DC short circuit protection device

Abstract

A DC short circuit protection device (1) comprises: a fuse (10) that includes a bus bar (12) and disconnects the bus bar in response to an ignition signal (S3); a first current detection unit (13a) that includes a first resistor unit (131a) and detects a current flowing through the bus bar; a second current detection unit (13b) that includes a second resistor unit (131b) and detects a current flowing through the bus bar; and a shutdown control circuit (20) that outputs the ignition signal to the fuse on the basis of a first detection signal (S1) output from the first current detection unit and a second detection signal (S2) output from the second current detection unit. The first resistor unit and the second resistor unit are integrated with the bus bar such that a current of the same magnitude as the current flowing through the bus bar flows therethrough. A resistance value of the first resistor unit and a resistance value of the second resistor unit are different.

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, in the electrical circuit breaker described in Patent Document 1, if there is a large change in the current flowing due to noise or the like, a back electromotive force (V = -L × di / dt) is generated due to the influence of the inductance component in the current detection sensor (shunt resistor). This back electromotive force may cause the current value to be detected as being higher than it actually is, which could result in a false break.

[0005] Therefore, the present disclosure provides a DC short circuit protection device that can suppress erroneous tripping due to the influence of inductance components.

[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 resistance element and detecting a current flowing through the bus bar; a second current detection unit having a second resistance element and detecting a current flowing through the bus bar; and a shutoff control circuit that outputs the ignition signal to the fuse based on a first detection signal output from the first current detection unit and the second detection signal output from the second current detection unit, wherein the first resistance element and the second resistance element are integrated with the bus bar so that a current of the same magnitude as the current flowing through the bus bar flows, and the resistance values ​​of the first resistance element and the second resistance element are different from each other.

[0007] According to the DC short circuit protection device according to one aspect of the present disclosure, it is possible to suppress erroneous tripping due to the influence of inductance components.

[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 the active-type fuse 10. As shown in FIG. 2, the current detection unit 13a has a resistor 131a and is a current sensor that detects the current flowing through the bus bar 12. The current detection unit 13a is an example of a first current detection unit. The resistor 131a is an example of a first resistor unit. The current detection unit 13b has a resistor 131b and is a current sensor that detects the current flowing through the bus bar 12. The current detection unit 13b is an example of a second current detection unit. The resistor 131b is an example of a second resistor unit. 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. An example of integration will be described later. The current detection unit 13a detects the current flowing through the bus bar 12 by converting the current flowing through the resistor 131a into a voltage. The current detection unit 13b detects the current flowing through the bus bar 12 by converting the current flowing through the resistance unit 131b into a voltage.

[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 or not to interrupt the path connecting the battery and the load based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. For example, the interruption determination unit 22 determines whether or not to disconnect the busbar 12 by performing a predetermined calculation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. The predetermined calculation will be described in detail later.

[0021] The comparator 23 compares a first current value calculated based on the detection signal S1 output from the current detector 13a with a second current value calculated based on the detection signal S2 output from the current detector 13b. Specifically, the comparator 23 calculates the first current value by dividing the voltage indicated by the detection signal S1 output from the current detector 13a by the resistance value of the resistor 131a, and calculates the second current value by dividing the voltage indicated by the detection signal S2 output from the current detector 13b by the resistance value of the resistor 131b. The comparator 23 detects a fault in the current detectors 13a and 13b based on the comparison result between the first current value and the second current value. For example, if the first current value and the second current value are different, the comparator 23 determines that one of the current detectors 13a and 13b has a fault. For example, if either of the current detection units 13a and 13b has failed, the cutoff control circuit 20 may notify an external device of this fact.

[0022] When the cutoff determination unit 22 determines that cutting the bus bar 12 is executable, 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 above-mentioned path due to a short circuit abnormality, the active-type fuse 10 cuts the bus bar 12, thereby cutting the above-mentioned 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 instantly 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 present disclosure, the resistance value of the resistor 131a included in the current detection unit 13a is different from the resistance value of the resistor 131b included in the current detection unit 13b. For example, the resistors 131a and 131b are resistive elements (shunt resistors) 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.

[0030] In the first example, the current detection unit 13a has two current monitor terminals 132a and 133a for monitoring the current flowing through the resistor unit 131a, and the current monitor terminals 132a and 133a are provided on the bus bar 12 so that the resistor unit 131a is located between the current monitor terminals 132a and 133a. The current detection unit 13b has two current monitor terminals 132b and 133b for monitoring the current flowing through the resistor unit 131b, and the current monitor terminals 132b and 133b are provided on the bus bar 12 so that the resistor unit 131b is located between the current monitor terminals 132b and 133b. For example, the distance between the current monitor terminals 132a and 133a and the distance between the current monitor terminals 132b and 133b are approximately the same. In other words, the inductance component between the current monitor terminals 132a and 133a is substantially the same as the inductance component between the current monitor terminals 132b and 133b.

[0031] 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.

[0032] As described above, the shutdown control circuit 20 determines whether or not to disconnect the busbar 12 by performing a predetermined calculation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b. The predetermined calculation includes dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor 131a included in the current detection unit 13a and the resistance value of the resistor 131b included in the current detection unit 13b. As will be described in detail later, by performing such a calculation on the detection signals S1 and S2 output from the current detection units 13a and 13b, respectively, which have resistors 131a and 131b with different resistance values, it is possible to detect the current flowing through the busbar 12 while suppressing false disconnections due to the influence of inductance components.

[0033] If the current value based on the result of the predetermined calculation is equal to or greater than a predetermined value, that is, if a large current is flowing through the bus bar 12, the interruption determination unit 22 determines to interrupt the path.

[0034] In the first example, the current detection units 13a and 13b are provided outside the housing of the active type fuse 10, but at least one of the current detection units 13a and 13b may be provided inside the housing of the active type fuse 10.

[0035] 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.

[0036] As described above, the DC short circuit protection device 1 comprises: an active-type fuse 10 having a bus bar 12 and cutting off the bus bar 12 in response to an ignition signal S3 (see FIG. 1 ); a current detection unit 13a having a resistance portion 131a and detecting the current flowing through the bus bar 12; a current detection unit 13b having a resistance portion 131b and detecting the current flowing through the bus bar 12; and a shutoff control circuit 20 that outputs the ignition signal S3 to the active-type fuse 10 based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, and the resistance portions 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 them, and the resistance values ​​of the resistance portions 131a and 131b are different from each other.

[0037] When there is a large change in the current flowing through the busbar 12 due to noise or sudden vehicle acceleration (i.e., when di / dt is large), a large back electromotive force (V = -L × di / dt) is generated in the resistors 131a and 131b due to the influence of their respective inductance components (L). The detection signals S1 and S2 output from the current detectors 13a and 13b contain such a large back electromotive force component. This back electromotive force may cause the current value to be detected as higher than it actually is, potentially resulting in a false interruption. However, the resistance values ​​and inductance components of the resistors 131a and 131b do not correspond to each other, and the back electromotive force generated in the resistors 131a and 131b are substantially the same even if the resistance values ​​of the resistors 131a and 131b are different. Therefore, in the present disclosure, the back electromotive force components included in the detection signals S1 and S2 are cancelled out by calculating the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, thereby suppressing false tripping due to the influence of the inductance component.

[0038] Note that resistors 131a and 131b, which have different resistance values, generate voltages of different magnitudes depending on their respective resistance values ​​when a current flows through busbar 12. Therefore, when taking the difference between detection signal S1 output from current detection unit 13a and detection signal S2 output from current detection unit 13b, it is possible to retain the voltage component generated by the current flowing through busbar 12. Therefore, it is possible to detect the current flowing through busbar 12 while suppressing false interruptions due to the influence of inductance components.

[0039] For example, the cutoff control circuit 20 may determine whether or not to cut the bus bar 12 by performing a predetermined calculation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, and if it determines that cutting the bus bar 12 is possible, it may output an ignition signal to the active-type fuse 10. For example, the predetermined calculation may include a calculation of dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor unit 131a and the resistance value of the resistor unit 131b.

[0040] According to this, the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b includes the difference between the voltage generated across the resistor portion 131a and the voltage generated across the resistor portion 131b due to the current flowing through the busbar 12. The difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b is a voltage corresponding to the difference between the resistance value of the resistor portion 131a and the resistance value of the resistor portion 131b, so the current flowing through the busbar 12 can be detected by dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor portion 131a and the resistance value of the resistor portion 131b.

[0041] For example, the current detection unit 13a may have current monitor terminals 132a and 133a for monitoring the current flowing through the resistor unit 131a, and the current detection unit 13b may have current monitor terminals 132b and 133b for monitoring the current flowing through the resistor unit 131b.

[0042] In this way, the current monitoring terminals 132a, 133a, 132b, and 133b may be provided in the current detection units 13a and 13b.

[0043] For example, the DC short circuit protection device 1 may further include a comparison unit 23 that compares a first current value based on the detection signal S1 output from the current detection unit 13a with a second current value based on the detection signal S2 output from the current detection unit 13b, and the comparison unit 23 may detect a fault in the current detection unit 13a or 13b based on the comparison result between the first current value and the second current value.

[0044] According to this, since the same amount of current flows through the resistors 131a and 131b of the current detection units 13a and 13b, the first current value and the second current value based on the detection signals S1 and S2 output from the current detection units 13a and 13b should be the same, but if either of the current detection units 13a and 13b is faulty, the current values ​​may be different. Therefore, if the first current value and the second current value are different, it can be detected that either of the current detection units 13a and 13b 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 resistors 131a and 131b change with temperature, which in turn changes the voltages generated across resistors 131a and 131b. As a result, the calculation result of the current flowing through busbar 12 changes with temperature. Therefore, the temperature of busbar 12, which is integrated with resistors 131a and 131b, is monitored, and the detection signals or calculated current values ​​of current detectors 13a and 13b are corrected according to the temperature of busbar 12, thereby enabling accurate detection of the current flowing through 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, the active-type fuse 10 further includes a current detection section 13c (resistance section 131c). Since the other points are the same as those in the first example, a description thereof will be omitted.

[0053] In the third example, the active-type fuse 10 includes three current detection units 13 a to 13 c, making it possible to identify a faulty current detection unit among the three current detection units 13 a to 13 c. 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 current detection unit 13c is provided inside the housing of active type fuse 10, but two or more of the three current detection units 13a to 13c may be provided inside the housing of active type fuse 10, or all three current detection units may be provided outside the housing of 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 the fourth example, the resistor portions 131a and 131b are part of the busbar 12, and the resistor portions 131a and 131b are formed by thinning or increasing the resistance of a portion of the busbar 12. Specifically, the cross-sectional area of ​​the resistor portions 131a and 131b of the busbar 12, which is perpendicular to the direction of current flow, is smaller than the cross-sectional area of ​​the portions of the busbar 12 other than the resistor portions 131a and 131b, which is perpendicular to the direction of current flow. As shown in FIGS. 7 and 8 , the cross-sectional areas of the resistor portions 131a and 131b (the areas of the B-B' cross section and the areas of the D-D' cross section in FIG. 8 ) are smaller than the cross-sectional areas of the portions other than the resistor portions 131a and 131b (for example, the areas of the A-A' cross section and the areas of the C-C' cross section in FIG. 8 ). By connecting current monitoring terminals to both ends of the portion with a smaller cross-sectional area and making it possible to obtain the voltage generated by current flowing through that portion via the current monitoring terminals, that portion can be used as a current detection portion.

[0061] In the fourth example, the area of ​​a cross section perpendicular to the direction of current flow in resistor portion 131a of busbar 12 is different from the area of ​​a cross section perpendicular to the direction of current flow in resistor portion 131b of busbar 12. This allows the resistance values ​​of resistor portion 131a and resistor portion 131b to be different even when resistor portions 131a and 131b are part of busbar 12. For example, as shown in Figures 7 and 8, the cross-sectional area of ​​resistor portion 131a (the area of ​​the B-B' cross section in Figure 8) is smaller than the cross-sectional area of ​​resistor portion 131b (the area of ​​the D-D' cross section in Figure 8), and the resistance value of resistor portion 131a is greater than the resistance value of resistor portion 131b.

[0062] In the fourth example, the cutter 11 of the active-type fuse 10 has two cutting blades 11c and 11d, and when an 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 to cut the bus bar 12. For example, the resistance portions 131a and 131b are the cutting portions that are cut by the cutter 11.

[0063] 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., a narrowed portion) 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 the resistors 131a and 131b 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 separate resistors are provided for detecting the current flowing through the busbar 12.

[0064] When the cut portions of busbar 12 are treated as resistance portions 131a and 131b, the resistance value varies due to dimensional tolerances resulting from the processing accuracy of the cut portions, etc. For this reason, a calibration value for each individual may be stored in a flash memory or the like of shutoff control circuit 20, and the current value may be corrected for each individual using the calibration value.

[0065] In the fourth example, the active-type fuse 10 may further include a current detection unit. The two or more current detection units included in the active-type fuse 10 may include a mixture of current detection units in which the resistive unit is part of the bus bar 12 and current detection units in which the resistive unit is a resistive element.

[0066] In addition, in the fourth example, the cut portion of the busbar 12 is used as the resistance portions 131a and 131b, 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.

[0067] In the fourth example, the temperature monitor terminal 140 may also be provided on the bus bar 12 .

[0068] (Fifth Example) Next, a fifth example of the DC short circuit protective device 1 will be described with reference to FIG.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] (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.

[0073] 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.

[0074] 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.

[0075] For example, in the above embodiment, the current detection units 13a and 13b each have a current monitoring terminal, but the current monitoring terminal does not have to be a component of the current detection units 13a and 13b.

[0076] 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.

[0077] (Summary) A DC short circuit protection device 1 according to a first aspect of the present disclosure comprises 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, a current detection unit 13b having a resistance portion 131b and detecting a current flowing through the bus bar 12, and a shutoff control circuit 20 that 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, wherein the resistance portions 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 them, and the resistance value of the resistance portion 131a is different from the resistance value of the resistance portion 131b.

[0078] According to the above configuration, it is possible to suppress erroneous disconnection due to the influence of the inductance component.

[0079] In the DC short circuit protection device 1 according to the second aspect of the present disclosure, the cutoff control circuit 20 determines whether or not to cut off the bus bar 12 by performing a predetermined calculation based on the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b, and if it determines that the bus bar 12 should be cut off, it outputs an ignition signal S3 to the active type fuse 10.

[0080] According to the above configuration, it is possible to suppress erroneous disconnection due to the influence of the inductance component.

[0081] In the DC short circuit protection device 1 according to the third aspect of the present disclosure, the predetermined calculation includes a calculation of dividing the difference between the detection signal S1 output from the current detection unit 13a and the detection signal S2 output from the current detection unit 13b by the difference between the resistance value of the resistor unit 131a and the resistance value of the resistor unit 131b.

[0082] According to the above configuration, it is possible to suppress erroneous disconnection due to the influence of the inductance component.

[0083] In the DC short circuit protection device 1 according to the fourth 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, the resistance portion 131b, and the bus bar 12 is defined as a first direction, 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 areas of the portions of the bus bar 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 and the area of ​​the C-C' cross section in FIG. 8).

[0084] According to the above configuration, by connecting current monitoring terminals to both ends of the portion with a smaller cross-sectional area, the voltage generated by current flowing through the portion can be obtained via the current monitoring terminals, and the portion can be used as a current detection unit.

[0085] In the DC short circuit protection device 1 according to the fifth aspect of the present disclosure, 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) is different from 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).

[0086] According to the above configuration, by connecting current monitoring terminals to both ends of the portion with a smaller cross-sectional area, the voltage generated by current flowing through the portion can be obtained via the current monitoring terminals, and the portion can be used as a current detection unit.

[0087] In the DC short circuit protection device 1 according to the sixth 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 current monitoring terminals 132b and 133b for monitoring the current flowing through the resistance unit 131b.

[0088] According to the above configuration, the voltages generated in the resistors 131a and 131b can be output as the detection signals S1 and S2 from the current detectors 13a and 13b, respectively.

[0089] The DC short circuit protection device 1 according to the seventh aspect of the present disclosure further includes a temperature monitor terminal that is provided on the bus bar 12 and monitors the temperature of the bus bar 12 .

[0090] 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.

[0091] The DC short circuit protection device 1 according to the eighth 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 output from the current detection unit 13b, and the comparison unit 23 detects whether either the current detection unit 13a or the current detection unit 13b is faulty based on the comparison result between the first current value and the second current value.

[0092] 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.

[0093] The present disclosure is applicable to a device that interrupts a current flowing in a current path.

[0094] 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; a cutoff control circuit that outputs the ignition signal to the fuse based on a first detection signal output from the first current detection unit and a second detection signal output from the second current detection unit; Equipped with the first resistor portion and the second resistor portion are integrated with the bus bar such that a current having the same magnitude as a current flowing through the bus bar flows through the first resistor portion and the second resistor portion; The resistance value of the first resistor portion and the resistance value of the second resistor portion are different values. DC short circuit protection device.

2. the interruption control circuit determines whether to interrupt the bus bar by performing a predetermined calculation based on the first detection signal output from the first current detection unit and the second detection signal output from the second current detection unit, When it is determined that the bus bar is to be cut, the ignition signal is output to the fuse.

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

3. The predetermined calculation includes a calculation of dividing a difference between the first detection signal output from the first current detection unit and the second detection signal output from the second current detection unit by a difference between a resistance value of the first resistor unit and a resistance value of the second resistor unit.

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

4. 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.

5. The area of ​​a cross section of the first resistor portion perpendicular to the first direction is different from the area of ​​a cross section of the second resistor portion perpendicular to the first direction.

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

6. the first current detection unit has a current monitor terminal for monitoring a current flowing through the first resistance unit, The second current detection unit has a 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.

7. The temperature monitor terminal is provided on the bus bar and monitors the temperature of the bus bar. The DC short circuit protection device according to any one of claims 1 to 5.

8. a comparison unit that compares a first current value calculated based on the first detection signal output from the first current detection unit with a second current value calculated based on the second detection signal output from the second current detection unit, The comparison unit detects whether the first current detection unit or the second current detection unit is faulty based on a comparison result between the first current value and the second current value. The DC short circuit protection device according to any one of claims 1 to 5.