JP6196856B2 - Switching circuit - Google Patents

Description

  The present invention relates to a switching circuit that switches a current path.

  Many secondary batteries that can be charged and used repeatedly are processed into battery packs and provided to users. Particularly in lithium ion secondary batteries with high weight energy density, in order to ensure the safety of users and electronic devices, in general, a battery pack incorporates a number of protection circuits such as overcharge protection and overdischarge protection, It has a function of shutting off the output of the battery pack in a predetermined case.

  This type of protection element includes an overcharge protection or overdischarge protection operation of the battery pack by turning on / off the output using an FET switch built in the battery pack. However, when the FET switch is short-circuited for some reason, a lightning surge or the like is applied and an instantaneous large current flows, or the output voltage drops abnormally due to the life of the battery cell, or excessively abnormal Even when the voltage is output, the battery pack and the electronic device must be protected from accidents such as ignition. Therefore, in order to safely shut off the output of the battery cell in any possible abnormal state, a protection element made of a fuse element having a function of cutting off the current path by an external signal is used. .

  As a protection element of a protection circuit for a lithium ion secondary battery or the like, as described in Patent Document 1, it can be extended between the first electrode, the heating element extraction electrode, and the second electrode on the current path. There is a type in which a molten conductor is connected to form a part of a current path, and the soluble conductor on the current path is melted by self-heating due to overcurrent or by a heating element provided inside the protection element. In such a protection element, the molten liquid soluble conductor is collected on the conductor layer connected to the heating element, thereby interrupting the current path.

JP 2010-003665 A JP 2004-185960 A JP 2012-003878 A

  However, even if the charging / discharging current circuit of the lithium ion secondary battery that caused the abnormality is shut off, the battery cell still stores a large amount of energy for the battery capacity. A risk such as a heat generation accident due to leakage current from the battery cell is assumed. Therefore, after the use of the battery pack is stopped, it is preferable to discharge until the internal battery cell drops to a safe voltage.

  Thus, for example, in a battery pack of a lithium ion secondary battery, an element that reliably switches the current path of the battery cell from the charge / discharge path at the normal time to the discharge path at the time of the abnormality is required.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a switching circuit that switches a current path irreversibly by interrupting a current path that is short-circuited in a normal state and short-circuiting a current path that is used in an abnormal state in a predetermined order. And

In order to solve the above-described problems, a switching circuit according to the present invention includes a first heating element that generates heat when a current flows, one end connected to the first heating element, and the other end connected to a main circuit. A short-circuitable fusible conductor, a switch having one end connected to the short-circuiting fusible conductor and the main circuit, and the other end connected to the first circuit, and the first heat generation. The short-circuited fusible conductor is blown by the heat generated by the body and the switch is short-circuited by the molten conductor , the second heating element that generates heat when current flows, and the second heating element An open-side soluble conductor having one end connected to the second circuit and the other end connected to the main circuit, and the open-side soluble conductor is heated by the heat generated by the second heating element. An open circuit for fusing, and One end of the heating element is connected to a switching element that receives a switching signal and supplies current from the main circuit to the second heating element, and the open end of the first heating element of the short circuit, The second heating element of the open circuit is connected to the connection end of the open-side soluble conductor, and the switch element is operated, whereby the second heating element of the open circuit is energized and generates heat. The open side fusible conductor is blown, the main circuit and the second circuit are cut off, and the open side fusible conductor is blown, whereby the first heating element of the short circuit is energized and generates heat. The short-circuitable soluble conductor is melted, the switch is short-circuited, and the main circuit and the first circuit are energized.

The switching circuit according to the present invention includes a first heating element that generates heat when a current flows, a short-circuitable soluble conductor having one end connected to the first heating element and the other end connected to the main circuit. And a switch having one end connected to the short circuit side soluble conductor and 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 fusible conductor is blown and the switch is short-circuited by the molten conductor , the second heating element that generates heat when a current flows, the second heating element, and one end thereof is connected to the second heating element. An open circuit that is connected to the main circuit and has the other end connected to the main circuit and has an open circuit that melts the open soluble conductor with the heat generated by the second heating element. The end of the first heating element A first switch element that receives a signal and supplies current from the main circuit to the first heating element is connected, and one end of the second heating element receives the switching signal and receives the second heating element. Is connected to the second switch element for supplying current from the main circuit, and the second switch element is operated, whereby the second heating element of the open circuit is energized and generates heat to allow the open side. The molten conductor is blown, the main circuit and the second circuit are cut off, and the first switch element is operated, whereby the first heating element of the short circuit is energized and generates heat to cause the short circuit. The side soluble conductor melts, the switch is short-circuited, and the main circuit and the first circuit are energized.

In addition, the switching circuit according to the present invention includes a first heating element that generates heat when a current flows, a short-circuit side connection in which one end is connected to the first heating element and the other end is connected to the first circuit. A heat conductor, a switch having one end connected to the short-circuitable fusible conductor and the first circuit and the other end connected to the main circuit, and the heat generated by the first heating element. The short-circuit side fusible conductor is melted by the short-circuit portion, the switch is short-circuited by the molten conductor , the second heating element that generates heat when a current flows, and the one end connected to the second heating element. An open-side soluble conductor connected to the other end of the switch and the main circuit, and the other end connected to a second circuit, and the open-side soluble conductor by heat generated by the second heating element. An opening for fusing the first The body is connected to a first switch element that receives a switching signal and supplies current from the main circuit to the first heating element, and the second heating element receives the switching signal and receives the second heating element. The body is connected to a second switch element that allows a current to flow from the main circuit, and the second switch element operates, whereby the second heating element of the open portion is energized and generates heat to open the open side. The fusible conductor is melted, the main circuit and the second circuit are cut off, and the first switch element is operated, whereby the first heating element of the short-circuit portion is energized and generates heat to The short-circuitable soluble conductor is melted, the switch is short-circuited, and the main circuit and the first circuit are energized.

According to the present invention, by operating the switch element, the current path from the main circuit to the second circuit is interrupted and the current path to the first circuit is constructed, and the current path of the main circuit is changed to the second circuit. The circuit can be switched to the first circuit. At this time, according to the present invention, the current path can be blocked and short-circuited irreversibly by melting the short-circuitable soluble conductor and the open-side soluble conductor.

1A and 1B are circuit diagrams of a short circuit constituting the switching circuit, where FIG. 1A shows a state before the short circuit and FIG. FIG. 2 is a circuit diagram of an open circuit constituting the switching circuit, where (A) shows before open and (B) shows after open. FIG. 3 is a block diagram showing a configuration of the first switching circuit. FIG. 4 is a circuit diagram showing a first switching circuit before switching, in which (A) is an example provided with two open-side soluble conductors, and (B) is an example provided with one open-side soluble conductor. Indicates. FIG. 5 is a circuit diagram showing a first switching circuit in which the second heating element is energized by the switch element. FIG. 6 is a circuit diagram showing a first switching circuit in which the first heating element is energized. FIG. 7 is a circuit diagram showing the 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 the first switching circuit according to the modification is applied. FIG. 11 is a block diagram showing a configuration of the second switching circuit. 12A and 12B are circuit diagrams showing a second switching circuit, in which FIG. 12A shows an example provided with two open-side soluble conductors, and FIG. 12B shows an example provided with one open-side soluble conductor. FIG. 13 is a circuit diagram of a battery pack to which the 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 according to a modification is applied. FIG. 16 is a circuit diagram showing a third switching circuit, in which (A) shows an example provided with two open-side soluble conductors, and (B) shows an example provided with one open-side soluble conductor. FIG. 17 is a circuit diagram of a battery pack to which the third switching circuit is applied. FIG. 18 is a circuit diagram showing a modification of the third switching circuit. FIG. 19 is a circuit diagram of a battery pack to which a third switching circuit according to a modification is applied.

  Hereinafter, a switching circuit to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The switching circuit to which the present invention is applied is a short circuit via a fusible conductor and a short circuit or a short-circuited portion where electrodes that are open to each other are connected via the molten conductor by melting the fusible conductor. Between the electrodes which are made, it has the open circuit or open part interrupted | blocked by melting a soluble conductor. First, the operation principle of the short circuit and the open circuit will be described.

  As shown in FIG. 1A, the short circuit 1 is connected in series with the first heating element 2 and the first heating element 2 and is melted by the heat generated by the first heating element 2. The conductor 3 is provided with first and second electrodes 5 and 6 that constitute a switch 4 that is open to each other and is short-circuited via the molten conductor by melting the short-circuitable soluble conductor 3. The first electrode 5 is connected to a power source (not shown), and the second electrode 6 is connected to an external circuit that is 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 so that energization is controlled.

  When the short circuit 1 is fed to the first heating element 2 through the first electrode 5 and the short-circuitable soluble conductor 3 by the operation of the switch element, as shown in FIG. The short-circuitable soluble conductor 3 is melted by the heat generated by the first heating element 2. Then, in the short circuit 1, the molten conductor of the short-circuitable soluble conductor 3 aggregates between the first and second electrodes 5 and 6, and the first and second electrodes 5 and 6 are short-circuited. As a result, in the short circuit 1, the switch 4 is turned on to energize the power source and the external circuit.

  As shown in FIG. 2A, the open circuit 10 includes a second heating element 11, an open-side soluble conductor 12 that is melted by heat generated by the second heating element 11, and an open-side soluble conductor 12. And third and fourth electrodes 13 and 14 connected to each other. The third and fourth electrodes 13 and 14 are provided on 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 be energized. Is controlled.

  When the open circuit 10 is supplied with power to the second heating element 11 through the third electrode 13 and the open-side soluble conductor 12 by the operation of the switch element, as shown in FIG. The open-side soluble conductor 12 is melted by the heat generated by the second heating element 11. Thereby, the open circuit 10 can interrupt the current path.

[First switching circuit]
As shown in FIG. 3, the first switching circuit 30 constitutes the short circuit 1. The first switching circuit 30 is connected to the power supply circuit 25 that is a main circuit and the first external circuit 23 that is energized after switching, and the open circuit The circuit 10 includes a power supply circuit 25 and an open element 22 connected to a second external circuit 24 that is energized before switching. The first switching circuit 30 supplies power to the second heating element 11 by the switch element 26 that has received the switching signal. As a result, the second heating element 11 generates heat, and after the third and fourth electrodes 13 and 14 are cut off, the first heating element 2 generates heat and the first and second electrodes 5 and 6 are heated. They 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 a circuit configuration shown in FIG. The short circuit 1 includes a first heating element 2 that generates heat when current flows, a short-circuitable soluble conductor 3 having one end connected to the first heating element 2 and the other end connected to the power supply circuit 25, The switch 4 includes one end connected to the short-circuitable soluble conductor 3 and the power supply circuit 25 and the other end 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. 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.

  The open circuit 10 is connected to the second heating element 11 that generates heat when a current flows, the second heating element 11, one end connected to the power supply circuit 25, and the other end to the second external circuit. 24 and an open-side soluble conductor 12 connected to 24. In the first switching circuit 30 shown in FIG. 4A, the open-side soluble conductor 12 has one end connected to the power supply circuit 25 via the third electrode 13 and the other end connected to the second heating element 11. The first open-side fusible conductor 12a is connected to the second external circuit 24 through the fourth electrode 14, and the other end is connected to the second heating element 11. And an open-side soluble conductor 12b.

  Note that the open circuit 10 may be configured by only the first open-side soluble conductor 12a as shown in FIG. 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 the fourth electrode 14. Connected to the second external circuit 24.

  In addition, the first switching circuit 30 receives a switching signal at one end of the second heating element 11 via the second heating element electrode 15 and supplies a current from the power supply circuit 25 to the second heating element 11. A switch element 26 to be energized is connected. The first switching circuit 30 includes a first heating element electrode 7 of the short circuit 1, and a connection end electrode 16 to which the second heating element 11 of the open circuit 10 and the open-side soluble conductor 12 are connected. It is connected.

  The switch element 26 is configured by a field effect transistor (FET), for example, and controls 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 FIG. At this time, in the first switching circuit 30, power supply to the second heating element 11 is restricted by the switch element 26, and both ends of the first heating element 2 are substantially at the same potential, Hardly flows.

  When the current path of the power supply circuit 25 needs to be switched from the second external circuit 24 to the first external circuit 23, a switching signal is output to the switch element 26. When receiving the switching signal, the switch element 26 controls the current so as to supply power to the second heating element 11. Thereby, as shown in FIG. 5, in the first switching circuit 30, the second heating element 11 of the open circuit 10 is energized and generates heat, and the open-side soluble conductor 12 is melted. Therefore, the current path from the power supply circuit 25 to the second external circuit 24 is interrupted.

  Then, as shown in FIG. 6, the current from the power supply circuit 25 flows into the short circuit 1 through the first electrode 5, and the short circuitable soluble conductor 3, the first heating element 2, and the first It flows to the open circuit 10 and the switch element 26 side through the heating element electrode 7. As a result, the first switching circuit 30 causes the first heating element 2 of the short circuit 1 to be energized and heated, and as shown in FIG. The first and second electrodes 5 and 6 are short-circuited, 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.

  The second heating element 11 stops heat generation because both the open-side soluble conductor 12 and the short-circuitable soluble conductor 3 are melted to interrupt the power supply path. Further, the first heating element 2 stops the heat generation because the power supply path is cut off when the short-circuitable soluble conductor 3 is melted.

  As described above, according to the first switching circuit 30, by operating the switch element 26, the current path from the third and fourth electrodes 13 and 14 to the second external circuit 24 is interrupted. A 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 is constructed, and the current path of the power supply circuit 25 is changed from the second external circuit 24 to the second external circuit 24. 1 external circuit 23 can be switched.

  Further, according to the first switching circuit 30, the disconnection between the third and fourth electrodes 13 and 14 and the short circuit between the first and second electrodes 5 and 6 are connected to the open-side soluble conductor 12 and the short circuit. This is performed irreversibly by melting the side soluble conductor 3. Therefore, it is possible to improve the switching failure due to malfunction and to improve the vulnerability to unauthorized switching due to cracking or the like, compared with the case of electronic switching by software or the like.

[Example of mounting the first switching circuit]
As shown in FIG. 8, such a first switching circuit 30 is used by being incorporated in a circuit in a battery pack 40 of a lithium ion secondary battery, for example. The battery pack 40 includes, 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 / discharge control circuit 50 that controls charging / discharging of the battery stack 45, and the present invention that cuts off charging when the battery stack 45 is abnormal and dissipates electrical energy in the battery stack 45. The short circuit element 21 and the open element 22 constituting the applied first switching circuit 30, the detection circuit 46 that detects the voltage of each of the battery cells 41 to 44, and the first switching according to the detection result of the detection circuit 46 And a switch element 26 that controls the operation of the circuit 30.

  The battery stack 45 includes battery cells 41 to 44 that need to be controlled for protection from overcharge and overdischarge states, and can be attached and detached via the positive terminal 40a and the negative terminal 40b of the battery pack 40. Are connected to the charging circuit 55, and the charging voltage from the charging circuit 55 is applied thereto. The battery pack 40 charged by the charging circuit 55 can operate the electronic device by connecting the positive terminal 40a and the negative terminal 40b to the electronic device that operates on the battery.

  The charge / discharge control circuit 50 controls the operation of the two current control elements 51 and 52 connected in series to the current path flowing from the battery stack 45 to the charging circuit 55. The current control elements 51 and 52 are constituted by field effect transistors (hereinafter referred to as FETs), for example, and the gate voltage is controlled by the charge / discharge control circuit 50, whereby the current path of the battery stack 45 is turned on and off. Control. The charge / discharge control circuit 50 operates by receiving power supply from the charging circuit 55, and according to the detection result of the detection circuit 46, when the battery stack 45 is overdischarged or overcharged, the current path is cut off. The operation of the current control elements 51 and 52 is controlled.

  The short-circuit element 21 is connected in parallel with the battery stack 45, and is connected in series with the protective resistor 31 for discharging the electrical energy stored in the battery stack 45 below the upper limit discharge current of the battery cells 41 to 44. Yes. Thus, the first switching circuit 30 constitutes a discharge circuit 32 provided with the short-circuit element 21 and the protective resistor 31.

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

  The detection circuit 46 is connected to each of the battery cells 41 to 44, detects the voltage value of each of the battery cells 41 to 44, and supplies each voltage value to the charge / discharge control circuit 50. Further, the detection circuit 46 outputs a control signal for controlling the switch element 26 when any one of the battery cells 41 to 44 becomes an overcharge voltage.

  The switch element 26 is configured by, for example, an FET, and when the voltage value of the battery cells 41 to 44 exceeds a predetermined overcharge state by a detection signal output from the detection circuit 46, the first switching circuit 30 The charge / discharge current circuit 33 of the battery stack 45 is shut off regardless of the switching operation of the current control elements 51 and 52, and the current path of the battery stack 45 is connected to the charge / discharge current circuit 33 via the open element 22. To the discharge path 32 via the short-circuit element 21.

  Specifically, the battery pack 40 outputs a switching signal to the switch element 26 when the detection circuit 46 detects an abnormal voltage in any of the battery cells 41 to 44. The switch element 26 controls the current of the battery stack 45 so as to energize the second heating element 11 of the open element 22. As a result, in the first switching circuit 30, the open-side soluble conductor 12 is melted and the charge / discharge current path 33 of the battery stack 45 is cut off. Further, in the first switching circuit 30, when the first heating element 2 is energized and the short-circuitable soluble conductor 2 is melted, the first and second electrodes 5 and 6 are short-circuited. The current path is switched to the discharge circuit 32 side where the protective resistor 31 is provided.

  As described above, the battery pack 40 in which the first switching circuit 30 is incorporated shuts off the charge / discharge current circuit 33 of the battery stack 45 in which an abnormality has occurred, and stores a large amount of electric energy corresponding to the battery capacity. The 45 current paths are switched to the discharge circuit 32 provided with the protective resistor 31. Therefore, after stopping use, the battery pack 40 can be discharged until the internal battery cells 41 to 44 drop to a safe voltage.

[Built-in protection element]
The first switching circuit 30 may include a protective resistor 31 on the discharge circuit 32 as shown in FIG. 8, or may incorporate the protective resistor 31 in the short circuit 1 as shown in FIG. 9. In this case, it is not necessary to provide the protective resistor 32 in the discharge circuit 32 of the battery pack 40 as shown in FIG.

[Second 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 described above are denoted by the same reference numerals, and details thereof are omitted. As shown in FIG. 11, the second switching circuit 60 constitutes the short circuit 1, and constitutes the open circuit 10 and the short circuit element 21 connected to the power circuit 25 and the first external circuit 23 that is energized after switching. And an open element 22 connected to a power supply circuit 25 and a 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 switch element 61, and the open element 22 is connected to the second switch element 62. The short-circuit element 21 is fed with power to the first heating element 2 by the first switch element 61 that has received the switching signal. The open element 22 is supplied with power to the second heating element 11 by the second switch element 62 that has received 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 open circuit by the open element 22 is changed in accordance with the output order of the switching signals to the first and second switch elements 61 and 62. Can do.

  Specifically, the second switching circuit 60 has a circuit configuration shown in FIG. The short circuit 1 includes a first heating element 2, a short circuit side soluble conductor 3, and a switch 4. The short circuit side soluble conductor 3 is melted by the heat generated by the first heating element 2, and the molten conductor To short the switch 4. In the second switching circuit 60, the short circuit 1 is the same as the first switching circuit 30 except that the first heating element 2 is connected to the first switch element 61 via the first heating element electrode 7. It is the same composition as.

  The open circuit 10 includes a second heating element 11 and an open-side soluble conductor 12, and the open-side soluble conductor 12 is blown by the heat generated by the second heating element 11. In the second switching circuit 60, the open circuit 10 is the same as the first switching circuit except that the second heating element 11 is connected to the second switch element 62 via the second heating element electrode 15. 30.

  In the second switching circuit 60 shown in FIG. 12A, the open-side soluble conductor 12 has one end connected to the power supply circuit 25 via the third electrode 13 and the other end connected to the second heating element 11. The first open-side soluble conductor 12a connected to the second external circuit 24 via the fourth electrode 14, and the other end connected to the second heating element 11 via the fourth electrode 14. 2 open-side soluble conductors 12b.

  Also in the switching circuit 60, the open circuit 10 may be configured by only the first open-side soluble conductor 12a as shown in FIG. 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 the fourth electrode 14 via the third electrode 13. 2 external circuits 24.

[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 FIG. At this time, in the short circuit 1, power supply to the first heating element 2 is restricted by the first switch element 61, and the switch 4 is turned off. In the open circuit 10, power supply to the second heating element 11 is restricted by the second switch 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, a switching signal is first output to the second switch element 62. When receiving the switching signal, the second switch 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 fused. Therefore, the current path from the power supply circuit 25 to the second external circuit 24 is interrupted.

  Next, the second switching circuit 60 outputs a switching signal to the first switch element 61. Upon receiving the switching signal, the first switch element 61 controls the current so as to supply power to the first heating element 2. As a result, the second switching circuit 60 is configured such that the first heating element 2 of the short circuit 1 is energized and generates heat, the short-circuitable soluble conductor 3 is melted, and the first and second electrodes 5 are melted by the molten conductor. , 6 are short-circuited, 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.

  The second switching circuit 60 first outputs a switching signal to the first switch element 61 when it becomes necessary to switch the current path of the power supply circuit 25 from the second external circuit 24 to the first external circuit 23. Then, after a current path from the power supply circuit 25 to the first external circuit 23 is constructed, a switching signal is output to the second switch element 62 so that the current path to the second external circuit 24 is cut off. Also good. As a result, the current path can be switched from the second external circuit 24 to the first external circuit 23 without the power of the power supply circuit 25 being interrupted.

  Note that the heat generation of the second heating element 11 is stopped because the open-side soluble conductor 12 is melted to cut off the power supply path. Further, the first heating element 2 stops the heat generation because the power supply path is cut off when the short-circuitable soluble conductor 3 is melted.

  As described above, according to the second switching circuit 60, the first and second switch elements 61 and 62 are operated to pass through the third and fourth electrodes 13 and 14 to the first external circuit 24. A 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 is constructed. Switching from the second external circuit 24 to the first external circuit 23 can be performed.

  At this time, also in the second switching circuit 60, the short circuit between the third and fourth electrodes 13 and 14 and the short circuit between the first and second electrodes 5 and 6 are opened. This is performed irreversibly by melting the side soluble conductor 12. Therefore, it is possible to improve the switching failure due to malfunction and to improve the vulnerability to unauthorized switching due to cracking or the like, compared with the case of electronic switching by software or the like.

  Further, according to the second switching circuit 60, the order of the short circuit by the short circuit element 21 and the open circuit by the open element 22 is changed according to the output order of the switching signals to the first and second switch elements 61 and 62. Can do.

[Example of mounting the second switching circuit]
Such a second switching circuit 60 is used by being incorporated in a circuit in a battery pack 40 of a lithium ion secondary battery, for example, as shown in FIG. In this case, the switching signal is sequentially output from the detection circuit 46 to the second switch element 62 and the first switch element 61, so that the charge / discharge current circuit 33 is first interrupted by the open element 22. Subsequently, the discharge circuit 32 is short-circuited by the short-circuit element 21.

  That is, when an abnormal 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 switch element 62. The second switch element 62 controls the current of the battery stack 45 so as to energize the second heating element 11 of the open element 22. Accordingly, in the second switching circuit 60, the open-side soluble conductor 12 is melted, and the charge / discharge current path 33 of the battery stack 45 is cut off. When the interruption of the charge / discharge current path 33 is detected, the detection circuit 46 then outputs a switching signal to the first switch element 61. The first switch element 61 controls the current of the battery stack 45 so as to energize the first heating element 2 of the short-circuit element 21. As a result, the first heating element 2 is energized, and the short-circuitable soluble conductor 2 is blown, whereby the first and second electrodes 5 and 6 are short-circuited, and the protection resistor 31 connects the current path of the battery stack 45. Switch to the provided discharge circuit 32 side.

  As described above, the battery pack 40 in which the second switching circuit 60 is incorporated cuts off the charge / discharge current circuit 33 of the battery stack 45 in which an abnormality has occurred, and stores a large amount of electric energy corresponding to the battery capacity. The 45 current paths are switched to the discharge circuit 32 provided with a protective resistor. Therefore, after stopping use, the battery pack 40 can be discharged until the internal battery cell drops to a safe voltage.

[Built-in protection element]
Also in the second switching circuit 60, as shown in FIG. 13, in addition to providing the protective resistor 31 on the discharge circuit 32, the short circuit 1 may incorporate the protective resistor 31 as shown in FIG. . In this case, as shown in FIG. 15, it is not necessary to provide the protective resistor 32 in the discharge circuit 32 of the battery pack 40.

[Third switching circuit]
Next, the third switching circuit 70 will be described. As shown in FIG. 16, the third switching circuit 70 is formed by integrally forming a short circuit portion 71 having the same function as the short circuit 1 described above and an open portion 72 having the same function as the open circuit 10 described above. Yes.

  The short-circuit portion 71 includes the first heat generating element 2, one end connected to the first heat generating element 2, and the other end connected to the first external circuit 23, and one end connected to the short-circuit side. The switch 4 is connected to the fusible conductor 3 and to the first external circuit 23, and the other end is connected to the power supply circuit 25.

  The open section 72 is connected to the second heating element 11 and the second heating element 11, and one end is connected to the other end of the switch 4 and the power supply circuit 25, and the other end is connected to the second external circuit 24. Open-side fusible conductor 12.

  In the short-circuit portion 71, the first heating element 2 is connected to the first switch element 61 via the first heating element electrode 7. 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. 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 switch element 62 via the second heating element electrode 15. The open portion 72 has the open-side soluble conductor 12 connected to the second external circuit 24 via the fourth electrode 14 and to the power supply circuit 25 via the second electrode 6. In the third switching circuit 70 shown in FIG. 16A, the open-side soluble conductor 12 has one end connected to the second external circuit 24 via the fourth electrode 14 and the other end to the second heating element. 11 is connected to the power circuit 25 through the second electrode 6 and the other end is connected to the second heating element 11. And an open-side soluble conductor 12b.

  In addition, you may comprise the open part 72 only with the 1st open | release side soluble conductor 12a, as shown to FIG. 16 (B). 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 the fourth electrode 14. Connected to the second external circuit 24.

[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 through the open section 72 as shown in FIG.
At this time, in the short-circuit portion 71, the power supply to the first heating element 2 is restricted by the first switch element 61, and the switch 4 is turned off. In addition, the power supply to the second heating element 11 is regulated in the open portion 72 by the second switch 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, a switching signal is first output to the second switch element 62. When receiving the switching signal, the second switch element 62 controls the current so as to supply power to the second heating element 11. Thereby, as for the 3rd switching circuit 70, the 2nd heat generating body 11 of the open part 72 energizes and heats, and the open side soluble conductor 12 melts. Therefore, the current path from the power supply circuit 25 to the second external circuit 24 is interrupted.

  Next, the third switching circuit 70 outputs a switching signal to the first switch element 61. Upon receiving the switching signal, the first switch 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-circuitable soluble conductor 3 is fused, and the first and second electrodes 5 are melted by this molten conductor. , 6 are short-circuited, 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.

  The third switching circuit 70 first outputs a switching signal to the first switch element 61 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. Then, after a current path from the power supply circuit 25 to the first external circuit 23 is constructed, a switching signal is output to the second switch element 62 so that the current path to the second external circuit 24 is cut off. Also good. As a result, the current path can be switched from the second external circuit 24 to the first external circuit 23 without the power of the power supply circuit 25 being interrupted.

  Note that the heat generation of the second heating element 11 is stopped because the open-side soluble conductor 12 is melted to cut off the power supply path. Further, the first heating element 2 stops the heat generation because the power supply path is cut off when the short-circuitable soluble conductor 3 is melted.

  As described above, according to the third switching circuit 70, the first and second switch elements 61 and 62 are operated to pass through the second and fourth electrodes 6 and 14 to the first external circuit 24. A current path from the power supply circuit 25 to the first external circuit 23 via the second electrode 6, the switch 4, and the first electrode 5 is constructed. Switching from the second external circuit 24 to the first external circuit 23 can be performed.

  At this time, in the third switching circuit 70 as well, the short circuit between the second and fourth electrodes 6 and 14 and the short circuit between the first and second electrodes 5 and 6 are opened. This is performed irreversibly by melting the side soluble conductor 12. Therefore, it is possible to improve the switching failure due to malfunction and to improve the vulnerability to unauthorized switching due to cracking or the like, compared with the case of electronic switching by software 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 open circuit by the open element 22 is changed in accordance with the output order of the switching signals to the first and second switch elements 61 and 62. Can do.

[Example of mounting the third switching circuit]
As shown in FIG. 17, such a third switching circuit 70 is used by being incorporated in a circuit in a battery pack 40 of a lithium ion secondary battery, for example. In this case, the first switch element 61 connects between the first heating element electrode 7 of the switching circuit 70 and the + side terminal of the battery stack 45. The second switch element 62 connects the second heating element electrode 15 of the switching circuit 70 and the negative terminal of the battery stack 45. In the switching circuit 70, the first electrode 5 connected to the negative terminal of the battery stack 45 has a negative potential, and the second electrode 6 connected to the positive terminal of the battery stack 45 has a positive potential. The first heating element electrode 7 connected to the first switch element 61 is set to a positive potential. In the switching circuit 70, the fourth electrode 14 connected to the charge / discharge current circuit 33 is set to a positive potential, and the second heating element electrode 15 connected to the second switch element 62 is set to a negative potential. .

  In the battery pack 40, when a voltage abnormality is detected in any of the battery cells 41 to 44, a switching signal is sequentially output from the detection circuit 46 to the second switch element 62 and the first switch element 61. Thus, the charging / discharging current circuit 33 is first interrupted by the open portion 72, and then the discharging circuit 32 is short-circuited by the short-circuit portion 71.

  That is, when an abnormal 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 switch element 62. The second switch element 62 controls the current of the battery stack 45 so that the second heating element 11 of the open part 72 is energized. Accordingly, in the third switching circuit 70, the open-side soluble conductor 12 is melted, and the charge / discharge current path 33 of the battery stack 45 is cut off. When the interruption of the charge / discharge current path 33 is detected, the detection circuit 46 then outputs a switching signal to the first switch element 61. The first switch 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. As a result, the first heating element 2 is energized, and the short-circuitable soluble conductor 2 is blown, whereby the first and second electrodes 5 and 6 are short-circuited, and the protection resistor 31 connects the current path of the battery stack 45. Switch to the provided discharge circuit 32 side.

  Thus, the battery pack 40 incorporating the third switching circuit 70 shuts off the charging / discharging current circuit 33 of the battery stack 45 in which an abnormality has occurred, and stores a large amount of electric energy corresponding to the battery capacity. The 45 current paths are switched to the discharge circuit 32 provided with a protective resistor. Therefore, after stopping use, the battery pack 40 can be discharged until the internal battery cell drops to a safe voltage.

[Built-in protection element]
Also in the third switching circuit 70, as shown in FIG. 17, in addition to providing the protective resistor 31 on the discharge circuit 32, the protective resistor 31 may be built in the short circuit portion 71 as shown in FIG. . In this case, as shown in FIG. 19, it is not necessary to provide the protective resistor 32 in the discharge circuit 32 of the battery pack 40.

[Industrial applicability]
According to the present invention, the first external circuit 23 is a light emitting circuit, a sound generation circuit, a circuit accompanied by an electric signal generation, or the like, so that the state where the open circuit 10 or the open part 72 is operated is notified to the outside as an alarm. It can also be applied to an open circuit with an alarm function.

  Further, according to the present invention, it can be applied as a circuit for activation of various devices and software. For example, the first external circuit 23 is configured as a functional circuit of various devices and software, and the second external circuit 24 is configured as a circuit in which a part of the function is limited. The external circuit 24 is connected. When the user performs a license contract procedure and activates the device, the user is switched to the first external circuit 23 that is a functional circuit of the device.

  The present invention can also be applied as an information security circuit for protecting database information. For example, the second external circuit 24 is configured as a functional circuit connected to a database, and the first external circuit 23 is configured as a circuit separated from the database. In the initial setting, the database is connected via the second external circuit 24. Is accessible. When hacking or cracking is detected, the first external circuit 23 separated from the database is switched to protect the information in the database.

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

DESCRIPTION OF SYMBOLS 1 Short circuit, 2 1st heat generating body, 3 Short circuit side soluble conductor, 4 Switch, 5 1st electrode, 6 2nd electrode, 7 1st heat generating body electrode, 10 Open circuit, 11 2nd heat generation Body, 12 open-side soluble conductor, 13 third electrode, 14 fourth electrode, 15 second heating element electrode, 16 connection end electrode, 21 short-circuit element, 22 open element, 23 first external circuit, 24 2nd external circuit, 25 power supply circuit, 26 switch element, 30 1st switching circuit, 31 protection resistance, 32 discharge circuit, 33 charge / discharge current circuit, 40 battery pack, 41-44 battery cell, 45 battery stack, 46 Detection circuit, 50 charge / discharge control circuit, 51 current control element, 52 current control element, 55 charging circuit, 60 second switching circuit, 61 first switch element, 62 second switch element, 70 3 of the switching circuit, 71 short circuit portion 72 opening

Claims (20)

A first heating element that generates heat when a current flows; a short-circuitable soluble conductor having one end connected to the first heating element and the other end connected to a main circuit; and one end connected to the short-circuiting soluble conductor is connected is connected to the main circuit, and a switch whose other end is connected to the first circuit, to blow the short side friendly溶導body by heat generated in the first heating element and the molten A short circuit that short-circuits the switch with a conductor ;
A second heating element that generates heat when current flows, and an open-side soluble conductor that is connected to the second heating element, has one end connected to the second circuit, and the other end connected to the main circuit An open circuit for fusing the open-side soluble conductor with the heat generated by the second heating element,
One end of the second heating element is connected to a switching element that receives a switching signal and supplies current from the main circuit to the second heating element.
Connecting the open end of the first heating element of the short circuit and the connection end of the second heating element and the open-side soluble conductor of the open circuit;
When the switch element operates, the second heating element of the open circuit is energized and generates heat, the open-side soluble conductor is melted, and the main circuit and the second circuit are cut off,
Due to the melting of the open-side soluble conductor, the first heating element of the short circuit is energized and generates heat, the short-side soluble conductor is melted, the switch is short-circuited, and the main circuit and the first Switching circuit that is energized with the circuit. The main circuit is a power supply system circuit having a battery stack,
The first circuit is a discharge circuit that discharges electricity of the battery stack ,
The second circuit is a charge / discharge current circuit of the battery stack,
The open circuit cuts off the power supply system circuit and the charge / discharge current circuit to stop charging the battery stack, and the short circuit connects the power supply system circuit and the discharge circuit to accumulate in the battery stack. The switching circuit according to claim 1, wherein the electrical energy discharged is discharged.   The switching circuit according to claim 2, wherein a protective resistor is provided at the other end of the switch of the short circuit to discharge the electrical energy accumulated in the battery stack at a value equal to or lower than the upper limit discharge current of the battery cell.   3. The switching according to claim 2, wherein the discharge circuit is connected to a second end of the switch of the short circuit in which a protective resistor for discharging the electric energy accumulated in the battery stack at a discharge current equal to or lower than an upper limit discharge current of the battery cell. circuit.   The open side fusible conductor has one end connected to the main circuit and the other end connected to the second heating element, and one end connected to the second circuit and the other. 5. The switching circuit according to claim 1, further comprising a second open-side soluble conductor having an end connected to the second heating element. A first heating element that generates heat when a current flows; a short-circuitable soluble conductor having one end connected to the first heating element and the other end connected to a main circuit; and one end connected to the short-circuiting soluble conductor is connected is connected to the main circuit, and a switch whose other end is connected to the first circuit, to blow the short side friendly溶導body by heat generated in the first heating element and the molten A short circuit that short-circuits the switch with a conductor ;
A second heating element that generates heat when current flows, and an open-side soluble conductor that is connected to the second heating element, has one end connected to the second circuit, and the other end connected to the main circuit An open circuit for fusing the open-side soluble conductor with the heat generated by the second heating element,
One end of the first heating element is connected to a first switch element that receives a switching signal and energizes the first heating element from the main circuit,
One end of the second heating element is connected to a second switch element that receives a switching signal and energizes the second heating element from the main circuit,
When the second switch element operates, the second heating element of the open circuit is energized and generates heat, so that the open-side soluble conductor is blown, and the main circuit and the second circuit are cut off. And
When the first switch element operates, the first heating element of the short circuit is energized and generates heat, the short-circuitable soluble conductor is melted, the switch is short-circuited, and the main circuit and the above A switching circuit in which the first circuit is energized. The main circuit is a power supply system circuit having a battery stack,
The first circuit is a discharge circuit that discharges electricity of the battery stack ,
The second circuit is a charge / discharge current circuit of the battery stack,
The second switch element is operated, the power supply system circuit and the charge / discharge current circuit are shut off by the open circuit to stop charging the battery stack, and then the first switch element is operated to operate the short circuit The switching circuit according to claim 6, wherein the electric energy accumulated in the battery stack is discharged by short-circuiting the power supply system circuit and the discharge circuit.   The switching circuit according to claim 7, wherein a protective resistor is provided at the other end of the switch of the short-circuit circuit for discharging at or below the upper limit discharge current of the electric energy battery cell accumulated in the battery stack.   The discharge circuit is provided with a protective resistor between the other end of the switch of the short circuit and for discharging the electric energy accumulated in the battery stack at a value equal to or lower than the upper limit discharge current of the battery cell. Item 8. The switching circuit according to Item 7.   7. The first switch element is operated to short-circuit the first circuit by the short circuit, and then the second switch element is operated to cut off the second circuit by the open circuit. Switching circuit.   7. The second switch element is operated to shut off the second circuit by the open circuit, and then the first switch element is operated to short-circuit the first circuit by the short circuit. Switching circuit.   The open side fusible conductor has one end connected to the main circuit and the other end connected to the second heating element, and one end connected to the second circuit and the other. The switching circuit according to claim 6, further comprising a second open-side fusible conductor having an end connected to the second heating element. A first heating element that generates heat when a current flows; a short-circuitable soluble conductor having one end connected to the first heating element and the other end connected to the first circuit; And a switch connected to the first circuit and having the other end connected to the main circuit, and the short-circuitable soluble conductor is blown by the heat generated by the first heating element. A short-circuit portion for short-circuiting the switch by a molten conductor ;
A second heating element that generates heat when a current flows and the second heating element are connected, and one end is connected to the other end of the switch and the main circuit, and the other end is connected to the second circuit. An open side soluble conductor, and an open part that melts the open side soluble conductor with heat generated by the second heating element,
The first heating element is connected to a first switch element that receives a switching signal and energizes the first heating element from the main circuit;
The second heating element is connected to a second switch element that receives a switching signal and energizes the second heating element from the main circuit,
When the second switch element operates, the second heating element of the open portion is energized and generates heat, so that the open-side soluble conductor is blown, and the main circuit and the second circuit are cut off. And
When the first switch element operates, the first heating element of the short-circuit portion is energized and generates heat, the short-circuitable soluble conductor is melted, the switch is short-circuited, and the main circuit and the A switching circuit in which the first circuit is energized. The main circuit is a power supply system circuit having a battery stack,
The first circuit is a discharge circuit that discharges electricity of the battery stack ,
The second circuit is a charge / discharge current circuit of the battery stack,
The second switch element is operated, the power supply system circuit and the charge / discharge current circuit are shut off by the open part to stop charging the battery stack, and then the first switch element is operated to short-circuit the battery. The switching circuit according to claim 13, wherein the electric power stored in the battery stack is discharged by short-circuiting the power supply system circuit and the discharge circuit by a unit.   The switching circuit according to claim 14, wherein a protective resistor is provided at the other end of the switch of the short-circuit portion to discharge the electric energy accumulated in the battery stack at a value equal to or lower than the upper limit discharge current of the battery cell.   The discharge circuit is provided with a protective resistor between the other end of the switch of the short-circuit portion for discharging the electrical energy accumulated in the battery stack at a value equal to or lower than the upper limit discharge current of the battery cell. Item 15. The switching circuit according to Item 14.   14. The first switch element is operated to short-circuit the first circuit by the short-circuit portion, and then the second switch element is operated to cut-off the second circuit by the open-circuit portion. Switching circuit.   14. The second switch element is operated to shut off the second circuit by the open part, and then the first switch element is operated to short-circuit the first circuit by the short circuit part. Switching circuit.   The open-side fusible conductor has one end connected to the second circuit and the other end connected to the second heating element, and one end connected to the main circuit and the other. The switching circuit according to any one of claims 13 to 18, further comprising a second open-side soluble conductor connected to the second heating element at an end.   14. The switching circuit according to claim 1, wherein the first circuit is a light emitting circuit, a sound generation circuit, or a circuit accompanied by electronic signal generation.

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