DC short-circuit protection device

Abstract

The present invention comprises: a fuse that has a busbar and that cuts the busbar in accordance with an ignition signal; a first current sensing unit that has a first resistance part and that senses a current flowing through the busbar; and a second current sensing unit that has a second resistance part and that senses a current flowing through the busbar. The first resistance part and the second resistance part are integrally formed with the busbar so that currents flowing therethrough are to have the same magnitude as the current flowing through the busbar. In accordance with the ignition signal, the busbar is cut between the first current sensing unit and the second current sensing unit, or the first resistance part of the first current sensing unit is cut.

Description

DC Short Circuit Protection Device

[0001] The present disclosure relates to a DC short circuit protection device.

[0002] Patent Document 1 describes a technique for reducing the size of an electric circuit breaker by integrating a sensor for detecting a current with the electric circuit breaker.

[0003] Japanese Patent Application Laid-Open No. 2020-136055

[0004] However, when a sensor such as a shunt resistor is built into the electrical circuit breaker described in Patent Document 1, the shunt resistor generates a large amount of heat when a current flows through it, making it difficult to dissipate the heat. In particular, when an active-type fuse is installed in a vehicle such as an electric car, a large current must be passed through it, which generates a corresponding amount of heat and necessitates measures to dissipate the heat.

[0005] Therefore, the present disclosure provides a DC short circuit protection device that can easily dissipate heat.

[0006] A DC short circuit protection device according to one aspect of the present disclosure includes a fuse having a bus bar and cutting off the bus bar in response to an ignition signal, a first current detection unit having a first resistor and detecting a current flowing through the bus bar, and a second current detection unit having a second resistor and detecting a current flowing through the bus bar, wherein the first resistor and the second resistor are integrated with the bus bar so that a current of the same magnitude as the current flowing through the bus bar flows, and wherein the bus bar is cut off between the first current detection unit and the second current detection unit in response to the ignition signal, or the first resistor of the first current detection unit is cut off.

[0007] According to the DC short circuit protection device according to one aspect of the present disclosure, heat can be easily dissipated.

[0008] FIG. 1 is a configuration diagram showing an example of a DC short circuit protection device according to an embodiment; FIG. 2 is a perspective view of an active-type fuse in a first example; FIG. 3 is a partial cross-sectional view of an active-type fuse in a first example; FIG. 4 is a perspective view of an active-type fuse in a second example; FIG. 5 is a partial cross-sectional view of an active-type fuse in a third example; FIG. 6 is a partial cross-sectional view of an active-type fuse in a fourth example; FIG. 7 is a bottom view of a bus bar in a fourth example; FIG. 8 is a diagram for explaining the cross-sectional structure of a bus bar in a fourth example; and FIG. 9 is a top view of a bus bar in a fifth example.

[0009] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0010] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0011] (Embodiment) A DC short circuit protection device 1 according to an embodiment will be described with reference to FIG.

[0012] FIG. 1 is a configuration diagram showing an example of a DC short circuit protection device 1 according to an embodiment.

[0013] The DC short circuit protection device 1 is mounted on a vehicle such as an electric vehicle that uses electric power for propulsion. A high-voltage battery is mounted on the electric vehicle, and power is supplied from the battery to a load such as a motor, thereby propelling the vehicle. In the event of an accident or the like, a large current due to a short circuit may flow in the path connecting the battery and the load, which may cause the battery to smoke or catch fire. Therefore, the DC short circuit protection device 1 is provided to interrupt this path.

[0014] The DC short circuit protection device 1 includes an active type fuse 10 and a trip control circuit 20 .

[0015] The active-type fuse 10 is a device, such as a pyroelectric fuse, that cuts off a path connecting a battery and a load when a large current flows through the path due to a short circuit. A pyroelectric fuse contains an explosive and ignites the explosive based on an external control signal. The explosive ignition generates an explosive force that irreversibly cuts off a bus bar, thereby interrupting the current. The active-type fuse 10 includes a cutter 11, a bus bar 12, and multiple current detection units. While two current detection units 13a and 13b are shown as the multiple current detection units here, the number of multiple current detection units may be three or more. Note that if the number of current detection units is large, the detection signal from each current detection unit must be processed, which increases the processing load. For this reason, this specification describes an example in which the number of multiple current detection units is two or three, rather than four or more.

[0016] The bus bar 12 is a long conductive rod that is connected (e.g., fastened) to a path connecting a battery and a load and becomes part of the path. The cutter 11 cuts the bus bar 12 in response to an ignition signal from the interruption control circuit 20. Because the bus bar 12 is part of the path, cutting the bus bar 12 can interrupt the path.

[0017] FIG. 2 is a perspective view of an example of an active-type fuse 10. As shown in FIG. 2, the current detection unit 13a has a resistor 131a, and the current detection unit 13b has a resistor 131b. Each of the current detection units 13a and 13b is a current sensor that detects the current flowing through the bus bar 12. The resistors 131a and 131b are integrated with the bus bar 12 so that a current of the same magnitude as the current flowing through the bus bar 12 flows through the resistors 131a and 131b. An example of integration will be described later. The current detection units 13a and 13b detect the current flowing through the bus bar 12 by converting the current flowing through the resistors 131a and 131b, respectively, into a voltage. The multiple current detection units are distributed and arranged at one end and the other end of the bus bar 12 in the longitudinal direction. An example of a distributed arrangement will be described later.

[0018] The shutoff control circuit 20 is connected to the active-type fuse 10 and controls the active-type fuse 10 to cut off the bus bar 12. Specifically, the shutoff control circuit 20 outputs an ignition signal S3 to the active-type fuse 10 based on a detection signal S1 output from the current detection unit 13a and a detection signal S2 output from the current detection unit 13b. When the ignition signal S3 is input, the cutter 11 cuts off the bus bar 12. The shutoff control circuit 20 is realized by, for example, a microcontroller unit (MCU). The shutoff control circuit 20 includes a detection signal acquisition unit 21, a shutoff determination unit 22, a comparison unit 23, and an ignition control circuit 24.

[0019] The detection signal acquiring unit 21 acquires a detection signal S1 output from the current detecting unit 13 a and a detection signal S2 output from the current detecting unit 13 b. For example, the detection signal S1 is a signal indicating a voltage generated when a current flows through the resistor 131 a of the current detecting unit 13 a, and the detection signal S2 is a signal indicating a voltage generated when a current flows through the resistor 131 b of the current detecting unit 13 b.

[0020] The interruption determination unit 22 determines whether to interrupt the path connecting the battery and the load based on the detection signals S1 and S2 output from the current detection units 13 a and 13 b. For example, the interruption determination unit 22 first calculates the value of the current flowing through the busbar 12 by dividing the sum of the voltage indicated by the detection signal S1 output from the current detection unit 13 a and the voltage indicated by the detection signal S2 output from the current detection unit 13 b by the sum of the resistance values ​​of the resistor units 131 a and 131 b. Next, if the calculated value of the current flowing through the busbar 12 is equal to or greater than a predetermined value, that is, if a large current is flowing through the busbar 12, the interruption determination unit 22 determines to interrupt the path.

[0021] The comparison unit 23 compares the current value calculated based on the detection signal S1 with the current value calculated based on the detection signal S2. Specifically, the comparison unit 23 calculates multiple current values ​​by dividing the voltage indicated by the detection signal S1 by the resistance value of the resistor unit 131a, and further dividing the voltage indicated by the detection signal S2 by the resistance value of the resistor unit 131b. The comparison unit 23 performs failure detection for the current detection units 13a and 13b based on the comparison result of the multiple current values. If the multiple current values ​​differ, the comparison unit 23 determines that either the current detection unit 13a or the current detection unit 13b has failed. For example, if any of the multiple current detection units has failed, the shutdown control circuit 20 may notify an external device of this fact.

[0022] When it is determined that the path connecting the battery and the load should be cut off, the ignition control circuit 24 outputs an ignition signal S3 to the active-type fuse 10. As a result, when a large current flows in the path due to a short circuit, the active-type fuse 10 cuts off the bus bar 12, thereby cutting off the path.

[0023] The DC short circuit protection device 1 has various configurations, and the following will explain first to fifth examples.

[0024] (First Example) First, a first example of the DC short circuit protective device 1 will be described with reference to Figs.

[0025] FIG. 2 is a perspective view of an active-type fuse 10 according to a first example.

[0026] 3 is a partial cross-sectional view of the active-type fuse 10 according to the first embodiment. In FIG. 3, the cross section of the cutting machine 11 is omitted.

[0027] The cutter 11 has, for example, an ignition terminal 11a and a cutting blade 11b. The ignition terminal 11a is connected to an ignition control circuit 24 of the shutoff control circuit 20. When an ignition signal S3 (see FIG. 1) is output from the ignition control circuit 24 to the ignition terminal 11a, the cutter 11 momentarily pushes the cutting blade 11b downward to cut the bus bar 12.

[0028] For example, busbar 12 has fastening portion 12a at one longitudinal end thereof and fastening portion 12b at the other longitudinal end thereof. Busbar 12 is inserted into the middle of a path connecting a battery and a load, and fastening portions 12a and 12b are fastened to the path with screws or the like. This makes busbar 12 part of the path. Cutting portion 121 of busbar 12 is the portion that is cut by cutting blade 11b of cutter 11 when ignition signal S3 is output from shutoff control circuit 20.

[0029] In the first example, the multiple current detection units are distributed and arranged at one end side (e.g., the fastening portion 12a side) and the other end side (e.g., the fastening portion 12b side) in the longitudinal direction of the bus bar 12 with respect to the cut portion 121 of the bus bar 12 that is cut by the active-type fuse 10. Also, in the first example, there are two multiple current detection units, and one of the two current detection units, current detection unit 13a, is arranged at one end side in the longitudinal direction of the bus bar 12 with respect to the cut portion 121, and the other current detection unit 13b is arranged at the other end side in the longitudinal direction of the bus bar 12 with respect to the cut portion 121.

[0030] The current detection unit 13a includes a resistor 131a, and the current detection unit 13b includes a resistor 131b. For example, the resistance value of the resistor 131a and the resistance value of the resistor 131b are the same. Each of the resistors 131a and 131b is a resistive element (shunt resistor) of approximately several tens of microohms. As shown in FIGS. 2 and 3 , the resistors 131a and 131b are integrated with the busbar 12 by being inserted into the busbar 12. Note that in the fourth and fifth examples described below, the resistors 131a and 131b are not resistive elements but are part of the busbar 12, and are integrated with the busbar 12 as part of the busbar 12. The resistors 131a and 131b integrated with the busbar 12 convert the current flowing through the busbar 12 into a voltage, thereby enabling the current flowing through the busbar 12 to be detected.

[0031] For example, each of the multiple current detection units has two current monitoring terminals for monitoring the current flowing through the resistor unit. In a first example, the current detection unit 13a has current monitoring terminals 132a and 133a for monitoring the current flowing through the resistor unit 131a, and the current monitoring terminals 132a and 133a are provided on the bus bar 12 so that the resistor unit 131a is located between the current monitoring terminals 132a and 133a. The current detection unit 13b has current monitoring terminals 132b and 133b for monitoring the current flowing through the resistor unit 131b, and the current monitoring terminals 132b and 133b are provided on the bus bar 12 so that the resistor unit 131b is located between the current monitoring terminals 132b and 133b. For example, the distance between the current monitoring terminals 132a and 133a is approximately the same as the distance between the current monitoring terminals 132b and 133b.

[0032] The current monitoring terminals 132a, 133a, 132b, and 133b are connected to the detection signal acquiring unit 21 of the shutoff control circuit 20. The detection signal acquiring unit 21 acquires, as detection signals, the voltage between the current monitoring terminals 132a and 133a, i.e., the voltage generated in the resistor 131a when a current flows through the resistor 131a, and the voltage between the current monitoring terminals 132b and 133b, i.e., the voltage generated in the resistor 131b when a current flows through the resistor 131b.

[0033] In the first example, multiple current detection units are provided outside the housing of the active type fuse 10, but at least one of the multiple current detection units may be provided inside the housing of the active type fuse 10.

[0034] Furthermore, the cutter 11 may have a plurality of cutting blades, and when the ignition signal S3 is output from the cutoff control circuit 20, the bus bar 12 may be cut at a plurality of locations.

[0035] As described above, the DC short circuit protection device 1 includes the active-type fuse 10 having the bus bar 12 and disconnecting the bus bar 12 in response to the ignition signal S3 (see FIG. 1), the current detection unit 13a having the resistor 131a and detecting the current flowing through the bus bar 12, and the current detection unit 13b having the resistor 131b and detecting the current flowing through the bus bar 12, and the resistors 131a and 131b are integrated with the bus bar 12 so that a current of the same magnitude as the current flowing through the bus bar 12 flows between the resistors 131a and 131b, and is disconnected between the current detection units 13a and 13b. In other words, the current detection units 13a and 13b are provided separately on the bus bar.

[0036] For example, if multiple current detection units are not distributed and only one current detection unit is disposed, a resistor with a certain resistance value is required to detect the current, and heat is concentrated in the resistor of one current detection unit, making heat dissipation difficult. On the other hand, if multiple current detection units are distributed, the resistance value per resistor can be reduced, which reduces the heat generated by each resistor and alleviates the concentration of heat. Therefore, a DC short-circuit protection device 1 in which multiple current detection units are distributed can easily dissipate heat.

[0037] For example, it is preferable that the multiple current detection units are distributed and arranged at one end and the other end in the longitudinal direction of the busbar 12 with respect to the cut portion 121 of the busbar 12 that is cut by the active-type fuse 10. For example, there may be two current detection units, and one of the two current detection units, current detection unit 13a, may be arranged at one end in the longitudinal direction of the busbar 12 with respect to the cut portion 121, and the other current detection unit 13b may be arranged at the other end in the longitudinal direction of the busbar 12 with respect to the cut portion 121.

[0038] For example, if there are a large number of current detection units, it is necessary to process the detection signals of each of the multiple current detection units, which increases the processing load.In contrast, by reducing the number of multiple current detection units to two and distributing the two current detection units, it is possible to reduce the processing load and easily dissipate heat.

[0039] For example, the DC short circuit protection device 1 may further include a shutoff control circuit 20 that outputs an ignition signal S3 to the active-type fuse 10 based on detection signals output from a plurality of current detection sections.

[0040] In this way, the shutdown control circuit 20 may be provided in the DC short circuit protection device 1 .

[0041] For example, each of the plurality of current detection units may have a current monitoring terminal for monitoring the current flowing through the resistance unit.

[0042] In this way, the current monitoring terminal may be provided in the current detection unit.

[0043] For example, the DC short circuit protection device 1 may further include a comparison unit 23 that compares multiple current values ​​based on detection signals output from multiple current detection units, and the comparison unit 23 may detect faults in the multiple current detection units based on the comparison results of the multiple current values.

[0044] According to this, since the same amount of current flows through the resistor portion of each of the multiple current detection portions, the multiple current values ​​based on the detection signals output from the multiple current detection portions should be the same, but if one of the multiple current detection portions is faulty, the current values ​​may be different. For example, if there are two multiple current detection portions and the two current values ​​are different, it is difficult to identify which of the two current detection portions is faulty, but it is possible to detect that one of the two current detection portions is faulty.

[0045] Second Example Next, a second example of the DC short circuit protective device 1 will be described with reference to FIG.

[0046] FIG. 4 is a perspective view of an active-type fuse 10 according to the second embodiment.

[0047] In the second example, the bus bar 12 is provided with a temperature monitor terminal 140 for monitoring the temperature of the bus bar 12. Other points are the same as those in the first example, and therefore description thereof will be omitted.

[0048] A thermistor, a thermocouple, or the like is connected to the temperature monitor terminal 140 to monitor the temperature of the bus bar 12. The temperature of the bus bar 12 is acquired by the shutdown control circuit 20 and is used by the shutdown determination unit 22 to calculate the current value of the current flowing through the bus bar 12.

[0049] The resistance values ​​of the resistors included in the multiple current detection units change with temperature, which in turn changes the voltage generated in the resistors. As a result, the calculation result of the current flowing through the busbar 12 changes with temperature. Therefore, the temperature of the busbar 12, into which the resistors are integrated, is monitored, and the detection signals or calculated current values ​​of the multiple current detection units are corrected according to the temperature of the busbar 12, thereby enabling accurate detection of the current flowing through the busbar 12.

[0050] (Third Example) Next, a third example of the DC short circuit protective device 1 will be described with reference to FIG.

[0051] Fig. 5 is a partial cross-sectional view of an active-type fuse 10 according to a third embodiment. The cross section of the cutter 11 is omitted from Fig. 5. The current monitor terminal is also omitted from Fig. 5.

[0052] In the third example, there are three current detection units, and two of the three current detection units 13a to 13c, namely, current detection units 13a and 13c (resistance units 131a and 131c), are arranged on one end side in the longitudinal direction of the busbar 12 with respect to the cut portion 121, and the remaining one of the three current detection units 13a to 13c, namely, current detection unit 13b (resistance unit 131b), is arranged on the other end side in the longitudinal direction of the busbar 12 with respect to the cut portion 121. Other points are the same as in the first example, and therefore description thereof will be omitted.

[0053] In the third example, by setting the number of current detection units to three, it is possible to identify a faulty current detection unit among the multiple current detection units. Specifically, if the current value based on the detection signal output from one of the three current detection units 13 a to 13 c is different from the two current values ​​based on the detection signals output from the other two current detection units, it is possible to detect that the one current detection unit has failed.

[0054] Figure 5 shows an example in which the current detection unit 13c is provided inside the housing of the active type fuse 10, but two or more of the three current detection units 13a to 13c may be provided inside the housing of the active type fuse 10, or all three current detection units 13a to 13c may be provided outside the housing of the active type fuse 10.

[0055] In the third example, the temperature monitor terminal 140 may also be provided on the bus bar 12 .

[0056] (Fourth Example) Next, a fourth example of the DC short circuit protective device 1 will be described with reference to Figs. 6 to 8 .

[0057] 6 is a partial cross-sectional view of an active-type fuse 10 according to a fourth embodiment. In FIG. 6, the cross section of the cutting machine 11 is omitted.

[0058] FIG. 7 is a bottom view of the bus bar 12 in the fourth example.

[0059] 8 is a diagram for explaining the cross-sectional structure of the bus bar 12 in the fourth example, in which the current monitor terminals are omitted.

[0060] In a fourth example, each resistive portion of the multiple current detection units (resistive portions 131a and 131b of two current detection units in the fourth example) is a part of the busbar 12, and the portion of the busbar 12 with a higher resistance value due to being narrowed or thinned is utilized as the resistive portion. Specifically, the cross-sectional area of ​​the resistive portion of the busbar 12, perpendicular to the direction of current flow, is smaller than the cross-sectional area of ​​the portion of the busbar 12 other than the resistive portion, perpendicular to the direction of current flow. As shown in FIGS. 7 and 8 , it can be seen that the cross-sectional area of ​​the resistive portion 131a (the area of ​​the B-B' cross section in FIG. 8 ) is smaller than the cross-sectional area of ​​the portion other than the resistive portions 131a and 131b (for example, the areas of the A-A' cross section and the C-C' cross section in FIG. 8 ). Current monitor terminals are connected to both ends of the portion with the smaller cross-sectional area, and the voltage generated by the current flowing through the portion can be acquired via the current monitor terminals, thereby utilizing the portion as a current detection unit.

[0061] In the fourth example, the active-type fuse 10 cuts the bus bar 12 at two locations, one end and the other end, in the longitudinal direction of the bus bar 12. For example, the cutter 11 of the active-type fuse 10 has two cutting blades 11c and 11d. When the ignition signal S3 is output from the ignition control circuit 24 to the ignition terminal 11a, the cutter 11 instantly pushes the cutting blades 11c and 11d downward in FIG. 6 to cut the bus bar 12. Furthermore, the resistor 131a included in one current detection unit 13a among the multiple current detection units is the cut portion at one end in the longitudinal direction of the bus bar 12 that is cut by the active-type fuse 10, and the resistor 131b included in the other current detection unit 13b among the multiple current detection units is the cut portion at the other end in the longitudinal direction of the bus bar 12 that is cut by the active-type fuse 10. In other words, the resistance portion 131a is the cut portion at one end in the longitudinal direction of the bus bar 12 that is cut by the cutting blade 11c of the cutting machine 11 when the ignition signal S3 is output from the cutting control circuit 20, and the resistance portion 131b is the cut portion at the other end in the longitudinal direction of the bus bar 12 that is cut by the cutting blade 11d of the cutting machine 11 when the ignition signal S3 is output from the cutting control circuit 20.

[0062] To facilitate cutting, the cut portion of the busbar 12 that is cut by the active-type fuse 10 has a smaller cross-sectional area (e.g., is constricted) than the other portions of the busbar 12. This gives the cut portion of the busbar 12 a higher resistance value than the other portions of the busbar 12. Therefore, the cut portion can be used as a resistor for detecting the current flowing through the busbar 12, which simplifies the structure of the DC short-circuit protection device 1 and reduces costs compared to when a separate resistor for detecting the current flowing through the busbar 12 is provided.

[0063] When the cut portion of the bus bar 12 is treated as a resistance portion, the resistance value varies due to dimensional tolerances resulting from the processing accuracy of the cut portion, etc. For this reason, a calibration value for each individual bus bar may be stored in a flash memory or the like of the shutoff control circuit 20, and the current value may be corrected for each individual bus bar using the calibration value.

[0064] In the fourth example, the number of the current detection units may be three or more. The current detection units may include a mixture of current detection units in which the resistance unit is a part of the bus bar 12 and current detection units in which the resistance unit is a resistive element.

[0065] In addition, in the fourth example, the cut portion of the busbar 12 is used as the resistance portion of the current detection unit, but a portion that is not the cut portion and has a smaller cross-sectional area may also be used as the resistance portion of the current detection unit.

[0066] In the fourth example, the temperature monitor terminal 140 may also be provided on the bus bar 12 .

[0067] (Fifth Example) Next, a fifth example of the DC short circuit protective device 1 will be described with reference to FIG.

[0068] Fig. 9 is a top view of the bus bar 12 in the fifth example. Note that current monitor terminals are not shown in Fig. 9.

[0069] In the fifth example, the shape of the resistor portion (cut portion) of the bus bar is different from that of the fourth example, but other points are the same as those of the fourth example, and therefore description thereof will be omitted.

[0070] If the cut portion of the busbar 12 is treated as a resistance portion, the resistance value of the resistance portion will vary depending on factors such as the dimensional tolerance of the cut portion. However, as shown in FIG. 9 , by forming the resistance portion (cut portion) so that its cross-sectional shape is constant for approximately several millimeters along the direction of current flow, it is possible to stably detect the current even if there is variation in the resistance value due to processing accuracy.

[0071] (Other Embodiments) As described above, the embodiments have been described as examples of the technology according to the present disclosure. However, the technology according to the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. For example, the following modifications are also included in one embodiment of the present disclosure.

[0072] For example, in the above embodiment, an example has been described in which the DC short circuit protection device 1 (specifically, the shutdown control circuit 20) is equipped with the comparison unit 23, but the DC short circuit protection device 1 does not have to be equipped with the comparison unit 23.

[0073] For example, in the above embodiment, an example has been described in which the DC short circuit protective device 1 includes the shutdown control circuit 20, but the shutdown control circuit 20 does not have to be included in the DC short circuit protective device 1. In other words, the shutdown control circuit 20 may be provided separately from the DC short circuit protective device 1.

[0074] For example, in the above embodiment, an example has been described in which each of the plurality of current detection units has a current monitoring terminal, but the current monitoring terminal does not have to be a component of the current detection unit.

[0075] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present disclosure.

[0076] (Summary) The DC short circuit protection device 1 according to the first aspect of the present disclosure includes an active-type fuse 10 having a bus bar 12 and disconnecting the bus bar 12 in response to an ignition signal S3, a current detection unit 13a having a resistance portion 131a and detecting a current flowing through the bus bar 12, and a current detection unit 13b having a resistance portion 131b and detecting a current flowing through the bus bar 12, the resistance portions 131a and 131b being integrated with the bus bar 12 so that a current of the same magnitude as the current flowing through the bus bar 12 flows, and the bus bar 12 is disconnected between the current detection units 13a and 13b in response to the ignition signal S3, or the resistance portion 131a of the current detection unit 13a is disconnected.

[0077] According to the above configuration, since a plurality of current detection portions are provided on the bus bar 12, the resistance value per resistor portion can be reduced, and heat can be easily dissipated.

[0078] In the DC short circuit protection device 1 according to the second aspect of the present disclosure, the resistance portion 131a and the resistance portion 131b are part of the bus bar 12, the direction of the current flowing through the resistance portion 131a and the bus bar 12 is a first direction (the left-right direction in this embodiment), and the cross-sectional area of ​​the resistance portion 131a perpendicular to the first direction (for example, the area of ​​the B-B' cross section shown in FIG. 8) and the cross-sectional area of ​​the resistance portion 131b perpendicular to the first direction (for example, the area of ​​the D-D' cross section shown in FIG. 8) are smaller than the cross-sectional area of ​​the portion of the bus bar 12 perpendicular to the first direction other than the resistance portion 131a and the resistance portion 131b (for example, the area of ​​the A-A' cross section shown in FIG. 8).

[0079] According to the above configuration, current monitoring terminals are connected to both ends of the portion with a reduced cross-sectional area, and the voltage generated by the current flowing through the portion can be obtained via the current monitoring terminals, making it possible to use the portion as a current detection unit.

[0080] In the DC short circuit protection device 1 according to the third aspect of the present disclosure, the busbar 12 has a cut portion 121 that is cut by the active type fuse 10, the current detection unit 13a is located between one end of the busbar 12 and the cut portion 121, and the current detection unit 13b is located between the other end of the busbar 12 and the cut portion 121.

[0081] According to the above configuration, by distributing the two current detection units, it is possible to reduce the processing load and easily dissipate heat.

[0082] The DC short circuit protection device 1 according to the fourth aspect of the present disclosure further includes a current detection unit 13 c , which is located between one end of the bus bar 12 and the cut portion 121 .

[0083] According to the above configuration, if the current value based on the detection signal output from one of the three current detection units 13a to 13c becomes a value different from the two current values ​​based on the detection signals output from the other two current detection units, it can be detected that the one current detection unit is faulty.

[0084] In the DC short circuit protection device 1 according to the fifth aspect of the present disclosure, the active-type fuse 10 cuts off the resistor 131a of the current detection unit 13a (or the resistor 131b of the current detection unit 13b) in response to the ignition signal S3.

[0085] According to the above configuration, the resistance portion 131 a (or the resistance portion 131 b ) can be utilized as the cut portion 121 .

[0086] The DC short circuit protection device 1 according to the sixth aspect of the present disclosure further includes a cutoff control circuit 20 that outputs an ignition signal S3 to the active type fuse 10 in response to the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b.

[0087] According to the above configuration, the bus bar 12 can be interrupted in response to the detection signals S1 and S2 output from the current detection units 13a and 13b.

[0088] In the DC short circuit protection device 1 according to the seventh aspect of the present disclosure, the current detection unit 13a has current monitoring terminals 132a and 133a for monitoring the current flowing through the resistance unit 131a, and the current detection unit 13b has second current monitoring terminals 132b and 133b for monitoring the current flowing through the resistance unit 131b.

[0089] According to the above configuration, the voltages generated in the resistors 131a and 131b can be output as detection signals S1 and S2 from the current detection units 13a and 13b.

[0090] The DC short circuit protection device 1 according to the eighth aspect of the present disclosure further includes a temperature monitor terminal 140 that is provided on the bus bar 12 and monitors the temperature of the bus bar 12 .

[0091] According to the above configuration, the temperature of the bus bar 12 can be monitored, and the temperature of the bus bar 12 can be used to calculate the current value.

[0092] The DC short circuit protection device 1 according to the ninth aspect of the present disclosure further includes a comparison unit 23 that compares a first current value calculated based on the detection signal S1 output from the current detection unit 13a with a second current value calculated based on the detection signal S2 output from the current detection unit 13b.

[0093] According to the above configuration, if the first current value and the second current value are different, it can be determined that either the current detection unit 13a or the current detection unit 13b has failed.

[0094] The present disclosure is applicable to a device that interrupts a current flowing in a current path.

[0095] REFERENCE SIGNS LIST 1 DC short circuit protection device 10 Active type fuse 11 Cutting machine 11a Ignition terminal 11b, 11c, 11d Cutting blade 12 Bus bar 12a, 12b Fastening portion 13a, 13b, 13c Current detection portion 20 Shutdown control circuit 21 Detection signal acquisition portion 22 Shutdown determination portion 23 Comparison portion 24 Ignition control circuit 121 Cutting portion 131a, 131b, 131c Resistance portion 132a, 133a, 132b, 133b Current monitor terminal 140 Temperature monitor terminal S1, S2 Detection signal S3 Ignition signal

Claims

1. a fuse having a bus bar and cutting the bus bar in response to an ignition signal; a first current detection unit having a first resistance portion and detecting a current flowing through the bus bar; a second current detection unit having a second resistance unit and detecting a current flowing through the bus bar; Equipped with the first resistance portion and the second resistance portion are integrated with the bus bar so that a current having the same magnitude as a current flowing through the bus bar flows through the first resistance portion and the second resistance portion; The bus bar is disconnected between the first current detection unit and the second current detection unit in response to the ignition signal, or the first resistance unit of the first current detection unit is disconnected. DC short circuit protection device.

2. the first resistor portion and the second resistor portion are part of the bus bar, a direction of a current flowing through the first resistor portion, the second resistor portion, and the bus bar is defined as a first direction; a cross-sectional area of ​​the first resistor portion perpendicular to the first direction and a cross-sectional area of ​​the second resistor portion perpendicular to the first direction are smaller than a cross-sectional area of ​​a portion of the bus bar perpendicular to the first direction other than the first resistor portion and the second resistor portion.

2. The DC short circuit protection device according to claim 1.

3. the bus bar has a cut portion that is cut by the fuse, the first current detection unit is located between one end of the bus bar and the cut portion, The second current detection unit is located between the other end of the bus bar and the cut portion.

2. The DC short circuit protection device according to claim 1.

4. Further comprising a third current detection unit, The third current detection unit is located between the one end and the cut portion of the bus bar.

4. The DC short circuit protection device according to claim 3.

5. The fuse disconnects the first resistor of the first current detection unit in response to the ignition signal.

3. The DC short circuit protection device according to claim 2.

6. The fuse may be connected to the power supply of the power source in response to a signal output from the first current detection unit and a signal output from the second current detection unit. The DC short circuit protection device according to any one of claims 1 to 5.

7. the first current detection unit has a first current monitor terminal for monitoring a current flowing through the first resistance unit, the second current detection unit has a second current monitor terminal for monitoring a current flowing through the second resistance unit; The DC short circuit protection device according to any one of claims 1 to 5.

8. The electric power supply further includes a temperature monitor terminal provided on the bus bar and configured to monitor a temperature of the bus bar. The DC short circuit protection device according to any one of claims 1 to 5.

9. The power supply circuit further includes a comparison unit that compares a first current value calculated based on a first detection signal output from the first current detection unit with a second current value calculated based on a second signal output from the second current detection unit. The DC short circuit protection device according to any one of claims 1 to 5.