JPH0374466B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a non-aqueous electrolyte battery having a structure in which a cylindrical negative electrode with a separator wrapped around its outer periphery is inserted into a hole in a cylindrical positive electrode.

As is well known, many cylindrical nonaqueous electrolyte batteries employ a so-called inside-out structure that uses a cylindrical negative electrode. A typical conventional structure of this type of non-aqueous electrolyte battery is shown in FIG. In this battery, a power generating element consisting of a cylindrical negative electrode 14, a separator 16, and a cylindrical positive electrode 18 is arranged coaxially in this order from the center in a cylindrical battery case 12 that also serves as a positive electrode terminal, and a hollow cylindrical negative electrode 14 is provided. A non-aqueous electrolyte 22 is poured into the portion 14a.
The open end of the battery case 12 is formed by a negative terminal plate 26 formed in a dish shape, a thin metal plate 30 applied to the inside of the negative terminal plate 26, and a gasket 28 fitted around these. It has been sealed. Note that the negative electrode terminal plate 26 is provided with a cutting edge piece 26a formed by cutting and raising a gas vent hole 26b, and the tip of this cutting edge piece 26a projects into the center of the thin metal plate 30. This is a burst-prevention structure that activates when the internal gas pressure of the battery increases abnormally.

The negative electrode 14 is a metal plate made of lithium or the like wound into a cylindrical shape. A current collector 24 is bonded to the inner surface of the negative electrode 14, and the current collector 24 and the metal thin plate 30 are connected by a lead plate 32. ing. The cylindrical negative electrode 14 and the negative electrode terminal plate 26 are now electrically connected. The separator 16 is made of a nonwoven fabric made of polypropylene or the like, and is wrapped around the outer periphery of the cylindrical negative electrode 14 one or more times.

The manufacturing process for this type of battery begins with the battery case 1.
A cylindrical positive electrode 18 is loaded into the inside of the positive electrode 1, and a cylindrical negative electrode 14 with a separator 16 wrapped around the outer periphery is placed inside the positive electrode 1.
This is the order in which they are loaded into holes No. 8. As shown in the figure, the width of the separator 16 is sufficiently larger than the height of the cylindrical negative electrode 14, and the separator 16 largely protrudes above and below the negative electrode 16. This is to ensure that the negative electrode 14 and the positive electrode 18 are separated from each other to prevent internal short circuits.

Conventionally, a separator 16 is placed around the outer periphery of the cylindrical negative electrode 14.
The separator 16 protruding from the lower end of the separator 16 is folded inward as shown by the reference numeral 16a in the figure. In this way, the lower edge 1 of the separator 16
By folding the separator 6a inward to wrap around the lower end of the negative electrode 14, it is possible to eliminate unwinding of the separator, prevent the lower end of the negative electrode 14 from coming into direct contact with the battery case 12, and reliably prevent internal short circuits. .

However, the separator 16 is
4 and then neatly folding the lower edge 16a toward the hollow part 14a is very troublesome.
This was one of the factors that hindered productivity. In particular, when the separator 16 largely protrudes from the lower end of the negative electrode 14, it is troublesome to neatly fold the lower end 16a. Therefore, the amount of protrusion of the separator 16 cannot be increased so much. The amount of protrusion of the separator 16 is not very large, and the lower edge 16 of the separator 16 is
If the inside of the negative electrode 14 is not properly folded, when the negative electrode 14 and the separator 16 are inserted into the hole of the cylindrical positive electrode 18, the separator 16
The lower end edge 16a tends to unravel due to the upward pulling force acting on the negative electrode 14, and the lower end portion of the negative electrode 14 may be exposed. This leads to the generation of defective products that are prone to internal short circuits.

Conventionally, in order to prevent the lower end edge 16a of the separator 16 from unraveling, the lower end edge 16a is bent inside the cylindrical negative electrode 14 and then the negative electrode 1
4 was also joined by heat fusion. According to this, from the lower end portion of the negative electrode 14 to the separator 16
Although the separator 16 will not come off and be exposed,
The heat generated when bonding the material to the negative electrode 14 becomes a problem. When heat is applied to the negative electrode 14 made of a light metal such as lithium, its surface tends to be oxidized or nitrided, resulting in a decrease in battery performance.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to improve the ease of assembly of the negative electrode and separator parts in a non-aqueous electrolyte battery having the above-mentioned structure, and to improve the ease of assembly of the separator. It is an object of the present invention to provide a manufacturing method that prevents internal short circuits from occurring due to poor mounting.

In order to achieve the above object, the present invention superimposes a larger rectangular separator on the outer surface of a rectangular negative electrode metal plate, and bends the lower edge of the separator toward the inner surface of the negative electrode metal plate. The lower end portion of the negative electrode metal plate is wrapped in the separator, and then the negative electrode metal plate is turned inside and transformed together with the separator into a cylindrical shape, and this cylindrical object is inserted into the cylindrical positive electrode hole. shall be.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 2 is a process diagram showing an embodiment of the method for manufacturing a non-aqueous electrolyte battery according to the present invention. In the figure, 40 indicates a rectangular negative electrode metal plate, and 50 indicates a rectangular separator that is sufficiently larger than the negative electrode metal plate 40. The negative electrode metal plate 40 is made of a light metal such as lithium, and is later wound into a cylindrical shape, with a lead plate 41 and a current collector 42 bonded to the inner surface of the negative electrode metal plate 40 . The separator 50 is made of polypropylene nonwoven fabric, etc.
As shown in FIG. 2, the separator 50 is spread out and the negative electrode metal plate 40 is stacked thereon. At this time, the negative electrode metal plate 4
0 is a separator 50 on the outer side when rolled into a cylindrical shape.
Apply to. When the separator 50 and the negative metal plate 40 are overlapped, the separator 50 protrudes from each of the four sides of the negative metal plate 40 by a predetermined amount.

Next, as shown in FIG. 2B, the lower edge 50a of the separator 50 that protrudes toward the lower end 40a side of the negative electrode metal plate 40 is bent upward, and the lower end 40a of the negative electrode metal plate 40 is bent upward.
The 0a portion is wrapped with this bent separator 50a.

Next, as shown in FIG. 2C, in the portions where the separator 50 protrudes from both sides of the negative electrode metal plate 40, the two separators overlapped by the bending are heat-fused and bonded. Reference numeral 51 in the figure is a heat-fused portion. What should be noted here is that the bent lower edge 50a of the separator 40 is in direct contact with the main surface of the separator 50 on both sides, and the separators are joined together by heat fusion. This means that almost no heat needs to be applied to the negative electrode metal plate 40 during heat fusion. Therefore, the surface of the negative electrode metal plate 40 is not oxidized or nitrided.

Next, as shown in FIG. 2D, these are rolled and deformed into a cylindrical shape together with the separator 50 with the negative electrode metal plate 40 inside. One slit 43 is formed on both sides of the negative electrode metal plate 40 wound into a cylindrical shape. The separators 50 protruding from both sides of the negative electrode metal plate 40 are folded into the inside of the cylinder through the slits 43 as shown in the figure. Reference numeral 50b in the figure indicates the negative electrode metal plate 40.
Both ends of the separator 50 folded into the inside of the cylinder are shown.

Through the above steps, a cylindrical negative electrode with a separator wrapped around the outer periphery is completed. On the other hand, although not shown,
As in the conventional case, a cylindrical positive electrode is loaded in a metal case, and the cylindrical object shown in FIG. 2D is inserted into the hole of the cylindrical positive electrode. The non-aqueous electrolyte battery is assembled using the same process as before.

In the manufacturing method of the present invention, before deforming the negative electrode metal plate 40 into a cylindrical shape, the negative electrode metal plate 40 is overlapped with the separator 50 in a flat plate state, the lower edge 50a of the separator 50 is folded, and the lower edge 40a of the negative electrode metal plate 40 is folded.
Wrap the part. Therefore, the lower end portion of the negative electrode metal plate 40 can be covered neatly and reliably with a very simple operation. Furthermore, if both sides of the folded separator are joined by heat fusion as in the above embodiment, the negative electrode metal plate 40 is almost completely covered by the separator, and the negative electrode metal plate 40 does not become misaligned. Therefore, even after the negative electrode metal plate 40 is deformed into a cylindrical shape as shown in FIG. Even if a tensile force is applied to the separator 50, the bent portion at the lower end of the separator 50 will not easily unravel. Therefore, the lower end of the negative electrode metal plate 40 is less likely to be exposed, and the occurrence of defective products that cause internal short circuits is extremely reduced.

Note that even if the length of the lower edge 50a of the separator 50 protruding from the lower end side of the negative electrode metal plate 40 is made sufficiently large, the workability when folding the separator 50 as shown in FIG. 2B is not impaired at all. This also ensures that the lower end portion of the negative electrode metal plate 40 is covered with the separator 50.

As explained in detail above, according to the present invention, a rational manufacturing method with better workability than before,
Non-aqueous electrolyte batteries with excellent performance and fewer internal short circuits can be manufactured with a high yield.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional typical structure of an inside-out type non-aqueous electrolyte battery, and FIG. 2 is a process diagram showing an embodiment of the method for manufacturing a non-aqueous electrolyte battery according to the present invention. . 12...Battery case, 14...Cylindrical negative electrode, 1
6...Separator, 18...Cylindrical positive electrode, 40...
... Negative electrode metal plate, 41 ... Lead plate, 42 ... Current collector, 43 ... Slit, 50 ... Separator, 5
0a...lower edge.

Claims (1)

[Claims] 1. A method for manufacturing a non-aqueous electrolyte battery having a structure in which a cylindrical negative electrode with a separator wrapped around its outer periphery is inserted into a hole in a cylindrical positive electrode, the method comprising: Larger rectangular separators are stacked one on top of the other, and the lower edge of the separator is bent toward the inner surface of the negative metal plate to wrap the lower end portion of the negative metal plate with the separator. A method for manufacturing a non-aqueous electrolyte battery, comprising deforming the separator together with the separator into a cylindrical shape, and inserting this cylindrical object into the hole of the cylindrical positive electrode. 2. The non-contact according to claim 1, characterized in that the two separators overlapped by the bending are joined by heat fusion in a portion where the separator protrudes from the negative electrode metal plate. A method for manufacturing a water electrolyte battery.