JPH1050273A - Cylindrical battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely face the inner circumferential surface of a cylindrical positive mix to the outer circumferential surface of a cylindrical negative electrode body and enhance discharge utilization factor. SOLUTION: In a battery having a cylindrical positive mix 2 arranged so that the lower end surface 2a comes in contact with the outer circumferential side inner bottom surface 1e of a cylindrical positive electrode can 1 with bottom, a cylindrical separator 3 with bottom arranged on the inside of the cylindrical positive mix 2, and a cylindrical negative electrode body 4 arranged so that the lower end surface 4b comes in contact with the inner bottom surface 3b of the separator 3, a recess 10 for accommodating the bottom 3a of the separator 3 is formed in the central part of the bottom 1d of the positive electrode can 1, and the inner bottom surface 3b of the separator 3 and the outer circumferential side inner bottom surface 1e of the positive can 1 are made flush. When the positive mix 2 is forced to the inner circumferential surface of the positive electrode can 1, the positive mix 2 is forced to the position just before the lower end surface 2a of the positive mix 2 comes into contact with the outer circumferential side inner bottom surface 1e of the positive can 1, and in this state, the upper part 1a of the positive can 1 is beaded, and thereby, the positive mix 2 is pressurized downward through a ring 20 placed on the upper end surface 2d of the positive mix 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylindrical battery and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a cylindrical battery, for example, a lithium battery having an internal structure as shown in FIG. 2 is known.
That is, in this cylindrical lithium battery, three cylindrical positive electrode mixtures 2 are fitted and inserted into a bottomed cylindrical positive electrode can 1 and stacked and loaded along the cylindrical axis direction. Each cylindrical positive electrode mixture 2 is a hollow cylindrical body formed by mixing and granulating and molding 9 parts by weight of manganese dioxide and 1 part by weight of graphite and 0.2 parts by weight of a powdery fluororesin as a binder. It is formed by pressing under pressure. A cylindrical separator 3 with a bottom made of, for example, a nonwoven fabric made of polypropylene is mounted on the inner peripheral surface of the three cylindrical positive electrode mixtures 2.
Further, a cylindrical negative electrode body 4 having a hollow inside is disposed inside the separator 3. The cylindrical negative electrode body 4 is formed by winding a lithium flat plate made of lithium metal or the like, and forming the cylindrical shape by abutting both ends of the lithium flat plate on each other. It has the same dimensions as that of the entire positive electrode mixture. One end of a strip-shaped negative electrode current collector 5 is connected to the inner peripheral surface of the cylindrical negative electrode body 4, and the other end 5 a of the negative electrode current collector 5 projects from the upper end surface of the cylindrical negative electrode body 4. ing.

A non-aqueous electrolyte 5 is injected into the inside of the positive electrode can 1 up to above the cylindrical positive electrode mixture 2 and the cylindrical negative electrode body 4. The non-aqueous electrolyte 5 is composed of, for example, a solution using lithium perchlorate as a solute and propyne carbonate and 1,2-dimethoxyethane as a solvent.

A groove 1b formed along the outer peripheral surface of the positive electrode can 1 by beading is formed in an upper portion 1a of the positive electrode can 1, and a gasket 6 is placed above the groove 1b. A sealing plate 7 having a circular outer shape and a negative electrode terminal 8 having a dish shape are sealed via the gasket 6.

At the center of the bottom 1 d of the positive electrode can 1, there is provided a bottomed cylindrical protrusion 1 c as a positive electrode terminal protruding outward, and the other end 5 a of the negative electrode current collector 5 is provided at the center opening of the gasket 6. The portion 6a is inserted and welded to the lower surface of the sealing plate 7.

In assembling a cylindrical battery having such a configuration, first, a cylindrical positive electrode mixture 2, a separator 3, and a cylindrical negative electrode body 4 are housed in a positive electrode can 1, and then a groove 1b is formed. The gasket 6 is placed in the groove 1b, and the other end 5a of the negative electrode current collector 5 is inserted through the central opening 6a of the gasket 6 to be welded to the lower surface of the sealing plate 7. After the electrolyte 5 is injected, the sealing plate 5 is connected to the opening end 1 of the positive electrode can 1 via the gasket 6 together with the negative electrode terminal 8 and the like.
a to complete the assembly.

When the cylindrical positive electrode mixture 2, the separator 3 and the cylindrical negative electrode body 4 are accommodated in the above-mentioned positive electrode can 1, the cylindrical positive electrode mixture 2 is pressed into the inside of the positive electrode can 1. By contacting the lower end surface 2a of the cylindrical positive electrode mixture 2 with the inner bottom surface 1e on the outer peripheral side of the cylindrical member 1, the cylindrical positive electrode mixture 2 is positioned in the cylindrical axis direction. Next, the separator 3 is inserted into the cylindrical positive electrode mixture 2, and the lower end surface 3 d of the bottom 3 a of the separator 3 is brought into contact with the inner bottom surface 1 e of the positive electrode can 1. Lower end face 2
The cylindrical positive electrode mixture 2 is positioned in the cylindrical axis direction such that a and 3d are flush with each other. The cylindrical negative electrode body 4 is positioned in the cylindrical axis direction by bringing the lower end surface 4b of the cylindrical negative electrode body 4 into contact with the inner bottom surface 3b of the separator 3.

As described above, the discharge reaction occurs when the cylindrical positive electrode mixture 2 and the cylindrical negative electrode body 4 disposed inside the positive electrode can 1 face each other with the separator 3 interposed therebetween. The larger the facing area between the inner peripheral surface 2b of the positive electrode mixture 2 and the outer peripheral surface 4c of the cylindrical negative electrode body 4, the greater the area effective for the discharge reaction, and the higher the discharge utilization rate.

[0009]

However, in the above-mentioned conventional battery, as shown in FIG. 2, the height of the cylindrical negative electrode body 4 with respect to the cylindrical positive electrode mixture 2 is different from that of the separator 3.
Is shifted upward by the thickness d1 of the bottom 3a. Therefore, the inner peripheral surface 2b of the cylindrical positive electrode mixture 2
And the outer peripheral surface 4c of the cylindrical negative electrode body 4 is displaced by the thickness d1 of the bottom 3a of the separator 3 and faces each other, so that a portion A having a thickness d1 from the lower end surface 2a of the cylindrical positive electrode mixture 2 and the cylinder Since there is no counterpart electrode from the upper end face 4a of the negative electrode body 4 to the part B having the thickness d1, the discharge reaction does not proceed effectively by that amount,
That is, the discharge utilization rate decreases.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to completely oppose the inner peripheral surface of a cylindrical positive electrode mixture and the outer peripheral surface of a cylindrical negative electrode body. Accordingly, it is an object of the present invention to provide a cylindrical battery capable of improving the discharge utilization rate and a method for manufacturing the same.

[0011]

In order to achieve the above object, a cylindrical battery according to the present invention has a bottomed cylindrical positive electrode can and a lower end surface in contact with the inner bottom surface on the outer peripheral side of the positive electrode can. A cylindrical positive electrode mixture disposed in a state, a bottomed cylindrical separator disposed inside the cylindrical positive electrode mixture, and a lower end face abutting on an inner bottom surface of the separator. In the cylindrical battery provided with the cylindrical negative electrode body, a concave portion for accommodating the bottom of the separator is provided in the center of the bottom of the positive electrode can, and the inner bottom surface of the separator and the outer peripheral side of the positive electrode can are provided. The bottom surface is flush.

In manufacturing the cylindrical battery having the above structure, when the cylindrical positive electrode mixture is press-fitted into the inner peripheral surface of the positive electrode can, the lower end surface of the cylindrical positive electrode mixture is formed on the outer peripheral inner bottom surface of the positive electrode can. In a state where the cylindrical positive electrode mixture is press-fitted to a position just before contacting the positive electrode can, the upper part of the positive electrode can is beaded through a ring placed on an upper end surface of the cylindrical positive electrode mixture. The cylindrical positive electrode mixture is pressed downward, and the lower end surface of the cylindrical positive electrode mixture is brought into close contact with the inner peripheral bottom surface of the positive electrode can.

According to the above-described cylindrical battery of the present invention, the concave portion provided at the center of the bottom of the positive electrode can accommodates the bottom of the separator, and the inner bottom surface of the separator and the inner bottom surface of the positive electrode can are flush with each other. Accordingly, as the lower end surfaces of the cylindrical negative electrode body and the cylindrical positive electrode mixture disposed with the separator interposed therebetween are flush, the upper end surfaces thereof are also flush.
Therefore, the outer peripheral surface of the cylindrical negative electrode body and the inner peripheral surface of the cylindrical positive electrode mixture can be completely opposed.

Further, according to the method for manufacturing a cylindrical battery of the present invention described above, when the cylindrical positive electrode mixture is pressed into the inner peripheral surface of the positive electrode can, the lower end face of the cylindrical positive electrode mixture is In a state where the cylindrical positive electrode mixture is press-fitted to a position short of contacting the inner bottom surface on the outer peripheral side of the positive electrode can, the upper portion of the positive electrode can is beaded and placed on the upper end surface of the cylindrical positive electrode mixture. The cylindrical positive electrode mixture is pressed downward through the formed ring, and the lower end surface of the cylindrical positive electrode mixture is brought into close contact with the inner bottom surface on the outer peripheral side of the positive electrode can.

That is, when the cylindrical positive electrode mixture is press-fitted into the inner peripheral surface of the positive electrode can, from when the press-fitting is started until the lower end surface of the cylindrical positive electrode mixture is brought into close contact with the inner bottom surface on the outer peripheral side of the positive electrode can. When the above operations are continuously performed at one time, when the lower end surface of the cylindrical positive electrode mixture comes into contact with the inner bottom surface on the outer peripheral side of the positive electrode can, the inside of the lower end portion of the cylindrical positive electrode mixture becomes the positive electrode can. There is a possibility that an undesired impact may be caused by contacting the corner of the concave portion provided at the center of the bottom of the battery.

However, in the method of manufacturing a cylindrical battery according to the present invention, the cylindrical positive electrode mixture is brought to a position before the lower end surface of the cylindrical positive electrode mixture comes into contact with the inner bottom surface on the outer peripheral side of the positive electrode can. Then, the press-fitting is stopped, and then the cylindrical positive electrode mixture is pressed downward via a ring by deformation of the upper portion of the positive electrode can by beading. For this reason,
When the lower end surface of the cylindrical positive electrode mixture comes into contact with the inner bottom surface on the outer peripheral side of the positive electrode can, the inner surface of the lower end portion of the cylindrical positive electrode mixture is provided at the center of the bottom of the positive electrode can. The undesired impact can be prevented by the corners of the recessed portion.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a cylindrical battery and a method for manufacturing the same according to the present invention will be described below in detail with reference to the accompanying drawings. A detailed description of the same parts as those of the conventional example shown in FIG. 2 will be omitted, and differences will be mainly described.

The first feature of the present invention, which is different from the conventional example shown in FIG. 2, is that, as shown in FIG.
A recess 10 for accommodating the bottom 3a of the separator 3
And the inner bottom surface 3b of the separator 3 is flush with the inner bottom surface 1e of the positive electrode can 1 on the outer peripheral side.

That is, the concave portion 10 provided at the center of the bottom 1d of the positive electrode can 1 is shaped so as to receive the thickness d1 of the bottom 3a of the separator 3 and to fit tightly with the bottom 3a. More specifically, the concave portion 10 is composed of a cylindrical portion 10a, an annular horizontal portion 10b, and a bottomed cylindrical protrusion 10c, and the cylindrical portion 10a has an inner diameter that can closely contact the outer peripheral surface of the bottom 3a of the separator 3. In this embodiment, the cylindrical portion 10
The inner diameter of “a” is slightly larger than the outer diameter of the bottom 3 a of the separator 3. In addition, the height d2 of the cylindrical part is
Has the same size as the thickness d1 of the bottom 3a.

The protruding portion 10c is a positive terminal similar to the conventional one, which protrudes outward from the inner peripheral end of the horizontal portion 10b.
The protrusion length d3 of the protrusion 10c from the outer peripheral side of the outer bottom surface of the positive electrode can 1 is equal to the protrusion length d of the protrusion 1c of FIG.
By setting the same size as 3, the length of the battery in the cylindrical axis direction is the same as that of the conventional battery.

Further, by increasing the length of the separator 3 in the cylindrical axis direction by the thickness d1 of the bottom, even if the bottom 3a of the separator 3 is accommodated in the concave portion 10, the upper end 3c of the separator 3 in the battery can be obtained. Is set to be the same as the conventional one.

With the above configuration, the inner bottom surface 3b of the separator 3 and the outer peripheral inner bottom surface 1e of the positive electrode can 1 are flush with each other. As a result, the lower end surfaces 2a and 4b of the entire cylindrical positive electrode mixture 2 and the cylindrical negative electrode body 4 having the same axial dimension are arranged flush with each other. The upper end surfaces 2d and 4a of the cylindrical negative electrode body 4 are also flush. Therefore, the outer peripheral surface 4c of the cylindrical negative electrode body 4 and the cylindrical positive electrode mixture 2
Can be completely opposed to the inner peripheral surface 2b over the entire length in the axial direction, and the discharge utilization ratio between the cylindrical positive electrode mixture 2 and the cylindrical negative electrode body 4 can be improved.

Next, the second feature of the present invention will be described. In the production of the above-described cylindrical battery of FIG. 1, when the cylindrical positive electrode mixture 2 is pressed into the inner peripheral surface of the positive electrode can 1, The upper portion 1a of the positive electrode can 1 is beaded and grooved in a state where the cylindrical positive electrode mixture 2 is press-fitted to a position before the lower end surface 2a of the positive electrode mixture 2 comes into contact with the inner bottom surface 1e on the outer peripheral side of the positive electrode can 1. 1b, the cylindrical positive electrode mixture 2 is formed via the ring 20 placed on the upper end surface 2d of the cylindrical positive electrode mixture.
Is pressed downward, and the lower end surface 2a of the cylindrical positive electrode mixture 2 is pressed down to and adhered to the inner peripheral bottom surface 1e of the positive electrode can 1.

The ring 20 is formed in an L-shaped cross section, and includes a horizontal annular portion 20a and a cylindrical portion 20b erected upward from the outer peripheral edge of the horizontal annular portion 20a. The length of the horizontal annular portion 20a in the radial direction is the same as that of the cylindrical positive electrode mixture, and the length of the cylindrical portion 20b in the cylindrical axis direction is obtained by beading the upper portion 1a of the positive electrode can 1. The upper end of the cylindrical portion 20b is pressed downward, and the horizontal annular portion 20b has a size suitable for pushing down the cylindrical positive electrode mixture 2 downward.

That is, when press-fitting the cylindrical positive electrode mixture 2 into the inner peripheral surface of the positive electrode can 1, the lower end surface 2 a of the cylindrical positive electrode mixture 2 comes into close contact with the outer peripheral inner bottom surface 1 e of the positive electrode can 1. In the case where the operation until the operation is performed at one time, the lower end surface 2a of the cylindrical positive electrode mixture 2 is formed on the outer side inner bottom surface 1e of the positive electrode can 1.
2c inside the lower end of the cylindrical positive electrode mixture 2
May come into contact with the corner 10d of the concave portion 10 provided in the center of the bottom 1d of the cylindrical positive electrode mixture 2, that is, the inner edge of the upper end of the cylindrical portion 10a, and may receive an undesired impact.

However, in the method of manufacturing a cylindrical battery according to the present invention, the cylindrical positive electrode mixture 2 reaches the position just before the lower end surface 2a of the cylindrical positive electrode mixture 2 comes into contact with the outer inner bottom surface 1e of the positive electrode can 1. The press-fitting is stopped in a state where the agent 2 is pressed, and thereafter, the cylindrical positive electrode mixture 2 is pressed downward through the ring 20 by the deformation of the upper portion 1a of the positive electrode can 1 by beading and slightly pressed down. Therefore, when the lower end surface 2a of the cylindrical positive electrode mixture 2 comes into contact with the outer peripheral inner bottom surface 1e of the positive electrode can 1,
Since the contact is relatively soft, the inside 2c of the lower end of the cylindrical positive electrode mixture 2 can be prevented from receiving an undesired impact by the corner 10d of the concave portion 10 provided at the center of the bottom 1d of the positive electrode can 1. It is possible to secure the reliability as a battery.

In order to confirm the improvement of the discharge utilization rate of the cylindrical battery according to the present invention described above, a discharge performance test was performed in comparison with the above-described conventional battery of FIG. As test conditions,
Common to both the product of the present invention and the conventional product, a cylindrical positive electrode mixture 2
The composition and the mixing ratio of the cylindrical negative electrode body 4 and the electrolytic solution 5 are the same as those described in the section of the prior art, and those having an outer diameter of 17.0 mm and a size of 33.5 mm in height are 3 each.
0 pieces were prepared. These were connected to 1 KΩ in an environment at a temperature of 20 ° C. to perform continuous discharge, and the duration was measured. Table 1 shows the measurement results.

[0028]

[Table 1] The average duration of the conventional product is 583 hours, while that of the product of the present invention is 618 hours. As shown in FIG. 1, it was 106, and improvement in discharge performance was recognized. Therefore, in the cylindrical battery of the present invention, the cylindrical positive electrode mixture 2 and the cylindrical negative electrode body 4
It was confirmed that the maximum effective area for the discharge reaction between the electrodes maximized the discharge utilization rate.

The cylindrical battery and the method of manufacturing the same according to the present invention are not limited to the lithium battery, but may be any other types of batteries to which the present invention can be applied, such as a cylindrical positive electrode mixture, a cylindrical negative electrode body, Regardless of the form of the material constituting the power generating element such as a liquid, the present invention can be applied to, for example, an alkaline battery.

[0030]

As described above, according to the cylindrical battery of the present invention, the inner peripheral surface of the cylindrical positive electrode mixture and the outer peripheral surface of the cylindrical negative electrode body can be completely opposed. The effective reaction area between the cylindrical negative electrode body and the cylindrical positive electrode mixture can be maximized, and the reaction utilization of the electrode can be improved.

According to the method of manufacturing a cylindrical battery according to the present invention, when the cylindrical positive electrode mixture is pressed into the inner peripheral surface of the positive electrode can, the corner of the concave portion provided at the center of the bottom of the positive electrode can is used. An undesired impact can be prevented from being given, and the reliability as a battery can be secured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the internal structure of a cylindrical battery according to the present invention.

FIG. 2 is a longitudinal sectional view showing the internal structure of a conventional cylindrical battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Positive electrode can 1a Upper part 1b Groove part 1d Bottom part 1e Outer peripheral inner bottom surface 2 Cylindrical positive electrode mixture 2a Lower end surface 2b Inner peripheral surface 3 Separator 3a Bottom portion 3b Inner bottom surface 4 Cylindrical negative electrode body 4a Upper end surface 4b Lower end surface 10 Recess 10a Cylindrical Part 10b Horizontal part 20 Ring 20a Horizontal annular part 20b Cylindrical part 20b d1 Thickness of bottom part 3a d2 Height of cylindrical part 10a d3 Projection length of protrusion 10c

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Hiroshi Hamada 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd.

Claims (2)

[Claims] 1. A positive electrode can (1) having a bottomed cylindrical shape, and a cylindrical positive electrode disposed such that a lower end surface (2a) is in contact with an inner bottom surface (1e) on an outer peripheral side of the positive electrode can (1). A mixture (2), a cylindrical separator (3) with a bottom disposed inside the cylindrical positive electrode mixture (2), and an inner bottom surface (3b) of the separator (3)
And a cylindrical negative electrode body (4) disposed with its lower end surface (4b) abutting on the bottom surface (4b) of the positive electrode can (1). A concave portion (10) for accommodating the bottom portion (3a) of (3) is provided, and the inner bottom surface (3b) of the separator (3) and the outer peripheral side inner bottom surface (1e) of the positive electrode can (1) are flush. A cylindrical battery characterized in that: 2. In the production of the cylindrical battery according to claim 1, the cylindrical positive electrode mixture (2) is press-fitted into the inner peripheral surface of the positive electrode can (1). The lower end surface (2a) of the positive electrode can (1) is the inner bottom surface (1) of the outer peripheral side of the positive electrode can (1).
e) the cylindrical positive electrode mixture (2) up to a position short of contacting with the e)
Is press-fitted, the upper part (1a) of the positive electrode can (1) is beaded through a ring (20) placed on the upper end surface (2d) of the cylindrical positive electrode mixture (2). The cylindrical positive electrode mixture (2) is pressed downward to bring the lower end surface (2a) of the cylindrical positive electrode mixture (2) into close contact with the outer peripheral inner bottom surface (1e) of the positive electrode can (1). A method for producing a cylindrical battery.