JP2000133102A - Thin composite fuse and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a thin composite fuse comprising a thermal fuse and an electrical current fuse facilitating manufacture by utilizing lead frames. SOLUTION: A lead frame L where the tips of a pair of strip lead conductors 2, 2 and the both sides of an intermediate electrode 3 are connected with an outer frame (a) are used. After the intermediate electrode and the tip of one strip lead conductor is connected with a thermal fuse element 5 the both sides of the intermediate electrode 3 is separated from the outer frame (a). Then, an insulated support body (plastic film) 11 is stuck across the intermediate electrode 3 and the tips of the both strip lead conductors, and the intermediate electrode 3 and the tip of the other strip lead conductor are connected with an electric current fuse element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin composite fuse in which a temperature fuse and a current fuse are combined, and is useful for, for example, maintenance of small equipment such as a lithium ion secondary battery.

[0002]

2. Description of the Related Art Recently, rechargeable and rechargeable secondary batteries have been used as power sources for portable telephones, PHSs, video cameras, portable personal computers, and the like. Are widely used because of their high life, long life cycle, and high operating voltage. In this lithium ion secondary battery, if an internal short circuit occurs, its high energy is released at once, and the battery is exposed to a dangerous state. Therefore, it is safe to incorporate a current fuse into the battery pack. Further, there is a fear that an excessive temperature rise which is difficult to detect with the current fuse due to an abnormal chemical reaction in the battery may occur, and it is safe to incorporate the temperature fuse into the battery pack. In this case, in order to reduce the size of the battery pack, a thin composite fuse in which the temperature fuse and the current fuse are compactly combined is required. As is well known,
In some cases, a lead frame is used for manufacturing a semiconductor chip with a lead conductor.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin composite fuse in which a temperature fuse and a current fuse are combined and which can be easily manufactured using a lead frame. To provide a method for producing the same.

[0004]

According to a method of manufacturing a thin composite fuse according to the present invention, an intermediate electrode and a pair of strip-shaped lead conductors sandwiching the intermediate electrode are fixed on an insulating support plate. A temperature fuse element is connected between the intermediate electrode and the tip of one of the strip-shaped lead conductors, and a current fuse element is connected between the intermediate electrode and the tip of the other strip-shaped lead conductor. A method of manufacturing a composite fuse in which a support plate is sealed with a sealing material, wherein a rear end of the pair of strip-shaped lead conductors and both sides of the intermediate electrode are connected to an outer frame. After connecting the intermediate electrode and the tip of one of the strip-shaped lead conductors with a temperature fuse element, both sides of the intermediate electrode are separated from the outer frame, and then the insulating support plate is connected to the intermediate electrode and both strips. The lead wire is fixed over the leading end of the lead conductor.

In the thin composite fuse according to the present invention, an intermediate electrode and a pair of strip-shaped lead conductors sandwiching the intermediate electrode are fixed on an insulating support plate, for example, on the insulating support plate. A temperature fuse element is connected between one end of the strip-shaped lead conductor, and a current fuse element is connected between the intermediate electrode and the other end of the strip-shaped lead conductor. Is a composite fuse in which the temperature fuse element is provided with a bending stiffness capable of supporting the intermediate electrode at the tip of one of the strip-shaped lead conductors with respect to its own weight. This is a characteristic configuration.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a drawing showing a thin composite fuse manufactured according to the present invention, and FIG. 1B is a cross-sectional view of FIG. In FIG. 1, reference numeral 11 denotes an insulating support plate, and reference numeral 3 denotes an intermediate electrode fixed to the middle of the insulating support plate by an adhesive or fusion.
Reference numerals 2 and 2 denote a pair of strip-shaped leads arranged with the intermediate electrode 3 interposed therebetween.
Each of the strip-shaped lead conductor tips 20 is fixed to the insulating support plate 11 with an adhesive or fusion. 4 is a current fuse element connected between the intermediate electrode 3 and one end of the strip-shaped lead conductor 20, and 5 is connected between the intermediate electrode 3 and the other end of the strip-shaped lead conductor 20. Temperature fuse element 6, temperature fuse element 5
Is the flux applied to the Reference numeral 12 denotes a resin cover film as a sealing material, which has a current fuse element container and a temperature fuse element container.
The current fuse element and the flux application temperature fuse element are individually sealed by being bonded or fused to the periphery of the insulating support plate and the center of the intermediate electrode. Instead of the individual sealing, the current fuse element and the flux application temperature fuse element can be sealed in a common container.

The temperature fuse element 5 is a low melting point fusible alloy having a solidus temperature of 50 to 200 ° C., such as a lead-tin alloy, and has a bending rigidity capable of supporting the weight of the intermediate electrode 3 as described later. Is used. As the flux 6, a flux mainly composed of rosin can be used.

The insulating support plate 11 and the resin cover film 12 are made of a thermoplastic resin film having a thickness of 0.1 to 0.25 mm, preferably, polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate. ,
An engineering plastic film such as polysulfone can be used. The vertical and horizontal dimensions of the insulating support plate and the resin cover film are usually (3.0 to 7.0) mm × (6.0 to 6.0).
15.0) mm.

The strip-shaped lead conductor 2 and the intermediate electrode 3 include:
For example, a thin plate of iron-nickel alloy, copper, copper-nickel alloy, nickel, copper-plated nickel, or the like can be used, and the two dimensions of the strip-shaped lead conductor are usually a thickness (0.07 to 0.120) m.
m × width (2.0-5.0) mm, and the dimensions of the intermediate electrode 3 are the same as those of the strip-shaped lead conductor 2 and have a width (2.0-6.0) m.
m × length (2.0 to 6.0) mm.

[0010] The adhesive includes a polyamide-based, rubber-based,
Acrylic, epoxy, polyester, phenol, vinyl acetate, etc. hot melt, adhesive or thermosetting adhesives can be used.

The current fuse element 4 includes a metal having a solidus temperature of 600 ° C. or higher, for example, a silver-copper alloy, copper,
Copper-nickel alloy, nichrome or the like can be used, and the wire diameter is usually on the order of several hundreds to several tens of μm.

In the thin composite fuse according to the present invention,
An insulating support plate such as a ceramic substrate may be used instead of the above-mentioned insulating support plate, and a sealing material such as a ceramic cover or a curable resin (for example, epoxy resin) may be used instead of the resin cover.

FIG. 2A shows an example of a lead frame L used in the present invention. In FIG. 2A, 3 is an intermediate electrode portion, and 2 and 2 are a pair of strip-shaped lead conductors sandwiching the intermediate electrode portion. Reference numeral a denotes an outer frame, and the intermediate electrode portion 3 is connected to the outer frame a by a bridge c on both sides, and each strip-shaped lead conductor 2 is connected by a bridge b at a rear end.

In order to manufacture the thin composite fuse shown in FIG. 1 according to the present invention, first, as shown in FIG.
The intermediate electrode portion 3 of the frame L and one of the strip-shaped lead conductors 2
The band-shaped temperature fuse element 5 is spot-welded to the tip of the intermediate electrode 3 by resistance welding or laser welding, and then both sides of the intermediate electrode 3 are separated from the outer frame a to reduce the weight of the intermediate electrode. With the temperature fuse element 5 supporting the insulating support plate 11, the insulating support plate 11 is fixed to the intermediate electrode portion 3 and the end portions of the strip-shaped lead conductors 2 and 2 as shown in FIG. After fixing the insulating support plate to the lead frame,
If the two sides of the intermediate electrode part are separated, it is difficult to cut the bridge at both side edges of the intermediate electrode part, and the bridge is cut at both side edges of the insulating support plate, exposing the electrodes and inevitable insulation failure. Therefore, in the present invention, the insulating support plate is fixed after separating both sides of the intermediate electrode from the outer frame.)

In supporting the intermediate electrode 3 by the temperature fuse element 5, the lead of the temperature fuse element is removed.
The maximum strain ε acting on the tip side of the conductor is w, the weight of the intermediate electrode is L, the length is L, the thickness of the belt-shaped temperature fuse element is t,
When the width is d, the length is e, the specific gravity is ρ, and the elastic modulus is E, the acting moment M is

M = w [(L / 2) + e] + (tde ² ρ / 2)

The bending rigidity EI is given by

[0018] EI = Edt ^3/12

Given by

Ε = Mt / EI = 12 [w [(L / 2) + e] + (tde ² ρ / 2)] / (Edt ³ )

Is given by Thus, the elastic modulus E of the band-shaped temperature fuse element is increased due to work hardening by rolling, and the thickness t of the band-shaped temperature fuse element is set to 0.
When the width d approaches the width of the strip-shaped lead conductor, ε can be easily suppressed to below the yield point of the temperature fuse element alloy. The electrode can be supported substantially horizontally without sagging by the temperature fuse element. The welding of the belt-shaped temperature fuse element 5 to the intermediate electrode 3 and the welding of the temperature fuse element to the tip of the strip-shaped lead conductor are spot weldings in a very short time. Since the material is hardly heat-softened except at the welding point, the elastic modulus E
And the horizontal support of the intermediate electrode by the temperature fuse element is not hindered.

After fixing the insulating support plate as described above, a current fuse element is connected between the intermediate electrode and the other end of the strip-shaped lead conductor, and flux is applied to the temperature fuse element. Then, sealing with a resin cover film is performed, and the strip-shaped lead conductor is separated from the outer frame of the lead frame, thereby completing the production of the thin composite fuse shown in FIG.

In the above, the current fuse element can be connected between the intermediate electrode and the other end of the strip-shaped lead conductor before the insulating support plate is fixed (this current fuse element is Outer diameter is several tens μm to several hundred μ
m, and it is difficult to support the intermediate electrode with a current fuse element instead of a temperature fuse element).

In the encapsulation with the resin cover film, as shown in FIG. 3, a temperature hue is applied to the lead frame.
Insulation of the intermediate product E in which a fuse element is connected, both ends of the intermediate electrode are cut off, an insulating support plate is fixed, a current fuse element is connected to the lead frame, and a flux is applied to the temperature fuse element. The support plate 11 is set on the base 7, and a long groove-shaped resin cover film 1 is formed on the insulating support plate 11 in a direction orthogonal to the longitudinal direction of the strip-shaped lead conductor.
20 (long resin cover film 120 and insulating support plate 11)
(Equal width) is extended and placed (spaced in FIG. 3 for convenience of illustration), and the position of the long resin cover film 120 is adjusted by an alignment jig (not shown). The heating mold 8 having the concave portions n and m for accommodating the current fuse element and the flux application temperature fuse element is lowered, and the long insulating support plate 120 is heated to the insulating support plate 11. A Thomson blade is provided on the heating mold 8 so as to cut the resin cover film 120 at both end edges of the width of the insulating support plate 11, and the resin cover film 12 is formed at the same time as the above-mentioned heat fusion.
0 or a cutter separate from the heating mold 8
Thus, the resin cover film 120 can be cut after the thermal fusion.

In the above, the long resin cover film 1
20 is extended into the space above the insulating support plate 11, and both ends thereof are supported by a clamp or the like with a constant low gripping force, and the heating mold is lowered against the low gripping force of the long resin cover film. The lowering may be performed under tension (a low tension that does not substantially cause elongation of the long resin cover film).

Also, ultrasonic welding is performed by using an ultrasonic welding tool horn having concave portions for accommodating the flux application temperature fuse element and the current fuse element, respectively, in place of the heating mold. Can also.

Also, a plurality of the above-mentioned intermediate products are arranged in parallel, a long groove-shaped molded resin cover film is arranged thereon, and the intermediate products are arranged in parallel using the long resin cover film. All at once, connecting the temperature fuse element to the lead frame, disconnecting both ends of the intermediate electrode, connecting the current fuse element to the lead frame, and connecting the temperature fuse element to the lead frame. A plurality of intermediate products coated with flux are placed between the long resin cover film and the long insulating support plate, and each intermediate product is sealed with the insulating support plate and the resin cover film, and Can be cut to obtain the final product.

Since the thin composite fuse manufactured according to the present invention is thin, it can be set compactly in a battery pack, and when the lithium ion secondary battery is over-discharged, the current fuse element is heated by its Joule heat. The battery is cut off from the load by fusing operation, and the battery is cut off from the load by fusing the temperature fuse element due to abnormal heat generation of the battery without overcurrent. -The fuse element is blown by its own heat generated by the joule, and the current fuse element is not blown at a current larger than the rated current of less than twice the rated current without blowing the current fuse element. Temperature hue by generated heat
Therefore, it is possible to prevent the occurrence of an accident, for example, by blowing off the battery element to cut off the battery from the load.

[0029]

According to the present invention, a thin composite fuse for shutting off a battery from a load during abnormal discharge or abnormal heating of a lithium ion secondary battery can be manufactured using a lead frame. It is extremely useful for high-efficiency and high-speed production of

[Brief description of the drawings]

FIG. 1 is a view showing a thin composite fuse according to the present invention.

FIG. 2 is a view showing a main part of a method for manufacturing a thin composite fuse according to the present invention.

FIG. 3 is a view showing an example of a sealing method in a method of manufacturing a thin composite fuse according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Insulation support plate 12 Resin cover film 2 Strip lead conductor 3 Intermediate electrode 4 Current fuse element 5 Temperature fuse element L Lead frame

Claims (2)

[Claims] An intermediate electrode and a pair of strip-shaped lead conductors sandwiching the intermediate electrode are fixed on an insulating support plate, and a temperature probe is provided between the intermediate electrode and one of the strip-shaped lead conductor tips. A composite fuse in which a current fuse element is connected between the intermediate electrode and the other end of the strip-shaped lead conductor, and the insulating support plate is sealed with a sealing material; A thin composite fuse characterized by imparting flexural rigidity to a temperature fuse element capable of supporting an intermediate electrode at one end of a strip-shaped lead conductor with respect to its own weight. 2. An intermediate electrode and a pair of strip-shaped lead conductors sandwiching the intermediate electrode are fixed on an insulating support plate, and a temperature probe is provided between the intermediate electrode and one of the strip-shaped lead conductor tips. A method of manufacturing a composite fuse in which a current fuse element is connected between an intermediate electrode and the other end of a strip-shaped lead conductor, and an insulating support plate is sealed with a sealing material. A lead frame in which the rear ends of the pair of strip-shaped lead conductors and both sides of the intermediate electrode are connected to the outer frame is used, and the intermediate electrode and one end of the strip-shaped lead conductor are connected to each other. The thin composite fuse is characterized in that the two members are connected to each other by a temperature fuse element, then both sides of the intermediate electrode are separated from the outer frame, and then the insulating support plate is fixed over the intermediate electrode and the end portions of both band-shaped lead conductors. Manufacturing method.