JPH041648Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention consists of a bottomed cylindrical metal battery case and a strip-shaped positive electrode, separator, and negative electrode that are alternately stacked and wound into a spiral shape. an insulating cover interposed between the bottom surface of the wound electrode group and the bottom inner surface of the battery case, one end of which is connected to one electrode of the wound electrode group; The present invention relates to a cylindrical battery having a lead plate whose other end is welded to the bottom inner surface of the battery case.

<<Prior Art>> A typical structure of the above-mentioned type of cylindrical battery is shown in FIGS. 3 and 4. This battery consists of a cylindrical metal battery case 1 with a bottom, a wound electrode group 2 housed in the battery case 1, a positive terminal plate 3 which also serves as a lid of the battery case 1, and a sealing gasket 4. It mainly consists of

The wound electrode group 2 is formed by winding a separator 5, a positive electrode 6, and a negative electrode 7, each of which is formed into a band shape, in a spiral shape by overlapping each other alternately. It is stored with a . The negative electrode 7 is, for example, a lithium metal ribbon crimped onto a stainless steel strip. The positive electrode 6 has a thin layer of positive electrode mixture held on both sides of a band-shaped current collector as a core material. This is a so-called lithium battery, and a non-aqueous electrolyte is injected into the battery case 1.

One end of a positive lead plate 10 is connected to the positive electrode 6 from the center of the upper end of the wound electrode group 2, and the other end of this lead plate 10 is connected to the inner surface of the positive terminal plate 3.

One end of a negative electrode lead plate 11 is connected to the negative electrode 7 near the lower end of the wound electrode group 2 , and this lead plate 11 is connected to the center of the bottom inner surface of the battery case 1 . 11a is a welding nugget between the battery case 1 and the lead plate 11.

FIG. 4 shows the relationship between the wound electrode group 2, the insulating sheet 8, and the negative lead plate 11. The insulating sheet 8 is made of a relatively flexible plastic sheet and has a circular shape with approximately the same outer diameter as the wound electrode group 2, and has a hole 8a in the center, which is used as follows.
is provided.

This battery is assembled in the following steps. The negative electrode lead plate 11 is connected to the negative electrode 7 of the wound electrode group 2 in advance. The insulating sheet 8 is applied to the bottom surface of the wound electrode group 2, the negative electrode lead plate 11 is brought out to the side once, and then bent toward the bottom surface of the insulating sheet 8.
The tip of the lead plate 11 is positioned directly below the central hole 8a. In this state, the insulating sheet 8 and the wound electrode group 2 are inserted into the battery case 1.

Once the wound electrode group 2 is properly housed, a thin welding electrode rod is inserted into the center of the spiral wound electrode group 2. Then, the tip of the welding electrode rod passes through the hole 8a of the insulating sheet 8 and comes into contact with the negative electrode lead plate 11. The negative electrode lead plate 11 and the battery case 1 are spot welded using this welding electrode rod.

<<Problems to be solved by the invention>> In the conventional cylindrical battery described above, the insulating sheet 8
When inserting the wound electrode group 2 into the battery case 1, there was a problem in that the insulating sheet 8 was easily misaligned.

The circular insulating sheet 8 is a cylindrical wound electrode group 2
The correct position is to place the insulating sheet 8 concentrically on the bottom of the battery case 1, but since the insulating sheet 8 is a relatively flexible plastic sheet, it is not easy to set it in the battery case 1 in such a correct position. . This assembly work must be done very carefully.

If the insulating sheet 8 is displaced from the correct position, it will not be possible to insulate between the lower end surface of the wound electrode group 2, the bottom inner surface of the battery case 1, and the negative electrode lead plate 11 as expected, and the positive electrode 6 will be Alternatively, it may come into contact with the negative electrode lead plate 11, causing an internal short circuit.

This idea was devised in view of the above-mentioned conventional problems, and was designed to make the battery assembly process easier.
Moreover, it is an object of the present invention to provide a cylindrical battery in which the lower part of the wound electrode group is reliably insulated from the battery case and the lead plate.

[Means for solving the problem] Therefore, in this invention, instead of the circular insulating sheet, a bottomed cylindrical insulating cover that covers the bottom and the lower outer periphery of the wound electrode group is used. A lead plate connected to an electrode near the bottom of the battery case was drawn out to the lower surface side through a small hole formed in the insulating cover, and the tip of the lead plate was welded to the inner surface of the bottom of the battery case.

<<Operation>> A bottomed cylindrical insulating cover is placed over the lower end of the wound electrode group, and the lead plate is drawn out from the lower end of the wound electrode group through the small hole and toward the lower surface. Therefore, there is no possibility of the insulating cover being misaligned with respect to the wound electrode group. Therefore, the insulating cover reliably insulates and separates the wound electrode group from the battery case and lead plate.

<<Example>> Figs. 1 and 2 show a cylindrical battery according to an embodiment of this invention. In FIG. 1, the relationship between a bottomed cylindrical battery case 1, a positive terminal plate 3 and a sealing gasket 4 that close the opening of the battery case 1 is the same as in the conventional example shown in FIG. In addition, a wound electrode group 2 is formed by alternately stacking a band-shaped positive electrode 6, a separator 5, and a negative electrode 7 and winding them in a spiral shape.
It is also the same as in Fig. 3. Furthermore, the configuration in which the positive electrode 6 and the positive terminal plate 3 are connected by the positive electrode lead plate 10 is also the same as that shown in FIG.

In the battery according to this invention, the bottom and lower outer periphery of the wound electrode group 2 are covered with a bottomed cylindrical insulating cover 20 placed thereon. Insulation cover 2
0 is made of polypropylene or the like, and is formed into a thin cylindrical shape with a bottom. This insulation cover 20
A hole 20a is formed in the center of the bottom surface for passing the aforementioned welding electrode rod therethrough, and a small hole 20b for passing the negative electrode lead plate 11 is formed near the periphery of the bottom surface.

As shown in FIG. 2, an insulating cover 20 is placed over the lower part of the wound electrode group 2 to which the negative electrode lead plate 11 is connected.
b, bend the lead plate 11 horizontally, and position the tip directly under the central hole 20a. In this state, the wound electrode group 2 is inserted into the battery case 1. At this time, without being particularly careful,
Since the insulating cover 20 itself is properly attached to the lower part of the wound electrode group 2, unless the insulating cover 20 is intentionally shifted, it will fit inside the battery case 1 in the correct installed state.

The negative electrode lead plate 11 and the battery case 1 are welded in the same way as before, and the welding electrode rod is connected to the wound electrode group 2.
is inserted through the center hole, and its tip is brought into contact with the negative electrode lead plate 11 through the hole 20a. Spot welding is performed in this state.

<<Effects of the invention>> As explained in detail above, in the cylindrical battery according to the invention, the bottomed cylindrical insulating cover is placed over the lower part of the wound electrode group, and the battery is housed in the battery case. At the same time, since the lead plate is pulled out from the small hole formed in this cover, the insulating cover can be set in the battery case in the correct position without any careful assembly work, and the desired winding shape can be achieved. Ensures insulation and separation between the electrode group and the inner bottom surface of the battery case. Therefore, internal short circuits due to poor insulation do not occur, and assembly workability is improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a cylindrical battery according to an embodiment of the invention, FIG. 2 is a perspective view showing the relationship between the wound electrode group 2 and the insulating cover 20 in FIG. 1, and FIG. 4 is a sectional view showing the structure of a conventional cylindrical battery, and FIG. 4 is a perspective view showing the relationship between the wound electrode group 2 and the insulating sheet 8 in the battery of FIG. 1...Battery case, 2...Wound electrode group, 3...
...Positive terminal plate, 4... Sealing gasket, 5... Separator, 6... Positive electrode, 7... Negative electrode, 8... Insulating sheet, 9... Non-aqueous electrolyte, 10... Positive electrode lead plate, 11... Negative electrode lead plate, 11a... Welding nugget, 20... Insulating cover, 20a... Hole, 20
b...Small hole.

Claims (1)

[Scope of utility model registration request] A metal battery case 1 having a cylindrical shape with a bottom, a wound electrode group 2 in which a positive electrode 6, a separator 5, and a negative electrode 7 each having a strip shape are alternately stacked and wound in a spiral shape, and this wound electrode an insulating cover 2 interposed between the bottom of the group and the inner surface of the bottom of the battery case;
0 and a lead plate 11 having one end connected to one electrode of the wound electrode group and the other end welded to the bottom inner surface of the battery case, the insulating cover 20 is connected to the winding electrode group. Rotary electrode group 2
The lead plate 11 is formed into a cylindrical shape with a bottom and has a small hole 20b on the bottom surface, and the other end of the lead plate 11 passes through the small hole to the bottom side of the insulating cover 20. A cylindrical battery characterized in that it is pulled out and welded to the bottom inner surface of the battery case 1.