JP3199060B2 - Flat organic electrolyte battery and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for thin devices such as wristwatches, calculators, memory cards, etc., or power sources for driving non-contact type IC card tags and the like, and power sources for memory backup. The present invention relates to an ultra-thin flat organic electrolyte battery set to 1 mm or less and a method for producing the same.

[0002]

2. Description of the Related Art A flat organic electrolyte battery (hereinafter, referred to as a flat battery) in which a power generating element using light metal is housed in a flat battery container has excellent reliability and high energy density. Power supply for driving various electronic devices,
In addition, it is suitably used as a power supply for backing up a memory.

In a general flat battery, as shown in FIG. 2, a sealing plate 11 having a U-shaped continuous portion provided on an outer peripheral edge is used. Such a flat battery is obtained by combining a gasket 13 with a sealing plate 11 and then closing the sealing plate 1.
The separator 14 is inserted in a state in which the negative electrode body 16 is press-fitted inside 1. On the other hand, after the positive electrode body 15 is disposed in the case 12 in the state of being opened at the top, and the electrolyte is injected,
The sealing plate 11 is placed on the positive electrode body 15, and the battery container is sealed by curling the open end of the case 12 inward.

[0004] Recently, with the reduction in the thickness of the housing of an electronic device, a reduction in the thickness of a flat battery disposed inside the device has also been required. Furthermore, in addition to electronic devices, the use of flat batteries as power sources for non-contact data tags or cards that store personal authentication, identification information, and financial information and transmit and receive such information in a non-contact state is being considered. ing. In these uses, it is desired to set the thickness of the battery container to 1 mm or less.

However, the flat battery shown in FIG. 2 has a problem that it is necessary to form a folded portion that connects the outer peripheral edge of the sealing plate in a U-shape, which makes it difficult to press work in a manufacturing stage. Further, there is a problem in that the dimensional accuracy due to the press working is reduced, and when the battery is completed, the liquid leakage resistance is poor.

A battery having the structure shown in FIG. 3 has been proposed as a battery in which such a problem is solved and the thickness of the battery is set to 1 mm or less. In FIG. 3, the sealing plate 21 is formed in a hat shape whose main surface has a convex portion projecting outward and a peripheral portion extending substantially parallel to the main surface. The case 22 is a gasket 23
The battery container is sealed by sandwiching the peripheral edge of the sealing plate 21 through the power generation element in which the negative electrode body 26 and the positive electrode body 25 are arranged to face each other with the separator 24 interposed therebetween. ing. The sealing plate 21 is formed in a hat shape, and its peripheral edge is formed to extend substantially parallel to the upwardly projecting convex portion.
1 does not have a U-shaped folded portion. For this reason, in addition to being easy to manufacture by press working, the dimensional accuracy is stable, and the occurrence of a problem due to the formation of the folded portion can be solved. Therefore, in the case of a thin flat battery in which the thickness of the battery container is set to 1 mm or less, a battery having the structure shown in FIG. 3 is preferable.

[0007]

However, the thin flat battery having the above structure has the following new problems. That is, the flat battery shown in FIG. 3 has a substantially L-shaped cross section so as to rise upward along the side surface from the bottom surface of the case 22 in the upper open state, and has a central portion where the power generation element is mounted. A ring-shaped gasket 23 punched into a circle is used. Further, after the gasket 23, the power generation element and the sealing plate 21 are respectively placed on the case 22, the opening end of the upper part of the case 22 is bent inward, and the peripheral edge of the sealing plate 21 is sandwiched via the gasket 23 to close the case. It is carried out. The gasket 23 thus arranged near the outer peripheral edge of the inner surface of the case 22
The thin flat battery shown in FIG. 3 is only sandwiched between the case 22 and the upper and lower surfaces of the flat peripheral portion of the sealing plate 21. The thin flat battery shown in FIG. As compared with a known flat battery having a portion, there is a problem that the liquid leakage resistance is inferior.

According to the present inventors' detailed examination, the flat battery of FIG. 2 has a portion where the gasket 13 is locally compressed at the lower end and the outer peripheral edge of the U-shaped folded portion. In the thin flat battery shown in FIG. 3, the gasket 23 includes the case 22 and the sealing plate 21.
And the gasket does not have a locally compressed portion, so that the electrolyte contained in the battery container is exposed to the contact surface between the gasket, the sealing plate 21 and the case 22. It has been found that since the electrolyte leaks through the existing minute gap, the electrolyte is inferior in leak resistance.

On the other hand, in the manufacturing process, since the battery container is a thin flat battery whose thickness is set to 1 mm or less, the sealing plate 21 and the case 22, which are the components of the battery container, are adapted to this. Also, the height of the gasket 23 becomes very low. For this reason, at the stage of placing the power generating element, the gasket 23 and the sealing plate 21 in the case 22, and at the stage of caulking and closing, a deviation in the radial direction is likely to occur, and the accuracy of positioning the gasket cannot be maintained. As a result, there is a problem that liquid leakage occurs and battery durability is reduced. Further, when the deviation in the radial direction becomes large, the sealing plate 21, the case 22, and the gasket 23 are not integrally combined at a predetermined position, so that there is a problem that the machine operation in the battery assembling process is reduced and the defective rate is increased.

Therefore, an object of the present invention is to solve the above-mentioned problems, and by improving the structure of the sealing portion, particularly the shape of the sealing plate and the case, the liquid leakage resistance and durability even in a thin shape of 1 mm or less. An object of the present invention is to provide a flat battery excellent in mass production and to obtain a flat battery manufacturing method excellent in mass productivity.

[0011]

In order to achieve the above object, a flat battery according to the first invention of the present application comprises a case which also serves as one electrode terminal, and a convex portion which also serves as the other electrode terminal and protrudes outward. and the convex portion and substantially parallel to extending peripheral edge and the sealing plate was made form, and to insulate the said case and said sealing plate, it seals the power generating element in a battery container having a ring-shaped gasket, The sealing plate has an annular concave portion protruding toward the bottom surface side of the case at a peripheral portion, and the case is located on the inner surface of the case and at the portion of the bottom surface where the gasket is disposed, and the annular concave portion of the sealing plate. On the other hand, it has an annular convex portion which is located on the outer peripheral side or the inner peripheral side and protrudes upward, and wherein the annular concave portion and the annular convex portion locally compress the gasket. It is.

[0012] According to the above configuration, since the portion abutting on the annular concave portion and the annular convex portion locally compresses the gasket, the compressive stress increases the degree of adhesion at the portion, and the gasket and the case or the sealing plate may be in contact with each other. Since the minute gap existing on the contact surface is crushed, the movement of the electrolyte toward the surface of the battery container following the gap is hindered, and the occurrence of liquid leakage is greatly suppressed. Here, the cross-sectional shape of the annular concave portion and the annular convex portion formed on the peripheral edge lower surface of the sealing plate and the bottom surface inside the case is a wedge shape with a sharp tip, or
The shape may be any shape as long as the gasket is locally compressed in the thickness direction of the battery.

Further, the second invention of the present application is characterized in that the power generating element is hermetically sealed by a case also serving as one electrode terminal, a sealing plate also serving as the other electrode terminal, and a gasket insulating the case and the sealing plate. Concerning a method for manufacturing a flat organic electrolyte battery having a convex portion in which a sealing plate protrudes outward and a peripheral portion extending substantially in parallel with the convex portion , a manufacturing method including each step in the following order, 1. An annular concave portion protruding toward the bottom surface of the case is formed at the peripheral edge portion of the sealing plate, and an annular convex portion protruding upward is formed at a portion where the gasket is located on the bottom surface of the case in an upper open state. Process, 2. 2. A step of placing a power generating element, a gasket, and a sealing plate inside the case; The method is characterized in that the opening end of the case is bent inward, the peripheral edge of the sealing plate is sandwiched by the case via a gasket, and the battery container is fitted and sealed.

According to the above-mentioned manufacturing method, prior to placing the power generating element and the gasket in the case, an annular convex portion is previously formed on the bottom surface of the case by press working, and this is used as a positioning member to arrange the power generating element and the gasket. By doing so, it is possible to prevent radial displacement within the case.

Further, before the fitting, the upper opening end of the case is bent inward, and only the case is pressed to form an annular convex portion in advance, so that the shape of the annular convex portion is reduced. The dimensional accuracy is greatly improved. For this reason, compared to the case of performing press working after fitting, the protrusion height of the annular convex portion is insufficient, and the occurrence of liquid leakage due to a small degree of local compression and the protrusion height are reduced. It is possible to prevent the gasket from being damaged due to an excessively large size and the occurrence of a short circuit between the case and the sealing plate at the damaged portion.

On the other hand, by providing the annular concave portion in advance on the sealing plate side to form a portion where the gasket is locally compressed at the peripheral portion of the sealing plate, the reliability against liquid leakage can be greatly improved. . Further, an annular convex portion on the case side is provided on the center side or the outer peripheral side of the bottom surface of the case with respect to the annular concave portion so that the annular concave portion and the annular convex portion are not in contact with each other. Is accurately positioned. Here, since the peripheral portion of the sealing plate adopts a shape sandwiched by the case via the gasket, it cannot be formed after fitting and sealing with the case, Since the sealing plate is also used as a positioning member when placing the sealing plate, it is necessary to form the annular concave portion in the sealing plate in advance and then place the sealing plate inside the case. Further, instead of the annular concave portion, a convex portion protruding upward may be formed on the peripheral edge portion of the sealing plate, and the gasket may be locally compressed. However, it is necessary to form the convex portion near the outer peripheral edge of the peripheral portion and to dispose it so as to face the inner surface of the case via a gasket, and high dimensional accuracy is required. It is preferable to apply the present invention to a flat battery having a relatively large diameter in which the width of the folded portion of the case folded from the periphery toward the center can be set large.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described for understanding the present invention. The embodiment described below is an example embodying the present invention, and does not limit the technical scope of the present invention.

A flat battery according to the present invention will be described with reference to FIG.
explain. In the drawing, a case 2 also serves as one electrode terminal, and a sealing plate 1 also serving as the other electrode terminal, and a power generation element is sealed via a gasket 3 which insulates and seals the both. The power generating element is configured such that a positive electrode body 5 and a negative electrode body 6 are opposed to each other with a separator 4 interposed therebetween, and an electrolytic solution is combined therewith.

As is apparent from the longitudinal sectional view, the sealing plate 1 has a convex portion 7 protruding outward and a flat peripheral portion 8 extending substantially parallel to the convex portion. Further, an annular concave portion 9 which is an annular concave portion protruding toward the bottom surface of the battery case is formed in the peripheral portion 8, and its cross-sectional shape may be an uneven shape instead of the wedge shape shown in FIG. . An annular convex portion 10 protruding upward is formed on the peripheral edge of the bottom surface of the case 2, and the formation position thereof is either the center direction side or the outward direction side of the case bottom surface with respect to the annular concave portion. And the gasket 3 is disposed on the upper surface thereof. The cross-sectional shape of the annular convex portion in the case 2 is preferably a wedge shape or an uneven shape like the sealing plate 1.

According to the configuration of the present invention as described above, when the upper end of the case 2 that is open is bent inward and fitted with the swaged seal, the sealing plate 1 is closed. The wedge-shaped annular concave portion 9 provided on the flat peripheral portion 8 and the wedge shape 10 provided on the peripheral bottom surface of the case 2 bite into the gasket 3, and the compression ratio of the gasket 3 can be increased. For this reason, the sealing performance between the sealing plate 1, the case 2, and the gasket 3 is improved, and the liquid leakage resistance and durability of the obtained battery are also improved.

The flat battery according to the present invention is particularly aimed at reducing the thickness of the battery container, and the thickness of each of the sealing plate 1 and the case 2 is 0.20 mm.
The thickness is preferably 1.0 mm or less, and the thickness of the obtained obtained flat battery is preferably 1.0 mm or less.

Further, in order to secure the sealing performance of the battery by local compression, it is necessary to set a compression rate suitable for the material of the ring-shaped gasket to be used. The material of the gasket 3 applied to the flat battery according to the present invention having the organic electrolyte in the electrolyte and insulating the case 2 and the sealing plate 1 is polyphenylene sulfide resin, polyethylene terephthalate resin, polypropylene resin, polyethylene resin. Preferably, there is. Among them, it is particularly preferable to use a polyphenylene sulfide resin from the viewpoint of securing the battery sealing properties even in a wide operating temperature range and a high humidity environment.

Generally, the preferable compression ratio of the ring-shaped gasket is greatly related to the mechanical properties such as the bending strength of the material. The bending strength (specified in JIS D790) of each material is about 1 for polyphenylene sulfide resin.
200 kgf / cm ^2, the case of polyethylene terephthalate resin, about 1000 kgf / cm ^2, for polypropylene resin, about 400 kgf / cm ^2, when the polyethylene resin is about 300 kgf / cm ^2.

Therefore, the ratio of the thickness of the gasket in the sealed state to the thickness of the gasket in the unsealed state is defined as the compression ratio of the gasket, and the compression ratio of the locally compressed portion in the annular concave portion and the annular convex portion is examined. did. Here, the compression ratio is a ratio of the degree of reduction in the thickness in the sealed state with respect to the gasket in the unsealed state, and is determined according to the following equation. That is, the compression ratio (%) = ((thickness in unsealed state−thickness in sealed state) / thickness in unsealed state) × 100.

From this study, the compressibility of the ring-shaped gasket suitable for each material is 3 to 40% for polyphenylene sulfide resin, 5 to 50% for polyethylene terephthalate resin, and 5 to 50% for polypropylene resin. Compression rate 10-60%, in case of polyethylene resin,
The compression ratio was 15 to 70%. If the compression ratio of each material is smaller than the appropriate range, the compression of the ring-shaped gasket will be insufficient, and if it is too large, the compression limit will be exceeded and the ring-shaped gasket will be cracked. The characteristics deteriorate. Also, it can be said that as the bending strength is higher, the appropriate compression ratio of each material is lower, and the range becomes narrower.

The material applied to each component other than the gasket may be a conventionally used material. Therefore, as the material of the case 2 also serving as one electrode terminal and the sealing plate 1 also serving as the other electrode terminal, for example, stainless steel having excellent corrosion resistance is preferable. The separator 4 is made of, for example, a nonwoven fabric made of polypropylene or cellulose, or a porous polypropylene or polyethylene film, and the positive electrode and the negative electrode may be those applied to a known organic electrolyte battery.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, as one embodiment of the present invention, the present invention will be described in detail with respect to a flat type lithium graphite fluoride battery using graphite / lithium fluoride as a power generating element. It is not limited.

Example 1 As Example 1, a flat battery having the shape shown in FIG. The sealing plate 1 also serves as a negative electrode terminal, and is made of stainless steel. The sealing plate 1 has a flat peripheral portion, and an annular concave portion having a wedge-shaped cross section is formed in the peripheral portion. Similarly, Case 2
Also serves as a positive electrode terminal, and is formed of stainless steel. An annular convex portion having a wedge shape is formed on the peripheral edge of the bottom surface of the case 2. The gasket 3 uses a film-like polyphenylene sulfide resin. When the gasket 3 is placed in the unsealed case 2 that is open at the top, the gasket 3 has a substantially L-shaped cross section that is bent upward from the bottom surface of the case 2 toward the end of the opening. The central portion is formed in a ring shape punched out in a circular shape. At the closing stage,
It is bent inward together with the opening of the case 2 and sandwiches the peripheral edge 8 of the sealing plate 1.

The power generating elements housed in the battery container composed of the above-mentioned components are composed of the positive electrode body 6, the negative electrode body 5, the separator 4, and the organic electrolyte. Separator 4
Is made of a nonwoven fabric made of polypropylene resin, and separates the negative electrode body 6 and the positive electrode body 5. The positive electrode body 5 is formed by adding water to a mixed powder of fluorinated graphite, carbon as a conductive material, and a binder of a fluororesin, kneading the mixture, granulating the mixture, drying the mixture, and pressure-molding to a certain size. It is formed into a pellet. The negative electrode body 6 is formed by punching foil-shaped metallic lithium into a predetermined shape. Further, in the organic electrolyte, an equal volume mixed solvent of gamma butyrolactone and 1,2-dimethoxyethane,
What melt | dissolved lithium borofluoride at the ratio of 1 mol / l was used.

Next, the manufacturing method will be described. The positive electrode body 5 and the separator 4 were filled in the case 2 in which an annular convex portion was formed in advance by press working, and an organic electrolyte was injected. A gasket 3 was also arranged along the peripheral edge of the bottom surface of the case 2. Next, a negative electrode body 6 punched into a predetermined shape is adhered to the inner surface of the case 2 in which the annular concave portion has been revised in the peripheral portion 8 in advance, and placed on the separator 4 arranged in the case 2 in this state. I do. The flat battery having the cross-sectional structure shown in FIG. 1 was prepared by bending the opening of the case 2 inward and sealing it.

Here, the thickness of the case and the sealing plate is 0.1 mm, the thickness of the gasket is 0.25 mm, the gasket compressibility in the annular concave portion and the annular convex portion after sealing is 20%, and the diameter is 20.0 mm, thickness 1.
0 mm. Here, the compression ratio of the gasket is
A ratio representing the thickness of the gasket at the locally compressed portion with respect to the thickness of the gasket in the unsealed state is set as a ratio representing the thickness of the gasket. (Comparative Example 1) A flat battery having the same configuration as in Example 1 except for using a sealing plate having only a plane substantially parallel to the portion was prepared.

(Comparative Example 2) As Comparative Example 2, a case having a flat bottom shape was used without providing a wedge-shaped annular convex portion at the periphery of the bottom surface, and the other configuration was the same as that of Example 1. A flat battery having the above was prepared.

(Comparative Example 3) As Comparative Example 3, a case having no annular convex portion and a sealing plate having no annular concave portion were used.
Other configurations were the same as those of the first embodiment, that is, FIG.
A flat battery having the cross-sectional structure shown in FIG.

Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3
For each of the batteries, 1000 batteries were prepared. At this time,
Count the number of defective batteries caused by radial displacement when fitting the sealing plate, gasket, case in the battery assembly process,
The defect rate was calculated. The defective rate was determined according to (the number of defective batteries / the number of assembled batteries) × 100 (%). The results are shown in (Table 1).

Next, a thermal shock test was carried out using 100 of each of the obtained batteries. This thermal shock test was -10
Holding at 1 ° C. for 1 hour and then holding at 60 ° C. for 1 hour was defined as one cycle, and a predetermined cycle was repeated.
To confirm the state of liquid leakage, the battery was taken out after 120 and 240 cycles, magnified 10 times with a microscope, and visually checked for the occurrence of liquid leakage on the battery surface. The leak rate is calculated according to (Equation 2), and the results are shown in (Table 1). (Equation 2) Leakage generation rate (%) = (Number of leaked batteries / Number of test batteries) × 100

[0036]

[Table 1]

From the results shown in Table 1, it is insufficient to secure the leakage resistance of the battery only by providing a wedge shape on only one of the flat peripheral portion of the sealing plate and the bottom of the peripheral portion of the case. The battery failure rate in the assembly process is also large. However, it was found that by providing the wedge shape on both the flat peripheral portion of the sealing plate and the bottom surface of the peripheral portion of the case, the battery was excellent in liquid leakage resistance and the battery failure rate in the assembly process could be reduced.

Next, an appropriate compression ratio depending on the material of the ring-shaped gasket was examined.

(Examples 2 to 4) Next, the local compressibility of the gasket at the portion where the annular convex portion of the case and the annular concave portion of the sealing plate abut on the gasket was examined. As Examples 2 to 4, using a ring-shaped gasket made of polyphenylene sulfide resin as in Example 1, by changing the shape of the annular concave portion and the annular convex portion formed in the sealing plate and the case, The compression ratio of the gasket was changed. In the same embodiment, the compression ratios in the annular convex portion and the annular concave portion were set to have the same value. The compression ratio of the gasket was determined in Example 2.
Is set to 3%, in the third embodiment to 10%, and in the fourth embodiment to 40%. Example 1 is the same as Example 1 except for the compression ratio of the gasket.
100 flat batteries were prepared in the same manner as described above.

(Comparative Examples 4 and 5) As Comparative Examples 4 and 5, flat batteries in which the compression ratio of the gasket was set so as to be out of the range set in Examples 2 to 4 were used. Created. The gasket is formed in a ring shape using polyethylene terephthalate resin as in the first embodiment. The compression ratio of the gasket was 2 in Comparative Example 4.
%, And 45% in Comparative Example 5.
Except for the compression ratio of the gasket, 100 flat batteries were manufactured in the same manner as in Example 1 except for the configuration.

Next, the thermal shock test was performed on Examples 2 to 4, Comparative Example 4 and Comparative Example 5. In this thermal shock test, holding at -10 ° C for 1 hour and then holding at 60 ° C for 1 hour was defined as one cycle, and a predetermined cycle was repeated. To confirm the state of liquid leakage, the battery was taken out after 120 and 240 cycles, magnified 10 times with a microscope, and visually checked for the occurrence of liquid leakage on the battery surface. The leak rate is calculated according to the above (Equation 2), and the results are shown in (Table 2).

[0042]

[Table 2]

From the results shown in Table 2, it was found that when the material of the ring-shaped gasket was polyphenylene sulfide resin, the compression ratio was excellent at 3 to 40%.

(Examples 5 to 8) Next, when polyethylene terephthalate is used as the gasket material, local compression of the gasket at a position where the annular protrusion of the case and the annular recess of the sealing plate abut on the gasket. The rate was examined. As Examples 5 to 8,
A ring-shaped gasket made of polyethylene terephthalate is used in place of the polyphenylene sulfide resin as the gasket material of Example 1, and the shape of the annular concave portion and the annular convex portion formed on the sealing plate and the case is changed. The compression ratio was changed. In the same embodiment, the compression ratios in the annular convex portion and the annular concave portion were set to have the same value.

The compression ratio of the gasket is set to 5% in the fifth embodiment, 10% in the sixth embodiment, 25% in the seventh embodiment, and 50% in the eighth embodiment. Except for the material and the compression ratio of the gasket, 100 flat batteries were prepared in the same manner as in Example 1 except for the configuration.

(Comparative Example 6 and Comparative Example 7) As Comparative Example 6 and Comparative Example 7, when the gasket material was polyethylene terephthalate resin, the gasket material was out of the range set in Examples 5 to 8. A flat battery with a gasket compression ratio set was prepared. The gasket is formed in a ring shape using polyethylene terephthalate resin. The compression ratio of the gasket was 3 in Comparative Example 6.
%, And 55% in Comparative Example 7.
Except for the compression ratio of the gasket, 100 flat batteries were manufactured in the same manner as in Example 1 except for the configuration.

Next, a thermal shock test was performed on Examples 5 to 8, and Comparative Examples 6 and 7. In this thermal shock test, holding at -10 ° C for 1 hour and then holding at 60 ° C for 1 hour was defined as one cycle, and a predetermined cycle was repeated. To confirm the state of liquid leakage, the battery was taken out after 120 and 240 cycles, magnified 10 times with a microscope, and visually checked for the occurrence of liquid leakage on the battery surface. The leak rate is calculated according to the above (Equation 2), and the results are shown in (Table 3).

[0048]

[Table 3]

From the results shown in Table 3, when the material of the ring-shaped gasket is polyethylene terephthalate resin,
It can be seen that the compression ratio is preferably in the range of 5 to 50%.

(Examples 9 to 12) Next, when the gasket material is a polypropylene resin, local compression of the gasket at a position where the annular protrusion of the case and the annular recess of the sealing plate abut on the gasket. The rate was examined. In Examples 9 to 12, a ring-shaped gasket made of a polypropylene resin was used instead of the polyphenylene sulfide resin as the gasket material of Example 1, and an annular concave portion and an annular convex portion formed on the sealing plate and the case. The compression ratio of the gasket was changed by changing the shape of the gasket. In the same embodiment, the compression ratios in the annular convex portion and the annular concave portion were set to have the same value.

The compression ratio of the gasket was 10% in the ninth embodiment, 15% in the tenth embodiment, and
In Example 1, 30%, and in Example 12, 60%
% Is set. Except for the material and the compression ratio of the gasket, 100 flat batteries were manufactured in the same manner as in Example 1 except for the configuration.

(Comparative Examples 8 and 9) As Comparative Examples 8 and 9, when the gasket material was a polypropylene resin, the gasket was set so as to be out of the range set in Examples 9 to 12. A flat battery having a compression ratio set as follows. The gasket is formed in a ring shape using a polypropylene resin. The compression ratio of the gasket was set to 5% in Comparative Example 8 and to 65% in Comparative Example 9. Except for the compression ratio of the gasket, 100 flat batteries were manufactured in the same manner as in Example 1 except for the configuration.

Next, a thermal shock test was performed on Examples 9 to 12, Comparative Example 8 and Comparative Example 9. In this thermal shock test, holding at -10 ° C for 1 hour and then holding at 60 ° C for 1 hour was defined as one cycle, and a predetermined cycle was repeated. Confirmation of the state of liquid leakage is 120 and 240
After the cycle, the battery was taken out, magnified by a microscope at a magnification of 10 times, and visually checked for occurrence of liquid leakage on the battery surface. The leak rate is calculated according to the above (Equation 2), and the results are shown in (Table 4).

[0054]

[Table 4]

From the results shown in Table 4, when the material of the ring-shaped gasket is polypropylene resin, the compression ratio is 10%.
It is understood that it is preferable to be in the range of 〜60%.

(Examples 13 to 16) Next, when the gasket material is polyethylene resin, local compression of the gasket at a position where the annular projection of the case and the annular recess of the sealing plate abut on the gasket. The rate was examined. In Examples 13 to 16, a ring-shaped gasket made of polyethylene resin was used instead of the polyphenylene sulfide resin as the gasket material of Example 1, and an annular concave portion and an annular convex portion formed on the sealing plate and the case. By changing the shape of the gasket, the compression ratio of the gasket was changed. In the same embodiment, the compression ratios in the annular convex portion and the annular concave portion were set to have the same value.

The compression ratio of the gasket is 15% in Example 13, 20% in Example 14, 35% in Example 15, and 7% in Example 16.
It is set to 0%. Except for the material and the compression ratio of the gasket, 100 flat batteries were manufactured in the same manner as in Example 1 except for the configuration.

(Comparative Examples 10 and 11) Comparative Example 10
And as Comparative Example 11, a flat battery in which the compression ratio of the gasket was set so that the gasket material was out of the range set in Examples 13 to 16 when the gasket material was a polyethylene resin was produced. The gasket is formed in a ring shape using a polyethylene resin. The compression ratio of the gasket is set to 10% in Comparative Example 10 and to 75% in Comparative Example 11. Except for the compression ratio of the gasket, 100 flat batteries were manufactured in the same manner as in Example 1 except for the configuration.

Next, Examples 13 to 16 and Comparative Example 1
0 and Comparative Example 11 were subjected to a thermal shock test. In this thermal shock test, after holding at -10 ° C for 1 hour,
The holding for one hour at 1 was defined as one cycle, and the predetermined cycle was repeated. To confirm the state of liquid leakage, the battery was taken out after 120 and 240 cycles, magnified 10 times with a microscope, and visually checked for the occurrence of liquid leakage on the battery surface. The leak rate is calculated according to the above (Equation 2), and the results are shown in (Table 5).

[0060]

[Table 5]

According to the results of Table 5, when the material of the ring-shaped gasket is polyethylene resin, the compression ratio is 15 to
It is understood that it is preferable to be in the range of 70%.

[0062]

As described above, according to the present invention, a sealing plate,
By improving the shape of the case, it is possible to provide a flat organic electrolyte battery excellent in liquid leakage resistance and durability even in a thin shape of 1 mm or less, and to obtain a flat battery manufacturing method excellent in mass productivity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flat organic electrolyte battery according to the present invention.

FIG. 2 is a longitudinal sectional view of a thin flat organic electrolyte battery.

FIG. 3 is a longitudinal sectional view of a flat battery using a sealing plate having a U-shaped folded portion.

[Explanation of symbols]

 1, 11, 21 Sealing plate 2, 12, 22 Case 3, 13, 23 Gasket 4, 14, 24 Separator 5, 15, 25 Positive element 6, 16, 26 Negative element 9 Annular concave part 10 Annular convex part

Continuing from the front page (72) Inventor Mitsuru Okaku 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-8-339785 (JP, A) JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 2/02-2/08

Claims (7)

(57) [Claims] 1. A case also serving as one electrode terminal, serves as the other electrode terminal, the convex portion protruding outward the protrusion and the sealing plate peripheral edge portion substantially extending in parallel is made form, and said casing A flat battery in which a power generation element is hermetically sealed in a battery container provided with a ring-shaped gasket that insulates the sealing plate, wherein the sealing plate has an annular recess at a peripheral edge thereof protruding toward a bottom surface of the case. Wherein the case is located on the inner surface of the case and on the bottom surface where the gasket is disposed, on the outer peripheral side or the inner peripheral side with respect to the annular concave portion of the sealing plate, and an annular convex portion protruding upward. Wherein the annular concave portion and the annular convex portion locally compress the gasket. 2. The sealing plate and the case each have a thickness of 0.20 mm or less, and the battery container has a thickness of 1.20 mm or less.
The flat organic electrolyte battery according to claim 1, which has a thickness of 0 mm or less. 3. The gasket is made of a polyphenylene sulfide resin, and at a portion where the gasket comes into contact with the annular concave portion of the sealing plate and the annular convex portion of the case, the compression ratio represented by (Equation 1) is 3 to 40%. The flat organic electrolyte battery according to claim 1. (Equation 1) Compressibility (%) = ((Gasket thickness in unsealed state−Gasket thickness in sealed state) / Gasket thickness in unsealed state) × 100 4. The gasket is made of polyethylene terephthalate resin, and a compression ratio represented by (formula 1) is 5 to 50% at a portion where the gasket comes into contact with the annular concave portion of the sealing plate and the annular convex portion of the case. The flat organic electrolyte battery according to claim 1. 5. The gasket is made of a polypropylene resin, and a compression ratio represented by (Equation 1) is 10 to 60% at a portion where the gasket contacts the annular concave portion of the sealing plate and the annular convex portion of the case. Item 3. The flat organic electrolyte battery according to Item 1 or 2. 6. The gasket is made of polyethylene resin, and a compression ratio represented by (formula 1) is 15 to 70% at a portion where the gasket comes into contact with the annular concave portion of the sealing plate and the annular convex portion of the case. Item 3. The flat organic electrolyte battery according to Item 1 or 2. 7. A power generation element is sealed by a case also serving as one electrode terminal, a sealing plate also serving as the other electrode terminal, and a gasket insulating the case and the sealing plate.
The sealing plate is a method of manufacturing a flat-shaped organic electrolyte battery having a peripheral edge substantially extending parallel to the projecting portion projecting outward, and the convex portion, protruding on the bottom side of the case to the sealing plate periphery Forming a ring-shaped concave portion, a step of forming a ring-shaped convex portion on the bottom surface of the case in an upper open state, and projecting upward at a portion where a gasket is arranged, a power generating element inside the case, A step of placing a gasket and a sealing plate, and bending the open end of the case inward,
A method of manufacturing a flat organic electrolyte battery, comprising: a step of sandwiching a peripheral portion of the sealing plate with the case via a gasket, fitting a battery container, and sealing the battery container.