JP3878732B2 - Alloy type temperature fuse manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an alloy-type temperature fuse .
[0002]
[Prior art]
In the alloy type temperature fuse, a low melting point soluble alloy piece is used for the fuse element, and the power supply to the device is cut off by the melting of the low melting point soluble alloy piece due to abnormal heat generation of the device to protect the device. ing.
In recent years, there has been a demand for thinner temperature fuses as devices become smaller. For example, in a lithium ion secondary battery, it has been proposed to hold a flat temperature fuse between a positive electrode lid end portion and a safety valve plate end portion that are caulked and fixed at the upper end portion of the negative electrode can via a gasket. However, the thickness required for this flat temperature fuse is an ultrathin thickness of 1 mm or less due to the size of the battery.
[0003]
FIG. 6 shows an example of the above flat temperature fuse. Plate electrodes 4 'and 4' are provided above and below an insulating spacer 3 'having a central hole 31', and these plate electrodes 4 'are provided. , 4 ', a low melting point soluble alloy piece 20' as a fuse element is bridged.
In order to make the flat temperature fuse ultra thin, it is effective to form the low melting point soluble alloy piece in a foil shape. For example, a circular cross section having a diameter of 700 μm has the same cross sectional area as a cross section of a foil having a thickness of 100 μm and a width of 4000 μm. By making such a foil shape, the thickness of the low melting point soluble alloy piece can be reduced to 1/7. It is effective to form a low melting point soluble alloy piece in the form of a foil.
[0004]
[Problems to be solved by the invention]
In the alloy type temperature fuse incorporated in the above battery, even under normal conditions, it receives thermal stress due to, for example, daily temperature change or seasonal temperature change. In order to ensure stable electrical contact, it is necessary to weld the contact point.
However, if we attempt to weld the low-melting-point soluble alloy foil and the plate electrode with the contact of the heating block, the low-melting-point soluble alloy foil is melted quickly and before the plate electrode reaches a temperature at which it can be welded. The low melting point soluble alloy foil is melted and welding is difficult. In contrast, instantaneous welding, such as spot resistance welding or laser welding, is unlikely to cause the fusing, but the welding spot of the low melting point soluble alloy foil is scattered by strong concentrated heat energy, which is satisfactory. We can't expect welding.
[0005]
It is an object of the present invention to produce a foil-like connecting conductor that can be safely welded to an ultra-thin alloy type temperature fuse plate electrode.
[0006]
[Means for Solving the Problems]
The method for producing an alloy-type temperature fuse according to claim 1 includes a foil conductor, a melting point lower than that of the foil conductor, a thickness larger than the thickness of the foil conductor, and a width of the foil conductor. A shaft-shaped conductor having a width smaller than the width is connected by welding, and then the connecting portion and the shaft-shaped conductor are compressed to form a foil.
The method for producing an alloy-type temperature fuse according to claim 2 is characterized in that the foil-shaped conductor has a lower melting point and a thickness larger than the thickness of the foil-shaped conductor, and the width is the same as the foil-shaped conductor. A shaft-shaped conductor smaller than the width of the conductor is connected by welding, and then a foil-shaped connecting conductor formed by compressing both connecting portions and the shaft-shaped conductor to form a foil is disposed between the plate electrodes. It is characterized by welding between the plate-like conductor and each plate electrode.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 (a) to 1 (c) show an example of a method for producing a foil-like connection conductor according to the present invention. The foil-like connection conductor has a thickness of 50 to 200 μm and is connected to a copper foil / low melting point metal foil. Is the body.
In order to manufacture this copper foil / low melting point metal foil assembly, first, as shown in FIG. 1A, the copper foil 1 has a lower melting point and a cross-sectional area of the copper foil 1 than the copper foil 1. The axial conductor 2 having a substantially circular cross section substantially equal to the cross sectional area (about 0.7 to 1.5 times) is welded. For heating at the time of welding, heating by contact of a heating block, hot air heating, direct current heating (upset welding) or the like can be used.
Next, as shown in FIG. 1B, the welded portion and the shaft-shaped conductor are pressed to form a foil having the same thickness as the copper foil. For forming the foil, a method of passing through a rolling roll in which the gap is set to a copper foil thickness, a method of compressing with a press, or the like can be used.
After the completion of the foil formation, as shown in FIG. 1 (c), both ends of the width are trimmed so as to be aligned with the width of the copper foil, thereby completing the production of the copper foil / low melting point metal foil connection body. .
In the above, it is possible to use a metal foil having a higher melting point than the low melting point metal foil, for example, an aluminum foil, in addition to the copper foil.
Also, the foil conductor has a rectangular cross section (for example, a square or a rectangle) or an oval low melting point axial conductor whose thickness is larger than the thickness of the foil conductor and whose width is smaller than the width of the foil conductor. Can also be used.
[0008]
In the method for manufacturing a foil-like connecting conductor according to the present invention, the low-melting point metal conductor is welded to the high-melting point foil-like conductor in the shape of the shaft before forming the foil, and the strength under the same cross-sectional area is the foil. The shaft shape is higher than the shape, and even if the low melting point metal is softened at the welding temperature, it is less likely to break than the foil shape under the shaft shape. The melting point metal conductor can be easily welded with good prevention. Further, the foil formation of the welded shaft body low-melting point metal conductor is a spreading process and is not subjected to a tensile force, so that it can be easily formed into a foil shape without breaking the shaft body low-melting point metal conductor. Therefore, according to the present invention, a foil-like connection conductor such as a copper foil / low melting point metal foil connection conductor can be easily manufactured.
[0009]
FIG. 2 shows an example of a thin temperature fuse in which the copper foil / low melting point metal foil connecting conductor A manufactured according to the present invention is a fuse element.
In FIG. 2, 3 is an insulating spacer having a central hole 31, and uses a heat-resistant plastic film (for example, polyethylene terephthalate, polyamide, polyimide, polyphenylene sulfide, etc.) or a ceramic plate. it can. Reference numerals 4 and 4 denote plate electrodes fixed to the upper and lower surfaces of the insulating spacer 3 by an adhesive 41, and a metal foil such as a copper foil can be used. a shows the foil-shaped connection conductor manufactured by this invention, is the structure which has the copper foil piece 10 in the both ends of the low melting metal foil 20, accommodates the low melting metal foil 20 in the center hole 31, and each copper foil piece 10 Is sandwiched between the upper and lower end surfaces of the insulating spacer 3 and each plate electrode 4, and the copper foil pieces 10 and each plate electrode 4 are welded by spot resistance welding or laser welding. It is. Reference numeral 5 denotes a flux filled in the central hole 31.
[0010]
In order to manufacture the alloy type temperature fuse shown in FIG. 2, the low melting point metal foil 20 having the copper foil pieces 10 at both ends manufactured in the invention of claim 1 is formed in the central hole 31 of the insulating spacer 3. After the hole 31 is filled with the flux 5, the plate electrode 4 is fixed to the upper and lower surfaces of the insulating spacer 3 with an adhesive 41, and each copper foil piece 10 is connected to each plate electrode 4 and the insulating spacer. -Hold between the upper and lower surfaces of the heater 3 and then weld each copper foil piece 10 and each plate electrode 4 by spot resistance welding, laser welding, or the like. Finishing the production.
Since the welding of the copper foil piece 10 and the plate electrode 4 is performed instantaneously and in a spot manner, the heat conduction to the low melting point metal foil 20 at the time of welding can be sufficiently eliminated, and the low melting point metal foil 20. Can be kept stable.
Therefore, in the alloy type temperature fuse manufactured in the invention of claim 2, in the alloy type temperature fuse as shown in FIG. 6, the low melting point metal foil 20 'is concentrated in a spot manner in the heat energy. Thus, it is possible to eliminate the scattering of the low melting point metal that occurs when welding directly to the plate electrode 4 ', and to provide stable electrical conduction through safe welding between the low melting point metal foil and the plate electrode. Can be guaranteed.
[0011]
FIG. 3 shows another example of an alloy type temperature fuse manufactured according to the second aspect of the present invention.
In order to produce this alloy type temperature fuse according to the invention of claim 2, the low melting point metal foil 20 having the copper foil pieces 10 and 10 produced at the both ends produced by the invention of claim 1 is insulated. 3 along the inner surface of the central hole 31 from the upper and lower surfaces, and the central hole 31 is filled with flux 5, and the plate electrode 4 is fixed to the upper and lower surfaces of the insulating spacer 3 with an adhesive 41. The electrode 4 and each copper foil piece 10 are welded by spot resistance welding, laser welding, or the like, thereby completing the production of the alloy type temperature fuse.
[0012]
In the alloy type temperature fuse shown in FIGS. 2 and 3, the thickness of the plate electrode 4 is 50 μm to 200 μm, the thickness of the low melting point metal foil 20 and the copper foil piece 10 is 50 μm to 200 μm, and the insulating space. The thickness of the substrate 3 is approximately 100 to 900 μm, the thickness of the adhesive layer 41 is 50 to 200 μm, and the total thickness is approximately 300 to 1000 μm. FIG. 4 (A) and FIG. As shown in (R) cross-sectional view in (a)], it is used by being incorporated in a lithium ion secondary battery. In FIG. 4, 61 and 62 are a positive electrode lid and a safety valve plate whose outer periphery is caulked and fixed at the upper end 631 of the negative electrode can 63 via a gasket 64, and a is an annular ultra-thin temperature fuse sandwiched between them. Respectively. Reference numeral 31 denotes a central hole of the insulating spacer.
[0013]
As shown in FIG. 5, the annular part is used as an ultra-thin temperature fuse a and the other part b is used as an auxiliary insulating spacer having the same thickness as the ultra-thin temperature fuse a. You can also
[0014]
【The invention's effect】
According to the present invention, it is possible to easily produce a connection conductor foil in which a high melting point metal foil having the same thickness is welded to both ends of an ultrathin low melting point metal foil having a thickness of 50 to 200 μm. By using it as a fuse element for a temperature fuse, an ultra-thin temperature fuse having a thickness of 1000 μm or less can be manufactured.
[Brief description of the drawings]
FIG. 1 is a drawing showing a method for producing a foil-like connecting conductor according to the present invention.
FIG. 2 is a drawing showing an example of a temperature fuse using a foil-like connection conductor manufactured according to the present invention.
FIG. 3 is a view showing another example of a temperature fuse using a foil-like connection conductor manufactured according to the present invention.
4 is a view showing an example of a state in which the temperature fuse shown in FIG. 2 or FIG. 3 is installed in the battery.
5 is a drawing showing another example of a state in which the temperature fuse shown in FIG. 2 or FIG. 3 is installed in the battery.
FIG. 6 is a view showing a conventional flat temperature fuse.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Foil-shaped conductor 2 Shaft-shaped conductor A Copper foil and low melting-point metal foil connection conductor 10 Copper foil 20 Low-melting-point metal foil 3 Insulation spacer 31 Center hole 4 of an insulation spacer 4 Plate electrode

Claims (2)

The foil-shaped conductor and a shaft-shaped conductor having a lower melting point than the foil-shaped conductor and having a thickness larger than the thickness of the foil-shaped conductor and a width smaller than the width of the foil-shaped conductor are connected by welding. After that, a method for producing an alloy-type temperature fuse, wherein the connecting portion and the shaft-like conductor are compressed into a foil shape. An axial conductor having a melting point lower than that of the foil conductor and larger than the thickness of the foil conductor and having a width smaller than that of the foil conductor is connected by welding between the foil conductors. After that, the foil-like connecting conductor formed by compressing both connecting portions and the shaft-like conductor to form a foil is arranged between the plate electrodes, and welding between each foil-like conductor and each plate electrode is performed. A method for producing an alloy-type temperature fuse.

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