TWI585800B - Protective components and battery pack - Google Patents

Description

Protection component and battery pack

The present invention relates to a protection element that protects a circuit connected to a current path by blowing a current path. The present application claims priority on the basis of Japanese Patent Application No. 2012-171332, filed on Jan.

Most of the rechargeable and reusable secondary batteries are processed into a battery pack and supplied to the user. In particular, in a lithium ion secondary battery having a high weight and energy density, in order to secure the safety of the user and the electronic device, in general, a plurality of protection circuits such as overcharge protection and overdischarge protection are built in the battery pack. And has the function of blocking the output of the battery pack under certain circumstances.

In most electronic devices using lithium ion secondary batteries, ON/OFF (on/off) of the output is performed by using a FET (Field Effect Transistor) switch built in the battery pack. Perform overcharge protection or overdischarge protection of the battery pack. However, even when the FET switch is short-circuited by some reason, the output voltage is abnormally lowered when a large current flows instantaneously due to a lightning surge or the like, or the output voltage is abnormally lowered due to the life of the battery unit, or On the contrary, when the output of excessive abnormal voltage is exceeded, it is necessary to protect the battery pack or the electronic device from accidents such as fire. Therefore, in any abnormal state that can be assumed, in order to safely block the output of the battery unit, the use has A protective element consisting of a fuse element that blocks the function of the current path.

As a protective element applied to a protective circuit for a lithium ion secondary battery or the like, as described in Patent Document 1, generally, a structure is provided in which a heat generating body is provided inside the protective element, and a current is blown by heat generation of the heat generating body. A fusible conductor on the path.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-3665

In the protective element described in Patent Document 1, the meltable conductor (fuse) has a current capacity of at most about 15 A in order to be used for a mobile phone or a personal computer having a low current capacity. The use of lithium ion secondary batteries has been expanding in recent years, and the use of larger currents, for example, has been carried out using power tools such as electric screwdrivers, hybrid electric vehicles, electric vehicles, and electric auxiliary bicycles. In such applications, especially at the time of startup, there are cases where a large current of more than 10A to 100A is circulated. It is desirable to have a protective element that corresponds to such a large current capacity.

In order to realize a protection element corresponding to a large current, it is only necessary to increase the cross-sectional area of the fusible conductor. When a Sn/Ag/Cu solder which is formed into a line shape of 1.6 mmφ is used, a current capacity of about 50 A can be obtained. However, in addition to the case where the protective element is blown by the overcurrent state, it is also necessary to detect the overvoltage state of the battery cell, and the current flows to the heat generating body formed of the resistor body, and the meltable conductor is cut by the heat generation. However, in the case of the "thick" fusible conductor, there is a problem in that the heat conduction from the heating element is lowered, and it becomes difficult to stably melt the fusible conductor.

Therefore, it is an object to obtain a protective element which ensures the current capacity at the time of overcurrent protection, and which can be stably blown by heat generation of the heat generating body.

As means for solving the above problems, the protective element of the present invention has: An insulating substrate; a heating element laminated on the insulating substrate; and an insulating member laminated on the insulating substrate so as to cover at least the heating element; the first and second electrodes; and the heating element extraction electrode stacked in a manner overlapping the heating element Above the insulating member, the current path between the first and second electrodes and one of the terminals of the heating element are electrically connected; and the fusible conductor is formed by the self-heating element extracting electrode to the first and second electrodes The layer is laminated, and the current path between the first electrode and the second electrode is blown by heating. Further, the fusible conductive system overlaps the thin portion having a small thickness in a concave portion of the heating element, and the other portion is a thick portion having a thickness thicker than the thin portion and having substantially the same current capacity as the thin portion. The thin portion can be easily melted by the heat of the heating element.

Preferably, the protective element of the present invention further includes a support member disposed to support at least a portion of the thick portion of the thin portion adjacent to the insulating substrate, having a metal layer at least on the surface, and thermally insulating the insulating substrate .

Preferably, the protective element of the present invention further includes: a molten solder discharge electrode that is in contact with the thin portion of the soluble conductor and reaches the insulating substrate through the insulating member; and the receiving electrode is formed on the insulating substrate and is connected with the molten solder Drain the electrode.

The battery pack of the present invention includes one or more battery cells; a protection element connected to block a current flowing through the battery cells; and a current control element that detects a current value of the battery cells and controls a current of the heat protection elements. Further, the protective element has an insulating substrate, a heat generating body laminated on the insulating substrate, an insulating member laminated on the insulating substrate so as to cover at least the heat generating body, first and second electrodes, and a heat generating body lead electrode Superimposed on the insulating member, laminated on the upper surface of the insulating member, electrically connected to the current path between the first and second electrodes and one of the terminals of the heating element; and the fusible conductor which leads to the electrode from the heating element 1 and the second electrode are layered, and the current path between the first electrode and the second electrode is blown by heating The fusible guiding system is composed of a thick portion and a thin portion which are formed in a concave shape and are thin and flat in a portion overlapping the heating element.

In the present invention, the fusible conductor is a thin portion having a thin thickness which is concave in a portion of the heat generating body, and the other portion is a thick wall having a thickness thicker than the thin portion and having substantially the same current capacity as the thin portion. Therefore, the current capacity of the non-fusible conductor is lowered, and the fusible conductor can be easily blown by the heat of the heating element.

Further, since the support member having the metal layer at least on the surface and thermally insulating the insulating substrate is provided, the heat generated by the heat generating body is concentrated on the thin portion of the soluble conductor, and the melting of the fusible conductor is promoted, and the support member is further supported by the support member. The wettability is guided and the solder melted by the heat generation of the heating element is accommodated, so that stable melting characteristics can be achieved.

Moreover, the solder melted by the heat generated by the heat generating body can be guided by the wettability of the molten solder discharge electrode and can be accommodated in the storage electrode, so that stable melting characteristics can be achieved.

2‧‧‧Separate electrodes

3‧‧‧Support members

4‧‧‧ receiving electrode

5‧‧‧ molten solder discharge electrode

8‧‧‧ Space

10‧‧‧Protection components

11‧‧‧Insert substrate

12 (A1), 12 (A2) ‧ ‧ 1st and 2nd electrodes

13‧‧‧Solid conductor

13a‧‧‧ Thick Wall

13b‧‧‧thin wall

13c‧‧‧Boundary position

13d‧‧‧Central Department

14‧‧‧heating body

15‧‧‧Insulating components

16‧‧‧heating body extraction electrode

18 (P1), 18 (P2) ‧ ‧ heating body electrodes

18a (P1), 18a (P2) ‧ ‧ electrodes

20‧‧‧Battery Pack

20a‧‧‧positive terminal

20b‧‧‧Negative terminal

21~24‧‧‧ battery unit

25‧‧‧Battery stack

26‧‧‧Detection circuit

27, 31, 32‧‧‧ Current Control Components

30‧‧‧Charge and discharge control circuit

33‧‧‧Control Department

35‧‧‧Charging device

40‧‧‧Pushing pin

Figure 1 (A) is a plan view of a protective element to which the present invention is applied. Fig. 1(B) is a cross-sectional view taken along line AA' of Fig. 1(A). Fig. 1(C) is a cross-sectional view showing a state in which a fusible conductor is blown.

Fig. 2 is a block diagram showing an application example of a protective element to which the present invention is applied.

Fig. 3 is a view showing an example of a circuit configuration of a protective element to which the present invention is applied.

Fig. 4 (A) is a plan view showing a protective element according to another embodiment of the present invention. Fig. 4(B) is a cross-sectional view taken along line AA' of Fig. 4(A). Fig. 4(C) is a cross-sectional view showing the meltable conductor in a molten state.

5(A) to (C) are diagrams for explaining the manufacture of a protective element according to another embodiment of the present invention. Top view of the program.

Fig. 6(A) is a plan view showing the combination of the protective elements of the two embodiments of the present invention. Fig. 6(B) is a cross-sectional view taken along line AA' of Fig. 6(A).

Fig. 7(A) is a plan view showing a protective element according to a modification of the present invention. Fig. 7(B) is a cross-sectional view taken along line AA' of Fig. 7(A).

Fig. 8 is a view conceptually showing a state in which a fusible conductor of a protective element according to a modification of the present invention is blown. Fig. 8(A) is a view showing a state in which the thin portion of the fusible conductor starts to be melted, and the molten solder flows in the direction of the arrow; and Fig. 8(B) is a view showing a state in which the thin portion is melted.

9(A) to (C) are views for explaining the order of making a fusible conductor for a protective element of a modified example of the present invention.

Hereinafter, the form for carrying out the present invention will be described in detail with reference to the drawings. It is a matter of course that the present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention.

[Composition of protective components]

As shown in FIG. 1(A) and FIG. 1(B), the protective element 10 includes an insulating substrate 11 and a heat generating body 14 laminated on the insulating substrate 11 and covered with an insulating member 15; first and second electrodes 12 (A1) and 12 (A2) are formed at both ends of the insulating substrate 11; the heating element extraction electrode 16 is laminated on the insulating member 15 so as to overlap the heating element 14; the soluble conductor 13 has both ends The first and second electrodes 12 (A1) and 12 (A2) are connected to each other, and the central portion is connected to the heating element extraction electrode. In order to cause an electric current to flow through the heating element and generate heat, the heating element electrodes 18 (P1) and 18 (P2) connected to the power source are connected to both ends of the heating element 14. The fusible conductor 13 is, for example, a round wire of 1.6 mm Φ. The thick portion 13a is formed by a thin portion 13b which is a portion where the heating element 14 is opposed to the heating element 14, and is thinner than the thick portion 13a so as to be substantially uniform in thickness. Forming. The thickness of the thin portion 13b is, for example, 1/2 of the thickness (thickness) of the thick portion 13a. Further, the cross-sectional areas of the thick portion 13a and the thin portion 13b are preferably substantially the same. The thin portion 13b of the fusible conductor 13 is electrically connected to the heating element extraction electrode 16.

In this manner, by forming the thin portion 13b which is thinned at the position where the meltable conductor 13 is superposed on the heat generating body 14, the heat conduction in the thickness direction of the thin portion 13b is improved, so that the heat generated by the heat generating body 14 can be generated. The fusible conductor 13 is easily blown. Further, by forming the thin portion 13b in a flat shape, the contact area with the overlapping portion of the heating element 14 can be increased, and the heat from the heating element 14 can be efficiently transmitted, and stable melting characteristics can be realized. Further, when the cross-sectional areas of the thick portion 13a and the thin portion 13b are substantially the same, the current capacity of the meltable conductor 13 is constant, and the cross-sectional area and the fusible conductor corresponding to the energizing direction of the fusible conductor 13 can be circulated. 13 material (specific resistance) current.

The insulating substrate 11 is formed of, for example, an insulating member such as alumina, glass ceramic, mullite, or zirconia. Further, a material for a printed circuit board such as a glass epoxy substrate or a phenol substrate may be used, but it is necessary to pay attention to the temperature at which the fuse is blown.

The two electrodes 12 (A1) and 12 (A2) are connected to the inside of the protective element 10 to connect the fusible conductor 13, and are connected to an external circuit via the two electrodes 12 (A1) and 12 (A2). The two electrodes 12 (A1) and 12 (A2) may be formed on the insulating substrate 11 or may be formed as an insulating material made of an epoxy resin or the like integrated with the insulating substrate 11.

The heating element 14 is a member having a relatively high electric resistance value and which generates heat when energized, and is made of, for example, W, Mo, Ru, or the like. By mixing the alloy or composition, the powder of the compound, the resin binder, etc., the screen printing technique is used as the paste. The case is formed on the insulating substrate 11 and baked or the like.

The insulating member 15 is disposed so as to cover the heating element 14, and the heating element extraction electrode 16 is disposed to face the heating element 14 via the insulating member 15. Of course, the insulating member 15 may be a laminated substrate in which the heating element 14 is integrally laminated inside.

One end of the heating element extraction electrode 16 is connected to one end of the heating element electrode 18 (P1) and the heating element 14. Further, the other end of the heating element 14 is connected to the other heating element electrode 18 (P2).

The fusible conductor 13 may be a material that is melted and melted by an overcurrent state and heat generated by the heating element 14, and for example, SnAgCu-based Pb-free solder may be used, and BiPbSn may be used. Alloy, BiPb alloy, BiSn alloy, SnPb alloy, PbIn alloy, ZnAl alloy, InSn alloy, PbAgSn alloy, and the like.

Further, the fusible conductor 13 may be a laminate of a high melting point metal composed of Ag or Cu or a metal containing Ag or Cu as a main component, and the low melting point metal is made of Sn. The main component is Pb-free solder or the like.

In order to correspond to a large current capacity, in the protective element of the present invention, a fusible conductor having a large cross-sectional area is used. In the case where the fusible conductor is blown, since the amount of the molten solder is large, it is difficult to reliably block the circuit, and therefore it is necessary to guide to a space in which the molten solder can be accommodated. Further, the thin conductor portion 13b is provided in the fusible conductor 13, and the stress tends to concentrate on the boundary between the thick portion 13a and the thin portion 13b, which causes a problem of mechanical damage.

Therefore, as shown in Figs. 1(A) to (C), the metal support member 3 is formed in a thermal circuit on the individual electrode 2 insulated from the other portions of the insulating substrate 11. The support member 3 is connected to the vicinity of the connection portion between the thick portion 13a of the fusible conductor 13 and the thin portion 13b to support the fusible conductor 13.

As shown in Fig. 1(C), when the meltable conductor 13 is melted, the solder wettability of the support member 3 is larger than that of the insulating member 15 and the insulating substrate 11, and the molten solder is introduced in the direction of the arrow as shown in Fig. 1(C). . Since the space 8 is formed between the lower portion of the fusible conductor 13 and the insulating member 15 and the insulating substrate 11, the support member 3 and the individual electrode 2 are disposed in the space 8, so that a large amount of molten solder can be accommodated. Further, by disposing the support member 3 in the vicinity of the boundary portion between the thin portion 13b of the fusible conductor 13 where the stress is easily concentrated and the thick portion 13a, a weak portion of the mechanical strength is supported to make the fusible conductor 13 Increased strength. In particular, the damage of the fusible conductor 13 can be prevented during the manufacture of the protective element 10, and the manufacturing yield of the protective element 10 can be improved. The individual electrode 2 is formed by, for example, a pattern of Cu or Ag paste, but the individual electrode 2 is not connected to other circuits such that the support member 3 is thermally insulated from other portions. Moreover, since the support member 3 and the storage electrode 4 have a constant heat capacity, a heat storage effect can be expected. When the meltable conductor 13 is melted, the heat generated by the heat generating body 14 reaches the thin portion 13b of the soluble conductor 13 via the insulating member 15. By the heat storage effect of the support member 3 and the individual electrodes 2, the generated heat flows into the support member 3 side, and the heat is prevented from flowing out to the thick portion 13a connected to the thin portion 13b. Therefore, the heat generated by the heat generating body 14 can be concentrated on the thin portion 13b of the soluble conductor 13, and the sintering of the meltable conductor 13 can be stabilized.

The metal support member 3 may be a metal that is easily wetted by solder, and may be formed integrally with the individual electrode 2 using Cu, Ag, Ni, or the like. Since the support member 3 uses a solder having a lower melting point than the soluble conductor 13, it can be easily manufactured. That is, the independent electrode 2 and the other electrodes are simultaneously patterned by the Ag paste on the insulating substrate 11 using an alignment process, and the insulating member 15 is placed and connected. Thereafter, the support member 3 composed of the low-melting solder is formed on the individual electrode 2, and is passed through the reflow step, whereby the fusible conductor 13 can be easily connected.

[How to use protective components]

As shown in FIG. 2, the above protective element 10 is used in a circuit in a battery pack of a lithium ion secondary battery.

For example, the protective element 10 is incorporated into the battery pack 20 having the battery stack 25 composed of the battery cells 21 to 24 of a total of four lithium ion secondary batteries.

The battery pack 20 includes a battery stack 25, a charge and discharge control circuit 30 for controlling charge and discharge of the battery stack 25, a protection element 10 of the present invention, which protects the battery stack 25 and the charge and discharge control circuit 30, and a detection circuit 26 for detecting The voltage of each of the battery cells 21 to 24; and the current control element 27 controls the operation of the protection component 10 based on the detection result of the detection circuit 26.

The battery stack 25 is connected in series with battery cells 21 to 24, and the battery cells 21 to 24 are required to protect the overcharge and overdischarge states, and are detachable via the positive terminal 20a and the negative terminal 20b of the battery pack 20. The ground is connected to the charging device 35, and the charging voltage from the charging device 35 is applied. The positive electrode terminal 20a and the negative electrode terminal 20b of the battery pack 20 that is charged by the charging device 35 are connected to an electronic device that is operated by a battery, whereby the electronic device can be operated.

The charge and discharge control circuit 30 includes two current control elements 31 and 32 connected in series to a current path flowing from the battery stack 25 to the charging device 35, and a control unit 33 that controls the current control elements 31 and 32. action. The current control elements 31 and 32 are composed of, for example, field effect transistors (hereinafter referred to as FETs), and the gate voltage is controlled by the control unit 33, thereby controlling the conduction and blocking of the current path of the battery stack 25. The control unit 33 controls the operation of the current control elements 31 and 32 by receiving power supply from the charging device 35 and operating, and when the battery stack 25 is over-discharged or overcharged based on the detection result obtained by the detection circuit 26, Block the current path.

The protection element 10 is connected, for example, to a charge and discharge current path between the battery stack 25 and the charge and discharge control circuit 30, and its operation is controlled by the current control element 27.

The detection circuit 26 is connected to each of the battery cells 21 to 24, detects the voltage values of the battery cells 21 to 24, and supplies the respective voltage values to the control unit 33 of the charge and discharge control circuit 30. Further, when any one of the battery cells 21 to 24 becomes an overcharge voltage or an overdischarge voltage, the detection circuit 26 outputs a control signal for controlling the current control element 27.

The current control element 27 is controlled by the detection signal outputted from the detection circuit 26 to cause the protection element 10 to operate when the voltage value of the battery cells 21 to 24 becomes a voltage exceeding a specific overdischarge or overcharge state. The switching operation of the current control elements 31, 32 blocks the charge and discharge current path of the battery stack 25.

In the battery pack 20 constituted by the above configuration, the configuration of the protective element 10 will be specifically described.

First, the protective element 10 to which the present invention is applied has, for example, a circuit configuration as shown in FIG. In other words, the protective element 10 is a circuit composed of a fusible conductor 13 connected in series via the heating element extraction electrode 16 and a heating element 14 that is heated by the connection point of the soluble conductor 13 to fuse the soluble conductor 13 Composition. Further, in the protective element 10, for example, the fusible conductor 13 is connected in series to the charge and discharge current path, and the heat generating body 14 is connected to the current control element 27. One of the two electrodes 12, 12 of the protective element 10 is connected to A1 and the other to A2. Further, the heating element extraction electrode 16 and the heating element electrode 18 connected thereto are connected to P1, and the other heating element electrode 18 is connected to P2.

The protective element 10 constructed by such a circuit configuration can achieve low profile, and can reliably fuse the fusible conductor 13 on the current path by the heat generated by the heat generating body 14.

[Other implementations]

As shown in FIG. 4(A) and FIG. 4(B), the protective element 10 of the present invention may be provided with a molten solder discharge electrode 5 and a housing electrode 4; the molten solder discharge electrode 5 is close to the thin portion 13b. The storage electrode 4 is formed by accommodating the molten solder guided by the molten solder discharge electrode 5 on the insulating substrate 11. By providing the molten solder discharge electrode 5 and the storage electrode 4, a large amount of molten solder serving as a meltable conductor of "thick" solder corresponding to a large current is guided, which contributes to the reliable separation of the meltable conductor 13.

The molten solder discharge electrode 5 is formed on the same surface as the heat generating body lead-out electrode 16 formed on the insulating member 15. The molten solder discharge electrode 5 is disposed along the longitudinal direction of the soluble conductor 13, and is connected to the thin portion 13b to the insulating member 15, and is connected to the receiving electrode 4 formed on the insulating substrate 11 through the side surface of the insulating member 15. . The molten solder discharge electrode 5 can also be formed by forming a through-hole electrode from the upper surface of the insulating member 15 toward the back surface side. The lower surface and the side surface of the side surface electrode of the insulating member 15 are connected to the storage electrode 4 by solder. In this manner, the surfaces of the molten solder discharge electrode 5 and the storage electrode 4 are subjected to solder treatment to form a solder fillet.

As shown in Fig. 4(C), when the thin portion 13b of the soluble conductor 13 is melted, capillary flow occurs in the gap between the thin portion 13b of the soluble conductor 13 and the insulating member 15, and the solder is formed along the solder. The molten solder of the corners is discharged from the electrode 5 and guided to the direction in which the electrode 4 is housed. When the area in which the storage electrode 4 is disposed is obtained more than a certain degree, the molten solder is accommodated in the storage electrode 4 due to the wettability of the storage electrode. As described above, by arranging the path for guiding the molten solder and the accommodating portion, even when a large amount of the current-soluble conductive conductor 13 is used, the molten solder can be separated and the circuit can be reliably blocked.

As shown in FIGS. 5(A) to 5(C), the path for accommodating the molten solder in the embodiment can be easily formed by, for example, patterning a metal using a printing technique.

As shown in FIG. 5(A), heat generating body electrodes 18 (P1) and 18 (P2) for supplying electric power to the heat generating body 14 on the insulating substrate 11 are formed, and the receiving electrode 4 is simultaneously formed. The electrodes may form a Cu pattern or may be formed using an Ag paste. As shown in FIG. 5(B), the electrode pattern formed on the insulating substrate 11 is solder-bonded to an insulating member (laminated substrate) 15 in which the heat generating body 14 is laminated. The opposite sides of one pair of the insulating members 15 having the square shape are formed with electrodes 18a (P1), 18a (P2) for supplying electric power to the heating element 14, and molten solder discharge electrodes are formed for the opposite sides of the other pair. 5, 5. As shown in FIG. 5(C), the fusible conductor 13 is placed on the insulating member 15 to be mounted. When the fusible conductor 13 is placed, the heat generating body lead electrode 16 and the molten solder discharge electrode 5 are connected to the thin portion 13b.

In this embodiment, the protective element may be configured in combination with the embodiment described in FIG. That is, as shown in FIGS. 6(A) and 6(B), the support member 3 is formed on the individual electrode 2 formed on the insulating substrate 11, and further, the molten solder discharge electrode 5 is provided on the insulating member 15, and is connected in formation. It is placed on the housing electrode 4 on the insulating substrate 11. Here, the storage electrode 4 is formed in a ring shape, and the pattern is formed so that the individual electrode 2 is disposed at the center portion of the ring, whereby the limited area on the insulating substrate 11 can be effectively utilized. Further, the pattern of the electrodes is of course not limited to this and can be arbitrarily set.

[Modification]

In the case of a protective element corresponding to a large current, the problem of securing a space for accommodating a large amount of molten solder is maximized, and a modification thereof will be described herein.

As shown in FIG. 7(A) and FIG. 7(B), the thin portion 13b of the soluble conductor 13 has a space (recessed portion) for accommodating the insulating member 15 mounted on the insulating substrate 11, but the self-insulating member The space on the 15 side enlarges this space, whereby the molten solder can be accommodated more easily. That is, as shown in Fig. 7(B), the shape of the thin portion 13b of the fusible conductor 13 is curved in such a manner that the boundary portion 13c from the thin portion 13b and the thick portion 13a will be substantially at the same distance from the center portion. 13d is connected to the heating element extraction electrode 16. Then, the central portion 13d can be bent upward toward the boundary position 13c to increase the distance between the boundary position 13c and the vertical direction of the insulating member 15.

As shown in Fig. 8(A), the thin portion 13b of the meltable conductor 13 is melted by being energized to the heat generating body 14, and the molten solder is separated by the space between the boundary position 13c and the insulating member 15, while It is guided to the support member 3 having a large solder wettability. As shown in FIG. 8(B), the molten solder is introduced and housed in the support members 3 on both sides, and is accommodated in the heat generating body lead-out electrode 16.

The fusible conductor 13 having the thin portion 13b formed in the "M" shape in such a cross section can be manufactured, for example, in the following manner.

As shown in Fig. 9(A), the pressing pin 40 is placed at a predetermined position at which the thin portion 13b of the fusible conductor 13 is to be formed, and is moved in the direction of the arrow. As shown in Fig. 9(B), when the pressing pin 40 is pressed against the meltable conductor 13 by a predetermined pressure, the thin portion 13b is linear when the pressing pin 40 is removed by the ductility and rigidity of the metal. Both ends of the fusible conductor 13 are also bent on the side of the pressure. As shown in Fig. 9(C), when the both ends of the curved fusible conductor 13 are pressed in the direction of the arrow so that the thick portions 13a on both sides are linear, the shape of the thin portion 13b becomes It is roughly "M" shaped. In addition, the cross-sectional shape of the meltable conductor 13 of the thin portion 13b in the longitudinal direction is not limited to the above-mentioned "M" shape, and the space for accommodating the molten solder toward the thick portion 13a of the soluble conductor 13 is enlarged. The gist of the matter can be self-evident for any similar shape.

In this modification, of course, the above-described support member 3 and/or the molten solder discharge electrode 5 can be used in combination, and the discharge mechanism of the molten solder can be further ensured, and stable fusing characteristics can be realized.

2‧‧‧Separate electrodes

3‧‧‧Support members

10‧‧‧Protection components

11‧‧‧Insert substrate

12 (A1), 12 (A2) ‧ ‧ 1st and 2nd electrodes

13‧‧‧Solid conductor

13a‧‧‧ Thick Wall

13b‧‧‧thin wall

14‧‧‧heating body

15‧‧‧Insulating components

16‧‧‧heating body extraction electrode

18 (P1), 18 (P2) ‧ ‧ heating body electrodes

18a (P1), 18a (P2) ‧ ‧ electrodes

Claims (11)

A protective element comprising: an insulating substrate; a heating element laminated on the insulating substrate and having a heating element electrode; and an insulating member laminated on the insulating substrate so as to cover at least the heating element; first and second An electrode; a fusible conductor laminated so as to extend across the first and second electrodes from the heating element lead-out electrode, forming a current path between the first electrode and the second electrode, and melting the first electrode by heating a current path between the second electrode and the heating element extraction electrode stacked on the insulating member so as to overlap the heating element, and a current path between the first and second electrodes and the current One of the heating elements is electrically connected to the heating element; the fusible guiding system is composed of a thick portion and a thin portion, and the thin portion is formed in a concave shape and is thin and flat in a portion of the heating element. The protective element of claim 1, further comprising a support member supported by the insulating substrate at least a portion of the thick portion adjacent to the thin portion, and the fusible conductor and the The insulating substrate is disposed to receive a space in which the meltable conductive conductor is housed, and has a metal layer at least on the surface. The support member is thermally insulated from the insulating substrate as claimed in claim 2 of the patent. A protective element according to claim 1, further comprising a molten solder discharge electrode which is close to a thin portion of the soluble conductor and which is passed through the insulating member The insulating substrate is reached. A protective element according to claim 4, further comprising a storage electrode formed on the insulating substrate and connected to the molten solder discharge electrode. The protective element of claim 1, wherein the fusible guiding system is connected to the heating element lead-out electrode in an intermediate portion of the thin-walled portion, and a position from the connecting portion to a boundary between the thin-walled portion and the thick-walled portion A path through which molten solder flows is formed. According to the protective element of the sixth aspect of the invention, the thin-walled portion is formed in an M-shape in a longitudinal direction of the fusible conductor and a cross-sectional shape in the laminating direction. The protective member has a protective material of item 2 or 3 of the patent scope, the support member having a metal material having a melting point lower than the soluble conductor at least on the surface. The low melting point metal material is a low melting point solder as claimed in claim 8 of the patent application. According to the protective element of the first aspect of the patent application, the cross-sectional area of the thin-walled portion and the thick-walled portion is the same. A battery pack comprising: one or more battery cells; a protection element connected in a manner blocking a current flowing through the battery cells; and a current control component detecting a voltage value of the battery cells to control heating of the protection component The protective element has the following members: an insulating substrate; a heating element laminated on the insulating substrate and having a heating body electrode; An insulating member laminated on the insulating substrate so as to cover at least the heating element; first and second electrodes; and a fusible conductor laminated to the first and second electrodes by the self-heating body extraction electrode a current path between the first electrode and the second electrode, which fuses a current path between the first electrode and the second electrode by heating; and a heating element extraction electrode that is laminated so as to overlap the heating element Above the insulating member, a current path between the first and second electrodes and a heating element electrode of the heating element are electrically connected; the fusible guiding system is composed of a thick portion and a thin portion. The thin portion is formed in a concave shape and is thin and flat in a portion of the heat generating body.