TW201517107A - Switching circuit - Google Patents

Abstract

The invention blocks a short circuit of a current path and opens a short circuit of a current path according to a specific order, and irreversibly switches the current path. A second heating element 11 connects to a switching element 26 that turns on current through the second heating element 11, the switching element 26 connecting an open terminal of a first heating element 2 with the second heating element 11 and the connecting terminal 16 of an opening side fusible conductor 12; the second heating element 11 is electrified and generates heat by operating switching element 26, the fuse is blown on the opening side fusible conductor 12, and thus a main circuit 25 and a second circuit 24 are cut off; by blowing the fuse of the opening side fusible conductor 12, the first heating element 2 is electrified and generates heat, and by blowing the fuse on a short-circuit side fusible conductor 3, a switch 4 short-circuits, and the main circuit 25 and the first circuit 23 is electrified.

Description

Switching circuit

The present invention relates to a switching circuit for switching a current path.

Most rechargeable and reusable secondary batteries are processed into battery packs for delivery to the user. In particular, in a lithium ion secondary battery having a high weight and energy density, in order to secure the safety of the user and the electronic device, in general, several types of protection circuits such as overcharge protection and overdischarge protection are built in the battery pack, and have a predetermined The function of blocking the output of the battery pack in case.

Among such protection elements, there is a case where the output is turned on/off (ON/OFF) using a field-effect transistor (FET) switch built in the battery pack, thereby performing a battery pack. Charge protection or over-discharge protection operation. However, in the case where the FET switch is short-circuited for some reason, a lightning surge or the like is applied to instantaneously flow a large current, or a voltage is output due to the life of the battery cell. In the case of an abnormal drop or an abnormally large abnormal voltage, the battery pack or the electronic device needs to be protected from accidents such as a fire. Therefore, in order to safely block the output of the battery unit in any of the conceivable abnormal conditions, a fuse-containing component is used. A protection element having a function of blocking a current path by a signal from the outside.

As a protective element for a protective circuit of a lithium ion secondary battery or the like, there is a protective element as disclosed in Patent Document 1 in which a first electrode across a current path, a heating element extraction electrode, and a second electrode are connected and fusible The conductor is also a part of the current path, and the fusible conductor on the current path is blown by self-heating of the overcurrent or a heat generating body provided inside the protective element. In such a protective element, the molten liquid-like fusible conductor is concentrated on the conductor layer connected to the heat generating body, thereby blocking the current path.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-003665

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-185960

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2012-003878

However, even if the charge/discharge current circuit of the lithium ion secondary battery in which the abnormality has occurred is blocked, the battery unit stores a large amount of energy equivalent to the battery capacity, and when an abnormality occurs in the protection circuit, it is assumed that there is a source of the battery. The leakage current of the unit causes a risk of heat accidents. Therefore, it is preferable to discharge the internal battery cells until the safety voltage is lowered after the battery pack is stopped.

Thus, in a battery pack such as a lithium ion secondary battery, it is required to have the following The component, that is, can reliably switch the current path of the battery cell from the normal charge and discharge path to the abnormal discharge path.

Accordingly, it is an object of the present invention to provide a switching circuit that blocks a short-circuit current path in a normal order in a predetermined order, shorts a current path used in an abnormal state, and irreversibly switches the current path.

In order to solve the above problem, the switching circuit of the present invention includes a short circuit including: a first heat generating body that generates heat by a current flowing, and one end is connected to the first heat generating body, and the other end is connected to a short-circuit side fusible conductor connected to the main circuit, and a switch having one end connected to the short-circuit side fusible conductor and connected to the main circuit and the other end connected to the first circuit, and the heat generated by the first heating element The short-circuit-side soluble conductor is blown, and the switch is short-circuited by the molten conductor, and the open circuit includes a second heat generating body that generates heat by a current flowing, and is connected to the second heat generating body And an open-side fusible conductor connected to the second circuit at one end and connected to the main circuit at the other end, and the open-side fusible conductor is blown by heat generated by the second heat generating body, and the second heat is generated a switching element is connected to one end of the body, and the switching element receives a switching signal to energize a current from the main circuit to the second heating element, and opens an open end of the first heating element of the short circuit Description The second heating element of the discharge circuit is connected to the connection end of the open-side soluble conductor, and the second heating element of the open circuit is energized and generates heat by the operation of the switching element, and the open side is Melting the fuse, thereby blocking the main circuit and the second circuit, by blowing the open side fusible conductor, The first heat generating body of the short circuit is energized and generates heat, and the short-circuit-side meltable conductor is melted to short-circuit the switch, and the main circuit and the first circuit are energized.

Further, the switching circuit of the present invention includes a short circuit including a first heat generating body that generates heat by a current flowing, and one end connected to the first heat generating body and the other end connected to the main circuit. a short-circuit-side fusible conductor, and a switch having one end connected to the short-circuit-side soluble conductor and connected to the main circuit and the other end connected to the first circuit, the short circuit being caused by heat generated by the first heat generating body The side fusible conductor is blown, and the switch is short-circuited by the molten conductor, the open circuit including: a second heat generating body that generates heat by a current flowing, and a second heat generating body connected to the second heat generating body a circuit-connected open-side fusible conductor connected to the main circuit at the other end, wherein the open-side fusible conductor is blown by heat generated by the second heat generating body, and is connected at one end of the first heat generating body a first switching element that receives a switching signal to energize a current from the main circuit to the first heating element, and a second switching element is connected to one end of the second heating element Second switch element Receiving a switching signal to energize a current from the main circuit to the second heating element, and operating the second switching element, the second heating element of the open circuit is energized and generates heat, and the open side The fusible conductor is blown to block the main circuit and the second circuit, and the first switching element operates, and the first heating element of the short circuit is energized and generates heat, and the short-circuit side is The fuse conductor is fused to short the switch and energize the primary circuit and the first circuit.

Further, the switching circuit of the present invention includes a short-circuit portion and an open portion, and the short-circuit portion includes a first heat-generating body that generates heat by a current flowing, one end of which is connected to the first heat-generating body, and the other end of which is connected to the first circuit a short-circuit-side fusible conductor, and a switch having one end connected to the short-circuit-side soluble conductor and connected to the first circuit and the other end connected to the main circuit, wherein the heat generated by the first heat generating body causes the The short-circuit-side fusible conductor is blown, and the switch is short-circuited by the molten conductor, and the open portion includes a second heat-generating body that generates heat by a current flowing, and is connected to the second heat-generating body and has one end and An open-side fusible conductor connected to the other end of the switch and the main circuit and connected to the second circuit at the other end, and the open-side fusible conductor is blown by heat generated by the second heating element, The first heating element is connected to the first switching element, and the first switching element receives a switching signal to energize a current from the main circuit to the first heating element, and the second heating element is connected to the second switching element. The second switching element receives the cut The signal is exchanged to cause current to be supplied from the main circuit to the second heat generating body, and the second switching element operates, and the second heat generating body of the open portion is energized and generates heat, and the open side may be The fuse is blown to block the main circuit and the second circuit, and the first switching element operates, and the first heating element of the short-circuit portion is energized and generates heat, and the short-circuit side is meltable The conductor is fused to short the switch and energize the primary circuit and the first circuit.

According to the present invention, by operating the switching element, the current path from the main circuit to the second circuit can be blocked, and the current path to the first circuit can be constructed. And the current path of the main circuit can be switched from the second circuit to the first circuit. At this time, according to the present invention, the current path can be irreversibly blocked and short-circuited by melting the first open-side meltable conductor.

1‧‧‧Short circuit

2‧‧‧1st heating element

3‧‧‧ Short-circuit side fusible conductor

4‧‧‧ switch

5‧‧‧1st electrode

6‧‧‧2nd electrode

7‧‧‧1st heating element electrode

10‧‧‧Open circuit

11‧‧‧2nd heating element

12‧‧‧Open side fusible conductor

12a‧‧‧1st open side fusible conductor

12b‧‧‧2nd open side fusible conductor

13‧‧‧3rd electrode

14‧‧‧4th electrode

15‧‧‧2nd heating element electrode

16‧‧‧Connecting electrode

21‧‧‧Short-circuit components

22‧‧‧Open components

23‧‧‧1st external circuit

24‧‧‧2nd external circuit

25‧‧‧Power circuit

26‧‧‧Switching elements

30‧‧‧1st switching circuit

31‧‧‧Protection resistance

32‧‧‧Discharge circuit

33‧‧‧Charge and discharge current circuit

40‧‧‧Battery Pack

40a‧‧‧positive terminal

40b‧‧‧Negative terminal

41~44‧‧‧ battery unit

45‧‧‧Battery stack

46‧‧‧Detection circuit

50‧‧‧Charge and discharge control circuit

51, 52‧‧‧ Current control components

55‧‧‧Charging circuit

60‧‧‧2nd switching circuit

61‧‧‧1st switching element

62‧‧‧2nd switching element

70‧‧‧3rd switching circuit

71‧‧‧ Short circuit

72‧‧‧Open Department

1(A) and 1(B) are circuit diagrams of a short-circuit circuit constituting a switching circuit. FIG. 1(A) shows a short circuit and FIG. 1(B) shows a short circuit.

2(A) and 2(B) are circuit diagrams of an open circuit constituting a switching circuit, and FIG. 2(A) shows before opening, and FIG. 2(B) shows after opening.

3 is a block diagram showing the configuration of a first switching circuit.

4(A) and 4(B) are circuit diagrams showing a first switching circuit before switching, and FIG. 4(A) shows an example in which two open-side fusible conductors are provided, and FIG. 4(B) shows that one is open. An example of a side fusible conductor.

FIG. 5 is a circuit diagram showing a first switching circuit that energizes the second heating element by the switching element.

FIG. 6 is a circuit diagram showing a first switching circuit that energizes the first heating element.

FIG. 7 is a circuit diagram showing a first switching circuit after switching.

Fig. 8 is a circuit diagram of a battery pack to which the first switching circuit is applied.

FIG. 9 is a circuit diagram showing a modification of the first switching circuit.

Fig. 10 is a circuit diagram of a battery pack to which a first switching circuit of a modification is applied.

Fig. 11 is a block diagram showing the configuration of a second switching circuit.

12(A) and 12(B) are circuit diagrams showing the second switching circuit, and Fig. 12 (A) shows an example in which two open-side fusible conductors are provided, and FIG. 12(B) shows an example in which one open-side fusible conductor is provided.

Fig. 13 is a circuit diagram of a battery pack to which a second switching circuit is applied.

FIG. 14 is a circuit diagram showing a modification of the second switching circuit.

Fig. 15 is a circuit diagram of a battery pack to which a second switching circuit of a modification is applied.

16(A) and 16(B) are circuit diagrams showing a third switching circuit. Fig. 16(A) shows an example in which two open-side fusible conductors are provided, and Fig. 16(B) shows an open side fusible. An example of a conductor.

Fig. 17 is a circuit diagram of a battery pack to which a third switching circuit is applied.

FIG. 18 is a circuit diagram showing a modification of the third switching circuit.

19 is a circuit diagram of a battery pack to which a third switching circuit of a modification is applied.

Hereinafter, the switching circuit to which the present invention is applied will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention. Moreover, the drawing is a schematic diagram, and the ratio of each dimension may be different from the actual case. The specific dimensions and the like should be judged by referring to the following description. Moreover, the drawings naturally include portions having different dimensional relationships or ratios from each other.

The switching circuit to which the present invention is applied includes: a short circuit or a short-circuit portion that connects between electrodes that are open to each other via the molten conductor by melting the fusible conductor; and an open circuit or an open portion by melting the fusible conductor The electrodes that are short-circuited via the fusible conductor are blocked. First, the short circuit and the open circuit The operation principle is explained.

As shown in FIG. 1(A), the short circuit 1 includes a first heat generating element 2 and a short-circuit-side soluble conductor 3 connected in series with the first heat generating body 2 and melted by heat generation of the first heat generating body 2; The first electrode 5 and the second electrode 6 are open to each other, and the short-circuit-side soluble conductor 3 is melted, and a short circuit is generated via the molten conductor to constitute the switch 4. The first electrode 5 is connected to a power supply (not shown), and the second electrode 6 is connected to an external circuit connected when the switch 4 is turned on. Further, the first heating element 2 is connected to a switching element such as an FET (not shown) via the first heating element electrode 7, and controls energization.

When the short-circuiting circuit 1 operates by the switching element and supplies power to the first heating element 2 via the first electrode 5 and the short-circuit-side soluble conductor 3, the heat of the first heating element 2 is generated as shown in FIG. 1(B). The short-circuit side fusible conductor 3 is blown. Then, in the short circuit 1 , the molten conductor of the short-circuit-side soluble conductor 3 converges between the first electrode 5 and the second electrode 6 , and the first electrode 5 and the second electrode 6 are short-circuited. Thereby, the switch 4 of the short circuit 1 is turned on to energize the power supply and the external circuit.

As shown in FIG. 2(A), the open circuit 10 includes a second heat generating body 11 , an open side fusible conductor 12 that is blown by heat generation of the second heat generating body 11 , and an open side soluble conductor 12 connected thereto. The third electrode 13 and the fourth electrode 14. The third electrode 13 and the fourth electrode 14 are provided in the current path, and the second heating element 11 is connected to a switching element such as an FET (not shown) via the second heating element electrode 15 to control energization.

When the open circuit 10 operates by the switching element and supplies power to the second heating element 11 via the third electrode 13 and the open-side soluble conductor 12, as shown in FIG. 2(B), The open-side fusible conductor 12 is blown by the heat generation of the second heating element 11. Thereby, the open circuit 10 can block the current path.

[1st switching circuit]

As shown in FIG. 3, the first switching circuit 30 includes a short-circuit element 21, constitutes a short-circuit circuit 1, and is connected to a power supply circuit 25 that is a main circuit and a first external circuit 23 that is energized after switching, and an open element 22 that is open. The circuit 10 is connected to the power supply circuit 25 and the second external circuit 24 that is energized before switching. Further, the first switching circuit 30 supplies power to the second heating element 11 by the switching element 26 that receives the switching signal. As a result, the second heating element 11 generates heat, and after the third electrode 13 and the fourth electrode 14 are blocked, the first heating element 2 generates heat, and the first electrode 5 and the second electrode 6 are short-circuited. Thereby, the first switching circuit 30 can switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23.

Specifically, the first switching circuit 30 has the circuit configuration shown in FIGS. 4(A) and 4(B). The short circuit 1 includes a first heat generating body 2 that generates heat by a current flow, and a short-circuit side meltable conductor 3, one end of which is connected to the first heat generating body 2 and the other end of which is connected to the power supply circuit 25; and the switch 4, one end and a short circuit The side fusible conductor 3 is connected and connected to the power supply circuit 25, and the other end is connected to the first external circuit 23.

The switch 4 is connected to the power supply circuit 25 via the first electrode 5, and is connected to the first external circuit 23 via the second electrode 6. Further, the first heating element 2 is connected to the connection end electrode 16 of the open circuit 10 via the first heating element electrode 7.

Further, the open circuit 10 includes a second heat generating body 11 that generates heat by a current flowing therethrough, and an open side fusible conductor 12 that is connected to the second heat generating body 11 and One end is connected to the power supply circuit 25 and the other end is connected to the second external circuit 24. In the first switching circuit 30 shown in FIG. 4(A), the open-side fusible conductor 12 includes a first open-side soluble conductor 12a, and one end thereof is connected to the power supply circuit 25 via the third electrode 13, and the other end is connected. The second open-side fusible conductor 12b is connected to the second open-side fusible conductor 12b, and one end is connected to the second external circuit 24 via the fourth electrode 14, and the other end is connected to the second heat-generating body 11.

Further, as shown in FIG. 4(B), the open circuit 10 may include only the first open-side fusible conductor 12a. In this case, one end of the first open-side soluble conductor 12a is connected to the power supply circuit 25 via the third electrode 13, and the other end is connected to the second heating element 11 and is connected to the second external circuit 24 via the fourth electrode 14. .

Further, the first switching circuit 30 is connected to the switching element 26 via the second heating element electrode 15 at one end of the second heating element 11, and the switching element 26 receives a switching signal to cause a current from the power supply circuit 25 to the second heating element 11 power ups. Further, the first switching circuit 30 connects the first heating element electrode 7 of the short circuit 1 and the connection terminal electrode 16, and the connection terminal electrode 16 is connected to the second heating element 11 and the open side fusible conductor 12 of the open circuit 10. .

The switching element 26 includes, for example, a field effect transistor (FET), and controls the conduction and interruption of the current path to the second heating element 11 by controlling the gate voltage.

[Operation of the first switching circuit]

In the initial state, the first switching circuit 30 having such a configuration becomes a current path from the power supply circuit 25 to the second external circuit 24 via the open circuit 10 as shown in FIGS. 4(A) and 4(B). At this time, the first switching circuit 30 is provided by the switching element In addition, the power supply to the second heating element 11 is restricted, and both ends of the first heating element 2 have substantially the same potential, so that the current hardly flows to the short circuit 1.

When it is necessary to switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23, a switching signal is output to the switching element 26. When the switching element 26 receives the switching signal, the switching element 26 controls the current so as to supply power to the second heating element 11. As a result, as shown in FIG. 5, the first switching circuit 30 energizes and heats the second heating element 11 of the open circuit 10, and the open-side soluble conductor 12 is blown. Therefore, the current path from the power supply circuit 25 to the second external circuit 24 is blocked.

Then, as shown in FIG. 6, the current from the power supply circuit 25 flows into the short circuit 1 via the first electrode 5, and flows to the open circuit via the short-circuit-side soluble conductor 3, the first heat-generating body 2, and the first heat-generating body electrode 7. 10 and the switching element 26 side, whereby the first heating element 2 of the short circuit 1 is energized and generates heat in the first switching circuit 30, and as shown in FIG. 7, the short-circuit-side fusible conductor 3 is blown, and the molten conductor is used. The short circuit between the first electrode 5 and the second electrode 6, that is, the switch 4 is turned on, and a current path from the power supply circuit 25 to the first external circuit 23 is constructed.

Further, the second heating element 11 is blocked by both the open-side fusible conductor 12 and the short-circuit-side soluble conductor 3, and the power supply path is blocked, so that the heat generation is stopped. Further, the first heating element 2 is blown by the short-circuit-side fusible conductor 3 to block the power supply path, and thus the heat generation is stopped.

By operating the switching element 26, the current switching path to the second external circuit 24 via the third electrode 13 and the fourth electrode 14 can be blocked by the first switching circuit 30, and the first switching circuit 30 can be constructed from the power supply circuit 25 via the first Electrode 5, switch 4, 2nd The electrode 6 reaches the current path of the first external circuit 23, thereby switching the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23.

In the first switching circuit 30, the open-side soluble conductor 12 and the short-circuit-side soluble conductor 3 are melted, and the third electrode 13 and the fourth electrode 14 are not irreversibly blocked and the first electrode 5 is Short circuit between the second electrodes 6. Therefore, compared with the case of electronically switching by software or the like, it is possible to improve the switching failure caused by the malfunction, and it is possible to improve the vulnerability to the fraudulent switching caused by cracking or the like.

[Example of installation of the first switching circuit]

As shown in FIG. 8, the first switching circuit 30 is used, for example, in a circuit incorporated in the battery pack 40 of a lithium ion secondary battery. The battery pack 40 has, for example, a battery stack 45 including battery cells 41 to 44 of a total of four lithium ion secondary batteries.

The battery pack 40 includes a battery stack 45, a charge and discharge control circuit 50 for controlling charging and discharging of the battery stack 45, and a short circuit member 21 and an open member 22, which are configured to block charging and cause the battery stack 45 to be in an abnormal state when the battery stack 45 is abnormal. The electric energy heat is applied to the first switching circuit 30 of the present invention; the detecting circuit 46 detects the voltage of each of the battery cells 41 to 44; and the switching element 26 detects the first switching circuit 30 based on the detection result of the detecting circuit 46. The operation is controlled.

The battery unit 41 to the battery unit 44 are connected in series in the battery stack 45. The battery unit 41 to the battery unit 44 need to be controlled to protect them from overcharge and overdischarge conditions. The battery stack 45 is connected to the positive terminal of the battery pack 40. 40a, The negative electrode terminal 40b is detachably connected to the charging circuit 55, and a charging voltage from the charging circuit 55 is applied. The positive electrode terminal 40a and the negative electrode terminal 40b are connected to an electronic device that operates using a battery by the battery pack 40 charged by the charging circuit 55, whereby the electronic device can be operated.

The charge and discharge control circuit 50 controls the operation of the two current control elements 51 and the current control elements 52 connected in series to the current path from the battery stack 45 toward the charging circuit 55. The current control element 51 and the current control element 52 include, for example, a field effect transistor (hereinafter referred to as an FET), and the gate voltage is controlled by the charge and discharge control circuit 50, thereby controlling the conduction and blocking of the current path of the battery stack 45. . The charge and discharge control circuit 50 operates by receiving a power supply from the charging circuit 55. When the battery stack 45 is over-discharged or over-charged according to the detection result of the detection circuit 46, the current control element 51 is blocked in such a manner as to block the current path. The operation of current control element 52 is controlled.

The short-circuiting element 21 is connected in parallel with the battery stack 45, and is connected in series with a protection resistor 31 for discharging the electric energy accumulated in the battery stack 45 to below the upper limit discharge current of the battery unit 41 to the battery unit 44. Thereby, the first switching circuit 30 constitutes the discharge circuit 32 in which the short-circuiting element 21 and the protective resistor 31 are provided.

The open element 22 is connected to the charge and discharge current circuit 33 between the battery stack 45 and the charging circuit 55, and its operation is controlled by the switching element 26.

The detection circuit 46 is connected to each of the battery cells 41 to 44, and detects the voltage values of the battery cells 41 to 44, and supplies the voltage values. Up to the charge and discharge control circuit 50. Further, when any of the battery cells 41 to 44 is overcharged, the detection circuit 46 outputs a control signal for controlling the switching element 26.

The switching element 26 includes, for example, an FET. When the voltage value of the battery cells 41 to 44 exceeds a predetermined overcharge state by the detection signal output from the detection circuit 46, the first switching circuit 30 operates. The charge and discharge current circuit 33 of the battery stack 45 is blocked depending on the switching operation of the current control element 51 and the current control element 52, and is controlled such that the current path of the battery stack 45 is switched from the charge and discharge current circuit 33 via the open element 22. To the discharge circuit 32 via the short-circuiting element 21.

Specifically, when the abnormality voltage is detected in any of the battery cells 41 to 44 by the detection circuit 46, the battery pack 40 outputs a switching signal to the switching element 26. The switching element 26 controls the current of the battery stack 45 such that the second heating element 11 of the open element 22 is energized. Thereby, in the first switching circuit 30, the open-side fusible conductor 12 is blown, and the charge and discharge current circuit 33 of the battery stack 45 is blocked. Further, the first switching circuit 30 energizes the first heating element 2, and the short-circuit-side soluble conductor 2 is blown, whereby the first electrode 5 and the second electrode 6 are short-circuited, and the current path of the battery stack 45 is switched to the protective resistor 31. The discharge circuit 32 side.

In this manner, the battery pack 40 in which the first switching circuit 30 is incorporated blocks the charge/discharge current circuit 33 of the battery stack 45 in which the abnormality has occurred, and switches the current path of the battery stack 45 in which the large electric energy corresponding to the battery capacity is stored. The discharge circuit 32 is provided with a protection resistor 31. Therefore, the battery pack 40 can be internal after being stopped. The battery cells 41 to 44 are discharged until they fall to a safe voltage.

[Built-in protection component]

Further, as shown in FIG. 8, the first switching circuit 30 may include a protective resistor 31 in the short circuit 1 as shown in FIG. In this case, as shown in FIG. 10, it is not necessary to provide the protective resistor 31 on the discharge circuit 32 of the battery pack 40.

[2nd switching circuit]

Next, the second switching circuit 60 will be described. In the following description, the same components as those of the first switching circuit 30 are denoted by the same reference numerals, and their details are omitted. As shown in FIG. 11, the second switching circuit 60 includes a short-circuit element 21, a short-circuit circuit 1, a power supply circuit 25, and a first external circuit 23 that is energized after switching, and an open element 22, which constitutes an open circuit 10. It is connected to the power supply circuit 25 and the second external circuit 24 that is energized before switching.

In the second switching circuit 60, the short-circuit element 21 is connected to the first switching element 61, and the open element 22 is connected to the second switching element 62. The short-circuiting element 21 supplies power to the first heating element 2 by the first switching element 61 that receives the switching signal. Further, the open element 22 supplies power to the second heating element 11 by the second switching element 62 that receives the switching signal. Therefore, according to the second switching circuit 60, the order of the short circuit by the short-circuit element 21 and the opening by the open element 22 can be changed in accordance with the order of output of the switching signals of the first switching element 61 and the second switching element 62.

Specifically, the second switching circuit 60 has the circuit configuration shown in FIGS. 12(A) and 12(B). The short circuit 1 includes a first heating element 2 and a short-circuit side fusible conductor 3 and the switch 4, the short-circuit-side soluble conductor 3 is blown by the heat generated by the first heat generating body 2, and the switch 4 is short-circuited by the molten conductor. In the second switching circuit 60, the short-circuiting circuit 1 has the same configuration as that of the first switching circuit 30 except that the first heating element 2 is connected to the first switching element 61 via the first heating element electrode 7.

Further, the open circuit 10 includes the second heat generating body 11 and the open side soluble conductor 12, and the open side soluble conductor 12 is blown by the heat generated by the second heat generating body 11. In the second switching circuit 60, the open circuit 10 has the same configuration as the first switching circuit 30 except that the second heating element 11 is connected to the second switching element 62 via the second heating element electrode 15.

Further, in the second switching circuit 60 shown in FIG. 12(A), the open-side fusible conductor 12 includes the first open-side fusible conductor 12a, and one end thereof is connected to the power supply circuit 25 via the third electrode 13, so that the other One end is connected to the second heating element 11 , and the second open side fusible conductor 12 b is connected to the second external circuit 24 via the fourth electrode 14 and the other end to the second heating element 11 .

Further, in the switching circuit 60, as shown in FIG. 12(B), the open circuit 10 may include only the first open-side soluble conductor 12a. In this case, one end of the first open-side soluble conductor 12a is connected to the power supply circuit 25 via the third electrode 13, and the other end is connected to the second external circuit 24 via the second heating element 11 and the fourth electrode 14.

[Operation of the second switching circuit]

In the initial state, the second switching circuit 60 having such a configuration forms a current path from the power supply circuit 25 to the second external circuit 24 via the open circuit 10 as shown in FIGS. 12(A) and 12(B). At this time, the short circuit 1 is replaced by the first switching element 61. The power supply to the first heating element 2 is restricted, and the switch 4 is turned off. Further, the open circuit 10 restricts the supply of power to the second heating element 11 by the second switching element 62.

When it is necessary to switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23, the switching signal is first output to the second switching element 62. When receiving the switching signal, the second switching element 62 controls the current so as to supply power to the second heating element 11. As a result, in the second switching circuit 60, the second heating element 11 of the open circuit 10 is energized and generates heat, and the open-side soluble conductor 12 is blown. Therefore, the current path from the power supply circuit 25 to the second external circuit 24 is blocked.

Then, the second switching circuit 60 outputs a switching signal to the first switching element 61. When receiving the switching signal, the first switching element 61 controls the current so as to supply power to the first heating element 2. In the second switching circuit 60, the first heating element 2 of the short circuit 1 is energized and generates heat, and the short-circuit-side soluble conductor 3 is blown, and the first electrode 5 and the second electrode 6 are short-circuited by the molten conductor. That is, the switch 4 is turned on to construct a current path from the power supply circuit 25 to the first external circuit 23.

Further, when the second switching circuit 60 needs to switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23, it is also possible to first output a switching signal to the first switching element 61 and construct it from the power supply circuit 25. After the current path of the first external circuit 23, a switching signal is output to the second switching element 62, thereby blocking the current path to the second external circuit 24. Thereby, the power of the power supply circuit 25 is not interrupted, and the current path can be switched from the second external circuit 24 to the first external circuit 23.

Further, in the second heating element 11, the open side fusible conductor 12 is blown The power supply path is blocked, and the heat is stopped. Further, the first heating element 2 is blown by the short-circuit-side fusible conductor 3 to block the power supply path, and thus the heat generation is stopped.

In the second switching circuit 60, the first switching element 61 and the second switching element 62 are operated, and the current path that reaches the first external circuit 23 via the third electrode 13 and the fourth electrode 14 is blocked and constructed. The current path from the power supply circuit 25 to the first external circuit 23 via the first electrode 5, the switch 4, and the second electrode 6 can switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23.

At this time, in the second switching circuit 60, the short-circuit side soluble conductor 3 and the open-side soluble conductor 12 are also melted, and the blocking between the third electrode 13 and the fourth electrode 14 and the first electrode are irreversibly performed. 5. Short circuit between the second electrodes 6. Therefore, the switching failure caused by the malfunction can be improved compared to the case of electronically switching by software or the like, and the vulnerability to fraudulent switching due to cracking or the like can be improved.

Further, according to the second switching circuit 60, the order of the short circuit by the short-circuit element 21 and the opening by the open element 22 can be changed in accordance with the output order of the switching signals of the first switching element 61 and the second switching element 62.

[Example of installation of the second switching circuit]

As shown in FIG. 13, the second switching circuit 60 is used, for example, in a circuit incorporated in the battery pack 40 of a lithium ion secondary battery. In this case, the detection circuit 46 sequentially outputs the switching signal to the second switching element 62 and the first switching element 61. First, the charging/discharging current circuit 33 is blocked by the opening element 22, and then The short-circuiting element 21 performs a short circuit of the discharge circuit 32.

In other words, when the abnormality voltage is detected in any of the battery cells 41 to 44 by the detection circuit 46, the battery pack 40 first outputs a switching signal to the second switching device 62. The second switching element 62 controls the current of the battery stack 45 so that the second heating element 11 of the open element 22 is energized. Thereby, in the second switching circuit 60, the open-side soluble conductor 12 is blown, and the charge and discharge current circuit 33 of the battery stack 45 is blocked. When the blocking of the charge and discharge current circuit 33 is sensed, the detection circuit 46 outputs a switching signal to the first switching element 61. The first switching element 61 controls the current of the battery stack 45 so that the first heating element 2 of the short-circuiting element 21 is energized. Thereby, the first heating element 2 is energized, and the short-circuit-side soluble conductor 3 is blown, whereby the first electrode 5 and the second electrode 6 are short-circuited, thereby switching the current path of the battery stack 45 to the discharge circuit provided with the protective resistor 31. 32 sides.

In this way, the battery pack 40 in which the second switching circuit 60 is mounted blocks the charge/discharge current circuit 33 of the battery stack 45 in which the abnormality has occurred, and the current path of the battery stack 45 in which the large electric energy corresponding to the battery capacity is stored is Switch to the discharge circuit 32 provided with the protection resistor. Therefore, after the battery pack 40 is stopped, the internal battery unit can be discharged until it is lowered to a safe voltage.

[Built-in protection component]

Further, in the second switching circuit 60, as shown in FIG. 13, in addition to the protection resistor 31 provided in the discharge circuit 32, as shown in FIG. 14, the protection resistor 31 may be incorporated in the short circuit 1. In this case, as shown in FIG. 15, it is not necessary to provide the protective resistor 31 on the discharge circuit 32 of the battery pack 40.

[3rd switching circuit]

Next, the third switching circuit 70 will be described. As shown in FIGS. 16(A) and 16(B), the third switching circuit 70 has a short-circuit portion 71 having the same function as the short-circuit circuit 1 and an open portion 72 having the same function as the open circuit 10. form.

The short-circuit portion 71 includes a first heat-generating body 2 and a short-circuit-side meltable conductor 3, one end of which is connected to the first heat-generating body 2, the other end of which is connected to the first external circuit 23, and the switch 4 whose one end is connected to the short-circuit-side meltable conductor 3. The other end is connected to the first external circuit 23, and the other end is connected to the power supply circuit 25.

The open portion 72 includes a second heat generating body 11 and an open side fusible conductor 12 connected to the second heat generating body 11 and having one end connected to the other end of the switch 4 and the power supply circuit 25, and the other end connected to the second external circuit 24.

In the short-circuit portion 71, the first heating element 2 is connected to the first switching element 61 via the first heating element electrode 7. Further, in the short-circuit portion 71, the switch 4 is connected to the first external circuit 23 via the first electrode 5, and is connected to the power supply circuit 25 via the second electrode 6. Further, the second electrode 6 is also connected to one end side of the open-side soluble conductor 12 provided in the open portion 72.

In the opening portion 72, the second heating element 11 is connected to the second switching element 62 via the second heating element electrode 15. Further, in the open portion 72, the open-side soluble conductor 12 is connected to the second external circuit 24 via the fourth electrode 14, and is connected to the power supply circuit 25 via the second electrode 6. In the third switching circuit 70 shown in FIG. 16A, the open-side fusible conductor 12 includes a first open-side soluble conductor 12a, and one end thereof is connected to the second external circuit 24 via the fourth electrode 14. The other end and the second heating element 11 and the second open-side fusible conductor 12b are connected to the power supply circuit 25 via the second electrode 6, and the other end is connected to the second heating element 11.

Further, as shown in FIG. 16(B), the opening portion 72 may include only the first open-side fusible conductor 12a. In this case, one end of the first open-side soluble conductor 12a is connected to the power supply circuit 25 via the second electrode 6, and the other end is connected to the second heating element 11 and is connected to the second external circuit 24 via the fourth electrode 14. .

[Operation of the third switching circuit]

In the initial state, the third switching circuit 70 having such a configuration forms a current path from the power supply circuit 25 to the second external circuit 24 via the open portion 72 as shown in FIGS. 16(A) and 16(B). At this time, the short-circuit portion 71 restricts the supply of power to the first heating element 2 by the first switching element 61, and the switch 4 is turned off. Further, the opening portion 72 restricts the supply of power to the second heating element 11 by the second switching element 62.

When it is necessary to switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23, the switching signal is first output to the second switching element 62. When receiving the switching signal, the second switching element 62 controls the current so as to supply power to the second heating element 11. As a result, in the third switching circuit 70, the second heating element 11 of the opening portion 72 is energized and generates heat, and the open-side fusible conductor 12 is blown. Therefore, the current path from the power supply circuit 25 to the second external circuit 24 is blocked.

Then, the third switching circuit 70 outputs a switching signal to the first switching element 61. When receiving the switching signal, the first switching element 61 controls the current so as to supply power to the first heating element 2. As a result, in the third switching circuit 70, the first heating element 2 of the short-circuit portion 71 is energized and generates heat, and the short-circuit-side soluble conductor 3 is blown, and by the melting The conductor is short-circuited between the first electrode 5 and the second electrode 6, that is, the switch 4 is turned on, thereby constructing a current path from the power supply circuit 25 to the first external circuit 23.

Further, when the third switching circuit 70 needs to switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23, it is also possible to first output a switching signal to the first switching element 61 and construct it from the power supply circuit 25. After the current path of the first external circuit 23, a switching signal is output to the second switching element 62, thereby blocking the current path to the second external circuit 24. Thereby, the power of the power supply circuit 25 is not interrupted, and the current path can be switched from the second external circuit 24 to the first external circuit 23.

Further, the second heating element 11 is blown by the open-side fusible conductor 12, and the power supply path is blocked, so that the heat generation is stopped. Further, the first heating element 2 is blown by the short-circuit side fusible conductor 3, and the power supply path is blocked, so that the heat generation is stopped.

In the third switching circuit 70, the first switching element 61 and the second switching element 62 are operated to block the current path that has passed through the second electrode 6 and the fourth electrode 14 to the first external circuit 24, and to construct The current path of the first external circuit 23 is reached from the power supply circuit 25 via the second electrode 6, the switch 4, and the first electrode 5, so that the current path of the power supply circuit 25 can be switched from the second external circuit 24 to the first external circuit 23. .

At this time, in the third switching circuit 70, the short-circuit side soluble conductor 3 and the open-side soluble conductor 12 can be melted, and the blocking between the second electrode 6 and the fourth electrode 14 and the first electrode can be performed irreversibly. 5. Short circuit between the second electrodes 6. Therefore, the switching caused by the malfunction can be improved compared to the case of electronically switching by software. Poor, and can improve the vulnerability to improper switching caused by cracking or the like.

Further, according to the third switching circuit 70, the order of the short circuit by the short-circuit element 21 and the opening by the open element 22 can be changed in accordance with the output order of the switching signals of the first switching element 61 and the second switching element 62.

[Example of installation of the third switching circuit]

As shown in FIG. 17, the third switching circuit 70 is used, for example, in a circuit incorporated in the battery pack 40 of a lithium ion secondary battery. In this case, the first switching element 61 connects the first heating element electrode 7 of the switching circuit 70 and the positive (+) side terminal of the battery stack 45. Further, the second switching element 62 connects the second heat generating body electrode 15 of the switching circuit 70 and the negative (-) side terminal of the battery stack 45. Further, in the switching circuit 70, the first electrode 5 connected to the -side terminal of the battery stack 45 is set to the -potential, and the second electrode 6 connected to the +side terminal of the battery stack 45 is set to the + potential, and the first switching element The first heating element electrode 7 connected to 61 is set to a + potential. In the switching circuit 70, the fourth electrode 14 connected to the charge/discharge current circuit 33 is set to the + potential, and the second heat generating body electrode 15 connected to the second switching element 62 is set to the - potential.

When the battery unit 40 detects a voltage abnormality in any of the battery unit 41 to the battery unit 44, the detection circuit 46 sequentially outputs a switching signal to the second switching element 62 and the first switching element 61, thereby first borrowing The charge/discharge current circuit 33 is blocked by the open portion 72, and then the short circuit portion 71 short-circuits the discharge circuit 32.

That is, in the case where the battery unit 40 detects an abnormal voltage in any of the battery unit 41 to the battery unit 44 by the detecting circuit 46, the second opening is first performed. The off element 62 outputs a switching signal. The second switching element 62 controls the current of the battery stack 45 so that the second heating element 11 of the opening portion 72 is energized. Thereby, in the third switching circuit 70, the open-side fusible conductor 12 is blown, and the charge and discharge current circuit 33 of the battery stack 45 is blocked. When the blocking of the charge and discharge current circuit 33 is sensed, the detection circuit 46 outputs a switching signal to the first switching element 61. The first switching element 61 controls the current of the battery stack 45 so that the first heating element 2 of the short-circuit portion 71 is energized. Thereby, the first heating element 2 is energized, the short-circuit-side soluble conductor 2 is blown, and the first electrode 5 and the second electrode 6 are short-circuited, and the current path of the battery stack 45 is switched to the discharge circuit 32 side where the protective resistor 31 is provided. .

In this manner, the battery pack 40 in which the third switching circuit 70 is mounted blocks the charge/discharge current circuit 33 of the battery stack 45 in which the abnormality has occurred, and switches the current path of the battery stack 45 in which the large electric energy corresponding to the battery capacity is stored. The discharge circuit 32 is provided with a protection resistor. Therefore, after the battery pack 40 is stopped, the internal battery unit can be discharged until it is lowered to a safe voltage.

[Built-in protection component]

Further, in the third switching circuit 70, as shown in FIG. 17, in addition to the protection resistor 31 provided in the discharge circuit 32, as shown in FIG. 18, the protection resistor 31 may be incorporated in the short-circuit portion 71. In this case, as shown in FIG. 19, it is not necessary to provide the protective resistor 31 on the discharge circuit 32 of the battery pack 40.

[Industrial availability]

According to the present invention, the first external circuit 23 can be applied to the following alarms by using a light-emitting circuit, a sounding circuit, a circuit generated by an electronic signal, or the like. The open circuit of the function, that is, the state in which the open circuit 10 or the open portion 72 operates is notified to the outside as an alarm.

Moreover, according to the present invention, it can also be applied as a circuit for activating various devices or software. For example, the first external circuit 23 is a functional circuit of various devices or software, and the second external circuit 24 is configured as a circuit that limits the functions of the part. In the initial setting, the second external circuit whose function is restricted is connected. twenty four. When the user goes through the license agreement procedure and activates the device, the user switches to the first external circuit 23 which is the functional circuit of the device.

Moreover, according to the present invention, it can be applied as an information security circuit for protecting information of a database. For example, the second external circuit 24 is configured as a functional circuit connected to the database, and the first external circuit 23 is configured as a circuit that is disconnected from the database. In the initial setting, the database can be accessed via the second external circuit 24. Access. In the case where the intrusion or the crack is sensed, in order to protect the information in the database, the first external circuit 23 disconnected from the database is switched.

In the present invention, since the switching of the functional circuit is performed by the blowing of the short-circuit-side soluble conductor 3 and the open-side fusible conductor 12, the switching of the function can be controlled physically and irreversibly. Therefore, unlike the case where the circuit is electronically switched by the software, it is possible to improve the switching failure caused by the malfunction or to improve the vulnerability to the fraudulent switching due to tampering, cracking, or the like.

21‧‧‧Short-circuit components

22‧‧‧Open components

23‧‧‧1st external circuit

24‧‧‧2nd external circuit

25‧‧‧Power circuit

26‧‧‧Switching elements

30‧‧‧1st switching circuit

Claims (20)

A switching circuit includes: a short circuit including a first heat generating body that generates heat by a current flowing, a short-circuit side fusible conductor whose one end is connected to the first heat generating body, and the other end is connected to the main circuit, and one end and the a switch in which the short-circuit side fusible conductor is connected and connected to the main circuit and the other end is connected to the first circuit, and the short-circuit side fusible conductor is blown by heat generated by the first heat generating body, and The molten conductor short-circuits the switch, and the open circuit includes a second heat generating body that generates heat by a current flowing, and is connected to the second heat generating body, and one end is connected to the second circuit, and the other end is connected to the main circuit. a connected open side fusible conductor, the open side fusible conductor being blown by heat generated by the second heating element, and a switching element connected to one end of the second heating element, the switching element receiving a switching signal And energizing a current from the main circuit to the second heat generating body, and opening an open end of the first heat generating body of the short circuit and the second heat generating body and the open side of the open circuit Fusible conductor Connected to the terminal, the second heating element of the open circuit is energized and generates heat by the operation of the switching element, and the open-side fusible conductor is blown to block the main circuit and the second circuit. The first heat generating body of the short circuit is energized and generates heat by the melting of the open side fusible conductor, and the short side meltable conductor is melted to short the switch and the main circuit The first circuit is energized. The switching circuit of claim 1, wherein The main circuit is a power supply circuit having a battery stack, the first circuit is a discharge circuit for discharging electricity of the battery stack, and the second circuit is a charge and discharge current circuit of the battery stack, An open circuit for blocking the power supply circuit and the charge and discharge current circuit and stopping charging of the battery stack, wherein the power supply circuit and the discharge circuit are short-circuited by the short circuit to accumulate The electrical energy within the stack is discharged. The switching circuit of claim 2, wherein a protective resistor is disposed at the other end of the switch of the short circuit, the protective resistor is configured to discharge electrical energy accumulated in the battery stack to the battery The upper limit discharge current of the unit is below. The switching circuit according to claim 2, wherein in the discharge circuit, a protection resistor is connected to the other end of the switch of the short circuit, and the protection resistor is used to accumulate in the battery stack. The electrical energy is discharged below the upper limit discharge current of the battery unit. The switching circuit according to any one of claims 1 to 4, wherein the open-side fusible conductor comprises: a first open-side fusible conductor, one end connected to the main circuit and the other end being The second heating element is connected to the second open-side fusible conductor, and one end is connected to the second circuit and the other end is connected to the second heating element. A switching circuit comprising: The short circuit includes a first heat generating body that generates heat by a current flowing, a short-circuit side fusible conductor whose one end is connected to the first heat generating body, and whose other end is connected to the main circuit, and one end and the short-circuit side meltable conductor a switch connected to and connected to the main circuit and connected to the first circuit at the other end, the short-circuit side fusible conductor being blown by heat generated by the first heat generating body, and the said conductor is made by the molten conductor The switch is short-circuited, and the open circuit includes a second heat generating body that generates heat by a current flowing, and an open side fuse that is connected to the second heat generating body and has one end connected to the second circuit and the other end connected to the main circuit. The conductor causes the open-side fusible conductor to be blown by heat generated by the second heat generating body, and a first switching element is connected to one end of the first heat generating body, and the first switching element receives a switching signal a current is supplied from the main circuit to the first heating element, and a second switching element is connected to one end of the second heating element, and the second switching element receives a switching signal to cause a current to flow from the main circuit The second heating body Electric electricity is operated by the second switching element, and the second heating element of the open circuit is energized and generates heat, and the open-side fusible conductor is blown to block the main circuit and the second circuit. When the first switching element operates, the first heating element of the short circuit is energized and generates heat, and the short-circuit-side soluble conductor is melted to short-circuit the switch, and the main circuit and the main circuit are The first circuit is energized. The switching circuit of claim 6, wherein The main circuit is a power supply circuit having a battery stack, the first circuit is a discharge circuit for discharging electricity of the battery stack, and the second circuit is a charge and discharge current circuit of the battery stack, The second switch operates to block the power system circuit and the charge and discharge current circuit by the open circuit, and stops charging the battery stack, and then operates the first switching element by using The short circuit circuit shorts the power supply circuit to the discharge circuit to discharge electrical energy accumulated in the battery stack. The switching circuit of claim 7, wherein a protection resistor is disposed at the other end of the switch of the short circuit, and the protection resistor is configured to discharge to an electric energy battery accumulated in the battery stack. The upper limit discharge current of the unit is below. The switching circuit according to claim 7, wherein in the discharge circuit, a protection resistor is disposed between the other end of the switch and the short circuit, and the protection resistor is used to accumulate The electrical energy within the stack is discharged below the upper limit discharge current of the battery unit. The switching circuit according to claim 6, wherein the first switching element is operated to short-circuit the first circuit by the short circuit, and then the second switching element is operated by The open circuit blocks the second circuit. The switching circuit according to claim 6, wherein the second switching element is operated to block the second circuit by the open circuit, and then the first switching element is operated and borrowed By the short circuit The first circuit is shorted. The switching circuit according to any one of claims 6 to 11, wherein the open-side fusible conductor comprises: a first open-side fusible conductor, one end connected to the main circuit and the other end being The second heating element is connected to the second open-side fusible conductor, and one end is connected to the second circuit and the other end is connected to the second heating element. A switching circuit includes: a short-circuit portion including a first heat-generating body that generates heat by a current flowing, a short-circuit-side fusible conductor whose one end is connected to the first heat-generating body, and the other end of which is connected to the first circuit, and one end and a switch connected to the short-circuit side fusible conductor and connected to the first circuit and connected to the main circuit at the other end, the short-circuit side fusible conductor being blown by heat generated by the first heat generating body, and by The molten conductor short-circuits the switch, and the open portion includes a second heat generating body that generates heat by a current flowing, and another end connected to the second heat generating body and one end of the switch and the main circuit An open-side fusible conductor connected to the other end and connected to the second circuit, wherein the open-side fusible conductor is blown by heat generated by the second heat-generating body, and the first heat-generating body is connected to the first switching element. The first switching element receives a switching signal to energize a current from the main circuit to the first heating element, the second heating element is connected to a second switching element, and the second switching element receives a switching signal Current from the main circuit Energizing the second heating element, the second switching element is operated, and the second heating of the opening portion The body is energized and generates heat, and the open-side fusible conductor is blown to block the main circuit and the second circuit, and the first heating element is operated by the first switching element, and the first heating element of the short-circuit portion When energized and heated, the short-circuit side fusible conductor is melted to short-circuit the switch and energize the main circuit and the first circuit. The switching circuit according to claim 13, wherein the main circuit is a power supply circuit having a battery stack, and the first circuit is a discharge circuit that discharges electricity of the battery stack, the second circuit a charge and discharge current circuit of the battery stack, the second switch is operated to block the power supply system circuit and the charge and discharge current circuit by the open portion, and stop charging the battery stack Then, the first switching element is operated to short-circuit the power supply circuit and the discharge circuit by the short-circuit portion, and the electric energy stored in the battery stack is discharged. The switching circuit of claim 14, wherein a protective resistor is disposed at the other end of the switch of the short-circuit portion, the protective resistor is configured to discharge electric energy accumulated in the battery stack to the battery The upper limit discharge current of the unit is below. The switching circuit according to claim 14, wherein in the discharge circuit, a protection resistor is disposed between the other end of the switch and the short circuit portion, and the protection resistor is used to accumulate The electrical energy within the stack is discharged below the upper limit discharge current of the battery unit. The switching circuit of claim 13, wherein The first switching element is operated to short-circuit the first circuit by the short-circuit portion, and then the second switching element is operated to block the second circuit by the opening portion. The switching circuit according to claim 13, wherein the second switching element is operated to block the second circuit by the opening portion, and then the first switching element is operated and utilized The short-circuit portion short-circuits the first circuit. The switching circuit according to any one of claims 13 to 18, wherein the open-side fusible conductor comprises: a first open-side fusible conductor, one end connected to the second circuit and the other end And the second open-side fusible conductor, one end of which is connected to the main circuit and the other end of which is connected to the second heat generating body. The switching circuit according to any one of the preceding claims, wherein the first circuit is a light emitting circuit, a sounding circuit, or a circuit generated with an electronic signal.