JP2009005508A - Power accumulator for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power accumulator for a vehicle capable of charging a power accumulating section at high speed. <P>SOLUTION: The power accumulator for the vehicle 11 wherein an output of a main power unit 15 is branched into a constantly-energized system 21 and an ignition switch system 27 via an ignition switch 23 comprises a selective switch 31 connected to the constantly-energized system 21, a charging circuit 35 connected to the ignition switch system 27 and the selective switch 31, a power accumulating section 39 connected between the charging circuit 35 and a load 17, and a control circuit 47 to which the charging circuit 35 and the selective switch 31 are connected, wherein the control circuit 47 charges the power accumulating section 39 with a large current of the constantly-energized system 21 until the ignition switch 23 is turned on after a vehicle pre-start signal is received, and when the ignition switch 23 is turned on, large-current charging is performed from the ignition switch system 27, and at the time of re-charging in the use of a vehicle, large current-charging is also performed from the ignition switch system 27. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular power storage device as an auxiliary power supply that supplies power from a power storage unit when a voltage of a main power supply is lowered.

  2. Description of the Related Art In recent years, automobiles (hereinafter referred to as vehicles) equipped with an idling stop function for stopping engine driving when the vehicle is stopped for environmental considerations and fuel efficiency improvement are on the market. In such a vehicle, when a starter that consumes a large current intermittently during use is driven, the voltage of the battery temporarily drops. As a result, the supply voltage to other loads such as audio and car navigation also decreases, and the operation may become unstable.

  Also, regarding vehicle braking, various vehicle braking systems from conventional mechanical hydraulic control to electrical hydraulic control have been proposed, but when the battery becomes abnormal, the vehicle braking system operates. There was a possibility of disappearing.

  On the other hand, a vehicle power storage device as an auxiliary power source for supplying sufficient power to the load when the voltage of the battery temporarily drops or supplying power to the vehicle braking system when the battery is abnormal is disclosed in, for example, Patent Document 1 below. Has been proposed. Patent Document 1 is shown as a power supply backup unit that supplies electric power to an electronic control unit of a vehicle braking system, particularly when the battery is abnormal, among vehicle power storage devices.

  FIG. 5 is a block circuit diagram of such a vehicle power storage device. For example, a large-capacity electric double layer capacitor is used as a power storage element that stores electric power, and a plurality of these are connected to form a capacitor unit 101 as a power storage unit. The capacitor unit 101 is connected to a charging circuit 103 that controls charging and discharging, and a discharging circuit 105. The charging circuit 103 and the discharging circuit 105 are controlled by the microcomputer 107. The microcomputer 107 is connected to voltage detection means 109 for detecting battery abnormality, and the voltage detection means 109 is connected to an FET switch 111 that supplies electric power to the capacitor unit 101 when abnormality occurs.

  The vehicle power storage device 113 as the power backup unit configured as described above is connected between the battery 115 and the electronic control unit 117, and is controlled to be started and stopped by the ignition switch 119.

  Next, the operation of such a vehicle power storage device will be described.

  Since the electronic control unit 117 is a vehicle braking system, the electronic control unit 117 must be continuously driven even when the battery 115 becomes abnormal in order to ensure safety. Therefore, if the voltage detection means 109 detects an abnormality of the battery 115, the FET switch 111 is turned on to supply the electric power of the capacitor unit 101 to the electronic control unit 117, thereby responding to the abnormality of the battery 115. Further, at the end of use of the vehicle, the electric power stored in the capacitor unit 101 is discharged by the discharge circuit 105 in order to extend the life of the capacitor unit 101.

Such a power storage device for a vehicle may be applied not only to the electronic control unit 117 of the vehicle braking system but also to audio and car navigation for an idling stop vehicle as a load. In this case, the operation of the load can be continued by supplying the power of the capacitor unit 101 to the load when the voltage of the main power source (battery 115) is temporarily lowered due to starter driving after idling is stopped.
JP 2005-28908 A

  According to the above vehicle power storage device, it is possible to continue to drive the electronic control unit 117 when the battery 115 is abnormal, or to continue driving a load such as audio when the battery 115 temporarily drops. For this purpose, the capacitor unit 101 needs to be fully charged in advance. However, as described above, since the electric power of the capacitor unit 101 is discharged at the end of use of the vehicle, it takes time to fully charge the capacitor unit 101 especially at the time of starting the vehicle. The power cannot be supplied.

  Therefore, in order to shorten the charging time of the capacitor unit 101, it is sufficient to simply increase the charging current. In this case, in the configuration of FIG. 5, the charging circuit 103 for charging the capacitor unit 101 is in a state of being directly connected to the battery 115, but in an actual vehicle, fuses are arranged in both wiring systems ( The fuse is omitted in FIG. 5). Since this fuse is also connected to another large current consumption load mounted on the vehicle, when the capacitor unit 101 is charged at the time of starting the vehicle, the driving current of the large current consumption load also flows through the fuse. For this reason, when the charging current of the capacitor unit 101 is increased, the allowable current capacity of the fuse is approached, and the fuse may be blown depending on the use state of the large current consumption load. Therefore, for example, in the configuration of FIG. 5, the capacitor unit 101 is charged in a current range not exceeding 70% of the allowable current capacity. Therefore, the charging current cannot be increased, and there is a problem that it takes time to charge the capacitor unit 101 when the vehicle is started.

  An object of the present invention is to solve the above-described conventional problems and to provide a vehicle power storage device that can charge a capacitor unit 101 at high speed.

  In order to solve the above-described conventional problems, the power storage device for a vehicle according to the present invention is connected between a main power source and a load, and is stored in advance when the voltage (Vb) of the main power source is equal to or lower than a predetermined lower limit value. A power storage device for a vehicle that supplies electric power to the load, wherein the output of the main power source is branched into a constantly energized system through a first fuse and an ignition switch system through a series circuit of an ignition switch and a second fuse. The vehicle power storage device is connected between the selection switch connected to the constantly energized system, the ignition switch system, a charging circuit connected to the selection switch, and between the charging circuit and the load. A power storage unit; and a control circuit to which the charging circuit and the selection switch are connected. The control circuit turns on the selection switch when receiving a signal before starting the vehicle. Then, the electric power of the main power source from the always energized system is charged to the power storage unit by the charging circuit, and when the ignition switch is turned on, the selection switch is turned off and the power from the ignition switch system is turned off. The electric power of the main power source is charged into the power storage unit by the charging circuit.

  According to the vehicle power storage device of the present invention, there is a margin to the allowable current capacity of the fuse while the large current consumption load from when the signal before starting the vehicle is received until the ignition switch is turned on is not used. When the storage unit is charged with a large current from the always energized system and the ignition switch is turned on, the storage unit is continuously charged with a large current from the ignition switch system that originally has a margin up to the allowable current capacity of the fuse, and while the vehicle is in use Even in recharging after the power is consumed, large current charging can be performed from the ignition switch system, so that the power storage unit can be charged at high speed.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1 is a block circuit diagram of a power storage device for a vehicle in an embodiment of the present invention. FIG. 2 is a flowchart at the time of starting the power storage device for a vehicle in the embodiment of the present invention. FIG. 3 is a flowchart when the main power supply voltage of the vehicular power storage device according to the embodiment of the present invention decreases. FIG. 4 is a flowchart at the end of use of the vehicle power storage device in the embodiment of the present invention. In FIG. 1, thick lines indicate power system wirings, and thin lines indicate signal system wirings. In this embodiment, the case where the power storage device for a vehicle is applied to an idling stop vehicle will be described.

  In FIG. 1, the vehicle power storage device 11 is connected between a main power supply 15 and a load 17. The main power supply 15 is a battery, and a starter (not shown) that consumes a large current intermittently is also connected. The load 17 is an auxiliary device such as audio and navigation.

  The output of the main power supply 15 is branched into a constantly energizing system 21 via a first fuse 19 and an ignition switch system 27 via a series circuit of an ignition switch 23 and a second fuse 25 of the vehicle. The constantly energized system 21 is a system that supplies electric power for driving a large current consumption load (not shown) in the vehicle (for example, a motor such as a window and a wiper, and an illumination such as a headlight), and the ignition switch system 27 is a load 17 ( Auxiliary machinery) and a system for supplying electric power to the control circuit (not shown) of the large current consumption load. Therefore, a large current always flows through the energization system 21 when the vehicle is started or used, but a very large current does not flow through the ignition switch system 27. Therefore, the second fuse 25 has a margin up to the allowable current capacity.

  Next, the configuration of the vehicle power storage device 11 will be described. First, one end of a selection switch 31 formed of an FET is connected to the constant current supply system 21 via a first diode 29, and a main power supply voltage detection circuit 33 that detects the voltage Vb of the main power supply 15 is connected. The main power supply voltage detection circuit 33 has a function of detecting the voltage of the power system wiring (thick line) and outputting it to the outside.

  A charging circuit 35 is connected to the other end of the ignition switch system 27 and the selection switch 31. A second diode 37 is connected between the ignition switch system 27 and the charging circuit 35. The first diode 29 and the second diode 37 mutually prevent the backflow of electric power from the always energized system 21 and the ignition switch system 27. In addition, the charging circuit 35 has a function of charging to a set voltage with a constant current or a constant voltage while detecting a voltage Vc of a power storage unit described later. Further, it has a function of outputting the detected voltage Vc.

  A power storage unit 39 is connected between the output of the charging circuit 35 and the load 17. The power storage unit 39 is configured to supply necessary power by connecting a plurality of electric double layer capacitors (six in this embodiment) in series as power storage elements, for example. Here, since the rated voltage of the electric double layer capacitor is 2.2 V, the full charge voltage of the power storage unit 39 is 13.2 V (= 2.2 V × 6). Depending on the required power specifications of the load 17, the number of electric double layer capacitors may be increased or decreased, or a series-parallel connection may be used.

  A changeover switch 41 and a third diode 43 are further connected in series between the power storage unit 39 and the load 17. The change-over switch 41 has a configuration that can be controlled on and off from the outside. Here, as with the selection switch 31, an FET is used. The third diode 43 has an anode connected to the changeover switch 41 and a cathode connected to the load 17.

  Note that the fourth diode 45 is connected between the first fuse 19 and the load 17 also in the vehicle-side constantly energized system 21. The fourth diode 45 has an anode connected to the first fuse 19 and a cathode connected to the load 17. Therefore, the third diode 43 and the fourth diode 45 prevent the power from the main power supply 15 and the power from the power storage unit 39 from flowing back to each other.

  The charging circuit 35, the main power supply voltage detection circuit 33, the selection switch 31, and the changeover switch 41 are also connected to the control circuit 47 through signal lines. The control circuit 47 includes a microcomputer and peripheral circuits, and controls the overall operation of the vehicle power storage device 11. That is, the control circuit 47 reads the voltage Vc of the power storage unit 39 from the output of the charging circuit 35 and reads the voltage Vb of the main power supply 15 from the output of the main power supply voltage detection circuit 33. In addition, the control circuit 47 controls the charging circuit 35 by transmitting a charging control signal Ccont to the charging circuit 35, and performs on / off control of the selection switch 31 by transmitting a selection switch on / off signal SF to the selection switch 31. By transmitting a changeover switch on / off signal Sof to the changeover switch 41, the on / off control of the changeover switch 41 is performed. The control circuit 47 has a function of communicating with a vehicle-side control circuit (not shown) by transmitting and receiving data signals data.

  Next, with respect to the operation of the vehicle power storage device 11, the operation at the time of starting will be described with reference to the flowchart of FIG. 2. Since the control circuit 47 has a software configuration for performing the entire operation by executing various subroutines as necessary from the main routine, the flowchart shown in FIG. 2 is shown in the form of a subroutine. In the same manner, all flowcharts are shown in the form of subroutines.

  Before the vehicle is started (when the vehicle is not used), the control circuit 47 is in a standby state called a sleep mode. Thereby, the start-up time of the vehicle power storage device 11 can be advanced as compared with the case where the control circuit 47 is completely turned off.

  In this state, when the driver performs an unlocking operation or opens the door to use the vehicle, an unlocking signal or an opening signal (hereinafter collectively referred to as a pre-vehicle activation signal) is sent to the vehicle-side control circuit. To the control circuit 47 as a data signal data. As a result, the control circuit 47 starts immediately and executes the main routine. Since the main routine is currently activated, the activation subroutine shown in FIG. 2 is executed. The door opening signal or the unlocking signal is transmitted as a data signal data to the control circuit 47 when at least one of the signals is obtained. As a result, the earlier signal before starting the vehicle is transmitted to the control circuit 47, so that high-speed starting is possible. Further, as the unlocking signal, a signal transmitted from the key to the vehicle by wireless means may be used as it is. As a result, the control circuit 47 is activated in a state in which the driver approaches the vehicle, so that even higher speed activation is possible.

  When the subroutine of FIG. 2 is executed, the control circuit 47 transmits a selection switch on / off signal SF to the selection switch 31 to turn on the selection switch 31 (step number S11). In response to this, the selection switch 31 is turned on. This is because the ignition switch 23 is still in an off state at the time of S11, so that the selection switch 31 is turned on in order to secure a power system for charging the power storage unit 39 with the power of the main power supply 15.

  Next, the control circuit 47 reads the voltage Vc of the power storage unit 39 by the charging circuit 35 (S13), and compares the voltage Vc with the set voltage (S15). Here, the set voltage is the full charge voltage (= 13.2 V) of the power storage unit 39. If the voltage Vc is lower than the set voltage (Yes in S15), it is assumed that the power storage unit 39 has caused self-discharge or the like when the vehicle is not used. Is charged (S17). Thereafter, it is determined whether or not the ignition switch 23 is turned on (S19). The on / off state of the ignition switch 23 is transmitted from the vehicle side control circuit to the control circuit 47 by the data signal data. If the ignition switch 23 is off (No in S19), the process returns to S13, and the operation of charging until the set voltage is reached is repeated.

  On the other hand, if the ignition switch 23 is turned on (Yes in S19), the selection switch 31 is turned off (S21). By operating in this way, an inrush current to the power storage unit 39 is avoided. That is, if the selection switch 31 is turned off before the ignition switch 23 is turned on, an inrush current flows from the ignition switch system 27 to the power storage unit 39 at the moment when the ignition switch 23 is turned on. There is a possibility of affecting the parts and wiring system. Therefore, in the present embodiment, control is performed such that the selection switch 31 is turned off after the ignition switch 23 is turned on to obtain high reliability.

  After S21, the process returns to S13, and the operation of charging until the set voltage is reached is repeated.

  The operations from S11 to S21 described above are the operations that characterize the present embodiment. That is, as soon as the control circuit 47 receives the signal before starting the vehicle, the control circuit 47 switches from the standby state to the start state, turns on the selection switch 31 and charges the power storage unit 39 with the power from the main power supply 15 from the always energized system 21 by the charging circuit 35. When the ignition switch 23 is turned on, the selection switch 31 is turned off, and the electric power of the main power supply 15 from the ignition switch system 27 is charged into the power storage unit 39 by the charging circuit 35. By such an operation, the power storage unit 39 can be charged at high speed when the vehicle is started. The reason is as follows.

  Since the vehicle is still not in use until the ignition switch 23 is turned on after receiving the signal before starting the vehicle, the large current consumption load connected to the energization system 21 is not always driven. Therefore, the current flowing through the first fuse 19 is small, and there is a sufficient margin up to the allowable current capacity. Therefore, the power storage unit 39 can be charged with a large current from the always energized system 21. Thereafter, when the ignition switch 23 is turned on, the large current consumption load starts to be driven. As a result, there is a possibility that the allowable current capacity of the first fuse 19 may be exceeded if the charging current to the power storage unit 39 is kept flowing as it is when the ignition switch 23 is off. Therefore, when the ignition switch 23 is turned on, the power storage unit 39 is continuously charged with a large current from the ignition switch system 27 that originally has a large allowable current capacity of the second fuse 25. Therefore, since a large current can be always charged from the reception of the signal before starting the vehicle until the charging of the power storage unit 39 is completed, the power storage unit 39 can be charged at a high speed when the vehicle is started.

  In addition, although the structure which charges the electrical storage part 39 only by the ignition switch system 27 from the beginning at the time of starting is also considered, although a large current charge is possible, the electrical storage part 39 can be charged until the ignition switch 23 turns on. It cannot be done and it takes time to complete charging. Therefore, it is necessary to have the above configuration and operation.

  Here, returning to S15, if the voltage Vc of the power storage unit 39 is equal to or higher than the set voltage (No in S15), the control circuit 47 turns off the selection switch 31 (S23). This operation is the same as S21, but the reason for performing the operation of turning off the selection switch 31 again is as follows.

  The control circuit 47 controls the power storage unit 39 to be charged with the electric power of the power supply system 21 until the ignition switch 23 is turned on after receiving the signal before starting the vehicle. If it takes a long time to turn on the ignition switch 23 after opening the door, there is a possibility that the full charge of the power storage unit 39 may be completed with the electric power of the constantly energized system 21. In this case, since the operation of S21 is not performed, the selection switch 31 remains on in S11. If left in this state, power is supplied to the power storage unit 39 from both the constant charging system 21 and the ignition switch system 27 at the time of recharging after supplying the power of the power storage unit 39 to the load 17 after idling is stopped. As a result, there is no problem because the second fuse 25 has a margin for the allowable current capacity as described above, but the first fuse 19 is charged with the power storage unit 39 when a plurality of large current consumption loads are operating simultaneously, for example. May increase the current and exceed the allowable current capacity. Therefore, in the present embodiment, the power storage unit 39 is always charged from the ignition switch system 27 while the vehicle is in use. Thereby, even when recharging, the power storage unit 39 can be charged at high speed regardless of the operating state of the large current consumption load.

  From the above, the selection switch 31 is always turned off when the vehicle is used by turning off the selection switch 31 in S23 regardless of the on / off state of the selection switch 31.

  After S23, the control circuit 47 controls the charging circuit 35 so as to maintain the set voltage of the power storage unit 39 (S25). Thereby, since the start of the power storage device 11 for the vehicle is completed, the subroutine of FIG. 2 is terminated and the process returns to the main routine.

  Next, the operation when the voltage Vb of the main power supply 15 is reduced by the starter operation after idling stop during use of the vehicle will be described with reference to the flowchart of FIG. The main routine of the control circuit 47 executes the subroutine of FIG. 3 as appropriate when the vehicle is used (for example, every predetermined time).

  Thereby, first, the control circuit 47 reads the voltage Vb of the main power supply 15 from the main power supply voltage detection circuit 33 (S31). Next, the voltage Vb is compared with a predetermined lower limit value (S33). Here, the predetermined lower limit value is the lowest voltage (10.5 V in the present embodiment) for operating the load 17. If the voltage Vb is larger than the predetermined lower limit value (No in S33), the vehicle is in a normal driving state and the main power supply 15 outputs a normal voltage, so the subroutine of FIG. Return to the main routine.

  On the other hand, if the voltage Vb is equal to or lower than the predetermined lower limit value (Yes in S33), the idling stop is completed and the main power supply 15 is driving the starter. Will be waking up. In this case, the control circuit 47 turns on the changeover switch 41 (S35). Specifically, the changeover switch on / off signal Sof is transmitted from the control circuit 47 to the changeover switch 41 as an on signal. Thereby, the electric power of the electrical storage unit 39 flows in the direction of the arrow written as the discharge path in FIG. 1 and is supplied to the load 17. At this time, since the anode voltage of the fourth diode 45 (= the voltage of the main power supply 15) is smaller than the cathode voltage (= the voltage applied to the load 17 by the power storage unit 39), the fourth diode 45 is turned off and stored. The power of the unit 39 is not supplied to the main power supply 15. For this reason, the electric power of the power storage unit 39 is supplied only to the load 17 and the load 17 continues to operate.

  Next, the control circuit 47 reads the voltage Vb of the main power supply 15 and the voltage Vc of the power storage unit 39 (S37). After that, the voltage Vb is first compared with the predetermined lower limit value (S39). If the voltage Vb remains below the predetermined lower limit value (No in S39), it is assumed that the starter is being driven. Vc is compared with a predetermined lower limit (10.5 V as in S39) (S41). If the voltage Vc is greater than the predetermined lower limit (No in S41), a normal voltage is being applied from the power storage unit 39 to the load 17, so that the power storage unit 39 continues to supply power to the load 17. Returning to S37, the voltage Vb and the voltage Vc are continuously monitored.

  On the other hand, if the voltage Vc is equal to or lower than the predetermined lower limit (Yes in S41), the voltage Vb of the main power supply 15 is equal to or lower than the predetermined lower limit and the voltage Vc is equal to or lower than the predetermined lower limit. Can't keep driving. In this case, since the power of the power storage unit 39 is used without the voltage Vb recovering due to some abnormality such as the main power supply 15 or the starter, the control circuit 47 sends a main power supply abnormality signal to the vehicle side control circuit. Output (S43). In response, the vehicle-side control circuit warns the driver of an abnormality in the power system of the main power supply 15 and prompts repair. Thereafter, the subroutine of FIG. 3 is terminated.

  Here, returning to S39, when the starter driving is completed and the voltage Vb returns to a voltage higher than the predetermined lower limit (Yes in S39), the load 17 can be operated again with the power of the main power supply 15, so switching The switch 41 is turned off (S45). As a result, the power supply from the power storage unit 39 is stopped, so that the cathode side voltage of the third diode 43 decreases, but the voltage Vb of the main power supply 15 has recovered to a predetermined lower limit value or more, so the fourth diode 45 Becomes higher than the cathode voltage, and the fourth diode 45 is turned on. As a result, the power of the main power supply 15 is supplied to the load 17 again.

  Next, in order to prepare for the next idling stop, the control circuit 47 charges the power discharged from the power storage unit 39 to the load 17 from the main power supply 15 again. Specifically, first, the voltage Vc of the power storage unit 39 is read from the charging circuit 35 (S37), and the voltage Vc is compared with the set voltage (= 13.2 V) (S49). If the voltage Vc is smaller than the set voltage (Yes in S49), since the power storage unit 39 is not fully charged, the power of the main power supply 15 is charged to the power storage unit 39 by the charging circuit 35 (S51). At this time, since the selection switch 31 is off as described above, the electric power of the ignition switch system 27 is charged in the power storage unit 39. Then, it returns to S47 and repeats the operation | movement charged until it reaches a setting voltage.

  On the other hand, if the voltage Vc is equal to or higher than the set voltage (No in S49), the control circuit 47 controls the charging circuit 35 so as to maintain the set voltage of the power storage unit 39 (S53). Thereafter, the subroutine of FIG. 3 is terminated and the process returns to the main routine.

  As described above, when the power storage unit 39 is recharged during use of the vehicle, charging is performed from the electric power of the ignition switch system 27. Therefore, high-speed charging can be performed without being influenced by the driving state of the large current consumption load. It is possible to respond quickly to idling stops.

  Next, the operation of the vehicle power storage device 11 when the use of the vehicle is terminated will be described with reference to FIG. When the use of the vehicle is finished and the ignition switch 23 is turned off by the driver, the control circuit 47 executes the subroutine of FIG. Thereby, the control circuit 47 transmits the charge control signal Ccont to the charging circuit 35 so as to stop the operation (S61). As a result, the charging circuit 35 operates to maintain the voltage Vc of the power storage unit 39, but stops this. Thereafter, the subroutine of FIG. 4 is terminated, the process returns to the main routine, and the control circuit 47 is set in a standby state. As a result, the vehicle power storage device 11 can be started quickly when the next vehicle is used, and the power consumption when the vehicle is not used is reduced.

  With the above-described configuration and operation, the power storage unit 39 is charged with a large current from the energized system 27 constantly until the ignition switch 23 is turned on after receiving the signal before starting the vehicle, and the ignition switch 23 is turned on when the ignition switch 23 is turned on. The charging is continued from the switch system 27 with a large current, and the large charge can be charged from the ignition switch system 27 even in the recharging after the power of the power storage unit 39 is consumed during use of the vehicle. It is possible to realize a vehicular power storage device that can be used.

  In the present embodiment, the power of power storage unit 39 is not actively discharged at the end of vehicle use. As a result, although the stored power is reduced due to the self-discharge of the power storage unit 39 at the next vehicle start-up, a certain amount of power is stored in advance, so that high-speed start is possible. However, if the power is stored in the power storage unit 39, the electric double layer capacitor constituting the power storage unit 39 may deteriorate due to environmental conditions and the like, and the life may be shortened. Therefore, a discharge circuit connected to the control circuit 47 may be provided between the power storage unit 39 and the load 17 as in the prior art so that the control circuit 47 discharges the power storage unit 39 by the discharge circuit when the vehicle is finished using. . Thereby, deterioration of the electrical storage part 39 can be reduced. In addition, although the time for fully charging the power storage unit 39 at the time of start-up is slower than when the discharge circuit is not used, it is not necessary to suppress the charging current as in the prior art, so the power storage unit 39 is faster than the conventional configuration. Can be fully charged. Therefore, whether or not to use the discharge circuit may be appropriately determined in consideration of the environmental conditions of the vehicle power storage device 11 and the required charging time.

  Further, in the present embodiment, when both the voltage Vb of the main power supply 15 and the voltage Vc of the power storage unit 39 are equal to or lower than the predetermined lower limit value, an abnormality signal of the main power supply 15 is output to the vehicle-side control circuit ( In S43) of FIG. 3, in the case where the vehicle side control circuit detects the voltage Vb of the main power source 15, the abnormality of the main power source 15 is known, so the operation of S43 is not particularly required. In this case, the control circuit 47 only needs to receive the signal before starting the vehicle from the vehicle-side control circuit, and the transmission function to the vehicle-side control circuit becomes unnecessary, so that the cost of the control circuit 47 can be reduced.

  Further, in the present embodiment, the electric double layer capacitor is used as the electric storage element in the electric storage unit 39, but this may be another electric storage element such as an electrochemical capacitor.

  Moreover, although the case where the vehicle power storage device 11 is applied to an idling stop vehicle has been described, the present invention is not limited thereto, and it is used as an auxiliary power source in each system such as a hybrid vehicle, a vehicle braking system, an electric power steering, and an electric supercharger. Is also applicable.

  Since the power storage device for a vehicle according to the present invention can charge the power storage unit at high speed, it is particularly useful as a power storage device for a vehicle as an auxiliary power source that supplies power from the power storage unit when the voltage of the main power supply is lowered.

The block circuit diagram of the electrical storage apparatus for vehicles in embodiment of this invention Flowchart at startup of power storage device for vehicle in the embodiment of the present invention The flowchart at the time of the main power supply voltage fall of the electrical storage apparatus for vehicles in embodiment of this invention Flowchart at the end of use of the vehicle power storage device in the embodiment of the present invention Block circuit diagram of a conventional vehicle power storage device

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Vehicle power storage device 15 Main power supply 17 Load 19 First fuse 21 Always energized system 23 Ignition switch 25 Second fuse 27 Ignition switch system 31 Selection switch 35 Charging circuit 39 Power storage unit 47 Control circuit

Claims (5)

A power storage device for a vehicle that is connected between a main power source and a load, and that supplies power stored in advance to the load when a voltage (Vb) of the main power source is equal to or lower than a predetermined lower limit value,
The output of the main power supply is branched into a constantly energized system via the first fuse and an ignition switch system via a series circuit of the ignition switch and the second fuse,
The vehicle power storage device includes a selection switch connected to the constantly energized system,
A charging circuit connected to the ignition switch system and the selection switch;
A power storage unit connected between the charging circuit and the load;
The charging circuit and a control circuit connected to the selection switch,
The control circuit turns on the selection switch when receiving a signal before starting the vehicle, and charges the power storage unit with the electric power of the main power source from the constantly energized system by the charging circuit,
When the ignition switch is turned on, the power storage device for a vehicle is configured such that when the ignition switch is turned on, the selection switch is turned off, and the power storage unit is charged by the charging circuit with the power of the main power source from the ignition switch system. The vehicle power storage device according to claim 1, wherein the vehicle start signal is at least one of an opening signal and an unlocking signal. The vehicle power storage device according to claim 1, wherein the selection switch is always turned off when the vehicle is used. Between the power storage unit and the load, a discharge circuit connected to the control circuit is provided,
The power storage device for a vehicle according to claim 1, wherein the control circuit discharges the power storage unit by the discharge circuit when use of the vehicle ends. The power storage device for a vehicle according to claim 1, wherein the control circuit is in a standby state when the vehicle is not used.

Images