Vehicle power supply device

Abstract

To provide a vehicle power supply device capable of maintaining, even at a power supply failure, the operating capacity of an on-vehicle load required to safely evacuate the vehicle.SOLUTION: A vehicle power supply device 10 comprises: a voltage monitor 13 that detects an abnormal state of each of cells 111, 112, ..., 113; a cutoff unit 14 that disconnects the cells 111, 112, ..., 113 from an electric circuit 12; a stop unit 15 that stops operation of an on-vehicle load 20; and a control unit 17 that acquires abnormality information I from the voltage monitor 13 and controls operation of the cutoff unit 14 and the stop unit 15. The control unit 17 operates the cutoff unit 14 to disconnect the abnormal cell 111 from the electric circuit 12 on the basis of the abnormality information I, and operates the stop unit 15 to stop operation of non-safety devices 21, 23 with low priority according to priority when a drop in power occurs due to disconnection of the cell 111 by the cutoff unit 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply device for a vehicle. [Background technology]

[0002] A conventional vehicle power supply system is disclosed in, for example, Patent Document 1. The conventional vehicle power supply system is provided with an auxiliary battery capable of supplying power to the vehicle loads such as the brake and steering during automatic driving in preparation for the failure of the high-voltage power supply or the DC / DC converter. In addition, the conventional vehicle power supply system is normally connected to the DC / DC converter and is configured such that, in the event of a failure of the high-voltage power supply or the DC / DC converter, the auxiliary battery is disconnected from the DC / DC converter to supply power to the vehicle loads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-36465 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a conventional vehicle power supply system, it is necessary to mount an auxiliary battery in addition to the auxiliary power supply, which restricts the mounting space in the vehicle and increases costs. In addition, in a conventional vehicle power supply system, if an abnormality occurs in the high-voltage power supply or the DC / DC converter, the auxiliary battery is electrically disconnected, making it impossible to store electricity in the auxiliary battery. In addition, if the auxiliary battery deteriorates over time, the remaining capacity of the auxiliary battery decreases. As a result, if a vehicle load that consumes a large current, such as a brake or steering, is operated multiple times, the remaining capacity of the auxiliary battery may be used up. In this case, therefore, there is a risk that the operating capacity of the vehicle load may decrease.

[0005] An object of the present invention is to provide a power supply device for a vehicle that can maintain the operating capacity of the on-board loads required to safely evacuate the vehicle even in the event of a power supply failure. [Means for solving the problem]

[0006] The vehicle power supply device of the present invention is a vehicle power supply device that outputs and supplies power to each of a plurality of vehicle loads from a power source composed of a plurality of cells via an electrical circuit, and is equipped with an abnormality detection unit that detects an abnormal state of each cell, a cut-off unit that disconnects the cell from the electrical circuit, a stopping unit that stops operation of the vehicle load, and a control unit that acquires abnormality information indicating the abnormal state from the abnormality detection unit and controls the operation of the cut-off unit and the stopping unit, and the control unit operates the cut-off unit to disconnect the abnormal cell from the electrical circuit based on the abnormality information, and operates the stopping unit to stop operation of a vehicle load with a lower priority in accordance with the priority when supplying power to each of the vehicle loads when a decrease in power occurs due to disconnection of the cell by the cut-off unit. Effect of the Invention

[0007] According to the vehicle power supply device of the present invention, it is possible to identify an abnormal state of a cell that constitutes the power supply and to disconnect the abnormal cell from the electric circuit. Furthermore, according to the vehicle power supply device of the present invention, when power is reduced due to disconnection of a cell, it is possible to stop operation of an on-board load that has a low priority to supply power. This allows power to be continuously supplied from the power supply to an on-board load that has a high priority, i.e., that is necessary for safely evacuating the vehicle, and the operating capacity of the necessary on-board load can be maintained. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle power supply device according to an embodiment of the present invention; [Diagram 2] 4A and 4B are diagrams for explaining the operation of the vehicle power supply device when the power supply fails. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a vehicle power supply device according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition to the embodiment described below, the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0010] 1, a vehicle power supply device 10 of this embodiment includes a power source 11, an electric circuit 12, a voltage monitor 13 as an abnormality detection unit, a cutoff unit 14, and a stop unit 15, and outputs and supplies electric power to an in-vehicle load 20. Furthermore, the vehicle power supply device 10 includes a control unit 17 that controls the operation of the cutoff unit 14 and the stop unit 15 based on abnormality information I output from the voltage monitor 13.

[0011] 1, four vehicle loads 20 are exemplified: a non-safety device 21, a safety device (brakes, etc.) 22, a non-safety device 23, and a safety device (steering, etc.) 24. The non-safety device 21 and the non-safety device 23 are vehicle loads 20 that do not need to be activated when the power source 11 fails and the vehicle is safely evacuated. On the other hand, the safety device (brakes, etc.) 22 and the safety device (steering, etc.) 24 are vehicle loads 20 that need to be activated when the power source 11 fails and the vehicle is safely evacuated.

[0012] The power source 11 is composed of a plurality of cells 111, 112, ..., 113 connected in series. This allows the power source 11 to output high voltage power. For the sake of explanation, the cells 111, 112, ..., 113 are shown as an example, but it goes without saying that the number of cells is determined based on the power required in the vehicle.

[0013] The electric circuit 12 electrically connects the power source 11 to an auxiliary power source 16 that supplies power to auxiliary devices of the vehicle. The electric circuit 12 also electrically connects the power source 11 to a plurality of on-vehicle loads 20, that is, a non-safety device 21, a safety device (brakes, etc.) 22, a non-safety device 23, and a safety device (steering, etc.) 24.

[0014] The electric circuit 12 includes a step-down device 121 including, for example, a DC / DC converter, and steps down the power supplied from the high-voltage power supply 11 and outputs and supplies the power to the auxiliary power supply 16 and the vehicle-mounted load 20. The electric circuit 12 is provided with a plurality of switches 122, 123, and 124, and the supply of power to the auxiliary power supply 16 and the vehicle-mounted load 20 is switched by switching each of the switches 122, 123, and 124 between on and off.

[0015] The voltage monitor 13 detects the voltage across each of the cells 111, 112, ..., 113 of the power source 11, i.e., between the cells. Then, when the voltage detected for the corresponding cell 111, 112, ..., 113 is lower than the reference voltage, each voltage monitor 13 outputs abnormality information I indicating an abnormal state to the control unit 17.

[0016] The cutoff unit 14 is provided in the power source 11 and electrically separates each of the cells 111, 112, ..., 113 from the electric circuit 12. Specifically, the cutoff unit 14 has switches 141, 142, 143, and 144 in order to separate the cell 111 from the electric circuit 12 when the cell 111 is in an abnormal state. The switches 141 and 142 are in a conducting state (closed state) as shown in FIG. 1 when the cell 111 is in a normal state (i.e., normal time), and are switched to a cutoff state (open state) as shown in FIG. 2 when the cell 111 is in an abnormal state. In addition, the switches 143 and 144 are in a cutoff state (open state) as shown in FIG. 1 when the cell 111 is in a normal state, and are switched to a conducting state (closed state) as shown in FIG. 2 when the cell 111 is in an abnormal state. Note that the switch 143 is switched to a conducting state (closed state) even when the cell 112 is in an abnormal state.

[0017] The interrupter unit 14 also has switches 145, 146, and 147 for isolating the cell 112 from the electric circuit 12 when the cell 112 is in an abnormal state. The switches 145 and 146 are in a conducting state (closed state) as shown in Fig. 1 when the cell 112 is in a normal state, and are switched to a cutoff state (open state) as shown in Fig. 2 when the cell 112 is in an abnormal state. The switch 147 is in a cutoff state (open state) as shown in Fig. 1 when the cell 112 is in a normal state, and is switched to a conducting state (closed state) as shown in Fig. 2 when the cell 112 is in an abnormal state.

[0018] Furthermore, the interrupter unit 14 has switches 148 and 149 for isolating the cell 113 from the electric circuit 12 when the cell 113 is in an abnormal state. The switch 148 is in a conducting state (closed state) as shown in Fig. 1 when the cell 113 is in a normal state, and is switched to a cutoff state (open state) as shown in Fig. 2 when the cell 113 is in an abnormal state. Moreover, the switch 149 is in a cutoff state (open state) as shown in Fig. 1 when the cell 113 is in a normal state, and is switched to a conducting state (closed state) as shown in Fig. 2 when the cell 113 is in an abnormal state.

[0019] Here, in the vehicle power supply device 10 of this embodiment, as shown in FIG. 1, the voltage monitor 13 is disposed so as to detect the voltage between the cells 111, 112, ..., 113, and the cutoff unit 14 is provided with switches 141-149 so as to separate each of the cells 111, 112, ..., 113 from the electric circuit 12. Meanwhile, the number of voltage monitors 13 as the abnormality detection unit and the number of switches forming the cutoff unit 14 can be appropriately set according to the power required by the on-board load 20 when the high-voltage power supply 11 fails. For example, if the on-board load 20 requires half the power of the normal power as a fail-safe design when the high-voltage power supply 11 fails, the voltage monitor 13 and the switch of the cutoff unit 14 may be disposed at both ends (two) and the center (one) of the power supply 11.

[0020] The stop unit 15 is provided in the electric circuit 12, and independently stops the operation of the non-safety device 21, the safety device (brake, etc.) 22, the non-safety device 23, and the safety device (steering, etc.) 24, which are the in-vehicle load 20. Specifically, the stop unit 15 has a switch 151 for stopping the operation of the non-safety device 21. When the non-safety device 21 is operated (normally), the switch 151 is in an energized state (closed state) that permits the supply of power via the electric circuit 12 as shown in Fig. 1, and when the operation of the non-safety device 21 is stopped, the switch 151 is switched to a cut-off state (open state) that cuts off the supply of power via the electric circuit 12 as shown in Fig. 2.

[0021] Moreover, the stopping unit 15 has a switch 153 for stopping the operation of the non-safety device 23. When the non-safety device 23 is operated (normally), the switch 153 is in an energized state (closed state) that allows the supply of power via the electric circuit 12 as shown in Fig. 1, and when the operation of the non-safety device 23 is stopped, the switch 153 is switched to a cut-off state (open state) that cuts off the supply of power via the electric circuit 12 as shown in Fig. 2.

[0022] Here, the stopping unit 15 has switches 152, 154 capable of stopping the operation of the safety device (brake, etc.) 22 and the safety device (steering, etc.) 24. However, since the operation of the safety device (brake, etc.) 22 and the safety device (steering, etc.) 24 always takes priority, the switches 152, 154 are always maintained in an energized state (closed state) that allows the supply of power via the electric circuit 12, as shown in Figures 1 and 2. If it becomes necessary to stop the operation of the safety device (brake, etc.) 22 and the safety device (steering, etc.) 24 for some reason, the switches 152, 154 are switched to a cut-off state (open state).

[0023] The control unit 17 acquires abnormality information I indicating an abnormal state occurring in at least one of the cells 111, 112, ..., 113 from the voltage monitor 13, and controls the operation of the circuit breaker 14 and the stop unit 15. Specifically, the control unit 17 controls the switching of each of the switches 141-149 of the circuit breaker 14 from a closed state to an open state so as to disconnect at least one of the cells 111, 112, ..., 113 from the electric circuit 12 based on the abnormality information I.

[0024] Furthermore, the control unit 17 stops the operation of the non-safety devices 21 and 23 with low priority according to the priority (order of precedence) when supplying power to each of the in-vehicle loads 20 in the case where a drop in power occurs due to the disconnection of at least one of the cells 111, 112, ..., 113 by the cutoff unit 14. Specifically, the control unit 17 controls the switching of each of the switches 151 and 153 of the stop unit 15 from a closed state to an open state according to the priority. Here, the control unit 17 controls the switches 152 and 154 of the stop unit 15 to maintain a closed state so as to continue the operation of the safety device (brake, etc.) 22 and safety device (steering, etc.) 24 with high priority.

[0025] Next, the operation of the vehicle power supply device 10 will be described by taking as an example a case where an abnormality occurs in the cell 111 of the power supply 11, that is, a failure occurs in the power supply 11. As shown by a dashed-dotted circle in FIG. 2, when the voltage monitor 13 detects a voltage abnormality in the cell 111, the corresponding voltage monitor 13 outputs abnormality information I to the control unit 17. The control unit 17 switches the switches 141 and 142 of the breaker unit 14 from a closed state to an open state, and switches 143 and 144 from an open state to a closed state, so as to separate the cell 111 in which the abnormality has occurred from the electric circuit 12. As a result, the cell 111 of the power supply 11 is separated from the electric circuit 12. That is, in this case, the power supply 11 outputs power only from the normal cells 112, ..., 113.

[0026] Furthermore, in response to a failure of the power source 11, the control unit 17 cuts off the supply of power to the non-safety devices 21 and 23 in accordance with a priority (priority order) when supplying power to each of the in-vehicle loads 20, which is preset according to the power that can be output from the power source 11. Specifically, as shown by the dashed circle in Fig. 2, the control unit 17 switches the switches 151, 153 of the stop unit 15 from a closed state to an open state. As a result, the non-safety devices 21 and 23 are cut off (disconnected) from the electric circuit 12, and the supply of power is cut off, so that they stop operating.

[0027] On the other hand, although the power output from the power source 11 to the safety device (brake, etc.) 22 and the safety device (steering, etc.) 24 decreases with the separation of the cell 111, the power supply necessary for the operation from the power source 11 continues because the power supply to the non-safety device 21 and the non-safety device 23 is cut off. As a result, even if the power source 11 fails, specifically, even if the cell 111 goes into an abnormal state, the operation capability of the safety device (brake, etc.) 22 and the safety device (steering, etc.) 24, which are the in-vehicle loads 20 necessary for safely evacuating the vehicle, can be maintained. Note that, as shown in FIG. 2, even if an abnormality occurs in the cell 111, the switches 122, 123, and 124 of the electric circuit 12 are maintained in a conducting state (closed state). As a result, power is also supplied to the auxiliary power source 16, so that the auxiliary power source 16 can be charged with the power (current) supplied from the power source 11.

[0028] As can be understood from the above description, the vehicle power supply device 10 outputs and supplies electric power to each of a plurality of vehicle-mounted loads 20, that is, a non-safety device 21, a safety device (such as brakes) 22, a non-safety device 23, and a safety device (such as steering) 24, from a power supply 11 composed of a plurality of cells 111, 112, ..., 113 via an electric circuit 12. The vehicle power supply device 10 includes a voltage monitor 13 as an abnormality detection unit that detects an abnormal state of each of the cells 111, 112, ..., 113, a cutoff unit 14 that separates the cells 111, 112, ..., 113 from the electric circuit 12, a stop unit 15 that stops the operation of the non-safety device 21 and the non-safety device 23 among the vehicle-mounted loads 20, and a control unit 17 that acquires abnormality information I indicating the abnormal state from the voltage monitor 13 and controls the operation of the cutoff unit 14 and the stop unit 15, specifically, the switching between the closed state and the open state of the switches 141-149 and the switches 151, 153. Then, based on the abnormality information I, the control unit 17, for example, operates the cut-off unit 14 to disconnect the abnormal cell 111 from the electrical circuit 12, i.e., switches the switches 141-144 between closed and open states, and in the event that a drop in power occurs due to the cut-off unit 14 disconnecting the cell 111, operates the stop unit 15 to stop the operation of the non-safety device 21 and non-safety device 23 with lower priority in accordance with the priority when supplying power to each of the non-safety device 21, safety device (brakes, etc.) 22, non-safety device 23 and safety device (steering, etc.) 24, i.e., switches the switches 151, 153 from a closed state to an open state.

[0029] The vehicle power supply device 10 can identify abnormalities in the cells 111, 112, ..., 113 that make up the power supply 11, and for example, can disconnect the cell 111 that has become abnormal from the electric circuit 12. Furthermore, the vehicle power supply device 10 can stop the operation of the non-safety device 21 and the non-safety device 23, which are the in-vehicle loads 20 with low priority to supply power, when the power drops due to the disconnection of the cell 111, for example. This makes it possible to continuously supply power to the safety device (brake, etc.) 22 and the safety device (steering, etc.) 24, which are the in-vehicle loads 20 with high priority, i.e., those necessary to safely evacuate the vehicle, and maintain their operating capability. [Explanation of symbols]

[0030] 10...vehicle power supply device, 11...power supply, 111, 112, 113...cell, 12...electrical circuit, 13...voltage monitor (abnormality detection unit), 14...interruption unit, 15...stop unit, 16...auxiliary power supply, 17...control unit, 20...vehicle load, I...abnormality information

Claims

[Claim 1] A vehicle power supply device that outputs and supplies electric power to each of a plurality of vehicle-mounted loads from a power supply composed of a plurality of cells via an electric circuit, an abnormality detection unit that detects an abnormal state of each of the cells; a breaker that separates the cell from the electric circuit; A stop unit that stops the operation of the on-vehicle load; a control unit that acquires abnormality information indicating the abnormal state from the abnormality detection unit and controls the operation of the interrupting unit and the stopping unit, The control unit is activating the interrupter to disconnect the cell in the abnormal state from the electric circuit based on the abnormality information; A vehicle power supply device that, when a decrease in power occurs due to the disconnection of the cell by the cut-off unit, operates the stopping unit to stop operation of the vehicle load with a lower priority in accordance with the priority when supplying power to each of the vehicle loads.

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