JPH053710B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a bobbin type non-aqueous electrolyte battery having a structure in which a negative electrode made of a light metal such as lithium is loaded into a cylindrical positive electrode mixture via a separator. Regarding the manufacturing method.

<<Prior Art>> Conventionally, as a non-aqueous electrolyte battery, one having a bobbin-shaped structure as shown in FIG. 2 is known.

In the battery shown in FIG. 2, a power generation 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 inside a cylindrical battery case 12 that also serves as a positive terminal. A non-aqueous electrolyte 22 is injected.

The open end of the battery case 12 has a negative electrode terminal plate 26 formed in a dish shape, a thin metal plate 30 applied to the inside of the negative electrode terminal plate 26, and a synthetic resin gasket 28 fitted around these. It is sealed by. Note that the negative electrode terminal plate 26 has a cutting edge piece 2 formed by cutting and raising it with a gas vent hole 26b.
6a is provided, and the tip of this cutting blade piece 26a protrudes 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, and a current collector 24 and a lead plate 32 are bonded to the inner surface of the negative electrode 14 . The lead plate 32 electrically connects the negative electrode 14 and the negative terminal plate 26.

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.

To manufacture this type of battery, first, a cylindrical positive electrode 18 is loaded inside a battery case 12, and a separator 16 is placed inside the battery case 12.
The cylindrical negative electrode 14, which is wrapped around the outer periphery, is loaded into the cylindrical hole of the positive electrode 18. 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 14. 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 is folded inward as shown by the reference numeral 16a in the figure. By folding the lower edge 16a of the separator 16 inward and wrapping the lower end of the negative electrode 14 in this manner, the separator 16 is prevented from unrolling, the lower end of the negative electrode 14 is prevented from directly contacting the battery case 12, and internal short circuits are prevented. can be reliably prevented.

<<Problems to be Solved by the Invention>> In the above-described conventional technology, after the separator 16 is wrapped around the cylindrical negative electrode 14, the lower edge 1 of the separator 16 is wrapped around the cylindrical negative electrode 14.
The work of folding 6a inward in an orderly manner is troublesome;
This was one of the factors hindering productivity improvement.

Particularly, when the separator 16 largely protrudes from the lower end of the negative electrode 14, it becomes very troublesome to neatly fold the lower end 16a inward. Therefore, the amount of protrusion of the separator 16 cannot be increased so much.

If the amount of protrusion of the separator 16 is not large and the lower edge 16a is not properly folded inward of the negative electrode 14, it will be difficult to insert the negative electrode 14 and the separator 16 into the cylindrical hole of the positive electrode 18. The lower end edge 16a tends to slide up due to the upward tensile force acting on the separator 16, and the lower end portion of the negative electrode 14 may be exposed. This tends to cause internal short circuits, leading to the production of defective products.

For the above reasons, some attempts have been made in the past to form a separator into a bag with a bottom, insert a cylindrical negative electrode into the bag, and then insert both into a cylindrical positive electrode. .

However, in this structure and manufacturing method, the number of manufacturing steps is increased because the separator is formed into a bag shape. Also,
The insertion process consists of two steps: inserting the negative electrode into the separator, and inserting the separator and negative electrode into the positive electrode.
After all, the process becomes troublesome. Furthermore, if the size of the bag-like separator is made small in order to improve the adhesion between the negative electrode and the separator, it is difficult to insert the negative electrode, and the separator is likely to be torn during insertion.
If the adhesion between the negative electrode and the separator is not good, the electrical characteristics will deteriorate.

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 bobbin-type non-aqueous electrolyte battery having the basic structure as described above, and to It is an object of the present invention to provide a manufacturing method that prevents internal short circuits from occurring due to improper attachment of separators.

<<Means for Solving the Problem>> Therefore, in this invention, a large square separator is superimposed on the outer surface of a square negative electrode metal plate, and the left and right edges of the separator are placed on the inner surface of the negative electrode metal plate. At the same time, the lower edge of the separator that protrudes from the lower end side of the negative electrode metal plate and overlaps is fixed, and then the negative electrode metal wrapped with the separator is bent. The plate was formed into a cylindrical shape with the inner surface facing inside, and this cylindrical object was inserted into the cylindrical positive electrode.

<<Operation>> The negative electrode metal plate is completely wrapped in the separator and is formed into a cylindrical shape in that state, so the adhesion between the separator and the negative electrode is good, and a part of the separator does not shift from the negative electrode. Not at all.

<<Example>> FIGS. 1A, B, and C are process diagrams showing an example of the method for manufacturing a bobbin type nonaqueous electrolyte battery according to the present invention.

In FIG. 1, 40 indicates a rectangular negative electrode metal plate, and 50 indicates a rectangular separator having dimensions sufficiently larger than the negative electrode metal plate 40. In FIG. Negative metal plate 4
0 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 being joined to the inner surface of the coil.

The separator 50 is made of polypropylene nonwoven fabric or the like. First, as shown in FIG. 1A, the separator 50 is spread out and the negative electrode metal liquid 40 is layered thereon.
At this time, the outer surface of the negative electrode metal plate 40 when wound into a cylindrical shape is brought into contact with the separator 50 . When the separator 50 and the negative metal plate 40 are overlapped, the separator 5 protrudes from each of the four sides of the negative metal plate 40 by a predetermined amount. In particular, the length of the separator 50 is more than twice the length of the negative electrode metal plate 40.

Next, as shown in FIG. 1B, the left and right edges of the separator 50 that protrude to the left and right of the negative metal plate 40 are bent toward the inner surface of the negative metal plate 40, and the tips of both edges are overlapped with each other. Match.
Then, both ends of the stacked separators 50 are fixed by heat sealing or adhesive. The cross marked with the reference numeral 51 in the figure indicates a fixed portion.

When the left and right edges of the separator 50 are folded inward as described above, the separators 50 that have been protruding above and below the negative electrode metal plate are also stacked in two sheets. Of these upper and lower protruding parts, the two stacked parts of the separator 50 protruding toward the lower end are fixed to each other by heat sealing or adhesive. The cross marked with the reference numeral 52 in the figure indicates the fixed portion.

In the above steps, the negative electrode metal plate 40 becomes the separator 50.
It becomes completely wrapped. Next, the cylindrical negative electrode 40 covered with this separator 50 is shown in FIG.
Form into a cylindrical shape like this. For example, a cylindrical winding core is applied to the winding core in the state shown in FIG.

Through the above steps, a cylindrical negative electrode covered with a separator is completed. On the other hand, although not shown, a cylindrical positive electrode is loaded in a metal case as in the conventional case, and the cylindrical object shown in FIG. 1C is inserted into the cylindrical hole of the cylindrical positive electrode. The bobbin type non-aqueous electrolyte battery is assembled using the same process as before.

In addition, as the separator 50 in the present invention, a material obtained by stacking thin non-woven fabrics or the like as many times as necessary may be used.

<<Effects of the Invention>> As explained in detail above, according to the manufacturing method of the present invention, the work of wrapping the negative electrode metal plate with the separator is very easy, and the negative electrode metal plate is completely covered with the separator. There are no exposed or easily exposed areas. Furthermore, since the separator and the negative electrode metal plate are integrally formed into a cylindrical shape, the working process is simplified. Moreover, the adhesion between the separator and the negative electrode becomes better. That is, a bobbin type non-aqueous electrolyte battery with excellent performance and fewer internal short circuits can be manufactured with a high yield using a rational manufacturing method with better workability than conventional methods.

[Brief explanation of drawings]

FIGS. 1A, B, and C are perspective views showing the main steps of a manufacturing method according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a typical conventional structure of a bobbin type nonaqueous electrolyte battery. be. 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, 50 ... Separator, 51, 52 ... Fixing portion of separator 50.

Claims (1)

[Claims] 1. A method for manufacturing a bobbin-type non-aqueous electrolyte battery having a structure in which a cylindrical negative electrode is placed in a cylindrical hole of a cylindrical positive electrode with a separator interposed therebetween, the method comprising forming a larger square shape on the outer surface of a square negative electrode metal plate. The separators are overlapped, and the left and right edges of the separators are bent toward the inner surface of the negative electrode metal plate, and both edges are overlapped and fixed, and the overlapping separators protrude from the lower end of the negative electrode metal plate. After that, the negative electrode metal plate wrapped with the separator is formed into a cylindrical shape with the inner surface facing inside, and this cylindrical object is inserted into the cylindrical positive electrode. A method for manufacturing a bobbin type non-aqueous electrolyte battery.