air electrode of the cylindrical zinc-air battery comprises the following steps:

mixing, i.e. fully mixing the materials and fiberizing the materials;

molding, namely molding the primary material package obtained by mixing; during molding, adding a primary material obtained by mixing materials between a front roller and a rear roller of a molding roller, wetting the front roller by alcohol in advance to enable the primary material to wrap the front roller in the molding process, and adjusting the distance between the front roller and the rear roller to control the thickness of a pole piece; after molding, the roller is removed, and the cylindrical catalytic membrane or the waterproof breathable membrane can be directly obtained; and finally, pressing the catalytic film, the waterproof breathable film and the foam nickel net on a front roller to form a cylindrical air electrode from inside to outside in sequence.

The forming method ensures that the air electrode does not need to be connected end to end, and no connecting seam exists, thereby simplifying the production process of the air electrode and improving the sealing performance of the air electrode to a great extent.

The forming equipment of the air electrode of the cylindrical zinc-air battery used by the method is characterized by comprising a front roller, a rear roller, a transmission gear, a detachable shaft sleeve and a bracket base provided with a rotating bolt, wherein the front roller and the rear roller are fixed on the bracket base, one end of the front roller and the rear roller are provided with the transmission gear, and the other end of the front roller and the rear roller are provided with a detachable positioning shaft sleeve; the distance between the front and rear rollers is adjusted by a rotary bolt on the base of the support so as to control the thickness of the air electrode.

The detachable design of the shaft sleeve is convenient for the cylindrical air electrode after the wrapping roller is pressed to be detached from the front roller.

Compared with the prior art, the invention has the following advantages: the forming method of the cylindrical air electrode by one-step direct forming simplifies the production process, improves the production efficiency, effectively improves the sealing performance of the zinc-air battery, and fundamentally solves the problems of liquid leakage and alkali leakage of the battery.

Drawings

FIG. 1 is a flow chart of a production process of a conventional cylindrical zinc-air battery;

FIG. 2 is a schematic flow chart of the manufacturing process of the air electrode of the zinc-air battery of the invention;

FIG. 3 is a schematic structural view of an air electrode forming apparatus of a cylindrical zinc-air battery according to the present invention;

the best mode of the present invention will be further described with reference to the following examples and the accompanying drawings.

Detailed Description

Fig. 2 is a schematic flow chart of the manufacturing process of the air electrode of the zinc-air battery. The cylindrical air electrode is prepared by the process steps of mixing, coagulating, front roller rolling, wrapping roller forming, wrapping roller pressing and the like. FIG. 2 is a diagram that the mixing and forming are divided into two sections, and each section is performed on different equipment, and finally, a cylindrical air electrode can be directly obtained; in the traditional process flow, the material mixing and the forming are carried out on the same equipment, so that only a sheet electrode can be obtained, and if a cylindrical electrode needs to be manufactured, the process steps of head-to-tail bonding are required to be added, so that the problem of leakage and sealing of the battery is caused.

As shown in fig. 3, the forming equipment of the air electrode of the cylindrical zinc-air battery mainly comprises a front roller 1, a rear roller 2, a transmission gear 3, a detachable shaft sleeve 4 and a bracket base 5 provided with a rotating bolt. The

rollers

1 and 2 are fixed on the bracket base 5, one end is provided with a transmission gear 3, and the other end is provided with a detachable positioning shaft sleeve 4; the distance between the two rollers is adjusted by means of rotating bolts on the support base 5 in order to control the thickness of the air electrode.

The process steps for producing the zinc-air cell with the apparatus of fig. 3 are as follows: -manufacturing of the air electrode:

the preparation method of the waterproof breathable film comprises the following steps: firstly, acetylene black and sodium sulfate in a certain proportion are uniformly mixed by alcohol, then polytetrafluoroethylene emulsion is slowly added, after coagulation, material mixing by a back roller is carried out to enable the mixture to be fiberized, and finally, the mixture is rolled into a cylinder on an upper covering roller. The weight ratio of the materials is as follows: acetylene black, sodium sulfate and polytetrafluoroethylene emulsion = 2: 1: 8; the process of the catalytic membrane is the same as above. The catalytic membrane mainly comprises catalytic materials, active carbon, sodium sulfate, polytetrafluoroethylene emulsion and the like. The weight ratio of the materials is as follows: catalytic material, activated carbon, sodium sulfate, polytetrafluoroethylene emulsion = 2: 1: 3. Finally, the catalytic film, the waterproof breathable film and the foamed nickel are sequentially rolled up from inside to outside to form the cylindrical air electrode. The solid content of the polytetrafluoroethylene emulsion used is generally 60%, and the operating temperature is room temperature. Preparation of zinc electrode, separator and battery case:

the zinc electrode adopts pasty zinc paste. The main components of the electrolyte are metal zinc powder, zinc oxide, corrosion inhibitor, thickener, potassium hydroxide electrolyte and the like. The diaphragm is polypropylene non-woven fabric. The battery shell is a stainless steel shell which is the same as the shell of a common zinc-manganese battery. The positive end of the anode needs to be additionally provided with a hole as an air inlet hole. -assembly of the sample cell:

after the cylindrical air electrode is formed, firstly sheathing the cylindrical air electrode into an upper top cover, carrying out thermal fusion through an external heating source, then placing the air electrode into a battery shell, lining a cylindrical diaphragm cylinder, filling zinc paste into the cylinder, then sheathing the cylindrical air electrode on the upper top cover and the lower top cover, carrying out thermal fusion, and finally sealing the battery shell to obtain the sample battery.

The external dimension of the assembled battery is as follows: diameter 14.0mm and height 49.5mm. The open-circuit voltage of the battery is about 1.4V, the discharge capacity is about 4200mAh, and the average working voltage is about 1.2V.

The storage experiment of the sample battery prepared by the invention shows that the battery has no alkali leakage during the storage process, and the monthly decay of the capacity of the battery stored at normal temperature is less than 0.5 percent. Meanwhile, the stored sample battery is dissected after being discharged, and the phenomenon of alkali leakage does not occur at the joint of the cylindrical air electrode and the sealing buckle.

Claims

1. A method for forming an air electrode of a cylindrical zinc-air battery is characterized by comprising the following steps:

mixing, i.e. fully mixing the materials and fiberizing the materials;

molding, namely molding the primary material package obtained by mixing the materials; during molding, adding a primary material obtained by mixing materials between a front roller and a rear roller of a molding roller, wetting the front roller by alcohol in advance to enable the primary material to wrap the front roller in the molding process, and adjusting the distance between the front roller and the rear roller to control the thickness of a pole piece; after molding, the roller is taken off to directly obtain a cylindrical catalytic membrane or a waterproof breathable membrane; and finally, pressing the catalytic film, the waterproof breathable film and the foam nickel net on a front roller to form a cylindrical air electrode from inside to outside in sequence.

2. The forming equipment of the air electrode of the cylindrical zinc-air battery used in the method of claim 1 is characterized by comprising a front roller, a rear roller, a transmission gear, a detachable shaft sleeve and a bracket base provided with a rotating bolt, wherein the front roller and the rear roller are fixed on the bracket base, one end of the front roller and the rear roller is provided with the transmission gear, and the other end of the front roller and the rear roller is provided with a detachable positioning shaft sleeve; the distance between the front and rear rollers is adjusted by a rotary bolt on the base of the bracket so as to control the thickness of the air electrode.