JP5266892B2 - Power storage device - Google Patents

Description

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

  A power supply device including a power storage device as an auxiliary power source for supplying sufficient electric power to a load when a temporary battery voltage drop occurs at the time of starting an engine of an automobile (hereinafter referred to as a vehicle) is disclosed in, for example, Patent Literature 1 is proposed. FIG. 3 is a block circuit diagram of such a power supply device. The power storage device 101 is first provided with an auxiliary power supply unit 103 composed of an electric double layer capacitor for storing power. A charging circuit 105 is connected to the auxiliary power supply unit 103. In addition, a stabilization circuit 107 that outputs power of the auxiliary power supply unit 103 is also connected. A detection circuit 109 for detecting the voltage is connected to the input side of the charging circuit 105. In addition, a power supply switching unit 111 that switches between supplying power from the auxiliary power supply unit 103 or the main power supply unit 115 according to the detection voltage of the detection circuit 109 is connected. The power supply switching unit 111 has a configuration for switching contact of terminals, and for example, a relay is used.

  The main power source 115 made of a battery is connected to the input side of the power storage device 101, that is, the input of the charging circuit 105, via a first switch 113. One end of a second switch 117 is connected between the first switch 113 and the power storage device 101, and the other end is connected to a starter (not shown) built in the engine 119. The first switch 113 and the second switch 117 are on / off controlled by a key mounting part 121. The key mounting unit 121 has four modes: a lock mode, an accessory mode, an on mode, and a start mode. In the lock mode, both the first switch 113 and the second switch 117 are turned off. In the accessory mode and the on mode, the first switch 113 is turned on, and the second switch 117 is turned off. In the start mode, both the first switch 113 and the second switch 117 are turned on. In addition, an in-vehicle device 123 such as an audio or car navigation system is connected to the output side of the power storage device 101, that is, the output of the power supply switching unit 111.

  Next, the operation of the power storage device 101 will be described. First, when a key is inserted into the key mounting part 121 when the vehicle is started and the accessory mode is set, the first switch 113 is turned on. As a result, the power of the main power supply unit 115 is supplied to the charging circuit 105, the detection circuit 109, and the power supply switching unit 111. Thereby, the charging circuit 105 charges the auxiliary power supply unit 103 and the power supply switching unit 111 selects the main power supply unit 115 side as shown in FIG. Power from the power supply unit 115 is supplied, and audio, car navigation, and the like operate.

  In this state, when the key of the key mounting portion 121 is set to the start mode in order to start the engine, the second switch 117 is also turned on. As a result, the electric power of the main power supply unit 115 is supplied to the starter built in the engine 119, so that the engine 119 is started. At this time, since a large current flows through the starter, the voltage of the main power supply unit 115 greatly decreases accordingly. When the detection circuit 109 detects this change and detects that the change is lower than a predetermined reference value, the power supply switching unit 111 is switched to the auxiliary power supply unit 103 side. Thereby, during operation of the starter, electric power is supplied from the auxiliary power supply unit 103 to the in-vehicle device 123, so that the in-vehicle device 123 can continue to operate.

  Thereafter, the start of the engine 119 is completed, and the second switch 117 is turned off by setting the key to the on mode. As a result, the voltage of the main power supply unit 115 becomes higher than the predetermined reference value. Therefore, the detection circuit 109 detects this change and switches the power supply switching unit 111 to the main power supply unit 115 side. As a result, power is supplied to the in-vehicle device 123 from the main power supply unit 115.

  With such an operation, stable power is continuously supplied to the in-vehicle device 123 even during the operation of the starter, so that interruption of music, deletion of settings, and the like can be avoided.

  FIG. 4 shows a block circuit diagram of a power storage device according to another configuration. The difference from the configuration in FIG. 3 is that the first diode 131 and the second diode 133 are used in place of the power supply switching unit 111. That is, the anode of the first diode 131 is connected to the input side of the charging circuit 105, the cathode is connected to the in-vehicle device 123 side, and the anode of the second diode 133 is connected to the output of the stabilization circuit 107. The cathode is connected to the in-vehicle device 123 side. Further, the detection circuit 109 is eliminated.

  With such a configuration, when the voltage of the main power supply unit 115 is sufficiently high, the first diode 131 is turned on, power is supplied from the main power supply unit 115 to the in-vehicle device 123, and the starter is in operation. When the voltage of the main power supply unit 115 decreases, the second diode 133 is turned on, and the power of the auxiliary power supply unit 103 is supplied to the in-vehicle device 123. Accordingly, the first diode 131 and the second diode 133 are automatically switched on and off according to the voltage fluctuation of the main power supply unit 115.

Even with the configuration and operation as described above, stable power is supplied to the in-vehicle device 123 including when the starter is operating.
JP 2002-64946 A

  According to the above power storage device, it is possible to supply stable power to the load such as the in-vehicle device 123 even if the voltage of the main power supply unit 115 is lowered, but the respective configurations shown in FIGS. 3 and 4 However, there were the following problems.

  First, in the power storage device 101 configured as shown in FIG. 3, when a relay for switching contact between the terminals is used as the power supply switching unit 111, the terminal between the reception of the switching signal from the detection circuit 109 and the actual switching is received. Chattering may occur repeatedly when the contact state is repeatedly turned on and off. This is because the contact of the terminal is mechanically switched by the magnetic force generated from the coil built in the relay. As a result, when the power supply switching unit 111 is switched, there is a problem that power supplied to the in-vehicle device 123 is interrupted or the voltage becomes unstable.

  On the other hand, in the power storage device 101 having the configuration shown in FIG. 4, since the power supply source is switched by the first diode 131 and the second diode 133, the chattering does not occur. However, since the power to the in-vehicle device 123 is always supplied via the first diode 131 or the second diode 133, heat is generated due to the loss of these diodes. In particular, since power is supplied to the in-vehicle device 123 via the first diode 131 during normal vehicle use, the first diode 131 generates more heat than the second diode 133, and its life is short. There was a problem that it might become. Note that the power storage device 101 having the configuration of FIG. 3 does not use a diode, and thus no heat is generated.

  From the above, there is a problem that the voltage may become unstable if the relay is used for the power supply switching unit 111, and heat may be generated if the diode is used.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a power storage device capable of achieving both stabilization of voltage to a load and reduction of heat generation.

In order to solve the conventional problems, a power storage device according to the present invention includes a power storage unit, a main power terminal electrically connected to a main power source, a load terminal electrically connected to a load, and the main power source. A relay that is electrically connected between the terminal and the load terminal , receives a switching signal, and normally closes when the switching signal is off, and is electrically connected between the load terminal and the power storage unit An electronic switch, and a relay and a control circuit electrically connected to the electronic switch , wherein the electronic switch is configured by a series circuit of a first switch and a second switch made of a field effect transistor, The first switch is electrically connected so that the cathode of the first parasitic diode is on the power storage unit side, and the cathode of the second parasitic diode on the second switch is on the load terminal side. When the switching signal is turned on, the control circuit turns on the first switch and turns off the second switch before performing the operation of switching so that the relay is opened, and the relay generates chattering. Is configured such that the first switch is turned on and the second switch is turned off, and the first switch and the second switch are turned on after the relay is opened .

  According to the power storage device of the present invention, the electronic switch is provided between the load terminal and the power storage unit, and the electronic switch is turned on at least during the period when the relay is switched. Therefore, the power of the power storage unit is supplied from the load terminal to the load. The voltage to the load can be stabilized. Furthermore, since the power of the main power supply is normally supplied to the load via the relay, heat generation can be reduced without going through a heating element such as a diode. Therefore, an effect of realizing a power storage device capable of achieving both stabilization of voltage to the load and reduction of heat generation can be obtained.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Here, in an idling stop vehicle, an example will be described in which the power storage device is applied as an auxiliary power source for stably supplying power to the load when the voltage of the battery is temporarily reduced when the engine is started after the idling stop.

(Embodiment)
FIG. 1 is a block circuit diagram of a power storage device according to an embodiment of the present invention. 2A and 2B are a voltage aging diagram and a timing chart of the power storage device according to the embodiment of the present invention, in which FIG. 2A is a chronological change diagram of the voltage Vb of the main power supply terminal and the voltage Vo of the load terminal, (C) is a timing chart of the relay, (d) is a timing chart of the second switch, and (e) is a timing chart of the first switch. In FIG. 1, thick lines indicate power system wirings, and thin lines indicate signal system wirings.

  In FIG. 1, the power storage device 11 is electrically connected between a vehicle main power supply 13 and a load 15. Specifically, the main power supply 13 is electrically connected to the main power supply terminal 17 of the power storage device 11, and the load 15 is electrically connected to the load terminal 19. The main power source 13 is a vehicle battery, and the load 15 is an electrical component such as audio or car navigation. A fuse 21 is electrically connected between the main power supply 13 and the main power supply terminal 17.

  The power storage device 11 has the following configuration. A relay 23 is electrically connected between the main power supply terminal 17 and the load terminal 19. Here, the relay 23 has a normally closed terminal 25, a normally open terminal 27, and a common terminal 29, and electromagnetic switching of the electrical connection between the normally closed terminal 25 and the normally open terminal 27 with respect to the common terminal 29 is performed. The coil 31 for performing it automatically is incorporated. The relay 23 also has a switching terminal 33 for controlling on / off of the coil 31. Here, the normally closed terminal 25 is a terminal that is electrically connected to the common terminal 29 when the coil 31 is not energized, and the normally open terminal 27. Is defined as a terminal that is electrically connected to the common terminal 29 when the coil 31 is energized. Therefore, for example, in FIG. 1, since the normally closed terminal 25 and the common terminal 29 are electrically connected, the coil 31 is in an OFF state.

  In the present embodiment, the specific electrical connection of the relay 23 is as follows. First, the main power terminal 17 is connected to the normally closed terminal 25, and the common terminal 29 is connected to the load terminal 19. Note that nothing is connected to the normally open terminal 27. One end of the coil 31 is electrically connected to the main power supply terminal 17, and the switching terminal 33, which is the other end of the coil 31, is electrically connected to a relay control terminal 35 provided in the power storage device 11. ing.

  One end of an electronic switch 37 is electrically connected to the load terminal 19. The electronic switch 37 is constituted by a series circuit of a first switch 39 and a second switch 41 made of a field effect transistor (hereinafter referred to as FET). Since the first switch 39 and the second switch 41 are FETs, a first parasitic diode 43 and a second parasitic diode 45 are formed respectively. Here, the first parasitic diode 43 of the first switch 39 is electrically connected so that the cathode is on the power storage unit side described later. On the other hand, the second parasitic diode 45 of the second switch 41 is electrically connected so that the cathode is on the load terminal 19 side. In FIG. 1, the second switch 41 and the first switch 39 are electrically connected in this order from the load terminal 19 side. This is the direction of the first parasitic diode 43 and the second parasitic diode 45. If they are not changed, they may be connected in the reverse order.

  Although not shown in FIG. 1, a circuit for stabilizing the voltage Vo may be connected to the load terminal 19.

  The power storage unit 47 is electrically connected to the other end of the electronic switch 37. Therefore, the load terminal 19 and the power storage unit 47 are electrically connected via the electronic switch 37. The power storage unit 47 is composed of a plurality of electric double layer capacitors, and serves as a power source for stably supplying power to the load 15 when the voltage of the main power supply 13 is temporarily reduced when the engine is started.

  A charging circuit 49 for charging the power storage unit 47 is electrically connected between the main power supply terminal 17 and the power storage unit 47. Further, a voltage detection circuit 51 for detecting the voltage Vc is electrically connected to the power storage unit 47.

  A control circuit 53 is electrically connected to the switching terminal 33, the first switch 39, the second switch 41, the charging circuit 49, and the voltage detection circuit 51 through signal system wiring. Therefore, the control circuit 53 takes in the switching signal SL at the switching terminal 33 and the voltage Vc of the power storage unit 47, and also controls the charging circuit 49, the first switch on / off signal SW1, and the second switch. The on / off signal SW2 is output.

  A vehicle control circuit 55 is electrically connected to the relay control terminal 35. The vehicle-side control circuit 55 is a circuit that controls the entire vehicle, and a transistor 57 that controls the coil 31 of the relay 23 is provided in a part thereof. The relay control terminal 35 is electrically connected to the collector of the transistor 57, and the ground is electrically connected to the emitter. Therefore, for example, by switching the base voltage of the transistor 57 by a microcomputer built in the vehicle-side control circuit 55, the collector-emitter is made conductive (ON state) or non-conductive (OFF state). Can be controlled. That is, if the transistor 57 is off, no current flows through the coil 31. Therefore, the relay 23 selects the normally closed terminal 25 side. On the other hand, if the transistor 57 is in the on state, the switching terminal 33 is connected to the ground, so that a current flows from the main power supply 13 to the coil 31. As a result, the relay 23 is switched to the normally open terminal 27 side.

  Thus, the vehicle-side control circuit 55 is configured to perform switching control of the relay 23. Here, the switching signal SL is turned on when the transistor 57 is turned on and a current flows through the coil 31, and turned off when the transistor 57 is turned off and no current flows through the coil 31. Define.

  Next, the operation of the power storage device 11 will be described. When the use of the vehicle is started, the control circuit 53 outputs the charging signal CH to the charging circuit 49 in order to charge the power storage unit 47. In response to this, the charging circuit 49 charges the power storage unit 47 with the power of the main power supply 13. At this time, since the control circuit 53 detects the voltage Vc of the power storage unit 47 by the voltage detection circuit 51, if the power storage unit 47 reaches a predetermined voltage (for example, full charge voltage), the control circuit 53 On the other hand, it controls to stop charging. By this operation, the power storage unit 47 is charged in advance simultaneously with the use of the vehicle. In use of the vehicle, the relay 23 is switched to the normally closed terminal 25 in a normal state except when the engine (not shown) is restarted after idling stop, that is, a normally closed state. It is. Thereby, the electric power of the main power supply 13 is supplied to the load 15 at normal times.

  Next, the operation when the engine is restarted after the vehicle has stopped idling will be described with reference to FIG. In FIGS. 2A to 2E, the horizontal axis is time t. In FIG. 2A, the vertical axis represents voltage, the solid line represents the voltage Vo of the load terminal 19, and the long broken line represents the voltage Vb of the main power supply terminal 17.

  First, at time t0 during the idling stop, since the power of the main power supply 13 is supplied to the load 15, the switching signal SL is off as shown in FIG. 2 (b). Accordingly, since no current flows through the coil 31, the relay 23 selects the normally closed terminal 25 side as shown in FIG. As a result, as shown in FIG. 2A, the voltage Vo at the load terminal 19 is smaller than the voltage Vb at the main power supply terminal 17 by a relay voltage drop ΔVr caused by the internal resistance value of the relay 23. . However, since the voltage Vo at the load terminal 19 is sufficiently higher than the minimum voltage (hereinafter referred to as the predetermined voltage Vcm) for driving the load 15, the load 15 can be driven stably even during the idling stop. The predetermined voltage Vcm is 9 V in the present embodiment, although it depends on the specifications of the load 15. At time t0, as shown in FIGS. 2D and 2E, since both the second switch 41 and the first switch 39 are off, the power of the power storage unit 47 is supplied to the load 15. Not.

  Next, the idling stop ends at time t1. The vehicle-side control circuit 55 determines the end of the idling stop, for example, when the driver switches from the brake pedal to the accelerator pedal.

  When the vehicle-side control circuit 55 determines the end of the idling stop, it immediately turns on the transistor 57. As a result, as shown in FIG. 2B, the switching signal SL is turned on and input to the switching terminal 33. As a result, a current flows through the coil 31, and the relay 23 is switched from the normally closed terminal 25 to the normally open terminal 27. However, since this operation is performed mechanically, the relay 23 is not immediately switched. There will be a millisecond delay. Accordingly, when the switching signal SL is input, the control circuit 53 receives the first switch on / off signal at time t2 before the relay 23 performs the operation of switching to the normally open terminal 27 side, that is, to open. SW1 is output to the first switch 39 as an ON signal. As a result, the first switch 39 is turned on as shown in FIG.

  By such an operation, the first switch 39 is turned on at time t2, but the second switch 41 remains off, and the relay 23 still maintains the normally closed terminal 25 side. Here, since the FET voltage drop ΔVf due to the second parasitic diode 45 is larger than the relay voltage drop ΔVr, the power to the load 15 is still supplied from the main power supply 13.

  Thereafter, when reaching the time t3 (several milliseconds after the time t1) when the mechanical switching operation of the relay 23 is started, the relay 23 is connected to the normally closed terminal 25 and the The chattering operation reciprocates between the normally open terminals 27. As a result, as shown in FIG. 2A, the voltage Vo at the load terminal 19 fluctuates up and down. The voltage fluctuation width at this time is the FET voltage drop ΔVf. This is because the FET voltage drop ΔVf caused by the second parasitic diode 45 when the power of the power storage unit 47 is supplied to the load 15 when the relay 23 is switched to the normally open terminal 27 and is opened. This is because of this. Therefore, the voltage Vo of the load terminal 19 varies with the voltage width of the FET voltage drop ΔVf. However, if the electronic switch 37 is not provided as in the prior art, the voltage Vo at the load terminal 19 drops to 0 V when the relay 23 is switched, and the load 15 may not be driven sufficiently. On the other hand, in the present embodiment, even if the voltage Vo varies with the voltage width of the FET voltage drop ΔVf, as shown in FIG. 2A, the voltage is sufficiently higher than the predetermined voltage Vcm. The load 15 can be driven stably.

  Thereafter, the starter (not shown) is driven to restart the engine at time t4. As a result, the voltage Vb of the main power supply 13 is greatly reduced as shown by the long broken line in FIG. Therefore, after time t4, even if there is the FET voltage drop ΔVf due to the second parasitic diode 45, the voltage on the power storage unit 47 side becomes high. Therefore, the power of the power storage unit 47 is supplied to the load 15. At this time, as shown by a solid line in FIG. 2A, the voltage Vo of the load terminal 19 decreases with time as the power storage unit 47 is discharged, but maintains a voltage higher than the predetermined voltage Vcm. Therefore, the load 15 is continuously driven.

  Thereafter, at time t5 while the starter is being driven, the chattering of the relay 23 is finished as shown in FIG. 2C, and the switching to the normally open terminal 27 is completed. The power of the power storage unit 47 is supplied to the load 15 in the same manner as after time t4.

  Next, as shown by the long broken line in FIG. 2A, the voltage Vb of the main power supply 13 is minimized at time t6 as the starter is driven, but thereafter, the voltage Vb recovers. However, since the voltage does not immediately recover to the predetermined voltage Vcm, the power of the power storage unit 47 is continuously supplied to the load 15. As a result, the power storage unit 47 continues to discharge, and the voltage Vo of the load terminal 19 continues to decrease. Therefore, at time t7 after the relay 23 is opened, the control circuit 53 controls the second switch on / off signal SW2. Is output to the second switch 41 as an ON signal. As a result, the second switch 41 is turned on as shown in FIG. As a result, the FET voltage drop ΔVf due to the second parasitic diode 45 is eliminated, and the voltage Vo at the load terminal 19 is increased accordingly. Therefore, the period until the voltage Vo reaches the predetermined voltage Vcm can be lengthened, and the load 15 can be further stably driven. The second switch 41 may be turned on at the time t5 when the relay 23 is released and the chattering ends. However, in the present embodiment, the second switch 41 is added with a margin in consideration of an error in the chattering end time, etc. It is turned on at t7.

  Thereafter, the vehicle-side control circuit 55 approaches the transistor 57 at time t8 when the drive of the starter approaches completion and the voltage Vb of the main power supply 13 becomes sufficiently high as shown by the long broken line in FIG. Turn off. As a result, the switching signal SL input to the switching terminal 33 is turned off. However, as described above, the relay 23 is not immediately switched from the normally open terminal 27 to the normally closed terminal 25, and a delay of several milliseconds occurs. Therefore, immediately after time t8, power is continuously supplied from the power storage unit 47 to the load 15.

  Thereafter, the starter driving is completed at time t9, and the voltage Vb of the main power supply 13 gradually rises as shown by the long broken line in FIG. 2A, but several milliseconds have elapsed since time t8. At time t10, the relay 23 starts chattering. Thereby, at the moment when the relay 23 is switched to the normally closed terminal 25, both the first switch 39 and the second switch 41 are on, and as shown in FIG. Since the voltage Vb of 17 is larger than the voltage Vo of the load terminal 19, an inrush current flows from the main power supply 13 to the power storage unit 47 via the relay 23 and the electronic switch 37. As a result, the voltage Vo at the load terminal 19 rapidly rises to a value slightly lower than the voltage Vb at the main power supply terminal 17.

  Thereafter, when the relay 23 is switched to the normally open terminal 27 again by chattering, power is supplied from the power storage unit 47 to the load 15. In order to repeat such an operation, the voltage Vo at the load terminal 19 fluctuates up and down as shown by the solid line in FIG.

  Next, the chattering of the relay 23 ends at time t11 and switches to the normally closed terminal 25. This also causes the inrush current to flow into the power storage unit 47, so that the voltage Vo at the load terminal 19 rises at time t11 as shown by the solid line in FIG. If this inrush current is left as it is, a large current continuously flows and the fuse 21 may be blown. Therefore, as shown in FIG. 2 (d), the control circuit 53 performs the second switch at time t12. 41 is turned off.

  Time t12 is determined as follows. First, a period in which the fuse 21 is not blown after the time t11 (end of chattering of the relay 23) is obtained in advance as a predetermined period. Next, the time t12 is determined to be within the predetermined period after the time t11 (for example, 1/3 of the predetermined period). Thereby, although the said rush current flows temporarily, the said electrical storage apparatus 11 with little influence on the said fuse 21 grade | etc., Is realizable.

  When the second switch 41 is turned off at time t12, the current from the main power supply 13 to the power storage unit 47 is cut off by the second parasitic diode 45, and as shown in FIG. The voltage Vo of 19 is lower than the voltage Vb of the main power supply terminal 17 by the relay voltage drop ΔVr. Therefore, the power of the main power supply 13 is supplied to the load 15, and the stable operation is continued even after the idling stop.

  Next, the control circuit 53 turns off the first switch 39 as shown in FIG. 2E at time t13 after time t12 when the second switch 41 is turned off. Thereby, the electronic switch 37 is completely turned off.

  In the present embodiment, the second switch 41 is first turned off and then the first switch 39 is turned off. However, this may be turned off at the same time or in the reverse order. That is, when the switching signal SL is turned off, the first switch 39 and the second switch 41 are switched within the predetermined period after the relay 23 is switched so as to be normally closed (after time t11). The electronic switch 37 may be completely turned off by turning it off in any order. However, since the current to the power storage unit 47 can be interrupted as soon as possible by the second parasitic diode 45, the first switch 39 is turned off first, and then the first switch 39 is turned off. Is desirable.

  The operation of FIG. 2 described so far is summarized as follows. When the switching signal SL is input to the switching terminal 33, the control circuit 53 turns on the first switch 39 and opens the relay 23 before performing an operation of switching the relay 23 to open. Then, the second switch 41 is turned on. As a result, stable power can be supplied from the power storage unit 47 to the load 15 during the chattering period of the relay 23. Therefore, even if chattering occurs when the relay 23 is switched, the electronic switch 37 acts to stabilize the voltage Vo of the load terminal 19 by the power of the power storage unit 47. Further, since the power of the main power supply 13 is supplied to the load 15 via the relay 23 having a small internal resistance value except when the starter is driven, it is possible to reduce heat generation.

  After the idling stop (after time t13), in order to prepare for the next idling stop, the control circuit 53 charges the power storage unit 47 by the charging circuit 49 in the same manner as at the start of vehicle use. However, when there is a possibility that the power storage unit 47 supplies power to the load 15, that is, when the switching signal SL is input to the switching terminal 33, the control circuit 53 of the power storage unit 47 Charging is prohibited. This enables fast and efficient charging.

  2 is based on the premise that a sufficient amount of power is stored in the power storage unit 47. However, the idling stop may end during charging of the power storage unit 47, and the starter may be driven. is there. At this time as well, if the operation described with reference to FIG. 2 is performed, the inrush current flowing particularly from time t11 to time t12 increases. This is because if the voltage Vc of the power storage unit 47 is very low with respect to the voltage Vb of the main power supply 13, the voltage difference between the two becomes large. As a result, the fuse 21 may be blown.

  Therefore, in the present embodiment, at time t1 when the switching signal SL is input to the switching terminal 33, if the voltage Vc of the power storage unit 47 detected by the voltage detection circuit 51 is equal to or lower than the predetermined voltage Vcm, The control circuit 53 performs control so that the second switch 41 remains off even at time t7. Thereby, even if the voltage Vc of the power storage unit 47 is extremely low, the inrush current can always be blocked by the second parasitic diode 45, and the possibility of the fuse 21 being blown can be reduced. If the voltage Vc of the power storage unit 47 is equal to or lower than the predetermined voltage Vcm, sufficient power cannot be supplied from the power storage unit 47 to the load 15 while the starter is being driven. 15 will stop.

  To summarize the characteristic operations in the present embodiment described so far, the control circuit 53 has a period during which chattering occurs (time t3 to time t5, time t10 to time t11), and the relay 23 is In the period (time t5 to time t10) during which the normally open terminal 27 is switched, the electronic switch 37 is controlled to be turned on at a minimum.

  With the above configuration and operation, stable power can be supplied from the power storage unit 47 to the load 15 during the chattering period of the relay 23, and the power of the main power supply 13 passes through the relay 23 during normal times. Thus, a power storage device capable of reducing heat generation is obtained.

  In the present embodiment, the second switch 41 is constituted by the FET. However, this may be a diode electrically connected so as to be in the same direction as the second parasitic diode 45. As a result, while power is supplied from the power storage unit 47 to the load 15, the voltage drop of the diode always occurs and the loss increases, but the configuration and operation of the electronic switch 37 are simplified.

  Further, in the present embodiment, nothing is connected to the normally open terminal 27 of the relay 23, but this is electrically connected to the power storage unit 47 as shown by a long broken line in FIG. May be. That is, the relay 23 is electrically connected to the normally closed terminal 25 electrically connected to the main power supply terminal 17, a normally open terminal 27 electrically connected to the power storage unit 47, and the load terminal 19. And the common terminal 29 connected to the terminal. 2, when the relay 23 is switched to the normally open terminal 27 at time t5 in FIG. 2, the electric power of the power storage unit 47 is supplied to the load 15 via the relay 23, and the electronic switch 37 is turned on. A route to be supplied via is formed. At this time, as described above, since the relay voltage drop ΔVr is smaller than the FET voltage drop ΔVf, the electric power of the power storage unit 47 is supplied to the load 15 via the relay 23. Therefore, as shown by the thick dotted line in FIG. 2A, the voltage drop is small during the period from time t5 to time t7 when the second switch 41 is turned on as compared with the case where the normally open terminal 27 is not connected. Become. Therefore, stable power with less voltage fluctuation can be supplied to the load 15.

  When the second switch 41 is turned on at time t7, the internal resistance value of the electronic switch 37 is smaller than the internal resistance value of the relay 23 and can be almost ignored. It is supplied to the load 15 via the switch 37. Therefore, the operation after time t7 is the same as the operation when the normally open terminal 27 is not connected.

  Further, with such a configuration, since the electric power of the power storage unit 47 is supplied to the load 15 through the normally open terminal 27 during the period from time t5 to time t10 in FIG. During this period, the electronic switch 37 may be turned off. In this case, the electronic switch 37 is on only during the chattering generation period of the relay 23. Therefore, in the above configuration, the electronic switch 37 is controlled so as to be turned on only during the chattering period, or the relay 23 is connected to the normally open terminal 27 during the chattering period. It may be controlled so as to be turned on in both periods of the period of switching to.

  For these reasons, the electronic switch 37 may be controlled to be on at least during a period in which the relay 23 is generating chattering.

  Further, in the present embodiment, the relay 23 having the normally open terminal 27 is used, but this may be a relay without a normally open terminal.

  In the present embodiment, an electric double layer capacitor is used for the power storage unit 47, but this may be another capacitor such as an electrochemical capacitor or a secondary battery.

  Further, in the present embodiment, the example in which the power storage device 11 is applied to an idling stop vehicle has been described. However, the present invention is not limited to this, and the power storage device 11 is applied to a power backup system when the vehicle is started or when the main power supply is abnormal. be able to.

  Since the power storage device according to the present invention can achieve both stabilization of the voltage to the load and reduction of heat generation, the power storage device is useful as a power storage device as an auxiliary power supply that supplies power from the power storage unit when the voltage of the main power supply decreases.

1 is a block circuit diagram of a power storage device in an embodiment of the present invention. FIG. 4 is a voltage aging diagram and a timing chart of the power storage device according to the embodiment of the present invention, (a) is a chronological diagram of the voltage Vb of the main power supply terminal and the voltage Vo of the load terminal, and (b) is a timing chart of the switching signal. , (C) is a timing chart of the relay, (d) is a timing chart of the second switch, and (e) is a timing chart of the first switch. Block diagram of a conventional power supply Block circuit diagram of other configuration of conventional power supply device

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Power storage device 13 Main power supply 15 Load 17 Main power supply terminal 19 Load terminal 23 Relay 25 Normally closed terminal 27 Normally open terminal 29 Common terminal 33 Switching terminal 37 Electronic switch 39 1st switch 41 2nd switch 43 1st parasitic diode 45 2nd Parasitic diode 47 Power storage unit 49 Charging circuit 51 Voltage detection circuit 53 Control circuit

Claims (6)

A power storage unit;
A main power supply terminal electrically connected to the main power supply;
A load terminal electrically connected to the load;
A relay that is electrically connected between the main power supply terminal and the load terminal, receives a switching signal , and normally closes when the switching signal is off ;
An electronic switch electrically connected between the load terminal and the power storage unit;
A control circuit electrically connected to the relay and the electronic switch;
With
The electronic switch is composed of a first switch composed of a field effect transistor and a series circuit of second switches,
Electrically connected so that the cathode of the first parasitic diode of the first switch is on the power storage unit side, and the cathode of the second parasitic diode of the second switch is on the load terminal side,
The control circuit includes:
When the switching signal is turned on, the first switch is turned on and the second switch is turned off before performing the operation of switching so that the relay is opened and during the period when the relay is chattering.
The first switch and the second switch are turned on after the relay is opened.
Power storage device. A voltage detection circuit electrically connected to the power storage unit and the control circuit;
If the voltage (Vc) of the power storage unit detected by the voltage detection circuit is equal to or lower than a predetermined voltage (Vcm) when the switching signal is turned on , the control circuit keeps the second switch off. The power storage device according to claim 1 , wherein: The control circuit is configured to turn off the first switch and the second switch within a predetermined period after performing an operation of switching the relay to be normally closed when the switching signal is turned off. Item 2. The power storage device according to Item 1 . The power storage device according to claim 3 , wherein the control circuit first turns off the second switch and then turns off the first switch. A charging circuit electrically connected between the main power supply terminal and the power storage unit, and also electrically connected to the control circuit;
The power storage device according to claim 1 , wherein the control circuit prohibits charging of the power storage unit when the switching signal is turned on . The relay is a normally closed terminal electrically connected to the main power supply terminal;
A normally open terminal electrically connected to the power storage unit;
The power storage device according to claim 1, further comprising a common terminal electrically connected to the load terminal.

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