JP4269264B2 - Thin thermal fuse - Google Patents

Description

  The present invention relates to a thin thermal fuse.

Recently, secondary batteries with high energy density such as lithium ion secondary batteries and lithium polymer secondary batteries have been used as secondary power sources for portable electronic devices such as mobile phones and notebook computers.
In these secondary batteries, the heat generation temperature generated at the time of abnormality is high because of its large energy density.
Therefore, it is known to install a thin thermal fuse and prevent a serious accident by cutting off the battery energization circuit before reaching the high temperature.
For example, as in the battery pack shown in FIG. 9 , a thin thermal fuse P ′ is mounted on the side surface of the flat case 8 that houses the secondary battery, and the secondary battery can be disconnected from the load by the operation of the thermal fuse. The circuit board 81 is connected to the secondary battery.
In FIG. 9 , 1 'and 1' are flat lead conductors of thin thermal fuses, 82a and 82b are external electrodes of the battery pack, and the lead conductors and electrodes are connected by spot resistance welding or the like.
As this thin thermal fuse, a film type, a substrate type, a resin mold type and the like are known.
FIG. 10 (a) is a plan view partially showing an example of a conventionally known film type in section, and FIG. 10 (b) is a cross-sectional view in FIG. 10 (b).
In FIG. 10 , 41 'is a lower resin film, 1' and 1 'are a pair of flat lead conductors disposed on the lower resin film, and 2' is connected between the lead conductors 1 'and 1'. The molten alloy pieces 3 'are fluxes applied to the lead conductor portions on and near the soluble alloy pieces. Reference numeral 42 ′ denotes an upper resin film, and the periphery is sealed to the lower resin film 41 ′ and the flat lead conductor 1 ′ while being curved on the protruding coating flux 3 ′.

Plan view showing another example partly in section of (b) is a conventionally known film-type 11, (b) in FIG. 11 B in (b) of FIG. 11 - is a B cross-sectional view.
In FIG. 11 , 41 ′ is a lower resin film, 1 ′ and 1 ′ are a pair of flat lead conductors, the front half is fixed to the lower surface of the film 41 ′, and the tip 101 ′ is squeezed out. Appears on the top of the film. 2 ′ is a fusible alloy piece connected between the lead conductor appearing portions 101 ′ and 101 ′, 3 ′ is applied to the fusible alloy piece 2 ′ and the portion near the end of the fusible alloy piece of the conductor appearing portion 101 ′. It is flux. Reference numeral 42 ′ denotes an upper resin film, and the periphery is sealed to the lower resin film 41 ′ and the flat lead conductor 1 ′ while being curved on the protruding coating flux 3 ′.

(B) is a plan view showing a conventional resin mold type in Figure 12, in FIG. 12 (b) is B in (b) of FIG. 12 - is a B cross-sectional view.
In FIG. 12 , 1 'and 1' are flat lead conductors, 2 'is a fusible alloy piece connected between the flat lead conductors, 3' is applied to the fusible alloy piece and the lead conductor portion near the end of the fusible alloy piece. Flux. Reference numeral 40 'denotes a resin mold coating, which is provided by immersion coating of a curable resin liquid such as an epoxy resin.

Plan view showing an example partly in section of the (i) is known substrate type 13, (b) in FIG. 13 B in (b) of FIG. 13 - is a B cross-sectional view.
In FIG. 13 , 51 ′ is an insulating substrate such as a ceramic plate, 6 ′ and 6 ′ are a pair of electrodes provided on the insulating substrate, and 1 ′ and 1 ′ are flat surfaces connected to the electrodes 6 ′ and 6 ′. The lead conductor, 2 ′ is a fusible alloy piece connected between the electrodes 6 ′ and 6 ′, and 3 ′ is a fusible alloy piece and a flux applied from the end of the fusible alloy piece to the lead conductor tip. 52 ′ is a cover plate such as a ceramic plate, and 7 ′ is an adhesive for sealing the periphery of the cover plate 52 ′ to the insulating base 51 ′ and the flat lead conductor 1 ′, and on the protruding coating flux 3 ′. A cover plate 52 ′ is placed, and a two-component adhesive 7 ′ such as an epoxy resin is applied around the plate.

The operating mechanism of the thermal fuse is as follows.
The melting point of the fusible alloy piece 2 ′ is set so that the fusible alloy piece can be fused at a temperature sufficiently lower than the abnormal heat generation temperature with respect to the abnormal heat generation of the secondary battery.
Thus, when the fusible alloy piece is melted, the molten alloy is wetted and pulled on the electrode and the end of the lead conductor in the coexistence with the already melted flux, and the wetting is expanded by spheroidization and the molten alloy is melted. When the division is promoted and the current is cut off by the division and the heat generation of the battery is stopped, the divided molten alloy is solidified and the non-return cut-off is terminated.
The flux is soluble alloy by preventing oxidation of the easily oxidizable soluble alloy piece, dissolving the oxide inevitably contained in the soluble alloy piece by activation of the flux by heating, etc. It is indispensable to secure the space when the molten alloy is spheroidized, while the piece is melted accurately at a predetermined melting point and the surface energy surface promotes the wetting of the molten alloy to the electrode and the end of the lead conductor. In other words, a sufficient amount of flux needs to be present at the ends of the electrodes and lead conductors.

In the coating of the flux of the thermal fuse, usually, the liquid flux is heated and melted by attaching a predetermined outer, and cooled to solidify so as shown in (b) of FIG. 14. In this case, when considering the longitudinal section of the coating flux, as shown in (b) of FIG. 14, the surface tension r _m of the electrode or the _like, the surface tension of the r _L coagulation immediately preceding _flux, the flux and the electrode such as surface If the interfacial tension between and is r _mL and the contact angle is α,

r _m = r _L cos α + r _mL

The angle gradually decreases from the contact end to the center, the angle becomes 0 at the center, and the center height y increases as the distance x from the center to the contact end increases. Therefore, in order to coat the flux up to the end portion of the lead conductor, the center height y needs to be considerably increased.

In the above-mentioned film type thin thermal fuse, the upper resin film is curved and sealed on the protruding coating flux, so the thermal fuse body is warped and the connection point between the fusible alloy piece and the flat lead conductor Damage is a problem.
That is, the bending radius of the initial upper resin film in contact with the protruding coating flux in a curved state is r ′, the bending rigidity of the upper resin film is (EI) ′, and the bending rigidity of the thermal fuse body portion excluding the upper resin film is If (EI), the bending reaction force m acting on the thermal fuse body part is

  m = 1 / {r ′ [1+ (EI) ′ / (EI)]}

This bending reaction force m increases due to the large bending rigidity of the lead conductor, and a large peeling force acts on the connection interface between the flat lead conductor and the fusible alloy piece, thereby reducing the safety of the connection interface. Be inhibited.

  In the above-mentioned resin mold type thin thermal fuse, since a large amount of flux is applied to the upper surface side of the fusible alloy piece, it is unavoidable that the bending neutral surface is deviated from the thickness center surface of the flat lead conductor. The thermal fuse body is bent and deformed due to temperature changes based on the difference in linear expansion coefficient, cross-sectional area, and Young's modulus between the lead conductor and the lead conductor, but the bending reaction force acting on the lead conductor with high bending rigidity increases. Also in this case, a peeling force acts on the connection interface between the flat lead conductor and the soluble alloy piece, and the safety of the connection interface is hindered.

In contrast to these film type thin type thermal fuses and resin mold type thin type thermal fuses, the board type thin type thermal fuse has a large bending rigidity (EI), so even if a bending moment (M) acts, The bending radius of curvature (r = EI / M) can be kept sufficiently large, bending deformation can be substantially eliminated, and the above-described instability of the connecting portion between the soluble alloy piece and the lead conductor can be avoided.
However, in the flux application of the thermal fuse, the three-dimensional shape of the flux after cooling and solidification becomes a tall dome-shaped curved surface. Therefore, as shown in FIG. As long as the cover plate 52 'is placed, instability of the support state of the cover plate 52' is inevitable due to the contact between the curved surface and the flat surface, and the cover plate 52 'swings with respect to the long axis center line and loses balance. I can't escape tilting. Thus, as shown in FIG. 22B, the amount of flux with respect to the divided molten alloys 23a ′ and 23b ′ when the soluble alloy pieces spheroidize on both sides as shown in FIG. The spheroidization of the molten alloy on the side with less flux is made slower than the spheroidization of the molten alloy on the other side, resulting in a delay in the cutting operation. At this time, since the inclination angle of the insulating cover plate 52 ′ is different for each product, a variation in the dividing operation is caused.

As described above, it is necessary for a sufficient amount of flux to be present at the end of the electrode or lead conductor in the thermal fuse.
Conventionally, it has been known that a flat lead conductor portion in the vicinity of one end of a fusible alloy piece is projected by a punch, and this protruding portion is used as a weir for the coating flux to increase the flux coating thickness of the lead conductor portion in the vicinity of one end portion of the fusible alloy piece. (See Patent Document 1).

JP 2001-52582 A

However, in punching, it is necessary to increase the thickness of the flat lead conductor to prevent cracking. This makes it difficult to reduce the bending rigidity of the flat lead conductor, and this is in response to the bending reaction force in the film type and resin mold type described above. It is not suitable for avoiding destabilization of the connection point between the fusible alloy piece and the lead conductor.
Also, in punching, the protrusion width is narrower than the flat lead conductor width, and the corners of the protrusion outer surface are easily rounded, so it is difficult to eliminate the instability of the support state of the cover plate in the substrate type. In addition, the above-described problem of degradation of the severability due to the inclination of the cover plate cannot be solved.

  It is an object of the present invention to be able to sufficiently increase the thickness of the flux coating in the thin thermal fuse from the one end of the fusible alloy to the tip of the flat lead conductor and bend the film type or resin mold type thin thermal fuse. It can satisfactorily solve the destabilization problem of the connection point between the fusible alloy piece and the lead conductor based on the reaction force, and for the board-type thin thermal fuse, ensure uniform split spheroidization of the fusible alloy piece. It is to achieve smooth operation.

In the thin thermal fuse according to claim 1, the fusible alloy piece is connected between the flat lead conductors in a state where the thickness center of the fusible alloy piece is positioned above the thickness center of the flat lead conductor. And the lead conductor portion in the vicinity thereof is coated with flux, and these lead conductors are hermetically led out and sealed by the lower resin film and the upper resin film, and the upper resin film is on the protruding contents on the inner surface side. In the thermal fuse formed by bending at the lead conductor part between the one end of the fusible alloy and the film sealing part, the bending rigidity of the lead conductor part is lowered and the weir for the coating flux is formed. The projections are provided as weirs for the application of the flux.

In the thin thermal fuse according to claim 2, a pair of flat lead conductor end portions are fixed to the lower surface of the lower resin film, and a portion spaced a predetermined distance from the tip of each lead conductor has a predetermined width. Appeared on the upper surface of the film, and the exposed part was formed into a land part and a bent convex part for lowering the bending rigidity of the rear side of the land part and forming a weir against the coating flux . A fusible alloy piece is connected between the land portions, the flux is applied to almost the entire surface of the fusible alloy piece and the land portion with the bent convex portion as a weir, and the upper resin film is formed of the lower resin film. The upper resin film is sealed on the periphery and curved on the protruding contents on the inner surface side, and an auxiliary resin film is adhered to the lower surface of the lower resin film.

  According to a third aspect of the present invention, in the thin thermal fuse of any one of the first and second aspects, the upper resin film is made thinner than the lower resin film.

In the thin thermal fuse according to claim 4, the fusible alloy piece is connected between the flat lead conductors, and the flux is attached to the fusible alloy piece and the lead conductor portion at a predetermined distance from the end of the fusible alloy piece. In a thermal fuse that is surrounded and covered with a resin layer, a bent convex portion for reducing the bending rigidity of the lead conductor portion at a predetermined distance from one end of the fusible alloy and forming a weir against the applied flux Is provided, and this convex portion is a weir for the application of the flux.

  According to a fifth aspect of the invention, in the thin thermal fuse according to any one of the first to fourth aspects, the upper ends of both sides of the bent convex portion are rounded.

  According to a sixth aspect of the present invention, in the thin thermal fuse, the fusible alloy piece is connected between the flat lead conductors in a state where the thickness center of the fusible alloy piece is located above the thickness center of the flat lead conductor. In addition, the flux is attached to the lead conductor portion in the vicinity thereof, and these lead conductors are hermetically led out and sealed by the lower resin film and the upper resin film, and the upper resin film is on the protruding contents on the inner surface side. In the temperature fuse that is curved in the above, a bent convex portion is provided at the tip of the flat lead conductor, a soluble alloy piece end is connected to the front surface of the convex portion, and the convex portion serves as a weir for the application of the flux. It is characterized by.

  According to a seventh aspect of the invention, in the thin thermal fuse of the sixth aspect, the upper ends of both sides of the convex portion are rounded, and in an eighth aspect of the thin thermal fuse of the seventh or eighth aspect, the upper resin film is the lower resin. In the thin thermal fuse according to any one of claims 1 to 8, the width of the lead conductor portion in the thermal fuse body is made wider than the width of the fusible alloy piece. In the thin thermal fuse of claim 9, the lead conductor portion in the thermal fuse body is formed by rolling.

  In claim 11, in the thin thermal fuse of any one of claims 1 to 10, the lead conductor is made of Ni, and at least one of Sn, Cu, Ag, Au, or an alloy containing these as a main component at the tip portion. In the twelfth aspect, in the thin thermal fuse of any one of the first to eleventh aspects, a heating element for fusing the fusible alloy piece is attached.

The thin thermal fuse according to any one of claims 1 to 12, wherein the fusible alloy piece includes an In-Sn-Bi alloy, a Bi-Sn-Sb alloy, an In-Sn alloy, and an In-Bi alloy. , Bi—Sn alloy, In alloy, and the composition of the In—Sn—Bi alloy is (1) 43% <Sn ≦ 70%, 0.5% ≦ In ≦ 10%, the remaining Bi, (2) 25% ≦ Sn ≦ 40%, 50% ≦ In ≦ 55%, remaining Bi, (3) 25% <Sn ≦ 44%, 55% <In ≦ 74%, 1% ≦ Bi <20%, ( 4) 46% <Sn ≦ 70%, 18% ≦ In <48%, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In <37%, remaining Bi (however, Bi 57.5%, In 25.2%, Sn 17.3% and Bi 54%, In 29.7%, Sn 16.3% 2%, except In and Sn ± 1% range), (6) 10% ≦ Sn ≦ 18%, 37% ≦ In ≦ 43%, remaining Bi, (7) 25% <Sn ≦ 60%, 20% ≦ In <50%, 12% <Bi ≦ 33%, (8) Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P in any one of 100 parts by weight of (1) to (7) 0.01 to 7 parts by weight in total, (9) 33% ≦ Sn ≦ 43%, 0.5% ≦ In ≦ 10%, remaining Bi, (10) 47% ≦ Sn ≦ 3 to 5 parts by weight of Bi are added to 100 parts by weight of 49%, 51% ≦ In ≦ 53%, (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, remaining In, (12) 0.3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, remaining Bi, (13) 2.5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, remaining In, (14) (9 To one part or two or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P in a total of 0.01 to 7 parts by weight to any 100 parts by weight of (13), (15 ) 10% ≦ Sn ≦ 25%, 48% ≦ In ≦ 60%, remaining Bi is 100 parts by weight, one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P 0.01 to 7 parts by weight in total, the composition of the Bi—Sn—Sb alloy is (16) 30% ≦ Sn ≦ 70%, 0.3% ≦ Sb ≦ 20%, the remaining Bi, (17) (16 ) Is added in a total of 0.01 to 7 parts by weight of one or more of Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, P, and the composition of the In—Sn alloy is ( 18) 52% ≦ In ≦ 85%, remaining Sn, (19) Ag, Au, Cu, Ni, Pd in 100 parts by weight of (18) One or more of Pt, Sb, Ga, Ge, and P are added in a total of 0.01 to 7 parts by weight. The composition of the In—Bi alloy is (20) 45% ≦ Bi ≦ 55%, the remaining In, ( 21) A total of 0.01 to 7 parts by weight of one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P is added to 100 parts by weight of the composition of (20), Bi The composition of the Sn-based alloy is (22) 50% <Bi ≦ 56%, the remaining Sn, (23) and 100 parts by weight of (22) of Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, P One or two or more types are added in a total of 0.01 to 7 parts by weight, and the composition of the In-based alloy is (24) 100 parts by weight of In containing Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, P Add one or more kinds in total 0.01 to 7 parts by weight, (25) 90% ≦ In ≦ 99.9%, 0.1% ≦ Add one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P to 100 parts by weight of Ag ≦ 10% in total 0.01 to 7 parts by weight, (26) 95% ≦ In ≦ 99.9%, 0.1% ≦ Sb ≦ 5% 100 parts by weight of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, P or a total of 0 or more. Any of 01 to 7 parts by weight added is used.

  In the fourteenth aspect, the thin thermal fuse according to any one of the first to tenth aspects or the thirteenth aspect is used as a current fuse.

In the thermal fuse according to the present invention, the folding protrusion provided at the leading end portion of the lead conductor or the bending protruding portion provided at the leading end of the lead conductor can be used as a weir to allow the flux to adhere to the vicinity of one end of the fusible alloy. Therefore, the split spheroidization on both sides of the molten alloy can be caused quickly, and the rapid operation can be guaranteed.
In this case, even if the lead conductor is thin, the above-mentioned weir can be satisfactorily provided. Especially for the film type thin thermal fuse, the lead conductor of the bending reaction force generated based on the curved sealing of the upper resin film. Since the burden can be reduced by reducing the thickness of the lead conductor and reducing the bending rigidity, the joint interface between the lead conductor and the soluble alloy piece can be stably maintained, and stable operability can be guaranteed .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 (a) is a plan view showing a part of an embodiment of a thin thermal fuse according to the present invention in section, and FIG. 1 (b) is a cross-sectional view of FIG.
In FIG. 1, reference numerals 1 and 1 denote a pair of flat lead conductors, which are provided with a convex portion 11 by bending at a predetermined distance from the tip. Reference numeral 2 denotes a fusible alloy piece joined by welding or the like between the top surfaces of the tip portions of the flat lead conductors 1 and 1, and spot resistance welding, laser welding, or the like can be used for welding. Reference numeral 3 denotes a flux, which is attached to the portion of the fusible alloy piece 2 and the fusible alloy piece from the end of the lead conductor to the bent convex portion 11 of the lead conductor, and the convex portion 11 is used as a weir for the application of the flux. The flux coating thickness of the portion from the lead conductor to the bent convex portion 11 is made sufficiently thick. 41 is a lower resin film, and 42 is an upper resin film. The upper half of the flat lead conductors 1 and 1 and the soluble alloy piece 2 are sandwiched between these resin films 41 and 42, and the upper resin film 42 is formed. The peripheral portion is sealed to the lower resin film 41 that is horizontally held while being curved on the protruding coating flux 3.

FIG. 2 (a) is a plan view showing a part of another embodiment of the thin thermal fuse according to the present invention different from the above, and FIG. 2 (b) is a cross-sectional view of FIG. is there.
In FIG. 2, 41 is a lower resin film. Reference numerals 1 and 1 denote a pair of flat lead conductors, the front half of which is fixed to the lower surface of the lower resin film 41 and the upper surface thereof is substantially flush with the lower resin film surface at a predetermined distance from the tip of the lead conductor. The rear end portion of the convex portion 101 is bulged into the convex portion 11 at a stroke so as to appear on the upper surface side of the lower resin film 41, and the lower resin film 41 and the flat lead conductor 1 are All interfaces are joined by fusion or adhesive. Reference numeral 2 denotes a fusible alloy piece, which is connected to a portion 101 substantially flush with the upper surface of the lower resin film of the lead conductor appearing portion by welding, for example, spot resistance welding, laser welding or the like. Reference numeral 3 denotes a flux, which is attached to a portion from the fusible alloy piece 2 and the fusible alloy piece to the convex portion 11 of the lead conductor, and the convex portion 11 is used as a weir of the flux, and the lead from the fusible alloy piece 2 The flux coating thickness in the portion reaching the convex portion 11 of the conductor is made sufficiently thick. Reference numeral 42 denotes an upper resin film, which is sealed on the lower resin film 41 that is horizontally held in a state of being curved on the protruding coating flux 2.

  In the embodiment shown in FIG. 2, partial appearance of the lead conductor 1 on the upper surface of the lower resin film is performed by bulging, and both sides of the appearance are not processed. As shown in (a) (plan view) and (b) (roll cross-sectional view in (b) of FIG. 3), the upper surface is on the lower side to a position separated from the position near the tip of the lead conductor by a predetermined distance. The land 101a is substantially flush with the upper surface of the resin film 41, and the rear side is bulged into a convex portion 11a. The auxiliary resin film 43 is melted on the back surface of the lower resin film 41 to ensure water tightness. It can also be attached by adhesion or adhesive. Alternatively, as shown in (a) (plan view) and (b) of FIG. 4 (roro sectional view in (a) of FIG. 4), the upper surface extends to a position separated by a predetermined distance from the tip of the lead conductor. In order to ensure watertightness, the rear side of the lower resin film 41 is bent to a land portion 101b that is substantially flush with the upper surface of the lead conductor, and the rear side is bent into a bent convex portion 11b that extends over the entire width of the lead conductor. The auxiliary resin film 43 can also be adhered to the back surface of the resin film 41 by fusion or an adhesive.

  The auxiliary resin film 43 also has an effect of supplementing the lack of insulation strength between the lead conductor tips when the auxiliary resin film in FIG. 2 is not present.

  In the film-type thin thermal fuse shown in FIGS. 1 to 4, the fusible alloy piece 2 is positioned between the flat lead conductors 1, 1 with the thickness center of the fusible alloy piece 2 positioned above the flat lead conductor 1. Since the fusible alloy piece 2 is connected, the flux 3 is attached to the fusible alloy piece and the lead conductor portion in the vicinity thereof, and the upper resin film 42 is curved on the protruding contents on the inner surface side, so that warpage occurs. . In this case, the bending radius of the original upper resin film 42 in contact with the protruding coating flux in a curved state is r ′, the bending rigidity of the upper resin film 42 is (EI) ′, and the temperature fuse body portion excluding the upper resin film If the bending stiffness is (EI), the bending reaction force m acting on the thermal fuse body portion is as described above.

  m = 1 / {r ′ [1+ (EI) ′ / (EI)]}

Given in.
Therefore, the weir for the application of the flux 3 is provided by the bent convex portion 11, 11 a or 11 b of the flat lead conductor, and even if the flat lead conductor 1 is made as thin as 100 μm, the convex portion is simply bent. 11, 11a or 11b can be formed, and the occurrence of cracks can be eliminated. However, in the convex portion 11 of the embodiment shown in FIG. 2, the lead conductor 1 is processed at the same time when the lead resin 1 is bulged to the convex portion 101 on the upper surface of the lower resin film 41. Therefore, even if the lead conductor is made thin, cracks can be sufficiently prevented from occurring.
Therefore, the bending stiffness (EI) of the thermal fuse body portion can be reduced to reduce the bending reaction force m acting on the thermal fuse body portion, and the bonding interface between the flat lead conductor and the fusible alloy piece based on the bending reaction force m. It is possible to reduce the peeling force acting on the film and to increase the stability of the bonding interface.

  In the film-type thin thermal fuse shown in FIGS. 1 and 2, the upper resin film 42 is made thinner than the lower resin film 41 to reduce (EI) ′, thereby reducing the bending reaction force m. Therefore, the stability of the bonding interface can be further enhanced.

  In the film-type thin thermal fuse shown in FIGS. 3 and 4, (EI) ′ is reduced by making the upper resin film 42 thinner than the total thickness of the lower resin film 41 and the auxiliary resin film 43. It is possible to reduce the bending reaction force m and further improve the stability of the joint interface.

  In any of the above embodiments, the sealing between the resin films can be performed by high-frequency welding, ultrasonic welding, or an adhesive, and the sealing between the lead conductor and the resin film is performed by pressing the film outer surface under pressure. It can be performed by electromagnetic induction heating or heat plate contact heating.

FIG. 5 (a) is a plan view showing another embodiment of the thin thermal fuse according to the present invention, and FIG. 5 (b) is a cross-sectional view of FIG. 5 (b).
In FIG. 5, reference numerals 1 and 1 denote a pair of flat lead conductors, which are provided with a bent convex portion 11 at a position separated from the tip by a predetermined distance. Reference numeral 2 denotes a fusible alloy piece, which is connected between the lead conductor tips by welding, for example, spot resistance welding or laser welding. Reference numeral 3 denotes a flux, which is attached to the fusible alloy piece 2 and the portion extending from the fusible alloy piece 2 to the bent convex portion 11 of the lead conductor, and the convex portion 11 is used as a flux weir. The flux coating thickness in the portion from the end to the bent convex portion 11 of the lead conductor is made sufficiently thick. Reference numeral 40 denotes a resin coating layer that surrounds the fusible alloy piece, the flux, and the end portion of the lead conductor, and is coated by immersion coating in a two-component curable resin solution such as an epoxy resin solution.

  In the embodiment shown in FIG. 5, the Young's modulus of the flux is mechanically extremely small, so that it can be handled as a composite of the coating resin 40 and the soluble alloy piece 2-lead conductors 1 and 1, and on the coating resin side. The bending rigidity is (EI) ', the bending rigidity of the fusible alloy piece-lead conductor side is (EI), and the bending moment generated when the temperature changes due to the difference in Young's modulus, cross-sectional area, and thermal expansion coefficient of M Then, the bending moment m borne by the fusible alloy piece-lead conductor side is

  m = M / {1 + [(EI) '/ (EI)]}

Given in.
Therefore, the weir for the flux 3 is provided by the bent convex portion 11 of the flat lead conductor, and even if the thickness of the flat lead conductor 1 is as thin as 100 μm, the convex portion is bent by a simple bending process. Therefore, the bending moment m acting on the lead conductor can be reduced by reducing the bending rigidity (EI) on the side of the soluble alloy piece-lead conductor, and the flat lead conductor can be dissolved with the flat lead conductor based on the bending moment m. The peeling force acting on the bonding interface with the alloy piece can be reduced, and the stability of the bonding interface can be improved.

  In the above description, if the upper ends of both sides of the bent convex portion 11 are rounded, it is possible to eliminate concerns about local damage to the upper resin film when the upper end is an edge and local thinning due to a decrease in the surface tension of the coating resin.

6 (a) is a plan view showing a part of another embodiment of the thin thermal fuse according to the present invention different from the above, and FIG . 6 (b) is a cross-sectional view of FIG. 6 (a). is there.
In FIG. 6, reference numerals 1 and 1 denote a pair of flat lead conductors whose tips are processed into upward bent convex portions 110. Reference numeral 2 denotes a fuse element joined by welding or the like between the front surfaces of the upward bent convex portions 110 of both flat lead conductors 1 and 1, and laser welding or the like can be used. Reference numeral 3 denotes a flux, which uses the upward bent convex portion 110 at the tip of the lead conductor as a flux weir to sufficiently increase the flux coating thickness. 41 is a lower resin film, and 42 is an upper resin film. The upper half of the flat lead conductors 1 and 1 and the fuse element 2 are sandwiched between these resin films 41 and 42, and the upper resin film 42 is projected. The periphery is sealed to the lower resin film 41 that is horizontally held in a state of being curved on the coating flux 3.

In the embodiment shown in FIG. 6 , the weir 110 for the flux 3 is provided by upward bending of the tip of the flat lead conductor, and even if the thickness of the flat lead conductor is as thin as 100 μm, it is a simple bending process. Occurrence can be eliminated. Accordingly, similarly to the embodiment shown in FIG. 1, the bending stiffness (EI) of the thermal fuse body portion can be reduced to reduce the bending reaction force m acting on the thermal fuse body portion. The peeling force acting on the joint interface between the lead conductor and the soluble alloy piece can be reduced, and the stability of the joint interface can be enhanced.

Also in the embodiment shown in FIG. 6 , the thickness of the upper resin film 42 can be made thinner than the thickness of the lower resin film 41.

  In the above, if the upper ends of both sides of the upward bent convex portion 110 of the lead conductor tip are rounded, local damage to the upper resin film when the upper end is an edge, and local thinning due to a decrease in the surface tension of the coating resin Can dispel concerns.

  In addition to the resin mold type thermal fuse according to the present invention, the fusible alloy piece end is connected to the front surface of the upward bent convex part of the lead conductor tip by welding or the like in addition to the one shown in FIG. It can also be carried out by providing a resin coating layer surrounding the end portion of the lead conductor, for example, an epoxy resin coating layer.

  In the present invention, the width of the thermal fuse body can be made equal to or smaller than the width of the lead conductor portion outside the thermal fuse body. Further, it is desirable that the sealing allowance between the resin films and the sealing allowance of the insulating cover plate to the insulating base are made as large as possible at the both ends of the temperature fuse body. In this case, as shown in FIG. 14A, the width w1 of the lead conductor portion inside the thermal fuse body can be made narrower than the width w2 of the lead conductor portion outside the thermal fuse body.

  In the present invention, in order to adhere the flux, the flux is heated and melted to adhere to the outer shell including the soluble alloy piece, and this adhesion flux is cast to reach the weir under the action of surface tension and interfacial tension. And solidify by natural cooling. In this case, the width of the lead conductor portion in the temperature fuse body is made wider than the width of the fusible alloy piece so that the width of the convex portion as a weir against the flux is wider than the width of the fusible alloy piece. The flux having a width including the half width is satisfactorily blocked by the convex portion.

The flat lead conductor only needs to have a flat lead conductor portion inside the thermal fuse body. The flat lead conductor is flat as a whole, and the width of the inner conductor portion is w1, as shown in FIG. The width is w2, w1 <w2, w1 = w2 as shown in FIG. 7B, and w1> w2 as shown in FIG. As shown in 7 (d), it is also possible to use the one in which the first half of the round wire rod is rolled and this rolled portion is used as the inner lead conductor portion. The same applies to the case where the convex portion 11 is provided by bending.
The upward bending convex portion 110 at the tip of the flat lead conductor may be subjected to ancillary processing as long as it can connect one end of a fusible alloy and can serve as a weir against the flux. It is also possible to add a horizontal hook portion 1101 as shown in (e) or a folded portion 1102 as shown in (f) of FIG.
In addition, the bent convex portion 11 is usually a triangular convex portion as shown in FIG. 7G, but a rectangular convex portion as shown in FIG. 7H, as shown in FIG. It can also be a trapezoidal convex part.
In addition, as shown in FIG. 7 (n), it is possible to use one provided with a convex portion 1100 by cutting and bending.

    Although Cu, Fe, or the like can be used for the lead conductor, it is preferable to use Ni which is easy to weld, particularly spot resistance welding. In addition, at least the tip of the lead conductor is mainly made of Sn, Cu, Ag, Au, or a metal thereof for the purpose of facilitating welding with a fusible alloy piece and facilitating welding with an electrode. It is preferable to coat the alloy as a component. In particular, in the case of a Ni lead conductor, the Sn coating relaxes the thermal shock at the nugget in terms of heat and stress when it is fixed to the electrode by spot resistance welding, thus ensuring the prevention of cracks in the ceramic insulating substrate. It is valid.

  As the above upper resin film, lower resin film and auxiliary resin film, polyethylene terephthalate is suitable, but polyethylene naphthalate, polyamide, polyimide, polybutylene terephthalate, polyphenylene oxide, polyethylene sulfide. Engineering plastics such as polysulfone, polyacetal, polycarbonate, polyphenylene sulfide, polyoxybenzoyl, polyetheretherketone, polyetherimide, etc., polypropylene, polyvinyl chloride, polyvinyl acetate, polymethyl Methacrylate, polyvinylidene chloride, polytetrafluoroethylene, ethylene polytetrafluoroethylene copolymer, ethylene vinyl acetate copolymer (EVA), AS resin, ABS Fat, ionomer -, AAS resins, films of thermoplastic resins such as ACS resins can also be used.

  The electrode is formed by applying or baking a conductive foil such as Ag paste, Cu paste, Au paste, Pt paste, Ag-Pt paste, Ag-Pd paste, or printing / etching the metal foil of the metal foil laminated insulating substrate. It can also be formed.

A round wire or a rolled wire can be used for the soluble alloy piece, and the width of the rolled wire can be made substantially equal to the width of the tip of the flat lead conductor.
The melting point of the fusible alloy piece is selected according to the protection temperature of the device, but for batteries, an alloy having a solidus temperature of 80 ° C to 120 ° C and a liquidus temperature of 90 ° C to 120 ° C is used. Is done. For example, In50 to 55%, Sn25 to 40%, remaining Bi alloy, In30 to 75%, Sn5 to 50%, Cd0.5 to 25% alloy, and the alloy composition of Cu, Ag, Au, Al, Bi Alloy in which one or more of them are added in a total of 0.1 to 5%, Bi 48 to 53%, Pb 28 to 33%, Sn 13 to 19% alloy, In 0.5 to 4%, Bi 50 to 54%, Pb 30 An alloy of ˜34% and Sn14˜18% can be exemplified.
The fusible alloy piece can be produced by a drawing method or drawing method in which a rod is obtained by casting or extruding a base material, the rod is drawn, and further rolled. In addition, the rotating liquid spinning method is used in which the cooling liquid in the drum is layered by rotating the drum, and the molten alloy jet from the nozzle enters the rotating liquid layer at the same speed as the peripheral speed of the rotation to cool and solidify. You can also

  Recently, as a soluble alloy piece, it has been required to use a composition containing no harmful metal in a biological system such as Pb or Cd for environmental hygiene. The drawing method or the drawing rolling method or the rotation method satisfies this requirement. The composition that can be produced by the spinning method is [A] (1) 43% <Sn ≦ 70%, 0.5% ≦ In ≦ 10%, remaining Bi, (2) 25% ≦ Sn ≦ 40%, 50 % ≦ In ≦ 55%, remaining Bi, (3) 25% <Sn ≦ 44%, 55% <In ≦ 74%, 1% ≦ Bi <20%, (4) 46% <Sn ≦ 70%, 18% ≦ In <48%, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In <37%, remaining Bi (Bi57.5%, In25.2%, Sn17. Range of Bi ± 2%, In and Sn ± 1% based on 3%, Bi54%, In29.7% and Sn16.3% respectively (6) 10% ≦ Sn ≦ 18%, 37% ≦ In ≦ 43%, remaining Bi, (7) 25% <Sn ≦ 60%, 20% ≦ In <50%, 12% <Bi ≦ 33 %, (8) One or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P are added to 100 parts by weight of any one of (1) to (7) in a total of 0.01. ˜7 parts by weight added, (9) 33% ≦ Sn ≦ 43%, 0.5% ≦ In ≦ 10%, remaining Bi, (10) 47% ≦ Sn ≦ 49%, 51% ≦ In ≦ 53% 100 3 to 5 parts by weight of Bi is added to parts by weight, (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, remaining In, (12) 0.3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, remaining Bi, (13) 2.5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, remaining In, (14) any one of (9) to (13) 100 weight In addition, one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P are added in a total of 0.01 to 7 parts by weight, (15) 10% ≦ Sn ≦ 25%, 48 % ≦ In ≦ 60%, adding 100 parts by weight of the remaining Bi to one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P in a total of 0.01 to 7 parts by weight In-Sn-Bi based alloy composition [B] (16) 30% ≦ Sn ≦ 70%, 0.3% ≦ Sb ≦ 20%, remaining Bi, (17) to 100 parts by weight of (16) Composition [C] of Bi—Sn—Sb-based alloy such as Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, P or a total of 0.01 to 7 parts by weight of one or more added. 18) 52% ≦ In ≦ 85%, remaining Sn, (19) Ag, Au, Cu, Ni, Pd, Pt, Sb, 100 parts by weight of (18) In-Sn based alloy composition [D] (20) 45% ≦ Bi ≦ 55%, remaining In, (addition of 0.01 to 7 parts by weight in total of one or more of a, Ge, P) 21) A total of 0.01 to 7 parts by weight of one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P is added to 100 parts by weight of the composition of (20), etc. [E] (22) 50% <Bi ≦ 56%, remaining Sn, (23) In 100 parts by weight of (22), Ag, Au, Cu, Ni, Pd, Pt, Ga , Ge, P, or a total of 0.01 to 7 parts by weight of Bi-Sn based alloy composition [F] (24) In 100 parts by weight of In, Au, Bi, Cu, Ni , Pd, Pt, Ga, Ge, P, or a total of 0.01 to 7 parts by weight of one or more of them, (25) 90% ≦ In ≦ 99.9%, Add one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P to 100 parts by weight of 0.1% ≦ Ag ≦ 10% in total 0.01 to 7 parts by weight, (26) One or two of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P in 100 parts by weight of 95% ≦ In ≦ 99.9% and 0.1% ≦ Sb ≦ 5% The composition of In-based alloys such as a total addition of 0.01 to 7 parts by weight can be mentioned above, and it is preferable to select a composition having a melting point suitable for the operating temperature of the thermal fuse.

  The above flux includes natural rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) and purified rosin, diethylamine hydrochloride, diethylamine hydrobromide, organic acids such as adipic acid, etc. Can be used.

  An epoxy resin is usually used for the adhesive, but a curable resin such as a phenol resin or polyurethane can also be used.

The dimensions of the lower resin film, the upper resin film, and the auxiliary resin film are usually 5.0 to 15.0 mm for the long side and 3.0 to 5.0 mm for the short side. The thickness of the lower resin film is 0.2 to 0.4 mm, and the thickness of the upper resin film is equal to the thickness of the lower resin film or 50 μm to 80 μm.
As for the dimensions of the lead conductor, the width of the outer portion is usually 2.0 to 4.0 mm, and the width of the inner portion is 1.0 to 3.0 mm. The thickness of the lead conductor is 0.15 to 0.3 mm for the substrate type, and 0.07 to 0.15 mm for the film type and the resin mold type.

  The thermal fuse according to the present invention can be used for a secondary battery. For example, as shown in FIG. 9, it can be mounted on the side surface of the flat case of the secondary battery pack and inserted in series between the battery and the load. Therefore, when an abnormality occurs in the battery and the melting alloy piece of the thermal fuse reaches a melting point temperature, for example, a predetermined temperature within 80 ° C. to 100 ° C. due to the heat generation of the battery, the fusible alloy piece is blown, Is electrically interrupted, and the subsequent temperature rise of the battery is stopped. Therefore, abnormal heat generation of the battery can be prevented in advance.

In the above, when the Joule heat generation of the fusible alloy piece can be ignored, the temperature Tx of the fusible alloy piece when the battery reaches the allowable temperature Tm is 2 ° C. to 3 ° C. lower than Tm, and the melting point of the fusible alloy piece May be set to [Tm− (2 ° C. to 3 ° C.)].
However, when the Joule heating of the fusible alloy piece cannot be ignored, if the electric resistance of the fusible alloy piece is R, the energization current is I, and the thermal resistance between the device and the fuse element is H,

Tx = Tm− (2 ° C. to 3 ° C.) + HRI ²

It is effective to set the melting point of the fusible alloy piece based on the above equation.

In the thermal fuse according to the present invention, an energization heating element is attached, and a film resistance is attached by, for example, applying and baking a resistance paste (for example, a paste of metal oxide powder such as ruthenium oxide), which causes abnormal heat generation of the battery. It is also possible to detect an anomaly such as an abnormal increase in battery voltage during overcharging, and to generate heat by energizing the membrane resistance with this detection signal.
For example, the above-mentioned film resistance is provided on the upper surface of the insulating base, a heat-resistant and heat-conductive insulating film such as a glass baking film is formed thereon, a pair of electrodes is provided, and an upward bending convex portion is provided at the tip. A flat lead conductor is connected to each electrode, a fusible alloy piece is connected between both electrodes, a flux is coated from the fusible alloy piece to the tip convex portion of the lead conductor, and an insulating cover plate is placed on the insulating base. It is possible to dispose and seal the periphery of the insulating cover plate to the insulating substrate with an adhesive.

  FIG. 8 is a circuit diagram showing a use state of a thermal fuse with a heating element, P is a thermal fuse, 2 is a fusible alloy piece, R is a resistor, IC is an abnormal voltage detection energizing circuit, and D is a Zener. A diode, Tr represents a transistor, E represents a battery, and S represents a charger. When the battery voltage rises due to overcharging, Zener diode D is turned on and transistor Tr is turned on to cause current to flow through resistor R. The fusible alloy piece 2 is melted by the heat generated by the resistor R. The abnormal voltage detection energization circuit is formed on a circuit board attached to the battery pack.

2 is a film-type thin fuse having the configuration shown in FIG. For the lower resin film 41 and the upper resin film 42, a polyethylene terephthalate film having a long side of 7.3 mm, a short side of 3.4 mm, and a thickness of 188 μm was used. The flat lead conductor 1 has a thickness of 100 μm, a distance of 2.3 mm from the lead conductor tip to the bent convex part 11, a height of the convex part 11 of 0.50 mm, an inner part width of 2.6 mm, and an outer part width of 3.5 mm. A Ni conductor with a Cu film coated on the tip was used, and the distance between the lead conductors was 0.8 mm. The fusible alloy piece 2 is composed of a round wire having a composition of In52% -Sn36% -Bi12%, a diameter of 0.3 mm and a length of 4.4 mm, and the flux 3 is composed mainly of rosin. Then, the heat-melted material was cast between the protrusions 11 and 11 of both lead conductors 1 and 1, and cooled and solidified.
Sealing between the films was performed by ultrasonic welding, and fusion between the lead conductor and the film was performed by electromagnetic induction heating under pressure of a ceramic chip.

[Comparative Example 1]
In contrast to Example 1, an attempt was made to form a convex portion by punching instead of bending the convex portion of the lead conductor. However, since a crack occurred in the lead conductor having a thickness of 100 μm, the lead conductor thickness was set to 300 μm and the convex portion was formed by punching. (The height is the same as the height of the bent protrusion in Example 1). The rest was the same as Example 1.

When the resistance value between the lead conductors was measured with the number of samples of Example 1 and Comparative Example 1 being 50, the standard deviation was calculated and the dispersion degree was evaluated. As a result, the variation in the resistance value of Example 1 was Comparative Example 1. It became clear that it was remarkably small compared to.
From this result, both the example and the comparative example are common in that weirs are provided to increase the flux thickness, but in the example, the lead conductor can be made thin and generated based on the curved sealing of the upper resin film. Therefore, it can be confirmed that the joint interface between the lead conductor and the fusible alloy piece can be stably maintained, and the resistance value of the interface can be stably maintained.

  The same as Example 1 except that the thickness of the upper resin film was reduced to 125 μm with respect to Example 1.

When the resistance value between the lead conductors was measured with 50 samples in Example 2 and the standard deviation was calculated to evaluate the dispersion, it was equal to or greater than the resistance value variation in Example 1. There was found.
This result is because the warp generated based on the curved sealing of the upper resin film can be made smaller than in Example 1, and the interface resistance value is further stabilized by stabilizing the joint interface between the lead conductor and the soluble alloy piece. Maintenance can be expected.

3 is a film-type thin fuse having the configuration shown in FIG. The lower resin film 41 is a polyethylene terephthalate film having a long side of 7.3 mm, a short side of 3.4 mm, and a thickness of 188 μm. The upper resin film 42 has the same outer shell as the lower resin film and has a thickness of 125 μm. A terephthalate film was used. The flat lead conductor 1 has a thickness of 100 μm, a surface of the lower resin film that is flush with the exposed portion 101 and the distance from the lead conductor tip to the bent convex portion 11, the height of the convex portion 11 is 0.6 mm, the inner side A Ni conductor having a part width of 2.6 mm and an outer part width of 3.5 mm and having a Cu film coated on the tip including the exposed part was used, and the distance between the tips of both lead conductors was set to 0.8 mm. The fusible alloy piece 2 is composed of a round wire having a composition of In52% -Sn36% -Bi12%, a diameter of 0.3 mm and a length of 4.4 mm, and the flux 3 is composed mainly of rosin. Then, the heat-melted flux was cast between the convex portions 11 of both lead conductors and cooled and solidified.
The interface between the lead conductor and the lower resin film was thermally welded, and the films were sealed by ultrasonic welding.

  When the resistance value between the lead conductors was measured with 50 samples in Example 3, the standard deviation was calculated, and the degree of dispersion was evaluated, it was found to be equivalent to the variation in resistance value in Example 2. did.

It is a resin mold type thin fuse of the structure shown in FIG. The flat lead conductor 1 has a thickness of 100 μm, a distance of 2.3 mm from the lead conductor tip to the bent convex part 11, a height of the convex part 11 of 0.50 mm, an inner part width of 2.6 mm, and an outer part width of 3.5 mm. A Ni conductor with a Cu film coated on the tip was used, and the distance between the lead conductors was 0.8 mm. The fusible alloy piece 2 is composed of a round wire having a composition of In 52% -Sn 36% -Bi 12%, a diameter of 0.3 mm, and a length of 4.4 mm. The flux that was used and heated and melted was cast between the convex portions 11 and 11 of both lead conductors and cooled and solidified.
The resin mold coating layer 40 was provided by dip coating with a room temperature curing epoxy resin solution.

[Comparative Example 2]
In contrast to Example 4, an attempt was made to form a convex portion by punching instead of bending the convex portion of the lead conductor. However, since a crack occurred in the lead conductor having a thickness of 100 μm, the lead conductor thickness was set to 300 μm and the convex portion was formed by punching. (The height is the same as the height of the bent convex portion of Example 4). The rest was the same as in Example 4.

The number of samples in Example 4 and Comparative Example 2 was set to 50, and after a predetermined heat cycle test, the resistance value between the lead conductors was measured, the standard deviation was calculated, and the dispersion degree was evaluated. It was found that the variation in resistance value was significantly smaller than that of Comparative Example 2.
From this result, although Example 4 and Comparative Example 2 are common in that weirs are provided in order to increase the flux thickness, in Example 4, the thickness of the lead conductor can be reduced, and bending caused based on the heat cycle is generated. Since the moment of the lead conductor action can be reduced, it can be confirmed that the joint interface between the lead conductor and the soluble alloy piece can be stably maintained, and the resistance value of the interface can be stably maintained.

  The above-described temperature fuse can also be used as a thin current fuse that cuts off energization by fusing a fusible alloy piece by self-heating by energization.

1 is a view showing an embodiment of a thermal fuse according to the present invention. It is drawing which shows the Example different from the above of the thermal fuse which concerns on this invention. It is drawing which shows the Example different from the above of the thermal fuse which concerns on this invention. It is drawing which shows the Example different from the above of the thermal fuse which concerns on this invention. It is drawing which shows the Example different from the above of the thermal fuse which concerns on this invention. It is drawing which shows the Example different from the above of the thermal fuse which concerns on this invention. It is drawing which shows many examples from which the flat lead conductor used in this invention differs. It is a circuit diagram which shows the action | operation mechanism of the Example with a heat generating body among the thermal fuses which concern on this invention. 1 is a view showing a battery pack to which a thermal fuse according to the present invention is attached. It is drawing which shows an example of the conventional thin temperature fuse. It is drawing which shows an example different from the above of the conventional thin-type thermal fuse. It is drawing which shows an example different from the above of the conventional thin-type thermal fuse. It is drawing which shows an example different from the above of the conventional thin-type thermal fuse. 6 is a view showing the shape of a flux of a conventional thin thermal fuse. 6 is a diagram used for explaining a problem of a conventional thermal fuse.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat lead conductor 11 Bending convex part 110 Upward bending convex part 2 Soluble alloy piece 3 Flux 41 Lower resin film 42 Upper resin film 43 Auxiliary film 51 Insulating base 52 Insulating cover 53 Watertight resin coating 6 Electrode 7 Adhesive

Claims (14)

The fusible alloy piece is connected between the flat lead conductors in a state where the thickness center of the fusible alloy piece is located above the flat lead conductor, and flux is applied to the fusible alloy piece and the lead conductor part in the vicinity thereof. In a thermal fuse in which the lead conductor is hermetically led and sealed by a lower resin film and an upper resin film, and the upper resin film is curved on the protruding contents on the inner surface side. The lead conductor portion between the one end of the molten alloy and the film sealing portion is provided with a bending convex portion for reducing the bending rigidity of the portion and forming a weir against the coating flux, and this convex portion is applied with the flux. Thin thermal fuse characterized by being a weir against. Lower lower surface portion at a predetermined distance from the tip of the lead conductors with a pair of flat lead conductors end is fixed in the resin film is to appear on the film top surface having a predetermined width, the revealing The part is formed into a land part and a bent convex part for lowering the bending rigidity on the back side of the land part and forming a weir against the coating flux, and a soluble alloy piece is connected between the land parts that appear. The flux is applied to almost the entire surface of the fusible alloy piece and the land portion with the bent convex portion as a weir, and the upper resin film is sealed around the lower resin film and the upper resin film Is a thin thermal fuse characterized in that it is curved on the protruding contents on the inner surface side and an auxiliary resin film is adhered to the lower surface of the lower resin film. The thin thermal fuse according to claim 1, wherein the upper resin film is thinner than the lower resin film. A temperature at which a fusible alloy piece is connected between the flat lead conductors, the flux is adhered to the fusible alloy piece and the lead conductor portion at a predetermined distance from the end of the fusible alloy piece, and the resin layer is covered by surrounding the flux. In the fuse, a lead convex portion spaced apart from one end of the fusible alloy by a predetermined distance is provided with a bent convex portion for lowering the bending rigidity of the portion and forming a weir against the applied flux. Thin thermal fuse, characterized by being a weir against the application of copper. The thin thermal fuse according to any one of claims 1 to 4, wherein the upper ends of both sides of the bent convex portion are rounded. The fusible alloy piece is connected between the flat lead conductors in a state where the thickness center of the fusible alloy piece is located above the thickness center of the flat lead conductor, and flux is applied to the fusible alloy piece and the lead conductor part in the vicinity thereof. In a thermal fuse in which the lead conductor is hermetically led and sealed by a lower resin film and an upper resin film, and the upper resin film is curved on the protruding contents on the inner surface side thereof, A thin thermal fuse characterized in that an upward bent portion is provided at the tip of the lead conductor, a soluble alloy piece end is connected to the front surface of the bent portion, and the bent portion serves as a weir against the application of the flux. The thin thermal fuse according to claim 6, wherein the upper ends of both sides of the convex portion are rounded. The thin thermal fuse according to claim 6 or 7, wherein the upper resin film is thinner than the lower resin film. The thin thermal fuse according to any one of claims 1 to 8, wherein the flat lead conductor is a conductor in which the width of the lead conductor portion in the temperature fuse body is wider than the width of the fusible alloy piece. The thin thermal fuse according to claim 9, wherein a lead conductor portion in the thermal fuse body is formed by rolling. The thin thermal fuse according to any one of claims 1 to 10, wherein the lead conductor is made of Ni, and at least a tip portion thereof is coated with any one of Sn, Cu, Ag, Au, or an alloy containing these as a main component. The thin thermal fuse according to any one of claims 1 to 11, further comprising a heating element for fusing the fusible alloy piece. The soluble alloy piece is one of an In—Sn—Bi alloy, a Bi—Sn—Sb alloy, an In—Sn alloy, an In—Bi alloy, a Bi—Sn alloy, and an In alloy, and In— The composition of the Sn—Bi alloy is (1) 43% <Sn ≦ 70%, 0.5% ≦ In ≦ 10%, remaining Bi, (2) 25% ≦ Sn ≦ 40%, 50% ≦ In ≦ 55% , Remaining Bi, (3) 25% <Sn ≦ 44%, 55% <In ≦ 74%, 1% ≦ Bi <20%, (4) 46% <Sn ≦ 70%, 18% ≦ In <48%, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In <37%, remaining Bi (however, Bi57.5%, In25.2%, Sn17.3% and Bi54%, (Excluding Bi ± 2%, In and Sn ± 1% ranges based on In29.7% and Sn16.3%), (6) 10% ≦ Sn ≦ 18 %, 37% ≦ In ≦ 43%, remaining Bi, (7) 25% <Sn ≦ 60%, 20% ≦ In <50%, 12% <Bi ≦ 33%, (8) (1) to (7) One or two or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge and P are added in a total of 0.01 to 7 parts by weight to any 100 parts by weight of (9) 33% ≦ Sn ≦ 43%, 0.5% ≦ In ≦ 10%, remaining Bi, (10) Add 3 to 5 parts by weight of Bi to 100 parts by weight of 47% ≦ Sn ≦ 49% and 51% ≦ In ≦ 53% (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, remaining In, (12) 0.3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, remaining Bi, ( 13) 2.5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, remaining In, (14) Ag, Au, Cu, Ni, Pd, 100 parts by weight of any one of (9) to (13) One or more of t, Sb, Ga, Ge, and P are added in a total of 0.01 to 7 parts by weight, (15) 10% ≦ Sn ≦ 25%, 48% ≦ In ≦ 60%, and the remaining Bi is 100 Add one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P to 0.01 parts by weight in total, and the composition of the Bi-Sn-Sb alloy is (16) 30% ≦ Sn ≦ 70%, 0.3% ≦ Sb ≦ 20%, remaining Bi, (17) Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge in 100 parts by weight of (16) In addition, 0.01 to 7 parts by weight of one or more of P are added, and the composition of the In—Sn alloy is (18) 52% ≦ In ≦ 85%, the remaining Sn, (19) 100 of (18) One or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P in the weight part is a total of 0.01 to Addition of parts by weight, the composition of the In—Bi alloy is (20) 45% ≦ Bi ≦ 55%, the remaining In, (21) and 100 parts by weight of the composition of (20), Ag, Au, Cu, Ni, Pd, Pt , Sb, Ga, Ge, P are added in a total of 0.01 to 7 parts by weight, and the composition of the Bi—Sn alloy is (22) 50% <Bi ≦ 56%, the remaining Sn, (23 ) Addition of one or more of Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, P to 0.01 to 7 parts by weight to 100 parts by weight of (22), the composition of the In-based alloy is (24) A total of 0.01 to 7 parts by weight of one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P is added to 100 parts by weight of In, (25) 90% ≦ Au, Bi, Cu, Ni, Pd, Pt, 100 parts by weight of In ≦ 99.9%, 0.1% ≦ Ag ≦ 10% , Ga, Ge, P or one or more of 0.01 to 7 parts by weight in total, (26) 100% by weight of 95% ≦ In ≦ 99.9%, 0.1% ≦ Sb ≦ 5% A total of 0.01 to 7 parts by weight of one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P is added. Any one of the thin thermal fuses. 14. A thin current fuse, wherein the thin temperature fuse according to claim 1 is used as a current fuse.

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