Method for manufacturing sealed battery and sealed battery manufactured thereby
A method for manufacturing a sealed battery according to one embodiment of this invention includes a first step of using an outer can 15 having an opening, and a sealing plate 16 having a flange provided with a groove 22 around or on a part of a fitting face of the sealing plate 16 with the outer can 15 , and inserting the sealing plate 16 into the opening of the outer can 15 so that a top face of the outer can 15 is approximately flush with a top face of the flange of the sealing plate 16 , and a second step of welding together the outer can 15 and the sealing plate 16 by radiating a high energy ray to the fitting portion therebetween. The invention thus makes it possible to provide a method for manufacturing a sealed battery in which a weld formed by welding a sealing plate fitted into an opening of an outer can of a battery with a laser or other high energy rays has a large breaking strength, and a sealed battery manufactured thereby.
1. A method for manufacturing a sealed battery, comprising:
(1) using an outer can having a portion defining an opening, and a sealing plate having a portion defining a groove formed around or on a part of a fitting face of said sealing plate with said outer can, and inserting said sealing plate into said opening of said outer can so that a top face of said outer can is flush with a top face of a flange of said sealing plate being on an upper side of the groove; and
(2) welding together said outer can and said sealing plate by applying a high energy ray to a fitting portion between said opening of said outer can and said top face of said flange of said sealing plate, wherein molten metal generated from said welding is deposited in said groove;
wherein said groove is formed on a lower side of said top face of said flange of said sealing plate and said upper side of said groove is covered by said top face of said flange, and
wherein the minimum distance from the top face of said flange of said sealing plate to the top of said groove being on a lower side of said flange is at least 0.1 mm.
2. The method for manufacturing a sealed battery according to claim 1 , wherein said sealing plate comprises an electrode connected thereto such that said electrode is inserted into said outer can together with said sealing plate during said first step.
3. The method for manufacturing a sealed battery according to claim 1 , wherein said groove is provided to have a distance H from said top face of said flange of said sealing plate of 0.10 to 0.20 mm, a width W of 0.10 to 0.20 mm, a depth D of 0.10 to 0.15 mm, and a rise angle θ toward said top face of 0° to 60°.
4. The method for manufacturing a sealed battery according to claim 1 , wherein said high energy ray includes one of a laser beam and an electron beam.
5. A sealed battery formed by following the method steps of claim 1 , comprising:
an outer can including a portion defining an opening;
a sealing plate fitted into said opening of said outer can; and
a melted and solidified portion formed by radiating a high energy ray to or around a fitting face of said sealing plate with said outer can so that said sealing plate and said outer can are welded together;
a longitudinal section of said melted and solidified portion where an outer surface of said outer can is placed closest to said sealing plate having a mountain-like shape rising from a deepmost part of said melted and solidified portion outwardly of said outer can, and
said deepmost part of said melted and solidified portion existing in a fitting position between said outer can and said sealing plate or on said sealing plate side rather than on said outer can side.
6. The sealed battery according to claim 5 , wherein an inflection point exists on a boundary in said longitudinal section between said melted and solidified portion on said sealing plate side and a non-melted portion.
7. A method for manufacturing a sealed battery, comprising:
using an outer can having a portion defining an opening, and a sealing plate having a fitting face adapted to fit with said outer can and a portion defining a groove formed around or on a part of said fitting face of said sealing plate with said outer can, and inserting said sealing plate into said opening of said outer can so that a top face of said outer can is approximately flush with a top face of a flange of said sealing plate being on an upper side of the groove; and then
welding together said outer can and said sealing plate by applying a high energy ray to a fitting portion between said opening of said outer can and said top face of said flange of said sealing plate, wherein molten metal generated from said welding is deposited in said groove;
wherein said groove is formed on a lower side of said top face of said flange of said sealing plate and said upper side of said groove is covered by said top face of said flange, and
wherein the minimum distance from the top face of said flange of said sealing plate to the top of said groove being on a lower side of said flange is at least 0.1 mm.
8. The method for manufacturing a sealed battery according to claim 7 , wherein said sealing plate comprises an electrode connected thereto such that said electrode is inserted into said outer can together with said sealing plate during said first step.
9. The method for manufacturing a sealed battery according to claim 7 , wherein said groove is provided to have a distance H from said top face of said flange of said sealing plate of 0.10 to 0.20 mm, a width W of 0.10 to 0.20 mm, a depth D of 0.10 to 0.15 mm, and a rise angle θ toward said top face of 0° to 60°.
10. The method for manufacturing a sealed battery according to claim 7 , wherein said high energy ray includes one of a laser beam and an electron beam.