JPH0744030B2 - Sealing body for cylindrical alkaline batteries - Google Patents

Description

The present invention relates to a sealing body for a tubular alkaline battery.

[Conventional technology]

In recent years, in cylindrical alkaline batteries, in order to improve resistance to liquid leakage, for example, as shown in FIG. 14, a concave groove 1a for receiving the sealing body 5 is provided near the opening end of the positive electrode can 1, Into the opening of the can 1, the sealing body 5 in which the current collector 6 as the negative electrode side current collector and the annular support 13 are mounted is inserted, and the portion beyond the recessed groove 1a corresponding to the opening end of the positive electrode can 1 is inward. That is, it is tightened in the radial direction, and its inner peripheral surface is pressed against the sealing body 5,
A sealing structure for sealing the opening of the positive electrode can 1 has been adopted (for example, JP-A-56-138858, JP-A-56-138860, and JP-A-58-174865). .

Cylindrical alkaline battery sealing body 5 having such a sealing structure
For example, as shown in FIG. 10, a cylindrical thick collector rod holding portion 16 having a through hole 15 into which the collector rod 6 is press-fitted is provided in the central portion.
And an outer peripheral thick portion 17 whose outer peripheral surface is in pressure contact with the inner peripheral surface of the opening end portion of the positive electrode can 1, and the collector rod penetrating side 16b of the collector rod holding portion 16.
Connecting portion 1 for connecting the end portion of the outer peripheral thick portion 17 and the upper end portion 17a of the thick outer peripheral portion 17
The connecting portion 18 is provided with an annular or partially discontinuous annular thin-walled portion 19 in the vicinity of the current collector holding portion 16, and when the internal pressure of the battery rises abnormally, the thin-walled portion 19 is formed. Safety measures have been taken to prevent the gas that had broken and accumulated inside the battery from escaping to the outside, and the pressure inside the battery becoming too high to cause the battery to explode. Especially recently
From the viewpoint of preventing environmental pollution, it is required to reduce or eliminate the amount of mercury that amalgamates zinc as a negative electrode active material. If the amount of mercury is reduced to meet the demand, the battery will be reduced accordingly. Since hydrogen gas is likely to be generated inside and the pressure inside the battery tends to rise abnormally, it is an important requirement to provide the battery with a highly reliable explosion-proof function.

In order to break the thin portion 19 of the sealing body 5 at a constant gas pressure for such a purpose, the sealing body 5 must be molded so that the variation in the thickness of the thin portion 19 is small. I won't. Further, when such a thin portion 19 is provided, it becomes difficult for the resin to flow at the time of molding the sealing body. Therefore, it is very important to design the shape of the sealing body and set the position of the resin injection gate.

By the way, as a resin injection gate system for molding such a sealing body 5, the following can be considered.
For example, as shown in FIG. 15, the outer peripheral thick portion 17 of the sealing body 5
The side gate method 23a in which the resin is injected from the outer peripheral side, similarly, the resin is injected from the outer peripheral side of the thick outer peripheral portion 17, but the injection position is almost the central portion in the thickness direction of the sealing body 5, and the gate cutting finish is made with gold. Submarine gate system improved with a mold structure 23
b, or a pinpoint gate system 23c in which resin is injected from a part of the connecting portion 18 as shown in FIG. 16, and further,
As shown in FIG. 11, a center disk gate method 23d in which a film-shaped closing portion 21 is formed above the through hole 15 into which the current collecting rod 6 is press-fitted and the resin is injected from this portion can be considered.

However, in the side gate method 23a, the submarine gate method 23b, or the pinpoint gate method 23c, as shown in FIGS. 15 (b) and 16 (b), respectively, the flow of resin (the flow of resin is indicated by an arrow). ) Is not fixed,
Since the injected resin flows irregularly, the resins having different flow directions collide with each other to form a weld line 22 which is a boundary layer of the resins. The weld line 22 is formed by hitting the leading portions of the resins that have flowed in different directions in the cold mold, and is formed by joining the resins whose temperatures have dropped slightly. Therefore, in this weld line 22, the resin is not sufficiently melted, and therefore the strength becomes smaller than the other portions, which may cause cracks.

Further, in the above-mentioned gate method, the flow distance of the resin becomes long, so the gas inside the mold is not expelled, so-called gas escape does not work well, air bubbles are trapped, and seizure occurs due to poor gas escape. It will be easier. In addition, if the injection pressure of the resin is set high in order to improve the gas escape in the mold, the burr from the mold dividing surface will become large, and a process for burr removal will be required, or burr removal will be complete. If this is not possible, problems such as deterioration of the quality of the sealing body occur.

On the other hand, as shown in FIG. 11, in the center disk gate method 23d in which the resin is injected from the central portion of the sealing body 5, the flow direction of the resin regularly flows radially in a radial direction.
There is no weld line due to the collision of resins with different flow directions, and because the resin flows in the radial direction, the flow distance is short, and the gas inside the mold quickly escapes from the center of the mold to the outer periphery. Therefore, there is an advantage that the resin flow in the thin portion is uniform and the sealing body with stable dimensions can be molded. Recently, the center disk gate method is most often used for molding this kind of sealing body. (For example, JP-A-59-8265,
(Kaikai No. 57-188255 and No. 57-188256).

As shown in FIG. 10, the sealing body 5 molded by such a center disk gate method has a film-shaped closing portion 21 formed above the through hole 15 into which the current collecting rod 6 is inserted. The closing portion 21 is ruptured by the press-fitting of the tip portion 6a of the collector rod 6. Therefore, the collector rod 6 should have a through hole 15
Since it is necessary to insert it with a strong pressure inside, there is a possibility that a large force is applied to the end of the current collector holding side 16 of the current collector penetrating side 16b and the sealing body is destroyed. As disclosed in Japanese Patent Publication No. 57-194452, the blocking portion 21
Notch the periphery of the collector bar, and connect the collector bar holding part 16 to the collector bar penetrating side 16b.
An accommodating portion 24 for accommodating the cut-off piece of the blocking portion 21 ruptured by the press-fitting of the collector rod 6 is provided on the end of the collector rod 6 so that a large force is not applied to the end portion of the collector rod holding portion 16 on the side where the collector rod penetrates. Things have also been incorporated.

However, when the closing portion 21 is broken by the press-fitting of the current collector rod tip portion 6a, as shown in FIG. 12, the closing portion 21 broken by the current collecting rod 6 has a small but visible V-shaped crack.
21a occurs at several places. Current collector rod 6 press-fitted into the through hole 15
The outer diameter D ₂ of the current collector 6 is designed to be larger than the inner diameter D _{1 of the through} hole 15 by about 15 to 65% in order to enhance the tightness between the current collector 6 and the sealing body 5, so that the current collector 6 is press-fitted. By the rift above
21a is constantly exerted with a force to push the crevice 21a apart.

If a battery manufactured in such a state is left for a long time,
The V-shaped split 21a gradually expands with the passage of time, and the end portion 16b of the current collector holding portion 16 on the side where the current collector penetrates, the thin portion 19 for explosion-proof, and further the current collector holding portion 16 of the current collector holding portion 16. Collector rod 6
The crack spreads to the portion compressed between the ring support 13 and the annular support 13, and as a result, the electrolytic solution leaks to the outside of the sealing body. In particular, it has been also observed that the stress cracking progresses rapidly when stored for a long time under a high temperature condition of 60 ° C. or higher and 90 ° C. or lower.

[Problems to be solved by the invention]

The present invention is to reduce the leakage resistance caused by piercing the film-like closed portion at the upper part of the through hole which the conventional product has with the current collector rod, or molding when a gate method other than the center disk gate method is adopted. Solves problems such as generation of weld lines due to irregular resin flow and deterioration of sealing material quality due to long resin flow distance, and high reliability for liquid leakage resistance and battery explosion prevention It is an object of the present invention to provide a sealing body for a cylindrical alkaline battery that secures the above.

[Means for solving problems]

The present invention provides a recess having an annular bottom portion around the upper end of the through hole on the inner peripheral side of the current collector holding side in which the through hole for press-fitting the negative electrode current collector is provided in the central portion, The bottom of the recess is provided with two or three protrusions whose upper end is located below the lower surface of the explosion-proof thin portion so as to face each other in the diametrical direction, or three at substantially equal intervals in the circumferential direction. The upper end on the inner peripheral side is a resin injection gate.

That is, by providing two or three convex portions on the bottom of the concave portion provided on the current collector holding portion as described above, and using the inner peripheral side upper end portion of the convex portion as a resin injection gate, As shown in the conventional center disk gate method, the closed part at the top of the through hole is no longer formed unlike the conventional sealing body, so it is not necessary to pierce the closed part at the top of the through hole with the tip of the current collector rod, and the rupture of the closed part The decrease in liquid leakage resistance that has occurred based on is solved. Of course, the gate portion at the upper end on the inner peripheral side of the convex portion is 2 along the extension line of the inner peripheral surface of the through hole.
There are 3 or 3 pieces intermittently, and their gates are located in the axial direction of the through hole (longitudinal direction in the figure), so when the current collector rod is pressed into the through hole, it tries to expand. The force is not applied to the gate part. Therefore, even if minute irregularities occur in the gate portion due to gate cutting in the mold structure, these minute irregularities do not gradually expand over time, and always expand by press fitting the current collector rod. Since the inner peripheral surface of the annular bottom portion 25a to which a force is applied is a smooth surface and the portion between the convex portions extends, no rupture occurs even when the current collector rod is press-fitted. In addition, since the upper end position of the through hole is lower than the lower surface of the explosion-proof thin portion by providing the concave portion in the current collecting rod holding portion, the current collecting rod holding portion is pressed when the current collecting rod is pressed into the through hole. Since the force does not reach the thin wall portion, the thin wall portion is prevented from being deformed or damaged, and the thin wall portion can be destroyed according to the set pressure, so the reliability of the explosion prevention of the battery becomes high. Furthermore, regarding moldability, resin is injected from almost the center of the sealing body, so the resin flow is more uniform and the resin flow distance is longer than in the side gate method, submarine gate method, or pinpoint gate method. short. Also, two convex portions whose inner upper ends are resin injecting gates are provided in the annular bottom portion of the concave portion located near the center of the sealing body so as to be diametrically opposed, or three at substantially equal intervals in the circumferential direction. Since the resin injection gates are provided individually, the resin injection gates are close to each other in the substantially central portion of the sealing body, so that substantially no weld line is generated. Moreover, the injected resin flows to the thick wall portion around the recess where it easily flows and then flows to the thin wall portion, so that the resin flow in the thin wall portion becomes uniform and the thin wall portion becomes uniform. It is excellent in moldability such as being formed to a thickness, and a high quality sealing body can be stably obtained.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an embodiment of the tubular alkaline battery sealing body of the present invention. In FIG. 1, the upper end portion of the current collecting rod is also shown. FIG. 2 is a perspective sectional view of a main part of the sealing body shown in FIG. FIG. 3 is a perspective view of an essential part showing a state where a current collecting rod is press-fitted into the sealing body shown in FIG. 1, and FIG.
FIG. 4 is a cross-sectional view of a main part showing a state where a current collector rod is press-fitted into the sealing body shown in the drawing and corresponds to a cross section taken along line XX of FIG. Fifth
The figure is a partially sectional front view showing an example of a cylindrical alkaline battery using the sealing body shown in FIG. In addition, in the sectional views other than FIG. 2 and FIG. 8 described later, in order to avoid complication of the drawing, the contour line on the rear side of the inside of the sealing body or the inside of the battery is the inside of the current collector holding portion. It is omitted except for the peripheral side.

First, the outline of a cylindrical alkaline battery using the sealing body of the present invention will be described with reference to FIG.

In FIG. 5, 1 is a positive electrode can, 2 is a positive electrode mixture, 3 is a separator, 4 is a negative electrode agent, and 5 is a sealing body. 6 is a collector rod as a negative electrode side current collector, 7 is a leaf spring, and 8 is a negative electrode terminal plate. Reference numeral 9 is a paper insulating ring, 10 and 11 are heat-shrinkable resin tubes, 12 is a metal jacket, 13 is an annular support, and 14 is a positive terminal plate.

When assembled, the battery is upside down from the state shown in FIG. 5, the positive electrode can 1 has a cylindrical shape with a bottom, and manganese dioxide is used as a positive electrode in the positive electrode can 1. A positive electrode mixture 2 formed as a substance in a cylindrical shape, a separator 3 formed in a cup shape, and a negative electrode agent 4 made of a kneaded product of zinc powder and a gelled alkaline electrolyte are sequentially loaded. Then, in the opening of the positive electrode can 1, a brass current collector rod 6 is press-fitted into a through hole in the central portion, and a metal annular support 13 having a gas vent hole 13a is formed.
The opening 5 of the positive electrode can 1 is sealed with the sealing member 5 fitted with the sealing member 5 fitted therein, and the portion beyond the concave groove 1a corresponding to the opening end of the positive electrode can 1 is tightened inward, that is, in the radial direction. To be done. After sealing the opening of the positive electrode can 1, a heat-shrinkable resin tube
10, the insulating ring 9, the leaf spring 7, the negative electrode terminal plate 8, and the positive electrode terminal plate 14 are respectively arranged at predetermined positions and fixed with the heat-shrinkable positive resin tube 11, and then the resin insulating ring (not shown) is used as the positive electrode. The battery is assembled by disposing it on the heat-shrinkable resin tube 11 on the peripheral portion of the terminal plate 14 and then tightening it with the metal jacket 12.

The sealing body 5 is formed of an elastic synthetic resin such as nylon, polyethylene or polypropylene, and as shown in detail in FIG.
Cylindrical thick-walled collector rod holding portion 16 having a through hole 15 for press-fitting
Is provided on the outer peripheral side thereof, and an outer peripheral thick-walled portion 17 is provided in pressure contact with the inner peripheral surface of the opening end of the positive electrode can 1, and the end portion of the collector rod holding portion 16 on the side of the collector rod penetrating side 16b is provided. A connecting portion 18 for connecting the upper end portion 17a of the outer peripheral thick portion 17 is provided.

In this specification, when the current collector 6 is press-fitted into the through hole 15 of the sealing body 5, the side where the current collector 6 is inserted (current collector insertion side 16a).
The reference side) is the lower side, and the side through which the current collecting rod 6 penetrates (see the current collecting rod penetrating side 16b) is the upper side. The connecting portion 18 is provided with a thin portion 19 for explosion protection near the current collector holding portion 16.
An inverted V-shaped portion 20 is provided near the outer peripheral thick portion 17 of the connecting portion 18. The thickness of the thin portion 19 and the set breaking pressure thereof vary depending on the material of the sealing body and the size of the battery. For example, in an AA battery, the thickness of the thin portion 19 is generally 0.15 to 2.0 m.
m, and the burst pressure is generally set to 50-60 kg / cm ² . By the way, when exemplifying other batteries, the thickness of the thin portion 19 is generally set to 0.15 to 2.0 mm, but the breaking pressure is generally 15 to 25 kg / cm ² for AA batteries and generally for AA batteries. 20 to 30 kg / cm ² , 60 to 70 kg for AAA batteries
/ cm ² , for AA batteries, it is generally set to 50-60 kg / cm ² . Further, the thin portion 19 is provided in the vicinity of the collector rod holding portion 16, because the collector rod holding portion 16 is fixed with a thick wall, so that it is provided in the vicinity thereof corresponds to the increase of the internal pressure. Since it is easy to tear and the inner diameter of the thin part 19 is small,
This is because the area of 19 does not become large and the pressure per unit area increases even at low pressure, and the thin portion 19 can be destroyed before the pressure becomes too high. The inner surface of the inverted V-shaped portion 20 serves as a guide portion for the tip of the separator 3, and when the positive electrode can 1 is closed, it is slightly bent in the radial direction to facilitate tightening of the positive electrode can 1 in the radial direction. It helps, but it is not always necessary.

A metal annular support 13 having a gas vent hole 13a is mounted between a portion near the collector rod insertion side 16a of the collector rod holding portion 16 and the outer peripheral thick portion 17. As described above, the inner diameter D ₁ of the through hole 15 into which the current collecting rod 6 is press-fitted and corresponding to the annular support 13 is designed to be slightly smaller than the outer diameter D _{2 of} the current collecting rod 6, and By press-fitting into the through hole 15, the current collector rod holding portion 16 in that portion is pressed outward in the radial direction. Then, the portion of the current collector holding portion 16 interposed between the current collector 6 and the annular support 13 is tightened inwardly from the concave groove 1a of the positive electrode can 1 so as to support the current collector 6 and the annular support. The body 13 is strongly compressed, and the portion of the outer peripheral thick portion 17 interposed between the positive electrode can 1 and the annular support 13 is strongly compressed by the positive electrode can 1 and the annular support 13, whereby the sealing body 5 is high. The opening of the positive electrode can 1 is hermetically sealed.

On the inner peripheral side of the current collector holding side 16b of the current collector penetrating side 16b, there is provided a concave portion 25 whose inner peripheral surface gradually increases upward,
The bottom portion 25a of the recess 25 is formed in an annular shape around the upper end of the through hole 15, and the bottom portion 25a is provided with a prismatic protrusion 26 whose outer peripheral side is integrated with the inner peripheral surface of the recess 25. . Although only one projecting portion 26 is visible in FIGS. 1 and 2, two or three projecting portions 26 are provided in the present invention, and in this embodiment, as shown in FIG. Two are provided. The inner peripheral surface of the convex portion 26 is on the extension line of the inner peripheral surface of the through hole 15, and the upper end portion 26a on the inner peripheral side of the convex portion 26 serves as a resin injection gate when molding the sealing body 5. ing.

FIG. 3 shows the main part on the side where the current collector 6 penetrates when the current collector 6 is press-fitted into the through hole 15 of the sealing body 5 in which the two convex portions 26 are provided so as to face each other in the diameter direction as described above. FIG. 4 is a perspective view, and FIG. 4 is a cross-sectional view of an essential part in this state, which corresponds to a cross section taken along line XX of FIG.

FIG. 6 is a perspective view showing a main part of another embodiment of the sealing body of the present invention. In the embodiment shown in FIG. 6, the convex portion 26 is substantially equal to the bottom portion 25a of the concave portion 25 in the circumferential direction. Three are provided at intervals. Also in this embodiment, the inner peripheral surface of the convex portion 26 is on the extension line of the inner peripheral surface of the through hole 15, and the upper end portion 26a on the inner peripheral side of the convex portion 26 is made of resin for molding the sealing body 5. It is an injection gate. In the present invention, the upper end portion 26a on the inner peripheral side has two or three convex portions 26 serving as resin injection gates.
What is specified as individual pieces is that it is difficult to make the resin flow uniform with one piece, and with 4 or more pieces, it is considered that the same effect as in the case of two or three pieces is theoretically obtained, but the sealing body This is because it is difficult to properly provide four or more convex portions 26 on the bottom portion 25a of the small concave portion 25 having a diameter of about 2 to 3 mm provided near the central portion. Further, when two convex portions 26 are provided, they are provided so as to face each other in the diametrical direction, and when three convex portions 26 are provided, it is necessary to provide three convex portions 26 at substantially equal intervals in the circumferential direction so that the resin flow is substantially equal. This is to make it uniform.

As described above, the width of the inner peripheral side of the convex portion 26 having the resin injection gate at the time of molding at the inner peripheral side upper end thereof is 10 to the inner periphery of the through hole 15.
It is preferable to set it to about 20%. In particular, when two convex portions 26 are provided, the width of the inner peripheral side of the convex portion 26 is
About 12 to 17%, and when three convex portions 26 are provided, it is preferable to set the width of the inner peripheral side of the convex portion 26 to about 10 to 15% of the inner periphery of the through hole 15. This is because when the width of the inner peripheral side of the convex portion 26 is smaller than the above range, the gate cross-sectional area becomes small, the flow of the resin deteriorates, molding becomes difficult, and the width of the inner peripheral side of the convex portion 26 becomes smaller. If the width is larger than the above range, the traces of tearing off the gate portion may be elongated or the gate portion may be chipped when tearing off the gate. And the convex part
If the height of 26 is such that the upper end of the convex portion 26 is lower than the lower surface of the explosion-proof thin portion 19, the force at the time of press-fitting the current collector rod is
Since it does not reach 19, the size is usually set to be almost the same as the width on the inner peripheral side.

In this way, the current collector holding side of the sealing body 5 of the current collector holding portion 16 on the current collector penetration side
16b is provided with a concave portion 25, and two convex portions 26 or three convex portions 26 are provided at a bottom portion 25a of the concave portion 25 so as to face each other in the diametrical direction. By using 26a as the resin injection gate, even if the collector rod 6 having an outer diameter larger than the inner diameter of the through hole 15 is strongly pressed into the through hole 15,
Since the closing part 21 such as the sealing body by the center disk gate method shown in the figure is not broken, no tear is generated,
The stress cracking due to the press-fitting of the collector rod 6 does not occur even if stored for a long time. A battery using the sealing body of the present invention and
The difference in the leakage resistance under high temperature storage of the battery using the conventional sealing body according to the center disk gate system shown in FIG. 10 is as shown in Table 1 below.

Table 1 shows the batteries A and B using the sealing body of the present invention and the 10th table.
FIG. 8 shows the results of a liquid leakage resistance test of a battery C using a conventional sealing body according to the center disk gate method shown in the figure. The batteries used in the test are AA alkaline batteries having the structures shown in FIGS. 5 and 14, and the current collector rods used in these batteries all have an outer diameter of 1.5 mm. All the sealing bodies are made of nylon 66, outer diameter 13 mm, total height 4 mm,
The inner diameter of the through hole is 1.2 mm. The sealing body used in the battery A is that of the embodiment shown in FIG. 1, and two convex portions 26 are provided on the bottom portion 25a of the concave portion 25 so as to face each other in the diametrical direction. The depth is 1.3 mm and the width of the bottom 25a of the recess 25 is
The width of the inner peripheral side of the convex portion 26 is 0.4 mm and is 0.5 mm, which corresponds to 13.5% of the inner periphery of the through hole 15. And the height of the convex portion 26 is
The upper end portion 26a on the inner peripheral side of the convex portion 26 is 0.5 mm and serves as a resin injection gate at the time of molding the sealing body. The sealing body 5 used for the battery B is that of the embodiment shown in FIG.
Three pieces are provided on the bottom portion 25a of the 25 at substantially equal intervals in the circumferential direction, and the width of the convex portion 26 on the inner peripheral side is 0.4 mm.
It is equivalent to 0.8%. The inner peripheral side upper end portions 26a of the three convex portions 26 are resin injection gates, and other specifications are the same as those of the sealing body used in the battery A. In addition, the closing portion 21 of the sealing body used in the battery C
Has a thickness of 0.2 mm.

For the leak resistance test, 100 batteries A, B, and C, 60 each
The denominator of the numerical values shown in Table 1 is the number of batteries used in the test, and the numerator is the number of batteries in which leakage has occurred.

As shown in Table 1 above, the batteries A and B using the sealing body of the present invention are superior to the battery C using the conventional sealing body of the center disk gate system in leakage resistance under high temperature storage. ing.

Further, in the conventional sealing body 5 of the center disk gate system shown in FIG. 10, although the accommodating portion 24 for the cut-out piece of the closing portion 21 is provided, the closing portion 21 and the thin portion 19 are provided.
Since and are located on substantially the same plane, the force of piercing the blocking portion 21 above the through hole 15 with the current collector 6 and the force of expanding the diameter by press-fitting the current collector rod act on the explosion-proof thin portion 19. The first
As shown in FIG. 13, the thin portion 19 may be distorted, and in the worst case, the thin portion 19 may be bent and broken. Since it is not necessary to break through 21, it is possible to make the force at the time of press-fitting the current collector rod smaller than before, and by providing the recess 25, the upper end position of the through hole 15 is lower than the lower surface of the thin portion 19. Therefore, since the force due to the press-fitting of the collector rod 6 does not reach the thin portion 19, the thin portion 19 is not deformed or damaged, and the function of the thin portion 19 can be stably exhibited as set. it can.

Also from the viewpoint of moldability, the sealing body of the present invention, as shown in FIGS. 1 and 6, has an inner peripheral side of the convex portion 26 in which the resin injection gate is provided near the center of the sealing body 5. Since it is provided at the upper end 26a, the flow of resin is almost the same as in the case of the conventional center disk gate method, and it regularly and radially flows in a radial direction, so that a substantial weld line is generated. Moreover, since the flow distance is short, there is no gas escape failure. Further, the resin injection gate is below the thin portion 19, and the resin injected into the mold flows to the thick and easily flowable collecting rod holding portion around the recess 25 and then flows to the thin portion 19. Therefore, the resin flow in the thin portion 19 is uniform and the thickness of the thin portion 19 is also uniform.

This will be described below with reference to FIG. 7 by taking the sealing body shown in FIG. 1 as an example. FIG. 7 is a view for explaining the resin flow of the sealing body shown in FIG. 1, and FIG. 7 (a) is a cross-sectional view of the sealing body (however, unlike FIG. 1, two convex portions are shown.
26 is shown as a cut surface to be cut together. Further, in the actual product, the outer peripheral side of the convex portion 26 and the inner peripheral surface of the concave portion 25 are integrated, but in order to easily understand the position of the convex portion 26, the outer peripheral side surface of the convex portion 26 and the inner portion of the concave portion 25 are A dashed-dotted line is drawn on the boundary with the peripheral surface and the boundary between the lower end surface of the convex portion 26 and the bottom portion 25a of the concave portion 25),
FIG. 7 (b) is a bottom view thereof. First, FIG. 7 (a)
The resin injected from the resin injection gate provided on the upper end 26a on the inner peripheral side of the convex portion 26 holds the collector rod that is thick and easily flows around the concave portion 25 as indicated by the arrow. Since the resin flows in the thin portion 19 after flowing into the portion 16, the resin flow in the thin portion 19 becomes uniform, and as a result, the thickness of the thin portion 19 becomes uniform. Further, since the resin is injected from the upper end portion 26a on the inner peripheral side of the convex portion 26 near the center of the sealing body 5, as shown by the arrow in FIG. Since the flow flows in a radial direction regularly and uniformly, no substantial weld line is generated,
In addition, since the flow distance is short, the occurrence of gas escape defects is eliminated.

FIG. 8 is a perspective sectional view of a main part of still another embodiment of the cylindrical alkaline battery of the present invention, and FIG. 9 is a sectional view taken along the line YY of FIG. In the embodiment shown in FIGS. 8 to 9, two convex portions 26 are provided so as to face each other in the diametrical direction, similarly to the sealing body shown in FIG. The difference is that in the sealing body shown in FIG. 1, the outer peripheral side of the convex portion 26 is integrated with the inner peripheral surface of the concave portion 25, but in this embodiment the outer peripheral side surface of the concave portion 26 and the inner peripheral surface of the concave portion 25 are Are separated from each other, and there is a gap therebetween, and the convex portion 26 is provided on the concave portion 25 in an independent state. In the sealing body shown in FIGS. 8 to 9 as well, similar to the sealing body shown in FIGS. 1 and 6 described above, high leak resistance and high reliability for preventing explosion of the battery can be secured. Further, in the above description regarding the flow of the resin of the sealing body, the sealing body shown in FIG. 1 is taken as an example, but also in the sealing body shown in FIGS.
Also in the sealing body shown in the figure, the flow of the resin is the same as in the case of the sealing body shown in FIG. 1, and all have good moldability,
It is possible to consistently obtain high quality products.

〔The invention's effect〕

As described above, in the present invention, the concave portion is provided on the inner peripheral side of the current collector holding portion on the side through which the current collector penetrates, and two or three convex portions are provided on the bottom of the concave portion in a specific mode. By using a resin injection gate on the inner peripheral side upper end, even if the current collector is pressed into the through hole, no cracks will occur in the gate part, and stress cracking due to press-fitting of the current collector also occurs during long-term storage. I was able to get rid of it. In addition, since the upper end of the through hole and the explosion-proof thin-walled part were displaced due to the provision of the recess, the force applied to the current-collecting rod holding part by press-fitting the current-collecting rod was not applied to the thin-walled part. Since the deformation and damage of the part are eliminated and the thin part can be destroyed by the set gas internal pressure, it is possible to improve the reliability for preventing the battery from exploding. Furthermore, since the resin injection gate is provided near the center of the sealing body, the resin flow is uniform and the flow distance is short, so there is no substantial weld line generation, and the moldability is a side gate method,
It is superior to the submarine gate method and pinpoint gate method, and is closer to the center disk gate method.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the sealing body for a cylindrical alkaline battery of the present invention, FIG. 2 is a perspective sectional view of a main part of the sealing body shown in FIG. 1, and FIG. 3 is FIG. FIG. 4 is a perspective view of relevant parts when the current collector rod is press-fitted into the sealing body shown in FIG. 4, and FIG. 4 is a sectional view of relevant parts when the current collector rod is press-fitted into the sealing body shown in FIG. FIG. 5 is a partial cross-sectional front view showing an example of a cylindrical alkaline battery using the sealing body of the present invention. FIG. 6 is a perspective view of an essential part of another embodiment of the tubular alkaline battery sealing body of the present invention. FIG. 7 is a view for explaining the resin flow of the sealing body shown in FIG. 1, FIG. 7 (a) is a sectional view of the sealing body, and FIG. 7 (b).
Is a bottom view thereof. FIG. 8 is a perspective sectional view of a main part showing still another embodiment of the tubular alkaline battery sealing body of the present invention, and FIG. 9 is a sectional view taken along line YY of FIG. FIG. 10 is a cross-sectional view showing a conventional cylindrical alkaline battery sealing body according to the center disk gate method, and FIG. 11 is a view for explaining the resin injection gate and the resin flow of the sealing body shown in FIG. FIG. 11 (a) is a sectional view of the sealing body, and FIG. 11 (b) is a bottom view thereof. FIG. 12 is a perspective view of a main part showing a state where the current collector rod is press-fitted into the sealing body shown in FIG. 10, and FIG. 13 is a cross-sectional view of the main part showing a state where the current collection rod is press-fitted into the sealing body shown in FIG. First
FIG. 14 is a partial sectional front view of a cylindrical alkaline battery using the sealing body shown in FIG. FIG. 15 is a view for explaining a resin injection gate and a resin flow of a conventional tubular alkaline battery sealing body by a side gate method or a submarine gate method, and FIG. 15 (a) is a sectional view of the sealing body, Figure 15 (b)
Is a bottom view thereof. FIG. 16 is a view for explaining a resin injection gate and a resin flow of a conventional cylindrical alkaline battery sealing body by a pinpoint gate system, and FIG. 16 (a) is a sectional view of the sealing body, FIG. (B) is the bottom view. 1 ... Positive electrode can, 2 ... Positive electrode mixture, 3 ... Separator, 4
...... Negative electrode agent, 5 ...... Sealing body, 6 ...... Current collector, 13 ...... Ring support, 15 ...... Through hole, 16 ...... Current collector holding part, 16b ...... Current collector penetration side, 17 ...... Peripheral thick part, 17a ... Upper end, 18 ...
… Connecting part, 19 …… Thin-walled part, 25 …… Recessed part, 25a …… Bottom of recessed part, 26 …… Convex part, 26a …… Inner peripheral side upper end part

Claims (1)

[Claims] 1. A tubular collector rod holding portion (16) having a through hole (15) into which a collector rod (6) is press-fitted, and an outer peripheral surface of the cylindrical collector rod holding portion (16) of the positive electrode can (1). An outer peripheral thick portion (17) to be pressed against the inner peripheral surface, an end portion of the collector rod holding portion (16) on the side of the current collector penetrating side (16b) and an upper end portion (17a) of the outer peripheral thick portion (17). And a thin portion (19) for explosion protection is provided in the vicinity of the collector rod holding portion (16) of the connecting portion (17),
In addition, for a resin cylindrical alkaline battery in which a hard annular support (13) having a gas vent hole (13a) can be arranged between the current collector holding portion (16) and the outer peripheral thick portion (17). In the sealing body, the current collector holding portion (16) has a current collector penetrating side (16
On the inner peripheral side of b), the annular bottom (2
5a) is provided with a concave portion (25), and a convex portion (26) whose upper end is located below the lower surface of the explosion-proof thin portion (19) is diametrically formed in the bottom portion (25a) of the concave portion (25). A cylindrical alkaline battery, characterized in that two or three are provided so as to face each other at substantially equal intervals in the circumferential direction, and the upper end portion (26a) on the inner peripheral side of the convex portion (26) is a resin injection gate. Sealed body.