JP4748999B2 - Cylindrical battery sealing method - Google Patents

Description

  The present invention relates to a cylindrical battery sealing method in which an opening of a bottomed cylindrical battery case containing a power generation element is sealed with a sealing plate, and a cylindrical battery formed using the sealing method.

  A cylindrical battery accommodates a power generation element in a bottomed cylindrical battery case, and the opening of the battery case is formed by crimping the opening end of the battery case on the periphery of the sealing plate disposed in the opening of the battery case. Many sealing methods are used. FIG. 4 shows an example of a battery in which the opening of the battery case is sealed by the caulking process, and is configured as an alkaline dry battery (LR20 type).

  In FIG. 4, a battery case 2 having a bottomed cylindrical shape and having a protruding portion at the bottom center accommodates a power generation element composed of a positive electrode mixture 3 and a gel negative electrode 5 via a separator 4. In addition, the peripheral edge portion of the assembly sealing plate composed of the negative electrode current collector 6, the gasket 7, and the sealing plate 8 is sealed by caulking that bends the opening end portion 11 of the battery case 2 inward. An insulating ring 9 is disposed on a portion that has been crimped after the sealing, and the label exterior 1 is applied by exposing the protruding portion of the battery case 2 and the central portion of the sealing plate 8. In this battery, the battery case 2 is an alkaline battery having a protruding portion on the bottom surface as a positive electrode terminal and a sealing plate 8 as a negative electrode terminal.

  The sealing method by caulking is not only applied to the dry battery as described above, but is often applied to sealing of cylindrical batteries regardless of primary batteries and secondary batteries, and many proposals have been made as conventional techniques (for example, , See Patent Document 1).

  FIG. 5 shows a procedure of a cylindrical battery sealing method according to the prior art. As shown in FIG. 5A, a bottomed cylindrical battery case 31 containing a power generation element 30 is guided from its opening. Inserting the support 33 and rotating the battery case 31, the grooved roller 32 is pressed against the outer peripheral surface on the opening side of the battery case 31 to form a support annular groove 34 having a predetermined depth on the outer peripheral surface of the battery case 31. To do.

  Since the support annular groove 34 becomes an annular support step protruding on the inner peripheral surface of the battery case 31, a sealing plate 36 is disposed on the support step via a gasket 35, as shown in FIG. As shown in FIG. 4, the battery case 31 is held from the periphery by the support die 37 having a support protrusion fitted into the support annular groove 34, and the preliminary caulking die 38 is lowered from above to open the open end of the battery case 31. Pre-caulking is performed to curve the part inward.

Next, the crimping die 39 is lowered onto the opening end of the battery case 31 subjected to the preliminary crimping process, and the sealing plate 36 is bent so that the opening end of the battery case 31 is bent along the shape of the crimping recess of the crimping die 39. The caulking process is performed to press the side. The gasket 35 interposed between the battery case 31 pressurized by the caulking process and the sealing plate 36 is pressed against the support step portion by the opening end portion of the battery case 31 and the lower support annular groove 34 and compressed. Therefore, the gasket 35 is in close contact with the battery case 31 and the sealing plate 36, and the opening of the battery case 31 can be sealed in a sealed state.
JP 2001-28395 A

  However, in the sealing method according to the above-described prior art, the entire open end of the battery case 31 is pressurized by the caulking die 39, so that the support step formed by the supporting annular groove 34 is strongly supported by the support step. There is a case in which a phenomenon of sliding down from the support protrusion of the mold 37 may occur, and there is a problem in that the finished height dimension of the battery varies.

  Strict dimensional regulation is also shown in JIS for battery dimensions, and at present, dimensional tolerance management and frequent equipment adjustments corresponding to it are necessary, which is a factor that increases the quality control and manufacturing management cost of battery production. It is also.

  An object of the present invention is to provide a cylindrical battery having a small variation in the height dimension of the battery and a sealing method thereof.

First invention for achieving the above object, the opening of the bottomed cylindrical battery case housing a power generating element Te sealing method smell cylindrical batteries for sealing with a sealing plate,
(A) a grooving step of forming an annular groove on the outer peripheral surface of the battery case so as to form a support step projecting annularly toward the inside on the inner peripheral surface of the battery case on the opening side ;
(B) a sealing plate housing step of placing a sealing plate having a peripheral edge wrapped with a gasket on the support step ;
(C) a preliminary caulking step of holding the battery case from the outer peripheral surface by a support mold having a support protrusion fitted into the annular groove, and bending the opening end of the battery case in an arc shape by the preliminary caulking mold ;
(D) A caulking mold that holds the outer peripheral surface of the battery case by a receiving mold having a support protrusion that fits into the annular groove and descends with a predetermined gap between the outer peripheral surface of the receiving mold. When the opening end preliminarily crimped by pressing is pressed onto the peripheral edge of the sealing plate, the sealing shoulder portion, which is the folding position of the opening end portion, is positioned below the gap and between the supporting stepped portion. and a final crimping step of nipping said gasket in
Have
In the final crimping step (d), the gap between the inner peripheral surface of the receiving mold and the crimping mold is 0.05 mm or more and is not more than twice the peripheral surface thickness of the battery case. Features.

  According to the sealing method described above, after the preliminary caulking process of bending the opening end of the battery case from the predetermined height position to the predetermined angle with respect to the sealing plate placed on the support step, the battery case is held on the outer peripheral surface. The caulking mold is lowered onto the battery case with a predetermined gap from the inner peripheral surface of the receiving mold, and the opening end of the battery case bent at a predetermined angle by the preliminary caulking process is bent on the peripheral edge of the sealing plate. Then, the sealing shoulder enters the gap formed by the crimping mold and the receiving mold to release the impact on the supporting projection side applied to the battery case by the crimping mold, and the annular groove slides down from the supporting projection of the receiving mold. Since such a state is suppressed, the sealing with reduced variation in the battery height dimension is performed.

Furthermore, the gap between the inner peripheral surface of the receiving mold and the caulking mold is 0.05 mm or more, and the inner peripheral surface of the receiving mold is set to be not more than twice the peripheral surface thickness of the battery case. It is possible to prevent the shoulder from rising, which is likely to occur when the gap between the die and the crimping mold is increased.

  In addition, it is preferable that the final caulking process is performed by a caulking mold in which the angle of the lower surface contacting the opening end of the battery case is formed at a predetermined taper angle inclined toward the depression angle toward the center of the battery case. When the final caulking process is performed with a caulking die having a taper angle with the pressing surface inclined toward the center, the opening end of the battery case is bent at an angle inclined downward toward the center, and the gasket is Since it compresses effectively, the sealing excellent in sealing property can be implemented.

According to the present invention, in the cylindrical battery in which the sealing plate is arranged in the opening of the bottomed cylindrical battery case and the opening is sealed by caulking, the battery height dimension variation due to caulking is small, and the shoulder portion Can be prevented, and a cylindrical battery with good sealing property can be manufactured.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. This embodiment shows the sealing method in the process which manufactures the cylindrical alkaline dry battery (LR20 type) previously shown in FIG. In addition, the same code | symbol is attached | subjected to the component which is common in a prior art, and the description is abbreviate | omitted.

  FIG. 1 shows a procedure of a method for sealing an alkaline battery according to an embodiment. As shown in FIG. 1A, a cylindrical battery case 2 having a bottom and containing a power generating element (see FIG. 4) 12 configured by arranging a positive electrode mixture 3 and a gel negative electrode 5 through a separator 4. Then, the guide support 33 is inserted from the opening, and the grooved roller 32 is pressed against the outer peripheral surface at a predetermined height near the opening end while rotating the battery case 2 around the axial center. An annular groove 34 is formed. By forming the support annular groove 34, a support step portion 34 a protruding in an annular shape is formed on the inner peripheral surface of the battery case 2.

  Next, after applying a sealing agent to the inner peripheral surface of the battery case 2 extending from the support step 34a to the opening end, that is, a portion where the gasket 7 described later contacts the battery case 2, as shown in FIG. Then, an assembly sealing plate composed of the negative electrode current collector 6, the gasket 7, and the sealing plate 8 is placed on the support step 34 a, and the support protrusion of the support mold 37 is fitted into the support annular groove 34. The battery case 2 is held from the surroundings, the preliminary caulking die 35 is lowered onto the battery case 2 and pressurized, and the opening end of the battery case 2 is predetermined by the processing recess having the curved shape of the auxiliary caulking die 35. The assembly sealing plate is fixed on the support step 34a by bending inward in an arc from the height position. As shown in FIG. 4, the assembly sealing plate is an assembly in which the gasket 7 and the sealing plate 8 are integrally assembled around the negative electrode current collector 6, and the peripheral portion of the gasket 7 is the peripheral portion of the sealing plate 8. Arranged to wrap.

  Next, as shown in FIG. 1 (c), the battery case 2 is held by the receiving mold 13 that has a support protrusion that fits into the support annular groove 34 and holds the outer peripheral surface on the opening side of the battery case 2. The opening end 11 of the battery case 2 that is held from the periphery and preliminarily crimped by the caulking mold 14 that descends with a predetermined gap G between the inner peripheral surface of the receiving mold 13 and the peripheral edge of the assembly sealing plate A final caulking is performed in which the gasket 7 constituting the assembly sealing plate is clamped with the support step 34a. By this final crimping, as shown in FIG. 1 (d), the gasket 7 is compressed and is in close contact with the sealing plate 8 and the battery case 2, so that the opening of the battery case 2 is coupled with the effect of the applied sealing agent. Is sealed in a sealed state.

  In the sealing method, by providing a gap H between the receiving mold 13, the crimping mold 14 and the sealing shoulder 10, the sealing mold 13 and the crimping mold 14 can be sealed without causing interference. The sealing shoulder portion 10 enters the space H formed by the crimping die 14 and the receiving die 13 while obtaining a good rounded shape of the shoulder portion 10, so that the battery case 2 is pressurized by the crimping die 14. Since the impact to the side of the support protrusion added is released, the annular groove 34 is prevented from sliding off from the support protrusion of the receiving mold 13, and a sealing step is performed in which variation in battery height is reduced. Further, the caulking die 14 is pre-caulked and pressurizes the open end 11 of the battery case 2 on the peripheral edge of the assembly sealing plate, so that the gasket 7 is connected to the open end 11 of the battery case 2 and the supporting step. It is compressed between the part 34a and is in close contact with the sealing plate 8 and the battery case 2 to form a highly airtight seal.

  The result of verifying the optimum value of the gap G between the inner peripheral surface of the receiving mold 13 and the crimping mold 14 will be described below.

  Table 1 shows the evaluation results of the sealing performance when the gap G between the receiving mold 13 and the crimping mold 14 is changed stepwise from 0.02 mm to 0.6 mm. The battery to be evaluated is an LR20 type alkaline dry battery configured as shown in FIG. 4 and is 100 for each value of the gap G between the inner peripheral surface of the receiving mold 13 and the crimping mold 14. Each piece was evaluated for the quality of the sealing portion shape and the presence or absence of occurrence of mold fitting defects. In addition, the thickness of the side peripheral surface of the battery case 2 used for the alkaline dry battery made into the evaluation object is 0.25 mm.

表１から分かるように、受け金型１３とカシメ金型１４との間の間隙Ｇが０．５ｍｍ以下であるとき、即ち電池ケースの側周面厚さの２倍以下であるとき、良好な封口状態が得られる。間隙Ｇが０．６ｍｍ以上になると、図２（ｂ）に示すように、封口肩部１０に角が立ち上がる状態が発生し、電池高さ寸法の誤差が大きくなり、図２（ａ）に示すように、封口肩部１０に所定のアール形状が得られなくなる。従って、受け金型１３とカシメ金型１４との間の間隙Ｇは小さくなるほど良好な封口状態が得られることになる。しかし、表１に示すように、間隙Ｇが０．０４ｍｍ以下の小さい値であるとき、受け金型１３とカシメ金型１４とが干渉する金型嵌合の不具合が発生する。この評価結果から得られた間隙Ｇの最適値は、０．０５ｍｍ以上で、電池ケースの側周面厚さの２倍以下ということになる。

As can be seen from Table 1, when the gap G between the receiving mold 13 and the crimping mold 14 is 0.5 mm or less, that is, when the thickness of the side peripheral surface of the battery case is twice or less, it is good. A sealed state is obtained. When the gap G is 0.6 mm or more, as shown in FIG. 2 (b), a state in which corners rise in the sealing shoulder portion 10 occurs, and the error in the battery height dimension increases, as shown in FIG. 2 (a). Thus, a predetermined round shape cannot be obtained in the sealing shoulder 10. Accordingly, the smaller the gap G between the receiving mold 13 and the crimping mold 14 is, the better the sealing state is obtained. However, as shown in Table 1, when the gap G is a small value of 0.04 mm or less, there is a problem of mold fitting in which the receiving mold 13 and the crimping mold 14 interfere with each other. Optimum value of the gap G resulting from the evaluation results, on 0.05mm or more, it comes to more than twice the side peripheral surface thickness of the battery case.

  Table 2 shows the results of evaluating the influence of the folding angle of the open end of the battery case 2 folded on the assembly sealing plate by caulking on the sealing performance. In plastic working such as caulking, even if the opening end 11 of the battery case 2 is bent at a predetermined angle by the caulking die 14, when the pressurization by the caulking die 14 is released, the battery case 2 tries to return to its original state. Since a state of elastic deformation occurs, it is necessary to appropriately set the bending angle corresponding to the material and thickness of the battery case 2, that is, the angle of the pressing surface of the crimping die 14.

表２は、図３（ａ）に示すように、カシメ金型１４の押圧面の角度Ａを、電池１の封口面を水平として俯角方向に０度から２０度まで段階的に設定してカシメ加工したとき、図３（ｂ）に示すように、電池ケース２の開口端の折曲角度Ｂの状態を検証し、その折曲角度Ｂで封口された電池１の封口性を漏液試験により検証したものである。尚、漏液試験は、折曲角度Ｂ毎にそれぞれ２０個のアルカリ乾電池を温度：６０℃、湿度：９０％の環境下で４週間にわたって保存した場合の漏液発生の有無を検証したものである。

As shown in FIG. 3 (a), the angle A of the pressing surface of the crimping die 14 is set stepwise from 0 to 20 degrees in the depression direction with the sealing surface of the battery 1 being horizontal. When processed, as shown in FIG. 3B, the state of the bending angle B of the open end of the battery case 2 is verified, and the sealing performance of the battery 1 sealed at the bending angle B is determined by a leak test. It has been verified. In addition, the liquid leakage test verified the presence or absence of liquid leakage when storing 20 alkaline batteries for each bending angle B in an environment of temperature: 60 ° C. and humidity: 90% for 4 weeks. is there.

  As can be seen from Table 2, the bending angle B cannot be obtained as the angle A of the pressing surface of the crimping die 14, and when the pressing surface angle A of the crimping die 14 is 5 degrees or less, the bending angle B is Due to the elevation angle direction, the sealing performance is not sufficient, so that leakage occurs. On the other hand, when the pressing surface angle A of the crimping die 14 is set to 7 degrees or more, the bending angle B is changed from the horizontal direction to the depression direction, and no leakage occurs at that time. That is, by performing a caulking process in which the bending angle B changes from the horizontal direction to the depression direction, the gasket 7 is properly compressed and is in close contact with the open end of the battery case 2 and the support step 34a, and the open end of the battery case. Since the edge bites into the gasket 7, a good sealing state without leakage can be obtained. Accordingly, the pressing surface angle A of the crimping die 14 for obtaining a good sealing state is preferably provided with a taper in the depression direction toward the center of the battery 1.

  In the embodiment described above, the sealing method of the alkaline dry battery which is an example of the cylindrical battery has been described. However, the application of the sealing method of the present invention is not limited to this, and a gasket is provided at the opening of the cylindrical battery case. The sealing plate can be arranged in the same manner, and the opening end of the battery case can be bent inward to apply the crimping process.

  As described above, according to the present invention, in the cylindrical battery in which the sealing plate is disposed in the opening portion of the bottomed cylindrical battery case and the opening portion is sealed by the caulking process, the variation in the battery height dimension due to the caulking process is achieved. A cylindrical battery having a small size and good sealing properties can be produced. Sealing of cylindrical batteries by caulking is the most frequently applied sealing method regardless of whether it is a primary battery or a secondary battery. Cylindrical batteries manufactured using them are extremely effective.

The process figure which shows the procedure of the sealing method of the cylindrical battery which concerns on embodiment later on. The fragmentary sectional view which shows defect generation | occurrence | production when the clearance gap between a receiving metal mold and a crimping metal mold | die becomes improper. The fragmentary sectional view explaining the relationship between the pressing surface angle of a crimping metal mold | die, and a crimping angle. Sectional drawing which shows the structure of the alkaline dry battery which is an example of a cylindrical battery. The process figure which shows the procedure of the sealing method of the cylindrical battery concerning a prior art later on.

Explanation of symbols

2 Battery Case 6 Negative Current Collector 7 Gasket 8 Sealing Plate 10 Sealing Shoulder 11 Open End 12 Power Generation Element 13 Receiving Mold 14 Caulking Die 34 Supporting Groove 34a Supporting Step

Claims (2)

In a sealing method for a cylindrical battery, in which an opening of a bottomed cylindrical battery case containing a power generation element is sealed by a sealing plate ,
(A) a grooving step of forming an annular groove on the outer peripheral surface of the battery case so as to form a support step projecting annularly toward the inside on the inner peripheral surface of the battery case on the opening side ;
(B) a sealing plate housing step of placing a sealing plate having a peripheral edge wrapped with a gasket on the support step ;
(C) a preliminary caulking step of holding the battery case from the outer peripheral surface by a support mold having a support protrusion fitted into the annular groove, and bending the open end of the battery case inward by the preliminary caulking mold ;
(D) A caulking mold that holds the outer peripheral surface of the battery case by a receiving mold having a support protrusion that fits into the annular groove and descends with a predetermined gap between the outer peripheral surface of the receiving mold. When the opening end preliminarily crimped by pressing is pressed onto the peripheral edge of the sealing plate, the sealing shoulder portion, which is the bending position of the opening end portion, is positioned under the gap and between the support step portion. and a final crimping step of nipping said gasket in
Have
In the final crimping step (d), the gap between the inner peripheral surface of the receiving mold and the crimping mold is 0.05 mm or more and is not more than twice the peripheral surface thickness of the battery case. A method of sealing a battery. Claim that the lower surface of the angular contact with the open end of the battery case to implement the final crimping step (d) by caulking die used as formed in a predetermined taper angle that is inclined depression-side towards the center of the battery case 2. A method for sealing a cylindrical battery according to 1 .

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