JP6513516B2 - Power supply and control method of power supply - Google Patents

Description

  The present invention relates to a power supply device and a control method of the power supply device.

  In recent years, vehicle by wire technology has become widespread. In the by-wire technology, operations such as an accelerator and a brake are performed not by mechanical transmission but by transmission by electrical signals.

  With the proliferation of such by-wire technology, the reliability of the battery, which is the source for generating electrical signals, is becoming more important.

  Patent documents 1-3 exist as a prior art which improves the reliability of a power supply. Here, Patent Documents 1 and 2 disclose a technique for improving the reliability of the power supply of a vehicle by providing an electric double layer capacitor and supplying power from the electric double layer capacitor to a load.

  Patent Document 3 discloses a technique for improving the reliability of the power supply of a vehicle by providing a sub-battery in addition to the main battery and supplying power from the sub-battery when the main battery does not operate normally.

JP, 2006-327568, A JP 2004-322987 A Unexamined-Japanese-Patent No. 2004-289892

  By the way, in the techniques disclosed in Patent Literatures 1 and 2, the size of the electric double layer capacitor is larger than that of the secondary battery, so there is a problem that it is difficult to secure a mounting place.

  Moreover, in the technique disclosed in Patent Document 3, there is a problem that it takes time to be able to supply power from the sub-battery since the sub-battery is charged by the alternator.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a power supply device and a control method of the power supply device, which can easily provide a power quickly because it is easy to secure a mounting location.

In order to solve the above problems, the present invention is a power supply device mounted on a vehicle and supplying power source power to a load, provided separately from the main battery mounted on the vehicle, and having an electric capacity than the main battery A charging means for charging the sub-battery by the sub-battery having a small power, a boosting means for boosting the power output from the main battery, and the power boosted by the boosting means; Control means for performing control to charge the sub-battery by the charging means , wherein the control means is a case where the engine of the vehicle is stopped, and the door lock of the vehicle is released When the door is opened, the sub-battery can be driven by a higher voltage than when the vehicle's engine is simply stopped. It executes control to charge, characterized in that.
According to such a configuration, it is possible to easily secure the mounting location and quickly provide power.

Further, according to the present invention, the control means performs control of charging the sub-battery when the engine of the vehicle is stopped and the charging rate of the sub-battery becomes equal to or less than a predetermined threshold value. It is characterized by carrying out.
Further, according to the present invention, the boosting unit stops the boosting operation after the engine of the vehicle is started, and the charging unit charges the sub-battery by the power output from the alternator. I assume.

Further, the present invention is characterized in that the control means does not execute charging of the sub-battery when the charging rate of the main battery is equal to or less than a predetermined value.
Further, the present invention is characterized in that the main battery and the sub-battery are both secondary batteries.

Further, the present invention is characterized in that the main battery is accommodated in a bonnet in front of the vehicle, and the sub-battery is accommodated at a place other than the bonnet.

Further, the present invention is a power supply device mounted on a vehicle and supplying power source power to a load, the sub-battery being provided separately from the main battery mounted on the vehicle and having a smaller electric capacity than the main battery In the control method of the power supply device, the boosting step of boosting the power output from the main battery, the charging step of charging the sub-battery with the power boosted in the boosting step, and the stopping of the engine of the vehicle And a control step of performing control to charge the sub-battery by the charging step , wherein the control step is a case where the engine of the vehicle is stopped and locking of the door of the vehicle When the vehicle's engine is simply shut off when the door is released or the door is opened The base and high voltage, performs control for charging the sub-battery, wherein the.
According to such a method, it is possible to easily secure the mounting location and quickly provide power.

  According to the present invention, it is possible to provide a power supply device and a control method of the power supply device capable of providing power quickly, while easily securing a mounting location.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structural example of the power supply system of the vehicle which has a power supply device which concerns on 1st Embodiment of this invention. It is a figure which shows the detailed structural example of the auxiliary power supply part shown in FIG. It is a figure for demonstrating the operation | movement of 1st Embodiment of this invention. It is a flowchart which shows an example of the process performed in 1st Embodiment of this invention. It is a figure for demonstrating the operation | movement of 2nd Embodiment of this invention. It is a flowchart which shows an example of the process performed in 2nd Embodiment of this invention.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of First Embodiment of the Present Invention FIG. 1 is a diagram showing a power supply system of a vehicle having a power supply device according to a first embodiment of the present invention. As shown in this figure, the power supply system of the vehicle includes a control unit 10, a starter motor 11 for starting the engine 12, an alternator 13 driven by the engine 12, a main battery 14, a voltage sensor 15, a current sensor 16, and a temperature sensor 17. , An auxiliary power supply unit 18 and loads 20 to 22.

  Here, the control unit 10 refers to the outputs of the voltage sensor 15, the current sensor 16, the temperature sensor 17 and the like, detects the state of the main battery 14, and controls the generated voltage of the alternator 13 to control the main battery Control the charge status of 14.

  The starter motor 11 is an electric motor which cranks the engine 12 and starts it by the electric power stored in the main battery 14. The engine 12 is constituted by, for example, a reciprocating engine or a rotary engine, and is started by the starter motor 11 to drive the vehicle and rotationally drive the alternator 13.

  The alternator 13 is driven by the engine 12, generates AC power, converts it into DC power by the rectification circuit, and charges the main battery 14 and a sub-battery 187 described later.

  The main battery 14 is composed of, for example, a secondary battery such as a lead storage battery, a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery, is charged by the alternator 13 and drives the starter motor 11 to start the engine 12 In addition, power is supplied to the loads 20 to 22 through the auxiliary power supply unit 18.

  The voltage sensor 15 detects the terminal voltage of the main battery 14 and notifies the control unit 10 of it. The current sensor 16 detects the current flowing through the main battery 14 and notifies the control unit 10 of the current. The temperature sensor 17 detects the main battery 14 itself or the ambient temperature around it and notifies the control unit 10 of it.

  The auxiliary power supply unit 18 has a sub battery 187 as described later, and supplies power from the main battery 14 or the sub battery 187 to the loads 20 to 22 according to the state of the vehicle.

  The load 20 is a normal load, and includes, for example, various lights, a defogger, a wiper, and a blower motor for air conditioning. The load 21 is a load that is susceptible to fluctuations in the power supply voltage, and for example, car audio and navigation systems that are prone to output power fluctuations as noise, and various ECUs (Electric Control Units) that are prone to reset due to voltage fluctuations. Composed of The load 22 is a load that needs to be backed up when a failure occurs in the main battery 14 or the alternator 13 (when a power supply failure occurs). For example, the electronically controlled brake and position information etc. It is comprised by the apparatus etc. which notify.

  FIG. 2 is a view showing a detailed configuration example of the auxiliary power supply unit 18 shown in FIG. As shown in FIG. 2, the auxiliary power supply unit 18 includes an auxiliary power supply control unit 181, relays 182 to 185, a DC / DC converter 186, a sub battery 187, a voltage sensor 188, a current sensor 189, and a temperature sensor 190. ing.

  Here, the auxiliary power supply control unit 181 controls each unit of the auxiliary power supply unit 18 based on the control signal from the control unit 10 and the detection results of the voltage sensor 188, the current sensor 189, the temperature sensor 190, and the like. .

  The relays 182 to 185 are formed of, for example, an electromagnetic relay or a semiconductor relay, and are turned on or off according to the control of the auxiliary power supply control unit 181 to control the supply of power to the loads 20 to 22.

  When charging the sub-battery 187, the DC / DC converter 186 supplies the power output from the relay 185 to the sub-battery 187. Further, when discharging from the sub battery 187, the power output from the sub battery 187 is supplied to the relay 185.

  Sub battery 187 is formed of a secondary battery such as a lead storage battery, a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery, for example, and is formed of a battery independent of main battery 14. The battery also has a small electric capacity. More specifically, while the main battery 14 has a capacity of about several tens of Ah, the sub-battery 187 has a capacity of several Ah to several dozen Ah. Further, the main battery 14 is accommodated in the bonnet in front of the vehicle, but the sub-battery 187 is accommodated not in the bonnet but in, for example, a spare tire storage portion or the like in the rear of the vehicle. Of course, although it may be accommodated in other places, in order to extend the life of the sub-battery 187, a place with a small temperature change is desirable. Also, by arranging the battery in a different place from the main battery 14, for example, even if one of them is broken, power can be supplied from the other even in the event of a crash, and in view of risk distribution, these are arranged in different places. Is desirable.

  The voltage sensor 188 detects the terminal voltage of the sub battery 187 and notifies the auxiliary power control unit 181 of the detection. The current sensor 189 detects the current flowing through the sub battery 187 and notifies the auxiliary power control unit 181 of the current. The temperature sensor 190 detects the temperature of the sub battery 187 itself or the surrounding environment, and notifies the auxiliary power control unit 181 of the temperature.

(B) Description of Operation of the First Embodiment of the Present Invention Next, the operation of the first embodiment of the present invention will be described. FIG. 3 is a diagram showing the correspondence between the states of the vehicle and the states of the relays 182 to 185 and the DC / DC converter 186. As shown in FIG. The operation of the embodiment of the present invention will be described below with reference to FIG.

  First, when the main battery 14 and the alternator 13 are normal and the charging rate (SOC) of the sub battery 187 exceeds a predetermined threshold, the auxiliary power control unit 181 determines that the normal time is reached. When it is determined that the operation is normal, the auxiliary power control unit 181 turns on the relays 182 to 184 and turns off the relay 185 as shown in FIG. Also, the DC / DC converter 186 is put in the stop state. As a result, the supply of power from the sub-battery 187 to the loads 20 to 22 is stopped, and power is supplied from the main battery 14 or the alternator 13 to the loads 20 to 22. As described above, since power is not supplied from the sub battery 187 to the load when the main battery 14 and the like are normal, the reduction of the charging rate of the sub battery 187 can be prevented. It may be determined that the main battery 14 and the alternator 13 are normal and the sub battery 187 is “full charge” when it is normal.

  Next, if the driver approaches and releases the door lock of the vehicle while the vehicle is stopped, the auxiliary power control unit 181 determines that the door lock is released. When it is determined that the door lock is released, the auxiliary power control unit 181 detects the charging rate of the sub-battery 187, and as shown in FIG. 3 when the charging rate is less than a predetermined threshold (for example, 80%). The relays 182 and 185 are turned on and the relays 183 and 184 are turned off. Also, the DC / DC converter 186 is put in a charging operation state. As a result, no power is supplied to the loads 21 and 22. Also, the DC / DC converter 186 boosts the voltage of about 12 V supplied from the main battery 14 to, for example, about 16 V, and supplies it to the sub-battery 187. As a result, sub battery 187 can be charged in a short time.

  Next, when the engine 12 is started by the starter motor 11, the auxiliary power control unit 181 determines that it is at the start time. In addition, not only when the driver gets on the vehicle and starts the engine 12 for the first time by the starter motor 11 but also at the time of return from so-called idling stop where the engine 12 is stopped when the engine 12 is idling Also when starting the engine 12, it shall be included at the time of starting. When it is determined that the engine is started, the auxiliary power control unit 181 turns off the relay 182 and turns on the relays 183 to 185, as shown in FIG. Further, the DC / DC converter 186 is brought into the stop state (through state). As a result, power is supplied to the load 20 from the main battery 14, and power is supplied to the loads 21 and 22 from the sub-battery 187 via the DC / DC converter 186. As a result, at start-up, power is supplied from the main battery 14 to the normal load 20, and power from the sub-battery 187 is applied to the load 21 susceptible to changes in the power supply voltage and the load 22 requiring backup. Thus, the load 21 can be stably operated and the load 22 can be reliably backed up. Also, by supplying power to the load 20 from the main battery 14, it is possible to prevent the decrease in the charging rate of the sub-battery 187. When the charging rate of sub battery 187 is low, sub battery 187 is charged with the voltage boosted by DC / DC converter 186 by the process at the time of door lock release described above. Regardless of the load, stable power can be supplied to the loads 21 and 22.

  Next, when it is determined that the charging rate (SOC) of the sub battery 187 is less than or equal to a predetermined threshold while the engine 12 is operating, the auxiliary power control unit 181 determines that the sub battery is being charged. As a result, the auxiliary power supply control unit 181 turns on all the relays 182 to 185 and stops the DC / DC converter 186 (through state) to supply the power supplied from the alternator 13 to the sub-battery 187. . As a result, power is supplied from the main battery 14 to the loads 20 to 22. The sub battery 187 is supplied from the alternator 13 and charged by the power passing through the DC / DC converter 186. Sub battery 187 may be supplied from alternator 13 and charged by the electric power boosted by DC / DC converter 186. According to such a configuration, charging can be performed in a short time.

  Next, when an abnormality occurs in the main battery 14 or the alternator 13 and power can not be supplied from the main battery 14 or when the charging rate of the main battery 14 is not sufficient, the auxiliary power control unit 181 It is determined that it is at the time of failure. At the time of power failure, the auxiliary power control unit 181 turns off the relays 182 and 183 and turns on the relays 184 and 185. In addition, the DC / DC converter 186 is brought into the stop state (through state). As a result, power is supplied to the load 22 from the sub-battery 187 via the DC / DC converter 186, and power is not supplied to the loads 20 and 21. As a result, since power is supplied from the sub-battery 187 to the load 22 that needs to be backed up, the load 22 can be reliably backed up. In addition, by stopping the operations of loads 20 and 21, the load on sub battery 187 can be reduced.

  As described above, according to the embodiment of the present invention, when the door lock of the vehicle is released, the power of the main battery 14 is boosted by the DC / DC converter 186 to charge the sub-battery 187. The sub battery 187 can be charged quickly before the start of the engine 12. Therefore, when starting the engine 12, stable power can be supplied to the loads 21 and 22. Further, since sub battery 187 is charged by the power supplied from alternator 13 after engine 12 is started, the power corresponding to the power consumed by loads 21 and 22 when engine 12 is started. The sub battery 187 can be charged.

  Next, with reference to FIG. 4, an example of the flow of processing executed in the first embodiment shown in FIG. 1 and FIG. 2 will be described. When the process of the flowchart shown in FIG. 4 is performed, the following steps are performed.

  In step S10, the auxiliary power control unit 181 inquires of the control unit 10 whether or not the door lock is released, and as a result, when it is determined that the door lock is released (step S10: Yes), the process proceeds to step S11. The process proceeds to step S15 if otherwise (step S10: No).

  In step S11, the auxiliary power control unit 181 detects the state of the sub battery 187. That is, the auxiliary power supply control unit 181 pulse discharges the sub-battery 187, detects the voltage and current at that time by the voltage sensor 188 and the current sensor 189, calculates the internal impedance, and calculates the charging rate based on the calculated internal impedance. Find (SOC).

  In step S12, the auxiliary power control unit 181 determines whether charging is necessary based on the charging rate of the sub battery 187 detected in step S11. For example, if the charging rate of the sub battery 187 detected in step S11 is, for example, 80% or less (step S12: Yes), it is determined that charging is necessary, and the process proceeds to step S13, otherwise (step S12) : No, the process proceeds to step S14. In addition, you may make it determine not whether it is 80% or less, but based on whether it is a full charge.

  In step S13, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the state when the door lock is released. That is, the auxiliary power supply control unit 181 turns on the relays 182 and 185, turns off the relays 183 and 184, and sets the DC / DC converter 186 in an operating state (charging state). As a result, no power supply power is supplied to the loads 20 to 22, and the power supplied from the main battery 14 is boosted and supplied to the sub battery 187 by the DC / DC converter 186. Thereby, sub battery 187 is charged quickly.

  In step S14, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the normal state. That is, the auxiliary power supply control unit 181 turns on the relays 182 to 184, turns off the relay 185, and sets the DC / DC converter 186 in a stopped state (through state). As a result, the supply of power from the sub-battery 187 is stopped, and the loads 20 to 22 are supplied with power from the main battery 14.

  In step S15, the auxiliary power control unit 181 inquires of the control unit 10 about the state of the main battery 14. As a result, the control unit 10 detects the state of the main battery 14 with reference to the output of the voltage sensor 15 or the like, and notifies the auxiliary power control unit 181. More specifically, control unit 10 detects the terminal voltage and charging rate of main battery 14 and notifies auxiliary power control unit 181.

  In step S16, the auxiliary power supply control unit 181 determines whether or not the power supply failure state is present based on the state of the main battery 14 detected in step S15, and determines that the power supply failure state is present (step S16). If yes, the process proceeds to step S26. If not (step S16: No), the process proceeds to step S17. For example, when the terminal voltage of the main battery 14 detected by the voltage sensor 15 is lower than, for example, a predetermined threshold (for example, 10 V), it is determined that the power is in a power failure state, and the process proceeds to step S26.

  In step S17, the auxiliary power supply control unit 181 inquires of the control unit 10 whether or not an instruction to start the engine 12 is given (for example, an ignition switch not shown is operated), and as a result, starts the engine 12 If it is determined that an instruction has been given (step S17: Yes), the process proceeds to step S18. Otherwise (step S17: No), the process returns to step S10 and the same process as described above is repeated.

  In step S18, the auxiliary power supply control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the state at the start. That is, the auxiliary power control unit 181 turns the relay 182 off, turns the relays 183 to 185 on, and sets the DC / DC converter 186 to the stop state (through state). Thus, power is supplied to the load 20 from the main battery 14, and power is supplied to the loads 21 and 22 from the sub-battery 187. As a result, when the engine 12 is cranked by the starter motor 11, the voltage of the main battery 14 becomes unstable, and the operations of the loads 21, 22 can be prevented from becoming unstable.

  In step S19, the auxiliary power control unit 181 inquires of the control unit 10 whether or not starting of the engine 12 is completed, and as a result, when it is determined that starting of the engine 12 is completed (step S19: Yes) The process proceeds to step S20, and otherwise (step S19: No), the process returns to step S18 to repeat the same process as described above.

  In step S20, the auxiliary power control unit 181 determines whether or not charging of the sub-battery 187 is necessary, and if it is determined that charging is necessary (step S20: Yes), the process proceeds to step S21, otherwise ( In step S20: No), the process proceeds to step S22. For example, when the charging rate of the sub battery 187 is equal to or less than a predetermined threshold (for example, 90%), it is determined as Yes, and the process proceeds to step S21.

  In step S21, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the state at the time of sub battery charging. That is, the auxiliary power supply control unit 181 turns on all the relays 182 to 185 and sets the DC / DC converter 186 in the operating state (boosted state). Thereby, sub battery 187 is supplied from alternator 13 and charged by the power boosted by DC / DC converter 186.

  In step S22, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the normal state. That is, the auxiliary power supply control unit 181 turns on the relays 182 to 184, turns off the relay 185, and sets the DC / DC converter 186 in a stopped state (through state). As a result, the supply of power from the sub-battery 187 is stopped, and the loads 20 to 22 are supplied with power from the main battery 14.

  In step S23, the auxiliary power control unit 181 requests the control unit 10 to detect the state of the main battery 14. As a result, the control unit 10 detects the terminal voltage of the main battery 14 by the voltage sensor 15 and detects the charging rate of the main battery 14.

  In step S24, the auxiliary power control unit 181 determines whether or not the main battery 14 is in the power failure state based on the detection result in step S19, and determines that the power failure state is (step S24). If yes, the process proceeds to step S26. If not (step S24: No), the process proceeds to step S25. For example, when the terminal voltage of the main battery 14 detected by the voltage sensor 15 is lower than a predetermined threshold (for example, 10 V), it is determined that the power is in a power failure state, and the process proceeds to step S26.

  In step S25, the auxiliary power control unit 181 determines whether or not the engine 12 has been stopped, and if it is determined that the engine 12 has been stopped (step S25: Yes), the process returns to step S10 and the same processing as described above is performed. Repeatingly, in other cases (step S25: No), the process returns to step S18 and repeats the same process as the above-mentioned case.

  In step S26, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the state at the time of power failure. That is, the auxiliary power control unit 181 turns off the relays 182 and 183, turns on the relays 184 and 185, and sets the DC / DC converter 186 in a stopped state (through state). Thus, power is supplied to the loads 21 and 22 from the sub-battery 187, and power is supplied to the load 20 from the main battery 14.

  As described above, according to the flowchart shown in FIG. 4, when the door lock is released and the charging rate of sub battery 187 is low, DC / DC converter 186 boosts the power of main battery 14 Since the sub battery 187 is charged, the sub battery 187 can be charged quickly. In addition, after starting the engine 12, the power of the alternator 13 is boosted by the DC / DC converter 186 to charge the sub-battery 187. Therefore, when the engine 12 is started, the loads 21 and 22 are consumed. Power can be replenished quickly.

(C) Description of Second Embodiment Next, a second embodiment of the present invention will be described. The second embodiment of the present invention is similar in configuration to FIGS. 1 and 2, but differs in the processing and operations performed. Therefore, in the following, with reference to FIG. 5 and FIG. 6, the process and operation performed in the second embodiment will be described.

  FIG. 5 is a diagram for explaining the operation of the second embodiment. In FIG. 5, the description of the same parts as those in FIG. 3 will be omitted. In FIG. 5, in comparison with FIG. 3, the second door lock release time from the top is changed to the sub battery charge time (during stop), and it is clarified that the second from the bottom is the operation during traveling. In order to turn on the sub-battery charge (while driving) has been changed. Except this, it is the same as FIG.

  Here, when it is determined that the charging rate of sub battery 187 is equal to or less than a predetermined threshold when the vehicle is stopped with the engine 12 stopped, the auxiliary power control unit 181 charges the sub battery (during parking) It is determined that When it is determined that the sub-battery is charging (during stop), the auxiliary power control unit 181 turns on the relays 182 and 185 and turns off the relays 183 and 184 as shown in FIG. Also, it causes the DC / DC converter 186 to execute a boosting operation. As a result, the supply of power from sub battery 187 to loads 20 to 22 is stopped. In addition, the DC / DC converter 186 boosts the power output from the main battery 14 to, for example, about 14 V and supplies it to the sub battery 187. As a result, sub-battery 187 is charged by the power supplied by DC / DC converter 186.

  At this time, the voltage output from the DC / DC converter 186 can be set to a voltage lower than that at the time of door lock release described above. That is, when the door is unlocked, there is a possibility that the engine 12 may be started for a while, so it needs to be charged quickly. However, when the sub battery is charged, the possibility of the engine 12 being started immediately is low. Because it can be charged over time.

  When the charging rate of sub battery 187 becomes equal to or higher than a predetermined threshold (for example, 100%) due to charging, the sub battery charging time is ended and charging of sub battery 187 is completed. The above-mentioned threshold may be set to other than 100%.

  As described above, when the charging rate of the sub battery 187 becomes lower than a predetermined threshold (for example, when the charging rate decreases during long-term parking) while the engine 12 is stopped, the power of the main battery 14 is DC / DC. Since the sub battery 187 is boosted by the converter 186, power can be supplied from the sub battery 187 when the engine 12 is started, and the sub battery 187 can be maintained at a high state of charge. Can extend the service life.

  In addition, since the operation | movement at the time of 2nd sub-battery charge (during driving | running | working) from the lower side of FIG. 5 is the same as that at the time of 2nd sub-battery charge from the lower side of FIG.

  Next, an example of the flow of processing performed in the second embodiment will be described with reference to FIG. In FIG. 6, parts corresponding to those in FIG. 4 are assigned the same reference numerals and descriptions thereof will be omitted. In FIG. 6, steps S10 to S14 are replaced with steps S30 to S33 as compared with FIG. The processes other than this are the same as those in FIG. 4, so the processes in steps S30 to S33 will be mainly described. When the process shown in FIG. 6 is started, the following steps are performed.

  In step S30, the auxiliary power control unit 181 detects the state of the sub battery 187. More specifically, the auxiliary power supply control unit 181 pulse discharges the sub-battery 187, detects changes in voltage and current at that time by the voltage sensor 188 and the current sensor 189, calculates the internal impedance, and calculates the internal impedance. Find the charge rate from

  In step S31, the auxiliary power control unit 181 determines whether charging of the sub battery 187 is necessary based on the charging rate of the sub battery 187 detected in step S30, and determines that charging is necessary (step S31). If yes, the process proceeds to step S32. If not (step S31: No), the process proceeds to step S33.

  In step S32, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the state at the time of sub battery charging. That is, the auxiliary power supply control unit 181 turns on the relays 182 and 183, turns off the relays 184 and 185, and sets the DC / DC converter 186 in an operating state (step-up state: 14 V, for example). As a result, power is not supplied to the loads 21 and 22, and the power output from the main battery 14 is boosted by the DC / DC converter 186 to charge the sub-battery 187. As a method of charging sub battery 187, charging may be performed with a constant current instead of charging with a constant voltage.

  In step S33, the auxiliary power control unit 181 sets the relays 182 to 185 and the DC / DC converter 186 to the normal state. That is, the auxiliary power supply control unit 181 turns on the relays 182 to 184, turns off the relay 185, and sets the DC / DC converter 186 in a stopped state (through state). As a result, the loads 20 to 22 are supplied with power from the main battery 14.

  The operations other than those described above are the same as those in the case of FIG.

  According to the above flow chart, when the charging rate of sub battery 187 falls below a predetermined threshold when engine 12 is stopped, power of main battery 14 is boosted by DC / DC converter 186 and sub battery 187 is charged. Therefore, power can be supplied to the loads 21 and 22 when the engine 12 is started, and the life of the sub battery 187 can be extended.

(D) Description of Modified Embodiments It goes without saying that the above embodiment is an example, and the present invention is not limited only to the case described above. For example, in the example of FIGS. 3 and 5, the relay 183 is turned off at the time of power failure, but may be turned on. In addition, although the power is supplied from the sub battery 187 also to the load 22 when the engine 12 is started, the power may be supplied from the sub battery 187 only to the load 21.

  Further, although the DC / DC converter 186 is stopped (through) at the time of sub-battery charging in FIG. 3 or at the time of sub-battery charging in FIG. 5 (during traveling), the charging operation (boosting operation) may be made.

  Moreover, in the above embodiment, although the case where it has 3 types of loads of load 20-23 was mentioned as an example and demonstrated, it may be 2 types, or may be 4 or more types, for example.

  Further, it is needless to say that the flowcharts shown in FIG. 4 and FIG. 6 are one example, and the present invention is not limited to such processing. For example, when the power is lost, the process proceeds to step S26 to end the process. However, when the power is restored, the process may return to step S10 or the like. Further, when the door lock is released, it is set when the door lock is released according to the charge state of the sub battery 187. However, regardless of the state of the sub battery 187, it may be set each time the door lock is released.

  In the above embodiment, the control unit 10 detects the state of the main battery 14 and the auxiliary power control unit 181 performs the state detection of the sub battery 187. However, one of the main battery 14 and the other is excluded. The states of both batteries may be detected.

  In the case of the sub-battery 187, when the temperature detected by the temperature sensor 190 is out of the predetermined temperature range, either one of the loads 21 and 22 is supplied with power, or neither of the loads is supplied with power. In order to prolong the life, the

  Further, in step S10 of the flowchart shown in FIG. 4, the determination is made based on the release of the door lock. However, for example, the determination may be made based on the door being opened. That is, when the door is opened, it may be determined as Yes and the process may proceed to step S11.

  Further, in the flowchart shown in FIG. 4, when charging of the sub-battery 187 is required, charging is performed regardless of the state of the main battery 14. For example, the charging rate of the main battery 14 is a predetermined threshold value. In the following cases (for example, in the case where the engine 12 can not be started up or less), the charging may not be performed. Similarly, in the flowchart shown in FIG. 6 as well, when the charging rate of the main battery 14 is equal to or less than a predetermined threshold (eg, equal to or less than the threshold that prevents starting of the engine 12), charging is not performed. It is also good.

  Also, in the flowchart shown in FIG. 4, the case where the voltage output from the DC / DC converter 186 is constant has been described as an example, but for example, the voltage or current may be adjusted according to the charging rate. . For example, when the charging rate is low, the voltage output from the DC / DC converter 186 may be set to be high or the current may be set to be increased. According to such a method, when the charging rate is low, charging can be performed rapidly by setting the voltage of the DC / DC converter 186 high or increasing the current.

  Further, in the above embodiment, the state of the main battery 14 is detected by voltage. For example, the state of the main battery 14 is detected by the state of charge (SOC), and a predetermined threshold (for example, If it is less than 80%, it may be determined that the power supply is in a failure state.

DESCRIPTION OF SYMBOLS 10 control part 11 starter motor 12 engine 13 alternator 14 main battery 15,193 voltage sensor 16,194 current sensor 17,195 temperature sensor 18 auxiliary power supply part 20-22 load 181 auxiliary power supply control part (control means)
182 to 185 relay 186 DC / DC converter (boosting means, charging means)
187 sub battery

Claims (7)

In a power supply apparatus mounted on a vehicle and supplying power supply power to a load,
A sub battery provided separately from the main battery mounted on the vehicle and having a smaller electric capacity than the main battery;
Boosting means for boosting power output from the main battery;
Charging means for charging the sub-battery by the power boosted by the boosting means;
Control means for performing control of charging the sub-battery by the charging means while the engine of the vehicle is stopped ;
The control means is the case where the engine of the vehicle is stopped and the door of the vehicle is unlocked or when the door is opened, the engine of the vehicle is simply stopped. Execute control to charge the sub-battery with a higher voltage than when
A power supply device characterized by The control means executes control for charging the sub-battery when the engine of the vehicle is stopped and the charging rate of the sub-battery becomes equal to or less than a predetermined threshold. The power supply device according to claim 1. The boosting means stops the boosting operation after the engine of the vehicle is started,
The charging unit charges the sub-battery with power output from an alternator.
The power supply device according to claim 1 or 2, characterized in that: The power supply apparatus according to any one of claims 1 to 3, wherein the control means does not execute charging of the sub-battery when the charging rate of the main battery is equal to or less than a predetermined value. The power supply device according to any one of claims 1 to 4, wherein the main battery and the sub-battery are both secondary batteries. The power supply device according to any one of claims 1 to 5, wherein the main battery is accommodated in a bonnet in front of the vehicle, and the sub-battery is accommodated at a place other than the bonnet. A power supply device mounted on a vehicle and supplying power source power to a load, the control of the power supply device having a sub-battery which is provided separately from the main battery mounted on the vehicle and has a smaller electric capacity than the main battery In the method
A boosting step of boosting power output from the main battery;
Charging the sub-battery by the power boosted in the boosting step;
A control step of performing control of charging the sub-battery by the charging step while the engine of the vehicle is stopped;
The control step is when the engine of the vehicle is stopped and the door of the vehicle is unlocked or when the door is opened, the engine of the vehicle is simply stopped Execute control to charge the sub-battery with a higher voltage than when
And controlling the power supply device.

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