Power management device for vehicle

Abstract

To provide a power management device for vehicle capable of more safely charging a low-voltage battery producing a combustible gas when charged.SOLUTION: A power management device 100 that a vehicle V is equipped with comprises: a low-voltage battery 30 which produces a combustible gas when charged; a high-voltage battery 20 which is higher in voltage than the low-voltage battery 30; a converter 50 which converts electric power supplied from the high-voltage battery 20 to the low-voltage battery 30; a position information acquisition part 60 which acquires position information related to the position of the vehicle V; and a control part 80 which controls the power supply from the high-voltage battery 20 to the low-voltage battery 30, wherein the control part 80 limits the power supply according to the position information.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] For example, an electric vehicle is equipped with a high-voltage battery that supplies power to high-voltage auxiliary devices such as a drive motor, and a low-voltage battery that supplies power to low-voltage auxiliary devices. Patent Document 1 discloses a technology for supplying power from the high-voltage battery to a lead battery, which is a low-voltage battery, using a DC-DC converter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-10280 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the power supply from the high-voltage battery to the low-voltage battery is automatically performed according to, for example, the charge amount of the low-voltage battery. On the other hand, for example, a low-voltage battery such as a lead battery may generate flammable gas during charging. In general, if the above-mentioned power supply is performed outdoors, even if flammable gas is generated, it is released into the atmosphere. However, if this power supply is performed indoors, it is considered that there is a risk that flammable gas will accumulate inside the room. Furthermore, even if it is outdoors, it may be better not to perform the above-mentioned power supply near equipment that uses fire.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a power management device for a vehicle that is capable of more safely charging a low-voltage battery that generates flammable gas when being charged. [Means for solving the problem]

[0006] The present invention has been made to solve at least some of the problems described above, and can be realized in the following aspects or application examples.

[0007] (1) The vehicle power management device of this application example is a power management device provided in a vehicle and includes a low-voltage battery that generates flammable gas when charged, a high-voltage battery that has a higher voltage than the low-voltage battery, a converter that converts the voltage of power supplied from the high-voltage battery to the low-voltage battery, a location information acquisition unit that acquires location information regarding the location of the vehicle, and a control unit that controls the supply of power from the high-voltage battery to the low-voltage battery, wherein the control unit limits the power supply in accordance with the location information.

[0008] According to this, charging of a low-voltage battery that generates flammable gas during charging can be restricted based on vehicle location information, thereby making it possible to charge a low-voltage battery installed in a vehicle more safely.

[0009] (2) The vehicle power management device of this application example is characterized in that, in the vehicle power management device of (1) above, the location information acquisition unit acquires the location information from a plurality of satellites, and the control unit limits the power supply when the number of satellites from which the location information has been acquired is equal to or less than a predetermined value.

[0010] According to this, since the power supply is limited when the number of satellites from which position information can be obtained is equal to or less than a predetermined value, the power supply can be appropriately limited even when the current position of the vehicle is unclear, and thus the low-voltage battery can be charged more safely.

[0011] (3) The vehicle power management device of this application example is characterized in that, in the power management device of (1) above, the control unit limits the power supply when the vehicle position obtained from the position information is within a pre-specified range.

[0012] According to this, since the power supply is limited when the vehicle's position is within a pre-specified range, it is possible to avoid charging the low-voltage battery in a location that is inappropriate for charging the low-voltage battery (for example, near a fire facility or indoors), and thus it is possible to charge the low-voltage battery mounted on the vehicle even more safely.

[0013] (4) The vehicle power management device according to this application example is the power management device according to (3) above, wherein the pre-specified range is a range corresponding to an interior of a vehicle.

[0014] This makes it possible to avoid charging the low-voltage battery in a location that is inappropriate for charging the low-voltage battery (specifically, indoors), and thus makes it possible to charge the low-voltage battery mounted on the vehicle even more safely.

[0015] (5) The vehicle power management device according to this application example is characterized in that, in the power management device according to (1) to (4) above, the control unit limits the power supply by making the output voltage of the converter less than a predetermined value.

[0016] According to this, the charging amount of the low-voltage battery can be kept low, and the amount of flammable gas generated by charging the low-voltage battery can be reduced, so that the low-voltage battery mounted on the vehicle can be charged more safely.

[0017] (6) In the power management device for a vehicle according to this application example, in the power management device according to (5) above, the predetermined value is a voltage of the low-voltage battery when no load is applied or when a low load is applied.

[0018] This makes it possible to eliminate the influence of various loads on the low-voltage battery and set an upper limit for the converter output voltage, thereby making it possible to charge the low-voltage battery mounted on the vehicle even safer.

[0019] (7) The vehicle power management device of this application example is characterized in that, in the power management device according to (1) to (6) above, the control unit limits the power supply by prohibiting the converter from supplying power from the high-voltage battery to the low-voltage battery.

[0020] This allows the charging of the low-voltage battery to be suspended until the vehicle moves to a new location, thereby making it possible to charge the low-voltage battery mounted on the vehicle even safer.

[0021] In this way, according to the present invention, it is possible to provide a power management device that can more safely charge a low-voltage battery that generates flammable gas when being charged. [Brief description of the drawings]

[0022] [Figure 1] 1 is an overall configuration diagram showing an embodiment of a power management device for a vehicle according to the present invention; [Diagram 2] 4 is a flowchart for explaining the operation of the power management device of the vehicle shown in FIG. [Diagram 3] FIG. 3 is an explanatory diagram for supplementarily explaining the flowchart shown in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Next, an embodiment of a power management device for a vehicle according to the present invention will be described with reference to Figs. 1 to 3 as appropriate.

[0024] First, the configuration of the vehicle power management device according to this embodiment will be described. FIG. 1 is an overall configuration diagram of the vehicle power management device according to this embodiment. As shown in FIG. 1, the power management device 100 according to this embodiment is provided in an electric vehicle such as an electric car or a hybrid car. The vehicle V of this embodiment is an electric truck, and is a plug-in electric vehicle that can be charged by an external charger (not shown). The power management device 100 includes a drive mechanism 10, a high-voltage battery 20, a low-voltage battery 30 (e.g., a lead battery), electrical equipment 40, a DC-DC converter 50 (converter), a GPS receiver 60 (position information acquisition unit), an operation unit 70, and a control unit 80 (VCU).

[0025] The drive mechanism 10 includes a motor 11 for driving the vehicle V, and a transmission 12 (gearbox) that adjusts the driving force generated by the motor 11 to an appropriate torque and transmits it to the differential mechanism D. The torque transmitted to the differential mechanism D is transmitted to the wheels R1 and R2 via the drive shafts A1 and A2, respectively.

[0026] The high-voltage battery 20 is electrically connected to the motor 11 of the drive mechanism 10 and is a relatively high-voltage, large-capacity battery for supplying power to the motor 11. The high-voltage battery 20 is, for example, a 200V lithium-ion battery. In the vehicle V of this embodiment, the high-voltage battery 20 can be charged from an external charger, and the high-voltage battery 20 can also be discharged to the external charger. In other words, the vehicle V of this embodiment is a vehicle capable of so-called V2H (Vehicle to Home).

[0027] The low-voltage battery 30 is a battery with a lower voltage than the high-voltage battery 20. The voltage of the low-voltage battery 30 in this embodiment is 24 V. The low-voltage battery 30 may be any battery with a lower voltage than the high-voltage battery 20, for example, a 12 V lead battery.

[0028] The electrical equipment 40 is a component that is electrically connected to the low-voltage battery 30 and is driven by the power of the low-voltage battery 30, and is, for example, low-voltage auxiliary equipment of the vehicle V such as headlights, turn signals, audio, etc.

[0029] The DC-DC converter 50 is electrically connected between the high-voltage battery 20 and the low-voltage battery 30, and is a converter that converts (specifically, reduces) the voltage of the power supplied from the high-voltage battery 20 to the low-voltage battery 30.

[0030] The GPS receiver 60 is a location information acquisition unit mounted on the vehicle V, and is configured to be able to acquire information about the location of the vehicle V on which the power management device 100 is mounted by receiving radio waves r1-r4 transmitted from a plurality of GPS satellites s1-s4. Specifically, the GPS receiver 60 is configured to be able to acquire location information about the location of the vehicle V by calculating the distance between the vehicle V and each of the plurality of GPS satellites s1-s4. Note that, although only four GPS satellites are shown in this embodiment for the sake of simplicity of explanation, there are five or more GPS satellites, and the GPS receiver 60 can also receive radio waves from five or more GPS satellites.

[0031] The operation unit 70 is a part that accepts operations on the control unit 80 by the driver of the vehicle V or the like, and is, for example, a touch panel, a switch, or the like that can be operated by the driver of the vehicle V. In this embodiment, a designated range, which will be described later, can be set in the control unit 80 via the operation unit 70. The designated range is, for example, a range in which caution is required when charging the low-voltage battery 30 because it is a range in the vicinity of a fire, a range that corresponds (applies) to a room, or the like.

[0032] The control unit 80 (VCU: Vehicle Control Unit) is a computer that performs various controls of the vehicle V, and is connected to the high-voltage battery 20, the low-voltage battery 30, the DC-DC converter 50, the GPS receiving unit 60, and the operation unit 70 so that information can be exchanged between them. The control unit 80 includes a CPU, a main memory device, an auxiliary memory device which is a non-transitory tangible medium, and an interface, all of which are not shown.

[0033] Specifically, the control unit 80 can acquire information such as the charge amount and voltage of each battery, and the output and input currents from the high-voltage battery 20 and the low-voltage battery 30. The control unit 80 can also acquire information such as the input voltage before voltage conversion by the DC-DC converter 50 and the output voltage after voltage conversion from the DC-DC converter 50. The control unit 80 can also acquire location information of the vehicle V acquired by the GPS receiver unit 60 from the GPS receiver unit 60, and can also acquire operation information accepted by the operation unit 70 from the operation unit 70.

[0034] The control unit 80 of this embodiment can control the power supply from the high-voltage battery 20 to the low-voltage battery 30 via the DC-DC converter 50 according to the position information acquired by the GPS receiving unit 60. Specifically, the control unit 80 restricts (including prohibits) the charging of the low-voltage battery 30 in an indoor environment where flammable gas generated by charging the low-voltage battery 30 is likely to fill the room, and in an environment where there is a fire nearby that may ignite the flammable gas. The environment where there is a fire nearby is, for example, near a smoking area provided in a parking facility of the vehicle V, near a boiler facility, etc. Specific control contents by the control unit 80 will be described later in the description of the flowchart shown in FIG. 2. In addition, when the vehicle V is connected to an external charger, the control unit 80 can also issue a charging instruction to a charging circuit (not shown) of the vehicle V to charge the high-voltage battery 20 from the external charger, or issue a discharging instruction to the charging circuit to discharge the high-voltage battery 20 to the external charger.

[0035] Next, the operation of the power management device for a vehicle according to this embodiment will be described. Fig. 2 is a flowchart for explaining the operation of the power management device 100 shown in Fig. 1. This flowchart is based on the premise that the vehicle V is in a key-off state (i.e., the motor 11 is not driven). In this operation, some of steps S1 to S7 shown in Fig. 2 are selectively performed. Fig. 3 is an explanatory diagram for supplementary explanation of the flowchart shown in Fig. 2.

[0036] In step S1, the GPS receiver 60 acquires position information of the vehicle V. Specifically, the GPS receiver 60 attempts to receive radio waves r1-r4 transmitted from GPS satellites s1-s4, calculates the number of GPS satellites s1-s4 from which signals have been received, and identifies the current position of the vehicle V if the number of GPS satellites s1-s4 from which signals have been received is three or more.

[0037] Next, in step S2, the control unit 80 determines whether the number of GPS satellites s1-s4 received by the GPS receiving unit 60 exceeds a predetermined value N (where N is 2 or more). If the control unit 80 determines that the number exceeds the predetermined value N (i.e., if step S2 is Yes), it proceeds to step S3, and if the control unit 80 determines that the number does not exceed the predetermined value N (i.e., is equal to or less than the predetermined value N) (i.e., if step S2 is No), it proceeds to step S4.

[0038] Here, a supplementary explanation will be given regarding step S2. If step S2 is Yes, i.e., if the number of GPS satellites s1 to s4 that can be received by the GPS receiving unit 60 is large, it is considered that the vehicle V is outdoors, which is an environment in which it is easy to receive radio waves, as shown in Fig. 3(a). On the other hand, if step S2 is No, i.e., if the number of GPS satellites s1 to s4 that can be received by the GPS receiving unit 60 is small, it is considered that the vehicle V is indoors, which is an environment in which it is difficult to receive radio waves, as shown in Fig. 3(b).

[0039] In step S3, the control unit 80 determines whether the current position of the vehicle V acquired by the GPS receiving unit 60 is outside a designated range designated in advance by the driver of the vehicle V. The designated range here is a range where caution is required when charging the low-voltage battery 30 due to reasons such as a range where there is a fire nearby or a range corresponding to an indoor space. If the control unit 80 determines that it is outside the designated range (i.e., if step S3 is Yes), it proceeds to step S5, and if it determines that it is not outside the designated range (i.e., if it is within the designated range) (i.e., if step S3 is No), it proceeds to step S4.

[0040] Here, a supplementary explanation will be given regarding step S3. If step S3 is Yes, i.e., if the current position of the vehicle V is outside the designated range, it is considered that the vehicle V is within a range in which the low-voltage battery 30 can be safely charged, as shown in Fig. 3(c). On the other hand, if step S3 is No, i.e., if the current position of the vehicle V is within the designated range, it is considered that the current position of the vehicle V is within a range in which caution is required when charging the low-voltage battery 30, as shown in Fig. 3(d).

[0041] In step S4, the control unit 80 judges whether or not a charge instruction has been issued for the high-voltage battery 20, or whether or not a discharge instruction has been issued for the high-voltage battery 20 (hereinafter referred to as a charge / discharge instruction). If a charge / discharge instruction has been issued (i.e., if step S4 is Yes), the control unit 80 proceeds to step S6, and if a charge / discharge instruction has not been issued (i.e., if step S4 is No), the control unit 80 proceeds to step S7.

[0042] In step S5, the control unit 80 charges the low-voltage battery 30 by supplying power from the high-voltage battery 20 to the low-voltage battery 30 without any particular restrictions. Note that the control unit 80 may perform control so as not to charge the low-voltage battery 30 if the power of the low-voltage battery 30 is sufficient (for example, if the voltage is equal to or higher than a predetermined voltage).

[0043] In step S6, the control unit 80 charges the low-voltage battery 30 by supplying power from the high-voltage battery 20 to the low-voltage battery 30 while limiting the DC-DC output voltage to less than a predetermined value V1. The predetermined value V1 here is the voltage of the low-voltage battery 30 when it is unloaded or under a low load. The low load state is, for example, a state for operating the control unit 80 (ECU) of the vehicle V. When the power supply to the electrical equipment 40 is turned off, for example, immediately after the key-off of the vehicle V, the control unit 80 determines that the low-voltage battery 30 is under no load or low load, measures the voltage of the low-voltage battery 30 at this time, and stores it as the predetermined value V1. In this way, the control unit 80 limits the power supply to the low-voltage battery 30.

[0044] In step S7, the control unit 80 prohibits charging of the low-voltage battery 30 for a certain period of time, thereby limiting the power supply to the low-voltage battery 30. The certain period of time here may be, for example, a period until the GPS receiving unit 60 acquires new position information of the vehicle V, or a predetermined time such as 30 minutes or 1 hour.

[0045] According to the vehicle power management device of this embodiment, in steps S6 and S7 shown in FIG. 2, charging of the low-voltage battery 30 can be limited based on the position information of the vehicle V, so that charging of the low-voltage battery 30 installed in the vehicle V can be carried out more safely.

[0046] Furthermore, since the power supply is limited when the number of GPS satellites s1-s4 from which position information could be obtained is equal to or less than a predetermined value N (when step S2 in FIG. 2 is No), even if the current position of the vehicle V is unclear, it is possible to estimate that the vehicle V is in an indoor environment from the number of GPS satellites that are the source of receivable radio waves, and to appropriately limit the power supply. Therefore, the low-voltage battery 30 mounted on the vehicle V can be charged more safely.

[0047] Furthermore, since the power supply is limited when the position of the vehicle V is within a pre-specified range (when step S3 shown in FIG. 2 is No), it is possible to avoid charging the low-voltage battery 30 in a location that is inappropriate for charging the low-voltage battery 30 (for example, near a fire facility or indoors). Therefore, it is possible to charge the low-voltage battery 30 mounted on the vehicle V even more safely.

[0048] 2, the control unit 80 limits the power supply to the low-voltage battery 30 by setting the output voltage of the DC-DC converter 50 to less than a predetermined value V1, so that the charge amount of the low-voltage battery 30 can be kept low during charging and discharging between the high-voltage battery 20 and the external charger, and the amount of flammable gas generated by charging the low-voltage battery 30 can be suppressed. Therefore, the low-voltage battery 30 mounted on the vehicle V can be charged even more safely.

[0049] In addition, since the predetermined value V1 here is the voltage of the low-voltage battery 30 when no load or a low load is applied, it is possible to set an upper limit value for the output voltage of the DC-DC converter 50 while eliminating the influence of various loads of the vehicle V on the low-voltage battery 30. Therefore, the low-voltage battery 30 mounted on the vehicle V can be charged even more safely.

[0050] 2, the control unit 80 prohibits the DC-DC converter 50 from supplying power from the high-voltage battery 20 to the low-voltage battery 30, thereby suspending charging of the low-voltage battery 30 for a certain period of time, such as until the vehicle V moves to a new location. This makes it possible to charge the low-voltage battery 30 mounted on the vehicle V even safer.

[0051] In this way, according to the vehicle power management device of this embodiment, it is possible to limit charging of the low-voltage battery 30 in rooms with poor ventilation and in places where there is fire, thereby making it possible to charge the low-voltage battery 30 installed in the vehicle V more safely.

[0052] This concludes the description of the embodiment of the present invention, but the aspects of the present invention are not limited to this embodiment.

[0053] In the flowchart shown in Fig. 2, both steps S2 and S3 are provided as operation steps of the vehicle power management device 100 shown in Fig. 1, but only one of these steps may be provided. When only step S2 is provided, if step S2 is Yes, the process proceeds to step S6. When only step S3 is provided, the current position of the vehicle V is identified in step S1, and when step S1 is completed, the process proceeds to step S3.

[0054] In the above embodiment, a lead battery is given as an example of the low-voltage battery 30 that generates a flammable gas, but a battery other than a lead battery may be used as the low-voltage battery 30 as long as it generates a flammable gas when charged. Furthermore, a lead battery generates hydrogen gas, which is a flammable gas, when charged, but the low-voltage battery 30 may be one that generates a flammable gas other than hydrogen gas when charged. [Explanation of symbols]

[0055] 10 Drive mechanism 11 Motor 12. Transmission 20 High Voltage Battery 30 Low voltage battery (e.g. lead battery) 40 Electrical Equipment 50 DC-DC converter (converter) 60 GPS receiver (location information acquisition unit) 70 Operation section 80 Control Unit (VCU) 100 Power management equipment A1, A2 drive shaft D Differential mechanism R1, R2 wheels r1~r4 Radio waves s1~s4 satellite V Vehicle

Claims

1. A power management device provided in a vehicle, A low-voltage battery that generates flammable gases when charged; a high-voltage battery having a higher voltage than the low-voltage battery; a converter that converts the voltage of the power supplied from the high voltage battery to the low voltage battery; a location information acquisition unit that acquires location information relating to a location of the vehicle; a control unit that controls power supply from the high-voltage battery to the low-voltage battery, The power management device for a vehicle, wherein the control unit limits the power supply in accordance with the position information.

2. the location information acquisition unit acquires the location information from a plurality of satellites, 2. The power management device for a vehicle according to claim 1, wherein the control unit limits the power supply when the number of satellites from which the position information can be obtained is equal to or less than a predetermined value.

3. The power management device for a vehicle according to claim 1 , wherein the control unit limits the power supply when the position of the vehicle acquired from the position information is within a predesignated range.

4. 4. The power management device for a vehicle according to claim 3, wherein the pre-specified range is a range corresponding to an interior of a vehicle.

5. The power management device for a vehicle according to claim 1 , wherein the control unit limits the power supply by making the output voltage of the converter less than a predetermined value.

6. 6. The vehicle power management device according to claim 5, wherein the predetermined value is a voltage of the low-voltage battery when no load is applied or when a low load is applied.

7. 2. The power management device for a vehicle according to claim 1, wherein the control unit limits the power supply by prohibiting the converter from supplying power from the high-voltage battery to the low-voltage battery.

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