JPH0456431B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Field of Industrial Application>> The present invention relates to a bobbin type nonaqueous 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>> A typical conventional structure of this type of bobbin type non-aqueous electrolyte battery is shown in FIG.

In FIG. 3, a positive electrode mixture 18 that has been press-molded into a cylindrical shape in advance is placed in close contact with the inner circumferential surface of the positive electrode can 12 in a positive electrode can 12 that is made of stainless steel or the like and is formed into a bottomed cylindrical shape. . The negative electrode 14 is formed by winding a somewhat thick lithium plate into a hollow cylindrical shape, and a separator 16 made of polypropylene nonwoven fabric is wound around the outer circumference of the negative electrode 14 . A lithium negative electrode 14 encapsulated with a separator 16 is a positive electrode mixture 1
8 , and a non-aqueous electrolyte 22 is injected into the positive electrode can 12 .

Furthermore, a lead plate 20 is crimped to the inner peripheral surface of the cylindrically wound lithium negative electrode 14 together with a current collector (not shown).

The opening of the positive electrode can 12 is closed by a dish-shaped negative electrode terminal 26 and an annular sealing gasket 28, and the inside of the battery is sealed by curling the opening edge of the positive electrode can 12. The tip of the lead plate 20 is spot-welded to the inner surface of the negative electrode terminal 26, thereby electrically connecting the lithium negative electrode 14 and the negative electrode terminal 26.

<<Problems to be Solved by the Invention>> In the conventional battery described above, the light metal such as lithium that constitutes the negative electrode 14 is very flexible;
Easily deforms plastically with a little force. Therefore, when forming the cylindrical negative electrode 14, wrapping the separator 16 around the negative electrode 14, or loading the negative electrode 14 encapsulated with the separator 16 into the positive electrode mixture 18, This tends to deform the negative electrode 14. In other words, it is difficult to incorporate the negative electrode 14 into a battery while maintaining its neat cylindrical shape.

Therefore, as shown in an exaggerated manner in FIG.
4 is easily deformed into uneven shapes. Then, the negative electrode 14
The adhesion between the separator 16 and the separator 16 or the adhesion between the separator 16 and the positive electrode mixture 18 deteriorates. This decrease in adhesion increases the internal resistance of the battery and becomes a major cause of variation in internal resistance. Even if the extreme unevenness shown in the figure does not occur, the separator 1
Simply inserting the negative electrode 14 encapsulated in the positive electrode mixture 18 into the positive electrode mixture 18 and the separator 1
6. The adhesion between the negative electrode 14 is not very good, and the performance deterioration is particularly noticeable at the end of discharge.

Another major manufacturing problem is that it is extremely troublesome to mold a light metal negative electrode into a cylindrical shape. A lithium plate is wound around a cylindrical jig to form a cylindrical shape, but at this time, the lithium plate sticks to the jig, making it impossible to easily separate the jig from the cylindrical lithium.
As a result, the above-described unevenness may occur on the negative electrode.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to facilitate forming a light metal negative electrode into a cylindrical shape, improve adhesion between power generation elements, and reduce internal resistance. An object of the present invention is to provide a method for easily manufacturing a bobbin type non-aqueous electrolyte battery with low and stable performance.

<Means for Solving the Problems> In the manufacturing method of the present invention, a strip-shaped light metal plate serving as a negative electrode is covered with a separator, and in this state, both are integrally formed into a cylindrical shape with a bottom. (referred to as the negative electrode cylinder). This negative electrode cylinder is loaded into the hollow part of the cylindrical positive electrode mixture loaded in the positive electrode can, and then a jig is inserted into the hollow part of the negative electrode cylinder, and the negative electrode cylinder is inserted into the inner peripheral surface. Push it out from the sides.

<<Function>> In the above manufacturing method, since the light metal plate is formed into a cylindrical shape while being covered with a separator,
Since the light metal plate does not come into direct contact with the jig used at that time, the jig and the light metal plate do not stick together. Moreover, the adhesion between the light metal plate and the separator in the cylindrical state is extremely good. After the negative electrode cylinder is loaded into the hollow part of the positive electrode mixture, it is spread out using a jig, so that the adhesion between the positive electrode mixture, the separator, and the light metal plate (negative electrode) is extremely good. Furthermore, since the inner circumferential surface of the cylindrical negative electrode is also covered with a separator, the jig does not come into direct contact with the negative electrode, making it easy to push and spread the negative electrode.

<<Example>> FIG. 1 shows the process of assembling a bobbin type non-aqueous electrolyte battery according to the method of the present invention, and FIG. 2 shows the battery after the assembly is completed.

First, as shown in Figure 1A, for example, a thickness of 1.8 mm,
A lithium plate 14 cut into strips with a width of 12 mm and a length of 55 mm is prepared, and appropriate arc-shaped notches 30, 30 are formed on both sides of the central part. Further, a lead plate 20 is pressure-bonded to one end side of this lithium plate 14.

Next, as shown in FIG. 1B, a rectangular separator 16 made of polypropylene is prepared, and this
The lithium plate 14 is wrapped around the lithium plate 14. The separator 16 is longer than the lithium plate 14, and both ends of the lithium plate 14 are not exposed from the separator 16.

Next, as shown in FIG. 1C, the lithium plate 14 covered with the separator 16 is formed into a cylindrical shape with a bottom. This processing can be easily performed as follows. The end face of a cylindrical rod with a diameter of about 6 mm is applied to the central part of the lithium plate 14 and separator 16 in the state shown in FIG. Draw into shape. Then, as shown in Figure C, a bottomed cylindrical negative electrode cylinder (lithium plate 14 and separator 16) having two axial slits 32 on the circumferential surface and leaving traces of the notches 30 is formed. Ru.
Note that the notches 30, 30 allow drawing processing to be easily performed without generating large wrinkles.

Further, as shown in FIG. 1D, a positive electrode mixture 18 that has been press-molded in advance into a cylindrical shape is loaded into the bottomed cylindrical positive electrode can 12 and brought into close contact with the inner circumferential surface of the positive electrode can 12. . In the hollow part of this positive electrode mixture 18,
Insert the negative electrode cylinders 14 and 16 shown in FIG. Then, a jig 34 is placed inside the hollow part of the negative electrode cylinders 14 and 16.
is inserted, and the negative electrode cylindrical bodies 14 and 16 are shaped by pushing them apart from the inner peripheral surface side.

The jig 34 is a cylindrical body having appropriate elasticity, and has a plurality of slits 36, 36, . Further, the lower end side of the inner cylindrical portion of the jig 34 is formed into a tapered hole 38, and the diameter becomes smaller toward the lower end. When the cylindrical rod 40 is inserted into the tapered hole 38, the tongue pieces divided by the slits 36, 36, . . . are pushed outward.

The outer diameter of the jig 34 is large enough to be easily inserted into the hollow portions of the negative electrode cylinders 14 and 16.
After loading this into the negative electrode cylinders 14 and 16, the cylindrical rod 40 is inserted into the tapered hole 38 and pressurized.
Then, each tongue piece of the jig 34 spreads outward and presses the inner peripheral surfaces of the negative electrode cylinders 14 and 16 in the radial direction. As a result, the negative electrode cylinders 14 and 16 are spread out to the outside, and the positive electrode mixture 18, separator 16, and lithium negative electrode 14 are brought into good contact with each other. When this pushing and spreading work is completed, the jig 34 is removed.

Note that the work of pushing apart the negative electrode cylinders 4, 16 from the inside is not limited to using the jig 34 described above, but can be performed using various types of jigs. At this time, since the lithium negative electrode 14 is not exposed on the inner peripheral surface and is covered with the separator 16, the pushing and spreading operation becomes very easy.

After the above steps, as shown in FIG.
A non-aqueous electrolyte 22 is injected into the container 2. Further, the negative electrode terminal 26, the metal sealing plate 26a, and the sealing gasket 28 are combined, and the tip of the lead plate 20 is connected to the sealing plate 26a. And negative terminal 2
6. Fit the assembly consisting of the sealing plate 26a and the sealing gasket 28 into the open end of the positive electrode can 12, and crimp the open end of the positive electrode can 16 inward to compress the sealing gasket 28. Furthermore, after that, the outer periphery of the positive electrode can 12 is covered with a heat-shrinkable resin tube 42 .

Note that the shape of the sealing gasket 28 and the sealing plate 26
Whether or not a is used or the electrical connection structure between the negative electrode terminal 26 and the lithium negative electrode 14 is not limited to the illustrated embodiment, and various implementations can be made.

Figure 4 was produced using the manufacturing method of the present invention.
This is a graph comparing the discharge performance of a CR2/3 6 L-type lithium battery and a conventional lithium battery of the same type and structure shown in FIG. 3. The discharge conditions were 1KΩ continuous discharge, and measurements were made under both temperature conditions of 20°C and -10°C. The solid line is the characteristic of the battery to which the present invention is applied, and the dotted line is the characteristic of the conventional battery. As is clear from the figure, the performance of the battery to which the present invention is applied is improved by more than 30% compared to the conventional battery. This is due to the good adhesion between the power generation elements, resulting in low internal resistance and improved low-temperature performance.

<<Effects of the Invention>> As explained in detail above, according to the method for manufacturing a bobbin type non-aqueous electrolyte battery according to the present invention, it is very easy to form a cylindrical negative electrode from a light metal, and the positive electrode assembly is The adhesion between the agent, separator, and negative electrode is improved, and battery performance is improved.

[Brief explanation of the drawing]

Fig. 1 is a process diagram showing an example of the manufacturing method of the present invention, Fig. 2 is a cross-sectional view of a battery completed by the same method, and Fig. 3 shows the structure of a conventional bobbin type non-aqueous electrolyte battery. The cross-sectional view shown in FIG. 4 is a discharge characteristic diagram comparing the performance of a conventional battery and a battery according to the present invention. 12... Positive electrode can, 14... Negative electrode (light metal plate), 16
...Separator, 18...Positive electrode mixture, 34...Jig.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a bobbin type non-aqueous electrolyte battery, which includes the following steps a to e. a...Step of loading a cylindrical positive electrode mixture into a cylindrical positive electrode can with a bottom in close contact with the inner peripheral surface of the positive electrode can, b...Step of enclosing a strip-shaped light metal plate that will become the negative electrode with a separator, c. ...Step of integrally forming the light metal plate and separator after step b into a negative electrode cylinder having a cylindrical shape with a bottom, d... Loading the negative electrode cylinder after step c into the hollow part of the positive electrode mixture after step a. Step e... A step of inserting a jig into the hollow part of the negative electrode cylinder after step d and pushing the negative electrode cylinder outward from the inner peripheral surface side.