JP2010080140A - Sealed battery and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed battery that is weld-sealed by laser processing without a sealing plug fit into a liquid pouring hole and without laser light entering the can to damage a battery element, and to provide a method of manufacturing the same. <P>SOLUTION: An electrolyte pouring hole 7 for pouring in an electrolyte is formed in the middle part of a lid 2 for sealing an opening of a battery can 5. The electrolyte pouring hole 7 penetrates the lid 2 in a tilted manner with respect to the surface of the lid. The electrolyte is poured in and then the electrolyte pouring hole 7 is welded by laser processing and is sealed thereby. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealed battery for sealing an electrolyte solution injection hole after injecting an electrolyte solution, and a method for manufacturing the same.

  Portable electronic devices are becoming smaller and lighter and have advanced functions. As a result, batteries for power supplies used in these electronic devices are required to be small, lightweight, and have a large capacity per volume. Lithium ion batteries using positive electrode active materials and negative electrode active materials doped and dedoped with lithium ions have a higher energy density per volume or mass than conventional nickel cadmium batteries and lead batteries. As a secondary battery, it is used as a power source for small electronic devices.

  In a lithium ion battery, a battery element in which a positive electrode and a negative electrode are wound through a separator or a stacked battery element is stored in a metal battery outer container. After attaching a lid body having an electrode insulated by an insulating member and having a polarity different from that of the battery outer container and sealing the fitting portion with the battery outer container, a predetermined amount of electrolytic solution is supplied from the electrolyte injection hole. The electrolyte injection hole is fitted with a sealing plug and welded by laser welding or the like to seal the injection hole.

  4A and 4B are diagrams for explaining a conventional sealed battery. FIG. 4A is a plan view of the sealed battery, FIG. 4B is a cross-sectional view of the sealing plug, and FIG. 4C is FIG. FIG. 4A is a cross-sectional view illustrating a sealed state in which a sealing plug is inserted into FIG. 4C.

  The electrolytic solution is injected from the electrolytic solution injection hole 7, the sealing plug 1 is attached to the injection hole 7 provided with the step 4 of the lid 2, and the outer periphery of the sealing plug 1 is welded and sealed by laser processing. It has stopped.

  In the production of a sealed battery, it is indispensable to attach a sealing plug in order to seal the liquid injection hole of the lid of the sealed battery into which an electrolytic solution has been injected. Further, if the sealing plug is not accurately attached to the liquid injection hole, the sealing may be poor. Therefore, methods such as temporarily fixing the sealing plug or adjusting the irradiation direction of the laser irradiated at the time of sealing have been proposed. Sealed batteries are sealed using the sealing plug. Is.

  On the other hand, in patent document 1, after sealing in the state which formed the gap part in the part of the meeting part of the circumference | surroundings of a cover body and the opening part of a battery can, a gap | interval part after inject | pouring electrolyte solution from a gap | interval part. A sealed battery with a sealed plug has been proposed. That is, a sealed battery that seals a battery can without using a sealing plug has been proposed, which eliminates the need for a process related to the sealing plug and reduces the manufacturing cost.

JP 2002-1000032 A

  However, in Patent Document 1, in the gap portion at the part of the meeting portion between the periphery of the lid and the opening of the battery can, the electrolyte oozes out to the weld portion of the gap portion due to surface tension and is locally welded. There is a risk that unsuccessful sealing will occur.

  That is, since a part of the periphery of the lid in the gap is in contact with the inner wall of the battery can, when the amount of the electrolyte is large, the electrolyte is welded in the thickness direction of the lid or the battery can. There is a possibility of oozing out to the welded portion of the gap through the inner wall.

  Further, since the gap portion is provided vertically, there is a possibility that the laser beam may enter the inside of the can and damage the battery element when the gap portion is welded.

  That is, the technical problem of the present invention is that a sealing plug is not used for the electrolyte injection hole, and welding sealing can be performed by laser processing without damaging the battery element due to laser light entering the inside of the can. The present invention provides a sealed battery and a manufacturing method thereof.

  The sealed battery of the present invention is a sealed battery in which a lid is placed and sealed in the opening of the battery can, and the lid is sealed at the center of the lid that seals the opening of the battery can. In contrast, the electrolyte injection hole provided at an inclination is weld-sealed by laser processing.

  The method for manufacturing a sealed battery according to the present invention is a method for manufacturing a sealed battery in which a lid is placed and sealed in an opening of the battery can, and after the battery element is housed in the battery can, the battery Electrolyte is injected from the electrolyte injection hole provided at the center of the lid that seals the opening of the can at an angle with respect to the surface of the lid, and then the injection hole is laser processed. It is characterized by welding sealing.

  According to the present invention, a hermetically sealed type that does not use a sealing plug in the electrolyte injection hole and enables laser welding without laser beam entering the can and damaging the battery element. A battery and a manufacturing method thereof are obtained.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram for explaining a sealed battery according to the present invention. FIG. 1A is a perspective view of the sealed battery, FIG. 1B is a plan view of the sealed battery, and FIG. (B) AA sectional drawing, FIG.1 (d) is sectional drawing explaining the sealing state of FIG.1 (c).

  In the sealed battery of the present invention, the battery element is housed inside the battery can 5 and then the opening of the battery can 5 is sealed with the lid 2. The lid 2 has the electrode terminal 6 at the center. And one electrolyte injection hole 7.

  The electrolytic solution is injected from the electrolytic solution injection hole 7 and then welded by laser processing to seal the injection hole 7 to manufacture a sealed battery.

  The electrolyte injection hole is formed so as to be inclined at an angle that cannot be seen through when the plate-like lid is viewed from the vertical direction. It is not necessary that the liquid injection hole is formed in an inclined manner, and when the laser beam is irradiated from the vertical direction, the liquid injection hole should not be seen through when the lid is viewed from the vertical direction. That's fine. The angle for forming the liquid injection hole linearly varies depending on the relationship between the thickness of the lid and the diameter of the liquid injection hole, but is 30 ° or more and 60 ° or less with respect to the surface of the lid. preferable. The injection hole is preferably formed by press working or the like.

  By directly irradiating the injection hole with laser from the vertical direction, the injection hole is welded and sealed by melting a part of the lid without using a sealing plug and entering the inside of the can. I can do it. Since the laser beam does not enter the inside of the can, the battery element housed in the battery can is not damaged.

  Even if the direction of laser light irradiation is not vertical, the injection hole shape is such that the laser light does not damage battery elements inside the battery can in the positional relationship between the laser light irradiation direction and the liquid injection hole. Good.

  2A and 2B are diagrams for explaining another liquid injection hole of the sealed battery of the present invention. FIG. 2A is a plan view of the sealed battery, and FIG. 2B is AA of FIG. Sectional drawing and FIG.2 (c) are sectional drawings explaining the sealing state of FIG.2 (b).

  There are a plurality of electrolyte injection holes 7 instead of one. By injecting the electrolytic solution from the electrolytic solution injection hole 7 and then performing welding by laser processing, all the injection holes 7 are sealed to manufacture a sealed battery.

  As long as the lid is not seen through when viewed from the vertical direction, a plurality of liquid injection holes may be provided. When injecting an electrolytic solution, the number of injection holes is large, so that the electrolytic solution can be easily injected, the injection time can be shortened, and productivity can be improved.

  FIG. 3 is a view for explaining another liquid injection hole of the sealed battery of the present invention, FIG. 3 (a) is a plan view of the sealed battery, and FIG. 3 (b) is an A- FIG. 3A is a cross-sectional view illustrating the sealed state of FIG. 3B.

  The electrolyte injection hole 7 has a rectangular parallelepiped shape rather than a cylindrical shape. The electrolytic solution is injected from the electrolytic solution injection hole 7 and then welded by laser processing to seal the injection hole 7 to manufacture a sealed battery.

  The shape of the liquid injection hole may be any shape as long as the lid is not seen through when viewed from the vertical direction. When the electrolyte is injected through a round tube, the corners around the rectangular parallelepiped injection hole serve to exhaust the air in the battery can, reducing the injection time and increasing productivity. Can be improved.

  Examples of the present invention are described in detail below.

Example 1
A sealed battery will be described as Example 1 of the present invention with reference to FIG. The battery element was housed in a battery can 5 made of an aluminum alloy (A3003) having a width of 30 mm, a height of 48 mm, and a thickness of 4 mm. Thereafter, the lid body 2 made of aluminum alloy (A3003) having a diameter of 0.3 mm and having a liquid injection hole 7 inclined through the surface of the lid body 2 with an inclination of 40 degrees is fitted into the battery can 5. And then welded. The electrolyte was injected from the injection hole 7 and welded and sealed by laser processing to produce a lithium ion battery.

For the positive electrode, LiCoO _{2 as} a positive electrode active material, a conductive additive and a binder are mixed and dispersed in N-methyl-2-pyrrolidone (hereinafter referred to as NMP), and a slurry is applied on both sides of an aluminum foil Made by drying.

  The negative electrode is made by mixing and dispersing carbon, which is a negative electrode active material capable of intercalating and deintercalating Li ions, a conductive additive and a binder in NMP, applying a slurry to both sides of the copper foil, and drying. did.

  The electrode width was slit so that the width of the negative electrode current collector was about 2 mm wider than the width of the positive electrode current collector. A positive electrode and a negative electrode were wound through a separator to produce a battery element.

  The electrolytic solution used was lithium hexafluorophosphate as an electrolyte and dissolved in a mixed solvent of diethyl carbonate (DEC) and ethylene carbonate (EC). After injecting the electrolyte from the injection hole, the injection hole was irradiated with a laser having a laser beam diameter of Φ0.6 mm from the vertical direction and sealed by welding.

  About the produced 500 lithium ion battery, when the sealing state after welding was confirmed by laser processing, there was no generation | occurrence | production of a defect. Further, the battery can was disassembled and the battery element was confirmed, but there was no damage by the laser beam.

(Example 2)
A lithium ion battery was produced in the same manner as in Example 1 except that the lid structure had three injection holes. As shown in FIG. 2, a lid 2 made of an aluminum alloy (A3003) having a diameter of 0.3 mm and having three injection holes 7 penetrating through the surface of the lid 2 at an inclination of 40 degrees and having a thickness of 1 mm. Was fitted into a battery can and welded. An electrolyte was injected from the injection hole 7 and welded and sealed by laser processing to produce a lithium ion battery.

  About the produced 500 lithium ion battery, when the sealing state after welding was confirmed by laser processing, there was no generation | occurrence | production of a defect. Further, the battery can was disassembled and the battery element was confirmed, but there was no damage by the laser beam.

(Example 3)
A lithium ion battery was produced in the same manner as in Example 1 except that the injection hole was a rectangular parallelepiped in the structure of the lid. As shown in FIG. 3, a lid made of aluminum alloy (A3003) having a thickness of 2 mm, a width of 0.3 mm, and a thickness of 1 mm provided with a liquid injection hole 7 that is inclined by 40 degrees with respect to the surface of the lid 2 The body 2 was fitted into a battery can and welded. An electrolyte was injected from the injection hole 7 and welded and sealed by laser processing to produce a lithium ion battery.

  About the produced 500 lithium ion battery, when the sealing state after welding was confirmed by laser processing, there was no generation | occurrence | production of a defect. Further, the battery can was disassembled and the battery element was confirmed, but there was no damage by the laser beam.

(Comparative Example 1)
A lithium ion battery was produced in the same manner as in Example 1 except that the injection hole was provided perpendicularly with an inclination of 90 degrees with respect to the surface of the lid in the lid structure.

  FIG. 5 is a diagram for explaining a sealed battery in which liquid injection holes are provided vertically and does not use a sealing plug. FIG. 5 (a) is a plan view of the sealed battery, and FIG. 5 (b) is a diagram of FIG. ) Of FIG. 5A is a cross-sectional view, and FIG. 5C is a cross-sectional view illustrating the sealed state of FIG. A lid 2 made of aluminum alloy (A3003) having a diameter of 0.3 mm and a thickness of 1 mm provided with a liquid injection hole 7 inclined vertically by 90 degrees with respect to the surface of the lid 2 is fitted into the battery can. Welded. An electrolyte was injected from the injection hole 7 and welded and sealed by laser processing to produce a lithium ion battery.

  About ten produced lithium ion batteries, when the sealing state after welding was confirmed by laser processing, ten welding defects by a pinhole generate | occur | produced. The laser beam entered the inside of the can and the electrolyte was rapidly gasified and ejected from the injection hole, resulting in a failure to seal itself. Further, when the battery can was disassembled and the battery element was confirmed, ten damages due to the laser beam occurred.

(Comparative Example 2)
A lithium ion battery was produced in the same manner as in Example 1 except that the liquid injection hole was provided 90 degrees perpendicular to the surface of the lid, and the liquid injection hole was sealed using a sealing plug. As shown in FIG. 4, the step portion 4 has a diameter of 2.0 mm and a depth of 0.5 mm, and a liquid injection hole 7 having a through hole having a diameter of 1.2 mm and a depth of 0.5 mm in the center is provided. A lid 2 made of aluminum alloy (A3003) was fitted into a battery can and welded. An electrolytic solution is injected from the injection hole 7, a sealing plug 1 having a diameter of 2.0 mm and a thickness of 0.5 mm of the flange portion 3 is press-fitted into the injection hole 7, and sealed by laser welding to be a lithium ion battery. Was made.

  About 500 produced lithium ion batteries, when the sealing state after welding was confirmed by laser processing, three welding defects by a pinhole generate | occur | produced. Further, the battery can was disassembled and the battery element was confirmed, but there was no damage by the laser beam.

  From Examples 1 to 3 and Comparative Example 2, it is possible to seal by welding by laser processing without using a sealing plug in the electrolyte injection hole, and quality is higher than using a sealing plug for poor welding. It was found that an excellent sealed battery could be obtained. Moreover, the manufacturing method was also found.

  From Example 1 and Comparative Example 1, it is possible to seal the laser element without damaging the battery element by entering the inside of the battery can by providing a liquid injection hole that is inclined and penetrates the surface of the lid. I found it possible.

  Considering the results of the examples in total, by providing the liquid injection hole with an inclination with respect to the surface of the lid, a sealing plug is not used for the liquid injection hole, and the laser light can be It was found that a sealed battery capable of being welded and sealed by laser processing without entering the inside and damaging the battery element can be obtained, and a manufacturing method thereof can also be provided.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to these embodiments, and the present invention is not limited to the scope of the present invention. Included in the invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

FIG. 1A is a perspective view of a sealed battery, FIG. 1B is a plan view of the sealed battery, and FIG. 1C is FIG. 1B. FIG. 1D is a cross-sectional view illustrating the sealed state of FIG. 1C. It is a figure explaining another injection hole of the sealed battery of this invention, FIG.2 (a) is a top view of a sealed battery, FIG.2 (b) is AA sectional drawing of Fig.2 (a), FIG.2 (c) is sectional drawing explaining the sealing state of FIG.2 (b). It is a figure explaining another injection hole of the sealed type battery of this invention, Fig.3 (a) is a top view of a sealed type battery, FIG.3 (b) is AA sectional drawing of Fig.3 (a). FIG. 3C is a cross-sectional view illustrating the sealed state of FIG. 4A and 4B are diagrams illustrating a conventional sealed battery, in which FIG. 4A is a plan view of the sealed battery, FIG. 4B is a cross-sectional view of a sealing plug, and FIG. 4C is a cross-sectional view of FIG. AA sectional drawing and FIG.4 (d) is sectional drawing explaining the sealing state which inserted the sealing stopper in FIG.4 (c). FIGS. 5A and 5B are diagrams illustrating a sealed battery in which a liquid injection hole is provided vertically and does not use a sealing plug, FIG. 5A is a plan view of the sealed battery, and FIG. 5B is A in FIG. -A sectional drawing, FIG.5 (c) is sectional drawing explaining the sealing state of FIG.5 (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing plug 2 Cover body 3 Flange part 4 Step part 5 Battery can 6 Electrode terminal 7 Injection hole 8 Laser welding part

Claims (2)

  In a sealed battery in which a lid is placed and sealed in the opening of the battery can, the center of the lid that seals the opening of the battery can is inclined with respect to the surface of the lid A sealed battery characterized in that an electrolyte injection hole is sealed by laser processing.   In a manufacturing method of a sealed battery in which a lid is placed and sealed in an opening of a battery can, after the battery element is stored inside the battery can, the lid for sealing the opening of the battery can A sealed type characterized by injecting an electrolyte from an electrolyte injection hole provided at a central portion with an inclination with respect to the surface of the lid, and then welding and sealing the injection hole by laser processing Battery manufacturing method.

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