JP6045830B2 - Flat battery - Google Patents

Description

  The present invention relates to a flat battery such as a coin battery.

  Conventionally, a flat battery including a bottomed cylindrical outer can and a sealing can disposed so as to cover the opening of the outer can is known. In such a flat battery, for example, as disclosed in Patent Documents 1 and 2, in order to maintain airtightness inside the battery and to ensure electrical insulation between the outer can and the sealing can, A resin gasket is arranged at the connection with the can. That is, a gasket sandwiched between the outer can and the outer can is disposed on the peripheral wall portion of the sealed can.

  Patent Documents 1 and 2 disclose a configuration in which the gasket is molded on the peripheral wall portion of the sealing can.

JP-A-4-34837 JP-A 61-233965

  By the way, like the above-mentioned each structure, when molding a gasket on the peripheral wall portion of the sealing can, injection molding in which a molten resin material is injected into a molding die is used. That is, in the state where the opening end side of the peripheral wall portion of the sealing can is disposed in the mold, the molten resin material is injected into the mold. At this time, the molten resin material is injected into the mold at a predetermined pressure so that the melted resin material is distributed in the mold.

  In general, since the thickness of the peripheral wall of the sealing can of a flat battery is thin, when the resin material injected at a predetermined pressure hits the peripheral wall of the sealing can during the above-described injection molding, the peripheral wall can be deformed. There is sex.

  In addition, when the resin material melted in the injection molding hits the peripheral wall portion of the sealing can, the peripheral wall portion of the sealing can prevents the resin material from entering the molding die. It becomes difficult to spread.

  An object of the present invention is to provide a flat battery in which a gasket is molded on a peripheral wall portion of a sealing can, while preventing the deformation of the peripheral wall portion of the sealing can at the time of injection molding of the gasket, and a resin material in the mold. The object is to obtain a configuration that allows efficient injection.

  A flat battery according to an embodiment of the present invention includes a bottomed cylindrical outer can having a cylindrical side wall portion extending in a cylindrical axis direction, and a peripheral wall portion extending in the cylindrical axis direction. A bottomed cylindrical sealing can that covers the opening of the outer can so as to be positioned inside the outer can, and formed by injection molding on a peripheral wall portion of the sealing can and sandwiched between the outer can and the sealing can A gasket formed on the peripheral wall portion so as to cover at least a part of the peripheral wall portion of the sealing can, and the gasket is formed integrally with the cover portion, with respect to the peripheral wall portion. And a projecting portion positioned outward in the cylinder axis direction, the projecting portion having an injection portion formed corresponding to an injection port of a molding die used for injection molding of the gasket (first Constitution).

  Thereby, when molding a gasket on the peripheral wall portion of the sealing can, it is possible to prevent the peripheral wall portion of the sealing can from being deformed by the resin material injected into the mold. In other words, the injection portion corresponding to the injection port of the mold is provided in the protruding portion located on the outer side in the cylinder axis direction with respect to the peripheral wall portion of the sealing can in the gasket. Therefore, at the time of injection molding, the resin material is injected into a portion where the peripheral wall portion of the sealing can does not exist. Therefore, when the resin material is injected into the mold, it can be prevented that the resin material directly hits the peripheral wall portion of the sealing can. Thereby, it can prevent that the surrounding wall part of a sealing can produces a deformation | transformation with the resin material injected in the shaping | molding die at the time of injection molding. Moreover, since the resin material injected into the mold does not directly hit the peripheral wall portion of the sealing can during injection molding, it is possible to prevent the flow of the resin material from being obstructed by the peripheral wall portion. Therefore, the resin material can be efficiently injected into the mold.

  In the first configuration, the covering portion and the projecting portion are sandwiched between the cylindrical side wall portion of the outer can and the peripheral wall portion of the sealing can, and the portion positioned on the outer can side. It is preferable that the portion is located in a portion of the protruding portion that faces the cylindrical side wall portion of the outer can (second configuration).

  Thereby, it can prevent more reliably that the resin material inject | emitted in a shaping | molding die hits the surrounding wall part of a sealing can. That is, when the molten resin material is injected into the molding die from the portion of the gasket protruding portion located on the outer can side, the resin material is injected into the portion where the peripheral wall portion of the sealing can does not exist in the molding die. The Therefore, it is possible to more reliably prevent the peripheral wall portion of the sealing can from being deformed by the resin material injected into the mold during injection molding, and it is possible to inject the resin material more efficiently into the mold.

  In the second configuration, it is preferable that the injection portion has a recess formed on the surface of the protruding portion (third configuration). By carrying out like this, the recessed part formed in the injection | pouring part forms a clearance gap between an exterior can and a gasket in the state where the gasket was pinched | interposed between the sealing can and the exterior can. Thereby, even when the electrolytic solution or the like in the flat battery enters between the gasket and the outer can, the electrolytic solution or the like can be stored in the gap formed by the recess. Therefore, the above-described configuration can prevent liquid leakage of the flat battery.

  In any one of the first to third configurations, it is preferable that the protruding portion has a length in the cylindrical axis direction larger than a dimension in the thickness direction of the protruding portion (fourth configuration). ).

  Thus, in the case of a configuration in which the dimension of the protruding portion in the cylinder axis direction is large, it is easy to provide the injection portion of the resin material in a portion of the protruding portion facing the cylindrical side wall portion of the outer can.

  Moreover, the protrusion part which has the above structure tends to produce a deformation | transformation in the said cylinder axis direction. Therefore, the tip portion of the protrusion is deformed inward of the gasket, and a gap is formed between the protrusion and the outer can. The gap between the gasket and the outer can can be stored in the gap. Therefore, the liquid leakage of the flat battery can be prevented more reliably.

  In the method for manufacturing a flat battery according to an embodiment of the present invention, a sealing can forming step of forming a bottomed cylindrical sealing can, and a molding die on the peripheral wall portion of the sealing can, the sealing can A gasket forming step of injection-molding a gasket having a covering portion that covers the peripheral wall portion and a protruding portion that protrudes from the covering portion. The gasket is formed by injecting resin to the part to be formed (fifth method).

  By this method, it is possible to prevent the peripheral wall portion of the sealing can from being bent by the injected resin material during injection molding, and the flow of the resin material in the mold from being inhibited by the peripheral wall portion. Therefore, the resin material can be efficiently injected into the mold while preventing the peripheral wall portion of the sealing can from being deformed during the injection molding.

  In the flat battery according to an embodiment of the present invention, when the gasket is injection-molded, the protruding portion protruding from the covering portion covering the peripheral wall portion of the sealing can among the gaskets sandwiched between the outer can and the sealing can. Inject the resin material. Thus, the resin material can be efficiently injected into the mold while preventing the peripheral wall portion of the sealing can from being deformed during injection molding.

FIG. 1 is a cross-sectional view showing a schematic configuration of a flat battery according to an embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view showing the structure of the electrode body in the flat battery in an enlarged view. FIG. 3 is a partially enlarged cross-sectional view showing an enlarged injection portion of the gasket. FIG. 4 is a view showing a state when a gasket is molded on the negative electrode can.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

(overall structure)
FIG. 1 is a cross-sectional view showing a schematic configuration of a flat battery 1 according to an embodiment of the present invention. The flat battery 1 is sandwiched between a positive electrode can 10 as a bottomed cylindrical outer can, a negative electrode can 20 as a sealing can covering the opening of the positive electrode can 10, and the positive electrode can 10 and the negative electrode can 20. And the electrode body 40 housed in a space formed between the positive electrode can 10 and the negative electrode can 20. Therefore, the flat battery 1 is formed into a flat coin shape by combining the positive electrode can 10 and the negative electrode can 20 together. In the space formed between the positive electrode can 10 and the negative electrode can 20 of the flat battery 1, in addition to the electrode body 40, a non-aqueous electrolyte (not shown) is also enclosed. The battery case is configured by combining the positive electrode can 10 and the negative electrode can 20.

  The positive electrode can 10 is made of a metal material such as stainless steel, and is formed into a bottomed cylindrical shape by press molding. The positive electrode can 10 includes a circular bottom portion 11 and a cylindrical peripheral wall portion 12 (cylindrical side wall portion) formed continuously with the bottom portion 11 on the outer periphery thereof. The peripheral wall portion 12 is provided so as to extend substantially vertically from the outer peripheral end of the bottom portion 11 in a longitudinal sectional view (the state illustrated in FIG. 1). As will be described later, the positive electrode can 10 is crimped to the negative electrode can 20 by folding the opening end side of the peripheral wall portion 12 inside the positive electrode can 10 with the gasket 30 sandwiched between the positive electrode can 20 and the negative electrode can 20. It has been. Note that the symbol P in FIG. 1 is the cylinder axis of the positive electrode can 10. The peripheral wall portion 12 extends in the cylinder axis direction of the positive electrode can 10.

  Similarly to the positive electrode can 10, the negative electrode can 20 is made of a metal material such as stainless steel and is formed in a bottomed cylindrical shape by press molding. The negative electrode can 20 has a substantially cylindrical peripheral wall portion 22 whose outer shape is smaller than that of the peripheral wall portion 12 of the positive electrode can 10, and a circular plane portion 21 that closes one of the openings. Similar to the positive electrode can 10, the peripheral wall portion 22 is also provided so as to extend substantially perpendicular to the flat portion 21 in a longitudinal sectional view. The peripheral wall portion 22 is formed with an enlarged diameter portion 22b whose diameter is increased stepwise compared to the base end portion 22a on the flat surface portion 21 side. That is, the peripheral wall portion 22 is formed with a step portion 22c between the base end portion 22a and the enlarged diameter portion 22b. As shown in FIG. 1, the open end side of the peripheral wall portion 12 of the positive electrode can 10 is bent and caulked with respect to the step portion 22c. That is, the positive electrode can 10 has the opening end side of the peripheral wall portion 12 fitted to the step portion 22 c of the negative electrode can 20. The peripheral wall portion 22 of the negative electrode can 20 also extends in the cylinder axis direction, like the peripheral wall portion 12 of the positive electrode can 10.

  The gasket 30 is made of polypropylene (PP). The gasket 30 is molded on the peripheral wall portion 22 of the negative electrode can 20 so as to be sandwiched between the peripheral wall portion 12 of the positive electrode can 10 and the peripheral wall portion 22 of the negative electrode can 20. The detailed configuration of the gasket 30 will be described later. The material of the gasket 30 is not limited to PP, and a resin composition containing an olefin elastomer in polyphenylene sulfide (PPS), polytetrafluoroethylene (PFA), a polyamide resin, or the like may be used.

  As shown in FIG. 2, the electrode body 40 is formed by laminating a plurality of substantially disc-like positive electrodes 41 and substantially disc-like negative electrodes 46 accommodated in a bag-like separator 44 in the thickness direction. Do it. Thereby, the electrode body 40 has a substantially cylindrical shape as a whole. In addition, the electrode body 40 has a plurality of positive electrodes 41 and negative electrodes 46 stacked so that both end faces are negative electrodes.

  The positive electrode 41 is obtained by arranging positive electrode active material layers 42 containing a positive electrode active material such as lithium cobaltate on both surfaces of a positive electrode current collector 43 made of a metal foil such as aluminum.

  The negative electrode 46 is configured by disposing negative electrode active material layers 47 containing a negative electrode active material such as graphite on both surfaces of a negative electrode current collector 48 made of a metal foil such as copper. The negative electrodes located at both ends in the axial direction of the substantially cylindrical electrode body 40 are arranged on one surface side of the negative electrode current collector 48 so that the negative electrode current collectors 48 are located at the axial ends of the electrode body 40, respectively. Only the negative electrode active material layer 47 is provided. That is, the negative electrode current collectors 48 are exposed at both ends of the substantially cylindrical electrode body 40. One negative electrode current collector 48 of the electrode body 40 is positioned on the bottom portion 11 of the positive electrode can 10 via the positive electrode current collector 43 and the insulating sheet 49 (see FIGS. 1 and 2). The other negative electrode current collector 48 of the electrode body 40 abuts on the flat portion 21 of the negative electrode can 20 in a state where the electrode body 40 is disposed between the positive electrode can 10 and the negative electrode can 20 (see FIG. 1). .

  The separator 44 is a bag-shaped member formed in a substantially circular shape in plan view, and is formed in a size that can accommodate the substantially disk-shaped positive electrode 41. The separator 44 is constituted by a microporous thin film made of polyethylene having excellent insulating properties. Thus, by forming the separator 44 with a microporous thin film, lithium ions can pass through the separator 44. The separator 44 is formed by wrapping the positive electrode 41 with a single sheet of a rectangular microporous thin film and bonding the overlapping portions of the sheet material by thermal welding or the like.

  As shown in FIGS. 1 and 2, the positive electrode current collector 43 of the positive electrode 41 is integrally formed with a conductive positive electrode lead 51 extending outward from the positive electrode current collector 43 in a plan view. The positive electrode current collector 43 side of the positive electrode lead 51 is also covered with the separator 44. A positive electrode current collector 43 that is not provided with the positive electrode active material layer 42 is disposed between the insulating sheet 49 and the bottom 11 of the positive electrode can 10. That is, the positive electrode current collector 43 is in electrical contact with the bottom 11 of the positive electrode can 10.

  The negative electrode current collector 48 of the negative electrode 46 is integrally formed with a conductive negative electrode lead 52 extending outward from the negative electrode current collector 48 in plan view.

  As shown in FIGS. 1 and 2, the positive electrode 41 and the negative electrode 46 are such that the positive electrode lead 51 of each positive electrode 41 is located on one side and the negative electrode lead 52 of each negative electrode 46 is on the opposite side of the positive electrode lead 51. Laminated so as to be positioned.

  As described above, with the plurality of positive electrodes 41 and the negative electrodes 46 laminated in the thickness direction, the plurality of positive electrode leads 51 are overlapped with each other in the thickness direction and connected by ultrasonic welding or the like. Accordingly, the plurality of positive electrodes 41 are electrically connected to each other via the plurality of positive electrode leads 51, and each positive electrode 41 and the positive electrode can 10 are electrically connected to each other. On the other hand, the plurality of negative electrode leads 52 are also connected to each other by ultrasonic welding or the like with the distal end side overlapped in the thickness direction. Accordingly, the plurality of negative electrodes 46 are electrically connected to each other via the plurality of negative electrode leads 52, and each negative electrode 46 and the negative electrode can 20 are electrically connected to each other.

(Gasket configuration)
Next, the structure of the gasket 30 is demonstrated in detail using FIG.1, FIG3 and FIG.4.

  As shown in FIGS. 1 and 4, the gasket 30 is formed in a substantially cylindrical shape so as to wrap around the peripheral wall portion 22 of the negative electrode can 20. Specifically, the gasket 30 is molded on the negative electrode can 20 so as to cover the inner side of the negative electrode can of the peripheral wall portion 22 and the outer side of the negative electrode can of the step portion 22c and the enlarged diameter portion 22b of the peripheral wall portion 22. Molded. The gasket 30 is provided so as to protrude from the opening side of the peripheral wall portion 22 in the cylinder axis direction of the negative electrode can 20. That is, the gasket 30 includes a covering portion 31 that covers the peripheral wall portion 22 of the negative electrode can 20, and a protruding portion 32 that is located on the outer side in the cylinder axis direction of the negative electrode can 20 with respect to the peripheral wall portion 22 of the negative electrode can 20.

  As shown in FIG. 1, the gasket 30 has an inner diameter that is substantially flush with the inner surface of the base end portion 22 a of the peripheral wall portion 22 of the negative electrode can 20. That is, the covering portion 31 and the protruding portion 32 of the gasket 30 have the same inner diameter.

  The gasket 30 has such a length as to contact the bottom portion 11 of the positive electrode can 10 in a state where the peripheral wall portion 12 of the positive electrode can 10 is caulked on the outer peripheral side of the negative electrode can 20. Thereby, when the positive electrode can 10 is caulked against the negative electrode can 20, the tip portion of the protrusion 32 of the gasket 30 is pressed against the bottom 11 of the positive electrode can 10. Thereby, the space formed by the positive electrode can 10 and the negative electrode can 20 is sealed by the tip portion of the protruding portion 32 of the gasket 30.

  Further, as described above, the gasket 30 is compressed by the open end side of the peripheral wall portion 12 of the positive electrode can 10 by caulking the open end side of the peripheral wall portion 12 of the positive electrode can 10 to the outer peripheral side of the negative electrode can 20. The Therefore, the gasket 30 seals between the peripheral wall portion 12 of the positive electrode can 10 and the outer peripheral side of the negative electrode can 20.

  The pressing force of the tip end portion of the protruding portion 32 of the gasket 30 against the bottom portion 11 of the positive electrode can 10 is the force that the gasket 30 receives when the outer peripheral side of the peripheral wall portion 12 of the positive electrode can 10 is caulked to the outer peripheral side of the negative electrode can 20. Is obtained.

  The protruding portion 32 of the gasket 30 has a length in the cylinder axis direction of the negative electrode can 20 equivalent to the length in the cylinder axis direction of the covering portion 31 that covers the peripheral wall portion 22 of the negative electrode can 20. Further, the protruding portion 32 of the gasket 30 has a length in the cylindrical axis direction larger than a dimension in the thickness direction corresponding to the radial direction of the negative electrode can 20.

  As described above, the protrusion 32 that does not cover the peripheral wall portion 22 of the negative electrode can 20 in the gasket 30 has a long shape in the cylinder axis direction of the negative electrode can 20, so that the protrusion 32 can be easily deformed. it can.

  In addition, since the length of the entire gasket 30 in the cylinder axis direction is larger than that in the conventional case, the positive electrode can 10 and the negative electrode can 20 can be sealed by the gasket 30 in a wide range. Thereby, it can prevent more reliably that a liquid leak etc. arise from the clearance gap between the positive electrode can 10 and the negative electrode can 20. FIG.

  As will be described later, the gasket 30 of the present embodiment is formed by so-called injection molding in which a molten resin material is injected into a mold and molded. An injection portion 33 is located on the protrusion 32 of the gasket 30 corresponding to an injection port for injecting a molten resin material into the mold. That is, the injection part 33 is formed by an injection port for injecting a resin material into the mold when the gasket 30 is injection-molded.

  The injection part 33 has a concave part 33a formed when the convex part 30a (see FIG. 4) formed by the injection port is removed. That is, as will be described later, a protrusion 30a from which resin protrudes is formed on the protrusion 32 of the gasket 30 by the injection port of the mold. The convex portion 30a is removed by a part of the molding die when the gasket 30 is taken out from the molding die. Therefore, the root portion of the convex portion 30a is removed, and the concave portion 33a as described above is formed.

  Thus, by injecting the resin material to the portion where the protrusion 32 of the gasket 30 is formed, the peripheral wall portion 22 of the negative electrode can 20 is prevented from being deformed by the resin material injected into the mold. it can. Further, with the above-described configuration, it is possible to prevent the peripheral wall portion 22 of the negative electrode can 20 from hindering the injection of the resin material into the mold.

  Furthermore, since the injection part 33 has the recessed part 33a formed in the surface at the side of the positive electrode can 10 of the protrusion part 32, as shown in FIG.1 and FIG.3, the state which crimped the positive electrode can 10 with respect to the negative electrode can 20 Thus, a gap 35 is formed between the peripheral wall portion 12 of the positive electrode can 10 and the gasket 30. In the gap 35, the electrolytic solution or the like that has entered between the protruding portion 32 of the gasket 30 and the bottom portion 11 of the positive electrode can 10 is accumulated. Therefore, the gap 35 can prevent leakage of the electrolyte solution or the like in the flat battery 1.

  As described above, the protrusion 32 of the gasket 30 has a length corresponding to the cylinder axis direction of the negative electrode can 20 larger than the dimension in the thickness direction. Thereby, in the molding die of the gasket 30, an injection port for injecting the resin material can be easily provided in a portion forming the peripheral wall portion 12 side of the protruding portion 32.

(Manufacturing method of flat battery)
Next, a method for manufacturing the flat battery 1 having the above-described configuration will be described.

  First, the bottomed cylindrical positive electrode can 10 and negative electrode can 20 are each formed by press molding.

  On the other hand, a plurality of plate-like positive electrodes 41 covered with a separator 44 and a plurality of plate-like negative electrodes 46 are laminated in the thickness direction to form a substantially cylindrical electrode body 40 as shown in FIG. Since the electrode body 40 is manufactured by a method similar to the conventional method, the detailed manufacturing method will not be described.

  The manner in which the gasket 30 is molded on the negative electrode can 20 will be described with reference to FIG.

  As shown in FIG. 4, a fixed mold 61, a movable mold 62, and a piston movable mold 63 having a ring-shaped cross section are arranged outside the negative electrode can 20, and pins 64 are arranged inside the negative electrode can 20. To place. Accordingly, a space 60 for forming the gasket 30 is formed around the peripheral wall portion 22 of the negative electrode can 20 by the molds 61, 62, 63 and the pins 64. Accordingly, the fixed mold 61, the movable mold 62, the piston movable mold 63, and the pin 64 constitute a mold for molding the gasket 30.

  The fixed mold 61 is provided with an inlet 61 a for injecting a resin material from the outside into the space 60. By injecting a molten resin material into the space 60 from the injection port 61a, the space 60 is filled with the resin material. At this time, since the injection port 61a of the fixed mold 61 is provided at a position where the peripheral wall portion 22 of the negative electrode can 20 does not exist, when the resin material is injected from the injection port 61a, it hits the peripheral wall portion 22 and the peripheral wall portion. It is possible to prevent the deformation of 22. In addition, the peripheral wall portion 22 can prevent the flow of the resin material from being hindered.

  After the resin material in the space 60 is cured and the gasket 30 is molded, first, the movable mold 62 is removed. Then, the negative electrode can 20 in which the gasket 30 is molded is removed from the pin 64 and the fixed mold 61 by moving the piston movable mold 63 in the axial direction of the pin 64 (the direction of the white arrow in FIG. 4). Can be separated.

  As shown in FIG. 4, the gasket 30 has a protrusion 30 a that protrudes into the injection port 61 a of the fixed mold 61 in a state where the gasket 30 is molded with a resin material in the space 60. The convex portion 30 a is cut by the fixed mold 61 when the gasket 30 is moved in the direction of the white arrow in FIG. 4 with respect to the fixed mold 61 as described above. At this time, since the gasket 30 made of a resin material such as PP is removed so that only the projecting portion 30a is not cut away cleanly, it is removed on the surface of the gasket 30 as shown in FIGS. A concave portion 33a is formed.

  Here, the fixed mold 61 is formed in a taper shape such that the portion that molds the outer surface of the cylindrical gasket 30 gradually increases in inner diameter toward the step portion 22 c of the peripheral wall portion 22 of the negative electrode can 20. ing. Thereby, when the gasket 30 is pushed by the piston movable mold 63 as described above, the negative electrode can 20 can be easily detached from the fixed mold 61.

In the positive electrode can 10, the electrode body 40 is disposed together with the insulating sheet 47 and the like, and a non-aqueous electrolyte is injected. Then, the negative electrode can 20 in which the gasket 30 is molded as described above is disposed so as to cover the opening of the positive electrode can 10. In this state, the opening end side of the peripheral wall portion 12 of the positive electrode can 10 is bent and crimped inward of the positive electrode can 10 with respect to the step portion 22 c of the peripheral wall portion 22 of the negative electrode can 20. Thereby, the flat battery 1 of the above-mentioned structure is obtained. Here, the nonaqueous electrolytic solution can be obtained, for example, by dissolving LiPF ₆ in a solvent obtained by mixing ethylene carbonate and methyl ethyl carbonate.

  Here, the step of forming the negative electrode can 20 by press molding corresponds to the sealing can forming step, and the step of molding the gasket 30 on the peripheral wall portion 22 of the negative electrode can 20 corresponds to the gasket forming step.

(Effect of embodiment)
In this embodiment, the gasket 30 formed on the peripheral wall portion 22 of the negative electrode can 20 includes a covering portion 31 that covers the peripheral wall portion 22 and a protruding portion 32 that protrudes from the covering portion 31 in the cylindrical axis direction of the negative electrode can 20. And have. The protrusion 32 has an injection portion 33 corresponding to an injection port for injecting a resin material into the mold when the gasket 30 is formed by injection molding.

  Thereby, when the gasket 30 is injection-molded, the peripheral wall portion 22 of the negative electrode can 20 is deformed by the resin material injected into the mold, or the resin material flows in the mold by the peripheral wall portion 22. It can be prevented from being disturbed. Therefore, the structure which can inject | pour resin material efficiently in a shaping | molding die at the time of injection molding is obtained, preventing the deformation | transformation of the surrounding wall part 22 of the negative electrode can 20 at the time of carrying out injection molding of the gasket 30.

  Further, the injection portion 33 formed in the gasket 30 has a concave portion 33 a obtained by cutting the convex portion 30 a formed in the injection port of the molding die with the fixed molding die 61. Thereby, a gap 35 is formed in the injection portion 33 of the gasket 30 between the gasket 30 and the peripheral wall portion 12 of the positive electrode can 10. By forming the gap 35, even when the electrolytic solution or the like in the flat battery 1 enters between the gasket 30 and the peripheral wall portion 12 of the positive electrode can 10, the electrolytic solution or the like is held in the gap 35. Is possible. Therefore, the liquid leakage of the flat battery 1 can be prevented by the concave portion 33a of the injection portion 33.

  Moreover, the length of the protruding portion 32 of the gasket 30 in the cylinder axis direction of the negative electrode can 20 is larger than the dimension in the thickness direction. Therefore, when the peripheral wall portion 12 of the positive electrode can 10 is caulked against the peripheral wall portion 22 of the negative electrode can 20, the gasket 30 is compressed in the cylindrical axis direction, and the tip end side of the projecting portion 32 falls to the inside of the gasket 30. Deforms like As a result, a gap is partially formed between the gasket 30 and the positive electrode can 10. This gap also makes it possible to prevent liquid leakage from the flat battery 1.

(Other embodiments)
Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

  In the embodiment, the protruding portion 32 of the gasket 30 has the same length in the cylinder axis direction of the negative electrode can 20 as the length of the covering portion 31 of the gasket 30 in the cylinder axis direction. Moreover, in the said embodiment, the protrusion part 32 has the said length of the said cylinder axis direction larger than the dimension of the thickness direction. However, the protrusion 32 may have any size as long as the resin can be injected into the mold during injection molding, that is, the protrusion 33 can be formed with the recess 33a. Good.

  In the said embodiment, although the electrode body 40 is set as the structure which laminated | stacked the some positive electrode 41 and the negative electrode 46 alternately, the structure of an electrode body may be other than this.

  In the embodiment, the positive electrode can 10 is an outer can and the negative electrode can 20 is a sealed can. Conversely, the positive electrode can may be a sealed can and the negative electrode can may be an outer can.

  In the embodiment, the positive electrode can 10 and the negative electrode can 20 are each formed in a bottomed cylindrical shape, and the flat battery 1 is formed in a coin shape. However, the flat battery is not limited thereto, and the flat battery 1 You may form in shapes other than column shape.

  The flat battery according to the present invention can be used for a flat battery in which a gasket is formed into a sealed can.

1: flat battery, 10: positive electrode can (exterior can), 12: peripheral wall (cylindrical side wall), 20: negative electrode can (sealing can), 22: peripheral wall, 30: gasket, 31: covering part, 32 : Protruding part, 33: Injection part, 33a: Recess, 61: Fixed mold, 61a: Injection port, 62: Movable mold, 63: Piston movable mold, 64: Pin

Claims (3)

A bottomed cylindrical outer can having a cylindrical side wall extending in the cylinder axis direction;
A bottomed cylindrical sealing can that covers the opening of the outer can so as to have a peripheral wall portion extending in the cylindrical axis direction, and the peripheral wall portion is positioned inside the outer can;
Formed by injection molding on the peripheral wall portion of the sealing can, and provided with a gasket sandwiched between the exterior can and the sealing can,
The gasket is
A covering portion formed on the peripheral wall portion so as to cover at least a part of the peripheral wall portion of the sealing can;
A protrusion formed integrally with the covering portion and positioned outward in the cylinder axis direction with respect to the peripheral wall portion;
The covering portion and the protruding portion are sandwiched between a cylindrical side wall portion of the outer can and a peripheral wall portion of the sealing can, the portion located on the outer can side.
The protrusions may have a injection portion formed corresponding to the mold inlet to be used for injection molding of the gasket,
The injection part is located in a portion of the protrusion that faces the cylindrical side wall of the outer can,
The injection portion has a recess formed on the surface of the protrusion.
Flat battery. The flat battery according to claim 1,
The protruding portion is a flat battery in which a length in the cylinder axis direction is larger than a dimension in a thickness direction of the protruding portion. A sealing can forming step of forming a bottomed cylindrical sealing can;
On the peripheral wall portion of the sealing can, using a molding die, a gasket forming step of injection-molding a gasket having a covering portion covering the peripheral wall portion of the sealing can and a protruding portion protruding from the covering portion,
In the gasket molding step, a flat battery manufacturing method in which the gasket is molded by injecting a resin to a portion of the mold that forms the protruding portion during injection molding.

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