JP4738953B2 - Resistive fuse - Google Patents

Description

  The present invention relates to a fuse with resistance.

Resistive fuses are known as protective elements for electrical and electronic equipment.
The operating mechanism of this fuse with resistance is to detect the abnormality of the electronic / electrical equipment with an IC circuit and to heat the resistance by energizing, and to cut off the power supply to the electronic / electrical equipment by fusing the fuse element with the generated heat. is there.
This fuse with resistance is used in various fields. For example, it is incorporated in a battery pack of a lithium ion secondary battery together with an IC control circuit to stop charging and discharging when the secondary battery is overcharged or overdischarged. in use.

FIG. 6 shows an example of a conventional fuse with resistance, which is a substrate type using an insulating substrate 1 ′ such as a ceramic plate, and has a lead conductor connecting film electrode 12 ′ and a fuse element bonding film electrode 13 ′. Membrane resistor 11 'and lead conductor connecting membrane electrodes 14a' and 14b 'sandwiching fuse element bonding membrane electrode 13' are provided on one side of insulating substrate 1 'for connecting lead conductor on membrane resistor 11' side. The lead conductor 22 'is connected to the membrane electrode 12', the other lead conductors 23a ', 23b' are connected to the lead conductor connecting membrane electrodes 14a ', 14b' on both sides, and these lead conductor membrane electrodes 14a ', 14b 'and the fuse element bonding membrane electrode 13' are joined across the fuse element 3 ', the flux 4' is applied to the fuse element 3 ', and the one surface of the insulating substrate 1' is coated with a resin coating 5 such as an epoxy resin. It is sealed with '. (For example, see Patent Documents 1 and 2)
JP 2004-227797 A JP 2004-296422 A

FIG. 7 is a circuit diagram of a battery pack incorporating the above-mentioned resistor fuse, where E is a secondary battery, A is a resistor fuse, and B is an IC control circuit. FIG. 7 shows the state during charging, and S is a charger.
In FIG. 7, when overcharge occurs, the Zener diode D is turned on by this overcharge, the transistor Tr is turned on, a current flows through the resistor 11 ′, and the fuse element 3 ′ is blown by the energization heat of the resistor 11 ′. The secondary battery E is disconnected from the charger S and the resistor 11 ′ is disconnected from the charger S and the secondary battery E. By this separation, the heat generation of the resistor 11 ′ is stopped.

In the process from energizing heat generation of the resistance of the fuse with resistance to fusing of the fuse element, since the insulating substrate has a heat capacity, the fusing of the fuse element is delayed as the volume of the insulating substrate increases.
In the conventional fuse with resistance, as shown in Patent Documents 1 and 2, a lead conductor connecting film electrode is provided on the insulating substrate with respect to the fuse element, and the fuse element is joined across these electrodes. A lead conductor is connected to each of these film electrodes, and it is necessary to increase the planar dimension of the insulating substrate for these film electrodes, resulting in a delay in fusing of the fuse element.

  The object of the present invention is to reduce the heat capacity by reducing the planar dimension of an insulating substrate by reducing the planar size of the insulating substrate in a board-type resistor-type fuse in which a film resistor and a fuse element are provided on an insulating substrate, thereby increasing the current heating rate of the resistor. The purpose is to speed up the fusing of the fuse element.

The fuse with resistance according to claim 1 is provided with a film element and a film electrode for connecting a lead element with a film resistance and a predetermined film resistance distance provided on one surface of an insulating substrate chip, and the lead conductor is the above-mentioned lead conductor. Connected to the lead conductor connecting membrane electrode, the fuse element has one end protruding from the insulating substrate chip, the other end joined to the fuse element joining membrane electrode, and a lead different from the lead conductor The one end of the fuse element is directly joined to the tip of the conductor.
The fuse with resistance according to claim 2 is provided with a film element and a film electrode for connecting a lead element with a film resistance and a predetermined film resistance distance provided on one surface of an insulating substrate chip, and the lead conductor is the above-mentioned Connected to the lead conductor connecting membrane electrode, the middle of the fuse element is joined to the fuse element joining membrane electrode, and both ends of the fuse element protrude from the insulating substrate chip, and the leads are respectively connected to both ends of the fuse element. A lead conductor different from the conductor is directly joined.
According to a third aspect of the present invention, there is provided the fuse with resistance according to the first aspect, wherein the fuse element is a different member on both sides of the fuse element bonding film electrode.
According to a fourth aspect of the present invention, there is provided a fuse with resistance, wherein a surface resistance of the insulating substrate chip is provided with a film resistance for the fuse element and a surface film electrode for connecting the lead conductor with a predetermined film resistance distance therebetween. A fuse element bonding back film electrode connected to the fuse element bonding surface film electrode by a through hole on the back surface side of the substrate chip, and a lead conductor bonding back surface conductive to the lead conductor connection surface film electrode by a through hole. And a lead conductor connected to the back membrane electrode for connecting the lead conductor, and a fuse element is joined to the tip of a lead conductor different from the lead conductor, and a predetermined distance from the joint location The separated fuse element portions are joined to the above-mentioned back electrode for joining the fuse element.
According to a fifth aspect of the present invention, there is provided a fuse with resistance, wherein a surface resistance of the insulating substrate chip is provided with a film resistance for the fuse element and a surface film electrode for connecting the lead conductor with a predetermined film resistance distance therebetween. A fuse element bonding back film electrode connected to the fuse element bonding surface film electrode by a through hole on the back surface side of the substrate chip, and a lead conductor bonding back surface conductive to the lead conductor connection surface film electrode by a through hole. And a lead conductor is joined to the back conductor electrode for connecting the lead conductor, and the middle of the fuse element is joined to the back membrane electrode for joining the fuse element, and the lead is connected to each of both ends of the fuse element. A lead conductor different from the conductor is connected.
The fuse with resistance according to claim 6 is the fuse with resistance according to claim 5, characterized in that the fuse element is a different member on both sides of the fuse element bonding film electrode.
The resistance fuse according to claim 7 is the resistance fuse according to any one of claims 1 to 6, wherein a leading end portion of a lead conductor joined to an end portion of the fuse element is bent substantially perpendicularly to the fuse element. The portion is joined to the end of the fuse element.
The fuse with resistance according to claim 8 is sealed with a resin mold or a case so as to enclose the joint portion of the insulating substrate chip and the fuse element with the lead conductor in the fuse with resistance according to any one of claims 1 to 7. It is characterized by.

(1) The lead conductor is directly joined to the fuse element, the lead conductor connecting electrode is provided on the insulating substrate, the end of the fuse element is joined to the electrode, and the lead conductor is joined to the electrode. In contrast, since the lead conductor connecting electrode is not provided, the planar dimension of the insulating substrate can be reduced by that amount, and the heat capacity of the insulating substrate can be reduced. Therefore, it is possible to speed up the fusing of the fuse element by increasing the energization heat generation rate of the membrane resistance, and to increase the operation speed.
(2) The size of the resin package or the casing can be reduced according to the reduction of the planar size of the insulating substrate, and the resistance fuse can be downsized.
(3) Impedance for normal energization through the fuse element and the lead conductor can be reduced due to the reduction of the contact resistance interface, and the capacitance of the fuse with resistance can be increased.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A is an explanatory top view showing an embodiment of a fuse with resistance according to the present invention, and FIG. 1B is a cross-sectional view of FIG.
In FIG. 1, reference numeral 1 denotes an insulating substrate chip, which is electrically connected to a film resistor 11 and a fuse element bonding film electrode 12 superimposed on one end side of the film resistor 11 and the other end side of the film resistor 11 on the surface. And a lead conductor connecting membrane electrode 13 which are overlapped and connected to each other. The distance between the electrodes 12 and 13 is set as a predetermined film resistance distance so as to set a predetermined resistance value.
The insulating substrate chip 1 can be made of a highly heat conductive inorganic material such as ceramics or glass. The film resistor 11 can be provided by printing / baking a resistance paste such as ruthenium oxide paste, and the film electrodes 12 and 13 can be provided by printing / baking a conductive paste such as silver paste.
Reference numeral 22 denotes a lead conductor, for example, a copper conductor, which is connected to the lead conductor connecting membrane electrode 12 by welding or soldering. A flat conductor can be used for the lead conductor 22.
Reference numeral 3 denotes a fuse element, which is joined to the fuse element joining film electrode 23 in the middle by welding or the like. As the fuse element 3, it is desirable to use a composition having high bending rigidity, and a flattened one can be used.
Reference numerals 23a and 23b are lead conductors, for example, flat conductors joined to both ends of the fuse element 3 by welding or the like. When the fuse with resistance is operated, the melted fuse element is ± 90 ° with respect to the axial direction of the fuse element. In order to increase the wetted area by wetting and spreading in both directions, the tip end portion of the lead conductor is bent at a right angle, and the end portion of the fuse element is joined to the bent portion. Flat conductors can also be used for these lead conductors 23a and 23b.
Reference numeral 4 denotes a flux applied to the fuse element 3, and a flux mainly composed of rosin can be used. The melting point of the flux 4 is lower than the melting point of the fuse element 3, and the flux can be applied by heating and melting the flux, and applying and solidifying the molten flux.
Reference numeral 5 denotes a resin package, which can be provided by dropping and curing a curable resin paint such as an epoxy resin. It is desirable to reduce the size of the package by minimizing the size of the package so that the junction between the insulating substrate chip and the fuse element and the lead conductor can be included.
Instead of this resin package, a case package such as a ceramic case can also be used.

FIG. 2 is an explanatory top view showing another embodiment of the resistor-equipped fuse according to the present invention, in which a lead conductor 23a only on one end side of the fuse element 3 is joined to the embodiment shown in FIG.
In FIG. 2, reference numeral 1 denotes an insulating substrate chip, which is electrically connected to the other end side of the film resistor 11 on the surface thereof and the film resistor 11 and the fuse element bonding film electrode 13 that is connected to the one end side of the film resistor 11 in an overlapping manner. And a lead conductor connecting membrane electrode 12 which are superposedly connected to each other. The distance between these electrodes 12 and 13 is set to a predetermined film resistance distance so as to set a predetermined resistance value.
Reference numeral 22 denotes a lead conductor, for example, a copper conductor, which is connected to the lead conductor connecting membrane electrode 12 by welding or soldering. A flat conductor can be used for the lead conductor 22.
A fuse element 3 has one end joined to the fuse element joining membrane electrode 13 by welding or the like. The fuse element 3 can be flattened.
23a is a lead conductor joined to the other end of the fuse element 3 by welding or the like, for example, a flat conductor, and when the fuse with resistance is operated, the melted fuse element is moved in both directions of ± 90 ° with respect to the axial direction of the fuse element. In order to widen the wetted area by spreading out, the tip end portion of the lead conductor is bent at a right angle, and the end portion of the fuse element is joined to the bent portion. Flat conductors can also be used for these lead conductors.
Reference numeral 4 denotes a flux applied to the fuse element 3, and a flux mainly composed of rosin can be used.
Reference numeral 5 denotes a resin package, which can be provided by dropping and curing a curable resin paint such as an epoxy resin. It is desirable to reduce the size of the package by minimizing the size of the package so that the junction between the insulating substrate chip and the fuse element and the lead conductor can be included.
Instead of this resin package, a case package such as a ceramic case can also be used.

FIG. 3 (a) is a top view illustrating another embodiment of the resistor-equipped fuse according to the present invention, and FIG. 3 (b) is a back view illustrating the same.
In FIG. 3, reference numeral 1 denotes an insulating substrate chip. Reference numeral 11 denotes a film resistor provided on the surface side of the insulating substrate chip 1. 12 is a surface film electrode for connecting a lead conductor provided to be superposedly connected to one end side of the film resistor 11, and 13 is a surface film electrode for connecting a fuse element provided to be superposedly connected to the other end side of the film resistor 11. The distance between the electrodes 12 and 13 is set to a predetermined film resistance distance so as to set a predetermined resistance value.
Reference numeral 130 denotes a fuse element bonding back film electrode provided on the back surface side of the insulating substrate chip 1, which is electrically connected to the fuse element bonding surface film electrode 13 through a through hole h ₁₃ .
Reference numeral 120 denotes a back conductor electrode for connecting a lead conductor provided on the back side of the insulating substrate chip 1, which is electrically connected to the surface electrode 12 for connecting a lead conductor through a through hole h ₁₂ .
Reference numeral 22 denotes a lead conductor, for example, a copper conductor, which is connected to the lead conductor connecting back membrane electrode 120 by welding or soldering. A flat conductor can be used for the lead conductor 22.
A fuse element 3 is joined to the fuse element joining back membrane electrode 130 by welding or the like in the middle. As the fuse element 3, it is desirable to use a composition having high bending rigidity, and a flattened one can be used.
Reference numerals 23a and 23b are lead conductors, for example, flat conductors joined to both ends of the fuse element 3 by welding or the like. When the fuse with resistance is operated, the melted fuse element is ± 90 ° with respect to the axial direction of the fuse element. In order to increase the wetted area by wetting and spreading in both directions, the tip end portion of the lead conductor is bent at a right angle, and the end portion of the fuse element is joined to the bent portion. Flat conductors can also be used for these lead conductors.
Reference numeral 4 denotes a flux applied to the fuse element 3, and a flux mainly composed of rosin can be used.
Reference numeral 5 denotes a resin package, which can be provided by dropping and curing a curable resin paint such as an epoxy resin. It is desirable to reduce the size of the package by minimizing the size of the package so that the junction between the insulating substrate chip and the fuse element and the lead conductor can be included.
Instead of this resin package, a case package such as a ceramic case can also be used.

  4 (a) is a top view illustrating another embodiment of the resistor-equipped fuse according to the present invention, and FIG. 4 (b) is a back view illustrating the embodiment shown in FIG. On the other hand, the lead conductor 23a only on one end side of the fuse element 3 is joined. 4, the same reference numerals as those in FIG. 3 have the same configuration.

For the fuse element 3, a lead-free composition, for example, In 70 to 90 wt%, Cu 0.1 to 2.0 wt%, and remaining Sn can be used.
The insulating substrate chip provided with the film resistance or the like can be obtained by printing the film resistance or the film electrode on the original plate and processing the through hole, and then dividing the chip by scribing.

FIG. 5 shows the usage state of the resistor fuse shown in FIG. 1 or FIG. 3, and a resistor fuse A is connected between an electronic / electric device, for example, a personal computer Z and a secondary battery E. On the other hand, the IC control circuit B is connected in parallel.
In FIG. 5, when the secondary battery E is in an overdischarged state, the voltage sensor D operates due to a voltage drop of the secondary battery E, the transistor switch S is turned on by this operation, and the resistor 11 is energized and generates heat. 3 is melted, the computer Z and the secondary battery E are disconnected from each other, and the energization heat generation of the resistor 11 is stopped.
In this case, the melting point of the fuse element part 3a on the secondary battery E side is made higher than the melting point of the fuse element part 3b on the computer Z side to delay the fusing of the fuse element part 3a on the secondary battery E side. Thus, the discharge amount of the accumulated charge of the secondary battery E can be increased as much as possible. Thus, the residual charge of the secondary battery E is sufficiently reduced, so that the battery pack can be safely disposed of.

  In the fuse with resistance shown in FIG. 1, the dimensions of the insulating substrate chip 1 are 3 mm long × 1.2 mm wide × 0.63 mm thick, and the fuse element 3 has a composition Bi—In—Sn, an outer diameter of 0.5 mmφ × length. 2.5 mm was used, the membrane resistance value between the fuse element joining membrane electrode 13 and the lead conductor connecting membrane electrode 12 was 40Ω, and the sealing was an epoxy resin package.

[Comparative Example]
In the fuse with resistance shown in FIG. 6, the size of the insulating substrate 1 ′ is 6 mm long × 6 mm wide × 0.63 mm thick, and the fuse element 3 ′ has a composition Bi-In-Sn, an outer diameter of 0.5 mmφ × length. 3.4 mm is used, the membrane resistance value between the fuse element bonding membrane electrode 13 ′ and the lead conductor connecting membrane electrode 12 ′ is 40Ω as in the embodiment, and the sealing is epoxy resin as in the embodiment. Packaged.

  For the example product and the comparative example product (n = 20), the time until the fuse element was blown by applying a current of 0.27 A was 6 to 8 seconds for the example product. It was about 30 seconds shorter.

1 is a view showing an embodiment of a fuse with resistance according to the present invention. It is drawing which shows the Example different from the above of the fuse with a resistance which concerns on this invention. It is drawing which shows the Example different from the above of the fuse with a resistance which concerns on this invention. It is drawing which shows the Example different from the above of the fuse with a resistance which concerns on this invention. It is drawing which shows the use condition of the fuse with a resistance which concerns on this invention. 2 is a view showing a conventional fuse with resistance. It is drawing which shows the use condition of the conventional fuse with a resistor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating board chip 11 Membrane resistance 12 Lead conductor connection electrode or lead conductor connection surface electrode 13 Fuse element bonding membrane electrode or fuse element bonding surface membrane electrode 120 Lead conductor connection back membrane electrode 130 Fuse element bonding back membrane Electrode h ₁₂ Through hole h ₁₃ Through hole 22 Lead conductor 23a Lead conductor 23b Lead conductor 3 Fuse element 4 Flux 5 Resin package

Claims (8)

A fuse element bonding membrane electrode and a lead conductor connecting membrane electrode are provided on one side of the insulating substrate chip with a membrane resistance and a predetermined membrane resistance distance therebetween, and the lead conductor is connected to the lead conductor connecting membrane electrode, One end portion of the fuse element protrudes from the insulating substrate chip, and the other end portion is bonded to the fuse element bonding film electrode, and the one end of the fuse element is connected to a tip end of a lead conductor different from the lead conductor. Resistive fuse characterized in that the parts are directly joined. A fuse element bonding membrane electrode and a lead conductor connecting membrane electrode are provided on one side of the insulating substrate chip with a membrane resistance and a predetermined membrane resistance distance therebetween, and the lead conductor is connected to the lead conductor connecting membrane electrode, The middle part of the fuse element is joined to the film electrode for joining the fuse element, and both ends of the fuse element are protruded from the insulating substrate chip, and lead conductors different from the lead conductor are directly connected to both ends of the fuse element. Resistive fuse characterized by being joined. The fuse with resistance according to claim 2, wherein the fuse element is a different member on both sides of the fuse element bonding film electrode. A surface film electrode for fuse element bonding and a surface film electrode for lead conductor connection are provided on the surface side of the insulating substrate chip with a film resistance and a predetermined film resistance distance therebetween, and the fuse element bonding is provided on the back surface side of the insulating substrate chip. A fuse element joining back membrane electrode conducted through a through hole to the surface membrane electrode, and a lead conductor joining back membrane electrode conducted through the through hole to the lead conductor connecting surface membrane electrode. The fuse element is connected to the lead film connecting back film electrode, and a fuse element is joined to the tip of a lead conductor different from the lead conductor, and the fuse element part separated from the joint part by a predetermined distance is the fuse element. A fuse with resistance, wherein the fuse is joined to a back membrane electrode for joining. A surface film electrode for fuse element bonding and a surface film electrode for lead conductor connection are provided on the surface side of the insulating substrate chip with a film resistance and a predetermined film resistance distance therebetween, and the fuse element bonding is provided on the back surface side of the insulating substrate chip. A fuse element joining back membrane electrode conducted through a through hole to the surface membrane electrode, and a lead conductor joining back membrane electrode conducted through the through hole to the lead conductor connecting surface membrane electrode. The fuse element is joined to the lead conductor connecting back membrane electrode, the middle of the fuse element is joined to the fuse element joining back membrane electrode, and a lead conductor different from the lead conductor is connected to each end of the fuse element. Resistive fuse, characterized by 6. The resistance fuse according to claim 5, wherein the fuse element is a different member on both sides of the fuse element bonding film electrode. 7. The lead conductor tip joined to the end of the fuse element is bent at a substantially right angle with respect to the fuse element, and the bent part is joined to the end of the fuse element. Fuses with resistors as described. 8. The resistor-equipped fuse according to claim 1, wherein the fuse is sealed with a resin mold or a case so as to include a joint portion between the insulating substrate chip and the fuse element and the lead conductor.

Images