JPH11126589A - Cylindrical battery and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a cylindrical battery and a method of manufacturing the same, which can improve productivity and quality by making it possible to use a manufacturing facility in which a cylindrical battery is shared. SOLUTION: An inner diameter size (a) of a gasket 7 which has conventionally been different for each size of a cylindrical battery is made common to, for example, φ10 as shown in (b). This eliminates the need to replace the injection head even when the size of the cylindrical battery changes, thereby simplifying the setup change operation when switching between models.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical battery such as a lithium ion secondary battery and a method of manufacturing the same, and more particularly to a cylindrical battery having a different size by improving a gasket structure forming the cylindrical battery. TECHNICAL FIELD The present invention relates to a cylindrical battery and a method for manufacturing the same, which can cope with a shaped battery and can use a common production facility.

2. Description of the Related Art Recent advances in electronic technology have advanced the performance of electronic devices, and accordingly, there has been an increasing demand for cylindrical batteries used in electronic devices to have higher energy densities. Conventionally,
Secondary batteries used in these electronic devices include nickel-cadmium batteries and nickel-metal hydride batteries. These batteries have a low discharge potential and do not have a sufficient energy density, and therefore have sufficiently responded to the above requirements. There is no fact.

Recently, a lithium ion secondary battery belonging to a non-aqueous electrolyte secondary battery has come into practical use as a secondary battery satisfying these requirements. This lithium ion secondary battery has a high capacity density per volume, has a voltage three times higher than nickel cadmium batteries and nickel hydrogen batteries, and has extremely high lithium content in the battery because it exists in an ionic state. It has high security. For this reason, lithium-ion secondary batteries have been used in many fields as power sources for portable electronic devices and the like, and cylindrical batteries of various sizes have been supplied along with expansion of applications.

FIG. 1 is a perspective view showing the inside of a cylindrical lithium ion secondary battery according to the present invention. The cylindrical lithium ion secondary battery shown in the figure has a sheet shape and a positive electrode 1 having a positive electrode lead 1a, and a negative electrode 2 also having a sheet shape and a negative electrode lead 2a, for example, having a thickness of 25 μm. The spirally wound laminated electrode body is formed by being wound through a separator 3 such as a porous polypropylene film or the like, and the laminated electrode body is housed in a negative electrode can 5 via a bottom insulator 4. The wound negative electrode lead 2 a as a laminated electrode body is resistance-welded to the bottom of the negative electrode can 5.

[0005] A negative electrode can 5 containing such a laminated electrode assembly.
Then, an organic electrolyte solution in which LiPF ₆ is dissolved in a mixed solvent at a ratio of 1 mol / l is injected. After the electrolyte is injected, a gasket 7 for preventing gas leakage is pressed into the negative electrode can 5 via the top insulator 6, and the lower portion of the safety valve 8 and the positive electrode lead 1a are welded. Then, the safety valve 8 is press-fitted into the gasket 7,
Insulation washer (PTC: Positive Temperature Coeffic)
After the positive electrode lid (top cover) 10 is inserted while the negative electrode can 5 is gripped, the negative electrode can 5 is deformed and sealed in a crimping step.

In such a method for manufacturing a cylindrical lithium ion secondary battery, a groove (constriction) called beating is formed before injecting an electrolytic solution. This is for the purpose of forming a seal structure by the gasket 7, the safety valve 8, the insulating washer 9, and the positive cover 10 incorporated in the upper part of the negative electrode can 5, and to form the seal structure by rubber packing in the electrolyte injection step. . That is, in the conventional method of manufacturing a cylindrical lithium ion secondary battery, as shown in FIG. 2, the electrolyte is injected before the gasket 7 is inserted into the negative electrode can 5, so that the rubber packing 11 having a gasket function is used. Is attached to the injection head 12 and a sealing structure is formed by utilizing the "constriction" of beating to form an electrolyte injection step.

The purpose of the seal using the rubber packing 11 is the following two points. 1. At the time of injecting the electrolyte, it is necessary to make the inside of the cylinder a vacuum state and a pressurized state to exchange the air and the electrolyte inside the cylinder. 2. In order to maintain the sealing property of the gasket 7 incorporated in the upper part of the cylinder, that is, if the electrolyte adheres to the surface in contact with the gasket 7, the electrolyte crystallizes and sealing becomes difficult.
It is necessary to prevent such situations.

However, in the conventional method of manufacturing a cylindrical battery, every time the size of the cylindrical battery is changed, it is necessary to prepare a rubber packing 11 corresponding to the size and attach it to the injection head 12. . This situation not only significantly reduces the productivity of the electrolyte injection process,
There is a problem that the quality of the cylindrical battery is reduced.

Further, in the conventional method of manufacturing a cylindrical battery, the current situation is to cope with the setup change of the manufacturing equipment according to the cylindrical batteries of various sizes, and the switching loss of the manufacturing equipment is regarded as a problem. ing. Specifically, 1. Conventional cylindrical battery manufacturing facilities use a common parts feeder for various cylindrical battery components, assuming that the shape of the cylindrical battery components will change, so when switching the size of cylindrical batteries, The parts of the parts feeder need to be replaced. If there is an error in the parts replacement of the parts feeder, different kinds of parts are mixed, resulting in a reduction in the yield of the manufacturing process and a significant decrease in the reliability of the cylindrical battery. 2. The manufacturing process of the cylindrical battery includes an electrolyte injection process of injecting an organic electrolyte or the like into the assembled cylindrical battery. In the conventional electrolytic solution injection process, the injection head must be replaced each time the size of the cylindrical battery changes, and a carrier (carrying for holding the cylinder) corresponding to a different cylinder length for each size of the cylindrical battery. Tool) had to be replaced. That is, sharing injection heads provided for each size of the cylindrical battery is an important issue from the viewpoint of improving the reliability of the cylindrical battery. 3. In the above-described crimping process, a change in tooling such as replacement of parts in a parts feeder and replacement of a component positioning chuck is required along with the switching of the size of the cylindrical battery, and there is a problem that the size switching of the cylindrical battery becomes a bottleneck. .

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such a viewpoint, and it is an object of the present invention to replace the injection head in the conventional electrolyte injection process every time the size of the cylindrical battery changes. In other words, the conventional method of manufacturing cylindrical batteries is a method of switching manufacturing equipment according to various sizes of cylindrical batteries, so that problems such as a large loss of manufacturing equipment switching are solved. It is an object of the present invention to provide a cylindrical battery in which productivity and quality are improved by making it possible to use a manufacturing facility in which a cylindrical battery is shared, and a method for manufacturing the same.

[0011]

In order to solve the above-mentioned problems, a cylindrical battery according to the present invention comprises a negative electrode can having a laminated electrode body therein, a gasket, a safety valve, an insulating washer, and a gasket incorporated in the upper part of the negative electrode can. In a cylindrical battery in which a sealing structure is formed by a positive electrode lid, an inner diameter size of a gasket is common to a predetermined size regardless of an outer size of the cylindrical battery. Accordingly, the safety valve and the insulating washer that are arranged following the gasket can be shared.
As a result, manufacturing equipment such as a parts feeder for supplying these parts can be shared, and the reliability of the cylindrical battery can be improved.

Further, in the method of manufacturing a cylindrical battery according to the present invention, the laminated electrode body is provided inside the negative electrode can, and the sealing member (rubber packing) attached to the injection head is inserted into the upper portion of the negative electrode can. In the method for manufacturing a cylindrical battery in which a gasket is injected, a gasket having a common inner diameter is used instead of the rubber packing. Thus, the injection head can be shared irrespective of the external size of the cylindrical battery, and the setup change work at the time of model switching can be simplified.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a step of injecting an electrolytic solution into a cylindrical battery as shown in FIG.
The electrolyte solution is injected before assembling. At this time, a solvent-resistant rubber packing is inserted into the tip of the head by using the “constriction” formed in the beating process, and the electrolytic solution is injected while sealing using the rubber packing. However, in the conventional method of manufacturing a cylindrical battery, every time the size of the cylindrical battery is changed, it is necessary to prepare a rubber packing corresponding to the size and attach it to a large number of injection heads. The productivity in the process is significantly reduced. The present invention has been devised in view of such problems of the related art. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The same parts as those of the cylindrical battery according to the prior art are denoted by the same reference numerals.

As means for solving the above problems, the cylindrical battery of the present invention and the method of manufacturing the same have the following functions. The rubber packing attached to the injection head is eliminated, and the structure of the gasket 7 is shaped to match the tip of the injection head. Thereby, the basic design of the gasket 7 can be unified, and the design efficiency of the gasket 7 can be improved.

Function 2. Conventionally, the inner diameter size of the gasket 7 differs depending on the size of the cylindrical battery (see FIG. 3A).
, For example, as shown in FIG. This eliminates the need to replace the injection head even when the size of the cylindrical battery changes, thereby simplifying the setup change operation when switching between models. Also, by sharing the inner diameter size of the gasket 7, as shown in FIG. 4, even in a small-diameter / large-diameter cylindrical battery,
The safety valve 8 and the insulating washer (PTC) 9 connected to it can be shared. This makes it possible to use a common supply device and supply method such as a parts feeder for supplying these components. Further, on the contact surface of the upper portion of the gasket 7 with the safety valve 8 of the present invention, as shown in FIG. Thereby, the sealing performance between the gasket 7 and the safety valve 8 can be improved, and the reliability of the cylindrical battery can be improved.

Function 3. The outer shape of the positive electrode cover (top cover) 10 forming the uppermost portion of the cylindrical battery changes with the size of the cylindrical battery due to the sealing with the negative electrode can 5 in the crimping step. Are standardized to the same size as shown in FIG. Then, the contact portion of the positive electrode lid 10 with the insulating washer 9 can be shared. Further, by unifying the top portion to the same size, the positive electrode lid 10 can be supplied by the same parts feeder guide.

Function 4. As shown in FIG.
As shown in (c), for example, the ribs 20 are formed at intervals of 120 degrees on the circumference of the inner wall of the gasket 7. By lightly press-fitting the safety valve 8, the insulating washer 9, and the positive electrode cover 10 by the rib 20, these components are integrated to enable supply to a main line in a parts feeder or the like.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS By selecting the above functions and adding them to a gasket, it becomes possible to select a method of manufacturing a cylindrical battery corresponding to an existing manufacturing facility as follows. Subsequently, three specific examples of the method for manufacturing the cylindrical battery of the present invention will be described sequentially with reference to FIGS.

Embodiment 1 In the case where the above functions 1 to 3 are added to the gasket 7 of the present invention (the latter half of the cylindrical battery in FIG. 1), the gasket 7 is inserted into the negative electrode can 5 and then electrolyzed by the injection head. Inject the liquid. Then, the safety valve 8 to which the positive electrode lead 1a is welded is inserted into the negative electrode can 5, and the insulating washer 9 and the positive electrode cover 10 are sequentially press-fitted. Then, the sealing structure of the cylindrical battery is completed in a crimping step.

Embodiment 2 When the above functions 1 to 4 are added to the gasket 7 of the present invention (see FIG. 7), the gasket 7, the safety valve 8, and the insulating washer 9 are sub-assembled. The sub-assembled unit is supplied to the negative electrode can 5 into which the electrolyte has been injected, and a positive electrode lead (not shown) is welded to the safety valve 8.
The unit is pressed into the negative electrode can 5 to complete the sealing structure of the cylindrical battery in a crimping step.

Embodiment 3 When the above functions 1 to 4 are added to the gasket 7 of the present invention (see FIG. 8), the gasket 7, the safety valve 8, the insulating washer 9 and the positive electrode cover 10 are sub-assembled. The sub-assembled unit is supplied to the negative electrode can 5 into which the electrolyte has been injected, and the positive electrode lead (not shown) is welded to the safety valve 8. Then, the entire cylinder is evacuated by the external vacuum container 21 and the electrolytic solution is injected with the injection needle-like injection head 12, and then the unit is pressed into the negative electrode can 5 to complete the sealing structure of the cylindrical battery in the crimping step. Let it. in this way,
By arbitrarily changing the gasket structure of the present invention,
The degree of freedom in the method of manufacturing the cylindrical battery can be increased.

The following specific effects can be obtained by applying the cylindrical battery of the present invention and the method of manufacturing the same. First, by changing the structure of the gasket 7 as described above, it is possible to use a common injection head for the electrolytic solution, and it is possible to easily switch models in small-lot production of many kinds. For example, a model switching time, which has conventionally been several hours, can be performed in several minutes. Second, by sharing the inner diameter size of the gasket 7, the safety valve 8 and the insulating washer 9 connected to the same can be shared. As a result, it is possible to use a common supply device and supply method such as a parts feeder for supplying these components. Thirdly, since the shape of the top portion of the positive electrode lid 10 is the same regardless of the size of the cylindrical battery, a supply device and a supply method such as a parts feeder can be shared. Fourth, the production efficiency of the safety valve 8 and the insulating washer 9 is improved with the common use of the components.

Although the preferred embodiment of the present invention has been described in detail above, the present invention can be implemented in various embodiments other than this embodiment. For example, in the above-described embodiment, a cylindrical lithium ion secondary battery has been described as an example. However, the present invention is applicable to any type of battery as long as it is a cylindrical battery. Needless to say, the present invention can be applied to various manufacturing methods other than the exemplified manufacturing methods.

[0024]

According to the cylindrical battery of the present invention, a laminated structure is provided inside a negative electrode can and a seal structure is formed by a gasket, a safety valve, an insulating washer, and a positive electrode lid incorporated in an upper portion of the negative electrode can. In a cylindrical battery, the inner diameter size of the gasket is common to a predetermined size (for example, φ10) regardless of the outer size of the cylindrical battery. with this,
A safety valve and an insulating washer that are arranged following the gasket can be shared, and manufacturing equipment such as a parts feeder for supplying these parts can be shared.
It is possible to improve the reliability of the cylindrical battery.

In the method for manufacturing a cylindrical battery according to the present invention,
In the method of manufacturing a cylindrical battery in which a laminated electrode body is provided inside a negative electrode can and a sealing member (rubber packing) attached to an injection head is inserted into an upper portion of the negative electrode can to inject an electrolyte, the rubber packing is replaced. Therefore, a gasket having a common inner diameter size is used. This makes it possible to use a common injection head regardless of the external size of the cylindrical battery,
This has the effect of improving the production efficiency of cylindrical batteries.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the inside of a cell of a cylindrical lithium ion secondary battery according to the present invention.

FIG. 2 is a side sectional view illustrating a conventional electrolytic solution injection step.

FIG. 3 is a view showing a gasket structure according to the present invention, wherein (a) is a side sectional view showing a conventional gasket structure;
(B) is a side sectional view showing the gasket structure of the present invention,
(C) is a perspective view showing the gasket structure of the present invention.

FIG. 4 is a side sectional view showing a gasket peripheral structure of the cylindrical lithium ion secondary battery of the present invention.

FIG. 5 is an enlarged sectional view showing details of a portion A in FIG. 4;

FIG. 6 is a side sectional view showing a conventional positive electrode cover and a positive electrode cover of the present invention.

FIGS. 7A and 7B are process cross-sectional views illustrating a method of manufacturing the cylindrical battery of Example 2, in which FIG. 7A illustrates a gasket insertion process, FIG. 7B illustrates an electrolyte injection process, and FIG. 7C illustrates a safety valve welding process. is there.

FIGS. 8A and 8B are process cross-sectional views illustrating a method of manufacturing the cylindrical battery of Example 3, in which FIG. 8A is a diagram illustrating an electrolyte injection process, and FIG. 8B is a diagram illustrating a safety valve welding process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode, 2 ... Negative electrode, 3 ... Separator, 4 ... Bottom insulator, 5 ... Negative electrode can, 6 ... Top insulator,
7 gasket, 8 safety valve, 9 insulating washer (PT
C), 10: positive electrode lid (top cover), 11: rubber packing, 12: injection head, 20: rib, 21: external vacuum vessel, 30: annular rib

Claims (5)

[Claims] 1. A cylindrical battery in which a laminated electrode body is provided in a negative electrode can and a seal structure is formed by a gasket, a safety valve, an insulating washer, and a positive electrode lid incorporated in an upper portion of the negative electrode can. An inner diameter size is common to a predetermined size regardless of an outer size of the cylindrical battery. 2. The gasket according to claim 1, wherein an upper surface of the gasket, which is in contact with the safety valve, is formed with an annular rib having a mountain-like cross section for increasing the adhesion between the gasket and the safety valve. Cylindrical battery. 3. The gasket according to claim 1, wherein a rib is formed at a predetermined position on the inner wall of the gasket to lock the safety valve, the insulating washer, and the positive electrode lid to enable subassembly. Cylindrical battery. 4. A method for manufacturing a cylindrical battery in which a laminated electrode body is provided in a negative electrode can and a sealing member attached to an injection head is inserted into an upper portion of the negative electrode can to inject an electrolyte. A method for manufacturing a cylindrical battery, wherein the injection head is shared regardless of the outer size of the cylindrical battery by using a gasket having a common inner diameter instead of the above. 5. A rib is formed at a predetermined position on the inner wall of the gasket, and a safety valve, an insulating washer, and a positive electrode lid connected to the gasket are lightly press-fitted into the rib to be sub-assembled. The method for manufacturing a cylindrical battery according to claim 4.