JPH10312783A - Secondary battery and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a battery from being ruptured by overcharging the battery or a short circuit current and improve safety and productivity by inserting a battery cover having a terminal section into a battery can, injecting an electrolyte into the battery can from an electrolyte injection hole bored on the terminal section, and sealing the electrolyte injection hole with a foil to be cleaved when the internal pressure rises. SOLUTION: A gasket 10 is inserted into the center opening section of a battery cover 9, a terminal 8 is caulked to deform the gasket 10, and a terminal structure is formed. A positive electrode lead 7 is welded to the bottom section of the terminal 8 so that the terminal 8 serves as the counter electrode with a battery can 6. The assembled battery cover 9 is inserted into the battery can 6, the outer periphery is laser-welded, and an electrolyte is injected into the battery can 6 from an electrolyte injection hole. The gasket 10 and a foil 13 are mounted on the terminal 8, and a cover 14 is put on and caulked to integrate the terminal 8 and foil 13. An aluminum foil is used for the foil 13, for example, it is cleaved to release the internal pressure when the internal pressure rises, and it can prevent the breakage of a battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed secondary battery having an internal pressure release function and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, electronic devices such as video cameras and headphone stereos have been improved in performance and reduced in size, and a secondary battery serving as a power source for these electronic devices has been improved in heavy load characteristics and increased in energy density. The demand for is increasing.
Conventionally, lead secondary batteries and nickel cadmium secondary batteries have been used as these secondary batteries.

Further, recently, lithium metal, lithium alloy, or carbonaceous material (coke, fired organic material, etc.)
Non-aqueous electrolyte secondary batteries using a material capable of doping / dedoping lithium as a negative electrode have been actively developed.

In general, when a secondary battery has a sealed structure, if the internal pressure of the battery rises for some reason, the battery itself is relatively quickly damaged, and the battery contents are scattered around the battery. The used equipment may be damaged.

[0005] For example, the non-aqueous electrolyte secondary battery is overcharged in which a current is supplied for a longer time than usual during charging and the battery voltage is increased, or the battery is erroneously used during discharge and a failure of the equipment used. When a short-circuit state occurs in which a large current flows due to, for example, the electrolytic solution in the battery is decomposed to generate gas. When such gas gradually fills the battery and the internal pressure of the battery increases, the battery itself is damaged.

In order to prevent such damage to the battery, conventionally, for example, in a flat or rectangular battery, as shown in FIG. 4, a battery can 106 and a battery lid 102 having a terminal 101 serving as a counter electrode are provided with A safety valve 104 having an internal pressure release function is formed at a position different from the position where the terminal 101 is formed. The safety valve 104 is opened by the internal pressure of the battery to release the pressure, thereby preventing the battery from being damaged rapidly.

Further, an electrolyte injection hole 103 for injecting an electrolyte into the battery can is formed in the battery lid at a position different from the position where the terminal 101 and the safety valve 104 are formed. ing. The electrolyte injection hole 103 is sealed by a method of sealing the foil by laser welding or a method of resistance welding while press-fitting steel balls.

[0008]

However, in the above-described battery, since the electrolyte cover is provided with an electrolyte injection hole and a safety valve having an internal pressure release function, the productivity is reduced. It was low. In addition, there is a high probability that defects occur due to laser welding defects, chipping of steel balls, and the like, and productivity is low.

Accordingly, an object of the present invention is to provide a secondary battery which prevents the battery from being ruptured due to overcharging, short-circuit current, etc. of the battery, is excellent in safety and productivity, and a method of manufacturing the same. Things.

[0010]

In order to achieve the above object, a secondary battery according to the present invention has a battery can and a terminal portion which is a counter electrode, and a terminal portion is provided with an electrolyte injection hole. In addition, the electrolyte injection hole is sealed with a foil which is opened when the internal pressure rises.

Further, in the method of manufacturing a secondary battery according to the present invention, a battery cover having a terminal portion is inserted into a battery can, and an electrolyte is poured into the battery can through an electrolyte injection hole formed in the terminal portion. After the injection, the electrolyte injection hole is sealed with a foil that is opened when the internal pressure rises.

As described above, the electrolyte injection hole is provided in the terminal portion, and the electrolyte injection hole is sealed by the foil which is opened when the internal pressure rises, so that the electrolyte injection hole is used to release the internal pressure. It becomes a hole. Therefore, even when the internal pressure of the battery increases due to the overcharged state or the short-circuited state of the battery, the internal pressure is released due to the tearing of the foil and the battery is not damaged. In addition, since the electrolyte injection hole provided in the terminal portion serves as an internal pressure release hole, it is not necessary to newly provide an electrolyte injection hole and an internal pressure release hole in the battery lid. As a result, the incidence of product defects such as pre-processes such as a hole forming operation and welding defects is reduced, and productivity can be significantly improved. Further, since it is not necessary to provide a plurality of holes in the battery lid, the design when the battery is downsized becomes easy.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a secondary battery to which the present invention is applied will be described in detail with reference to the drawings.

As shown in FIG. 1, a secondary battery to which the present invention is applied has a positive electrode 1 formed by applying a positive electrode active material to a positive electrode current collector.
A negative electrode 2 formed by applying a negative electrode active material to a negative electrode current collector is laminated with a separator 3 interposed therebetween, and wound in a spiral shape. The battery 5 is housed in a battery can 6 together with the battery 5. The length and width of the spiral electrode body are adjusted in advance so that the spiral electrode body can be appropriately fitted in the battery can 6. The positive electrode 1 is electrically connected to a terminal of a battery cover described later via a positive electrode lead 7, and the negative electrode 2 and the battery can 6 are electrically connected to each other via a negative electrode lead.

A terminal 8 is provided in the opening of the battery can 6.
Is attached. The terminal 8 is connected to the positive electrode 1 via the positive electrode lead 7 and serves as a counter electrode to the battery can 6. Here, as shown in FIG. 2, the battery cover 9 has a terminal 8 at the center thereof and an electrolyte injection hole 11 penetrating the terminal 8. The terminal 8 is fixed to the battery lid 9 while maintaining insulation with the gasket 10. Electrolyte injection hole 11
The opening has gasket 12, foil 13, cover 14
And sealed. The foil 13 is, for example, an aluminum foil, and breaks when the internal pressure rises to release the internal pressure.

Specifically, a secondary battery having such a battery cover 9 is assembled as follows.

First, the above-mentioned spiral electrode body is housed in the battery can 6 together with the spring plate 5, and the negative electrode lead is connected to the battery can 6
Weld inside the opening. On the other hand, the gasket 10 is inserted into the center opening of the battery cover 9 and the terminal 8 is caulked to deform the gasket 10 to form a terminal structure. In this state, the terminal 8 is placed so that the terminal 8 is opposite to the battery can 6.
The positive electrode lead 7 is welded to the bottom of the lead. Then, the assembled battery lid 9 is inserted into the battery can 6, and the outer periphery is laser-welded. In addition, these electrical connections are not limited to welding as long as conduction and reliability are obtained, and any method may be adopted.

Next, the electrolyte injection hole 11 penetrating the terminal 8
, The electrolyte is poured into the battery can 6. After the injection, the gasket 12 and the foil 13 are placed on the terminal 8, and the terminal 8 and the foil 13 are integrated with the cover 14. Thereby, the sealed secondary battery is assembled. At this time, the foil 13 and the cover 14 may of course be integrated in advance. At this time, the foil 13 may be integrated with the terminal 8 by welding.

Also, a washer 15 may be used instead of the cover 14 shown in FIG. That is, as shown in FIG. 3, after the electrolyte is injected into the battery can 6 from the electrolyte injection hole 11 provided in the terminal 8, the gasket 12, the foil 13, and the washer 15 are placed on the terminal 8. The terminals 8 and the foils 13 may be integrated by laminating and placing in this order and caulking. In FIG. 3,
Members having the same configuration as in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

As described above, the electrolyte injection hole 11 is provided in the terminal 8 and the electrolyte injection hole 11 is sealed by the foil 13 which is torn when the internal pressure rises.
1 is a hole for releasing internal pressure. Therefore, even when the internal pressure of the battery increases due to the overcharge state or the short-circuit state of the battery, the internal pressure is released due to the tearing of the foil 13 and the battery is not damaged. At the same time, since the electrolyte injection hole 11 of the terminal 8 becomes a hole for releasing internal pressure, a hole for electrolyte injection and a hole for releasing internal pressure are newly provided in addition to the opening for providing the terminal 8 in the battery cover 9. There is no need to provide them. As a result, the rate of occurrence of product defects such as a hole forming operation and welding defects is reduced, and productivity can be significantly improved. further,
Since it is not necessary to provide a plurality of holes in the battery cover 9, designing when the battery is downsized becomes easy.

Here, actually, 3,000 secondary batteries (hereinafter referred to as Example 1) having the battery lid (terminal structure) 9 shown in FIG. 2 and the battery lid (terminal structure) shown in FIG. ) 20 secondary batteries (hereinafter referred to as Example 2)
00 pieces were produced. Then, the number of defects and the manufacturing time thereof were examined, and the production efficiency was examined. The results are shown in Tables 1 and 2.

As a comparative example, as shown in FIG.
A secondary battery (hereinafter, referred to as a comparative example) was prepared in which a terminal 101 was not provided with a hole, and a battery lid 102 was provided with a terminal 101, an electrolyte injection hole 103, and a safety valve 104 for releasing internal pressure.

Specifically, the battery of the comparative example is assembled as follows. First, the battery cover 102
After the gasket 105 is inserted into the terminal 101, the terminal 101 is swaged to form a terminal structure. Then, the terminal 10 of the electronic lid 102
1 is provided at a position different from the position where the
3 and a safety valve 104. The safety valve 104 has a thin portion provided by press working. Alternatively, a metal foil is welded to the hole. Next, after passing through such a pre-process, the battery lid 102 is inserted into the battery can 106, the outer peripheral portion is welded, and then the electrolyte is injected into the battery can 106 from the electrolyte injection hole 103, and the electrolyte is injected. The steel ball is press-fitted into the injection hole 103 and sealed by resistance welding, or the foil is pressed and laser-welded.

[0024]

[Table 1]

[0025]

[Table 2]

From the results shown in Tables 1 and 2, it can be seen that the electrolyte injection hole 11 is narrowed in the terminal 8 and the electrolyte injection hole 11 is sealed with a foil which is opened when the internal pressure rises. In the case of the secondary battery, the defective rate and the manufacturing time per unit are small, and it can be seen that the production efficiency can be greatly improved.

On the other hand, the secondary battery of the comparative example has the terminal 1
A hole for providing the safety valve 104 and the electrolyte solution injection hole 103 is required in addition to the opening for providing the safety valve 01, and press work is required to install the safety valve 104 on the battery lid 102 as a pre-process. For this reason, the secondary battery of the comparative example requires a longer manufacturing time than the battery of the example, and is inferior in production efficiency.

Therefore, the electrolyte injection hole is provided in the terminal,
It can be seen that production efficiency can be greatly improved by using the electrolyte injection hole as a hole for releasing internal pressure.

As the material of the positive electrode, the negative electrode, the non-aqueous electrolyte, the battery can, the foil and the like constituting the secondary battery according to the present invention, any conventionally known materials can be used, and there is no particular limitation. Not something. Further, the shape of the secondary battery according to the present invention is not limited to a rectangular battery, a flat battery,
The present invention is applicable to any battery such as a cylindrical battery.

[0030]

As is clear from the above description, according to the present invention, the electrolyte injection hole is provided in the terminal portion, and the electrolyte injection hole serves as a hole for releasing the internal pressure. And the production efficiency can be greatly improved. Further, the present invention is effective in reducing the size of a battery because the design is simplified.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view showing a configuration of a secondary battery to which the present invention is applied.

FIG. 2 is a cross-sectional view illustrating a configuration of a battery cover according to a first embodiment to which the present invention is applied.

FIG. 3 is a cross-sectional view illustrating a configuration of a battery lid according to a second embodiment to which the present invention is applied.

FIG. 4 is a cross-sectional view illustrating a configuration of a battery cover described as a comparative example.

[Explanation of symbols]

1 positive electrode, 2 negative electrode, 3 separator, 4 insulator, 5
Spring plate, 6 Battery can, 7 Positive lead, 8 Terminal, 9
Battery cover, 10 gasket, 11 electrolyte injection hole, 1
2 gaskets, 13 foils, 14 covers, 15 washers

Claims (2)

[Claims] An electrolyte injection hole is formed in the terminal portion, and the electrolyte injection hole is sealed with a foil that is opened when the internal pressure rises. A secondary battery characterized by the above-mentioned. 2. A battery lid having a terminal portion is inserted into a battery can, and an electrolyte is injected into the battery can from an electrolyte injection hole formed in the terminal portion. A method for manufacturing a secondary battery, wherein the secondary battery is sealed with a foil that is cleaved when the battery is raised.