JPH0537415Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a cylindrical alkaline battery, and more specifically, a cylindrical alkaline battery constructed by welding a positive terminal to the bottom of a bottomed cylindrical positive electrode can. It is related to.

<Conventional technology> Cylindrical alkaline batteries have a structure in which a power generation element is housed in a bottomed metal positive electrode can, and the opening is sealed with an insulating gasket and a terminal plate that also serves as a negative electrode terminal. unit cells are used.

This type of unit cell uses a positive electrode can with a flat bottom and integrates the positive terminal plate with the bottom of the positive electrode can after fabrication.
There is a type in which the bottom of the positive electrode can is previously processed into a convex shape and the positive terminal is integrally formed on the bottom of the positive electrode can.

Among these, the former type, which uses a positive terminal plate separate from the positive electrode can, is widely used in large batteries such as LR20.

This type of battery generally employs a structure in which the positive terminal is closely attached to the bottom surface of the positive electrode can, and then the positive terminal is fixed to the positive electrode can by resistance welding or the like at the periphery of the bottom surface of the positive electrode can. The periphery of the bottom of the positive electrode can is the strongest in the positive electrode can and is difficult to deform, and during welding, it will not deform even if the pressure from the welding electrode is applied. Therefore, welding can be performed reliably, and the exterior can be removed later. This is because when welding is performed, it is easy to hide welding marks and does not impair the appearance of the product.

<Problems to be solved by the invention> By the way, when a battery is sealed by combining a negative terminal plate and an insulating gasket into the opening of a positive electrode can, the pressure inside the positive electrode can increases due to the air trapped during the combination. The center of the bottom may swell.

In this case, as shown in FIG.
Since the central part of the positive electrode can is pushed upward in the figure, it is difficult to bring the positive electrode can 9 and the positive electrode terminal 10 into close contact at the welding part, and when resistance welding is performed at the periphery of the bottom of the positive electrode can as described above, sufficient welding current is required. There is a problem that it does not flow and it becomes impossible to weld the two properly.

In order to prevent such deformation of the bottom of the positive electrode can, it is conceivable to increase the wall thickness of the positive electrode can, but the increased wall thickness reduces the capacity of the power generation elements, resulting in a decrease in battery performance.

<Means for Solving the Problems> This invention provides a cylindrical alkaline battery in which a positive electrode terminal is integrated with the positive electrode can by welding at the outer periphery of the bottom of the positive electrode can. A portion, a bead portion, a second flat portion, and a central protruding terminal portion are sequentially formed substantially concentrically, and the second flat portion is raised from the first flat portion on the side opposite to the bottom surface of the positive electrode can. The gist is what was said.

In addition, instead of devising the shape of the positive electrode terminal as described above, the bottom surface of the positive electrode can is
The bead portion and the central flat portion may be sequentially formed substantially concentrically, and the central flat portion may be recessed from the outer peripheral flat portion.

<Function> By devising the shape of the positive terminal or the bottom of the positive electrode can as described above, even if the internal pressure of the battery can rises and the center of the positive electrode can bulges, the second flat part of the positive terminal can be pushed up. This prevents a decrease in the adhesion between the positive terminal plate and the positive electrode can at the outer periphery of the bottom of the positive electrode can.

<Example> Examples will be described below.

In the positive electrode terminal 1 shown in FIG. 1A, a first flat part 1a, a bead part 1b, a second flat part 1c, and a central protruding terminal part 1d are formed in order from the outer periphery in substantially concentric circles.

Of these, three welding protrusions are formed on the same circumferential surface at approximately equal intervals on the surface of the first flat portion 1a facing the positive electrode can. In addition, the second flat part 1c has a dimension t1, specifically about 0.2 to 0.6 mm, above the first flat part 1a in the figure (when the positive electrode terminal 1 is brought into close contact with the bottom surface of the positive electrode can as described later). It is floated on the opposite side of the bottom of the positive electrode can.

The dimension t1 specified above is 0.2mm.
If the diameter is smaller than 0.6 mm, the difficulty of welding the positive electrode terminal 1 and the bottom surface of the positive electrode can will not be sufficiently solved, and if the diameter is larger than 0.6 mm, the terminal strength of the positive terminal 1 will decrease.

After the power generation element is housed, the positive electrode terminal 1 is tightly attached to the bottom of the positive electrode can 2, the opening of which is sealed with a terminal plate and a synthetic resin gasket, as shown in FIG. 1B.

Here, on the bottom surface of the positive electrode can 2, from the outside, there is an outer peripheral flat part 2a, and a bead part 2 higher than this outer peripheral flat part 2a.
b, and a central flat part 2c having the same height as the outer circumferential flat part 2a are sequentially formed, and when the positive electrode can opening is sealed, the central flat part 2c bulges out slightly as shown in the figure. Since the second flat portion 1c of the positive electrode terminal 1 facing the flat portion 2c is raised as described above, the close contact between the first flat portion 1a of the positive electrode terminal 1 and the outer peripheral flat portion 2a of the positive electrode can 2 is impaired. It won't happen.

Next, the positive electrode terminals 1 are welded and integrated with the positive electrode can 2 by resistance welding while pressing a welding electrode against the upper surface of the first flat portion 1a corresponding to the welding protrusion from the upper side in the figure.

FIG. 1c shows a completed battery obtained by attaching a heat-shrinkable adhesive label 6 for the exterior to the outer periphery of the unit cell produced in this way. 5 is a positive electrode mixture, and 5 is a separator.

On the other hand, FIGS. 2A to 2B show other embodiments, and in FIG. 2A, the bottom surface of the positive electrode can 7 has an outer peripheral flat part 7a, a bead part 7b, and a central flat part 7c approximately from the outer periphery. They are formed sequentially in concentric circles.

The central flat part 7c is recessed from the outer peripheral flat part 7a by a dimension t2, specifically about 0.2 to 0.6 mm, to the lower side in the figure (the side opposite to the bottom surface of the positive electrode can when the positive electrode terminal is in close contact with it). .

Here, if the dimension t2 is smaller than 0.2 mm, the difficulty of welding the positive electrode terminal and the bottom surface of the positive electrode can will not be sufficiently solved, while if it is larger than 0.6 mm, the terminal strength of the positive electrode terminal will be reduced.

Then, the power generating element is housed in the positive electrode can 7, and after the opening is sealed with a terminal plate and a synthetic resin gasket, the positive electrode terminal 8 is brought into close contact with the bottom surface of the positive electrode can as shown in FIG. 2B.

Here, a first flat part 8a, a bead part 8b, and a second flat part 8c having the same height as the first flat part 8a are sequentially formed on the positive electrode terminal 8 from the outside. Furthermore, when the opening is sealed as described above, the central flat part 7c of the positive electrode can 7 bulges out slightly as shown in the figure, but since the central flat part 7c is recessed as described above, the positive electrode terminal 8 and Adhesion to the bottom of the positive electrode can is not impaired.

Thereafter, as in the example shown in FIG. 1c, a heat-shrinkable adhesive label is attached to this unit cell to form a completed battery.

In addition to the above, if necessary, a configuration in which the second flat part of the positive electrode terminal is raised above the first flat part and a configuration in which the central flat part of the bottom surface of the positive electrode can is recessed from the outer peripheral flat part may be used in combination. Also good.

<Effects of the invention> As described above, according to the cylindrical alkaline battery of this invention, it is possible to eliminate the decrease in adhesion between the positive electrode terminal and the positive electrode can at the outer periphery of the bottom of the positive electrode can, and to connect the positive electrode terminal to the bottom of the positive electrode can. The battery can be easily and reliably welded to the battery, making it easier to manufacture the battery.

[Brief explanation of the drawing]

FIG. 1A is a cross-sectional view of the positive electrode terminal used in the example,
Figure 1B is an explanatory diagram of welding this positive electrode terminal to the bottom of the positive electrode can, Figure 1C is a partial cross-sectional view of the battery of the example, and Figure 2A is an explanation of the positive electrode can used in another example. FIG. 2B is an explanatory view of welding a positive electrode terminal to the bottom surface of the positive electrode can, and FIG. 3 is an explanatory view of a conventional example. 1, 8, 10...Positive electrode terminal, 2,7,9...Positive electrode can, 3...Gel-like zinc negative electrode, 4...Positive electrode mixture,
5...Separator, 6...Adhesive label.

Claims (1)

[Claims for Utility Model Registration] 1. In a cylindrical alkaline battery in which a positive electrode terminal is integrated with the positive electrode can by welding at the outer periphery of the bottom of the positive electrode can, the positive electrode terminal has a first flat part and a bead part from the outer periphery. , the second flat part and the central protruding terminal part are sequentially formed substantially concentrically, and the second flat part is raised above the first flat part on the side opposite to the bottom surface of the positive electrode can. Characteristic cylindrical alkaline battery. 2. In a cylindrical alkaline battery in which a positive electrode terminal is integrated with the positive electrode can by welding it to the outer periphery of the bottom of the positive electrode can, the bottom surface of the positive electrode can has an outer circumferential flat part, a bead part, and a central flat part arranged in substantially concentric circles from the outer periphery. A cylindrical alkaline battery characterized in that the central flat part is recessed from the outer peripheral flat part.