JP2011129253A - Coin-type cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coin-type cell that includes a cell-inside case, with a guard in a marginal part and that attains a stable long-term usage, without distorting the guard of the marginal part of the cell-inside case at sealing. <P>SOLUTION: The coin cell includes the cell-inside case 17 having the guard in the marginal part, a positive electrode 15, a separator 14, a negative electrode 16 and an electrolyte inside. The coin cell is sealed by a positive electrode case 12 and a sealing plate 11 via a gasket 13, provided on the guard 17a of the cell-inside case 17. In a lower part of the guard 17a of the marginal parts of the cell-inside case 17, a reinforcing rib 17b that prevents the guard 17a from being distorted by pressing force at sealing is provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coin-type battery in which a power generation element is sealed by a positive electrode case, a sealing plate and a gasket.

  Coin-type batteries have been used mainly in electronic devices because of their high energy density per volume and high voltage. In recent years, due to the rapid cordless and portable use of portable electronic devices, the demand for coin-type batteries has increased as a power source for driving them. Further, with the increase in current consumption of these portable electronic devices, larger capacity batteries, In addition, the reliability of the sealing portion that can be used stably for a long time is also required. In the coin-type battery, in order to improve the discharge capacity and reliability, the shape of the positive electrode case, the sealing plate, the positive electrode ring, and the gasket material are important points.

  As shown in FIG. 7, the conventional basic structure of the coin-type battery is that the positive electrode 5 and the negative electrode 6 are arranged to face each other with the separator 4 interposed between them, and an electrolyte is filled between the positive electrode case 2 and the positive electrode 5. The positive electrode ring 7 is disposed, the sealing plate 1 is disposed in the opening of the positive electrode case 2 via the gasket 3, and the upper end of the opening of the positive electrode case 2 is bent inward, so that the crimping process is performed. The battery has a shape appearance.

  In order to design a coin-type battery having a high battery height while following the conventional structure, a method of increasing the length of the folded portion 1a of the sealing plate 1 as shown in FIG. 8, and the folding of the sealing plate 1 as shown in FIG. Examples include a method of shortening the length of the portion 1a and reducing the height of the positive electrode case 2 to seal, and a method of increasing the bottom thickness 3a of the gasket 3 as shown in FIG. However, as apparent from FIGS. 8 and 10, the space of the caulking portion is large, and effective use of the internal volume of the battery, such as that used for the electrolyte filling space, has not been achieved.

  In order to solve these problems, the following measures are taken. That is, the battery case 7 as shown in FIG. 11 is provided, and the gasket 3 and the folded portion 1a of the sealing plate 1 are arranged and sealed on the peripheral edge 7a (see, for example, Patent Document 1), FIG. The side of the opening of the positive electrode case 2 as shown in FIG. 2 is scraped off to form a bulging portion 2a protruding in the center direction, and the gasket 3 and the folded portion 1a of the sealing plate 1 are arranged and sealed (for example, Patent Document 2) exists.

Japanese Patent Laid-Open No. 2-79366 JP-A-11-102672

  However, in the configuration of Patent Document 1, a force is applied to the flange 7a at the peripheral edge of the battery inner case 7 at the time of sealing, and the force at the time of sealing cannot be sufficiently supported, and as shown in FIG. There is a possibility that the flange 7a at the peripheral edge of the case 7 is deformed downward.

In recent years, materials for the gasket 3 have been studied in order to continue a stable sealing state at a higher temperature for a longer period of time. Conventionally, polypropylene resins have been used for general purposes, but in recent years fillers have been added to polypropylene resins. And engineering plastic resins are being adopted. Some of these materials have very high flexural strength and flexural modulus compared to the polypropylene resin and the like. As an example, when the bending elastic moduli of polypropylene resin and polyphenylene sulfide resin (PPS) are compared, they are 1 to 2 Gpa and 10 to 20 Gpa, respectively, and polyphenylene sulfide resin is a material that is very difficult to compress.

  When these materials are sealed as the gasket 3, the gasket 3 itself is hard and difficult to be compressed, so that the flange 7 a at the peripheral edge of the battery inner case 7 is more easily deformed as shown in FIG. As a result, the liquid leakage resistance and long-term reliability are lowered. If the thickness of the battery inner case 7 is increased to increase the rigidity and strength of the material to prevent deformation of the peripheral edge 7a of the battery inner case 7 at the time of sealing, the battery inner case 7 occupies the battery inner volume. Since the volume ratio increases, the filling amount of the positive electrode active material decreases, and the discharge capacity decreases.

  In the configuration of Patent Document 2, the gasket 3 is disposed on the bulging portion 2a of the positive electrode case 2, so that the thickness of the positive electrode case 2 is increased in order to sufficiently compress the bottom of the gasket 3 at the time of sealing. In addition, it is necessary to bulge a sufficient amount by indentation processing, leading to an increase in material cost and a decrease in discharge capacity accompanying a decrease in battery internal volume.

  An object of the present invention is to provide a coin-type battery that can be used stably for a long period of time without deformation of the collar portion of the battery inner case even when sealed.

  In order to achieve the above object, the present invention provides a battery inner case, a positive electrode, a separator, a negative electrode, and an electrolyte solution having a rim at the periphery, and a positive electrode through a gasket disposed on the ridge of the battery inner case. A coin-type battery sealed by a case and a sealing plate is characterized in that a reinforcing rib for preventing deformation of the heel by a pressing force at the time of sealing is provided at a lower portion of the rim of the inner case of the battery.

  According to the present invention, by providing the reinforcing ribs at the lower part of the rim of the peripheral portion of the battery inner case, it is possible to have the rigidity and strength enough to receive the force at the time of sealing, and therefore compress the bottom of the gasket at the time of sealing. It is possible to provide a coin-type battery having a sufficient amount and a small variation, and having good leakage resistance.

  As described above, according to the present invention, in a coin-type battery, a coin-type battery is provided that has a sealing rib stabilized by providing a reinforcing rib at the lower part of the peripheral edge of the battery inner case, and has improved leakage resistance. be able to.

Half sectional view of a coin-type battery according to an embodiment of the present invention The top view of the battery inner case which concerns on embodiment of this invention Sectional view of the battery inner case according to the embodiment of the present invention taken along line AA shown in FIG. Sectional view of the battery inner case according to the embodiment of the present invention taken along line BB shown in FIG. Half sectional view of a coin-type battery according to another embodiment of the present invention Half sectional view of a coin-type battery according to another embodiment of the present invention Half sectional view of a conventional coin-type battery Half sectional view of a conventional coin-type battery Half sectional view of a conventional coin-type battery Half sectional view of a conventional coin-type battery Half sectional view of a conventional coin-type battery Half sectional view of a conventional coin-type battery Half sectional view of a conventional coin-type battery

  According to a first aspect of the present invention, there is provided a battery case, a positive electrode, a separator, a negative electrode, and an electrolyte solution having a rim at the periphery, and a positive electrode case through a gasket disposed on the ridge of the battery case. In the coin-type battery sealed with a sealing plate, a reinforcing rib for preventing deformation of the heel by a pressing force at the time of sealing is provided at the lower part of the rim of the inner case of the battery. With this configuration, it is possible to provide a coin-type battery with a stable sealing and excellent liquid leakage resistance.

  According to a second aspect of the present invention, there is provided the coin-type battery according to the first aspect, wherein the reinforcing rib is formed in a groove shape formed in the flange of the battery inner case and the side wall of the battery inner case. By forming the groove-shaped reinforcing ribs by extrusion, it can be easily provided uniformly over the entire circumference of the battery inner case, providing a coin-type battery with stable sealing and excellent leakage resistance. can do.

  According to a third aspect of the present invention, in the second aspect, in the groove-shaped reinforcing rib formed on the side wall of the battery inner case and the battery inner case, the outermost position of the groove of the battery inner case It is a coin-type battery formed so that it may become inside from the lower end top part of the folding | turning part of a board. With this configuration, it is possible to further stabilize the sealing and improve the liquid leakage resistance.

  A fourth invention according to the present invention is the coin battery formed in the first invention so that the thickness of the reinforcing rib is larger than the plate thickness of the battery inner case. With this configuration, the strength of the reinforcing rib can be improved, and a coin-type battery excellent in leakage resistance can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  FIG. 1 is a half sectional view of a coin-type battery according to an embodiment of the present invention. A positive electrode 15 and a negative electrode 16 are arranged opposite to each other with a separator 14 therebetween, filled with an electrolyte solution, a sealing plate 11 is arranged in an opening of the positive electrode case 12 via a gasket 13, and a peripheral edge of the battery case 17 Reinforcing ribs 17b are provided in the lower part of the flange 17a of the part, and the upper end of the opening of the positive electrode case 12 is sealed inward to constitute a coin-type battery. By providing the reinforcing rib 17b, the strength of the flange 17a at the peripheral edge of the battery inner case 17 is improved, and the gasket bottom 13a of the gasket 13 can be compressed stably at the time of sealing. It is preferable from the viewpoint of conductivity that the battery case 17 is welded to the positive electrode case 12 at each bottom.

  Here, a plan view from the opening of the battery inner case 17 is shown in FIG. By providing the reinforcing rib 17b, a groove portion 17c on the upper surface side of the flange 17a at the peripheral edge portion of the battery case 17 is generated. Although there is no limitation in the shape of the groove part 17c, providing uniformly over the perimeter is preferable also from improving the stability at the time of sealing.

  The cross section of the battery inner case 17 is divided into the case where the reinforcing rib 17b is included and the case where the reinforcing rib 17b is not included, which are shown in FIGS. 3 and 4, respectively. 3 is a cross-sectional view taken along line AA shown in FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB shown in FIG. Here, the reinforcing rib 17b is provided so as to straddle the side wall from the flange 17a at the peripheral edge of the battery case 17. As a result, the strength of the peripheral ridges 17a is improved, and the stability of the peripheral ridges 17a during sealing can be further increased.

Further, the reinforcing rib 17b forms the reinforcing rib 17b on the side wall portion by expanding the opening portion from the opening portion of the battery inner case 7 to the bottom surface portion by pushing out. When the depth of the groove portion 17c is deep, as shown in FIG. 5, the bottom end top portion of the folded portion 11a of the sealing plate 11 and the flange 17a at the peripheral edge portion of the battery case can uniformly compress the gasket bottom portion 13a of the gasket 13 during sealing. The reliability at the time of sealing is reduced. Therefore, it is preferable that the outermost position of the groove portion 17 c is formed so as to be inside the lower end top portion of the folded portion 11 a of the sealing plate 11.

  On the other hand, in addition to the groove-like structure described above, the thickness can be locally increased to provide an effect as a reinforcing rib. In this case, a half sectional view of the coin-type battery including the thick reinforcing rib 17d is as shown in FIG.

Example 1
A coin-type lithium primary battery having the structure shown in FIG. 1 was produced according to the following procedure.

  By using manganese dioxide as the positive electrode active material, using tetrafluoroethylene resin (PTFE) as the binder, further mixing graphite as the conductive agent, and press-molding the resulting mixture, the pellet-shaped positive electrode 15 Was made. The negative electrode 16 is formed by punching a thin plate-like metal lithium into a disk shape. Further, the separator 14 is made of a polypropylene non-woven fabric and is punched into a circular shape like the negative electrode 16. The electrolyte was prepared by dissolving 0.5 M / l of lithium perchlorate as an electrolyte in a solvent in which 1,2-dimethoxyethane and propylene carbonate were mixed.

  The sealing plate 11 is made of stainless steel and is turned into a bottomed cylindrical shape by folding the periphery, and the positive electrode case 12 is pressed into a bottomed cylindrical shape using stainless steel. The battery inner case 17 is made of stainless steel and is pressed into a shape in which peripheral edges 17a and reinforcing ribs 17b are provided. Here, as shown in FIG. 1, the outermost position of the groove portion 17 c on the upper surface side of the flange 17 a at the peripheral edge portion formed by the reinforcing rib 17 b is inside the lower end top portion of the folded portion 11 a of the sealing plate 11. Has been processed.

  On the other hand, the gasket 13 that forms the battery container together with these was formed by annularly injection-molding polyphenylene sulfide resin. A sealant mainly composed of asphalt was applied to the contact surface between the sealing plate 11 and the gasket 13, the contact surface between the positive electrode case 12 and the gasket 13, and the contact surface between the battery case 17 and the gasket 13.

  A positive electrode 15 and a negative electrode 16 are arranged opposite to each other with a separator 14 therebetween, filled with an electrolyte solution, a sealing plate 11 is arranged in an opening of the positive electrode case 12 via a gasket 13, and a peripheral edge of the battery case 17 Reinforcing ribs 17b are provided in the lower part of the flanges 17a of the part, and the upper end of the opening of the positive electrode case 12 is bent inward to form a coin-type battery. A coin-type lithium primary battery having this configuration was manufactured and designated as battery A. Battery A has a diameter of 24 mm and a height of 7.7 mm.

(Example 2)
A battery produced in the same manner as battery A was designated as battery B, except that reinforcing ribs 17d having locally increased thickness were formed on the lower and side walls of the flange 17a at the peripheral edge of the battery inner case.

(Comparative Example 1)
A battery C was prepared in the same manner as the battery A except that the battery inner case 17 was not provided with a reinforcing rib.

(Example 3)
The outermost position of the groove 17c on the upper surface of the flange 17a at the peripheral edge of the battery inner case 17 is the sealing plate 11.
A battery produced in the same manner as the battery A was designated as battery D, except that it was processed outside the lower end top of the folded portion 11a.

  As a characteristic evaluation of these batteries, a thermal shock test was performed at −10 ° C. for 1 hour / 60 ° C. for 1 hour, that is, 1 cycle for 2 hours, and the number of leaked liquids was confirmed visually. (Table 1) shows the results of leakage resistance characteristics in the thermal shock test.

  When battery A to battery D were compared, as apparent from (Table 1), battery A and battery B did not leak even after 500 cycles of the thermal shock test. This is because the reinforcing ribs 17b are applied to the battery inner case 17 so that the flange 13a at the peripheral edge of the battery inner case 17 is not deformed even after sealing and after the thermal shock test, and the gasket 13 is compressed without variation. It is.

  On the other hand, the battery inner case 17 does not have the reinforcing rib 17b, and the battery inner case 17 has the reinforcing rib 17b. However, the outermost position of the groove portion 17c on the upper surface side of the peripheral flange 17a is the folded portion of the sealing plate 11. In both batteries D on the outside of the lower end top portion of 11a, leakage occurred after 500 cycles of the thermal shock test.

  When the batteries after the thermal shock test evaluation are disassembled and the internal structure is confirmed, the battery C has a flange 17a at the peripheral edge of the battery inner case 17 deformed downward due to the sealing force, and the gasket 13 is appropriately compressed. In addition, since the battery D is provided with the reinforcing ribs 17b on the battery inner case 17, deformation of the peripheral edge 17a of the battery inner case 17 is not seen, but the peripheral edge 17a of the battery inner case 17 is not observed. Since the outermost position of the groove portion 17c on the upper surface side is outside the top of the lower end of the folded portion 11a of the sealing plate 11, the gasket bottom portion 13a and the flange 17a at the peripheral portion of the battery case 17 are not in close contact with each other during sealing. This is thought to be due to a decrease in leakage resistance.

  Even in the case of batteries having different diameters and heights, as described above, the reinforcing ribs 17b and the thick reinforcing ribs 17d are provided below the flanges 17a at the peripheral edge of the battery inner case 17, thereby stabilizing the sealing and preventing leakage. A coin-type lithium battery having excellent liquid properties could be provided.

  The present invention is particularly useful in the design of a battery having a high battery height, for example, a height of 3.0 mm or more, and prevents deformation of the heel by applying pressure at the time of sealing at the lower part of the rim of the battery inner case. By providing the reinforcing ribs, it is possible to provide a coin-type battery that prevents the peripheral edge of the battery inner case from being deformed at the time of sealing, stabilizes the sealing, and has excellent leakage resistance.

DESCRIPTION OF SYMBOLS 11 Sealing plate 11a Folding part 12 Positive electrode case 13 Gasket 13a Gasket bottom part 14 Separator 15 Positive electrode 16 Negative electrode 17 Battery inner case 17a Perimeter edge 17b Reinforcement rib 17c Groove part 17d Thickness reinforcement rib

Claims (4)

In a coin-type battery including a battery inner case, a positive electrode, a separator, a negative electrode, and an electrolyte solution having a rim at the periphery, and sealed by a positive electrode case and a sealing plate via a gasket disposed on the rim of the battery inner case A coin-type battery comprising a reinforcing rib for preventing deformation of the bag by a pressure applied at the time of sealing at a lower part of the bag at the peripheral edge of the battery inner case. 2. The coin-type battery according to claim 1, wherein the reinforcing rib has a groove shape formed on a ridge of the battery inner case and a side wall of the battery inner case. In the groove-shaped reinforcing rib formed on the wall of the battery inner case and the side wall of the battery inner case, the outermost position of the groove of the battery inner case is formed to be inside the lower end top of the folded portion of the sealing plate. The coin-type battery according to claim 2, wherein The coin-type battery according to claim 1, wherein a thickness of the reinforcing rib is thicker than a plate thickness of the battery inner case.