JP2010140710A - Alloy type thermal fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alloy type thermal fuse which can secure stability of flux action even when it is left in a severe condition for long time. <P>SOLUTION: In the thermal fuse, in which a low-melting alloy element 2 with a flux 3 applied thereto is sealed with a cured resin 5, a mixture of an anaerobic cured resin and an ultraviolet cured resin is employed for the cured resin 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alloy type thermal fuse.

The alloy-type thermal fuse has a configuration in which a low melting point alloy element is welded between lead conductors, a flux is applied to the low melting point alloy element, and the flux coated low melting point alloy element is sealed with a sealing material.
This sealing needs to be performed at a temperature that does not melt the flux applied to the low melting point alloy element, and it is safe to seal with a room temperature curable resin.

Therefore, it is known to perform sealing in an alloy-type thermal fuse with an ultraviolet curable resin (Patent Documents 1 to 3, etc.).
JP 2001-43783 A JP 2001-148220 A JP 2006-228657 A

  However, in sealing with ultraviolet curable resin, it is difficult to sufficiently irradiate ultraviolet rays to the point where it comes into contact with the flux-coated low-melting point alloy element, and the sealing resin part in contact with the flux-coated low-melting point alloy element is uncured or unstable due to insufficient curing The active group of the flux, for example, —COOH, reacts and the function of the flux may be impaired.

  An object of the present invention is to provide an alloy-type thermal fuse that can ensure the stability of the flux action even if left for a long time under harsh conditions.

The alloy-type thermal fuse according to claim 1 is a thermal fuse that seals against a flux-coated low-melting-point alloy element with a cured resin, wherein a mixture of an anaerobic curable resin and an ultraviolet curable resin is used as the cured resin. To do.
In the alloy type thermal fuse according to claim 2, a low melting point alloy element is welded between lead conductors, a flux is applied to the low melting point alloy element, the flux coated low melting point alloy element is sandwiched between upper and lower insulating films, The space between the films is filled with a mixture of an anaerobic curable resin and an ultraviolet curable resin.
The alloy type thermal fuse according to claim 3 is the alloy type thermal fuse according to claim 1 or 2, wherein the volume ratio of the anaerobic curable resin to the ultraviolet curable resin is 5: 1 to 5: 3. And
The alloy-type thermal fuse according to claim 4 is the alloy-type thermal fuse according to claim 2 or 3, wherein a curing accelerator is applied to at least one of the inner surfaces of the upper and lower insulating films and the lead conductor portion in contact with the resin mixture. It is characterized by.
The alloy-type thermal fuse according to claim 5 is the alloy-type thermal fuse according to any one of claims 1 to 4, wherein the surface of the flux-coated low-melting-point alloy element has the same component as the flux and is adjusted to have a higher melting point than the flux. An intermediate layer having the above composition is provided.

(1) In the alloy type thermal fuse of claim 1, since a mixture of an anaerobic curable resin and an ultraviolet curable resin is used as the curable resin sealing material, the surface of the sealing body in contact with the outside air is irradiated with ultraviolet rays. The anaerobic curable resin component in the mixture is cured and the surface thereof becomes airtight. By this airtightness, the intrusion of air into the sealed body is surely blocked, and the anaerobic curable resin component of the mixture inside the sealed body can be rapidly cured to quickly cure the interior.
(2) The alloy-type thermal fuse of claim 2 has a structure in which a sealing material is buried between upper and lower insulating films, and the sealing body volume with respect to the surface area of the outer surface of the sealing body around the insulating film is considerably large. Therefore, in addition to the fact that the anaerobic cured resin component is inherently cured early, further early curing of the inside can be achieved by the early airtightness of the outer surface of the sealing body.
(3) The ultraviolet curable resin component plays a role of making the outer surface of the sealing body airtight and blocking the ventilation into the sealing body to promote the curing of the anaerobic curable resin component. In claim 3, after confirming this technical significance, an appropriate mixing ratio of the anaerobic curable resin and the ultraviolet curable resin is determined.
(4) According to claim 4, by applying a curing accelerator made of fine metal powder to the sealing surface, the sealing strength at the interface is strengthened, and the mechanical strength and curing reliability of the exterior are improved. it can.
(5) According to claim 5, although the temperature fuse is lower than the melting point of the low melting point alloy element, even if the flux is melted by being heated to a temperature higher than the melting point of the flux, the flux and hardening are caused by the barrier action of the intermediate layer. Reaction with the resin can be surely eliminated.

Embodiments of the present invention will be described below with reference to the drawings.
1-1 is a perspective view showing an alloy type thermal fuse according to the present invention, and FIG. 1-2 is a cross-sectional view taken along the line II in FIG. 1-1.
1-1 and FIG. 1-2, 1 and 1 are a pair of strip | belt-shaped lead conductors, A nickel conductor, a copper conductor, etc. can be used. The surface of the nickel conductor can be plated or clad with Sn, Au, Cu, Ag or the like, and the copper conductor can be coated with Ni as a copper migration blocking film in addition to the entire surface or a portion where the low melting point alloy piece is welded. It can be plated or clad, and Sn, Au, Cu, Ag, etc. can also be plated on Ni.
Reference numeral 2 denotes a low melting point alloy element, the upper surface of which is a curved surface with a tangent angle increasing toward both ends, and a portion 20 of the intermediate portion is inserted between the leading ends 11 and 11 of the opposing lead conductors. Is welded to the upper surface of the end of each strip-shaped lead conductor 1,1. As the material of the low melting point alloy element, In-Bi, Sn-In-Bi, and alloys such as Cu, Ag, Sb, Zn are used for improving mechanical strength and adjusting temperature characteristics. What added 0.1-4.0 mass% can be used.
The volume of entry of the low melting point alloy element between the leading ends of the opposing lead conductors is 10 to 20% of the total volume of the low melting point alloy element. The lower surface of the intrusion portion 20 and the lower surfaces of the strip-shaped lead conductors 1 and 1 can be substantially flush with each other.
A flux 3 is applied to the low melting point alloy element, and rosin or rosin added with an activator, for example, carboxylic acid can be used.

In FIGS. 1-1 and 1-2, reference numerals 4 and 4 denote upper and lower insulating films, and engineering plastic films such as PET, PC, and PEN, glass cloth base epoxy resin films, and the like can be used. It is also possible to use a single sheet that is used.
5 is a mixture of an anaerobic curable resin and an ultraviolet curable resin, which fills the space between the upper and lower films, and the upper flux 31, the exposed surface of the low melting point alloy element 2 with respect to the upper flux 31, and the lower flux 32 are the mixture 5. Is in contact with An anaerobic curable resin is a polyvalent acrylic acid ester that can be radically polymerized at room temperature, or a mixture thereof, such as diethylene methacrylate of tetraethylene glycol, and free radicals are generated from the time when the action of oxygen on the mixture is turned off, resulting in polyacrylic acid. Combined with a substance that initiates radical polymerization of acid esters and maintains or accelerates polymerization, generally combined with organic peroxides or hydroperoxides such as cumyl hydroperoxide and dimethylbalatlidene An acrylate oligomer resin can be used. As the ultraviolet curable resin, a methacrylate oligomer resin can be used.
The volume ratio of anaerobic curable resin: UV curable resin is preferably 5: 1 to 5: 3.

  FIG. 2-1 shows a low melting point alloy element with a lead conductor. In the illustrated example, the width of the low melting point alloy element 2 and the width of the strip-shaped lead conductors 1 and 1 are made equal, but the width of the low melting point alloy element can be made narrower than the width of the strip-shaped lead conductor.

In order to obtain the low melting point alloy element with the lead conductor shown in FIG. 2-1, as shown in FIG. 2B, the lead is placed on a work table A that is heat resistant and releasable from the molten alloy, for example, a stainless steel base. Whether the conductor base materials 100 and 100 are arranged at a predetermined gap interval, are melted with the soldering iron B while supplying a low melting point alloy wire between the base materials, and the molten alloy 200 is solidified with a curved surface determined by the surface tension. A method can be used in which a molten alloy is supplied by a traveling nozzle, solidified on a curved surface determined by surface tension, and then cut into a strip shape.
In the low melting point alloy element portion that has entered between the leading ends of the opposing lead conductors, a constriction 22 is processed as shown in FIG. 2-1, in order to easily cause spheroidization of the low melting point alloy element. can do.

In FIG. 2, reference numerals 31 and 32 denote fluxes, which are applied to the upper surface side of the low melting point alloy element as indicated by reference numeral 31, and the lower surface of the entry portion 20 of the low melting point alloy element and the strip-shaped leads that are present on the lower surface. It is applied to the lower surface portion of the conductor as indicated by reference numeral 32.
The upper flux 31 is applied so as to cover 70% or more of the low melting point alloy element portion welded to the upper surface of the end portion of the strip-shaped lead conductor, and covers the entire upper surface of the low melting point alloy element to reach the upper surface of the strip-shaped lead conductor. It can also be made. The coating thickness of the upper surface side flux is preferably 70 to 100% of the average thickness of the low melting point alloy element portion welded to the upper surface of the end portion of the strip-shaped lead conductor.
The coating thickness of the lower flux is the lower insulator thickness (lower film and lower adhesive, to ensure heat transfer from the lower surface side of the thermal fuse body to the low melting point alloy element (temperature sensitivity). The total thickness is preferably 50% or less.

In order to manufacture the above-mentioned thermal fuse, an insulating film coated with an uncured mixed resin is placed on a work table with the coated surface facing upward, and a flux coated low melting point alloy element with a strip-shaped lead conductor is placed on the lower insulating film. , To secure the fixed state at the arrangement position with the adhesive force of the uncured mixed resin, then disposed on the lower disposed insulating film the uncured mixed resin coated insulating film with the coating surface facing down, The mixed resin can be cured in a state where the upper insulating film is pressed by a jig.
In order to reinforce the adhesion at the sealing interface, roughening is applied to the inner surface of the insulating film and the surface portion of the lead conductor that contacts the cured resin, and the curing accelerator is applied to the inner surface of the insulating film and the surface portion of the lead conductor that contacts the cured resin. For example, it is preferable to apply metal fine powder.
It is preferable that the surface of the upper and lower flux coating layers be parallel to the plane of the strip-shaped lead conductor and the strip-shaped lead conductor and the upper and lower films be parallel. Thus, the outer surface of the main body of the thermal fuse can be flattened and attached to a device to be protected, for example, a secondary battery cell.

  FIG. 3 shows the cutting operation state of the low-melting-point alloy element of the alloy-type thermal fuse according to the present invention. The low-melting-point alloy element accommodated in the cavity 50 secured with the cured resin 5 and the flux are melted. Then, the molten alloy is divided into 200 and 200, and the molten flux 30 bites between the divided parts, and the distance between the divided parts is increased. Thus, the flux is applied to the lower surface of the portion where the low melting point alloy element enters between the leading ends of the opposing lead conductors and the lower surface of the leading end portion of the lead conductor existing on the lower surface, thereby increasing the volume of the cavity 50. Therefore, the distance between the splits can be increased, the insulation distance between the splits can be sufficiently secured, and reliable current interruption can be guaranteed.

This is an alloy-type thermal fuse having the configuration shown in FIGS. 1-1 and 1-2. For the strip-shaped lead conductor, a Ni conductor with a thickness of 100 μm × width 2.3 mm with Au plated at the tip portion was used, and the distance between the opposing end faces of the lead conductor was 0.6 mm. For the low melting point alloy element, the composition 52In-48Bi was used, and the thickness at the center point was 170 μm. Rosin was used for the flux. Glass fiber epoxy resin films with a thickness of 120 μm and vertical and horizontal dimensions of 3.5 mm × 3.0 mm are used for the upper and lower insulating films, and an anaerobic curable resin (urethane methacrylate resin-based LOCTI manufactured by Henkel) is used for the mixed curable resin.
TE630) Using a mixture of 20 parts by volume and UV-curing resin (urethane acrylate resin-based LOCNTE3311 manufactured by Henkel) and 7 parts by volume, a curing accelerator (metal fine powder) is applied to the inner surface of the film and the surface of the lead conductor that contacts the resin. Then, the gap between the upper and lower films was filled with the mixture by the above manufacturing method with 0.5 mm, and ultraviolet rays were irradiated for a minute at an irradiation dose of 3000 mJ / mm ² or more.

[Comparative Example 1]
The example was the same as the example except that a urethane acrylate resin alone was used instead of the mixed resin.

[Comparative Example 2]
In contrast to the examples, a urethane methacrylate resin alone was used in place of the mixed resin, and the same as in the examples except that ultraviolet irradiation was not performed.

These example products and comparative example products were allowed to stand in a heating bath at a temperature of 80 ° C. for 1 hour, then immersed in an oil bath at a heating rate of 1 ° C./1 minute, and heated under a current of 0.1 A. When the oil temperature when the low melting point alloy element of the fuse was cut off was measured, it was not cut off even when the oil was heated up to 105 ° C. in the comparative example, compared to 90 ± 2 ° C. in the example.
This result shows that the flux of the comparative example was altered due to poor sealing, while the example product was stable in sealing and was suitable for a low melting point alloy element (melting point 89 ° C. of composition 52In-48Bi). It can be inferred that it was operated at temperature.

It is a perspective view which shows the alloy type thermal fuse which concerns on this invention. It is II sectional drawing in FIGS. 1-1. It is drawing which shows the low melting-point alloy element with a lead conductor used in this invention. It is drawing which shows the manufacturing method of a low melting-point alloy element with a lead conductor same as the above. 3 is a view showing an operating state of an alloy type thermal fuse according to the present invention.

Explanation of symbols

1 Lead conductor 2 Low melting point alloy element 3 Flux 4 Insulating film 5 Mixture of anaerobic curable resin and ultraviolet curable resin

Claims (5)

An alloy-type thermal fuse characterized in that a mixture of an anaerobic cured resin and an ultraviolet curable resin is used as the cured resin in a thermal fuse that seals the flux-coated low melting point alloy element with a cured resin. A low melting point alloy element is welded between the lead conductors, and flux is applied to the low melting point alloy element. An alloy-type thermal fuse, which is filled with a mixture with resin. 3. The alloy type thermal fuse according to claim 1, wherein the volume ratio of anaerobic curable resin: UV curable resin is 5: 1 to 5: 3. The alloy type thermal fuse according to any one of claims 2 to 3, wherein a curing accelerator is applied to at least one of the inner surfaces of the upper and lower insulating films and the lead conductor portions that are in contact with the resin mixture. The alloy mold according to any one of claims 1 to 4, wherein an intermediate layer having the same composition as the flux and having a higher melting point than the flux is provided on the surface of the flux-coated low-melting-point alloy element. Thermal fuse.

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