JPS61140054A - Manufacture of thin cell - Google Patents

Abstract

PURPOSE:To adhere reliably by adhering the mounting film and a frame member under normal pressure then choking the through-hole in the sideface of said frame member under reduced pressure thereby preventing adhesion of electrolyte to the contacting face between said film and the frame member. CONSTITUTION:A through-hole 8a of small diameter is made through the sideface of polyethylene frame member 8 adhered through thermal fusion to the circumferential section of mounted films 6, 7. Such frame member 8 is assembled with generating elements such as positive pole black mix 2, negative pole 3, etc. wrapped from up and down by said films 6, 7 then thermally fused to the circumferential section of said films 6, 7 under normal pressure through well known method. The thin cell B manufactured in such a manner is heated at the outside section of through-hole 8a by means of fused zig 11 heated to 180 deg.C in pressure reduced chamber 9. Consequently, the outside section is fused to choke the through-hole 8a upon cooling.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for manufacturing a thin battery. Specifically, a power generating element is covered with two upper and lower outer films, and the peripheral edge of the outer film is shaped like a frame. The present invention relates to a method for manufacturing a thin battery that is bonded to each other via a frame, which prevents a decrease in leakage resistance due to poor adhesion between an exterior film and a frame-like frame.

<Prior art> As a manufacturing method for thin batteries such as thin alkaline batteries, neutral salt batteries, lithium batteries, etc., a positive electrode mixture and a negative electrode are laminated with a separator interposed between the positive electrode mixture and the negative electrode. A current collector plate is brought into contact with each of the other surfaces, and after the power generation element made as described above is covered with two upper and lower outer films, the peripheral edge of the outer film is wrapped around a frame-like frame. A method is known in which the current collector plates are bonded to each other and sealed, and a part of the current collector plate is exposed through a window hole provided in the center of the outer film to be used as a positive terminal or a negative terminal.

By the way, in such a manufacturing method, when bonding the exterior film and the frame-like frame in the final process of the battery, by using a method of heat-sealing them under reduced pressure, the current collector plate and the positive electrode mixture are bonded together. Alternatively, attempts have been made to improve the adhesion with the negative electrode.

<Problem that the invention seeks to solve> However, the above method has the following problems.

In other words, when the battery atmosphere is reduced in pressure prior to thermal fusion of the exterior film and the picture frame, the electrolyte contained in the positive electrode mixture, negative electrode, separator, etc. is degassed during the reduced pressure. As a result, it breaks off and adheres to the adhesive surface between the exterior film and the picture frame. The electrolytic solution present on the adhesive surface causes poor thermal adhesion between the exterior film and the picture frame, impairing the sealing properties of the battery, and resulting in an extremely low leakage resistance of the battery. . In addition, since the time-consuming work of heat-sealing the exterior film and the picture frame is carried out under reduced pressure, the work is complicated and there is a problem that the workability is reduced by 1&<.

<Means for Solving the Problems> In the method for manufacturing a thin battery of the present invention, a power generation element is covered with two upper and lower outer films, and the peripheral edges of the outer films are connected to each other through a frame-like frame. In the manufacturing method of a thin battery made by bonding, a through hole is provided in the side surface of a frame-like frame, and after the exterior film and the frame-like frame are adhered under normal pressure, the through hole is closed under reduced pressure. This is the summary.

Function> As described above, the exterior film and the frame-like frame are bonded under normal pressure, and then the battery is sealed by using a means to close the through hole provided on the side of the frame-like frame under reduced pressure. It is possible to prevent the electrolyte from adhering to the adhesive surface between the exterior film and the frame without impairing the adhesion between the current collector plate and the positive electrode mixture or the negative electrode when completed.

<Example> In FIG. 1 showing a thin alkaline battery, 1 is a separator made of a nonwoven fabric made of an alkali-resistant material such as polypropylene; 2 is a positive electrode mixture made of manganese dioxide and graphite:
3 is zinc powder and boria'y')'4i')-f? ″l*
M(''''') '7 A: 8i ')';; 4 is a positive electrode current collector plate made of nickel-plated iron foil that is in contact with the positive electrode mixture 2; 5 is a positive electrode current collector plate Negative electrode plate made of copper foil that contacts the negative electrode 3; 6 and 7 are exterior films made of a laminate film mainly made of plastic that is integrated with the current collector plates 4 and 5 using an epoxy resin adhesive; 8 is an exterior film This is a frame-like frame made of polyethylene that is adhered to the peripheral edge of 6.7 by heat fusion. Note that 4a and 5a are a positive terminal and a negative terminal. A 35% potassium hydroxide solution is used as the electrolytic solution, and the positive electrode mixture 2 and the separator 1 are injected and impregnated with the solution.

The frame-like frame 8 has the shape shown in FIGS. 2A and 2B, and has a small-diameter through hole 8a formed in its side surface. still,
t1 to t4 are 24 mm and 42 mm, respectively.2.
5mm and 0.5mm. Such a frame-like frame 8 is combined with a power generation element consisting of a positive electrode mixture 2, a negative electrode mixture 3, etc., which are covered from above and below by an exterior film 6.7, and then is combined with the peripheral edge of the exterior film 6.7. Heat fusion is performed by a known method at normal pressure (atmospheric pressure). The thin battery B made in this manner is fixedly supported by a fixture 10 in the decompression chamber 9 as shown in FIG. After the air in the decompression chamber 9 is sucked in the S direction and the thin battery B is placed in a depressurized atmosphere, the melting jig 1 is heated to iao'c.
1 heats the outside portion of the through hole 8a of the frame-like frame 8. This heating causes the outer portion of the through hole 8a to melt, and after cooling, the through hole 8a is in a closed state as shown in FIG.

<Effects of the Invention> As described above, the method for manufacturing a thin battery of the present invention is to close the through hole on the side surface of the frame under reduced pressure after adhering the exterior film and the frame under normal pressure. Therefore, it is possible to prevent the electrolyte from adhering to the adhesive surface between the exterior film and the frame-like frame, and to ensure the adhesion between the exterior film and the frame-like frame. Therefore, the sealing properties of the battery can be improved and the leakage resistance can be improved, and as a result, the reliability of the battery is increased. In addition, in addition to providing a through hole in the frame-like frame, the battery is placed under reduced pressure after the above-mentioned adhesion is completed, and the through-hole in the frame-like frame is closed in this state, so the pressure inside the battery can be reliably and sufficiently reduced. I can do something. As a result, there is an advantage that the adhesion between the current collector plate and the positive electrode mixture or the negative electrode is significantly increased, and the battery discharge performance is improved. Furthermore, since the time-consuming process of adhering the exterior film and the frame-like frame can be carried out under normal pressure, which is easy to work with, the workability is improved and the battery can be manufactured more easily.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a thin battery manufactured by the method of the present invention, FIGS. 2A and B are a plan view and a cross-sectional view showing a frame-like frame, and FIG. 3 is a frame-like frame. FIG. 3 is an explanatory diagram showing an example of a means for closing a through hole on a side surface. 2... Positive electrode mixture, 3... Negative electrode, 4.5... Current collector plate, 6.7... Exterior film, 8... Frame-shaped frame.

Claims (1)

[Claims] 1. A method for manufacturing a thin battery in which a power generation element is covered with two upper and lower exterior films, and the peripheral parts of the exterior films are bonded to each other via a frame-like frame, in which the frame-like frame is 1. A method for manufacturing a thin battery, comprising providing a through hole in a side surface, bonding the exterior film and the frame-like frame under normal pressure, and then closing the through hole under reduced pressure.