Protection element and battery pack

Abstract

To improve an insulating property after fusing of a fuse element.SOLUTION: This is a protection element including an insulating substrate 2, a heating element 5, a first electrode 3 and a second electrode 4, a heating element extraction electrode 6, a first support electrode 7 provided between the first electrode 3 and the heating element extraction electrode 6, a second support electrode 8 provided between the second electrode 4 and the heating element extraction electrode 6, a fusible conductor 10 for blocking heat which is connected across the first support electrode 7, the heating element extraction electrode 6, and the second support electrode 8 and is melted by heat generated by the heating element 5, and a fusible conductor 11 for blocking current, which is connected across the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4 and is fused by self-heating caused by application of an overcurrent exceeding a rating. The fusible conductor 10 and the fusible conductor 11 are connected in series, and a resistance value of the fusible conductor 11 is higher than the resistance value of the fusible conductor 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present technology relates to a protection element that is mounted on a circuit board and cuts off current to at least a part of the circuit board when an abnormality occurs in the circuit board, and a battery pack using the protection element. [Background technology]

[0002] In recent years, lithium-ion batteries have expanded from their use in mobile devices to applications such as electric vehicles (EVs) and storage batteries, and their current capacity is becoming larger. Because these batteries pose a risk of fire in the event of an abnormality, as their capacity increases, the mainstream method of ensuring product safety is to incorporate protection circuits using protective elements.

[0003] There are two types of protective elements: current fuses that protect against overcurrent, and fuses that protect against both overcurrent and overvoltage. Current fuses that protect against overcurrent are connected in series to electrical circuits and immediately cut off the current path when an overcurrent occurs due to an electrical short circuit or other event within the equipment, protecting the wires and equipment that make up the circuit from accidents such as fire. Overcurrent protection fuses have a relatively simple structure, and when an overcurrent flows, the fusible conductor element of the fuse, which has a small cross-sectional area, reaches its melting point due to Joule heat and melts, cutting off the current path.

[0004] Fuses that function as overcurrent protection fuses as well as overvoltage protection fuses are mainly equipped with a heating element that melts when it heats up. Specifically, when an IC that monitors the voltage and temperature of a lithium-ion battery detects an abnormality, it sends a signal to an FET that functions as an ON / OFF switch. When the FET is in the ON state, current begins to flow to the heating element, and the heat generated by the current melts the fuse, cutting off the current path.

[0005] In both overcurrent and overvoltage protection devices, if an abnormality is detected, the device must quickly shut off the circuit for safety reasons. Generally, the protection device is constructed with a thick-film printed circuit board and a fuse element (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-053260 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, lithium-ion batteries and other batteries are expanding from their use in mobile devices to applications such as EVs and storage batteries, and as a result, protective elements are also being required to support higher rated voltages and larger current capacities.

[0008] However, as rated voltages increase, sparks (discharges) are more likely to occur between the electrodes after the fuse element has cut off. Repeated sparks cause tracking, which prevents the current path from being cut off and increases the risk of the fuse not cutting. Therefore, there is a need to improve insulation after the current has been cut off.

[0009] Increasing the volume of the fuse element or the thickness of the conductor on the insulating substrate is one possible way to increase the current capacity, but as the volume of the fuse element increases or the conductor thickness increases, the impact when the fuse element blows becomes more severe, and there is a risk that the insulation properties after blowing will deteriorate due to the adhesion of molten debris, etc. Furthermore, tracking via the molten debris is more likely to occur after the fuse element blows.

[0010] For this reason, with conventional technology, the rated voltage is limited to 80V, and at voltages greater than 80V (for example, 100V or greater), after the current is interrupted, sparks (discharges) may occur across the electrode, insulating substrate, and heating element extraction electrode, which may then cause a tracking phenomenon.

[0011] Fig. 35 shows an example of a conventional high-voltage protection element 100, where (A) is a plan view, (B) is a D-D' cross-sectional view of (A), (C) is a P-P' cross-sectional view of (A), and (D) is a plan view of (A) without the upper case. Fig. 36 shows plan views of the protection element 100 without the upper case, where (A) schematically shows a state in which shutdown has occurred due to self-heating caused by an overcurrent, and (B) and (C) schematically show the state after shutdown.

[0012] As shown in Figures 35 and 36, the protection element 100 includes a pair of upper and lower cases 101, a fuse element 102 made of a fusible conductor, and a fusing member 103 that fuses the fuse element 102. The fusing member 103 includes an insulating substrate 104, a heating element lead electrode 105 connected to the fuse element 102, and a heating element 106 that generates heat when energized and fuses the fuse element 102. The lower case 101a has a pair of fuse terminals 107 and 108 connected to the fuse element 102 and a heating element terminal 109 connected to the heating element 106 mounted on its side edges, and the insulating substrate 104 mounted in its center. One end of the heating element 106 is connected to the heating element lead electrode 105, and the other end is connected to an external power source via the heating element terminal 109.

[0013] The fuse element 102 is connected to the fuse terminals 107, 108 and the heating element lead electrode 105 by a conductive material such as solder. The fuse element 102 is also superimposed on the heating element 106 via an insulating layer and the heating element lead electrode 105. The fuse terminals 107, 108 of the protective element 100 are connected to terminals of an external circuit, so that the fuse element 102 is incorporated into the current path of the external circuit. When current is applied to the heating element 106 from an external power source, the protective element 100 melts the fuse element 102 due to the heat from the heating element 106. When an abnormal current flows through the external circuit, the fuse element 102 melts due to self-heating (Joule heat), thereby interrupting the current path of the external circuit (see FIG. 36(A)).

[0014] As mentioned above, conventional high-voltage protection elements have a rated voltage limit of about 80 V, and at higher voltages, such as 100 V or higher, the blowout impact of fuse element 102 becomes greater, causing soot-like debris 102a from melted fuse element 102 to adhere to the inner surface of the case or the surface of the insulating substrate (see FIG. 36(B)). As a result, as shown in FIG. 36(C), after fuse element 102 blows, a spark (discharge) occurs between fuse terminal 107, insulating substrate 104, and fuse terminal 108, raising the risk of subsequent tracking.

[0015] Therefore, an object of the present technology is to provide a protection element that can improve insulation after a fuse element has blown, and a battery pack using the protection element. [Means for solving the problem]

[0016] In order to solve the above-described problems, a protection element according to the present technology includes an insulating substrate, a heating element provided on the insulating substrate, a first electrode and a second electrode, a heating element extraction electrode electrically connected to the heating element on a current path between the first electrode and the second electrode, a first support electrode provided on the insulating substrate and between the first electrode and the heating element extraction electrode, and a second support electrode provided between the second electrode and the heating element extraction electrode, and is connected across the first support electrode, the heating element extraction electrode, and the second support electrode, and when heat is generated by the heating element, at least the heating element extraction electrode and the first support electrode are electrically connected. and a current interruption soluble conductor that is connected between the first supporting electrode and the first electrode and between the second supporting electrode and the second electrode, and that melts at least between the first electrode and the first supporting electrode or between the second electrode and the second supporting electrode due to self-heating caused by the passage of an overcurrent exceeding the rated value, thereby interrupting the current path. The heat interruption soluble conductor and the current interruption soluble conductor are connected in series, and the resistance value of the current interruption soluble conductor is higher than the resistance value of the heat interruption soluble conductor.

[0017] In addition, a battery pack according to the present technology includes one or more battery cells, a protection element connected to a charge / discharge path of the battery cell and blocking the charge / discharge path, and a current control element that detects a voltage value of the battery cell and controls current flow to the protection element, and the protection element is the protection element described above. [Effects of the Invention]

[0018] According to this technology, the functions of the soluble conductors are separated by providing a heat-interrupting soluble conductor that fuses to interrupt the current path due to heat generated by a heating element and a current-interrupting soluble conductor that fuses to interrupt the current path due to self-heating caused by the passage of an overcurrent exceeding the rated voltage. The resistance of the current-interrupting soluble conductor is higher than that of the heat-interrupting soluble conductor. This allows for a larger current capacity while reducing the volume of the current-interrupting soluble conductor. Therefore, even with a higher rated voltage, the occurrence of sparks and tracking after current interruption can be suppressed. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 shows a protection element to which this technology is applied, where (A) is a plan view, (B) is a plan view showing the upper case omitted, and (C) is a cross-sectional view taken along the line D-D' of (A). [Figure 2] FIG. 2 shows the upper and lower cases, where (A) is a bottom view of the upper case, (B) is a plan view of the lower case, and (C) is a cross-sectional view showing the upper and lower cases butted together. [Figure 3] FIG. 3 is a perspective view showing an example of the configuration of a heat interruption fusible conductor and a current interruption fusible conductor, where (A) shows a laminated structure, and (B) and (C) show coated structures. [Figure 4] 4A and 4B are diagrams showing the state in which the heat generation cutoff fusible conductor in the protection element shown in FIG. 1 has melted, with the case omitted, where (A) is a plan view, (B) is a cross-sectional view, and (C) is a circuit diagram. [Figure 5] FIG. 5 is a circuit diagram showing an example of the configuration of a battery pack. [Figure 6] FIG. 6 is a circuit diagram of the protection element. [Figure 7] 7A and 7B are diagrams showing a state in which one of the current interrupting fusible conductors has melted in the protection element shown in FIG. 1, with the case omitted, where (A) is a plan view and (B) is a circuit diagram. [Figure 8] 8A and 8B are diagrams showing a state in which both current interrupting fusible conductors in the protection element shown in FIG. 1 are melted, with the case omitted, where (A) is a plan view and (B) is a circuit diagram. [Figure 9] FIG. 9 is a plan view showing a protection element in which a plurality of current interrupting soluble conductors are provided between the first support electrode and the first electrode and between the second support electrode and the second electrode. [Figure 10] FIG. 10 is a plan view showing a protection element in which a through hole is provided in a current interrupting soluble conductor between the first support electrode and the first electrode and between the second support electrode and the second electrode. [Figure 11] FIG. 11 is a plan view showing a protection element in which a soluble conductor for current interruption is provided with slits located between the first support electrode and the first electrode and between the second support electrode and the second electrode. [Figure 12] Figure 12 is a plan view showing a protection element in which the length L1 of the current-interrupting soluble conductor in the width direction perpendicular to the current flow direction is the same as the length L2 of the heat-interrupting soluble conductor in the width direction perpendicular to the current flow direction. [Figure 13] FIG. 13 is a plan view showing a protection element in which the widthwise length L1 of the current interruption soluble conductor is longer than the widthwise length L2 of the heat generation interruption soluble conductor. [Figure 14] Figure 14 shows a protective element according to a modified example, where (A) is a plan view, (B) is a cross-sectional view taken along the line DD' shown in (A), and (C) is a plan view showing the protective element without the cap member. [Figure 15] Figure 15 is a diagram showing the insulating substrate 2 for the protection element shown in Figure 14, where (A) shows the surface 2a side to which the heat-generating cut-off fusible conductor is connected, and (B) shows the back side opposite the surface. [Figure 16] Figure 16 is a diagram showing a configuration in which the second heating element electrode on the back side and the second heating element electrode on the front side are connected via a castellation formed on the side edge of the insulating substrate in the protective element shown in Figure 14, where (A) shows the front side to which the fusible conductor for heat interruption is connected, and (B) shows the back side opposite the front side. [Figure 17] 17A and 17B are diagrams showing a protection element according to a modified example, where (A) is a plan view and (B) is a DD' cross-sectional view of (A). [Figure 18]FIG. 18 is a plan view showing the protective element shown in FIG. 17 with the upper case thereof omitted, illustrating the step of mounting a fusible member on the upper surface of the heat generation cutoff fusible conductor. [Figure 19] FIG. 19 is a diagram showing a fusing member, where (A) is a plan view showing the front side of an insulating substrate connected to a heat generation interruption fusible conductor, and (B) is a bottom view showing the back side of the insulating substrate. [Figure 20] FIG. 20 is a circuit diagram of the protection element shown in FIG. [Figure 21] 21 is a cross-sectional view showing a state in which the heat generation cutoff fusible conductor of the protection element shown in FIG. 17 is melted. [Figure 22] 22 is a cross-sectional view showing a state in which one of the current interrupting fusible conductors of the protection element shown in FIG. 17 is melted. [Figure 23] 23 is a cross-sectional view showing a state in which both current interrupting fusible conductors of the protection element shown in FIG. 17 are melted. [Figure 24] Figure 24 shows a protective element in which a fusible conductor for heat generation interruption is connected to one side and the other side thereof with a fusible element having a heating element formed on the surface of an insulating substrate, where (A) is a plan view and (B) is a cross-sectional view taken along the line D-D' of (A). [Figure 25] Figure 25 shows the fusion member of the protection element shown in Figure 24, where (A) is a plan view showing the front side of the insulating substrate connected to the heat-generating fusible conductor, and (B) is a bottom view showing the back side of the insulating substrate. [Figure 26] 26A and 26B are diagrams showing a surface-mount type protection element, in which (A) is a plan view, (B) is a plan view showing the element without the cap member, and (C) is a cross-sectional view taken along the line DD' of (A). [Figure 27] Figure 27 shows the state in which the heat generation cut-off fusible conductor has melted in the protection element shown in Figure 26, where (A) is a plan view showing the state without the cap member, (B) is a cross-sectional view showing the state without the cap member, and (C) is a circuit diagram. [Figure 28] Figure 28 is a diagram showing a state in which one of the current-interrupting fusible conductors in the protection element shown in Figure 26 has melted, where (A) is a plan view showing the state without the cap member, and (B) is a circuit diagram. [Figure 29]29A and 29B are diagrams showing the state in which both current-interrupting fusible conductors in the protection element shown in FIG. 26 are melted, where (A) is a plan view showing the state in which the cap member is omitted, and (B) is a circuit diagram. [Figure 30] Figure 30 is a plan view showing a configuration in which multiple current-blocking soluble conductors are provided between the first support electrode and the first electrode and between the second support electrode and the second electrode in the protective element shown in Figure 26, with the cap member omitted. [Figure 31] Figure 31 is a diagram showing a configuration in which the current-interrupting soluble conductor in the protective element shown in Figure 26 has slits located between the first support electrode and the first electrode and between the second support electrode and the second electrode, with the cap member omitted, where (A) shows a configuration in which an approximately triangular slit is provided, and (B) shows a configuration in which an approximately arc-shaped slit is provided. [Figure 32] Figure 32 is a diagram showing a configuration in which the protective element shown in Figure 26 has through holes located between the first support electrode and the first electrode and between the second support electrode and the second electrode in the current interrupting soluble conductor, with the cap member omitted, where (A) shows a configuration in which multiple through holes are arranged in a single row, (B) shows a configuration in which multiple through holes are arranged in multiple rows, and (C) shows a configuration in which one relatively large through hole and multiple relatively small through holes are arranged. [Figure 33] FIG. 33 is a cross-sectional view showing a modified example of a surface-mount type protection element. [Figure 34] 34(A) is a plan view showing the protective element shown in FIG. 33 with the cap member omitted, and FIG. 34(B) is a bottom view of the protective element shown in FIG. [Figure 35] FIG. 35 shows an example of a conventional protection element for high voltages, where (A) is a plan view, (B) is a D-D' cross-sectional view of (A), (C) is a P-P' cross-sectional view of (A), and (D) is a plan view of (A) with the upper case omitted. [Figure 36] Figure 36 is a plan view of the protection element shown in Figure 35 with the upper case omitted, where (A) shows a schematic diagram of the state where shutdown has occurred due to self-heating caused by an overcurrent, and (B) and (C) show a schematic diagram of the state after shutdown. DETAILED DESCRIPTION OF THE INVENTION

[0020] A protection element and a battery pack to which the present technology is applied will be described in detail below with reference to the drawings. It should be noted that the present technology is not limited to the following embodiments, and various modifications are possible within the scope of the present technology. The drawings are schematic, and the ratios of the dimensions may differ from the actual dimensions. Specific dimensions should be determined with reference to the following description. It should be noted that the drawings may also include portions in which the dimensional relationships and ratios differ.

[0021] 1 shows a protection element 1 to which the present technology is applied, where (A) is a plan view, (B) is a plan view showing the protection element 1 without the upper case, and (C) is a cross-sectional view taken along the line D-D' of (A). As shown in Fig. 1, the protection element 1 includes an insulating substrate 2, a heating element 5 provided on the insulating substrate 2, a first electrode 3 and a second electrode 4, a heating element lead electrode 6 electrically connected to the heating element 5 on a current path between the first electrode 3 and the second electrode 4, a first support electrode 7 provided on the insulating substrate 2 and between the first electrode 3 and the heating element lead electrode 6, and a second support electrode 8 provided between the second electrode 4 and the heating element lead electrode 6, and a heat generating element 5 connected across the first support electrode 7, the heating element lead electrode 6, and the second support electrode 8. and a current interruption soluble conductor 11 which is connected between the first supporting electrode 7 and the first electrode 3 and between the second supporting electrode 8 and the second electrode 4 and which melts at least between the first electrode 3 and the first supporting electrode 7 or between the second electrode 4 and the second supporting electrode 8 due to self-heating caused by the passage of an overcurrent exceeding the rated value, thereby interrupting the current path.

[0022] The heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11 are connected in series. Therefore, when either soluble conductor is melted, the current path between the first electrode 3 and the second electrode 4 is interrupted.

[0023] In the protective element 1, the resistance value of the current interruption soluble conductor 11 is higher than the resistance value of the heat generation interruption soluble conductor 10. This can be achieved, for example, by configuring the constituent metal of the current interruption soluble conductor 11 with a metal (for example, Cu or an alloy mainly composed of Cu) having a lower resistance than the constituent metal of the heat generation interruption soluble conductor 10 (for example, SnAgCu alloy), and by making the cross-sectional area through which current flows of the current interruption soluble conductor 11 smaller than the cross-sectional area of ​​the heat generation interruption soluble conductor 10, and by making the length through which current flows of the current interruption soluble conductor 11 longer than the length of the heat generation interruption soluble conductor 10.

[0024] As a result, the heat interruption soluble conductor 10, which is electrically and thermally connected to the heating element 5, functions as a fuse element for heat interruption that melts before the current interruption soluble conductor 11 when heat is generated by the heating element 5. In addition, the current interruption soluble conductor 11, which has a higher resistance than the heat interruption soluble conductor 10, functions as a fuse element for current interruption that melts before the heat interruption soluble conductor 10 due to self-heating during an overcurrent.

[0025] Thus, the protective element 1 to which the present technology is applied includes a heat-interrupting soluble conductor 10 that melts and interrupts the current path due to heat generated by the heating element 5, and a current-interrupting soluble conductor 11 that melts and interrupts the current path due to self-heating caused by the passage of an overcurrent exceeding the rated voltage. This separates the functions of the soluble conductors. To make the resistance of the current-interrupting soluble conductor 11 higher than the resistance of the heat-interrupting soluble conductor 10, for example, the cross-sectional area through which current flows in the current-interrupting soluble conductor 11 is made smaller than the cross-sectional area of ​​the heat-interrupting soluble conductor 10. In other words, the volume of the current-interrupting soluble conductor 11 is reduced while increasing the current capacity. Therefore, because the volume of the current-interrupting soluble conductor 11 can be reduced, the occurrence of sparks and tracking after overcurrent interruption can be suppressed even when the rated voltage is increased.

[0026] Each component of the protection device 1 will be described in detail below.

[0027] [case] As shown in FIG. 1, the protection element 1 has a case 12, which houses various components and from which the first and second electrodes 3 and 4 and the heating element power supply electrode 15 (described later) are led out. The case 12 can be formed using insulating materials such as various engineering plastics, thermoplastic plastics, ceramics, and glass epoxy boards. The case 12 supports the first and second electrodes 3 and 4 and the heating element power supply electrode 15, leading them out from inside to outside the case. The case 12 also has sufficient internal space to allow the molten conductor 10 for heat interruption to expand spherically when it melts and to aggregate on the heating element lead electrode 6 and the first and second support electrodes 7 and 8.

[0028] The case 12 is formed by combining an upper case 21 and a lower case 22. Figure 2 shows the upper case 21 and the lower case 22, with (A) being a bottom view of the upper case 21, (B) being a plan view of the lower case 22, and (C) being a cross-sectional view showing the upper case 21 and the lower case 22 butted together. The upper case 21 has a mating recess 23 formed on the lower surface of its side wall. The lower case 22 has a mating protrusion 24 formed on the upper surface of its side wall that fits into the mating recess 23. The upper and lower cases 21, 22 are combined by fitting the mating protrusion 24 into the mating recess 23, and are fixed together with adhesive provided on the upper and lower surfaces of the side walls.

[0029] As shown in FIG. 2(B), the lower case 22 is formed in a substantially rectangular shape and includes a side edge 22a that has a fitting protrusion 24 and supports the first and second electrodes 3 and 4 and the heating element power supply electrode 15 (described later). The side edge 22a is a region surrounded by the side edge 22a and includes a hollow portion 22b in which the insulating substrate 2 connected to the heat interruption fusible conductor 10 is located. The side edge 22a extends around the entire inner surface of the lower case 22, where the first and second electrodes 3 and 4 and the heating element power supply electrode 15 are placed, supporting them both inside and outside the case 12. As shown in FIG. 1(B), the heating element power supply electrode 15 is supported so that each tip surface is flush with the inner end of the side edge 22a. The hollow portion 22b houses the insulating substrate 2 and has an internal space below the insulating substrate 2. Support columns 25 erected from the bottom of the hollow portion 22b can hold the insulating substrate 2 in place.

[0030] 2(A), the upper case 21 is formed in a substantially rectangular shape similar to the lower case 22, and is butt-joined to the lower case 22. The upper case 21 also has an internal space above the heat generation interruption fusible conductor 10 where the molten conductor 10a can wet, spread, and aggregate on the first and second support electrodes 7 and 8 and the heating element lead electrode 6.

[0031] [Insulating substrate] The insulating substrate 2 is formed of an insulating material such as alumina, glass ceramics, mullite, or zirconia. Alternatively, the insulating substrate 2 may be made of a material used for printed wiring boards, such as a glass epoxy board or a phenol board. A heating element lead electrode 6 connected to the heat interrupting fusible conductor 10 is formed on the surface 2a of the insulating substrate 2.

[0032] Furthermore, the insulating substrate 2 has a heat generation cutoff soluble conductor 10 physically connected to the heating element extraction electrode 6 formed on the surface 2a via a conductive connecting material such as connection solder 13. In the insulating substrate 2 according to the present technology, the surface on which the heating element extraction electrode 6 connected to the heat generation cutoff soluble conductor 10 is formed is referred to as the surface 2a, and the surface opposite to the surface 2a is referred to as the back surface 2b.

[0033] [First and second electrodes] The first and second electrodes 3, 4 can be formed using known terminal materials such as pure copper, copper alloys, etc. The first and second electrodes 3, 4 are, for example, rectangular plate-shaped, spaced apart in the current-carrying direction of the heat-interrupting soluble conductor 10 and the current-interrupting soluble conductor 11, supported by the side edge 22a of the lower case 22, and led out from inside the case 12 to the outside.

[0034] The first and second electrodes 3, 4 are each connected to an end of the current interruption soluble conductor 11 by a conductive bonding material such as connection solder 13. The first and second electrodes 3, 4 have screw holes 14 at their tips that extend outside the case 12, allowing them to be connected to connection electrodes provided in an external circuit by screwing or the like. By connecting the first and second electrodes 3, 4 to the connection electrodes, the heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11 are incorporated into part of the current path formed in the external circuit. Note that the first and second electrodes 3, 4 may not have screw holes 14 and may be connected to the connection electrodes using connection solder or the like.

[0035] The first and second electrodes 3, 4 are electrically connected via the heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11. In addition, the connection is interrupted by the heat generation interruption soluble conductor 10 and / or the current interruption soluble conductor 11 being melted.

[0036] [Heater element power supply electrode] Like the first and second electrodes, the heating element power supply electrode 15 can be formed using a known terminal material such as pure copper, a copper alloy, etc. The heating element power supply electrode 15 has, for example, a rectangular plate shape, is supported on the side edge 22a of the lower case 22, and is led out from a side of the case 12 different from the side from which the first and second electrodes are led out.

[0037] The heating element power supply electrode 15 is connected to a first heating element electrode 17 (described later) by a conductive bonding material such as connection solder 13. The heating element power supply electrode 15 has a screw hole 14 at its tip that extends outside the case 12, so that it can be connected to a connection electrode provided on an external circuit by screwing or the like. By connecting the heating element power supply electrode 15 to the connection electrode, the heating element 5 is connected to a heating element power supply path formed in the external circuit. Note that the heating element power supply electrode 15 may not have the screw hole 14 and may be connected to the connection electrode using connection solder or the like.

[0038] It is preferable that the power supply path to the heating element is interrupted by the melting of the heat-interrupting soluble conductor 10 and / or the current-interrupting soluble conductor 11, but the current may also be turned off by controlling a switch in response to detection of the melting of the heat-interrupting soluble conductor 10 and / or the current-interrupting soluble conductor 11.

[0039] [Heater] The protection element to which the present technology is applied includes an insulating substrate 2, a heating element 5 that melts a heat-blocking fusible conductor 10 by generating heat, and an insulating layer 16 that covers the heating element 5. In the protection element 1 shown in FIG. 1, the heating element 5 and the insulating layer 16 are provided on a surface 2a of the insulating substrate 2.

[0040] The heating element 5 is a conductive material with a relatively high resistance that generates heat when current is applied, and is made of, for example, nichrome, W, Mo, Ru, or a material containing these. The heating element 5 can be formed by mixing a powder of these alloys, compositions, or compounds with a resin binder or the like to form a paste, forming a pattern on the insulating substrate 2 using a screen printing technique, and firing the paste. For example, the heating element 5 can be formed by adjusting a mixed paste of ruthenium oxide paste, silver, and glass paste according to a predetermined voltage, forming a film of a predetermined area at a predetermined position on the surface 2a of the insulating substrate 2, and then firing the film under appropriate conditions. The shape of the heating element 5 can be designed as desired, but a roughly rectangular shape corresponding to the shape of the insulating substrate 2, as shown in Figure 1, is preferred to maximize the heating area.

[0041] The heating element 5 has one end connected to a first heating electrode 17 and the other end connected to a second heating electrode 18. The first heating electrode 17 is formed on one side edge of the surface 2a of the insulating substrate 2. The second heating electrode 18 is formed on the other side edge of the surface 2a of the insulating substrate 2, opposite to the one side edge. In the protection element 1 shown in FIG. 1, the first heating electrode 17 is superimposed on one end of the heating element 5, which is formed in a substantially rectangular shape. Similarly, the second heating electrode 18 is superimposed on the other end of the heating element 5, which is formed in a substantially rectangular shape.

[0042] The first heating element electrode 17 is connected to a heating element power supply electrode 15, which is connected to an external circuit via connection solder 13, and is thereby connected to a power source provided in the external circuit, enabling power to be supplied to the heating element 5. The second heating element electrode 18 is connected to the heating element lead electrode 6. As a result, the heating element lead electrode 6 is connected to the heating element 5 via the second heating element electrode 18. In the protection element 1 shown in FIG. 1, the first and second heating element electrodes 17, 18 are formed on opposite side edges of an insulating substrate 2 which is formed in a substantially rectangular shape.

[0043] The first and second heating electrodes 17, 18 can be formed by printing and firing a conductive paste such as Ag or Cu. Preferably, the surfaces of the first and second heating electrodes 17, 18 are coated with a film such as Ni / Au plating, Ni / Pd plating, or Ni / Pd / Au plating by a known method such as plating. This allows the protection element 1 to prevent oxidation of the first and second heating electrodes 17, 18 and prevent fluctuations in rating due to an increase in conduction resistance.

[0044] [Insulating layer] The heating element 5, the first heating element electrode 17, and the second heating element electrode 18 are covered with an insulating layer 16. On the insulating layer 16, a heating element lead electrode 6 is formed.

[0045] The insulating layer 16 is intended to protect and insulate the heating element 5. The insulating layer 16 is formed to be thin, for example, 10 to 40 μm in thickness, in order to efficiently transfer heat from the heating element 5 to the heating element lead electrode 6 and the heat generation cut-off soluble conductor 10. The insulating layer 16 can be formed, for example, by applying and baking a glass-based paste. The insulating layer 16 may also be formed between the surface 2 a of the insulating substrate 2 and the heating element 5.

[0046] [Heater element extraction electrode] The heating element lead electrode 6 is an electrode provided from the second heating element electrode 18 onto the insulating layer 16. The heating element lead electrode 6 is formed of a conductive pattern of Ag, Cu, or the like. The heating element lead electrode 6 can be formed by printing and firing a conductive paste using a screen printing technique or the like. In addition, it is preferable that the surface of the heating element lead electrode 6 is coated with a film such as Ni / Au plating, Ni / Pd plating, or Ni / Pd / Au plating by a known method such as plating.

[0047] One end of the heating element lead electrode 6 is connected to the other end of the heating element 5 via the second heating element electrode 18. The heating element lead electrode 6 extends on the insulating layer 16 in the region between the first support electrode 7 and the second support electrode 8, and is superimposed on the heating element 5 via the insulating layer 16. The heating element lead electrode 6 is connected to a heat interrupting fusible conductor 10 via a joining material such as connection solder 13.

[0048] [Support electrode] A first support electrode 7 and a second support electrode 8 are provided on the surface 2a of the insulating substrate 2. The first support electrode 7 and the second support electrode 8, together with the heating element lead electrode 6, support the heat generation interruption soluble conductor 10 with a bonding material such as connection solder 13 and hold the molten conductor 10a. The first support electrode 7, together with the first electrode 3, supports the current interruption soluble conductor 11 with a bonding material such as connection solder 13. The second support electrode 8, together with the second electrode 4, supports the current interruption soluble conductor 11 with a bonding material such as connection solder 13. The first support electrode 7 and the second support electrode 8 are formed on both side edges of the insulating substrate 2 in the extension direction of the heat generation interruption soluble conductor 10, sandwiching the heating element lead electrode 6. In the protection element 1 shown in FIG. 1, the first and second support electrodes 7 and 8 are formed on side edges of the insulating substrate 2, which are formed in a substantially rectangular shape, perpendicular to the side edges on which the first and second heating element electrodes 17 and 18 are formed.

[0049] The first support electrode 7 and the second support electrode 8 can be formed by printing and firing a conductive paste of Ag, Cu, or the like. Preferably, the surfaces of the first and second support electrodes 7, 8 are coated with a film such as Ni / Au plating, Ni / Pd plating, or Ni / Pd / Au plating by a known method such as plating. This prevents oxidation of the first and second support electrodes 7, 8 in the protective element 1, and can prevent fluctuations in rating due to an increase in conduction resistance.

[0050] [Fusible conductor] The heat interruption fusible conductor 10 is mounted between the first support electrode 7, via the heating element lead electrode 6, and the second support electrode 8, and melts when heated by the passage of current through the heating element 5, thereby interrupting the current path between the first electrode 3 and the second electrode 4. The heat interruption fusible conductor 10 may be any conductive material that melts when heated by the passage of current through the heating element 5, and may be, for example, a single metal such as Sn, or a SnAgCu-based Pb-free solder, a BiPbSn alloy, a BiPb alloy, a BiSn alloy, a SnPb alloy, a PbIn alloy, a ZnAl alloy, an InSn alloy, a PbAgSn alloy, or the like.

[0051] Furthermore, the heat generation blocking soluble conductor 10 may be a structure containing a high melting point metal and a low melting point metal. Figure 3 is a perspective view showing an example of the configuration of the heat generation blocking soluble conductor 10, where (A) shows a heat generation blocking soluble conductor 10A having a laminated structure, and (B) and (C) show heat generation blocking soluble conductors 10B having a coated structure. In this specification, when there is no need to distinguish between the heat generation blocking soluble conductor 10A having a laminated structure and the heat generation blocking soluble conductor 10B having a coated structure, they will simply be referred to as "heat generation blocking soluble conductor 10."

[0052] The heat interrupting soluble conductor 10A is a laminated structure consisting of an upper layer and a lower layer, as shown in FIG. 3(A), for example, and has a high melting point metal layer 26 as the upper layer and a low melting point metal layer 27 as the lower layer connected to the heating element lead electrode 6, and in the protective element 1, for example, it has a rectangular plate shape in a plan view. The heat interrupting soluble conductor 10A is formed by heating a laminate formed by stacking the high melting point metal layer 26 and the low melting point metal layer 27 by reflow or the like. The high melting point metal layer 26 and the low melting point metal layer 27 of the laminate constituting the heat interrupting soluble conductor 10A can be stacked by known stacking methods such as rolling, crimping, plating coating, etc.

[0053] The heat interruption soluble conductor 10B is a coated structure in which both sides of a low-melting-point metal layer 27 are coated with a high-melting-point metal layer 26, as shown in FIG. 3(B), for example. It may have a rectangular plate shape in plan view, or a round wire shape as shown in FIG. 3(C). The heat interruption soluble conductor 10B is formed by heating a laminate having a coated structure in which at least both the upper and lower sides of the low-melting-point metal layer 27 constituting the inner layer are coated with a high-melting-point metal layer 26 constituting the outer layer, by reflow or the like. The laminate constituting the heat interruption soluble conductor 10B can be formed, for example, by plating a low-melting-point metal foil with a high-melting-point metal. This laminate may also be formed by plating a long low-melting-point metal foil with a high-melting-point metal and then cutting it to a predetermined length, so that both ends of the cut surface are exposed and the periphery is coated with the high-melting-point metal layer 26. The high-melting-point metal layer may be formed by plating or by known lamination or film formation techniques.

[0054] In addition, the heat generation cut-off soluble conductor 10B may have a coating structure with the high melting point metal layer 26 as the inner layer and the low melting point metal layer 27 as the outer layer. The heat generation cut-off soluble conductor 10A may have a two-layer structure in which the lower layer connected to the heating element lead electrode 6 is the high melting point metal layer 26 and the upper layer is the low melting point metal layer 27, or a multilayer structure of three or more layers in which the high melting point metal layer 26 and the low melting point metal layer 27 are alternately stacked, or a structure in which an opening is provided in part of the outer layer to expose part of the inner layer. It can be formed in various configurations.

[0055] The high-melting-point metal layer 26 and the low-melting-point metal layer 27 are made of metals that have a difference in melting point and can melt, with the metal layer with a relatively low melting point being the "low-melting-point metal layer" and the metal layer with a relatively high melting point being the "high-melting-point metal layer." The high-melting-point metal layer 26 and the low-melting-point metal layer 27 may be metal layers made of a single metal, or may be alloy layers made of two or more metals. While unintended metals may be contained as impurities in addition to the metals that make up each metal layer, these impurities are not considered to be constituent metals.

[0056] The high-melting-point metal constituting the high-melting-point metal layer 26 is, for example, Ag or Cu, or an alloy containing either of them as a main component. The high-melting-point metal layer 26 has a liquidus temperature of 400°C or higher, and has a high melting point that prevents it from melting even when the first and second support electrodes 7 and 8 and the heating element lead electrode 6 are connected to the heat generation cut-off fusible conductor 10 or when the protective element 1 is mounted on a circuit board by reflow.

[0057] The low-melting-point metal constituting the low-melting-point metal layer 27 is, for example, a solder or a metal containing Sn as a main component, a material generally called “Pb-free solder.” The liquidus temperature of the low-melting-point metal layer 27 does not necessarily have to be higher than the reflow temperature, and may be, for example, less than 260°C, and may melt at about 200°C.

[0058] The heat generation cutoff fusible conductor 10 is connected to the first and second support electrodes 7, 8 and the heating element extraction electrode 6 via a conductive connection medium 28 such as solder paste or a low-melting point metal layer 27 melted by heat such as reflow.

[0059] The heat generation cutoff soluble conductor 10 has a coating structure or laminated structure of the high melting point metal layer 26 and the low melting point metal layer 27, so that even if the reflow temperature exceeds the melting temperature of the low melting point metal layer 27, the shape of the heat generation cutoff soluble conductor 10 can be maintained and it will not melt. Therefore, the connection between the first and second support electrodes 7, 8 and the heating element lead electrode 6 and the heat generation cutoff soluble conductor 10 and the mounting of the protective element 1 on an external circuit board can be efficiently performed by reflow. In addition, even if the heat generation cutoff soluble conductor 10 is deformed by reflow, the resistance value becomes locally high or low. This can prevent fluctuations in the fusing characteristics, such as not melting at a predetermined temperature or melting at a temperature lower than the predetermined temperature.

[0060] In addition, by using a metal with low resistance such as Ag as the high-melting point metal layer 26, the soluble conductor 10 for heat generation interruption can suppress an increase in internal resistance and improve the rating while preventing the protective element 1 from becoming larger.

[0061] The heat-interrupting fusible conductor 10 can improve resistance (pulse resistance) to surges, which are instantaneous applications of abnormally high voltages to electrical systems incorporating the protective element 1. In other words, the heat-interrupting fusible conductor 10 must not melt even when, for example, a 100-A current flows for several milliseconds. Because large currents that flow in an extremely short time flow through the surface layer of the conductor (the skin effect), the heat-interrupting fusible conductor 10 has a low-resistance, high-melting-point metal layer 26, such as Ag, as its upper layer. This allows currents applied by surges to flow easily, preventing melting due to self-heating. Therefore, the heat-interrupting fusible conductor 10 can significantly improve surge resistance compared to fuses made of conventional solder alloys.

[0062] The heat generation interruption fusible conductor 10 is preferably coated with flux 29 to prevent oxidation and improve wettability during melting (see FIG. 1(C)).

[0063] When the heating element 5 is energized and generates heat, the low-melting-point metal layer 27, which melts first, corrodes (solder-eats) the high-melting-point metal layer 26, causing the high-melting-point metal layer 26 to melt at a temperature lower than its melting point. Therefore, the heat-generation interruption soluble conductor 10 can be blown out in a short time by utilizing the erosion of the high-melting-point metal layer 26 by the low-melting-point metal layer 27. In addition, the molten conductor 10a of the heat-generation interruption soluble conductor 10 is cut off by the physical pulling action of the heating element lead electrode 6 and the first and second support electrodes 7 and 8, so the current path between the first and second electrodes 3 and 4 can be quickly and reliably cut off (FIG. 4).

[0064] The configuration of the heat interruption soluble conductor 10 has been described above, but the current interruption soluble conductor 11 also has a similar configuration to the heat interruption soluble conductor 10. The current interruption soluble conductor 11 includes a first current interruption soluble conductor 11A mounted between the first support electrode 7 and the first electrode 3, and a second current interruption soluble conductor 11B mounted between the second support electrode 8 and the second electrode 4. The first and second current interruption soluble conductors 11A and 11B melt due to self-heating (Joule heat) when a current exceeding their rated current is passed through them, thereby interrupting the current path between the first electrode 3 and the second electrode 4. In this specification, when there is no need to distinguish between the first current interruption soluble conductor 11A and the second current interruption soluble conductor 11B, they are simply referred to as the "current interruption soluble conductor 11."

[0065] The current interrupting soluble conductor 11 is connected to the first and second support electrodes 7, 8 and the first and second electrodes 3, 4 via a conductive connecting material such as connecting solder 13 or a low-melting point metal layer 27 melted by heat such as reflow.

[0066] The current interrupting soluble conductor 11 will not melt even if it generates heat while a predetermined rated current is flowing. When a current higher than the rated current flows, it melts due to heat generation and interrupts the current path between the first and second electrodes 3 and 4.

[0067] 1(B), the protective element 1 has a heat generation interruption soluble conductor 10 and first and second current interruption soluble conductors 11A and 11B connected in series between the first electrode 3 and the second electrode 4. Therefore, even if any of the soluble conductors melts, the current path between the first electrode 3 and the second electrode 4 is interrupted.

[0068] [Resistance value] In the protective element 1, the resistance values ​​of the first and second current interruption soluble conductors 11A, 11B are made higher than the resistance value of the heat generation interruption soluble conductor 10. This can be achieved, for example, by configuring the constituent metal of the current interruption soluble conductor 11 with a metal (for example, Cu or an alloy mainly composed of Cu) having a lower resistance than the constituent metal of the heat generation interruption soluble conductor 10 (for example, a SnAgCu alloy), and by making the cross-sectional area through which current flows of the current interruption soluble conductor 11 smaller than the cross-sectional area of ​​the heat generation interruption soluble conductor 10, and by making the length through which current flows of the current interruption soluble conductor 11 longer than the length of the heat generation interruption soluble conductor 10.

[0069] Because the resistance values ​​of the first and second current interrupting soluble conductors 11A, 11B are relatively high, the amount of self-heating due to overcurrent also increases in the first and second current interrupting soluble conductors 11A, 11B, causing them to melt before the heat generation interrupting soluble conductor 10. The heat generation interrupting soluble conductor 10 is arranged overlapping the heating element 5 and is also thermally connected to the heating element 5 via the heating element lead electrode 6, so it melts before the first and second current interrupting soluble conductors 11A, 11B due to the heat generated by the heating element 5 being energized.

[0070] Thus, the protective element 1 to which the present technology is applied includes a heat-interrupting soluble conductor 10 that melts and interrupts the current path due to heat generated by the heating element 5, and first and second current interrupting soluble conductors 11A, 11B that melt and interrupt the current path due to self-heating caused by the passage of an overcurrent exceeding the rated current. This separates the functions of the soluble conductors. To make the resistance values ​​of the first and second current interrupting soluble conductors 11A, 11B higher than the resistance value of the heat-interrupting soluble conductor 10, for example, the cross-sectional area through which current flows in the current interrupting soluble conductor 11 is made smaller than the cross-sectional area of ​​the heat-interrupting soluble conductor 10. In other words, the volume of the current interrupting soluble conductor 11 is reduced while increasing the current capacity. Therefore, the volume of the current interrupting soluble conductor 11 can be reduced, reducing the amount of vapor scattering from the molten conductor of the current interrupting soluble conductor 11. This prevents soot-like material from forming within the case 12, preventing the formation of a conductive path. Therefore, the protective element 1 can suppress the occurrence of sparks and tracking phenomena after an overcurrent is interrupted even when the rated voltage is increased, and can maintain a high insulation resistance after the current is interrupted.

[0071] The resistance values ​​of the first and second current interruption soluble conductors 11A and 11B are preferably at least twice, and more preferably at least five times, the resistance value of the heat interruption soluble conductor 10. The resistance values ​​of the first current interruption soluble conductor 11A and the second current interruption soluble conductor 11B may be the same or different. By making the resistance values ​​of the first current interruption soluble conductor 11A and the second current interruption soluble conductor 11B different, the relatively high-resistance current interruption soluble conductor 11 can be preferentially melted during an overcurrent. [Circuit configuration example]

[0072] [Circuit configuration example] Such a protection device 1 is used by being incorporated into a circuit in a battery pack 30 of, for example, a lithium ion secondary battery. As shown in Fig. 5, the battery pack 30 has a battery stack 35 made up of, for example, a total of four battery cells 31a to 31d of lithium ion secondary batteries.

[0073] The battery pack 30 includes a battery stack 35, a charge / discharge control circuit 36 ​​that controls the charging and discharging of the battery stack 35, a protection element 1 to which the present invention is applied that cuts off the charge / discharge path when an abnormality occurs in the battery stack 35, a detection circuit 37 that detects the voltage of each battery cell 31a to 31d, and a current control element 38 that serves as a switch element that controls the operation of the protection element 1 in accordance with the detection result of the detection circuit 37.

[0074] The battery stack 35 is a series connection of battery cells 31a to 31d that require control to protect against overcharge and overdischarge, and is detachably connected to a charging device 32 via the positive terminal 30a and negative terminal 30b of the battery pack 30, and a charging voltage is applied from the charging device 32. The battery pack 30 charged by the charging device 32 can be used to operate an electronic device that runs on a battery by connecting the positive terminal 30a and negative terminal 30b to the electronic device.

[0075] The charge / discharge control circuit 36 ​​includes two current control elements 33a and 33b connected in series in a current path between the battery stack 35 and the charging device 32, and a control unit 34 that controls the operation of these current control elements 33a and 33b. The current control elements 33a and 33b are configured, for example, with field effect transistors (hereinafter referred to as FETs), and the control unit 34 controls the gate voltage to control the conduction and interruption of the current path of the battery stack 35 in the charging and / or discharging directions. Depending on the detection result by the detection circuit 37, the control unit 34 controls the operation of the current control elements 33a and 33b so as to interrupt the current path when the battery stack 35 is over-discharged or over-voltage (overcharged).

[0076] The protection element 1 is connected, for example, on a charge / discharge current path between a battery stack 35 and a charge / discharge control circuit 36, and its operation is controlled by a current control element .

[0077] The detection circuit 37 is connected to each of the battery cells 31a to 31d, detects the voltage value of each of the battery cells 31a to 31d, and supplies each voltage value to the control unit 34 of the charge / discharge control circuit 36. The detection circuit 37 also outputs a control signal for controlling the current control element 38 when any one of the battery cells 31a to 31d reaches an overcharge voltage or an overdischarge voltage.

[0078] The current control element 38 is configured, for example, by a FET, and when the detection signal output from the detection circuit 37 indicates that the voltage value of the battery cells 31a to 31d exceeds a predetermined over-discharge or over-charge state, it activates the protection element 1 and controls the charge / discharge current path of the battery stack 35 to be cut off regardless of the switch operation of the current control elements 33a and 33b.

[0079] The protective element 1 to which the present invention is applied and used in the battery pack 30 configured as described above has a circuit configuration as shown in FIG. 6. That is, the first electrode 3 of the protective element 1 is connected to the battery stack 35, and the second electrode 4 is connected to the positive terminal 30a, thereby connecting the heat-exchange interruption soluble conductor 10 and the current-interruption soluble conductor 11 in series to the charge / discharge path of the battery stack 35. Furthermore, the heating element 5 of the protective element 1 is connected to the current control element 38 via the heating element power supply electrode 15, and the heating element 5 is connected to one end of the battery stack 35. Thus, one end of the heating element 5 is connected to one end of the battery stack 35 via the heating element lead electrode 6, the heat-exchange interruption soluble conductor 10, the current-interruption soluble conductor 11, and the first electrode 3, and the other end is connected to the current control element 38 and the other end of the battery stack 35 via the heating element power supply electrode 15. This forms a power supply path to the heating element 5, the current supply of which can be controlled by the current control element 38.

[0080] [Protection element operation] 4A, 4B, and 4C are diagrams showing the state in which the heat-exchange cutoff soluble conductor 10 melts in the protection element 1 shown in FIG. 1, with the case 12 omitted. (A) is a plan view, (B) is a cross-sectional view, and (C) is a circuit diagram. When the detection circuit 37 detects an abnormal voltage in any of the battery cells 31a to 31d, it outputs a cutoff signal to the current control element 38. The current control element 38 then controls the current to energize the heating element 5. In the protection element 1, current flows from the battery stack 35 to the heating element 5, causing the heating element 5 to begin generating heat. In the protection element 1, heat from the heating element 5 is transferred to the heat-exchange cutoff soluble conductor 10 via the second heating element electrode 18 and the heating element lead electrode 6, which have excellent thermal conductivity, and through the insulating layer 16, causing the heat-exchange cutoff soluble conductor 10 to melt (FIG. 4). This interrupts the current path between the first and second electrodes 3 and 4, and cuts off the charge / discharge path of the battery stack 35. The protective element 1 forms the heat-blocking soluble conductor 10 in a laminated or coated structure of a high-melting point metal layer 26 and a low-melting point metal layer 27, so that the low-melting point metal layer 27 melts before the high-melting point metal layer 26 melts, and the melting action of the molten low-melting point metal layer 27 on the high-melting point metal layer 26 can be utilized to melt the heat-blocking soluble conductor 10 in a short time.

[0081] When the heat generation cutoff fusible conductor 10 of the protection element 1 melts, the power supply path to the heating element 5 is also cut off, and therefore the heating element 5 stops generating heat.

[0082] Furthermore, when an overcurrent exceeding the rated current flows through the battery pack 30, the current interruption soluble conductor 11 melts due to self-heating. In the protection element 1, one (FIG. 7) or both (FIG. 8) of the first current interruption soluble conductor 11A and the second current interruption soluble conductor 11B melts. This cuts off the current path between the first and second electrodes 3 and 4, and cuts off the charge / discharge path of the battery stack 35.

[0083] When the first current interruption soluble conductor 11A and / or the second current interruption soluble conductor 11B melts, the power supply path to the heating element 5 is also cut off, and heat generation by the heating element 5 is stopped. As described above, the protection element 1 is configured as a fuse element for interrupting overcurrent by making the current interruption soluble conductor 11 small and relatively high-resistance, so the amount of vapor scattering of the molten conductor of the current interruption soluble conductor 11 is reduced, soot-like material does not continue within the case 12, and it is possible to prevent the formation of a conductive path.

[0084] The protection device 1 according to the present invention is not limited to use in a battery pack for lithium ion secondary batteries, and can of course be applied to various uses that require the interruption of a current path by an electrical signal.

[0085] [Modification of fusible conductor for current interruption] 9, the protection element 1 may have a plurality of current-blocking soluble conductors 11 between the first support electrode 7 and the first electrode 3, and between the second support electrode 8 and the second electrode 4. This makes it possible to reduce the size and increase the resistance of each current-blocking soluble conductor 11, and to increase the current capacity between the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4.

[0086] 10, the protective element 1 may have through holes 41 located between the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4 in the current interrupting soluble conductor 11. As shown in FIG. 10, only one through hole 41 may be provided, or multiple through holes 41 may be provided. For example, multiple through holes 41 may be provided in a direction perpendicular to the current flow direction of the current interrupting soluble conductor 11. By narrowing the periphery of the through hole 41, the current interrupting soluble conductor 11 has high resistance and the melting portion is limited, which reduces the amount of vapor scattering from the molten conductor when it melts due to an overcurrent.

[0087] 11, the protective element 1 may have slits 42 located between the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4 in the current interrupting soluble conductor 11. The slits 42 are preferably provided in a direction perpendicular to the current flow direction of the current interrupting soluble conductor 11. As shown in FIG. 11, the slits 42 are preferably provided on both side surfaces of the current interrupting soluble conductor 11. By narrowing the area around the slits 42, the current interrupting soluble conductor 11 has a high resistance and the melting portion is limited, which reduces the amount of vapor scattering from the molten conductor when it melts due to an overcurrent.

[0088] 12, the protection element 1 may have the width direction length L1 of the current interrupting soluble conductor 11 perpendicular to the current flow direction equal to the width direction length L2 of the heat interrupting soluble conductor 10 perpendicular to the current flow direction, or as shown in FIG. 13, the width direction length L1 may be longer than the width direction length L2 of the heat interrupting soluble conductor 10. Even if the width direction length L1 of the current interrupting soluble conductor 11 is equal to or greater than the width direction length L2 of the heat interrupting soluble conductor 10, the resistance value can be made higher than the resistance value of the heat interrupting soluble conductor by adjusting the length in the current flow direction, thickness, etc.

[0089] In the protective element 1, the first current interruption soluble conductor 11A and the second current interruption soluble conductor 11B are provided as the current interruption soluble conductor 11, but only one of them may be provided. For example, only the first current interruption soluble conductor 11A may be provided, and the heat generation interruption soluble conductor 10 may be connected between the heating element lead electrode 6 and the fourth electrode 4.

[0090] [Variation 1: Backside heater structure] Next, modified examples of the protection element to which the present technology is applied will be described. In the protection element to which the present technology is applied, the heating element 5 may be provided on the rear surface 2b of the insulating substrate 2. In the protection element 50 shown in Fig. 14, the heating element 5 and the insulating layer 16 covering it are provided on the rear surface 2b of the insulating substrate 2. In the following description, the same components as those in the protection element 1 described above will be assigned the same reference numerals, and details thereof will be omitted.

[0091] 14 is a diagram showing a protection element 50 according to a modified example, (A) is a plan view, (B) is a cross-sectional view taken along the line D-D' in (A), and (C) is a plan view showing the cap member omitted. Fig. 15 is a diagram showing an insulating substrate 2 according to the protection element 50, (A) shows the surface 2a side to which the heat generation cutoff fusible conductor 10 is connected, and (B) shows the back surface 2b side opposite to the surface 2a.

[0092] In the protection element 50 according to the modified example, first heating element electrodes 17 are formed on the front surface 2a and rear surface 2b of the insulating substrate 2 and connected via conductive through holes 51. Similarly, second heating element electrodes 18 are formed on the front surface 2a and rear surface 2b of the insulating substrate 2 and connected via conductive through holes 52.

[0093] 15(A), a first support electrode 7, a second support electrode 8, a surface-side first heating element electrode 17a, a surface-side second heating element electrode 18a, and a heating element lead electrode 6 are formed on a surface 2a of an insulating substrate 2. The heating element lead electrode 6 is connected to the surface-side second heating element electrode 18a.

[0094] 15(B), the heating element 5, the insulating layer 16, the rear surface-side first heating element electrode 17b, and the rear surface-side second heating element electrode 18b are formed on the rear surface 2b of the insulating substrate 2. One end of the heating element 5 is connected to the rear surface-side first heating element electrode 17b, and the other end is connected to the rear surface-side second heating element electrode 18b.

[0095] The front-side first heating element electrode 17a and the back-side first heating element electrode 17b are connected via a conductive through-hole 51. The front-side first heating element electrode 17a is connected to a heating element power supply electrode 15 connected to an external circuit via connection solder 13. This connects the heating element 5 to a power source provided in the external circuit, enabling power to be supplied. The conductive through-hole 51 may be formed as a castellation formed on the side edge of the insulating substrate, or as a through-hole.

[0096] The front-side second heating element electrode 18a and the back-side second heating element electrode 18b are formed on the same edge of the insulating substrate 2 and connected via conductive through-holes 52. As a result, the heating element lead electrode 6 is electrically and thermally connected to the heating element 5 via the front-side second heating element electrode 18a and the back-side second heating element electrode 18b. In the protective element 50, the heating element 5 heats the heating element lead electrode 6 via the insulating substrate 2, and heat from the heating element 5 is transferred to the heating element lead electrode 6 via the back-side second heating element electrode 18b and the front-side second heating element electrode 18a, which have excellent thermal conductivity, thereby heating and fusing the heat interruption fusible conductor 10. The conductive through-holes 52 may be formed as through-holes as shown in FIG. 15 or as castellations formed on the side edges of the insulating substrate as shown in FIG. 16.

[0097] [Variation 2: Backside heater clamping structure] Next, we will explain other modified examples of the protection element to which the present technology is applied. Figure 17 shows a protection element 60 according to a modified example, where (A) is a plan view and (B) is a cross-sectional view taken along the line D-D' of (A). Figure 18 is a plan view of the protection element 60 omitting the upper case 21, showing the process of mounting a fusing member 61 on the upper surface of the heat generation cutoff fusible conductor 10. The protective element 60 comprises an insulating substrate 2, a heating element 5, a heating element extraction electrode 6, and first and second support electrodes 7, 8, and forms a fusing member 61 that fuses the heat-blocking fusible conductor 10, and the heat-blocking fusible conductor 10 is clamped between the multiple fusing members 61.

[0098] 19 is a diagram showing a fusing member 61, where (A) is a plan view showing the front surface 2a side of the insulating substrate 2 connected to the heat generation interruption fusible conductor 10, and (B) is a bottom view showing the back surface 2b side of the insulating substrate 2. The fusing member 61 has an insulating substrate 2, and on the front surface 2a of the insulating substrate 2, a first support electrode 7, a second support electrode 8, a front surface side first heating element electrode 17a, and a heating element lead electrode 6 are formed. On the back surface 2b of the insulating substrate 2, a heating element 5, a back surface side first heating element electrode 17b, a second heating element electrode 18, an insulating layer 16, and a holding electrode 62 provided on the insulating layer 16 and holding the molten conductor 10a of the heat generation interruption fusible conductor 10 are formed.

[0099] The fusing member 61 has two heating elements 5 formed in parallel on the rear surface 2b of the insulating substrate 2. One end of each heating element 5 is connected to the first heating element electrode 17b on the rear surface side, and the other end is connected to the second heating element electrode 18. Note that the protective element 60 may have one heating element 5 or three or more heating elements 5.

[0100] The front-side first heating electrode 17a and the back-side first heating electrode 17b are formed on the same edge of the insulating substrate 2 and are connected via a castellation 65. The front-side first heating electrode 17a is connected to a heating element power supply electrode 15 that is connected to an external circuit via connection solder 13. This connects the heating element 5 to a power source provided in the external circuit and enables power to be supplied. The front-side first heating electrode 17a and the back-side first heating electrode 17b may be connected via a castellation 65 formed on the side edge of the insulating substrate, or via a through-hole with a conductive layer.

[0101] The heating element 5, the first heating element electrode 17b on the rear surface, and a portion of the second heating element electrode 18 are covered with an insulating layer 16. A holding electrode 62 is formed on the insulating layer 16. The holding electrode 62 is formed in a position opposite the heating element lead electrode 6 formed in the approximate center of the front surface 2a, with the insulating substrate 2 interposed therebetween. The holding electrode 62 is also connected to the second heating element electrode 18.

[0102] The holding electrode 62 is electrically and thermally connected to the heating element extraction electrode 6 via a conductive through-hole 63 that penetrates from the surface of the holding electrode 62 to the surface of the heating element extraction electrode 6, and is also physically continuous with the same. As a result, when the molten conductor 10a of the heat generation interruption fusible conductor 10 that has melted on the heating element extraction electrode 6 is attracted to the holding electrode 62 side via the conductive through-hole 63, it can be held on the holding electrode 62.

[0103] The holding electrodes 62 can be formed by a known method such as screen printing using a known electrode material such as Ag, Cu, or an alloy material containing Ag or Cu as a main component.

[0104] When the heat generation interruption fusible conductor 10 melts, the conductive through-hole 63 attracts the molten conductor 10a of the heat generation interruption fusible conductor 10 by capillary action, thereby reducing the volume of the molten conductor 10a held on the heating element lead-out electrode 6. As a result, even if the amount of melting increases due to the increase in size of the heat generation interruption fusible conductor 10 as a result of the higher rating and higher capacity of the protective element 60, a large amount of molten conductor 10a can be held by the holding electrode 62, the heating element lead-out electrode 6, and the first and second support electrodes 7 and 8, and the heat generation interruption fusible conductor 10 can be reliably melted.

[0105] The conductive through-holes 63 are formed in areas of the insulating substrate 2 where no heating elements 5 are formed. In the fusing member 61 shown in Figures 17, 18 and 19, the conductive through-holes 63 are formed in areas between the parallel heating elements 5.

[0106] A conductive layer 64 is formed on the inner surface of the conductive through-hole 63. The conductive layer 64 is continuous with the holding electrode 62 and the heating element lead electrode 6. This electrically connects the holding electrode 62 and the heating element lead electrode 6 via the conductive layer 64. Furthermore, by forming the conductive layer 64, heat from the heating element 5 is also conducted to the heating element lead electrode 6 via the holding electrode 62 and the conductive through-hole 63.

[0107] Furthermore, since the molten conductor 10a aggregates in the heating element extraction electrode 6 when it is blown, the continuity between the heating element extraction electrode 6 and the conductive layer 64 makes it easier to guide the molten conductor 10a into the conductive through-hole 63. The molten conductor 10a also spreads and is held by the holding electrode 62, which is continuous with the conductive layer 64. Therefore, more molten conductor 10a can be attracted and held by the conductive through-hole 63 and the holding electrode 62, reducing the volume of the molten conductor 10a held by the heating element extraction electrode 6 and the first and second support electrodes 7 and 8, and ensuring reliable blowing.

[0108] The conductive layer 64 is formed of, for example, any one of copper, silver, gold, iron, nickel, palladium, lead, and tin, or an alloy containing any one of these as a main component, and can be formed on the inner surface of the conductive through-hole 63 by a known method such as electrolytic plating or printing with a conductive paste. Alternatively, the conductive layer 64 may be formed by inserting a plurality of metal wires or an aggregate of conductive ribbons into the conductive through-hole 63.

[0109] The fusing member 61 may have a plurality of conductive through holes 63. This increases the number of paths for attracting the molten conductor 10a of the heat generation interruption fusible conductor 10, and quickly attracts more molten conductor 10a, thereby reducing the volume of the molten conductor 10a held by the heating element extraction electrode 6 and the first and second support electrodes 7 and 8.

[0110] [Step of forming the protective element 60] The process of forming the fusing member 61 for the protective element 60 begins with forming the first and second support electrodes 7 and 8, the heater lead electrode 6, and the front-side first heater electrode 17a on the front surface 2a of the insulating substrate 2, where the half-through holes for the castellations 65 are formed, using a known forming method such as screen printing. The rear-side first heater electrode 17b and the second heater electrode 18 are also formed on the rear surface 2b of the insulating substrate 2 using a known forming method such as screen printing, followed by forming the heater 5 and laminating the insulating layer 16. Next, a holding electrode 62 connecting to the second heater electrode 18 is formed on the insulating layer 16. After that, a through-hole is formed using a drill or the like, and a conductive layer 64 is formed by plating or the like, thereby forming the conductive through-hole 63. Furthermore, a castellation 65 is formed by plating or the like, connecting the front-side first heater electrode 17a and the rear-side first heater electrode 17b. This results in the fusing member 61.

[0111] The first fusing member 61 is supported in the hollow portion 22b of the case 12 by a support column 25. The first fusing member 61 is connected to the heating element lead electrode 6 and the first and second support electrodes 7, 8 and one surface of the heat interruption soluble conductor 10 via the connection solder 13. The first fusing member 61 is also connected to the first and second electrodes 3, 4 and the first and second support electrodes 7, 8 and the current interruption soluble conductor 11 via the connection solder 13. Furthermore, the first heating element electrode 17a on the front surface side of the insulating substrate 2 is connected to the heating element power supply electrode 15 supported on the side edge portion 22a of the lower case 22 by the connection solder 13.

[0112] Thereafter, the heating element lead electrode 6 and the first and second support electrodes 7, 8 of the other fusing member 61 are connected to the other surface of the heat interruption fusible conductor 10 via connection solder 13 (see FIG. 18). Also, the first heating element electrode 17a on the front surface side of the insulating substrate 2 is connected to the heating element power supply electrode 15 supported on the side edge portion 22a of the lower case 22 by connection solder 13. In addition, a support column 25 supporting the other fusing member 61 is erected on the top surface of the upper case 21 for the protection element 60, thereby making it possible to support the other fusing member 61 without swinging.

[0113] 20 is a circuit diagram of the protection element 60. Each fusing member 61 connected to the heat generation cutoff soluble conductor 10 has one end of each heating element 5 formed on the back surface 2b of the insulating substrate 2 connected to the heat generation cutoff soluble conductor 10 via a conductive through hole 63 and a heating element lead electrode 6. In addition, each fusing member 61 has a front surface-side first heating element electrode 17a connected to the other end of each heating element 5, which is connected to the heating element power supply electrode 15 via a connecting material such as connection solder 13. As a result, each fusing member 61 connects each heating element 5 to a power source provided in an external circuit via the heating element power supply electrode 15, allowing each heating element 5 to generate heat.

[0114] When each heating element 5 generates heat and the molten conductor 10a of the heat generation cutoff fusible conductor 10 aggregates on the heating element lead electrode 6, the protective element 60 guides the molten conductor 10a into the conductive through-hole 63, and causes the molten conductor 10a to wet and spread on the holding electrode 62 continuous with the conductive layer 64, and is held therein (see FIG. 21). Therefore, more molten conductor 10a can be attracted and held by the conductive through-hole 63 and the holding electrode 62, reducing the volume of the molten conductor 10a held by the heating element lead electrode 6 and the first and second support electrodes 7, 8, and ensuring melting.

[0115] 19, it is preferable that a plurality of conductive through holes 63 be formed in the protection element 60. This increases the number of paths for attracting the molten conductor 10a, and allows more molten conductor 10a to be attracted quickly, thereby reducing the volume of the molten conductor 10a held by the heating element extraction electrode 6 and the first and second support electrodes 7 and 8.

[0116] Furthermore, when the protective element 60 melts the heat-generation cutoff soluble conductor 10 due to heat generated by the heating element 5, the heating elements 5 of the fusing members 61 connected to both sides of the heat-generation cutoff soluble conductor 10 generate heat, heating both sides of the heat-generation cutoff soluble conductor 10. Therefore, even if the cross-sectional area of ​​the heat-generation cutoff soluble conductor 10 is increased to accommodate large current applications, the protective element 60 can quickly heat and melt the heat-generation cutoff soluble conductor 10.

[0117] Furthermore, the protective element 60 attracts the molten conductor 10a from both sides of the heat generation interruption soluble conductor 10 into each conductive through-hole 63 formed in each fusing member 61 and holds it with the holding electrode 62. Therefore, even when the cross-sectional area of ​​the heat generation interruption soluble conductor 10 is increased to accommodate large current applications and a large amount of molten conductor 10a is generated, the protective element 60 can attract the molten conductor 10a with the multiple fusing members 61 and reliably fuse the heat generation interruption soluble conductor 10. Furthermore, by attracting the molten conductor 10a with the multiple fusing members 61, the protective element 60 can fuse the heat generation interruption soluble conductor 10 more quickly.

[0118] The protective element 60 can quickly fuse the heat-cutoff fusible conductor 10, even when the heat-cutoff fusible conductor 10 has a coating structure in which a low-melting-point metal constituting the inner layer is coated with a high-melting-point metal or a laminated structure of low-melting-point metal and high-melting-point metal. In other words, the heat-cutoff fusible conductor 10 coated or laminated with a high-melting-point metal requires time to heat up to the temperature at which the high-melting-point metal melts, even when the heating element 5 generates heat. The protective element 60 includes multiple fusing members 61, and by simultaneously heating each heating element 5, the high-melting-point metal can be quickly heated to its melting temperature. Therefore, the protective element 60 allows the thickness of the high-melting-point metal layer constituting the outer layer to be increased, thereby achieving a higher rating and maintaining fast-fusing characteristics.

[0119] 17, the protective element 60 preferably has a pair of fusing members 61, 61 facing each other and connected to the heat generation interruption fusible conductor 10. This allows the protective element 60 to use the pair of fusing members 61, 61 to simultaneously heat the same location of the heat generation interruption fusible conductor 10 from both sides and to suck in the molten conductor 10a, allowing the heat generation interruption fusible conductor 10 to be heated and melted more quickly.

[0120] Furthermore, in the protective element 60, it is preferable that the first and second support electrodes 7, 8 formed on the insulating substrates 2 of the pair of fusing members 61, 61 face each other via the heat generation cutoff fusible conductor 10. This symmetrically connects the pair of fusing members 61, 61, which prevents the load from the fusing members 61 on the heat generation cutoff fusible conductor 10 from becoming unbalanced during reflow mounting or heating of the heat generation cutoff fusible conductor 10, and improves resistance to deformation of the heat generation cutoff fusible conductor 10 and connection misalignment of the fusing members 61.

[0121] It is preferable that the heating element 5 be formed on both sides of the conductive through-hole 63 in order to heat the first and second support electrodes 7, 8 and the heating element lead electrode 6 and to aggregate and attract a larger amount of the molten conductor 10a.

[0122] When the heat generation cutoff fusible conductor 10 of the protection element 60 melts, the power supply path of each melting member 61 to the heating element 5 is also cut off, so that the heating element 5 stops generating heat.

[0123] Furthermore, when an overcurrent flows between the first and second electrodes 3 and 4, the protection element 60 melts the current interrupting soluble conductor 11 due to self-heating. In the protection element 60, one (FIG. 22) or both (FIG. 23) of the first current interrupting soluble conductor 11A and the second current interrupting soluble conductor 11B melts. This cuts off the current path between the first and second electrodes 3 and 4.

[0124] Like the protective element 1 described above, the protective element 60 is configured as a fuse element for interrupting overcurrent by making the current-interrupting soluble conductor 11 smaller and relatively more resistant, so that the amount of vapor scattering from the molten conductor of the current-interrupting soluble conductor 11 is reduced, soot-like substances do not continue within the case 12, and the formation of a conductive path can be prevented.

[0125] [Variation 3: Surface heater sandwich structure] Next, other modified examples of the protective element to which the present technology is applied will be described. In the following description, the same components as those of the protective elements 1, 50, and 60 described above will be assigned the same reference numerals, and their details may be omitted. Figure 24 shows a protective element 70 in which a fusing member 71 having a heating element 5 formed on the surface 2a of an insulating substrate 2 is connected to one side and the other side of a heat-blocking soluble conductor 10, where (A) is a plan view and (B) is a D-D' cross-sectional view of (A). The protective element 70 shown in Figure 24 has a fusing member 71 connected to one side of the heat-blocking soluble conductor 10 and the other side opposite to the one side. That is, in the protective element 70, the heat-blocking soluble conductor 10 is sandwiched between multiple fusing members 71.

[0126] 25 is a diagram showing a fusing member 71, where (A) is a plan view showing the front surface 2a side of the insulating substrate 2 connected to the heat generation interruption fusible conductor 10, and (B) is a bottom view showing the back surface 2b side of the insulating substrate 2. The fusing member 71 has an insulating substrate 2, and on the front surface 2a of the insulating substrate 2, a heating element 5, an insulating layer 16, a first support electrode 7, a second support electrode 8, a first heating element electrode 17, a second heating element electrode 18, and a heating element lead electrode 6 are formed. On the back surface 2b of the insulating substrate 2, a holding electrode 72 is formed, which is connected to the heating element lead electrode 6 via a conductive through hole 73 and holds the molten conductor 10a of the heat generation interruption fusible conductor 10.

[0127] The fusing member 71 has two heating elements 5 formed in parallel on the surface 2a of the insulating substrate 2. One end of each heating element 5 is connected to the first heating element electrode 17, and the other end is connected to the second heating element electrode 18. Note that the protective element 70 may also be provided with one heating element 5 or three or more heating elements 5.

[0128] The first heating element electrode 17 is connected to the heating element power supply electrode 15, which is connected to an external circuit, via connection solder 13. This connects the heating element 5 to a power source provided in the external circuit, enabling power to be supplied.

[0129] The heating element 5 and parts of the first heating element electrode 17 and second heating element electrode 18 are covered with an insulating layer 16. A heating element lead electrode 6 is formed on the insulating layer 16. The heating element lead electrode 6 is formed in a position opposite to a holding electrode 73 formed in the approximate center of the rear surface 2b, with the insulating substrate 2 interposed therebetween. The heating element lead electrode 6 is also connected to the second heating element electrode 18.

[0130] The holding electrode 72 is electrically and thermally connected to the heating element extraction electrode 6 via a conductive through-hole 73 that penetrates from the surface of the holding electrode 72 to the surface of the heating element extraction electrode 6, and is also physically continuous with the same. As a result, when the molten conductor 10a of the heat generation interruption fusible conductor 10 that has melted on the heating element extraction electrode 6 is attracted to the holding electrode 72 side via the conductive through-hole 73, it can be held on the holding electrode 72.

[0131] The holding electrodes 72 can be formed by a known method such as screen printing using a known electrode material such as Ag, Cu, or an alloy material containing Ag or Cu as a main component.

[0132] When the heat generation interruption fusible conductor 10 melts, the conductive through-hole 73 attracts the molten conductor 10a of the heat generation interruption fusible conductor 10 by capillary action, thereby reducing the volume of the molten conductor 10a held on the heating element lead-out electrode 6. As a result, even if the amount of melting increases due to the increase in size of the heat generation interruption fusible conductor 10 as a result of the higher rating and higher capacity of the protective element 70, a large amount of molten conductor 10a can be held by the holding electrode 72, the heating element lead-out electrode 6, and the first and second support electrodes 7 and 8, and the heat generation interruption fusible conductor 10 can be reliably melted.

[0133] The conductive through-holes 73 are formed in areas of the insulating substrate 2 where no heating elements 5 are formed. In the fusing member 71 shown in Figures 24 and 25, the conductive through-holes 73 are formed in areas between the heating elements 5 arranged in parallel.

[0134] A conductive layer 74 is formed on the inner surface of the conductive through-hole 73. The conductive layer 74 is made of the same material as the conductive layer 64 described above. The conductive layer 74 is continuous with the holding electrode 72 and the heater element extraction electrode 6. When the heater element extraction electrode 6 is blown, the molten conductor 10a aggregates. The continuity between the heater element extraction electrode 6 and the conductive layer 74 facilitates the introduction of the molten conductor 10a into the conductive through-hole 73. The molten conductor 10a also spreads and is held by the holding electrode 72, which is continuous with the conductive layer 74. This allows a larger amount of the molten conductor 10a to be attracted and held by the conductive through-hole 73 and the holding electrode 72, reducing the volume of the molten conductor 10a held by the heater element extraction electrode 6 and the first and second support electrodes 7 and 8, ensuring reliable blowing.

[0135] The fusing member 71 may have a plurality of conductive through holes 73. This increases the number of paths for attracting the molten conductor 10a of the heat generation interruption fusible conductor 10, and quickly attracts more molten conductor 10a, thereby reducing the volume of the molten conductor 10a held by the heating element extraction electrode 6 and the first and second support electrodes 7 and 8.

[0136] [Step of forming the protective element 70] The process of forming the fusing member 71 of the protective element 70 involves first forming the first and second support electrodes 7 and 8, the first heating element electrode 17, and the second heating element electrode 18 on the front surface 2a of the insulating substrate 2 using a known forming method such as screen printing, then forming the heating element 5 and insulating layer 16, and then stacking the heating element lead electrode 6. Furthermore, a holding electrode 72 is formed on the back surface 2b of the insulating substrate 2 using a known forming method such as screen printing. After that, a through hole is formed using a drill or the like, and a conductive layer 74 is formed by plating or the like to form a conductive through-hole 73. This results in the fusing member 71.

[0137] One fusing member 71 is supported by a support column 25 and fixed in the hollow portion 22b of the case 12, and the heating element extraction electrode 6 and the first and second support electrodes 7, 8 are connected to one side of the heat interruption soluble conductor 10 by connection solder 13, and the first and second support electrodes 7, 8 are connected to the current interruption soluble conductor 11. In addition, the first heating element electrode 17 of the insulating substrate 2 is connected by connection solder 13 to the heating element power supply electrode 15 supported on the side edge portion 22a of the lower case 22.

[0138] Thereafter, the heating element lead electrode 6 and the first and second support electrodes 7, 8 of the other fusing member 71 are connected to the other surface of the heat interruption fusible conductor 10 via the connection solder 13 (see FIG. 24). Also, the first heating element electrode 17 of the insulating substrate 2 is connected to the heating element power supply electrode 15 supported on the side edge portion 22a of the lower case 22 by the connection solder 13. In addition, a support column 25 supporting the other fusing member 71 is erected on the top surface of the upper case 21 for the protection element 70, thereby making it possible to support the other fusing member 71 without swinging.

[0139] The protective element 70 has the same circuit configuration as the protective element 60 (see FIG. 20). That is, each fusing member 71 connected to one side and the other side of the heat generation cutoff soluble conductor 10 has one end of the heating element 5 formed on the surface 2a of each insulating substrate 2 connected to the heat generation cutoff soluble conductor 10 via the second heating element electrode 18 and the heating element lead electrode 6. In addition, each fusing member 71 faces each first heating element electrode 17 connected to the other end of the heating element 5, and is connected to each heating element power supply electrode 15 via a connection material such as connection solder 13. As a result, each fusing member 71 is connected to a power source for generating heat from the heating element 5 provided in the external circuit via the heating element power supply electrode 15.

[0140] The configuration and operational effects of the protection element 70 in which a pair of fusing members 71, 71 face each other and are connected to the heat generation cutoff fusible conductor 10 are similar to those of the protection element 60 described above, so details are omitted.

[0141] When each heating element 5 generates heat and the molten conductor 10a of the heat generation cutoff fusible conductor 10 aggregates on the heating element lead electrode 6, the protective element 70 guides the molten conductor 10a into the conductive through-hole 73, and causes the molten conductor 10a to wet and spread on the holding electrode 72 continuous with the conductive layer 74, and is held therein. Therefore, more molten conductor 10a can be attracted and held by the conductive through-hole 73 and the holding electrode 72, reducing the volume of the molten conductor 10a held by the heating element lead electrode 6 and the first and second support electrodes 7, 8, and ensuring reliable melting.

[0142] It is also preferable to form a plurality of conductive through holes 73 in the protective element 70. This increases the number of paths for attracting the molten conductor 10a, and allows a larger amount of the molten conductor 10a to be attracted quickly, thereby reducing the volume of the molten conductor 10a held by the heating element extraction electrode 6 and the first and second support electrodes 7 and 8.

[0143] When the heat generation cutoff fusible conductor 10 of the protection element 70 melts, the power supply path of each melting member 71 to the heating element 5 is also cut off, so that the heating element 5 stops generating heat.

[0144] In addition, when an overcurrent flows between the first and second electrodes 3 and 4, the current interruption soluble conductor 11 of the protection element 70 melts due to self-heating. In the protection element 70, one or both of the first current interruption soluble conductor 11A and the second current interruption soluble conductor 11B melts. This cuts off the current path between the first and second electrodes 3 and 4.

[0145] Like the protective element 1 described above, the protective element 70 is configured as a fuse element for interrupting overcurrent by making the current-interrupting soluble conductor 11 smaller and relatively more resistant, so that the amount of vapor scattering from the molten conductor of the current-interrupting soluble conductor 11 is reduced, soot-like substances do not continue within the case 12, and the formation of a conductive path can be prevented.

[0146] [Variation 4: Surface Mount Structure 1] Next, other modified examples of the protection element to which the present technology is applied will be described. In the following description, the same components as those of the above-described protection elements 1, 50, 60, and 70 will be given the same reference numerals, and their details may be omitted. Fig. 26 shows a surface-mount type protection element 80, where (A) is a plan view, (B) is a plan view showing the protection element 80 without the cap member 81, and (C) is a cross-sectional view taken along the line D-D' of (A).

[0147] 26, the protection element 80 is provided with first and second electrodes 3 and 4 on the surface 2a of the insulating substrate 2, and first and second external connection electrodes 82 and 83 connected to the first and second electrodes 3 and 4 are provided on the back surface 2b of the insulating substrate 2. When the protection element 80 is mounted on an external circuit board, the first and second external connection electrodes 82 and 83 are connected to the connection electrodes provided on the external circuit board, and the heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11 are incorporated into part of the current path formed on the external circuit board.

[0148] The protection element 80 has a first heating element electrode 17 provided on the front surface 2a of the insulating substrate 2, and a third external connection electrode 84 continuous with the first heating element electrode 17 provided on the back surface 2b of the insulating substrate 2. When the protection element 80 is mounted on an external circuit board, the third external connection electrode 84 is connected to a connection electrode provided on the external circuit board, thereby enabling current to flow to the heating element 5.

[0149] The insulating substrate 2 has a first electrode 3, a second electrode 4, a heating element 5, a heating element lead electrode 6, a first support electrode 7, a second support electrode 8, an insulating layer 16, a first heating element electrode 17, and a second heating element electrode 18 formed on its surface 2a. A first current interruption soluble conductor 11A is connected between the first electrode 3 and the first support electrode 7, and a second current interruption soluble conductor 11B is connected between the second electrode 4 and the second support electrode 8. In addition, a heat generation interruption soluble conductor 10 is connected between the first support electrode 7, the heating element lead electrode 6, and the second support electrode 8. The first and second current interruption soluble conductors 11A and 11B and the heat generation interruption soluble conductor 10 are connected to each electrode by a conductive bonding material such as connection solder 13.

[0150] In addition, it is preferable that the heat generation cutoff soluble conductor 10 is coated with flux 29 to prevent oxidation and improve wettability during melting. In addition, it is preferable that the cap member 81 has a support protrusion formed on the inside of the top surface, and that the flux 29 is held on the heat generation cutoff soluble conductor 10 by tension.

[0151] The configurations of the heating element 5, heating element lead electrode 6, insulating layer 16, first and second heating element electrodes 17, 18 are the same as those of the protection element 1 described above, and therefore will not be described in detail.

[0152] The first electrode 3 is formed on one of the opposing side edges of the insulating substrate 2, and the second electrode 4 is formed on the other side edge opposite the one side edge. The first and second electrodes 3, 4, like the first and second heating element electrodes 17, 18, can be formed by printing and firing a conductive paste made of, for example, Ag or Cu. Preferably, the surfaces of the first and second electrodes 3, 4 are coated with a film such as Ni / Au plating, Ni / Pd plating, or Ni / Pd / Au plating by a known method such as plating. This prevents oxidation of the first and second electrodes 3, 4, and prevents fluctuations in the rating due to increases in conduction resistance.

[0153] The first external connection electrode 82 is formed on the same side edge as the first electrode 3 and is continuous with the first electrode 3 via a castellation. The second external connection electrode 83 is formed on the same side edge as the second electrode 4 and is continuous with the second electrode 4 via a castellation. The third external connection electrode 84 is formed on the same side edge as the first heating electrode 17 and is continuous with the first heating electrode 17 via a castellation.

[0154] The first and second electrodes 3 and 4 and the first heating element electrode 17 may be provided with a restriction wall (not shown) to prevent the connection solder provided on the electrodes of the external circuit board connected to the first to third external connection electrodes 82 to 84 from melting during reflow mounting or the like, creeping up onto each electrode via castellations, and spreading over each electrode. The restriction wall can be formed using an insulating material that is not wettable by solder, such as glass, solder resist, or an insulating adhesive, and can be formed on the first and second electrodes 3 and 4 and the first heating element electrode 17 by printing or the like. The provision of the restriction wall prevents the molten connection solder from spreading over the first and second electrodes 3 and 4 and the first heating element electrode 17, thereby maintaining the connectivity between the protection element 80 and the external circuit board.

[0155] The first support electrode 7 is provided between the heater extraction electrode 6 and the first electrode 3, and is partially overlapped with, for example, the insulating layer 16. The second support electrode 8 is provided between the heater extraction electrode 6 and the second electrode 4, and is partially overlapped with, for example, the insulating layer 16.

[0156] The insulating substrate 2 has a surface 2a on which the heat interruption soluble conductor 10 and the first and second current interruption soluble conductors 11A, 11B are mounted, covered with a cap member 81. The cap member 81 protects the inside of the protective element 80 and prevents the scattering of molten material that occurs when the heat interruption soluble conductor 10 and the current interruption soluble conductor 11 melt.

[0157] The cap member 81 can be made of insulating materials such as various engineering plastics and ceramics. The cap member 81 is provided on the surface 2a of the insulating substrate 2 and fixed with an adhesive. The cap member 81 has an internal space sufficient for the molten conductor 10a to expand spherically when the heat generation interruption fusible conductor 10 melts and to aggregate on the heating element lead electrode 6 and the first and second support electrodes 7 and 8.

[0158] [Protection element manufacturing process] Next, the manufacturing process of the protection element 80 will be described. In the manufacturing process of the protection element 80, the first electrode 3, the second electrode 4, the first support electrode 7, the second support electrode 8, the first heating element electrode 17, and the second heating element electrode 18 are formed on the front surface 2a of the insulating substrate 2, which is provided with Hall through holes for castellations. Then, the heating element 5 and the insulating layer 16 are formed, and the heating element lead electrode 6 is formed on the insulating layer 16. In addition, the first external connection electrode 82, the second external connection electrode 83, and the third external connection electrode 84 are formed on the back surface 2b of the insulating substrate 2. Next, a conductive layer is formed on the castellations by plating or the like, and the first electrode 3 and the first external connection electrode 82, the second electrode 4 and the second external connection electrode 83, and the first heating element electrode 17 and the third external connection electrode 84 are connected.

[0159] Next, the heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11 are connected. The connection of the soluble conductors 10, 11 can be efficiently performed by reflow. That is, a conductive connection material such as connection solder 13 is printed on each of the first support electrode 7, the heating element lead electrode 6, and the second support electrode 8, and the heat generation interruption soluble conductor 10 is mounted between the first support electrode 7, the heating element lead electrode 6, and the second support electrode 8. In addition, a conductive connection material such as connection solder 13 is printed on each of the first electrode 3, the first support electrode 7, the second electrode 4, and the second support electrode 8, and the first current interruption soluble conductor 11A is mounted between the first electrode 3 and the first support electrode 7, and the second current interruption soluble conductor 11B is mounted between the second electrode 4 and the second support electrode 8. Thereafter, the heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11 are connected together by reflow. The method of connecting the heat interruption soluble conductor 10 and the current interruption soluble conductor 11 is not limited to reflow.

[0160] Then, a cap member 81 is connected to the surface 2a of the insulating substrate 2 on which the heat interrupting soluble conductor 10 and the current interrupting soluble conductor 11 are mounted using an adhesive or the like to cover the substrate surface, thereby obtaining a protective element 80.

[0161] The protection element 80 has a circuit configuration similar to that of the protection element 1 (see FIGS. 5 and 6). That is, the first electrode 3 of the protection element 80 is connected to the battery stack 35 via the first external connection electrode 82, and the second electrode 4 is connected to the positive terminal 30a via the second external connection electrode 83, thereby connecting the heat generation interruption soluble conductor 10 and the current interruption soluble conductor 11 in series on the charge / discharge path of the battery stack 35. Furthermore, the protection element 80 has the heating element 5 connected to the current control element 38 via the third external connection electrode 84, and the heating element 5 is connected to one end of the battery stack 35. In this way, one end of the heating element 5 is connected to one end of the battery stack 35 via the heating element lead electrode 6, the heat generation interruption soluble conductor 10, the current interruption soluble conductor 11, and the first electrode 3, and the other end is connected to the current control element 38 and the other end of the battery stack 35 via the third external connection electrode 84. This forms a power supply path to the heating element 5, the power supply of which can be controlled by the current control element .

[0162] [Protection element operation] When the heating element 5 melts the heat-exchange cutoff soluble conductor 10 due to an abnormal voltage in the battery cell, current flows from the battery stack 35 to the heating element 5, causing the heating element 5 to start generating heat. In the protective element 80, heat from the heating element 5 is transferred to the heat-exchange cutoff soluble conductor 10 via the second heating element electrode 18 and the heating element lead electrode 6, which have excellent thermal conductivity, and also via the insulating layer 16, causing the heat-exchange cutoff soluble conductor 10 to melt (FIG. 27). This cuts off the current path between the first and second electrodes 3 and 4, and cuts off the charge / discharge path of the external circuit. The protective element 80 forms the heat-blocking soluble conductor 10 in a laminated or coated structure of a high-melting point metal layer 26 and a low-melting point metal layer 27, so that the low-melting point metal layer 27 melts before the high-melting point metal layer 26 melts, and the melting action of the molten low-melting point metal layer 27 on the high-melting point metal layer 26 can be utilized to melt the heat-blocking soluble conductor 10 in a short time.

[0163] When the heat generation cutoff fusible conductor 10 melts, the protective element 80 also cuts off the power supply path to the heating element 5, so that the heating element 5 stops generating heat.

[0164] Furthermore, when an overcurrent exceeding the rated current flows between the first and second electrodes 3 and 4, the protective element 80 melts the current interrupting soluble conductor 11 due to self-heating. In the protective element 80, one (FIG. 28) or both (FIG. 29) of the first current interrupting soluble conductor 11A and the second current interrupting soluble conductor 11B melts. This cuts off the current path between the first and second electrodes 3 and 4, and cuts off the charge / discharge path of the external circuit.

[0165] When the first current interruption soluble conductor 11A and / or the second current interruption soluble conductor 11B melts, the power supply path to the heating element 5 is also cut off, and the heating element 5 stops generating heat (see FIG. 5). Similar to the protective element 1 and the like, the protective element 80 is configured as a fuse element for cutting off overcurrent by making the current interruption soluble conductor 11 small and relatively highly resistant, so that the amount of vapor scattering from the molten conductor of the current interruption soluble conductor 11 is reduced, soot-like substances do not continue within the cap member 81, and it is possible to prevent the formation of a conductive path.

[0166] [Modification of fusible conductor for current interruption] As shown in Figure 30, the protection element 80 may have a plurality of current interruption soluble conductors 11 provided between the first support electrode 7 and the first electrode 3, and between the second support electrode 8 and the second electrode 4. This makes it possible to reduce the size and increase the resistance of each current interruption soluble conductor 11, and to increase the current capacity between the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4. The plurality of current interruption soluble conductors 11 may be the same size or may be different sizes.

[0167] As shown in FIG. 31, the protective element 80 may have slits 85 located between the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4 in the current interrupting soluble conductor 11. The slits 85 are preferably located perpendicular to the current flow direction of the current interrupting soluble conductor 11. As shown in FIG. 31, the slits 85 are preferably located on both sides of the current interrupting soluble conductor 11. By narrowing the area around the slits 85, the current interrupting soluble conductor 11 has high resistance and limits the melting area, thereby reducing the amount of vapor scattering from the molten conductor when it melts due to an overcurrent. The shape of the slits 85 may be approximately triangular (FIG. 31(A)), approximately arc-shaped (FIG. 31(B)), rectangular, or other shapes.

[0168] As shown in FIG. 32, the protective element 80 may have through holes 86 located between the first support electrode 7 and the first electrode 3 and between the second support electrode 8 and the second electrode 4 in the current interrupting soluble conductor 11. A single through hole 86 may be provided, or multiple through holes 86 may be provided. For example, multiple through holes 86 may be arranged in a row in a direction perpendicular to the current flow direction of the current interrupting soluble conductor 11 (FIG. 32(A)), or multiple rows (FIG. 32(B)). Different sizes of through holes 86 may also be provided, for example, a single relatively large through hole 86 and multiple relatively small through holes 86 may be provided (FIG. 32(C)). The current interrupting soluble conductor 11 has a high resistance due to the narrowing of the periphery of the through hole 86. This limits the melting point, reducing the amount of vapor scattering from the molten conductor when it melts due to an overcurrent.

[0169] Also, in the protective element 80, the widthwise length L1 of the current interrupting soluble conductor 11, which is perpendicular to the current flow direction, may be the same as the widthwise length L2 of the heat interrupting soluble conductor 10, which is perpendicular to the current flow direction (see FIG. 12), or the widthwise length L1 may be longer than the widthwise length L2 of the heat interrupting soluble conductor 10 (see FIG. 13). Even if the widthwise length L1 of the current interrupting soluble conductor 11 is equal to or greater than the widthwise length L2 of the heat interrupting soluble conductor 10, the resistance value can be made higher than the resistance value of the heat interrupting soluble conductor by adjusting the length in the current flow direction, thickness, etc.

[0170] [Variation 5: Surface Mount Structure 2] Next, other modified examples of the protection element to which the present technology is applied will be described. In the following description, the same components as those of the above-described protection elements 1, 50, 60, 70, and 80 will be assigned the same reference numerals, and their details may be omitted. Fig. 33 is a cross-sectional view showing a surface-mount type protection element 90, Fig. 34(A) is a plan view of the protection element 90 without the cap member 81, and Fig. 34(B) is a bottom view of the protection element 90.

[0171] 33 and 34, the protective element 90 has a heating element 5, a first heating element electrode 17, a rear-side second heating element electrode 18b, and an insulating layer 16 that covers these formed on a rear surface 2b opposite to the front surface 2a of the insulating substrate 2. In addition, a first external connection electrode 82 and a second external connection electrode 83 are formed on the rear surface 2b of the insulating substrate 2.

[0172] On the surface 2a of the insulating substrate 2, first and second electrodes 3, 4, a heating element lead electrode 6, and first and second support electrodes 7, 8 are formed, and a heat generation interruption soluble conductor 10 and a current interruption soluble conductor 11 are connected, similar to the protective element 80. In addition, on the surface 2a of the insulating substrate 2, a surface-side second heating element electrode 18a is formed.

[0173] The front-side second heating element electrode 18a and the back-side second heating element electrode 18b are electrically connected by castellations formed on the side surfaces of the insulating substrate 2 or conductive through-holes penetrating the insulating substrate 2. The heating element lead electrode 6 is connected to the front-side second heating element electrode 18a, and the heating element 5 is connected to the back-side second heating element electrode 18b. That is, the heating element lead electrode 6 is electrically and thermally connected to the heating element 5 via the front-side second heating element electrode 18a and the back-side second heating element electrode 18b. As a result, in the protective element 90, the heating element 5 heats the heating element lead electrode 6 via the insulating substrate 2, and the heat of the heating element 5 is transferred to the heating element lead electrode 6 via the front-side second heating element electrode 18a and the back-side second heating element electrode 18b, which have excellent thermal conductivity, thereby heating and fusing the heat interruption fusible conductor 10.

[0174] In the protection element 90, the first heating element electrode 17 also serves as an external connection electrode connected to an electrode of an external circuit board, and therefore the third external connection electrode 84 provided in the protection element 80 is not provided. The protection element 90 may also be provided with a resistance measurement electrode 91 on the surface 2a of the insulating substrate 2. The resistance measurement electrode 91 is electrically connected to the first heating element electrode 17 via a castellation.

[0175] Other configurations and operations of the protection element 90 are the same as those of the protection element 80. In addition, the protection element 90 may also use modified examples of the current interrupting soluble conductor 11 as in the protection element 80 (see FIGS. 30 to 32, 12, and 13). [Example]

[0176] Next, an example of the present technology will be described. In this example, a protection element 1 (see FIG. 1 etc.) was used as an example, and a protection element 100 (see FIG. 35) was used as a comparative example, and voltages of 80 V, 100 V, and 150 V were applied to each to cause the fusible conductor to self-heat and melt, and then the occurrence of tracking was visually checked.

[0177] The results were rated as ◯ (OK) when no tracking occurred, and × (NG) when tracking occurred. The results are shown in Table 1.

[0178] [Table 1]

[0179] As shown in Table 1, in the protective element 1 according to the embodiment, tracking did not occur even when a voltage of 150 V was applied. This is because in the protective element 1, the resistance value of the current interrupting soluble conductor 11 is made higher than the resistance value of the heat interrupting soluble conductor 10, so the volume of the current interrupting soluble conductor is reduced. Therefore, even when the rated voltage is increased, the occurrence of sparks and tracking phenomena after overcurrent interruption can be suppressed.

[0180] On the other hand, in the protection device 100 according to the comparative example, tracking occurred when voltages of 100 V and 150 V were applied. This is because, in the protection device 100, the higher the voltage, the more soot-like debris from the melted fuse element adheres to the inner surface of the case and the surface of the insulating substrate, causing repeated sparks (discharges) between the fuse terminals after the fuse element melts, resulting in tracking. [Explanation of symbols]

[0181] 1 protective element, 2 insulating substrate, 2a surface, 2b back surface, 3 first electrode, 4 second electrode, 5 heating element, 5 heating element lead electrode, 7 first support electrode, 8 second support electrode, 8, 10 heat generation interruption fusible conductor, 11 current interruption fusible conductor, 11A first current interruption fusible conductor, 11B second current interruption fusible conductor, 12 case, 13 connection solder, 14 screw hole, 15 heating element power supply electrode, 16 insulating layer, 17 first heating element electrode, 18 second heating element electrode, 21 upper case, 22 lower case, 22a side edge portion, 22b hollow portion, 23 mating recess, 24 mating protrusion, 25 support column, 26 high melting point metal layer, 27 low melting point metal layer, 29 flux, 30 battery pack, 30a Positive electrode terminal, 30b Negative electrode terminal, 31 Battery cell, 32 Charging device, 33 Current control element, 34 Control unit, 35 Battery stack, 36 Charge / discharge control circuit, 37 Detection circuit, 38 Current control element, 41 Through hole, 42 Slit, 50 Protective element, 51 Conductive through hole, 52 Conductive through hole, 60 Protective element, 61 Fusing member, 62 Holding electrode, 63 Conductive through hole, 64 Conductive layer, 65 Castellation, 70 Protective element, 71 Holding electrode, 73 Conductive through hole, 74 Conductive layer, 80 Protective element, 81 Cap member, 82 First external connection electrode, 82 Second external connection electrode, 83 Third external connection electrode, 85 Slit, 86 Through hole, 90 Protective element, 91 Resistance measurement electrode

Claims

1. an insulating substrate; a heating element provided on the insulating substrate; a first electrode and a second electrode; a heating element extraction electrode electrically connected to the heating element on a current path between the first electrode and the second electrode; a first support electrode provided on the insulating substrate and disposed between the first electrode and the heat generating element lead electrode, and a second support electrode provided between the second electrode and the heat generating element lead electrode; A heat generation interruption fusible conductor that is connected across the first support electrode, the heating element extraction electrode, and the second support electrode and melts at least between the heating element extraction electrode and the first support electrode or between the heating element extraction electrode and the second support electrode due to heat generation by the heating element, thereby interrupting the current path; A current-interrupting fusible conductor is connected between the first support electrode and the first electrode and between the second support electrode and the second electrode, and is melted at least between the first electrode and the first support electrode or between the second electrode and the second support electrode due to self-heating caused by the passage of an overcurrent exceeding a rated value, thereby interrupting the current path. The heat generation interruption fusible conductor and the current interruption fusible conductor are connected in series, The resistance value of the current interrupting fusible conductor is higher than the resistance value of the heat generation interrupting fusible conductor, Protection element.

2. The protection element according to claim 1, wherein the resistance value of the metal constituting the current interrupting soluble conductor is lower than the resistance value of the metal constituting the heat generation interrupting soluble conductor.

3. The protection element according to claim 1 or 2, wherein the resistance value of the current interrupting soluble conductor is at least twice the resistance value of the heat generation interrupting soluble conductor.

4. The protection element according to claim 1 or 2, wherein a plurality of the current-interrupting soluble conductors are connected between the first support electrode and the first electrode and between the second support electrode and the second electrode.

5. The current interrupting soluble conductor has a through hole or a slit between the first support electrode and the first electrode, and between the second support electrode and the second electrode. The protective element according to claim 1 or 2.

6. A first current-blocking fusible conductor mounted between the first electrode and the first support electrode; A second current-blocking fusible conductor is provided between the second electrode and the second support electrode; The protection element according to claim 1 or 2, wherein a resistance value of the first current interrupting soluble conductor and a resistance value of the second current interrupting soluble conductor are different.

7. Equipped with a case, The protection element according to claim 1 , wherein the first electrode and the second electrode are supported from the inside to the outside of the case.

8. The protection element according to claim 1 , wherein the first electrode and the second electrode are formed on the insulating substrate.

9. one or more battery cells; a protection element connected to a charge / discharge path of the battery cell and blocking the charge / discharge path; a current control element that detects a voltage value of the battery cell and controls current flow to the protection element; The protective element is the protective element according to claim 1 or 2. Battery pack.

Images