JP2001195970A - Fuse and cell using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an over current flows into a breaking path by short circuit of a wiring pattern to cut off the breaking path, nevertheless generating a large reverse electromotive force by the coils arranged in an electric equipment so as to adversely affect the IC parts or the like of the electric equipment of prior art. SOLUTION: This fuse comprises a breaking path 13 connecting a pair of electrodes 12 to cut off an electric current path, and a resistor 14 connected parallel to the pair of electrodes 12. When the fuse H is used in an electric equipment, an over current flows into the breaking path by short circuit of a wiring pattern to break off the breaking path, but generating a large back electromotive force due to the coils arranged in an electric equipment. However, the back electromotive force is suppressed by the resistor 14 to prevent the IC parts or the like from being damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuse used for electric equipment and the like, and a battery using the fuse.

[0002]

2. Description of the Related Art In a conventional fuse, a power supply circuit portion of an electric device is generally provided on a printed circuit board. A silver paste is printed between wiring patterns near the power supply circuit portion. When the air flows, an interruption path for interrupting the electric circuit is formed. Further, the battery has a configuration in which an insulating substrate provided with a conductive path made of silver or the like is attached to the battery cover, and when the pressure in the cover increases, the cover is displaced to break the insulating substrate, The conductive path is cut off, thereby preventing the battery from exploding.

[0003]

However, in the conventional fuse, a short circuit in a wiring pattern or the like causes a current of a predetermined value or more to flow in the interrupting path, and the interrupting path is interrupted. There is a problem that a large back electromotive force is generated by the coil and the like, and the back electromotive force affects the IC parts and the like of the electric equipment, and the IC parts and the like are damaged.

In a conventional battery, when the pressure inside the cover increases due to charging or the like, the displacement of the cover breaks the insulating substrate and cuts off the conductive path to prevent the battery from exploding. However, in an electric device using this battery, even if a short circuit occurs in the wiring pattern or the like, the conductive path is not interrupted. Therefore, there is a problem that the IC parts and the like are damaged. In addition, since the capacity remains even after the fuse is blown, it may be dangerous if left unattended depending on the internal state.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuse having no damage to an IC component or the like of an electric device, and a battery having a simple configuration and a fuse.

[0006]

As a first means for solving the above-mentioned problems, an insulating substrate made of an insulating material is provided.
At least a pair of electrodes formed on the insulating substrate,
An interrupting circuit connected between the pair of electrodes and interrupting an electric circuit when a current equal to or greater than a predetermined value flows, and a resistor connected in parallel with the interrupting circuit between the pair of electrodes.

[0007] As a second solution, the cut-off path is provided with a narrow portion which is partially narrow.
As a third solution, the cut-off path is provided with a V-shaped inclined portion at a side edge thereof to form the narrow portion. Further, as a fourth solution, the cut-off path is provided with an uneven portion on a side edge thereof to form the narrow portion.

As a fifth solution, a protective film made of an insulating material is formed on the cutoff path.
As a sixth solution, the protection film made of an insulating material is formed on the resistor. As a seventh solution, the resistor is formed of a material having a positive temperature coefficient.

According to an eighth aspect of the present invention, there is provided a fuse having the configuration according to any one of claims 1 to 6, and a cover member accommodating a power generating element and having the fuse attached thereto.
The cover member is provided with pressure-sensitive means that is displaced in accordance with an increase in the internal pressure of the cover member, and one of the electrodes of the fuse attached to the cover member has a positive electrode or a negative electrode of the power generating element. The insulating substrate is broken by the displacement of the pressure-sensitive means due to an increase in the internal pressure of the cover member, and the electric circuit of both the cutoff path and the resistor is cut off.

[0010] As a ninth solution means, the insulating substrate is provided with a stress concentration portion. In addition, the tenth
As a means for solving the problem, a notch is provided on a side portion of the insulating substrate to form the stress concentration portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a fuse of the present invention is shown in FIGS.
Referring to FIG. 3, FIG. 1 is a perspective view showing a first embodiment of the fuse of the present invention, FIG. 2 is a perspective view showing a second embodiment of the fuse of the present invention, and FIG. Third
It is a perspective view showing an example.

First, a first embodiment of a fuse according to the present invention will be described with reference to FIG. 1. An insulating substrate 11 made of an insulating material such as ceramic is formed in a rectangular chip shape, and has both longitudinal side portions 11a. Are provided with notches 11b facing each other at the center of the notch. The insulating substrate 1
On one surface, a pair of electrodes 12 are formed at intervals, and the electrodes 12 are formed by, for example, a silver film formed on the insulating substrate 11 and a solder provided on the silver film. I have.

The cutoff path 13 is made of a coating of silver or the like, and is formed on the insulating substrate 11 while being connected between the pair of electrodes 12. The cut-off path 13 is provided with a V-shaped inclined portion at both side edges 13a to form a narrow portion 13b having a narrow width. When a current equal to or more than a predetermined value flows between the narrow portions 13b
Is cut and the electric circuit is cut off. Further, the cut-off path 13 obtains a desired cut-off current value by changing the film thickness and the width of the narrow portion 13b. The cutoff path 13 may be formed of the same material as the silver coating of the electrode 12 in the same step.
The inclined portion a may be provided on only one side.

The resistor 14 is made of a coating of a material having a positive temperature coefficient, such as cermet, carbon, or metal oxide, and is connected between the pair of electrodes 12 in parallel with the cutoff path 12. 11 is formed. The resistor 14 and the cutoff path 13 are formed by firing simultaneously. The protective film 15 is made of an insulating material. The protective film 15 is formed on the insulating substrate 11 so as to cover the cutoff path 13 and the resistor 14. Note that the protection film 15 may cover only the cutoff path 13.

The fuse H thus configured is used by being incorporated into an electric device. When the fuse H is used in an electric device, a short circuit of a wiring pattern or the like causes the cutoff path 13 to exceed a predetermined value. Current flows and the cutoff path 1
3 is cut off. At this time, even if a large back electromotive force is generated by a coil or the like used in the electric device, the resistor 1
4, the back electromotive force is suppressed, and the IC parts and the like of the electric equipment are not damaged. Further, when the fuse H in which the resistor 14 is formed of a material having a positive temperature coefficient is used for a battery, when the cutoff path 13 is cut off, when the battery temperature is relatively low, the resistance value of the resistor 14 itself is low. As a result, the discharge current of the battery increases, but when the temperature of the battery is high, the resistance value of the resistor 14 itself increases, and the discharge current of the battery decreases, so that the temperature rise of the battery itself is suppressed. Therefore, particularly when the temperature of the battery itself is high, the discharge current is reduced to suppress an increase in pressure inside the battery.

FIG. 2 shows a fuse according to a second embodiment of the present invention. The second embodiment differs from the first embodiment in the configuration of the narrow portion 13b. A concave portion is provided in the edge portion 13a, and a narrow portion 13 partially narrowed is provided.
b is formed. Other configurations are the same as those of the above-described embodiment, and therefore, the same components are denoted by the same reference numerals, and description thereof is omitted here. Note that a concave portion may be provided only on one side of the side edge portion 13a.

FIG. 3 shows a third embodiment of the fuse of the present invention. The third embodiment differs from the first and second embodiments in the configuration of the narrow portion 13b. In this embodiment, a narrow portion 13b is formed in which both sides 13a are provided with an uneven portion and a part of the narrow portion 13b becomes narrow. Other configurations are the same as those of the above-described embodiment, and therefore, the same components are denoted by the same reference numerals, and description thereof is omitted here. The side edge 13a
May be provided only on one side.

Next, the battery of the present invention using the fuse according to the present invention will be described with reference to FIGS. 4 to 7. FIG. 4 is an exploded perspective view of a main part of the battery of the present invention, and FIG. FIG. 6 and FIG. 7 are sectional views of the main part of the battery, and FIG. 6 and FIG.

Next, the configuration of the battery according to the present invention will be described with reference to FIGS. 4 to 7. As shown in FIG. A battery lid (negative case) 4, which has an insulator 3, a diaphragm portion D forming pressure sensing means, and a safety valve portion Z and constitutes a part of a cover member K, a holder 5, an external electrode 6, It mainly comprises a fuse H and a rivet 8. As shown in FIG. 5, the circuit breaker T for a battery having such a configuration is as follows.
A flange 4j around the battery cover 4 is attached to the cover member K by welding or the like, so that the inside of the cover member K is airtightly shielded.

The terminal portion 2 is made of aluminum and is bent at a substantially right angle as shown in FIG. 4. A connecting piece portion 2a to be welded to the connecting portion 8d of the rivet 8 extends at one end in the longitudinal direction. Have been. A plurality of substantially circular openings 2c are formed in the flat portion 2b.

The insulator 3 is made of a resin material such as PP, and has a cylindrical portion 3a through which a rivet 8 is inserted near one end, and a battery cover 4
3b that allows the diaphragm portion D to swell downward in the figure, vent holes 3c and 3c formed through the bottom surface of the concave portion 3b, holes 3d for welding, and a safety valve portion Z of the battery lid 4. Are formed with substantially rectangular openings 3e and 3e communicating with the projections, and positioning projections 3f. The battery lid 4 is made of a conductive metal plate such as a stainless steel material, and is formed in a substantially rectangular lunch box shape with a substantially rectangular outer shape as shown in FIG. Is formed so as to project downward by drawing or the like to form a flat bottom plate 4a.

A ridge 4b is formed around the bottom plate 4a to connect the flange 4j and the bottom plate 4a. Near one end of the bottom plate 4a, a cylindrical portion 3a through which a rivet 8 is inserted.
Is formed. A diaphragm portion D as pressure sensing means is formed on the right side of the hole 4c in the drawing, and the diaphragm portion D is formed with a concave portion 4k in which a part of the back surface of the bottom plate 4a is formed by annularly recessing the outer peripheral portion. The connecting portion 4d is formed by making the bottom surface of the concave portion 4k thin. In the vicinity of the central portion of the connecting portion 4d, a convex portion 4e protruding toward the fuse H above in the figure is formed.

The diagram portion D, which is a pressure-sensitive means, has a connecting portion 4d bulging downwardly in a bowl shape in the direction in which the central convex portion is moved away from the upper fuse H. FIG.
The bottom plate 4a near the other end of the battery cover 4 shown in FIG.
The safety valve portion Z is formed on a part of the bottom plate 4a, a protrusion 4f having an annular outer shape and protruding upward in the drawing, and a battery cover 4 and a protrusion 4f formed at the root of the protrusion 4f.
The connecting portion 4g is formed thinner than the protruding portion 4f, and the shape of the connecting portion 4g as viewed from above is formed in an annular shape.

In such a safety valve portion Z, the projecting direction of the projecting portion 4f projects to the outside of the battery cover 4 for hermetically shielding the inside of the battery. When the battery pressure rises and the internal pressure of the battery rises above a predetermined position, the thin connecting portion 4g is broken. The high-pressure gas inside the battery is discharged to the outside from the broken portion of the connecting portion 4g, thereby preventing the battery from exploding in advance. Also, the bottom plate 4 is connected to the other end of the battery cover 4.
Formed at the corner of a is a projection 4h for positioning, which is formed by projecting a part of the ridge 4b inward, and a flange 4j extending outward on the outer peripheral side of the upper end of the ridge 4b. Formed battery lid 4
Is configured.

The holder 5 is formed of a resin material such as PPS, and has a size to be fitted into the ridge 4b of the battery cover 4 as shown in FIG. Near one end of the holder 5, a through hole 5a penetrating the cylindrical portion 3a through which the rivet 8 is inserted, and a periphery of the through hole 5a is provided in a concave portion.
A rivet connection portion 9a formed for connecting the rivet 8, and an opening 5 extending a pair of first and second leads 9b and 9c for supporting the fuse H, respectively.
b, 5b, a pedestal portion 5c holding the external electrode 6, an electrode connecting portion 9d connected to the connecting portion 6c of the external electrode 6, a fixing portion 9e welded to the battery lid 4, and a safety valve portion Z. An opening 5d formed at the position thus set and a notch 5e into which a positioning projection 4h of the battery lid 4 is fitted are provided.

The holder 5 has a rivet connection portion 9a, first and second leads 9b and 9c, an electrode connection portion 9d,
The fixing portion 9e and the like are integrated by insert molding or the like. The holder 5 has a hole 5f for exposing the lower surface of the electrode connection portion 9d. The hole 5f is passed through the welding tool to the electrode connection portion 9d of the holder 5, and the welding tool is connected to the external electrode 6 from above. The external electrode 6 is fixed to the holder 5 and electrically connected to the second lead 9c by performing spot welding by sandwiching the external electrode 6 against the connecting portion 6c.

The rivet connection portion 9a and the first lead 9b
The fuse H has a configuration as shown in the first to third embodiments (FIGS. 1 to 3), and a pair of electrodes 12 has first and second leads, respectively. 9b, 9c
Are connected, and the rivet 8 and the external electrode 6 are electrically connected. On the other hand, the fixing portion 9e is independent and is not electrically connected to the other. The fixing portion 9e of the holder 5 is attached to the bottom plate 4a of the battery cover 4 by spot welding or the like.

The external electrode 6 is formed by plating a metal plate such as an iron plate with nickel, and has an electrode portion 6a having a substantially rectangular outer shape, and leg portions 6 bent downward from both side edges of the electrode portion 6a.
b, 6b, and a connection portion 6c connected to the electrode connection portion 9e of the holder 5 are provided. And the external electrode 6
When the circuit breaker T for the battery is incorporated into the cover member K, it becomes the positive electrode of the battery, and one electrode 12 of the fuse H is connected to this positive electrode via the second lead 9c. The fuse H provided on the diaphragm D
As described above, electrodes are provided on the insulating substrate 11 made of a brittle insulating material such as ceramics, the electrodes 12, the cutoff paths 13 and the resistors 14 provided between the electrodes 12, and provided on the insulating substrate 11. It is formed of a notch 11b forming a portion, and a protection film 15 provided on the cutoff path 13 and the resistor 14 (not shown).

The fuse H has wide electrodes 12 at both ends.
However, as shown in FIG. 5, the first and second leads 9 of the holder 5
b, 9c, the first and second leads 9b, 9
c and the electrode 12 are connected by solder. Further, an electric circuit including the blocking path 13 and the resistor 14 which are in parallel with each other is formed between the first and second leads 9b and 9c.

The rivet 8 is made of aluminum, and as shown in FIG. 4, a cylindrical portion 8a having a slightly thinner tip end, a flange portion 8b provided at the lower end, and an upper portion extending along the outer periphery of the flange portion 8b. An annular ridge 8c protrudes and a connecting portion 8d protruding laterally from the flange 8b. The connecting piece 8a of the terminal portion 2 is welded to the connecting portion 8d. Has become. The insulator 3, the battery cover 4, and the holder 5 are integrated by caulking the tip of the cylindrical portion 8a of the rivet 8, and this caulked portion is connected to the rivet connection portion 9a of the holder 5. Therefore, the external electrode 6 is electrically connected to the terminal portion 2 through the electric circuit such as the cutoff path 13 of the fuse H and the resistor 14.

The battery of the present invention as described above is used for a battery (not shown), for example, a lithium ion secondary battery or the like. A cover member opened as shown in FIGS. An electric circuit blocking component T is inserted from above K, and the flange 4j of the battery cover 4 is connected by welding or the like over the entire periphery of the fitting portion of the cover member K, and the electrolytic solution provided on the side surface of the cover member K After injecting the electrolyte from the injection hole (not shown),
By closing the injection hole by welding or the like, the inside of the cover member K is sealed.

When a battery using such a fuse H is used in an electric device, if a current of a predetermined value or more flows during use, the cutoff path 13 of the fuse H is cut off. Then, even if a large back electromotive force is generated by a coil or the like used in the electric device, the back electromotive force is suppressed by the resistor 14, so that the IC parts of the electric device are not damaged.

When a fuse H formed of a material having a positive temperature coefficient is used for the resistor 14, when the cutoff path 13 is cut off, and when the battery temperature is relatively low, the resistance of the resistor 14 itself increases. And the discharge current of the battery increases,
When the temperature of the battery is high, the resistance value of the resistor 14 itself increases and the discharge current of the battery decreases, so that the rise in the temperature of the battery itself is suppressed. When the pressure is high, the discharge current is reduced to suppress an increase in pressure inside the battery.

The path of the current when charging the battery of the present invention is sequentially from the external electrode (positive electrode) 6 to the second lead 9.
c, the fuse H, the first lead 9b, the rivet 8, and the terminal portion 2, and are led out to a power generating element (not shown) inside the battery. Further, if such a battery is overcharged or charged with a current larger than a specified current, an abnormality occurs inside the battery, and the pressure and temperature inside the battery rise abnormally.

Then, the increased internal pressure inside the battery is transmitted to the electric circuit interrupting component T of the battery, and the increased internal pressure of the battery is transmitted to the diaphragm portion D through the ventilation holes 3c, 3c of the insulator 3.
To the safety valve portion Z via the openings 3e and 3e. Then, when the internal pressure of the battery reaches a predetermined pressure, the connecting portion 4d, which is a thin-walled diaphragm portion, which is a pressure-sensitive means, is flipped upward at a stretch as shown in FIG. 7 from the state of FIG.

By the sudden reversal of the connecting portion 4d, the convex portion 4e of the diaphragm portion D collides with the lower surface of the notch portion 11b which is the stress concentration portion of the insulating substrate 11 of the fuse H located above, and the insulating substrate 11 From the notch 11b. The breaking of the insulating substrate 11 cuts off the electric circuit between the cutoff path 13 and the resistor 14, and the first and second leads 9
The electric path between b and 9c is cut off, and the electric path between the external electrode 6 and a power generating element (not shown) in the battery is cut off, so that charging of the battery is stopped. As a result, a rise in the pressure inside the battery can be suppressed, and a failure such as a rupture of the battery can be prevented.

If the internal pressure of the battery further increases due to the effect of the electrolyte inside the battery even if the fuse H is broken and the electric circuit is cut off, the safety valve portion Z of the battery lid 4 will be described.
The thin connection portion 4g is broken, and the high-pressure gas in the battery can be discharged from the broken portion to the outside of the battery through the opening 5d. Has double safety measures. Then, for example, the operating pressure of the electric circuit interrupting component T of the battery is such that the diaphragm 4d is turned over at once in the range of 4 to 10 atm, and
The connection portion 4g of the safety valve portion Z is set to be broken in the range of 0 to 20 atmospheres.

[0038]

The fuse according to the present invention comprises an insulating substrate 11 made of an insulating material, at least a pair of electrodes 12 formed on the insulating substrate 11, and a connection between the pair of electrodes 12 and a predetermined value or more. An interruption path 13 that interrupts an electric circuit when a current flows, and the interruption path 1 between the pair of electrodes 12.
3 and the resistor 14 connected in parallel, when this fuse H is used in an electric device, a current of a predetermined value or more flows through the cutoff path 13 due to a short circuit of a wiring pattern or the like. However, at this time, even if a large back electromotive force is generated by a coil or the like used in the electric device, the back electromotive force is suppressed by the resistor 14 and the IC parts of the electric device are damaged. A fuse that does not have any problem can be provided.

Further, the cut-off path 13 is provided with a narrow portion 13b which is partially narrow, so that by changing the film thickness of the narrow portion 13b and the width of the narrow portion 13b, a desired cut-off can be achieved. A current value is obtained, and a highly accurate fuse can be provided.
Further, the cut-off path is provided with a V-shaped inclined portion at the side edge portion 13a to form the narrow width portion 13b, so that the configuration is simple, and the film thickness of the narrow width portion 13b and the narrow width portion 13b are reduced. By changing the width, a desired breaking current value can be obtained, and a highly accurate fuse can be provided. Also, in the shutoff path 13,
Since the narrow portion 13b is formed by providing an uneven portion on the side edge portion 13a, the structure is simple, and by changing the film thickness of the narrow portion 13b and the width of the narrow portion 13b, a desired breaking current can be obtained. As a result, a fuse with good accuracy can be provided.

Further, since the protective film 15 made of an insulating material is formed on the cutoff path 13, there is no adhesion of dust and the like on the cutoff path 13, so that a safe and reliable fuse can be provided. Also,
Since the protective film 15 made of an insulating material is formed on the resistor 14, the dust and the like do not adhere to the resistor 14, and the resistor 14 can be protected from moisture, so that a highly accurate fuse can be provided. Further, since the resistor 14 is formed of a material having a positive temperature coefficient, when the fuse H is used for a battery,
When the temperature of the battery is relatively low when the cutoff path 13 is interrupted, the resistance value of the resistor 14 itself decreases and the discharge current of the battery increases, but when the battery temperature is high, the resistance of the resistor 14 decreases.
As the resistance value of the battery itself increases, the discharge current of the battery decreases, and the rise in the temperature of the battery itself is suppressed. For this reason, particularly, when the temperature of the battery itself is high, the discharge current is reduced. The increase in pressure inside the battery can be suppressed, and safety is high.

Further, by using the fuse H for the battery, when the cutoff path 13 is cut off, even if a large back electromotive force is generated by a coil or the like, the back electromotive force is suppressed by the resistor 14 and the There is no possibility that the IC parts of the device are damaged, and the pressure-sensitive means D due to the increase in the internal pressure of the cover member K.
, The insulating substrate 11 of the fuse H is broken, and the electric circuits of both the interrupting paths 13 and 14 are interrupted.
It is possible to provide a battery capable of suppressing an increase in pressure inside the battery and preventing a failure such as a rupture of the battery. Further, even after the cutoff path 13 is cut off, current flows little by little, and the battery is completely discharged and cannot be reused.

Further, since the stress concentration portion is provided on the insulating substrate 11, the insulating substrate 11 is easily broken, and the electric circuit can be reliably cut off. In addition, since the notch portion 11b is provided in the side portion 11a of the insulating substrate 11 to form the stress concentration portion, it is possible to provide an inexpensive insulating substrate that has a simple configuration, is easy to break, and is inexpensive.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a fuse according to the present invention.

FIG. 2 is a perspective view showing a second embodiment of the fuse of the present invention.

FIG. 3 is a perspective view showing a third embodiment of the fuse of the present invention.

FIG. 4 is an exploded perspective view of a main part of the battery of the present invention.

FIG. 5 is a sectional view of a main part of the battery of the present invention.

FIG. 6 is an explanatory diagram of the operation of the battery of the present invention.

FIG. 7 is an explanatory diagram of the operation of the battery of the present invention.

[Explanation of symbols]

 T Circuit blockage part of battery of the present invention 2 Terminal part 2a Connecting piece part 2b Flat part 2c Opening part 3 Insulator 3a Cylindrical part 3b Concave part 3c Vent 3d hole 3e opening 4 Battery lid 4a Bottom plate 4b Ridge part 4c Hole D Diaphragm part 4d connecting part 4e convex part Z safety valve part 4f projecting part 4g connecting part 4h projecting part 4j flange part 4k concave part 5 holder 5a through hole 5b opening part 5c pedestal part 5d opening 5e notch part 5f Part 5g Side surface 6 External electrode 6a Electrode part 6b Leg 6c Connection part 8 Rivet 8a Column part 8b Flange part 8c Annular ridge 8d Connection part 9 Lead 9a Rivet connection part 9b First lead 9c Second lead 9d Electrode connection part 9e Fixing portion H Fuse 11 Insulating substrate 11a Side portion 11b Notch portion as stress concentration portion 12 Electrode 13 Interruption path 13a Side edge portion 3b narrow section 14 resistor 15 protective film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01H 85/00 N 85/36 Z

Claims (10)

[Claims] 1. An insulating substrate made of an insulating material, at least a pair of electrodes formed on the insulating substrate, and a cut-off path connected between the pair of electrodes and cutting off an electric circuit when a current of a predetermined value or more flows. And a resistor between the pair of electrodes and a resistor connected in parallel with the cutoff path. 2. The fuse according to claim 1, wherein the cut-off path is provided with a narrow portion that is partially narrow. 3. The fuse according to claim 2, wherein the cut-off path is provided with a V-shaped inclined portion at a side edge thereof to form the narrow portion. 4. The fuse according to claim 2, wherein the cut-off path is provided with a concavo-convex portion on a side edge thereof to form the narrow portion. 5. The fuse according to claim 1, wherein a protective film made of an insulating material is formed on the cutoff path. 6. The fuse according to claim 5, wherein the protective film made of an insulating material is formed on the resistor. 7. The fuse according to claim 1, wherein the resistor is formed of a material having a positive temperature coefficient. 8. A fuse having the configuration according to claim 1 and a cover member accommodating a power generating element and having the fuse attached thereto, wherein the cover member is provided with an internal pressure of the cover member to increase. A positive electrode or a negative electrode of the power generating element is connected to one of the electrodes of the fuse attached to the cover member, and the pressure sensitive means is increased by an increase in the internal pressure of the cover member. The battery is characterized in that the insulating substrate is broken by the displacement of, and the electric circuit of both the cutoff path and the resistor is cut off. 9. The battery according to claim 8, wherein a stress concentration portion is provided on the insulating substrate. 10. The battery according to claim 9, wherein a cutout portion is provided on a side portion of the insulating substrate to form the stress concentration portion.