Short circuit protection device

Abstract

A short circuit protection device (100) comprises: a switching circuit (101) that switches between a series connection state in which a first battery module (11) and a second battery module (12) are connected in series, and a parallel connection state in which the first battery module (11) and the second battery module (12) are connected in parallel; and a first H common path (151H) that is connected to the positive electrode side of the first battery module (11), a first L common path (151L) that is connected to the negative electrode side of the first battery module (11), a second H common path (152H) that is connected to the positive electrode side of the second battery module (12), and a second L common path (152L) that is connected to the negative electrode side of the second battery module (12), the common paths being paths through which current flows in both the series connection state and the parallel connection state.

Description

Short-Circuit Protection Device

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

[0002] Electric vehicles (Battery Electric Vehicles) currently use systems with a voltage of approximately 400 to 500 V. However, in order to realize higher performance electric vehicles (for example, even faster charging), systems with even higher voltages (for example, approximately 800 to 1000 V) are required. Patent Document 1 discloses a technology that can switch between low voltage and high voltage by switching the connection state of multiple batteries between a series connection state and a parallel connection state.

[0003] Japanese Patent Application Laid-Open No. 2022-170763

[0004] However, with the technology disclosed in Patent Document 1, there are cases where the conductive path cannot be safely interrupted, such as when the relay is welded or when a short circuit occurs between the conductive paths.

[0005] Therefore, the present disclosure provides a short-circuit protection device that can safely interrupt a conductive path in a system that can switch the connection state of multiple battery modules.

[0006] A short-circuit protection device according to one aspect of the present disclosure includes a switching circuit that switches between a series connection state in which a first battery module and a second battery module are connected in series and a parallel connection state in which the first battery module and the second battery module are connected in parallel, and paths through which current flows in both the series connection state and the parallel connection state, including a first H common path connected to the positive electrode side of the first battery module, a first L common path connected to the negative electrode side of the first battery module, a second H common path connected to the positive electrode side of the second battery module, and a second L common path connected to the negative electrode side of the second battery module.

[0007] According to the short-circuit protection device according to one aspect of the present disclosure, it is possible to safely interrupt a conductive path in a system in which the connection state of a plurality of battery modules can be switched.

[0008] FIG. 1 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a first embodiment. FIG. 2 is a functional block diagram showing another example of a schematic configuration of the short-circuit protection device according to the first embodiment. FIG. 3 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a first modification of the first embodiment. FIG. 4 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a second modification of the first embodiment. FIG. 5 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a second embodiment. FIG. 6 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a third embodiment. FIG. 8 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a fourth embodiment. FIG. 9 is a functional block diagram showing an example of a schematic configuration of a shutdown control unit according to a fifth embodiment. FIG. 10 is a functional block diagram showing an example of a schematic configuration of a shutdown control unit according to a fifth embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, component placement and connection configurations, drive timing, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept of the present disclosure will be described as optional components. Furthermore, each figure is not necessarily an exact illustration. In each figure, duplicated descriptions of substantially identical configurations will be omitted or simplified.

[0010] In the following description, H means High, i.e., high voltage (for example, about 800 to 1000 V), and L means Low, i.e., low voltage (for example, about 400 to 500 V).

[0011] First Embodiment A short-circuit protection device according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG.

[0012] FIG. 1 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device according to a first embodiment.

[0013] A short-circuit protection device 100 according to an embodiment of the present disclosure is a DC short-circuit protection device for protecting a first battery module 11 and a second battery module 12 or a load 70 from a DC overcurrent caused by a short-circuit fault. The first battery module 11 and the second battery module 12 are, for example, battery modules of 400 to 500 V. The load 70 is, for example, a load in an electric vehicle, such as a motor or an inverter.

[0014] The short-circuit protection device 100 includes a first A input terminal 111, a first output terminal 121, a first B input terminal 112, a second A input terminal 113, a second output terminal 122, and a second B input terminal 114. The short-circuit protection device 100 also includes a switching circuit 101, a first fuse 21, a second fuse 22, a first current sensor 51, a second current sensor 52, a first main relay 31, a second main relay 32, a pre-charge relay 33, a pre-charge resistor 34, and a cut-off control unit 61. The short-circuit protection device 100 also includes a first H common path 151H, a first L common path 151L, a second H common path 152H, a second L common path 152L, a first conductive path 131, a second conductive path 132, a first switching path 141, a second switching path 142, and a third switching path 143. The first fuse 21 , the second fuse 22 , the first current sensor 51 , the second current sensor 52 , and the cutoff control unit 61 do not necessarily have to be components of the short-circuit protection device 100 .

[0015] The first A input terminal 111 is connected to the positive side of the first battery module 11 and is supplied with positive DC power from the first battery module 11. The first B input terminal 112 is connected to the negative side of the first battery module 11 and is supplied with negative DC power from the first battery module 11. The second A input terminal 113 is connected to the positive side of the second battery module 12 and is supplied with positive DC power from the second battery module 12. The second B input terminal 114 is connected to the negative side of the second battery module 12 and is supplied with negative DC power from the second battery module 12. The positive side of the load 70 is connected to the first output terminal 121, and the negative side of the load 70 is connected to the second output terminal 122. The first A input terminal 111 and the first output terminal 121 are connected by a first conductive path 131 , and the second B input terminal 114 and the second output terminal 122 are connected by a second conductive path 132 .

[0016] The switching circuit 101 switches between a series connection state in which the first battery module 11 and the second battery module 12 are connected in series and a parallel connection state in which the first battery module 11 and the second battery module 12 are connected in parallel. The switching circuit 101 has a first switch 41 provided on the first switching path 141, a second switch 42 provided on the second switching path 142, and a third switch 43 provided on the third switching path 143.

[0017] The first H common path 151H, the first L common path 151L, the second H common path 152H, and the second L common path 152L are paths through which current flows in both the above-described series connection state and the above-described parallel connection state. The first H common path 151H is connected to the positive electrode side of the first battery module 11, and the first L common path 151L is connected to the negative electrode side of the first battery module 11. The first H common path 151H is part of the first conductive path 131. The second H common path 152H is connected to the positive electrode side of the second battery module 12, and the second L common path 152L is connected to the negative electrode side of the second battery module 12. The second L common path 152L is part of the second conductive path 132.

[0018] The second switching path 142 is a path through which a current flows in the series connection state but not in the parallel connection state, and connects the first L common path 151L and the second H common path 152H. The first switching path 141 is a path through which a current flows in the parallel connection state but not in the series connection state, and connects the first H common path 151H and the second H common path 152H. The third switching path 143 is a path through which a current flows in the parallel connection state but not in the series connection state, and connects the first L common path 151L and the second L common path 152L.

[0019] The series connection state can be switched to by turning on the second switch 42 and turning off the first switch 41 and the third switch 43, and the parallel connection state can be switched to by turning off the second switch 42 and turning on the first switch 41 and the third switch 43. The first switch 41, the second switch 42, and the third switch 43 are, for example, relays, but are not necessarily relays and are not particularly limited as long as they are switches that can be switched on and off.

[0020] The first fuse 21 interrupts the first H common path 151H or the first L common path 151L. For example, the first fuse 21 is provided in the first H common path 151H and interrupts the first H common path 151H. The second fuse 22 interrupts the second H common path 152H or the second L common path 152L. For example, the second fuse 22 is provided in the second H common path 152H and interrupts the second H common path 152H. For example, the first fuse 21 and the second fuse 22 are active fuses that are cut off (interrupted) by an external signal, and one example is a pyrotechnic circuit breaker (pyro fuse) that can irreversibly interrupt a current. The first fuse 21 and the second fuse 22 interrupt the conductive path (the first conductive path 131 or the second conductive path 132) when a large current flows through the conductive path due to a short circuit abnormality. The pyrofuses used in the first fuse 21 and the second fuse 22 contain explosives and ignite the explosives based on a cutoff instruction signal from outside the first fuse 21 and the second fuse 22, thereby irreversibly cutting off the conductive path with the explosive force generated by the ignition of the explosives, thereby interrupting the conductive path. Specifically, the first fuse 21 and the second fuse 22 interrupt the conductive path upon receiving a cutoff instruction signal from outside (the cutoff control unit 61 in FIG. 1 ).

[0021] In the embodiment of the present disclosure, the first fuse 21 and the second fuse 22 are not limited to the above-mentioned active fuses, but may also be passive fuses (for example, melting fuses) that are cut off without receiving an external signal.

[0022] The first current sensor 51 is a current sensor that detects the current flowing in the first H common path 151H or the first L common path 151L. For example, the first current sensor 51 is provided in the first L common path 151L and detects the current flowing in the first L common path 151L. The second current sensor 52 is a current sensor that detects the current flowing in the second H common path 152H or the second L common path 152L. For example, the second current sensor 52 is provided in the second L common path 152L and detects the current flowing in the second L common path 152L. For example, the first current sensor 51 and the second current sensor 52 are sensors such as shunt-type sensors (e.g., shunt resistors) or Hall elements. The first current sensor 51 and the second current sensor 52 output the measurement results (current values) to the cutoff control unit 61.

[0023] Since the first fuse 21 and the first current sensor 51 are arranged separately on the positive and negative pole sides of the first battery module 11, and the second fuse 22 and the second current sensor 52 are arranged separately on the positive and negative pole sides of the second battery module 12, it becomes easier to arrange the components and the device can be made smaller.

[0024] The first main relay 31 is provided on the first conductive path 131. The first main relay 31 is controlled by, for example, the cutoff control unit 61 to switch between electrical continuity and non-conduction between the positive electrode side of the first battery module 11 and the positive electrode side of the load 70 via the first conductive path 131. In Fig. 1, the signal line from the cutoff control unit 61 to the first main relay 31 is not shown. Note that the first main relay 31 does not have to be controlled by the cutoff control unit 61, and may be controlled by an ECU (Electronic Control Unit) or the like.

[0025] The second main relay 32 is provided on the second conductive path 132. The second main relay 32 is controlled by, for example, the cutoff control unit 61 to switch between electrical continuity and non-conduction between the negative electrode side of the second battery module 12 and the negative electrode side of the load 70 via the second conductive path 132. In Fig. 1, the signal line from the cutoff control unit 61 to the second main relay 32 is not shown. Note that the second main relay 32 does not have to be controlled by the cutoff control unit 61, and may be controlled by an ECU or the like.

[0026] The precharge relay 33 and the precharge resistor 34 are connected in series, and the series-connected precharge relay 33 and precharge resistor 34 are connected in parallel with the first main relay 31. For example, when starting the electric vehicle, the first main relay 31 is turned off and the precharge relay 33 is turned on. This allows current to flow to the load 70 via the precharge resistor 34, thereby suppressing the occurrence of inrush current. The precharge relay 33 is controlled by, for example, a cutoff control unit 61. In FIG. 1 , the signal line from the cutoff control unit 61 to the precharge relay 33 is not shown. Note that the precharge relay 33 does not have to be controlled by the cutoff control unit 61, and may be controlled by an ECU or the like.

[0027] The shutoff control unit 61 controls the first fuse 21 and the second fuse 22. The shutoff control unit 61 may also control the first switch 41, the second switch 42, the third switch 43, the first main relay 31, the second main relay 32, and the pre-charge relay 33. The shutoff control unit 61 is a computer including a processor (microprocessor) and a memory. The memory may be a read-only memory (ROM) or a random access memory (RAM), and can store programs executed by the processor. The first switch 41, the second switch 42, the third switch 43, the first main relay 31, the second main relay 32, and the pre-charge relay 33 may be controlled by a control unit or an ECU different from the shutoff control unit 61.

[0028] The interruption control unit 61 drives the first fuse 21 based on the current value from the first current sensor 51, and drives the second fuse 22 based on the current value from the second current sensor 52. For example, when the current value from the first current sensor 51 or the current value from the second current sensor 52 is equal to or greater than a threshold value for determining an abnormal current value, the interruption control unit 61 drives the first fuse 21 and the second fuse 22 to interrupt the conduction path.

[0029] 1 , the first fuse 21, the second fuse 22, the first current sensor 51, and the second current sensor 52 may be components of the switching circuit 101. Alternatively, the first fuse 21, the second fuse 22, the first current sensor 51, and the second current sensor 52 do not have to be components of the switching circuit 101.

[0030] The first fuse 21 is connected to the positive electrode side or the negative electrode side of the first battery module 11, and can be shut off when an abnormality in the current flowing from the first battery module 11 is detected. The second fuse 22 is connected to the positive electrode side or the negative electrode side of the second battery module 12, and can be shut off when an abnormality in the current flowing from the second battery module 12 is detected. In this way, because the first fuse 21 and the second fuse 22 are provided directly below the first battery module 11 and the second battery module 12, even if the switching circuit 101 that switches between the series connection state and the parallel connection state fails (i.e., if at least one of the first switch 41, the second switch 42, and the third switch 43 is welded (thermally welded) (in other words, if it is constantly in an on state and cannot be turned off)), the first fuse 21 and the second fuse 22 can shut off the current flowing from the first battery module 11 and the second battery module 12. Furthermore, even if at least one of the first battery module 11 and the second battery module 12 in the parallel connection state experiences a short-circuit failure, the first fuse 21 and the second fuse 22 can prevent a current from continuing to flow. Therefore, in a system capable of switching the connection state of multiple battery modules, the conduction path can be safely interrupted. In other words, the short-circuit protection device 100 according to this embodiment can stably interrupt an overcurrent (current) by the first fuse 21 and the second fuse 22 regardless of the overcurrent state.

[0031] In addition, two fuses, a first fuse 21 and a second fuse 22, are provided, and the voltage applied to each fuse is low, so that even if the first fuse 21 and the second fuse 22 (pyrotechnical circuit breakers (pyrofuses)) have relatively low interrupting performance, overcurrent (current) can be interrupted stably.

[0032] Furthermore, among the first switch 41, the second switch 42, and the third switch 43, the rated voltages of the first switch 41 and the third switch 43 used in the above-mentioned parallel connection state may be higher than the rated voltage of the second switch 42 used in the above-mentioned series connection state.

[0033] Furthermore, the current ratings of the first switch 41 , the second switch 42 and the third switch 43 may be lower than the current ratings of the first main relay 31 and the second main relay 32 .

[0034] As described above, the short-circuit protection device 100 according to this embodiment shown in FIG. 1 can stably switch the battery voltage between a low voltage (for example, about 400 to 500 V) and a high voltage (for example, about 800 to 1000 V).

[0035] FIG. 2 is a functional block diagram showing another example of the schematic configuration of the short-circuit protection device according to the first embodiment.

[0036] As shown in FIG. 2 , the first fuse 21 may be provided on the positive pole side (first H common path 151H) of the first battery module 11, the second fuse 22 may be provided on the negative pole side (second L common path 152L) of the second battery module 12, the first current sensor 51 may be provided on the negative pole side (first L common path 151L) of the first battery module 11, and the second current sensor 52 may be provided on the positive pole side (second H common path 152H) of the second battery module 12.

[0037] In this case, too, the first fuse 21 and the first current sensor 51 are arranged separately on the positive and negative pole sides of the first battery module 11, and the second fuse 22 and the second current sensor 52 are arranged separately on the positive and negative pole sides of the second battery module 12, making it easier to arrange the components and enabling miniaturization.

[0038] Moreover, the first current sensor 51 and the second current sensor 52 may be arranged in parallel.

[0039] 1 or 2, when the tripping control unit 61 determines that the current values ​​from the first current sensor 51 and the second current sensor 52 are abnormal current values, the tripping control unit 61 sends a tripping signal (ignition signal) to the first fuse 21 and the second fuse 22. The tripping control unit 61 also drives the first fuse 21 and the second fuse 22 so that there is a time period during which arcs are generated simultaneously in the first fuse 21 and the second fuse 22.

[0040] When an arc occurs in the fuse, the resistance and inductance of the fuse increase. As a result, even at high voltages, the first fuse 21 and the second fuse 22 can be driven so that an arc occurs simultaneously in the first fuse 21 and the second fuse 22, thereby reducing the voltage applied to the first fuse 21 and the second fuse 22. In other words, even when inexpensive fuses with relatively poor interrupting performance (e.g., pyrofuses) are used as the first fuse 21 and the second fuse 22, the short-circuit protection device 100 can properly interrupt the current (overcurrent) and safely interrupt the conduction path, thereby achieving a cost-effective short-circuit protection device 100.

[0041] 1 or 2, the shutdown control unit 61 may drive the first fuse 21 at a different timing from the second fuse 22. In other words, the shutdown control unit 61 may output ignition signals to the first fuse 21 and the second fuse 22 at different times.

[0042] For example, if the first fuse 21 and the second fuse 22 were driven simultaneously, the current flowing through the conduction path would be instantaneously interrupted, causing an excessive voltage spike and possibly resulting in dielectric breakdown. In contrast, by differentiating the timing at which the first fuse 21 and the second fuse 22 are driven, the conduction path can be gradually interrupted over time, suppressing excessive voltage spikes and preventing dielectric breakdown. In a typical device for interrupting high voltages, the insulation distance must be increased to improve interruption performance, resulting in a larger and more expensive device. In contrast, because dielectric breakdown can be suppressed, the insulation distance does not need to be increased too much, i.e., the interruption performance does not need to be increased too much, thereby preventing the short-circuit protection device 100 from becoming larger and enabling cost reduction.

[0043] Furthermore, in the short-circuit protection device 100 according to this embodiment, the current flow (discharge current or charge current) differs between the low-voltage and high-voltage battery voltage modes, and the upper limit current values ​​that the first main relay 31 and the second main relay 32 provided between each battery module and the load 70 can interrupt differ. That is, the upper limit current values ​​that the first main relay 31 and the second main relay 32 can interrupt differ between the series connection state and the parallel connection state. The first fuse 21 and the second fuse 22 must interrupt the conduction path so that the current flowing through each main relay does not exceed the upper limit current value. Therefore, the abnormal current value that must be interrupted differs depending on the upper limit current value of each main relay, which differs between the series connection state and the parallel connection state. When passive fuses (e.g., melting fuses) are used as fuses, the current ranges that must be short-circuit protected differ, making it difficult to achieve both a long current life. In contrast, the short-circuit protection device 100 includes active fuses (e.g., pyroelectric fuses) as fuses, which can adjust the current value that must be short-circuit protected, thereby extending the current life of each main relay.

[0044] Furthermore, in a typical device that switches between low voltage and high voltage, if the switch used for switching fails, there is a problem that short circuit protection cannot be provided, resulting in an unsafe state. However, the short circuit protection device 100 according to this embodiment can solve this problem.

[0045] Furthermore, in a typical device, if the switching circuit fails and the switch is in the on state, there is a problem in that the device is unable to cut off and protect against overcurrent, but the short-circuit protection device 100 according to this embodiment can solve this problem.

[0046] (Variation 1 of Embodiment 1) A short-circuit protection device 100 according to Variation 1 of Embodiment 1 of the present disclosure will be described using FIG. 3, focusing on the differences from the short-circuit protection device 100 according to the above-described embodiment (FIG. 1 or FIG. 2).

[0047] FIG. 3 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device 100 according to a first modification of the first embodiment.

[0048] 3, the first fuse 21 and the first current sensor 51 may be provided adjacent to each other in a first H common path 151H (on the positive electrode side of the first battery module 11). Also, the second fuse 22 and the second current sensor 52 may be provided adjacent to each other in a second H common path 152H (on the positive electrode side of the second battery module 12).

[0049] As a result, the voltages applied from the first battery module 11 to the first fuse 21 and the first current sensor 51 are approximately the same, and the voltages applied from the second battery module 12 to the second fuse 22 and the second current sensor 52 are approximately the same. The cutoff control unit 61 is connected to the first fuse 21 and the first current sensor 51, but since approximately the same voltage is applied to the first fuse 21 and the first current sensor 51, insulation measures and the like are not required. Similarly, the cutoff control unit 61 is connected to the second fuse 22 and the second current sensor 52, but since approximately the same voltage is applied to the second fuse 22 and the second current sensor 52, insulation measures and the like are not required.

[0050] (Second Modification of First Embodiment) A switching circuit 101 according to a second modification of the first embodiment of the present disclosure will be described with reference to FIG.

[0051] FIG. 4 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device 100 according to the second modification of the first embodiment.

[0052] The switching circuit 101 switches between a series connection state in which the first battery module 11 and the second battery module 12 are connected in series and a parallel connection state in which the first battery module 11 and the second battery module 12 are connected in parallel. The switching circuit 101 has a first single-pole double-throw switch 44A that selectively switches the connection between the second H common path 152H and the second switching path 142 and the connection between the second H common path 152H and the first switching path 141, and a second single-pole double-throw switch 45A that selectively switches the connection between the first L common path 152L and the second switching path 142 and the connection between the first L common path 152L and the third switching path 143.

[0053] The first H common path 151H, the first L common path 151L, the second H common path 152H, and the second L common path 152L are paths through which current flows in both the above-described series connection state and the above-described parallel connection state. The first H common path 151H is connected to the positive electrode side of the first battery module 11, and the first L common path 151L is connected to the negative electrode side of the first battery module 11. The first H common path 151H is part of the first conductive path 131. The second H common path 152H is connected to the positive electrode side of the second battery module 12, and the second L common path 152L is connected to the negative electrode side of the second battery module 12. The second L common path 152L is part of the second conductive path 132.

[0054] The second switching path 142 is a path through which a current flows in the series connection state but not in the parallel connection state, and connects the first L common path 151L and the second H common path 152H. The first switching path 141 is a path through which a current flows in the parallel connection state but not in the series connection state, and connects the first H common path 151H and the second H common path 152H. The third switching path 143 is a path through which a current flows in the parallel connection state but not in the series connection state, and connects the first L common path 151L and the second L common path 152L.

[0055] The series connection state can be switched by setting the first single-pole double-throw switch 44A to a state in which the second H common path 152H and the second switching path 142 are connected, and setting the second single-pole double-throw switch 45A to a state in which the first L common path 151L and the second switching path 142 are connected.

[0056] The parallel connection state can be switched to by setting the first single-pole double-throw switch 44A to a state in which the second H common path 152H is connected to the first switching path 141, and setting the second single-pole double-throw switch 45A to a state in which the first L common path 151L is connected to the third switching path 143. The first single-pole double-throw switch 44A and the second single-pole double-throw switch 45A are, for example, mechanical relays, but they do not necessarily have to be relays and are not particularly limited as long as they are switches that can be switched on and off, and may be semiconductors.

[0057] Second Embodiment A short-circuit protection device 100 according to a second embodiment of the present disclosure will be described with reference to FIG. 5, focusing on differences from the short-circuit protection device 100 according to the above-described embodiment (FIGS. 1 to 3).

[0058] 5 is a functional block diagram showing an example of a schematic configuration of the short-circuit protection device 100 according to embodiment 2. The short-circuit protection device 100 according to embodiment 2 has a configuration that is more preferable for an external charger 80.

[0059] 5 , the short-circuit protection device 100 includes a first charging terminal 123, a second charging terminal 124, a first charging relay 91, and a second charging relay 92. The charger 80 is disposed between the first charging terminal 123 and the second charging terminal 124. Specifically, the positive pole of the charger 80 is connected to the first charging terminal 123, and the negative pole of the charger 80 is connected to the second charging terminal 124. The first charging relay 91 is connected between the first H common path 151H and the charger 80 (specifically, the first charging terminal 123), and the second charging relay 92 is connected between the second L common path 152L and the charger 80 (specifically, the second charging terminal 124). More specifically, the first charging relay 91 is connected to the first H common path 151H via the first main relay 31, and the second charging relay 92 is connected to the second L common path 152L via the second main relay 32.

[0060] The first charging relay 91 and the second charging relay 92 are controlled to be turned on and off by, for example, the cutoff control unit 61. Note that the first charging relay 91 and the second charging relay 92 may be controlled by a control unit or an ECU that is different from the cutoff control unit 61. For example, when charging the charger 80, the first charging relay 91 and the second charging relay 92 are controlled to be in the on state, but if a circuit failure or an abnormal state occurs during charging, the first charging relay 91 and the second charging relay 92 are controlled to be in the off state.

[0061] This allows for safe disconnection even if a circuit failure or abnormal state occurs during charging. In other words, in a system capable of switching the connection states of multiple battery modules, the conductive path can be safely disconnected when charging the charger 80.

[0062] (Modification of Second Embodiment) A short-circuit protection device 100 according to a modification of the second embodiment of the present disclosure will be described with reference to FIG. 6, focusing on differences from the short-circuit protection device 100 according to the second embodiment (FIG. 5) described above.

[0063] FIG. 6 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device 100 according to a modification of the second embodiment.

[0064] As shown in FIG. 6 , the connection point of the charger 80 within the short-circuit protection device 100 may be different from that shown in FIG. 5 , and the charger 80 may be connected between the switching circuit 101 and the above-mentioned main relays (first main relay 31 and second main relay 32).

[0065] Third Embodiment A short-circuit protection device 100 according to a third embodiment of the present disclosure will be described with reference to FIG. 7, focusing on differences from the short-circuit protection device 100 according to the above-described embodiment (FIGS. 1 to 6).

[0066] 7 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device 100 according to embodiment 3. The short-circuit protection device 100 according to embodiment 3 further includes a voltage detection unit 62, and is characterized in that it changes the trip determination threshold in accordance with the detected voltage.

[0067] 7, the short-circuit protection device 100 may include a voltage detection unit 62 that detects the voltage difference between the voltage of the first H common path 151H and the voltage of the second L common path 152L. The voltage detection unit 62 changes a threshold value for determining that the current value from the first current sensor 51 and the current value from the second current sensor 52 are abnormal current values, depending on the voltage difference.

[0068] As a result, the voltage difference detected by the voltage detection unit 62 differs between the series connection state and the parallel connection state, making it possible to determine whether the current connection state is a series connection state or a parallel connection state. For example, if a main relay is provided between each battery module and the load 70, the upper limit current value that the main relay can interrupt varies depending on the applied voltage. That is, the upper limit current value differs between the series connection state and the parallel connection state. The first fuse 21 and the second fuse 22 must interrupt the conduction path so that the current flowing through the main relay does not exceed the upper limit current value. Therefore, the abnormal current value that must be interrupted differs depending on the upper limit current value of the main relay, which differs between the series connection state and the parallel connection state. Therefore, by changing the threshold value for determining the abnormal current value depending on whether the current connection state is a series connection state or a parallel connection state, it is possible to set a threshold value corresponding to the connection state, thereby preventing a current exceeding the upper limit current value from flowing through the main relay and extending the current-carrying life of the main relay.

[0069] The voltage detection unit 62 may detect the voltage difference between the voltage of the first L common path 151L and the voltage of the second H common path 152H. Even in this case, it is possible to determine whether the current connection state is series or parallel, thereby achieving the same effect as described above.

[0070] Fourth Embodiment A short-circuit protection device 100 according to a fourth embodiment of the present disclosure will be described with reference to FIG. 8, focusing on differences from the short-circuit protection device 100 according to the above-described embodiments (FIGS. 1 to 7).

[0071] 8 is a functional block diagram showing an example of a schematic configuration of a short-circuit protection device 100 according to embodiment 4. The short-circuit protection device 100 according to embodiment 4 is characterized by further including a voltage detection unit 62, which detects failures in the first current sensor 51 and the second current sensor 52.

[0072] 8 , the short-circuit protection device 100 may include a voltage detection unit 62 that detects the voltage difference between the voltage of the first L common path 151L and the voltage of the second H common path 152H. The voltage detection unit 62 detects the voltage difference (specifically, the potential difference between the negative pole of the first battery module 11 and the positive pole of the second battery module 12), and if the voltage difference indicates that the first battery module 11 and the second battery module 12 are connected in series (in other words, if there is no detected potential difference), performs a fault diagnosis on the first current sensor 51 and the second current sensor 52.

[0073] In the series connection state, the current values ​​detected by the first current sensor 51 and the second current sensor 52 are normally the same, but if the current values ​​detected by the first current sensor 51 and the second current sensor 52 are different, there is a possibility that a malfunction has occurred in either the first current sensor 51 or the second current sensor 52. Therefore, a malfunction diagnosis of the first current sensor 51 and the second current sensor 52 can be performed when the series connection state is established.

[0074] The voltage detection unit 62 may detect the voltage difference between the voltage of the first H common path 151H and the voltage of the second L common path 152L. Even in this case, it is possible to determine whether the current connection state is series or parallel, thereby achieving the same effect as described above.

[0075] Fifth Embodiment A cutoff control unit 61 according to a fifth embodiment of the present disclosure will be described with reference to FIG.

[0076] Fig. 9 is a functional block diagram showing an example of a schematic configuration of the cutoff control unit 61 according to embodiment 5. Note that Fig. 9 also shows components other than the cutoff control unit 61.

[0077] The cutoff control unit 61 includes a first control unit 601, a second control unit 602, an ignition control unit (a first ignition control unit 603 and a second ignition control unit 633), a power supply 604, a first drive circuit 605, a power supply 614, and a second drive circuit 606. The first control unit 601 and the second control unit 602 are provided separately. For example, the first control unit 601 and the second control unit 602 may be formed as different components on the same board, or may be formed on different boards, or may be in different housings.

[0078] The first control unit 601 has a current value determination unit 611 and a communication unit 621. The current value determination unit 611 determines whether the current value (a) from the first current sensor 51 is equal to or greater than a first threshold value. The communication unit 621 performs communication between the first control unit 601 and the first ignition control unit 603, communication (c) between the first control unit 601 and the second control unit 602, and communication between the first control unit 601 and the ECU 608. The ECU 608 is an example of an external device.

[0079] Second control unit 602 has a current value determination unit 612 and a communication unit 622. Current value determination unit 612 determines whether the current value (b) from second current sensor 52 is equal to or greater than a second threshold value. Communication unit 622 performs communication between second control unit 602 and second ignition control unit 633, communication (c) between second control unit 602 and first control unit 601, and communication between second control unit 602 and ECU 608.

[0080] The first ignition control unit 603 includes an ignition signal output unit 613 and a fault diagnosis unit 623. The ignition signal output unit 613 drives the first fuse 21 when the current value from the first current sensor 51 is equal to or greater than a first threshold. Specifically, when the current value from the first current sensor 51 is equal to or greater than the first threshold, the ignition signal output unit 613 drives the first fuse 21 by outputting an ignition signal to a first drive circuit 605 for driving the first fuse 21. The power supply 604 supplies power to the first drive circuit 605, and the first drive circuit 605 can drive the first fuse 21 with the power supplied from the power supply 604. The fault diagnosis unit 623 diagnoses a fault in the cutoff control unit 61. For example, the fault diagnosis unit 623 diagnoses a fault in a circuit related to ignition drive, specifically, a fault in the first control unit 601, the first ignition control unit 603, and the first drive circuit 605.

[0081] The second ignition control unit 633 includes an ignition signal output unit 643 and a fault diagnosis unit 653. The ignition signal output unit 643 drives the second fuse 22 when the current value from the second current sensor 52 is equal to or greater than the second threshold. Specifically, when the current value from the second current sensor 52 is equal to or greater than the second threshold, the ignition signal output unit 643 drives the second fuse 22 by outputting an ignition signal to a second drive circuit 606 for driving the second fuse 22. The power supply 614 supplies power to the second drive circuit 606, and the second drive circuit 606 can drive the second fuse 22 with the power supplied from the power supply 614. The fault diagnosis unit 653 diagnoses faults in the cutoff control unit 61. For example, the fault diagnosis unit 653 diagnoses faults in circuits related to ignition drive, specifically, faults in the second control unit 602, the second ignition control unit 633, and the second drive circuit 606.

[0082] By providing the first control unit 601 and the second control unit 602 separately, even if one of the first control unit 601 and the second control unit 602 fails, the other can cut off the conductive path, thereby increasing the robustness of the cutting function.

[0083] For example, if the first drive circuit 605 fails, the cutoff function can be maintained by the second drive circuit 606 (second fuse 22). For example, if the first drive circuit 605 fails when the first battery module 11 and the second battery module 12 are connected in parallel, the cutoff function can be maintained by turning the first switch 41 on and the second switch 42 and the third switch 43 off. For example, if the first drive circuit 605 fails when the first battery module 11 and the second battery module 12 are connected in series, the cutoff function can be maintained by turning the first switch 41 off, the second switch 42 on, and the third switch 43 off.

[0084] For example, if the second drive circuit 606 fails, the cutoff function can be maintained by the first drive circuit 605 (first fuse 21). For example, if the second drive circuit 606 fails when the first battery module 11 and the second battery module 12 are connected in parallel, the cutoff function can be maintained by turning the first switch 41 and the second switch 42 off and the third switch 43 on. For example, if the second drive circuit 606 fails when the first battery module 11 and the second battery module 12 are connected in series, the cutoff function can be maintained by turning the first switch 41 off, the second switch 42 on, and the third switch 43 off.

[0085] In this way, the shutoff function can be maintained, so that, for example, the vehicle can be continued to be driven without stopping.

[0086] For example, first control unit 601 may monitor a first communication state between first control unit 601 and first ignition control unit 603, and second control unit 602 may monitor a second communication state between second control unit 602 and second ignition control unit 633. Then, when a failure occurs in cutoff control unit 61, first control unit 601 may notify ECU 608 of the first communication state, and second control unit 602 may notify ECU 608 of the second communication state. In this way, when a failure occurs, the communication state between first control unit 601 and first ignition control unit 603 and the communication state between second control unit 602 and second ignition control unit 633 in cutoff control unit 61 can be notified to an external device such as ECU 608.

[0087] For example, the first control unit 601 and the second control unit 602 may be able to communicate with each other, and if a failure occurs in the first control unit 601, the second control unit 602 may notify the ECU 608 of the first communication state and the second communication state, and if a failure occurs in the second control unit 602, the first control unit 601 may notify the ECU 608 of the first communication state and the second communication state. In this way, even if one of the first control unit 601 and the second control unit 602 fails, the other can notify an external device such as the ECU 608 of the communication state of the other one.

[0088] For example, when the first control unit 601 operates as a master and the second control unit 602 operates as a slave, if a failure occurs in the first control unit 601, the second control unit 602 operates as the master, and when the second control unit 602 operates as a master and the first control unit 601 operates as a slave, if a failure occurs in the second control unit 602, the first control unit 601 may operate as the master. As a result, even if one of the first control unit 601 and the second control unit 602 that was operating as the master fails, the other of the first control unit 601 and the second control unit 602 that was operating as the slave can operate as the master.

[0089] (Variation of Embodiment 5) A cutoff control unit 61 according to a variation of embodiment 5 of the present disclosure will be described with reference to FIG. 10, focusing on the differences from the cutoff control unit 61 according to embodiment 5 described above (FIG. 9).

[0090] As shown in Figure 10, the cut-off control unit 61 does not have to have a first ignition control unit 603 for the first drive circuit 605 (first fuse 21) and a second ignition control unit 633 for the second drive circuit 606 (second fuse 22), and may have a single ignition control unit 663 for the first drive circuit 605 and the second drive circuit 606.

[0091] The ignition control unit 663 has an ignition signal output unit 673 and a fault diagnosis unit 683. The ignition signal output unit 673 has the functions of the ignition signal output units 613 and 643 described in the fifth embodiment. That is, when the current value from the first current sensor 51 is equal to or greater than the first threshold, the ignition control unit 663 outputs an ignition signal to the first drive circuit 605 to drive the first fuse 21, and when the current value from the second current sensor 52 is equal to or greater than the second threshold, the ignition control unit 663 outputs an ignition signal to the second drive circuit 606 to drive the second fuse 22. The fault diagnosis unit 683 has the functions of the fault diagnosis units 623 and 653 described in the fifth embodiment. That is, the fault diagnosis unit 683 diagnoses faults in the first control unit 601, the first drive circuit 605, the second control unit 602, the second drive circuit 606, and the ignition control unit 663.

[0092] The power supply 624 supplies power to the first drive circuit 605 and the second drive circuit 606. In other words, the first drive circuit 605 and the second drive circuit 606 may be supplied with power from a single power supply 624. In this case, however, the ignition control unit 663 outputs an ignition signal to the first drive circuit 605 at a timing different from that of the second drive circuit 606.

[0093] For example, if the first drive circuit 605 and the second drive circuit 606 simultaneously drive the first fuse 21 and the second fuse 22, there is a problem that the voltage of the power supply 624 drops suddenly. Therefore, by providing one ignition control unit 663 for the first drive circuit 605 and the second drive circuit 606, it becomes possible to individually control the timing of outputting ignition signals to the first drive circuit 605 and the second drive circuit 606. This makes it possible to output ignition signals so as not to simultaneously drive the first fuse 21 and the second fuse 22, thereby preventing a sudden drop in the voltage of the power supply 624. Furthermore, this allows for a smaller size than when two ignition control units and two power supplies are provided.

[0094] (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.

[0095] In the above embodiment, each component included in the short-circuit protection device 100 may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0096] Some or all of the functions of the shutdown control unit 61 according to the above embodiment are typically realized as an LSI, which is an integrated circuit. These may be individually integrated into single chips, or some or all of them may be integrated into a single chip. Furthermore, the integrated circuit is not limited to an LSI, and may be realized by a dedicated circuit or a general-purpose processor. It is also possible to use an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within an LSI.

[0097] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, that technology may naturally be used to integrate the components included in the short-circuit protection device 100 into an integrated circuit.

[0098] 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.

[0099] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0100] (Technology 1) A short-circuit protection device including: a switching circuit that switches between a series connection state in which a first battery module and a second battery module are connected in series and a parallel connection state in which the first battery module and the second battery module are connected in parallel; and paths through which current flows in both the series connection state and the parallel connection state, the paths including a first H common path connected to the positive electrode side of the first battery module, a first L common path connected to the negative electrode side of the first battery module, a second H common path connected to the positive electrode side of the second battery module, and a second L common path connected to the negative electrode side of the second battery module.

[0101] According to this, for example, a first fuse is connected to the positive or negative pole of a first battery module, and the first fuse can be shut off when an abnormality in the current flowing from the first battery module is detected. Also, for example, a second fuse is connected to the positive or negative pole of a second battery module, and the second fuse can be shut off when an abnormality in the current flowing from the second battery module is detected. In this way, when the first fuse and the second fuse are provided directly below the first battery module and the second battery module, even if a switching circuit that switches between a series connection state and a parallel connection state fails, the first fuse and the second fuse can shut off the current flowing from the first battery module and the second battery module. Furthermore, even if a short-circuit failure occurs in at least one of the first battery module and the second battery module in the parallel connection state, the first fuse and the second fuse can prevent the current from continuing to flow. Therefore, the conductive path can be safely shut off in a system that can switch the connection state of multiple battery modules.

[0102] (Technology 2) The short-circuit protection device according to Technology 1 further includes a second switching path connecting the first L common path and the second H common path, through which a current flows in the series connection state and does not flow in the parallel connection state, and a first switching path connecting the first H common path and the second H common path, and a third switching path connecting the first L common path and the second L common path, through which a current flows in the parallel connection state and does not flow in the series connection state, and the switching circuit has a first switch provided on the first switching path, a second switch provided on the second switching path, and a third switch provided on the third switching path.

[0103] According to this, the series connection state can be switched to by turning on the second switch and turning off the first switch and the third switch, and the parallel connection state can be switched to by turning off the second switch and turning on the first switch and the third switch.

[0104] (Technology 3) The short-circuit protection device according to Technology 1 further includes a second switching path connecting the first L common path and the second H common path, through which a current flows in the series connection state but not in the parallel connection state, and a first switching path connecting the first H common path and the second H common path, and a third switching path connecting the first L common path and the second L common path, through which a current flows in the parallel connection state but not in the series connection state, and the switching circuit includes a second single-pole double-throw switch that selectively switches the connection between the first L common path and the second switching path and the connection between the first L common path and the third switching path, and a first single-pole double-throw switch that selectively switches the connection between the second H common path and the second switching path and the connection between the second H common path and the first switching path.

[0105] This prevents the second switching path and the first switching path from being connected at the same time, and prevents the second switching path and the third switching path from being connected at the same time, which not only prevents a short circuit caused by a switch malfunction or failure, but also prevents a short circuit caused by an incorrect switch switching order or a shift in switching timing.

[0106] (Technology 4) The short-circuit protection device according to Technology 2, wherein the rated voltages of the first switch and the third switch are higher than the rated voltage of the second switch.

[0107] This allows the switching circuit to maintain sufficient voltage resistance while also being small and low cost.

[0108] (Technology 5) The short-circuit protection device according to Technology 2 or 4, further comprising a first main relay connected between the first H common path and a load, and a second main relay connected between the second L common path and the load, wherein the current ratings of the first switch, the second switch, and the third switch are lower than the current ratings of the first main relay and the second main relay.

[0109] This allows the switching circuit to be made small and low cost while ensuring safe operation.

[0110] (Technology 6) The short-circuit protection device according to any one of Technologies 1 to 5, further comprising a first charging relay connected between the first H common path and a charger, and a second charging relay connected between the second L common path and the charger.

[0111] This allows the conductive path to be safely cut off when charging the charger in a system that can switch the connection state of multiple battery modules.

[0112] (Technology 7) A short-circuit protection device according to any one of technologies 1 to 6, further comprising a first fuse that cuts off the first H common path or the first L common path, and a second fuse that cuts off the second H common path or the second L common path.

[0113] Thus, the short circuit protection device may comprise a first fuse and a second fuse.

[0114] (Technology 8) The short-circuit protection device according to Technology 7 further includes a first current sensor that detects a current flowing in the first H common path or the first L common path, a second current sensor that detects a current flowing in the second H common path or the second L common path, and an interruption control unit that drives the first fuse based on a current value from the first current sensor and drives the second fuse based on a current value from the second current sensor.

[0115] In this manner, the short-circuit protection device may include a first current sensor, a second current sensor, and a cut-off control unit.

[0116] (Technology 9) A short-circuit protection device as described in Technology 8, wherein the first fuse is provided in the first H common path, the second fuse is provided in the second H common path, the first current sensor is provided in the first L common path, and the second current sensor is provided in the second L common path.

[0117] With this, the first fuse and the first current sensor are arranged separately on the positive and negative pole sides of the first battery module, and the second fuse and the second current sensor are arranged separately on the positive and negative pole sides of the second battery module, making it easier to arrange the components and enabling miniaturization.

[0118] (Technology 10) A short-circuit protection device as described in Technology 8, wherein the first fuse is provided in the first H common path, the second fuse is provided in the second L common path, the first current sensor is provided in the first L common path, and the second current sensor is provided in the second H common path.

[0119] With this, the first fuse and the first current sensor are arranged separately on the positive and negative pole sides of the first battery module, and the second fuse and the second current sensor are arranged separately on the positive and negative pole sides of the second battery module, making it easier to arrange the components and enabling miniaturization.

[0120] (Technology 11) The short circuit protection device according to Technology 10, wherein the first current sensor and the second current sensor are arranged in parallel.

[0121] This ensures that the current flowing through the two current sensors is always in the opposite direction, and the electromagnetic repulsive force generated between the two current sensors in the event of a short circuit can cause them to repel each other, thereby preventing short-circuit failures due to contact even if destruction occurs during a short circuit.

[0122] (Technology 12) A short-circuit protection device as described in Technology 8, wherein the first fuse and the first current sensor are arranged adjacent to each other in the first H common path, and the second fuse and the second current sensor are arranged adjacent to each other in the second H common path.

[0123] According to this, the voltage applied from the first battery module to the first fuse and the first current sensor is approximately the same, and the voltage applied from the second battery module to the second fuse and the second current sensor is approximately the same. The cutoff control unit is connected to the first fuse and the first current sensor, but because approximately the same voltage is applied to the first fuse and the first current sensor, insulation measures and the like are not required. Similarly, the cutoff control unit is connected to the second fuse and the second current sensor, but because approximately the same voltage is applied to the second fuse and the second current sensor, insulation measures and the like are not required.

[0124] (Technology 13) A short-circuit protection device according to any one of Technologies 8 to 12, wherein the interruption control unit drives the first fuse and the second fuse so that there is a time period during which arcs occur simultaneously in the first fuse and the second fuse.

[0125] According to this, when an arc occurs in the fuse, the resistance value and inductance value of the fuse become large. As a result, even at high voltages, the voltage applied to the first fuse and the second fuse can be reduced by driving the first fuse and the second fuse so that an arc occurs simultaneously in the first fuse and the second fuse. In other words, even if inexpensive fuses with relatively low interrupting performance (e.g., pyro fuses) are used as the first fuse and the second fuse, the conduction path can be safely interrupted, thereby realizing a short-circuit protection device with high cost performance.

[0126] (Technology 14) The short-circuit protection device according to any one of Technologies 8 to 13, wherein the cutoff control unit drives the first fuse at a timing different from the timing at which the second fuse is driven.

[0127] For example, if the first fuse and the second fuse were activated simultaneously, the current flowing through the conduction path would be instantaneously interrupted, causing an excessive voltage spike and possibly resulting in dielectric breakdown. By differentiating the timing of activating the first fuse from the timing of activating the second fuse, the conduction path can be gradually interrupted over time, suppressing the excessive voltage spike and thus preventing dielectric breakdown. Furthermore, because dielectric breakdown can be suppressed, the insulation distance does not need to be increased too much, meaning that the interruption performance does not need to be increased too much, preventing the short-circuit protection device from becoming too large and enabling cost reduction.

[0128] (Technology 15) A short-circuit protection device as described in any of Technologies 8 to 14, further comprising a voltage detection unit that detects the voltage difference between the voltage of the first H common path and the voltage of the second L common path, or the voltage difference between the voltage of the first L common path and the voltage of the second H common path, and the cut-off control unit changes a threshold value for determining that the current value from the first current sensor and the current value from the second current sensor are abnormal current values ​​depending on the voltage difference.

[0129] According to this, the voltage difference detected by the voltage detection unit differs between the series connection state and the parallel connection state, making it possible to determine whether the current connection state is a series connection state or a parallel connection state. For example, if a main relay is provided between each battery module and a load, the upper limit current value that the main relay can interrupt varies depending on the applied voltage, i.e., the upper limit current value differs between the series connection state and the parallel connection state. Since the first fuse and the second fuse need to interrupt the conduction path so that the current flowing through the main relay does not exceed the upper limit current value, the abnormal current value that must be interrupted differs depending on the upper limit current value of the main relay, which differs between the series connection state and the parallel connection state. Therefore, by changing the threshold value for determining the abnormal current value depending on whether the current connection state is a series connection state or a parallel connection state, it is possible to set a threshold value corresponding to the connection state, thereby preventing a current exceeding the upper limit current value from flowing through the main relay and extending the current-carrying life of the main relay.

[0130] (Technology 16) A short-circuit protection device described in any of Technologies 8 to 15, further comprising a voltage detection unit that detects a voltage difference between the voltage of the first H common path and the voltage of the second L common path, or a voltage difference between the voltage of the first L common path and the voltage of the second H common path, and the cut-off control unit performs a fault diagnosis of the first current sensor and the second current sensor when the voltage difference indicates that the connection state between the first battery module and the second battery module is the series connection state.

[0131] According to this, in the series connection state, the current values ​​detected by the first current sensor and the second current sensor are normally the same, but if the current values ​​detected by the first current sensor and the second current sensor are different, there is a possibility that one of the first current sensor and the second current sensor is faulty. Therefore, it is possible to perform fault diagnosis of the first current sensor and the second current sensor when the series connection state is established.

[0132] (Technology 17) A short-circuit protection device according to any one of Technologies 8 to 16, wherein the first fuse and the second fuse are pyrotechnic circuit breakers capable of irreversible circuit breaker operation, and the circuit breaker control unit includes a first control unit that determines whether or not a current value from the first current sensor is equal to or greater than a first threshold value, a second control unit that determines whether or not a current value from the second current sensor is equal to or greater than a second threshold value, and an ignition control unit that drives the first fuse when the current value from the first current sensor is equal to or greater than the first threshold value, and drives the second fuse when the current value from the second current sensor is equal to or greater than the second threshold value, and wherein the first control unit and the second control unit are provided separately.

[0133] According to this, since the first control unit and the second control unit are provided separately, even if one of the first control unit and the second control unit fails, the other can cut off the conductive path, thereby increasing the robustness of the cutting function.

[0134] (Technology 18) The short circuit protection device according to Technology 17, wherein the ignition control unit diagnoses a fault in the cutoff control unit.

[0135] This allows for diagnosis of a fault in the cutoff control unit.

[0136] (Technology 19) A short-circuit protection device as described in Technology 18, in which the first control unit monitors a first communication state between the first control unit and the ignition control unit, and the second control unit monitors a second communication state between the second control unit and the ignition control unit, and when a failure occurs in the shutdown control unit, the first control unit notifies an external device of the first communication state, and the second control unit notifies the external device of the second communication state.

[0137] According to this, in the event of a failure, the communication state between the first control unit and the ignition control unit and the communication state between the second control unit and the ignition control unit within the cutoff control unit can be notified to an external device.

[0138] (Technology 20) The first control unit and the second control unit are capable of communicating with each other, and when a failure occurs in the first control unit, the second control unit notifies the external device of the first communication state and the second communication state, and when a failure occurs in the second control unit, the first control unit notifies the external device of the first communication state and the second communication state.A short-circuit protection device as described in Technology 19.

[0139] With this, even if one of the first control unit and the second control unit fails, the communication state of the one can be notified to the external device by the other control unit.

[0140] (Technology 21) A short-circuit protection device according to any one of technologies 18 to 20, wherein when the first control unit operates as a master and the second control unit operates as a slave, if a failure occurs in the first control unit, the second control unit operates as a master, and when the second control unit operates as a master and the first control unit operates as a slave, if a failure occurs in the second control unit, the first control unit operates as a master.

[0141] According to this, even if the control unit that was operating as the master of the first control unit and the second control unit fails, the control unit that was operating as the slave of the first control unit and the second control unit can become the master and operate.

[0142] (Technology 22) A short-circuit protection device according to any one of Technologies 17 to 21, wherein the shutdown control unit has a first drive circuit for driving the first fuse, a second drive circuit for driving the second fuse, and a power supply for supplying power to the first drive circuit and the second drive circuit, and the ignition control unit drives the first fuse by outputting an ignition signal to the first drive circuit when the current value from the first current sensor is equal to or greater than the first threshold, and drives the second fuse by outputting an ignition signal to the second drive circuit when the current value from the second current sensor is equal to or greater than the second threshold, and the timing for outputting the ignition signal to the first drive circuit is made different from the timing for outputting the ignition signal to the second drive circuit.

[0143] For example, if the first drive circuit and the second drive circuit simultaneously drive the first fuse and the second fuse, a sudden drop in power supply voltage may occur. Therefore, by providing a single ignition control unit for the first drive circuit and the second drive circuit, the timing of outputting the ignition signal to the first drive circuit and the second drive circuit can be individually controlled. This allows the ignition signal to be output so as not to simultaneously drive the first fuse and the second fuse, preventing a sudden drop in power supply voltage. Furthermore, this allows for a more compact design than when two ignition control units and two power supplies are provided.

[0144] REFERENCE SIGNS LIST 11 First battery module 12 Second battery module 21 First fuse 22 Second fuse 31 First main relay 32 Second main relay 33 Pre-charge relay 34 Pre-charge resistor 41 First switch 42 Second switch 43 Third switch 44A First single-pole double-throw switch 45A Second single-pole double-throw switch 51 First current sensor 52 Second current sensor 61 Shut-off control unit 62 Voltage detection unit 70 Load 80 Charger 91 First charging relay 92 Second charging relay 100 Short-circuit protection device 101 Switching circuit 111 First A input terminal 112 First B input terminal 113 Second A input terminal 114 Second B input terminal 121 First output terminal 122 Second output terminal 123 First charging terminal 124 Second charging terminal 131 First conductive path 132 Second conductive path 141 First switching path 142 Second switching path 143 Third switching path 151H First H common path 151L First L common path 152H Second H common path 152L Second L common path 601 First control unit 602 Second control unit 603 First ignition control unit 604, 614, 624 Power supply 605 First drive circuit 606 Second drive circuit 608 ECU 611, 612 Current value determination unit 621, 622 Communication unit 613, 643, 673 Ignition signal output unit 623, 653, 683 Fault diagnosis unit 633 Second ignition control unit 663 Ignition control unit

Claims

1. A switching circuit that switches between a series connection state in which the first battery module and the second battery module are connected in series, and a parallel connection state in which the first battery module and the second battery module are connected in parallel, A current-carrying path in both the series and parallel connection states, comprising: a first H common path connected to the positive terminal side of the first battery module; a first L common path connected to the negative terminal side of the first battery module; a second H common path connected to the positive terminal side of the second battery module; and a second L common path connected to the negative terminal side of the second battery module. Short-circuit protection device.

2. moreover, A path through which current flows in the series connection state and which does not flow in the parallel connection state, comprising a second switching path connecting the first L common path and the second H common path, A path through which current flows in the parallel connection state and which does not flow in the series connection state, comprising a first switching path connecting the first H common path and the second H common path, and a third switching path connecting the first L common path and the second L common path, The switching circuit includes a first switch provided on the first switching path, a second switch provided on the second switching path, and a third switch provided on the third switching path. The short-circuit protection device according to claim 1.

3. moreover, A path through which current flows in the series connection state and which does not flow in the parallel connection state, comprising a second switching path connecting the first L common path and the second H common path, A path through which current flows in the parallel connection state and which does not flow in the series connection state, comprising a first switching path connecting the first H common path and the second H common path, and a third switching path connecting the first L common path and the second L common path, The switching circuit is, A second single-pole double-throw switch that selectively switches the connection between the first L common path and the second switching path, and the connection between the first L common path and the third switching path, The system includes a first single-pole double-throw switch that selectively switches the connection between the second H common path and the second switching path, and the connection between the second H common path and the first switching path. The short-circuit protection device according to claim 1.

4. The rated voltages of the first and third switches are higher than the rated voltage of the second switch. The short-circuit protection device according to claim 2.

5. moreover, A first main relay connected between the first common path and the load, The system comprises a second main relay connected between the second L common path and the load, The current ratings of the first switch, the second switch, and the third switch are lower than the current ratings of the first main relay and the second main relay. The short-circuit protection device according to claim 2.

6. moreover, A first charging relay connected between the first common circuit and the charger, The system comprises a second charging relay connected between the second L common circuit and the charger. The short-circuit protection device according to claim 1.

7. moreover, A first fuse that interrupts the first common path H or the first common path L, The system comprises a second fuse that interrupts the second H common path or the second L common path. A short-circuit protection device according to any one of claims 1 to 6.

8. moreover, A first current sensor for detecting the current flowing through the first common path H or the first common path L, A second current sensor for detecting the current flowing through the second H common path or the second L common path, The system includes a circuit breaker control unit that drives the first fuse based on the current value from the first current sensor and drives the second fuse based on the current value from the second current sensor. The short-circuit protection device according to claim 7.

9. The first fuse is provided in the first common circuit H, The second fuse is provided in the second H common circuit, The first current sensor is provided in the first L common path, The second current sensor is provided in the second L common path. The short-circuit protection device according to claim 8.

10. The first fuse is provided in the first common circuit H, The second fuse is provided in the second L common circuit, The first current sensor is provided in the first L common path, The second current sensor is provided in the second H common path. The short-circuit protection device according to claim 8.

11. The first current sensor and the second current sensor are arranged in parallel. The short-circuit protection device according to claim 10.

12. The first fuse and the first current sensor are provided adjacent to each other in the first common circuit H. The second fuse and the second current sensor are provided adjacent to each other in the second H common path. The short-circuit protection device according to claim 8.

13. The interruption control unit drives the first fuse and the second fuse such that there is a period of time when arcs occur simultaneously in the first fuse and the second fuse. The short-circuit protection device according to claim 8.

14. The interruption control unit causes the timing for driving the first fuse and the timing for driving the second fuse to be different. The short-circuit protection device according to claim 8.

15. Furthermore, it includes a voltage detection unit that detects the voltage difference between the voltage of the first H common path and the voltage of the second L common path, or the voltage difference between the voltage of the first L common path and the voltage of the second H common path. The cutoff control unit changes the threshold value for determining whether the current value from the first current sensor and the current value from the second current sensor are abnormal current values, according to the voltage difference. The short-circuit protection device according to claim 8.

16. Furthermore, it includes a voltage detection unit that detects the voltage difference between the voltage of the first H common path and the voltage of the second L common path, or the voltage difference between the voltage of the first L common path and the voltage of the second H common path. The interruption control unit performs fault diagnosis of the first current sensor and the second current sensor when the voltage difference indicates that the connection state between the first battery module and the second battery module is the series connection state. The short-circuit protection device according to claim 8.

17. The first fuse and the second fuse are pyrotechnic circuit breakers capable of irreversible interruption. The aforementioned cutoff control unit, A first control unit that determines whether the current value from the first current sensor is equal to or greater than a first threshold, A second control unit that determines whether the current value from the second current sensor is equal to or greater than a second threshold, The system includes an ignition control unit that drives the first fuse when the current value from the first current sensor is equal to or greater than the first threshold, and drives the second fuse when the current value from the second current sensor is equal to or greater than the second threshold, The first control unit and the second control unit are provided in separate units. The short-circuit protection device according to claim 8.

18. The ignition control unit diagnoses a malfunction in the shut-off control unit. The short-circuit protection device according to claim 17.

19. The first control unit monitors the first communication state between the first control unit and the ignition control unit, The second control unit monitors the second communication state between the second control unit and the ignition control unit, If a malfunction occurs in the aforementioned circuit breaker control unit, The first control unit notifies the external device of the first communication state, The second control unit notifies the external device of the second communication state. The short-circuit protection device according to claim 18.

20. The first control unit and the second control unit are capable of communicating with each other. If a failure occurs in the first control unit, the second control unit notifies the external device of the first communication status and the second communication status. If a failure occurs in the second control unit, the first control unit shall notify the external device of the first communication status and the second communication status. The short-circuit protection device according to claim 19.

21. When the first control unit is operating as a master and the second control unit is operating as a slave, if a failure occurs in the first control unit, the second control unit will operate as a master. When the second control unit is operating as a master and the first control unit is operating as a slave, if a failure occurs in the second control unit, the first control unit will operate as a master. The short-circuit protection device according to claim 18.

22. The aforementioned cutoff control unit, A first drive circuit for driving the first fuse, A second drive circuit for driving the second fuse, It comprises a power supply that supplies power to the first drive circuit and the second drive circuit, The ignition control unit, If the current value from the first current sensor is greater than or equal to the first threshold, the first fuse is driven by outputting an ignition signal to the first drive circuit; if the current value from the second current sensor is greater than or equal to the second threshold, the second fuse is driven by outputting an ignition signal to the second drive circuit. The timing of outputting the ignition signal to the first drive circuit and the timing of outputting the ignition signal to the second drive circuit are made different. The short-circuit protection device according to claim 17.