JP4566447B2 - Thin fuse manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a thin fuse, particularly a thin substrate-type thermal fuse.
[0002]
[Prior art]
A thermal fuse uses a low melting point soluble alloy piece as a fuse element. For example, in a substrate type thermal fuse, a pair of fuse mounting electrodes is provided on a substrate, and a low melting point soluble alloy piece is provided between these electrodes. Are connected, a flux is applied to the low melting point soluble alloy piece, and the flux coated low melting point soluble alloy piece is sealed with a sealing resin or the like.
In order to protect electronic and electrical equipment with this thermal fuse, the thermal fuse is attached to the equipment, the low melting point soluble alloy piece of the thermal fuse is melted by the heat generated by the equipment abnormality, The spheroidization of the molten alloy due to surface tension is promoted and the energization is cut off by the spheroidization of a predetermined insulation distance, thereby preventing the fatal damage of the equipment and the occurrence of fire.
[0003]
Recently, secondary batteries with a large volumetric energy density, particularly lithium ion secondary batteries, are frequently used as power sources for portable electronic devices such as notebook computers, mobile phones, and digital cameras.
In this secondary battery, when an abnormality such as a short circuit occurs, abnormal heat generation occurs due to intense Joule heat generation due to the large built-in energy, and in an extreme case, explosion occurs due to rapid internal pressure generation.
Thus, by detecting this abnormal heat generation, the battery is opened between ± electrodes to cut off the overcurrent, thereby preventing the battery from exploding.
The above-mentioned portable device is particularly required to be downsized due to its model. Thus, the thermal fuse is also required to be thinned in response to the miniaturization of the portable device, and the thinning is achieved by thinning the substrate, the sealing layer, and the low melting point soluble alloy piece. .
In this case, it is necessary to reduce the thickness of the low melting point soluble alloy piece under the same electric resistance value while maintaining the cross-sectional area as it is in order to prevent self-surreal heat generation of the low melting point soluble alloy piece. Yes, a low melting point soluble alloy wire with a round cross section is flattened.
[0004]
[Problems to be solved by the invention]
When the round wire is flattened under the same cross section, the surface area is increased. This increase in the surface area itself contributes to the quick operation of the fuse by increasing the contact area with the coating flux. However, since the surface area is larger than the cross-sectional area, if the amount of oxide film per unit surface area is the same, the amount of oxide becomes large and the operation speed of the fuse is lowered.
[0005]
That is, the surface area of the round wire and the surface area S of the flattened wire are expressed as follows.
[Expression 1]
S / s≈ (2α / π) + (1 / 2α) (1)
For example, when the flatness α is 0.2, S / s≈2.5, and the amount of the oxide is about 2.5 times.
[0006]
Therefore, the oxide film on the surface of the low melting point soluble alloy piece of the thermal fuse is hard and has a higher melting point than the low melting point soluble alloy, and even if the low melting point soluble alloy piece is melted, this oxide film sheath is retained. As long as the spheroidization is not started as long as the oxide sheath is solubilized with the flux, the spheroidization starts only after the oxide film sheath is solubilized with the flux. As long as it is increased, a delay in operating the thermal fuse is inevitable.
[0007]
The object of the present invention is to manufacture a low-melting-point fusible alloy piece surface in spite of using a low-melting-point fusible alloy piece flattened with a low-melting-point fusible alloy wire having a round cross-section for manufacturing a thermal fuse. It is to make it possible to manufacture a thin thermal fuse with excellent operability by suppressing oxidation.
[0008]
[Means for Solving the Problems]
The thin fuse manufacturing method according to the present invention continuously feeds a continuous low melting point soluble alloy wire while flattening, supplies the flattening delivery low melting point soluble alloy wire to a predetermined length on a substrate, The length portion is cut and fixed to the substrate, and the flattened low melting point soluble alloy piece fixed substrate is sent to the flux application stage to apply flux to the flattened low melting point soluble alloy piece. A method of manufacturing a fuse for sealing a melting point soluble alloy piece with a sealing material, and flattening a low melting point soluble alloy piece fixing substrate while supplying a flattened low melting point soluble alloy wire to a predetermined length on the substrate Is sent to the flux application stage.
[0009]
Another method of manufacturing a thin fuse according to the present invention is to continuously feed out a continuous low melting point soluble alloy wire while flattening, supplying the flattened feeding low melting point alloy wire to a predetermined length on a substrate, The predetermined length portion is fixed to the substrate and cut, and then the flattened low melting point soluble alloy piece fixed substrate is sent to the flux application stage to apply the flux to the cut flattened low melting point soluble alloy piece, and the flux is applied. A method for manufacturing a fuse in which a flattened low melting point soluble alloy piece is sealed with a sealing material, and the flattened low melting point soluble alloy wire is supplied to the substrate for a predetermined length on the flattened low melting point soluble alloy wire. The single-fixed substrate is sent to a flux application stage.
[0010]
The surface roughness of the flattened low melting point soluble alloy piece is preferably 0.05 to 10 μm. Further, the flattening dimensions are usually 0.02 to 0.3 mm in thickness and 0.1 to 3 mm in width.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a thin thermal fuse manufactured according to the present invention. Electrodes 12 and 12 are provided on one side of an insulating substrate, 11 a rigid substrate such as a ceramic substrate, or a flexible substrate such as a plastic film. The flattened low melting point soluble alloy piece a is connected by welding or the like, the flux b is applied to the flattened low melting point soluble alloy piece a, the strip-like lead conductors 13 and 13 are connected to the respective electrodes, and the one side of the substrate is made of resin. It is sealed with a sealing material 14 such as a film, an epoxy resin, or a case.
[0012]
2A is a side view showing a production line of a thermal fuse used in the present invention, and FIG. 2B is a plan view.
In FIG. 2, A is a low melting point soluble alloy wire having a round cross section, and 2 is its supply bobbin. 3 is a roll rolling device, which comprises a rolling twin roll 31, a pre-rolling tension adjusting roll 32, a post-rolling tension adjusting roll 33, a width measuring sensor 34, and a tension control 35. When the rolling width reaches the lower limit, Detected by the width measurement sensor 34, the tension adjustment roll 32 before rolling is accelerated by the tension control 35 (or the tension adjustment roll 33 after rolling is decelerated), and when the rolling width reaches the upper limit value, this is measured. 34, the tension adjusting roll 32 before rolling is decelerated by the tension control 35 (or the tension adjusting roll 33 after rolling is increased) to keep the rolling width within a certain range.
Reference numeral 11 denotes a thermal fuse substrate, which includes fuse mounting electrodes 12 and 12. Reference numeral 4 denotes a fast-feed conveyor line. Reference numeral 5 denotes a flattened low-melting-point soluble alloy piece mounting station provided in the fast-feed conveyor line 4, which is disposed on the downstream side of the rolling line. 6 is a welding station disposed on the downstream side of the flattening low melting point soluble alloy piece placement station 5 of the fast-feed conveyor line 4, and 7 is disposed on the downstream side of the fast-feed conveyor line of the welding station 6 of the fast-feed conveyor line 4. This is a flux application station.
[0013]
In order to manufacture a thermal fuse according to the present invention using the above production line, the rolling line of the low melting point soluble alloy wire A is continuously driven, and the flattened low melting point soluble alloy wire A ′ is rolled and the tension adjusting roll 33 is rolled. It is fed out at a predetermined linear speed.
The flattened low melting point soluble alloy piece mounting station 5 is made to wait for the thermal fuse substrate 11, and when the tip of the flattened low melting point soluble alloy wire A ′ reaches the outer electrode 11a of the substrate, Is detected by a sensor 51 (either a contact sensor or an optical sensor), the cutter 52 is operated, the flattened low melting point soluble alloy wire A ′ is cut, and the flattened low melting point soluble alloy piece of the cut piece is obtained. a) is placed on the substrate 11;
[0014]
After the flattened low melting point soluble alloy piece a is placed on the substrate 11 in this way, the next substrate is transported to the flattened low melting point soluble alloy piece placing station 5 by rapid feed of the fast feed conveyor line 4. The flattened low melting point soluble alloy piece mounting substrate is conveyed to the welding station 6, the rapid feed conveyor line 4 is stopped, and the electrodes 12, 12 of the substrate 11 and the flattened low melting point soluble alloy piece a are connected at the welding station 6. Welding, and supplying the tip of the flattened low melting point soluble alloy wire fed from the rolling line on the substrate that is waiting in the flattened low melting point soluble alloy piece mounting station as described above, After cutting with a cutter and placing the flattened low melting point soluble alloy piece on the substrate, the fast-feed conveyor line is fast-forwarded again. In this fast-forwarding conveyor line again, the welded workpiece of the welding station 6 is transferred to the flux application station 7 and the flattened low-melting-point soluble alloy piece placement station of the flattened low-melting-point soluble alloy piece placement station. The finished workpiece is transferred to the welding station 6, immediately after this transfer, the flux is applied at the flux application station 7, and the flattened low melting point soluble alloy piece is welded to the substrate electrode at the welding station. Repeat.
[0015]
In the above, the cycle time of the unwound come off the flattened low melting fusible gold material When t _2, fast-forward conveyor line is stopped as a stop time t ₂ - repeating the fast feed. Then, the feeding speed of the rolling after tensioning roll rolled flattened low melting fusible gold material v, the cut length of the flattened low melting fusible gold material When l, cycle time t ₂ of cleavage ,
[Expression 2]
t ₂ = l / v (2)
During this stop time, welding at the welding station and flux application at the flux application station are performed.
When the distance from the rolled twin roll to the outer electrode of the substrate in the flattened low melting point soluble alloy piece mounting station is W, the flattened low melting point soluble alloy wire is flattened and discharged to the outside air. The exposure time t ₁ is:
(3)
t ₁ = W / v
As mentioned above, the stop time at the welding station is
t ₂ = l / v (4)
If the time required for flux application at the flux application station is t3, the time t from the flattening of the low melting point soluble alloy wire to the end of the flux application is approximately
t = W / v + l / v + t ₃ (5)
(The speed of the fast-feed conveyor line is high, and the feed time by the fast-feed conveyor line is negligible).
[0016]
In the above, the surface area of the wire is increased by flattening the wire having a round cross section by rolling twin rolls, and the oxide film on the surface of the round wire before flattening is cracked and dispersed on the surface of the flat wire after flattening, thereby The substrate portion is oxidized with time. According to the present invention, the time from when the substrate appears until it is applied with the flux, that is, the time t shown in Equation 4 can be extremely shortened. Oxidation of the substrate can be reduced and the formation of a new oxide film can be well suppressed.
[0017]
3A is a side view showing another example of the production line for the thermal fuse used in the present invention, and FIG. 3B is a plan view.
In FIG. 3, A is a low melting point soluble alloy wire having a round cross section, and 2 is its supply bobbin. Reference numeral 3 denotes a roll rolling apparatus, which includes the rolling twin roll 31, the pre-rolling tension adjusting roll 32, the post-rolling tension adjusting roll 33, the width measuring sensor 34, and the tension control 35 as described above.
Reference numeral 11 denotes a thermal fuse substrate having the fuse mounting electrodes 12 and 12 as described above. 4 is a fast-feed conveyor line disposed on the downstream side of the rolling line. Reference numeral 8 denotes a flattened low melting point soluble alloy piece mounting station provided in the fast-feed conveyor line 4, where the flattened low melting point soluble alloy wire tip a ′ is mounted on the substrate 11, welded, and cut. 7 is a flux application station disposed on the downstream side of the fast-feed conveyor line of the flattened low melting point soluble alloy piece mounting station 8 of the fast-feed conveyor line 4.
[0018]
In order to manufacture a thermal fuse according to the present invention using the above production line, the rolling line of the low melting point soluble alloy wire A is continuously driven, and the flattened low melting point soluble alloy wire A ′ is rolled and the tension adjusting roll 33 is rolled. It is fed out at a predetermined linear speed.
In the flattened low melting point soluble alloy piece mounting station 8, the thermal fuse substrate 11 is kept waiting, and when the tip e of the flattened low melting point soluble alloy wire A ′ reaches the outer electrode 12 a of the substrate 11, This is detected by a sensor 81 (which can be either a contact sensor or an optical sensor) and the laser welding machines 82 and 82 are operated to weld the flattened low melting point soluble alloy wire a ′ and the electrodes 12 and 12 of the substrate 11. Then, the flattened low melting point soluble alloy wire portion outside the inner electrode 12b is cut by the laser cutter 83, and the flattened low melting point soluble alloy piece is mounted on the substrate 11.
Next, the fast-feed conveyor line 4 is fast-forwarded to convey the flattened low melting point soluble alloy piece mounting substrate to the flux application station 7 and carry the next substrate into the flattening low melting point soluble alloy piece mounting station 8.
Welding of the flattened low melting point soluble alloy wire to the substrate electrode waiting for the tip of the flattened low melting point soluble alloy wire to reach the outer electrode of the substrate carried into the flattened low melting point soluble alloy piece mounting station And the laser cutting of the flattened low melting point soluble alloy wire portion outside the inner electrode of the substrate is performed, and the flux b is applied to the flattened low melting point soluble alloy piece a mounting substrate 11 conveyed to the flux application station 7. . Thereafter, the above is repeated.
[0019]
During laser welding and laser cutting at the flattened low melting point soluble alloy piece mounting station 8, the flattened low melting point soluble alloy wire mounting end 8 'in the flattened low melting point soluble alloy piece mounting station 8 is stationary. Therefore, a dancer roll is provided between the tension adjusting roll 33 after rolling and the flattened low melting point soluble alloy piece mounting station 8, and laser welding and laser cutting at the flattened low melting point soluble alloy piece mounting station are performed. The amount of the flattened low melting point soluble alloy wire fed from the tension adjusting roll after rolling can be absorbed by the dancer roll. In addition, the rolling line can be stopped instead of absorption by the dancer roll.
[0020]
In the other embodiment, the distance from the rolling twin roll 31 to the outer electrode 12a of the substrate 11 in the flattened low melting point soluble alloy piece mounting station 8 is W, and the dancer roll of the drawn flattened low melting point soluble alloy wire If the absorption amount by w is w, the flattened low melting point soluble alloy wire is flattened and reaches the outer electrode 12a of the substrate of the flattened low melting point soluble alloy piece mounting station 8 while welding and cutting are performed. The time t ₁ ′ exposed to the outside air is:
t ₁ '= (W + w) / v (6)
If the time required for flux application at the flux application station 7 is t3, the time t from flattening of the low melting point soluble alloy wire to the end of flux application is approximately
t = (W + w) / v + t ₃ (7)
(The speed of the fast-feed conveyor line is high, and the feed time by the fast-feed conveyor line is negligible).
[0021]
In the above, the surface area of the wire is increased by flattening the wire having a round cross section by rolling twin rolls, and the oxide film on the surface of the round wire before flattening is cracked and dispersed on the surface of the flat wire after flattening, thereby This substrate portion is oxidized over time, but according to the present invention, the time from when the substrate appears until it is applied with the flux, that is, the time t shown in Equation 7, can be made extremely short. Oxidation of the substrate can be reduced and the formation of a new oxide film can be well suppressed.
[0022]
In the above embodiment, the rolling line of the low melting point soluble alloy wire and the flattened low melting point soluble alloy wire tip mounted on the thermal fuse substrate-cutting-welding-conveying line for flux application or low melting point soluble Aligning the rolling line of alloy wire with the flattened low melting point soluble alloy piece on the thermal fuse substrate (mounting the flattened low melting point soluble alloy wire tip-welding-cutting)-synchronizing the flux coating conveyor line However, if the flattened low melting point soluble alloy wire fixed substrate is sent to the flux application stage at a time interval for cutting the flattened low melting point soluble alloy wire into a predetermined length, the flattening of the low melting point soluble alloy wire is performed. The time from application to flux application can be shortened to the same extent as in the previous embodiment, and the continuous low melting point soluble alloy wire is fed out while flattening, and the flattened drawing out low melting point soluble alloy wire is made to a predetermined length. La to cut And down, the cut flattened low melting fusible alloy piece was fixed to a substrate, the lines of flux is applied to the cut flattened low melting fusible alloy piece can be a independently of one another.
[0023]
According to the method for manufacturing a thermal fuse according to the present invention, it is possible to provide a thermal fuse having excellent quick operation by preventing new oxidation of a flattened low melting point soluble alloy piece. The time from the point of time to the application of the flux can be significantly shortened to minimize new oxidation.
In this case, if the oxide amount per unit surface area is w, the surface area of the flattened low melting point soluble alloy piece is S, and the cross sectional area of the flattened low melting point soluble alloy piece is B, the oxide amount per unit volume x is [Equation 8]
x = wS / B (8)
The surface roughness of the flattened low-melting-point soluble alloy piece is 10 μm or less, in particular, as described in claim 4, in addition to the reduction of w by significantly shortening the time from the flattening time to the flux application. If so, it is possible to substantially reduce S, and it is expected that the fuse operability can be further accelerated.
From an economical viewpoint, it is desirable that the surface roughness of the flattened low melting point soluble alloy piece is 0.05 μm or more.
[0024]
The present invention is more effective as the flatness α of the above formula (1) is larger, and therefore, as the flattening width / thickness ratio is larger. However, the lower limit of the thickness is limited in terms of mechanical strength, and the thickness Since the upper limit and the upper limit of the width are restricted in terms of thinning and downsizing of the thermal fuse, the flattening dimensions are preferably 0.02 to 0.3 mm in thickness and 0.1 to 3 mm in width.
[0025]
In manufacturing a thin fuse according to the present invention, connection and sealing of lead conductors can be performed as usual.
[0026]
In addition, as shown in FIG. 4, the thin fuse has a pair of flat lead conductors 13 and 13 fixed to both ends of one surface of the resin film 11 by fusion or the like, and a flattened low melting point soluble alloy between the lead conductors 13 and 13. The piece a can be welded, the flux b is applied to the flattened low melting point soluble alloy piece a, and one side of the substrate 11 can be sealed by fusing the sealing material 14 of the resin film. In this case, a resin film in which a pair of flat lead conductors are fixed to both ends of one side by fusion or the like is used as the base material in the present invention.
[0027]
【The invention's effect】
According to the thin fuse manufacturing method according to the present invention, after flattening the low melting point soluble alloy wire having a round cross section, the flattened wire is mounted on the substrate under a predetermined cutting length, and the mounted The time until the flux application of the flattened low melting point soluble alloy piece can be made extremely short compared to the conventional example, so that the oxidation of the alloy base caused by flattening can be sufficiently suppressed, and the flattened low melting point soluble alloy The amount of oxide film on one surface can be reduced well, and a thin thermal fuse having quick fusing operation can be manufactured.
Also, since flattening of the low melting point soluble alloy wire is continuously performed (since intermittent flattening is not performed), the cross-section of the flattened low melting point soluble alloy piece is made uniform and the Heisei form is smoothed. Can guarantee.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a thin fuse manufactured according to the present invention.
FIG. 2 is a drawing showing an embodiment of the present invention.
FIG. 3 is a drawing showing another embodiment of the present invention.
FIG. 4 is a view showing another example of a thin fuse manufactured according to the present invention.
[Explanation of symbols]
A continuous low melting point soluble alloy wire A 'flattened low melting point soluble alloy wire a flattened low melting point soluble alloy piece 11 substrate 12 electrode 3 rolling apparatus b flux

Claims (6)

The continuous low melting point soluble alloy wire is continuously fed out while being flattened, the flattened feeding low melting point soluble alloy wire is supplied to the substrate for a predetermined length, and the predetermined length portion is cut and fixed to the substrate. Then, this flattened low melting point soluble alloy piece fixed substrate is sent to the flux application stage to apply the flux to the flattened low melting point soluble alloy piece, and the flux coated flattened low melting point soluble alloy piece is sealed with a sealing material. A method of manufacturing a fuse for stopping, wherein the flattened low melting point soluble alloy wire is fed to the flux coating stage while the flattened low melting point soluble alloy wire is supplied to the substrate for a predetermined length. Thin fuse manufacturing method. A continuous low melting point soluble alloy wire is continuously fed out while being flattened, the flattened feeding low melting point soluble alloy wire is supplied to the substrate for a predetermined length, and the predetermined length portion is fixed to the substrate and cut. The flattened low melting point soluble alloy piece fixed substrate is sent to the flux application stage to apply the flux to the cut flattened low melting point soluble alloy piece, and the flux coated flattened low melting point soluble alloy piece is sealed with a sealing material. A method of manufacturing a fuse for sealing, characterized in that a flattened low melting point soluble alloy wire fixed plate is sent to a flux application stage while a flattened low melting point soluble alloy wire is supplied to the substrate for a predetermined length. Manufacturing method for thin fuse. The continuous low melting point soluble alloy wire is continuously drawn out while being flattened, the flattened drawn low melting point soluble alloy wire is cut into a predetermined length, and the cut flattened low melting point soluble alloy piece is fixed to the substrate. The flattened low melting point soluble alloy piece fixed substrate is sent to the flux application stage to apply the flux to the cut flattened low melting point soluble alloy piece, and the flux coated flattened low melting point soluble alloy piece is sealed with a sealing material. A method for manufacturing a fuse to be sealed, wherein the flattened low melting point soluble alloy wire is cut to a predetermined length and the flattened low melting point soluble alloy piece fixed substrate is sent to the flux application stage. Thin fuse manufacturing method. The method for producing a thin fuse according to any one of claims 1 to 3, wherein the flattened low melting point soluble alloy piece has a surface roughness of 10 µm or less. The method for manufacturing a thin fuse according to any one of claims 1 to 4, wherein the flattening dimensions are 0.02 to 0.3 mm in thickness and 0.1 to 3 mm in width. The method for producing a thin fuse according to any one of claims 1 to 5, wherein the continuous low melting point soluble alloy wire is flattened by a twin-rolling roll.

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