JPH0537410Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention relates to a cylindrical lithium battery, and in particular to a structure that prevents a shoot caused by a negative electrode lead plate protruding from a separator coming into contact with a mixture side.

<<Prior art>> A cylindrical lithium battery has a positive electrode mixture and lithium layered on the front and back sides of a separator, which is wound, and this wound element is housed in a case. The positive and negative lead plates protruding from each other are bent and connected to the positive and negative terminals of the case.

More specifically, when the separator is wound, the mixture is on the inside and the lithium is on the outside.
The negative electrode lead plate is arranged so as to protrude above the outer peripheral side of the separator, and the winding end face is housed in the inner bottom face of the case with the end face covered with an insulator.

When housed in the cylindrical case, the negative electrode lead plate is bent and connected to the inner bottom surface of the case.

[Problem that the invention aims to solve] The drawback of the above structure is that the negative electrode lead plate does not necessarily bend properly when it is stored in the case, and if it is not bent properly, the winding will be difficult after winding. If the positive electrode mixture protrudes from the separator due to misalignment or the like and is exposed, the negative electrode lead plate comes into contact with this portion, causing an internal short circuit.

Conventionally, as a countermeasure against this problem, an additional step has been taken to affix an insulating seal to the base of the end of the negative electrode lead plate protruding from the separator.

However, as is well known, metallic lithium changes into hydroxide when it comes into contact with moisture in the air.
In order to apply the sticker later, the operator must put his/her hand into the dry room through gloves to apply the sticker while the winding element is housed in the dry room, which is an extremely troublesome process. It was hot.

Further, even when an insulating sticker is pasted in advance in the previous step, an extra step is performed as a sticker pasting step, and dehydration treatment is also required afterward, resulting in a decrease in work efficiency.

This idea was made in view of the above problems, and its purpose is to prevent internal short circuits caused by the negative electrode lead plate, and to eliminate the troublesome work of pasting stickers. The present invention provides a cylindrical lithium battery as described above.

《Means for solving the problem》 In order to achieve the above object, this invention laminates a positive electrode mixture and negative electrode lithium on the front and back sides of a separator, and winds the separator with the positive electrode mixture on the inside. In a cylindrical lithium battery in which an element is housed in a cylindrical case, and positive and negative electrode lead plates located on the front and back sides of the separator and projecting upward and downward are connected to the positive and negative electrode terminals of the case in a bent state. The gist of the present invention is that the protruding portion of the negative electrode lead plate of the separator is formed to have a wider width than other portions.

<<Operation>> According to the above configuration, when the negative electrode lead plate is bent, it is bent with the wide portion of the separator in contact with the inside, and the bent portion is isolated from the positive electrode mixture side by the separator.

<<Example>> Hereinafter, an example of this invention will be described in detail using the drawings.

In Figures 1 and 2, 1 is a separator, 2
3 is a positive electrode mixture located on the surface of the separator 1, and 3 is metal lithium as a negative electrode attached to the back surface of the separator 1.

The positive electrode mixture 2 is placed in the center of the surface of the separator 1.
A positive electrode lead plate 4 is laminated by spot welding to the central metal surface of the thin metal plate interposed therein, and its lower end protrudes from the lower edge of the separator 1.

Further, a negative electrode lead plate 5 made of a thin metal plate and having one end in contact with the lithium 3 is arranged near the end of the winding on the back side of the separator 1.

The negative electrode lead plate 5 is composed of a substrate portion 5a that contacts the lithium 3 and a lead plate portion 5b extending upward from the upper edge of one end of the substrate portion. It is made to protrude upward from the upper edge.

Then, a wide portion 6 that is wider than other portions is formed upright at a portion near the protruding portion of the lead plate portion 5b of the separator 1, and this wide portion 6 is formed at the end portion B of the winding of the separator 1 ( (appears on the right side in the figure) with a constant width.

In the above configuration, the separator 1 is sequentially wound from the winding start end A (appears on the left side in the figure) with the positive electrode mixture 2 side facing inside and the lithium 3 side facing outside, as shown in FIG. It is formed into a cylindrical winding element 7. The positive electrode lead plate 4 protrudes from the lower part thereof, and the lead plate portion 5b of the negative electrode lead plate 5 protrudes from the upper outer peripheral side. The wide portion 6 is located on the inner peripheral side of the protruding base of the lead plate portion 5b, and the wide portion 6 is also located on the outer peripheral side.

In this state, an insulating plate 8 is arranged on the upper surface of the winding element 7, and the lead plate part 5b is turned slightly inward and housed upside down in a cylindrical case 9 with a bottom. When the winding element 7 is further pushed in from the state where the lead plate portion 5b is in contact with the inner bottom surface of the case 9, the lead plate portion 5b is bent from its base and comes into contact with the inner bottom surface of the case 9, as shown in FIG. do. In this state, the bent base 5 of the lead plate portion 5b
b-1 is bent inward together with the wide portion 6, and is in a bent state with the wide portion 6 interposed between it and the end surface of the winding element 7. Thereafter, the tip of the lead plate portion 5b is spot welded to the inner bottom surface of the case 9 to complete the connection.

Therefore, depending on the state of loading into the case 9, for example, the lead plate portion 5b may not be in the normal bent state, and even if it takes various bending forms, the wide portion 6 will always be present inside the bent portion. is,
This maintains the insulation properties of this part.

<<Effects>> As explained in detail in the examples above, in the case of the cylindrical lithium battery according to this invention, when the negative electrode lead plate is bent, the wide part of the separator is pressed against the inside, and the negative electrode lead plate is bent. Since the bent part is isolated from the positive electrode mixture side by a separator, insulation properties can be maintained reliably without the need for the troublesome work of pasting stickers.
Internal short circuits caused by the negative electrode lead plate can be prevented.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the winding element of the lithium battery according to this invention in the unfolded state, Fig. 2 is a side view of the winding element in the unfolded state, and Fig. 3 is the winding state of the winding element. FIG. 4 is a partially sectional view showing the winding element loaded in the case. DESCRIPTION OF SYMBOLS 1... Separator, 2... Positive electrode mixture, 3... Metal lithium, 4... Positive electrode lead plate, 5... Negative electrode lead plate, 5a... Substrate, 5b... Lead plate part, 5
b-1...Bent base, 6...Wide portion, 7...Wound element, 8...Insulating plate, 9...Cylindrical case.

Claims (1)

[Claims for Utility Model Registration] A positive electrode mixture and negative electrode lithium are laminated on the front and back sides of a separator, and the positive electrode mixture is wound on the inside,
This winding element is housed in a cylindrical case, and the positive and negative electrode lead plates, which are located on the front and back sides of the separator and project upward and downward, are bent and connected to the positive and negative electrode terminals of the case. A cylindrical lithium battery, characterized in that a protruding portion of the negative electrode lead plate of the separator is formed to have a wider width than other portions.