JP2877809B2 - Manufacturing method of button type air battery - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a button-type air battery, and more particularly, to a method for manufacturing a button-type air battery, which is excellent in liquid leakage resistance and free from poor conduction between a positive electrode catalyst layer and a positive electrode can. The present invention relates to a method for easily manufacturing a button-type air battery. [Technical background of the invention and its problems] Various types of air cells using oxygen in the air as an anode active material are known, and among them, a button type air cell is It is common to manufacture in this way. That is, as shown in FIG. 3, the air diffusion paper 3 is placed in the concave portion 1a of the positive electrode can 1 having the concave portion 1a in which the air supply hole 2 is formed on the bottom surface and the opening on the upper portion. Thereafter, a water repellent film 4 having a diameter substantially equal to or slightly larger than the inner diameter of the positive electrode can 1 and a positive electrode catalyst layer 5 having a separator 6 adhered to the upper surface are sequentially laminated. Next, after fitting the negative electrode lid 8 filled with the negative electrode active material 9 to the opening of the positive electrode can 1 via the insulating gasket 7, the peripheral edge of the opening of the positive electrode can 1 is bent inward and caulked. The entire battery was sealed. Further, as another method, JP-A-59-194361 discloses that a positive electrode catalyst layer is incorporated into a positive electrode can and the peripheral portion of the positive electrode catalyst layer is pressurized at the time of caulking at the time of sealing or before being incorporated into the positive electrode can. It is disclosed that the porosity of the catalyst layer is made smaller than that of the central part. However, the button-type air battery manufactured by applying the above method has a problem that leakage of electrolyte and poor conduction frequently occur. First, as a cause of the electrolyte leakage, in the step of fitting the negative electrode lid 8 and caulking the positive electrode can 1, the periphery of the water-repellent film 4 is not in close contact with the inner wall of the positive electrode can 1. Separator 6 at pressure when caulking 1
It is considered that the electrolytic solution impregnated into the water-repellent film 4 reaches the lower side of the water-repellent film 4 through the minute gap between the inner wall of the positive electrode can and the water-repellent film 4. On the other hand, in the button-type air battery described above, the cause of the poor conduction is presumed as follows. That is, the positive electrode catalyst layer 5 is generally formed by pressing a sheet-shaped catalyst layer to a Ni net as a current collector. Then, in the conventional manufacturing process, in the final process of caulking the positive electrode can, the peripheral portion of the Ni net of the catalyst layer is spread radially outward by pressure downward of the gasket 7 to form a positive electrode. The contact between the catalyst layer 5 and the positive electrode can 1 is achieved by contact with the inner wall of the can. However, gasket 7
Is usually made of a relatively flexible material such as plastic, so that it absorbs a considerable amount of pressure applied at the time of caulking, and extends the peripheral portion of the Ni net of the cathode catalyst layer 5 as described above. Even if the peripheral portion is pressurized in advance, the contact between the positive electrode can and the Ni net of the positive electrode catalyst layer is lost, and as a result, poor conduction between the positive electrode catalyst layer 5 and the positive electrode can 1 frequently occurs. Furthermore, in the conventional manufacturing method, since the water-repellent film 4 and the positive electrode catalyst layer 5 are simply placed on the bottom of the positive electrode can 1, when the negative electrode lid 8 is fitted, the positive electrode can 1 is turned upside down. The negative electrode cover 8 filled with the negative electrode active material 9
Upside down and fitted into the opening of the positive electrode can 1. Therefore, when the negative electrode cover 8 is fitted, the negative electrode active material 9 may fall or a part of the negative electrode active material 9 may be scattered and adhere to the inner wall of the anode can 1, thereby causing a reduction in manufacturing yield. was there. The present invention solves the above-described conventional problems, and provides a button-type air battery that is excellent in liquid leakage resistance and does not cause poor conduction between the positive electrode catalyst layer and the positive electrode can, such as dropping and scattering of the negative electrode active material. It is an object of the present invention to provide a method which can be easily manufactured with a good yield without causing a problem. [Summary of the Invention] The present inventors have found that in a button-type air battery obtained by applying a conventional manufacturing method, the cause of liquid leakage and poor conduction is caused by the gap between the inner wall of the positive electrode and the water repellent film. , And as a result of intensive research on the fact that it is due to poor adhesion between the inner wall of the positive electrode can and the positive electrode catalyst layer, as described later, in the assembly process of the button type air battery, ,
It has been confirmed that the above object can be achieved by adding a step of pressing the water repellent film and the positive electrode catalyst layer to the inner wall of the positive electrode can by pressing, thereby completing the present invention. That is, the method for manufacturing a button-type air battery of the present invention includes:
After placing the air diffusion paper on the bottom of the positive electrode can, on the diffusion paper,
In a method for manufacturing a button-type air battery comprising a step of stacking and housing a water-repellent film and a positive electrode catalyst layer in this order, the diameter of both the water-repellent film and the positive electrode catalyst layer is made slightly smaller than the inner diameter of the positive electrode can. And pressurizing the vicinity of the periphery of the upper surface of the positive electrode catalyst layer with a pressure of 50 to 500 kg / cm ² . Further, in the above manufacturing process, before the air diffusion paper is placed on the bottom of the positive electrode can, the method includes a step of applying an adhesive to the periphery of the bottom of the positive electrode can, so that the electrolyte wraps around the water-repellent film. This is more effective in preventing the battery from leaking. Hereinafter, the manufacturing process of the button-type air battery to which the method of the present invention is applied will be described step by step. First, air diffusion paper is stored in the bottom of the positive electrode can, and then a water-repellent film and a positive electrode catalyst layer are sequentially laminated. In the method of the present invention, the diameter of both the water repellent film and the positive electrode catalyst layer needs to be slightly smaller than the inner diameter of the positive electrode can. This is due to the consideration of the diameter expansion of both in the subsequent pressing step. Specifically, it is preferable that both have a diameter smaller by about 0.05 to 1 mm than the inner diameter of the positive electrode can. In this state, the air diffusion paper, the water-repellent film, and the positive electrode catalyst layer are simply placed and stacked in the positive electrode can, and thus fall if the positive electrode can is turned upside down. Thereafter, the vicinity of the periphery of the upper surface of the positive electrode catalyst layer is pressurized downward. This pressurizing step may be performed immediately after the positive electrode catalyst layer is laminated, or may be performed after the separator is laminated on the positive electrode catalyst layer. Further, any means can be applied to the pressurizing step,
For example, using a pressure rod as shown in FIG. 1 is simple and reliable. That is, in FIG.
The same components are denoted by the same reference numerals.
The step portion 1b of the concave portion 1a of the positive electrode can 1 of the button type air battery in which the separator 6 is stacked and accommodated by 11 is fixedly supported, and thereafter has a diameter smaller than the inner diameter of the positive electrode can by about 0.1 to 1 mm. A pressing force is applied downward from above the separator 6 using the push rod 12 of FIG. At this time, the pressing force is mainly applied to the step portion 1b of the laminate, and its magnitude is preferably set to 50 to 500 kg / cm ² . If the pressure is less than 50 kg / cm ² , it is difficult to sufficiently adhere the cathode can to the cathode catalyst layer to achieve a good conduction state, while if it exceeds 500 kg / cm ² , the cathode catalyst layer may be deformed. It is not preferable. In this pressurizing step, the water-repellent film 4 and the positive electrode catalyst layer 5 are both enlarged in diameter as described above, and the peripheral portion thereof is
The liquid leakage and conduction failure are securely prevented by closely contacting the inner wall of the battery. Further, even if the cathode can 1 is turned upside down in this state, the diffusion paper 3, the water-repellent film 4, the cathode catalyst layer 5, and the separator 6
Does not fall. After the above process, the negative electrode cover filled with the negative electrode active material is fitted to the opening of the positive electrode can via a gasket, and the positive electrode can is caulked and sealed to complete a button-type air battery. In the method of the present invention, as described above,
Since the positive electrode can 1 can be turned upside down, instead of turning the negative electrode cover filled with the negative electrode active material upside down as in the conventional case, the negative electrode lid filled with a gasket and further filled with the negative electrode active material is put on the negative electrode lid. It is possible to adopt a process in which the two can be fitted by turning the can 1 upside down. For this reason, the problem of the falling or scattering of the negative electrode active material as in the related art is solved. In the method of the present invention, a step of applying an adhesive to the periphery of the bottom surface of the positive electrode can may be added before the step of storing the diffusion paper in the positive electrode can in the above-described manufacturing process. The application of the adhesive makes it possible to reliably prevent liquid leakage due to the electrolyte flowing under the water-repellent film. Specifically, for example, as shown in FIG. 2, first, an adhesive is applied in a ring shape to the bottom peripheral region of the positive electrode can 1. At this time, the range in which the adhesive 13 is applied is preferably a region extending from the entire surface of the step portion 1b of the concave portion 1a at the bottom of the positive electrode can 1 to the peripheral edge of the bottom surface of the concave portion 1a, as shown in the figure. Incidentally, the adhesive used is preferably one that remains tacky even after being dried, for example,
Rubber-based and synthetic resin-based adhesives are preferred. After the adhesive 13 is applied in this manner, the air diffusion paper 3 is placed in the recess 1a.
Is placed, first, the periphery of the diffusion paper 3 is fixed to the bottom surface of the concave portion 1a by the adhesive 13. Next, the water-repellent film 4 is laminated on the diffusion paper 3, and the peripheral portion of the water-repellent film 4 is fixed to the positive electrode can 1 with the adhesive of the step portion 1b. And then,
The steps of laminating the cathode catalyst layer 5 and the separator 6, the step of pressing these laminates, and the step of assembling the anode lid may be performed by applying the same steps as those described above. Example As an example, a case where the method of the present invention is applied to the manufacture of a 44 type zinc-air battery will be described. After the air diffusion paper was stored at the bottom of the positive electrode can, a porous PTFE membrane having a diameter smaller than the inner diameter of the positive electrode can by 0.5 mm was laminated on the diffusion paper as a water-repellent film. Next, a positive electrode catalyst layer and a separator were laminated on the porous PTFE membrane. The positive electrode catalyst layer and the separator were manufactured as follows. That is, first, 70% by weight of activated carbon and 30% by weight of PTFE powder were mixed, and a catalyst sheet having a thickness of about 0.5 mm was formed by a roller or the like. Then, the catalyst sheet and a wire diameter of 0.1 mm, 6
A 0 mesh Ni net current collector was pressed using a roller. A PTFE porous membrane having a thickness of 0.1 mm is brought into contact with the catalyst layer surface of this laminate, and a polypropylene non-woven fabric is adhered to the Ni net surface as a separator using CMC or the like,
This was used as a positive electrode catalyst layer. In this example, this positive electrode catalyst layer was punched and used so as to have a diameter smaller than the inner diameter of the positive electrode can by 0.5 mm. Thereafter, the laminate in the positive electrode can was pressed downward by using a support base as shown in FIG. 1 and a polypropylene push rod having a diameter smaller than the inner diameter of the positive electrode can by 0.5 mm. The pressing force at this time was 70 kg / cm ² . After the completion of this step, even when the positive electrode can was turned upside down, the laminated body in the positive electrode can, that is, the diffusion paper, the water-repellent film, and the positive electrode catalyst layer did not fall. Then, after filling the negative electrode lid with the gasket fitted therein with the negative electrode zinc and the electrolytic solution, the above positive electrode can was covered and fitted. Finally, the periphery of the positive electrode can was swaged to seal the entire battery, thereby completing a button-type air battery. With respect to the 500 type 44 zinc-air batteries manufactured in this manner, the presence or absence of poor conduction, the discharge capacity at 250Ω, and the storage leakage rate for one month were examined, and the results are shown in the table. The storage leakage rate is a value obtained by measuring the number of batteries in which the alkaline electrolyte has leaked to the outside after being stored in a constant temperature and humidity layer at a temperature of 45 ° C. and a relative humidity of 90% for one month. In addition, the conduction failure is obtained by measuring the number of the positive electrode catalyst layers dropped from the positive electrode can when the positive electrode can was turned upside down after the positive electrode catalyst layer was pressurized with a push rod in the positive electrode can. For comparison, the same evaluation test was performed on 500 type 44 zinc-air batteries manufactured by applying the conventional method, and the results are also shown in the table. [Effects of the Invention] As is clear from the above description, the button-type air battery manufactured by applying the method of the present invention has, in particular, poor conduction and leakage, as compared with those obtained by applying the conventional method. The liquid ratio was drastically reduced, and it was confirmed that the composition had good characteristics. Furthermore, in the method of the present invention, in the step of assembling the negative electrode lid, it is not necessary to turn the negative electrode lid filled with the negative electrode active material upside down, so that the negative electrode active material frequently generated in the conventional method does not fall or scatter. This is extremely advantageous in terms of the process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are longitudinal sectional views of a button type air battery showing the structure of the method of the present invention, and FIG. 3 is a longitudinal sectional view showing the structure of a conventional button type air battery. . DESCRIPTION OF SYMBOLS 1 ... Positive electrode can, 1a ... Concave part, 1b ... Step part, 3 ... Air diffusion paper, 4 ... Water repellent film, 5 ... Positive catalyst layer, 6 ... Separator, 8 ... Negative electrode lid, 9 … Negative electrode active material, 11… support base, 12… push rod, 13… adhesive.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitomi Sato 3-4-1-10 Minamishinagawa, Shinagawa-ku, Tokyo Toshiba Battery Co., Ltd. (72) Inventor Toshiaki Nakamura 1 Kosuka Toshiba-cho, Koyuki-ku, Kawasaki Stock (56) References JP-A-59-143282 (JP, A) JP-A-58-169780 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01M 12 / 06

Claims (1)

(57) [Claims] After the air diffusion paper is placed on the bottom of the positive electrode can, a water-repellent film and a positive electrode catalyst layer are stacked and stored in this order on the diffusion paper. Both the diameter of the positive electrode catalyst layer is 0.05 to 1 mm smaller than the inner diameter of the positive electrode can, and including a step of pressing the periphery of the upper surface of the positive electrode catalyst layer at a pressure of 50 to 500 kg / cm ^2. A method for manufacturing a button-type air battery. 2. 2. The method according to claim 1, further comprising a step of applying an adhesive to the periphery of the bottom of the positive electrode can prior to placing the air diffusion paper on the bottom of the positive electrode can.