TW201517106A - Protection element - Google Patents

Abstract

The purposes of the present invention are: to maintain the stability of a flux; to improve the quick fusing properties of a fusible conductor; and to reduce the thickness of a protection element. This protection element is provided with: an insulating substrate (11); a heat-generating body (14); a heat-generating body lead-out electrode (16) that is electrically connected to the heat-generating body (14); first and second electrodes (12, 13) that are provided on the insulating substrate (11); a fusible conductor (17) that is connected from the heat-generating body lead-out electrode (16) to the first and second electrodes (12, 13) and fuses the current pass between the first electrode (12) and the second electrode (13) when heated; a flux (18) that is provided between the insulating substrate (11) and the fusible conductor (17); and a cover member (21) that protects the insulating substrate (11).

Description

Protective component

The present invention relates to a protection element that is placed on a current path to interrupt the current path when it is abnormal. The present application claims priority on the basis of Japanese Patent Application No. 2013-172630, filed on Aug.

Most of the secondary batteries that can be used for charging and reuse are processed into battery packs and then supplied to the user. In particular, in lithium ion secondary batteries with high weight and energy density, in order to ensure the safety of users and electronic equipment, several protection circuits such as overcharge protection and overdischarge protection are generally built into the battery pack, and the specific conditions will be The output of the battery pack is occluded.

Such a protection element has an ON/OFF output by using a FET switch built in a battery pack to perform an overcharge protection or an overdischarge protection operation of the battery pack. However, even if the FET switch is short-circuited for some reason, when a lightning surge or the like is applied and an instantaneous large current flows, or the output voltage abnormally drops due to the life of the battery cell or vice versa, the battery pack or Electronic machines must be protected from accidents such as fire. Therefore, a protective element is used which is constructed of a fuse element having a function of blocking a current path in response to an external signal in order to safely interrupt the output of the battery cell regardless of any abnormal state that can be assumed above.

As shown in FIG. 10(A) and FIG. 10(B), as a protective element 80 for a protective circuit for a lithium ion secondary battery or the like, a protective element has been proposed which is connected to a current path. The first and second electrodes 81 and 82 are connected to the fusible conductor 83 to form a part of the current path, and the self-heating due to overcurrent or the heating element 84 provided inside the protection element 80 fuses the current path. Conductor 83. In the protective element 80, as shown in FIG. 11, the molten liquid-like soluble conductor 83 is collected on the heat generating body extraction electrode 85 which is provided on the heat generating body 84 through the insulating layer and is electrically connected to the heat generating body 84 or The first and second electrodes 81, 82 block the current path.

Further, in the protective element 80 shown in FIG. 10, in order to prevent melting by heating during reflow soldering or the like, a lead-containing high melting point solder having a melting point of 300 ° C or higher is generally used as the soluble conductor 83. Further, when the meltable conductor 83 is heated, the oxidation progresses and the melting is inhibited. Therefore, in order to remove the oxide film formed on the meltable conductor 83 and improve the wettability of the meltable conductor 83, the flux 86 is laminated.

[Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-170802

Here, in the fusible conductor 83, since the central portion overlapping the heating element 14 is the highest temperature and a large number of molten conductors are aggregated on the heating element extraction electrode 85, it is preferable that the flux 86 is also held at the center portion. However, the flux 86 sometimes deflects left and right on the surface of the fusible conductor. Therefore, the flux 86 is required to be stably held substantially at the center of the fusible conductor 83.

As a countermeasure against this, there is proposed a protective member which is provided on the inner side of the top surface of the cover member 87 inside the protective protective member 80 to provide a convex portion 88 for holding the flux 86 provided on the fusible conductor 83 at a predetermined position ( Refer to Patent Document 1).

The convex portion 88 provided on the inner side of the top surface of the cover member 87 is in contact with the flux 86, and The tension acts on the flux 86, and the flux 86 can be stably held on the surface of the fusible conductor 83 at a predetermined position corresponding to the position at which the convex portion 88 is formed.

With the progress of miniaturization and thinning of electronic devices in recent years, protective devices mounted on various electronic devices are also required to be smaller and thinner. Here, in the protective element in which the convex portion 88 is provided on the inner side of the top surface of the lid member 87, the thickness of the lid member 87 is increased correspondingly by providing the convex portion 88, and it is difficult to reduce the thickness of the entire protective element.

Further, as shown in Fig. 12, when the thickness of the cover member 87 is made thin, the top surface of the convex portion 88 or the cover member 87 comes into contact with the flux 86 or the melted conductive conductor 83, resulting in heat being covered by the cover member 87 or convex. The portion 88 is taken away and the fusible conductor 83 cannot be quickly melted.

Therefore, in the lid member 87, it is necessary to secure a space for avoiding contact between the convex portion 88 and the melted conductor after melting, and there is a limit in thickness reduction.

Therefore, an object of the present invention is to provide a protective element capable of stably holding a flux at a predetermined position, improving the rapid fusibility of a meltable conductor, and reducing the thickness of a protective element.

In order to solve the above problems, the protective element of the present invention includes: an insulating substrate; a heating element; a heating element extraction electrode electrically connected to the heating element; and first and second electrodes provided on the insulating substrate; and a fusible conductor The heating element extraction electrode is connected across the first and second electrodes, and fuses a current path between the first electrode and the second electrode by heating; a flux is provided between the insulating substrate and the fusible conductor And a cover member that protects the above insulating substrate.

According to the present invention, the flux is provided between the insulating substrate and the fusible conductor When the melting position of the fusible conductor is oxidized and heated by the heating element, oxidation prevention and wettability can be improved, and the fuse can be quickly and surely blown.

Further, the flux is provided on the surface of the insulating substrate between the first electrode and the heating element extraction electrode, and between the second electrode and the heating element extraction electrode, and the first and second electrodes and the The fuse conductor is disposed in contact with each other so that it can be stably held by the tension.

Further, according to the present invention, since the flux is held between the meltable conductor and the insulating substrate, it is not necessary to provide the convex portion on the top surface portion of the cover member, and the height can be reduced.

1‧‧‧Protection components

11‧‧‧Insert substrate

12‧‧‧1st electrode

13‧‧‧2nd electrode

14‧‧‧heating body

15‧‧‧Insulating components

16‧‧‧heating body extraction electrode

17‧‧‧Solid conductor

18‧‧‧ Flux

19‧‧‧1st heating element electrode

20‧‧‧2nd heating element electrode

21‧‧‧Cover components

21a‧‧‧ Side section

21b‧‧‧ top face

23‧‧‧ recess

24‧‧‧ Keep the wall

25‧‧‧ convex

30‧‧‧Battery pack

31~34‧‧‧ battery unit

36‧‧‧Detection circuit

37‧‧‧ Current control components

40‧‧‧Charge and discharge control circuit

41,42‧‧‧ Current control components

43‧‧‧Control Department

45‧‧‧Charging device

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a protective member to which the present invention is applied, (A) is a plan view, (B) is a cross-sectional view before fusing, and (C) is a cross-sectional view after fusing.

Fig. 2 is a view showing a modification of the protective element to which the present invention is applied, (A) is a plan view, and (B) is a cross-sectional view.

Fig. 3 is a view showing a modification of the protective element to which the present invention is applied, (A) is a plan view, and (B) is a cross-sectional view.

Fig. 4 is a view showing a modification of the protective element to which the present invention is applied, (A) is a plan view, and (B) is a cross-sectional view.

Fig. 5 is a view showing a modification of the protective element to which the present invention is applied, (A) is a plan view, and (B) is a cross-sectional view.

Fig. 6 is a circuit diagram of a battery pack using a protective element to which the present invention is applied.

Figure 7 is a circuit diagram of a protective element to which the present invention is applied.

Figure 8 is a graph showing the results of the examples.

Figure 9 is a cross-sectional view showing a conventional protective element in comparison with the thickness of a protective element to which the present invention is applied.

Fig. 10 is a view showing a conventional protective element, (A) is a plan view, and (B) is a cross-sectional view before fusing.

Figure 11 is a cross-sectional view of a conventional protective element after being blown.

Fig. 12 is a cross-sectional view showing the fuse of the conventional protective element which is reduced in height.

Hereinafter, the protective element to which the present invention is applied will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below, and various modifications may be made without departing from the scope of the invention. Moreover, the diagram shows that the ratio of each size is different from the real thing. The specific dimensions and the like should be judged by considering the following instructions. Further, of course, the drawings also include portions having different sizes or ratios from each other.

[First form]

As shown in FIG. 1, the protective element 1 to which the present invention is applied includes an insulating substrate 11, a heating element 14 covered with an insulating member 15, a heating element extraction electrode 16 electrically connected to the heating element 14, and a first and second insulating layer 11 provided on the insulating substrate 11. The second electrodes 12 and 13 and the fusible conductor 17 that is connected from the heating element extraction electrode 16 to the first and second electrodes 12 and 13 and that fuses the current path between the first electrode 12 and the second electrode 13 by heating, And a flux 18 disposed between the insulating substrate 11 and the fusible conductor 17.

The insulating substrate 11 is formed into a substantially square shape using an insulating member such as alumina, glass ceramic, mullite, or zirconia. Although the insulating substrate 11 may be made of a material for printing a wiring board such as a glass epoxy substrate or a phenol substrate, it is necessary to pay attention to the temperature at which the meltable conductor 17 is blown.

The heating element 14 has a high electrical conductivity and is electrically conductive due to energization. The member is composed of, for example, W, Mo, Ru, or the like. The heating element 14 can be formed by patterning the alloy or the composition, the powder of the compound, the resin binder or the like, and forming the paste on the insulating substrate 11 by screen printing, and firing it. Formed by other methods. Further, one end of the heating element 14 is continuous with the first heating element electrode 19, and the other end is continuous with the second heating element electrode 20. Further, the heating element 14 is covered by the insulating member 15.

The insulating member 15 covering the heating element 14 is laminated with the heating element extraction electrode 16 so as to overlap the heating element 14. In order to efficiently conduct heat of the heat generating body 14 to the soluble conductor 17, the protective element 1 may be laminated between the heat generating body 14 and the insulating substrate 11. For example, glass can be used as the insulating member 15.

Further, as shown in FIG. 1, the heating element 14 may be formed on the surface side of the insulating substrate 11 on which the first and second electrodes 12 and 13 are provided, or may be formed on the back surface of the insulating substrate 11 on the opposite side to the surface. Further, the heating element 14 may be formed inside the insulating substrate 11. Further, in the heating element 14, the heating element extraction electrode 16 or the soluble conductor 17 may be overlapped, or the heating element extraction electrode 16 or the fusible conductor 17 may be formed in parallel on the surface of the insulating substrate 11. Further, in any case, the heating element 14 is covered by the insulating member 15 when it is necessary to insulate it from the surroundings, and when it is not required to be insulated, it is not covered by the insulating member 15.

The heating element extraction electrode 16 is formed between the first electrode 12 and the second electrode 13 on the insulating substrate 11. Further, one end of the heating element extraction electrode 16 is connected to the first heating element electrode 19, and the first heating element electrode 19 is connected to one end of the heating element 14 via the first heating element electrode 19. Further, the heating element extraction electrode 16 is connected to the second heating element electrode 20 via the heating element 14.

The fusible conductor 17 is made of a material that is rapidly melted by the heat generation of the heating element 14. For example, a low melting point metal such as a lead-free solder containing Sn as a main component can be used very suitably. Also, fusible As the conductor 17, an alloy such as In, Pb, Ag, or Cu may be used, or a laminate of a low melting point metal and a high melting point metal such as Ag, Cu, or an alloy containing the like as a main component may be used.

Both ends of the fusible conductor 17 are connected to the first electrode 12 and the second electrode 13, respectively. The central portion is connected to the heating element lead-out electrode 16. The fusible conductor 17 is connected to the heating element extraction electrode 16 and the first and second electrodes 12 and 13 by solder or the like. The fusible conductor 17 can be easily connected by reflow soldering.

In the protective element 1, the fusible conductor 17 is taken out via the insulating member 15 and the heating element The electrode 16 is provided at a position overlapping the heating element 14. Thereby, the protective member 1 can transfer the heat generated by the heat generating body 14 to the fusible conductor 17 with good efficiency, and quickly melts it.

Further, the protective element 1 is provided with a cover on the insulating substrate 11 for protecting the inside. Member 21. The cover member 21 has a side surface portion 21a and a top surface portion 21b which are connected to the insulating substrate 11.

[flux]

In the protective element 1, a flux 18 is provided between the insulating substrate 11 and the soluble conductor 17. The flux 18 removes the oxide film generated from the fusible conductor 17 while enhancing the wettability of the fusible conductor 17.

Specifically, the flux 18 is shown on the insulating substrate 11 as shown in FIG. 1(A) and (B). The surface is provided between the first electrode 12 and the heating element extraction electrode 16 and between the second electrode 13 and the heating element extraction electrode 16. That is, the flux 18 is electrically connected by the soluble conductor 17, and is disposed between the first electrode of the fusible conductor 17 and the heating element extraction electrode 16 and the second electrode when the current path is blocked.

Thereby, the flux 18 prevents oxidation of the melted position of the fusible conductor 17, Further, when heated by the heating element 14, the oxidation prevention and the wettability can be improved, and the heating can be quickly and surely blown.

Further, the flux 18 is provided on the surface of the insulating substrate 11 on the first electrode. The narrow space between the 12 and the heating element extraction electrode 16 and between the second electrode 13 and the heating element extraction electrode 16 is placed in contact with the first and second electrodes 12 and 13 and the fusible conductor 17, so that it can be borrowed. It is stably held by the tension action.

According to this protective element 1, since the flux 18 is held on the fusible conductor 17 Between the insulating substrate 11 and the insulating substrate 11, the convex portion is not required to be provided on the top surface portion 21b of the lid member 21, and the height can be reduced. That is, as shown in Fig. 1(C), even in the protective element 1, even if the cover member 21 is lowered in height, the molten conductor of the soluble conductor 17 does not contact the cover member 21 and is deprived of heat, and is not hindered. Fuse and quickly interrupt the current path.

[Second form]

Further, as shown in FIGS. 2(A) and (B), the protective element 1 may be between the first electrode 12 of the insulating substrate 11 and the heating element extraction electrode 16, and the second electrode 13 and the heating element extraction electrode 16. The recess 23 is formed therebetween, and the flux 18 is held in the recess 23. The concave portion 23 can be formed by a known microfabrication method corresponding to the material of the insulating substrate 11 such as cutting or etching.

By holding the flux 18 in the recess 23, the protective element 1 can hold a large amount of the flux 18 more stably.

Further, in the protective element 1, the concave portion 23 separates between the first electrode 12 and the heating element extraction electrode 16 and between the second electrode 13 and the heating element extraction electrode 16. Therefore, the protective element 1 can prevent a situation in which the molten conductor of the soluble conductor 17 causes a short circuit between the first electrode 12 and the heat generating body lead-out electrode 16 and between the second electrode 13 and the heat generating body lead-out electrode 16.

[Third form]

Further, the protective element 1 may be on the first electrode 12 of the insulating substrate 11 as shown in FIG. 3(A) and (B). A holding wall 24 for holding the flux 18 is formed between the heating element extraction electrode 16 and the second electrode 13 and the heating element extraction electrode 16. The holding wall 24 is provided at both open ends of the space sandwiched by the first and second electrodes 12, 13 and the heat generating body lead-out electrode 16. Thereby, in the protective element 1, the holding portion of the flux 18 surrounded by the first and second electrodes 12, 13 and the heat generating body lead-out electrode 16 and the pair of holding walls 24 is formed.

The holding wall 24 is connected to the first and second electrodes 12 and 13 and the heating element. 16 contacts, and therefore formed of an insulating material in order to prevent such conduction. For example, the retaining wall 24 can be formed by printing glass.

By providing the retaining wall 24, the protective element 1 can reliably prevent the flux 18 from being The outflow prevents oxidation of the melted position of the soluble conductor 17, and when heated by the heating element 14, it is possible to prevent oxidation and improve wettability, and to quickly and surely melt it.

[Fourth form]

Further, as shown in FIG. 4(A) and (B), the protective element 1 may be provided with a flux 18 between the soluble conductor 17 and the top surface portion 21b of the cover member 21, and formed on the top surface portion 21b of the cover member 21. The convex portion 25 of the flux 18 is maintained. By providing the convex portion 25 on the top surface portion 21b of the cover member 21, the flux 18 provided between the soluble conductor 17 and the top surface portion 21b of the cover member 21 comes into contact with the convex portion 25, whereby tension acts on the flux 18 On the surface of the fusible conductor 17, the flux 18 can be held in a stable amount at a predetermined position corresponding to the position at which the convex portion 25 is formed.

Therefore, the protective element 1 can hold more flux 18 in cooperation with the flux 18 held between the insulating substrate 11 and the fusible conductor 17, and the oxidation prevention and wettability of the soluble conductor 17 can be improved. The fusible conductor 17 is quickly blown. Further, at this time, the protective element 1 may form the above-described concave portion 23 or the holding wall 24 between the first and second electrodes 12, 13 of the insulating substrate 11.

[Fifth form]

Further, as shown in FIG. 5, the protective element 1 may be formed with the heating element lead-out electrode 16 formed on the top surface portion 21b of the lid member 21, and the flux 18 being provided between the first electrode 12 and the second electrode 13. Since the heating element extraction electrode 16 is provided on the top surface portion 21b of the lid member 21, the space between the first electrode 12 and the second electrode 13 in the protective element 1 is wide, and more flux 18 can be held. Further, the protective element 1 may also form the above-described concave portion 23 or holding wall 24 on the insulating substrate 11.

In this case, although the heating element 14 may be formed on the surface of the insulating substrate 11 and covered by the insulating member 15, the insulating substrate 11 may be formed on the back surface or inside of the insulating substrate 11 or the top surface portion 21b of the cover member 21. The surface is broad and flat, while retaining more flux 18.

[How to use protective components]

Such a protective element 1 is used, for example, as a circuit incorporated in a battery pack 30 of a lithium ion secondary battery as shown in FIG. The battery pack 30 has, for example, a battery stack 35 composed of battery cells 31 to 34 of a total of four lithium ion secondary batteries.

The battery pack 30 includes a battery stack 35, a charge and discharge control circuit 40 for controlling charge and discharge of the battery stack 35, and a protective element 1 of the present invention applied to the battery pack 35 in an abnormal state, and the battery cells 31 to 34 are detected. The voltage detecting circuit 36 and the current detecting element 37 that controls the operation of the protective element 1 are controlled by the detection result of the corresponding detecting circuit 36.

The battery stack 35 is required to be connected in series in order to protect the battery cells 31 to 34 from being overcharged and overdischarged, and is detachably connected to the charging via the positive terminal 30a and the negative terminal 30b of the battery pack 30. The device 45 is applied with a charging voltage from the charging device 45. The positive terminal 30a and the negative terminal of the battery pack 30 which are charged by the charging device 45 30b is connected to an electronic device that operates on a battery to operate the electronic device.

The charge and discharge control circuit 40 is provided to flow from the battery stack 35 to the charging device 45 The current path of the current is connected in series by two current control elements 41, 42 and a control unit 43 that controls the operation of the current control elements 41, 42. The current control elements 41, 42 are composed of, for example, field effect transistors (hereinafter referred to as FETs), and the control unit 43 controls the gate voltage to control the conduction and the interruption of the current path of the battery stack 35. The control unit 43 operates by receiving power supply from the charging device 45, and controls the operation of the current control elements 41 and 42 so as to interrupt the current path when the battery stack 35 is over-discharged or overcharged in response to the detection result of the detection circuit 36.

The protection element 1 is connected, for example, to the battery stack 35 and the charge and discharge control circuit 40. The operation of the charge and discharge current path is controlled by the current control element 37.

The detecting circuit 36 is connected to each of the battery cells 31 to 34 to detect each battery cell. The voltage values of the elements 31 to 34 are supplied to the control unit 43 of the charge and discharge control circuit 40. Further, the detection circuit 36 outputs a control signal for controlling the current control element 37 when any one of the battery cells 31 to 34 becomes an overcharge voltage or an overdischarge voltage.

The current control element 37 is composed of, for example, an FET, by the slave detection circuit 36. The output detection signal, when the voltage value of the battery cells 31-34 becomes a voltage exceeding a predetermined over-discharge or over-charge state, causes the protection element 1 to operate to control the charge and discharge current path of the battery stack 35 regardless of the current control element Why are the switching actions of 41, 42 blocked?

The protective element of the present invention is applied to the battery pack 30 constructed as above 1 has the circuit structure as shown in FIG. In other words, the protective element 1 is a circuit structure composed of a fusible conductor 17 connected in series via a heating element extraction electrode 16 and a heating element 14 which is heated by a connection point via the soluble conductor 17 to heat the meltable conductor 17 . Also, in the protective element 1, for example, fusible The conductor 17 is connected in series to the charge and discharge current path, and the heat generating body 14 is connected to the current control element 37. The first electrode 12 on one end of the soluble conductor 17 is connected to one end of the charge and discharge current path, and the second electrode 13 on the other end of the soluble conductor 17 is connected to the other end of the charge and discharge current path. Further, one end of the heating element 14 is connected to the heating element extraction electrode 16 and the fusible conductor 17 via the first heating element electrode 19, and the other end is connected to the current control element 37 via the second heating element electrode 20.

The detecting circuit 36 detects an abnormal voltage of any of the battery cells 31 to 34 At this time, the current control element 37 outputs an occlusion signal. Next, the current control element 37 controls the current to energize the heating element 14. The current flows from the battery stack 35 through the first electrode 12, the soluble conductor 17, and the heat generating body lead-out electrode 16, whereby the heat generating body 14 starts to generate heat. The protective element 1 fuses the soluble conductor 17 by the heat generated by the heating element 14, and blocks the charge and discharge current path. At this time, since the flux 18 is held between the soluble conductor 17 and the insulating substrate 11 in the protective element 1, the oxidation of the melted conductor 17 is prevented from being oxidized, and the heating element 14 is heated to prevent oxidation. The increase in wettability quickly and surely melts it (Fig. 1(C)).

Further, the protective element 1 is blown to the heat generating body 14 by the fusible conductor 17 Since the power supply path is also blocked, the heat generation of the heating element 14 is stopped.

According to this protective element 1, since the flux 18 is held in the fusible conductor 17 Since the insulating substrate 11 is disposed between the insulating substrates 11, it is not necessary to provide a convex portion on the top surface portion 21b of the lid member 21, and the height can be reduced. That is, as shown in Fig. 1(C), even in the protective element 1, even if the cover member 21 is lowered in height, the molten conductor of the soluble conductor 17 does not contact the cover member 21 and is deprived of heat, and is not hindered. Fuse and quickly interrupt the current path.

Further, the protective element of the present invention is not limited to the use of a lithium ion secondary battery The pool package can of course be applied to various applications requiring interruption of the current path due to electrical signals.

[Examples]

Next, an embodiment of the present invention will be described. In the present embodiment, the conventional protective element 80 shown in FIG. 10 and the protective element 1 to which the present invention is applied as shown in FIG. 1 are used to measure and evaluate the fusing time and thickness of the fusible conductor. The measurement of the melting time was carried out before and after the high temperature and high humidity test. The number of samples used for each measurement is eight in each of the conventional protective element 80 and the protective element 1 to which the present invention is applied. Moreover, the measurement of the thinning is to measure and compare the thickness of the protective element.

As shown in Fig. 8, in the conventional protective element 80, after comparing the samples in the initial stage before the high temperature and high humidity test and the samples after the high temperature and high humidity test, the operation time was increased by an average of 50%. Further, in the conventional protective element 80, the unevenness of the operation time of each sample also became large before and after the high-temperature and high-humidity test.

This is because, in the conventional protective element 80, since the flux is held on the surface of the soluble conductor 17, oxidation can be prevented, but the oxidation progresses in the fusing position between the first and second electrodes and the electrode of the heating element. And make the blow time increase.

On the other hand, in the protective element 1 to which the present invention is applied, it is understood that the sample after the high temperature and high humidity test and the sample after the high temperature and high humidity test have an average operation time of 10%. Further, in the protective element 1 to which the present invention is applied, the variation in the unevenness of the operation time of each sample is small before and after the high-temperature and high-humidity test.

This is because, in the protective element 1 to which the present invention is applied, since the flux is held in correspondence with the fusing position between the first and second electrodes and the heating element lead-out electrode, oxidation of the fusible conductor at the fusing position can be prevented, and It can be quickly melted in conjunction with the improvement of the wettability caused by the flux.

Moreover, as shown in FIG. 9, the conventional protective element 80 is provided for the cover structure. The flux between the member and the fusible conductor is held at a predetermined position, and a convex portion is formed on the top surface portion of the cover member. Therefore, the entire device becomes thick, which hinders the reduction in thickness. On the other hand, in the protective element 1 to which the present invention is applied, since the flux is held between the fusible conductor and the insulating substrate, it is not necessary to provide the convex portion on the top surface portion of the cover member, so that the thickness of the entire element can be made conventional. The protection element 80 is cut by 10 to 20%.

1‧‧‧Protection components

11‧‧‧Insert substrate

12‧‧‧1st electrode

13‧‧‧2nd electrode

14‧‧‧heating body

15‧‧‧Insulating components

16‧‧‧heating body extraction electrode

17‧‧‧Solid conductor

18‧‧‧ Flux

19‧‧‧1st heating element electrode

20‧‧‧2nd heating element electrode

21‧‧‧Cover components

21a‧‧‧ Side section

21b‧‧‧ top face

Claims (13)

A protective element comprising: an insulating substrate; a heating element; a heating element extraction electrode electrically connected to the heating element; first and second electrodes provided on the insulating substrate; and a fusible conductor extending from the heating element lead electrode The first and second electrodes are connected to each other, and a current path between the first electrode and the second electrode is melted by heating; a flux is provided between the insulating substrate and the soluble conductor; and a cover member protects the above Insulating substrate. The protective element according to claim 1, wherein the heating element extraction electrode is formed between the first electrode and the second electrode on the insulating substrate, and the flux is provided on the first electrode and the first electrode. The heating element is taken between the electrodes and between the second electrode and the heating element extraction electrode. The protective element according to claim 1 or 2, wherein the flux is held in a concave portion formed in the insulating substrate. A protective member according to claim 1 or 2, wherein a retaining wall for holding the flux at a predetermined position is provided. The protective element according to claim 1, wherein the heating element extraction electrode is formed on a top surface of the cover member, and the flux is provided between the first electrode and the second electrode. The protective element of claim 5, wherein the flux is maintained in formation a recess in the insulating substrate. A protective member according to claim 5, wherein a retaining wall for holding the flux at a predetermined position is provided. A protective member according to claim 1 or 2, wherein a flux is provided between the surface of the member and the cover member; and the cover member is provided with a protrusion for holding the flux on the surface of the member. unit. A protective element according to claim 3, wherein a flux is provided between the surface of the element and the cover member; and the cover member is provided with a convex portion for holding the flux on the surface of the element. A protective element according to claim 4, wherein a flux is provided between the surface of the element and the cover member; and the cover member is provided with a convex portion for holding the flux on the surface of the element. A protective member according to claim 1 or 2, comprising: a cover member for protecting the insulating substrate; and a top surface of the cover member is formed flat. A protective member according to claim 3, comprising: a cover member for protecting the insulating substrate; and a top surface of the cover member is formed flat. A protective member according to claim 4, comprising: a cover member for protecting the insulating substrate; and a top surface of the cover member is formed flat.