JPH03163750A - Manufacture of flat battery - Google Patents

Abstract

PURPOSE:To obtain a flat battery with excellent appearance and leak resistance with out causing deformation when the battery is shrunk by sealing the opening end of the container of the flat battery with a crimp die constituted of an R section and a taper section with a fixed radius of curvature for the seal shape on the inner face to be bent. CONSTITUTION:A pressing die 23 is lowered so that the lower face 23a of the die 23 is brought into contact with the upper face of a sealing plate 33, a crimp die 22 is lowered while the pressing die 23 is pressed with a fixed pressure, the R section 22c and taper section 22d on the inner face of the die 22 are brought into contact with the opening end 31a of a positive electrode container 31 and pressed, the opening end 31a is bent on a gasket 36 side, the linear section 22b of the crimp die 22 is brought into contact with the side wall outer face of a positive electrode container 31, and it is shrunk for sealing. Since the upper face of the sealing plate 33 is pressed at the time of sealing, the angle of the taper section 22d on the inner face of the crimp die 22 is preferably set to 10-40 deg. against the lower face 23a of the die 23. The caulking state on the periphery rising side face of the sealing plate 33 and the side wall inner face of the container 31 for the insulating gasket 36 and the caulking state on the periphery rising section upper face and the opening end inner face of the con tainer 31 can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a flat battery, and in particular, after a sealing plate that also serves as a terminal for another polarity is fitted into a container that also serves as a terminal for one polarity through an insulating gasket. This paper relates to a method for manufacturing flat batteries with an improved sealing process. [Prior art 1] In general, a flat battery is sealed by inserting a negative electrode sealing plate into the positive electrode container with a power generating element housed between a container that also serves as a one-polar terminal, such as a positive electrode container, and a sealing plate that also serves as a terminal of the other polarity, such as a negative electrode sealing plate. After fitting the container through an insulating gasket, a crimp mold was used to bend the open end of the container and reduce the diameter of the container. An example of a conventional method for manufacturing a flat battery using a crimp mold will be described with reference to FIGS. 4 and 5(a) and 5(b). Fig. 4 is a partial longitudinal cross-sectional view showing the structure of the sealing plate device, and Fig. 5 (a) and (b) are longitudinal cross-sectional views showing the sealing process. In FIG. 4, reference numeral 1 denotes a table on which a container containing a power generating element and a sealing plate are set at the time of sealing, and an annular crimp mold 2 is arranged above the table 1 so as to be movable up and down. The inner peripheral surface of the crimp mold 2, which is involved in sealing, consists of an insertion part 2a, a straight part 2b, and a radiused part 2c that is bent by contacting the open end of the container from the lower end side, and the radiused part 2c has a certain curvature. It has a radius. A pressing die 3 for pressing the upper surface of the sealing plate during sealing is inserted into the hollow part of the crimp die 2 so as to be movable up and down. To perform sealing using this sealing device, first see Figure 5 (
As shown in a), the positive electrode #112 is stored in the positive electrode container 11, and the negative electrode #14 is fixed to the negative electrode sealing plate 13, and the positive electrode container 11 and the negative electrode sealing plate 13 are placed between the positive electrode 12 and the negative electrode 14. They are placed facing each other with a separator 15 interposed therebetween and an insulating gasket 16 interposed therebetween. The positive electrode container 11 in this state is set on the Tefur 1. Next, as shown in FIG. 5(b), the pressing mold 3 is lowered to bring the lower surface 3a of the mold 3 into contact with the upper surface of the negative electrode sealing plate 13, and while pressing with a constant pressure, the crimping mold 3 is pressed down. The mold 2 is lowered and the rounded part 2C of the inner surface is pressed against the opening r4A11a of the positive electrode container 1l to bend this opening end 11a to open the gasket 16, and the straight part 2a of the crimp mold 2 is pressed against the side wall of the container 11. It seals by bringing it into contact with the outside surface and reducing its diameter. FIG. 6 shows a partial view of the flat battery manufactured in this manner.

[Problems to be Solved by the Invention] However, a battery manufactured by the conventional manufacturing method sealed using a crimp mold in which the radius of curvature of the rounded portion 2c is constant as described above has a problem with the insulating gasket 16 shown in FIG. The peripheral rising side surface 13a of the negative electrode sealing plate 13 and the positive electrode container 11 are in contact with each other.
It was difficult to sufficiently caulk both the internal measuring surface 11b of the negative electrode sealing plate 13, the upper surface 13b of the peripheral rising portion of the negative electrode sealing plate 13, and the inner surface of the open end 11a of the positive electrode container 11. The reason for this is that the radius of curvature of the sealing shape is constant, so when the radius of curvature of the rounded part 2C of the crimp mold 2 used in the upper part of the sealing process is large (the arc of the rounded part 2c is slow), the negative electrode sealing plate Although it is possible to improve the caulking condition between the peripheral edge rising round surface 13a of the negative electrode sealing plate 13 and the inner surface 11b of the positive electrode container 11a, the caulking condition between the peripheral edge rising portion upper surface 13b of the negative electrode sealing plate 13 and the inner surface of the opening end 11a of the positive electrode container 11 is not good. This tends to reduce leakage resistance. On the other hand, when the radius of curvature of the rounded part 2c of the crimp mold 2 used in the sealing process is small (the circular arc of the rounded part 2c is sharp), the positive electrode container 11 whose diameter is reduced by the straight part 2b of the crimp mold 2 However, deformation occurs due to the sharp radius of curvature of the radiused portion 2c, so if the radius of curvature of the radiused portion 2c is kept constant, it cannot be made smaller than a certain dimension. This invention has been made in order to solve the above-mentioned problems.The present invention has been made to solve the above-mentioned problems, and without causing deformation when the diameter of the container which also serves as a one-polar terminal is reduced, the inner surface of the side wall of the container that is in contact with the insulating gasket and the other-polarity terminal are sealed. The purpose of this invention is to provide a method for manufacturing a flat battery that can improve both the caulking condition of the rising edge of the plate and the caulking condition of the inner surface of the opening end of the container and the upper surface of the rising edge of the sealing plate. [Means for Solving the Problems] In order to achieve the above object, the present invention stores a power generation element between a container that also serves as a unipolar terminal and a sealing plate that also serves as an a-polar terminal, and connects the sealing plate to the container with an insulating gasket. In a method for manufacturing a flat battery, the method comprises: fitting the container through a crimp mold, bending the open end of the container inward using a crimp mold, and reducing the diameter of the container to seal the power generating element.
The crimp mold is characterized in that the opening end of the container is bent using an inner surface whose sealing shape consists of a rounded part and a tapered part having a constant radius of curvature.

[Function] According to the above manufacturing method, when sealing is performed using the Talimbu mold, the sealing shape of the inner surface to be bent at the open end of the container that also serves as a unipolar terminal is formed from a rounded part and a tapered part having a constant curvature diameter. This reduces the force applied to the open end of the positive electrode container during sealing and eliminates deformation, as well as the caulking condition of the four peripheral edges of the sealing plate against the insulating gasket and the inner surface of the wall of the container, as well as the sealing against the gasket. The upper surface of the rising edge of the plate and the inner surface of the opening end of the container can be caulked in a good manner, and a flat battery with excellent appearance and leakage resistance can be manufactured. [Embodiment] An embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a sectional view showing the sealing device of the same embodiment. 1st
In the figure, 21 is a table on which the container containing the power generation element and the sealing plate are set at the time of closing. An annular crimp mold 22 is arranged above the table 21 so as to be movable up and down. The inner circumferential surface of the crimp die 22 involved in sealing includes an insertion portion 22a, a straight portion 22b, and a straight portion 22b.
As will be described later, the rounded portion 22c has a constant radius of curvature and is bent by contacting the open end of the container, and a taper 22d. Further, a mold 23 is inserted into the hollow portion of the mold 22 so as to be movable up and down, for pressing the upper surface of the sealing plate when sealing the date.

Next, the process of sealing with the above-mentioned sealing device is shown in Figure 2 (a).
) (b). First, the positive electrode 32 is stored in a container, for example, the positive electrode container 31, which also serves as a one-polar terminal, and the negative electrode 34 is fixed to a sealing plate, such as the negative electrode sealing plate 33, which also serves as a terminal of the other polarity. A separator 35 is interposed between the positive electrode 32 and the negative electrode 43, and an insulating gasket 36 is interposed therebetween. Note that a positive electrode ring (not shown) is arranged on the upper surface of the positive electrode 32. The positive electrode container 31 containing the above-mentioned positive electrode 32 etc. is shown in FIG.
), set it on the table 21. Next, as shown in FIG. 6B, the press mold 23 is lowered to bring the lower surface 23a of the mold 23 into contact with the upper surface of the sealing plate 33, and the crimp mold 22 is pressed with a constant pressure. The curved part 22c and the tapered part 22d of the inner surface of the mold 22 are brought into contact with and pressed against the open end 31a of the positive electrode container 31, and the open end 31a is bent to open the gasket 36, and the straight part of the crimp mold 22 is pressed. 22b is brought into contact with the outer surface of the measuring wall of the positive electrode container 31, and the diameter is reduced to form a sealing plate. In this case, the bending of the open end 31a of the positive electrode container 31 by the crimp mold 22 and the caulking to the gasket 361I11 are performed in the latter half of the descent of the crimp mold 22. Figure 3 shows a flat battery removed from the sealing device after the sealing process. The angle of the tapered portion 22d on the inner surface of the crimp mold 22 is preferably 10'' to 40'' with respect to the lower surface 23a of the mold 23 in order to press the upper surface of the sealing plate 33 during sealing.

The reason for this is that if the angle exceeds 40 degrees, the tapered part 22d of the inner surface of the crimp mold 22 will be exposed to the positive electrode container 3 during the sealing process.
The force applied to the opening end 31a of No. 1 becomes weaker, and the third
In the flat type battery shown in the figure, the upper surface 33b of the rising edge of the negative electrode sealing plate 33 and the open end 31a of the positive electrode container 31 are not sufficiently caulked to the insulating gasket 36, which may cause problems in leakage resistance. On the other hand, if it is less than 10'', it is difficult to alleviate the force applied to the rounded part 22C and the tapered part 22d following the straight part 22b on the inner surface of the crimp mold 22 during the sealing process, and there is a risk of deformation.

When the manufacturing method described above is adopted, when sealing is performed using the clamp mold 22, the sealing shape of the inner surface of the positive electrode container 31 that should be bent has a rounded portion 22c and a tapered portion 22d having a constant radius of curvature.
By using the material, the force applied to the open end 31a of the positive electrode container 31 at the time of sealing is alleviated and deformation is eliminated, and the opening surface 33a of the rising edge of the negative electrode sealing plate relative to the insulating gasket 36 and the inner surface of the side wall of the positive electrode container 31 are 3
lb caulked state, and furthermore, the upper surface 33a of the peripheral edge rising part of the negative electrode sealing plate 33 and the positive electrode container 31 relative to the gasket 36.
The inner surface of the opening @ 31a can be caulked in a good condition, and a flat battery with excellent appearance and leakage resistance can be manufactured. The radius of curvature r between BC of the rounded part 22c shown in Fig. 1 is 0.61111, and the angle θ of the part of Taber between A and B is
According to the process shown in FIG. 2, the sealing device shown in FIG. Flat type battery (button type alkaline battery: LR11) shown in
30) was manufactured. The components and dimensions of the battery in this case are as follows. Positive electrode container 31; 0.3u thick nickel plated steel plate positive @3
2; Positive electrode mixture negative electrode sealing plate 33 consisting of manganese dioxide (positive electrode active material), graphite (conductive material), and sodium polyacrylate (binder); Cu plate, stainless steel plate, and Ni plate were sequentially laminated from the inner side. Thickness 0. 3mm clad plate, negative [! 34: Negative electrode mixture containing zinc powder, potassium hydroxide electrolyte, and sodium polyacrylate gelling agent, Separator 35: Two-layer structure sheet insulation of acetalized polyvinyl alcohol nonwoven fabric holding cellophane sheet and electrolyte Gasket: Polyethylene positive electrode ring (not shown); Formed from Ni Battery external shape: 1
1.5+111 Battery total height: 2.9 In addition, the radius of curvature r between BC of the rounded part 22c shown in Fig. 1 is 0.61111, and the angle θ of the tapered part between A and B is sealed at the closing date and time. Press the top of the board. Mold 2 for
10°, 20°, 30°, 4
Using a sealing device incorporating a crimp die 22 of o', so°, sealing was performed according to the process shown in FIG. This type was manufactured as an example. 500 of each of the five types of button-type alkaline manganese batteries obtained were heated at 60°C and 93% RH.
The number of leaking samples after storage for several days was investigated.

Table 1 shows the results.

In addition, in Table 1, the rounded portion 2C shown in FIG.
A button shape manufactured by the same method as in the example except that a sealing device incorporating a crimp die 2 having a constant curvature radius (r) of 0.81, which is the minimum radius of curvature that does not cause deformation, was used. The number of leaks for 500 alkaline manganese batteries (comparative example) is also listed for reference. According to Table 1, it can be seen that the leakage resistance of the battery sealed using the sealing device incorporating the crimp die of the present invention was significantly improved compared to the battery of the comparative example. It was also confirmed that the battery of this invention has a good appearance without deformation of the battery container. This invention is not limited to the above-mentioned embodiments, and different arrangements can be made without changing the gist. [Effects of the Invention] According to the present invention, the container that also serves as a one-polar terminal is not deformed when the diameter is reduced, and the inner surface of the side wall of the container that is in contact with the insulating gasket and the rising side surface of the peripheral edge of the sealing plate that also serves as the other-polarity terminal It is possible to improve both the caulking condition and the caulking condition of the inner surface of the opening end of the container and the upper surface of the peripheral rising portion of the sealing plate, and it is possible to provide a method for manufacturing a flat battery with excellent appearance and leakage resistance. ．．

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a sealing device used in a method for manufacturing a flat battery according to an embodiment of the present invention, and FIGS. 2(a) and (b)
3 is a cross-sectional view showing the sealing process in the same example, FIG. 3 is a partial vertical cross-sectional view of the flat battery obtained in the same example, and FIG. 4 is a sealing process used in an example of a conventional flat battery manufacturing method. FIGS. 5(a) and 5(b) are sectional views showing the sealing process in the same example, and FIG. 6 is a partial cross-sectional view taken along line 11 of the flat battery obtained in this example. 21...Table 22...Crimp mold 2
2a... Insertion part 22b... Straight part 22c.
...Tapered part 23a...Press die lower surface 32...Positive electrode 34...Negative electrode 36...Insulating gasket 23...Press die 31...Positive electrode container 33...Negative electrode sealing plate 35...・Separator

Claims (1)

[Claims] After storing a power generating element between a container that also serves as a one-polarity terminal and a sealing plate that also serves as a terminal of the other polarity, and fitting the sealing plate into the container via an insulating gasket, the open end of the container is inserted using a crimp mold. In the manufacturing method of a flat battery, in which the opening end of the container is bent inward and the diameter of the container is reduced to seal the power generation element, the sealing shape of the inner surface of the crimp mold to which the open end of the container is to be bent has a constant radius of curvature. 1. A method for manufacturing a flat battery, characterized in that sealing is performed using a rounded part and a tapered part.