JP2017160891A - Power supply device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device for a vehicle which can start a vehicle drive system without waiting for charge to an auxiliary battery.SOLUTION: A starting battery unit 20 comprises: a lithium-ion battery (LIB) 21; a microcontroller 23 which is operable with a lead battery 5 mounted to a vehicle or the LIB 21 as a power supply; and a changeover circuit 22 which can switch an electricity-carrying state between an electric apparatus E and the LIB 21, and an electricity-carrying state between the microcontroller 23 and the LIB 21. The microcontroller 23 controls the changeover circuit 22 so as to be switched to a first state that the LIB 21 and the microcontroller 23 are carried with electricity when the power of the lead battery 5 is shorted, and controls the changeover circuit 22 so as to be switched to a second state that the electric apparatus E and the LIB 21 are carried with electricity in response to simultaneous operations of a brake pedal BP and a start switch 12 in the first state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle power supply device applied to a vehicle drive system for driving a vehicle such as a hybrid vehicle or an electric vehicle.

  A lead-acid battery and a lithium-ion battery, and as a vehicle power supply device used in a vehicle drive system, when the lead-acid battery system fails to start, the lithium-ion battery is used to start charging the lead battery for a predetermined time. One that prompts the driver to restart the system later is known (see Patent Document 1).

JP 2008-180207 A

  The device of Patent Document 1 has room for improvement because it takes time from the start of charging the lead battery to the restart of the vehicle drive system.

  Accordingly, an object of the present invention is to provide a vehicle power supply device that can start a vehicle drive system without waiting for charging of an auxiliary battery.

  The vehicle power supply device of the present invention is a vehicle power supply device applied to a vehicle including an auxiliary battery electrically connected to an electric device used when starting the vehicle drive system. Control means operable with a machine battery or the auxiliary battery as a power source, and switching means capable of switching between an energization state between the electric device and the auxiliary battery and an energization state between the control means and the auxiliary battery, respectively. The control means controls the switching means to switch to a first state in which the auxiliary battery and the control means are energized when the power of the auxiliary battery is insufficient, and relates to starting in the first state. The switching means is controlled to switch to a second state in which the electric device and the auxiliary battery are energized in response to a user's specific operation.

  According to the vehicle power supply device of the present invention, when the power of the auxiliary battery is insufficient, the power of the control means is ensured by switching to the first state in which the control means and the auxiliary battery are energized. Then, in the first state, the electric device and the auxiliary battery are switched to the second state in response to the user's specific operation related to the start, and the auxiliary battery becomes a power source of the electric device used for starting the vehicle drive system. . Therefore, since the operation of the electric device is ensured by the auxiliary battery when the power of the auxiliary battery is insufficient, the vehicle drive system can be started without waiting for charging of the auxiliary battery.

The figure which showed typically the principal part of the electric system of the vehicle to which the power supply device for vehicles which is one form of this invention was applied. The flowchart which showed an example of the control routine of the power supply device for vehicles. The figure which showed the time change of the voltage of each battery at the time of vehicle leaving.

  FIG. 1 shows an electric system of a hybrid vehicle as an example of the vehicle. The hybrid vehicle includes an HV main battery 1 used as a power source for a motor / generator (not shown). The HV main battery 1 is electrically connected to a DCDC converter 3 via a system main relay 2. Accordingly, the DCDC converter 3 supplied with power from the HV main battery 1 is also used for charging the lead battery 5 via the auxiliary power supply circuit C. In the following description, “connection” means electrical connection unless otherwise specified. In addition, a thick solid line in FIG. 1 means a power supply wiring, and a thin arrow line means an input / output of an electric signal.

  An auxiliary power supply circuit C is connected to the DCDC converter 3. A lead battery 5 as an auxiliary battery is connected to the auxiliary power circuit C, and various types of electricity used for starting a vehicle drive system including an internal combustion engine (not shown) and a motor / generator mounted on the hybrid vehicle. Device E is connected. The electrical equipment E controls the system main relay 2 and the HVECU 6 that comprehensively controls the hybrid vehicle, the ID code box 7 that performs access key verification for theft prevention, and the anti-theft steering lock device. A steering lock ECU 8, a verification ECU 9 that exchanges electrical signals with these devices 6 to 8, and other devices 10. The hybrid vehicle is provided with a stop lamp switch 11 that is turned ON / OFF in conjunction with the operation of the brake pedal BP operated by the user, and a start switch 12 that is operated by the user. The output signals of 11 and 12 are input to the verification ECU 9.

  The auxiliary power supply circuit C is connected to a starting battery unit 20 as a vehicle power supply device. The starting battery unit 20 includes a lithium ion battery (hereinafter referred to as LIB) 21 as an auxiliary battery, a switching circuit 22 as switching means, and a microcontroller (hereinafter referred to as MC) 23 as control means. . The LIB 21 is configured by combining, for example, four 18650 type battery cells. The switching circuit 22 switches between the power supply to the auxiliary machine power circuit C and the power supply to the MC 23, so that the latching type relay A for switching the energization state between the electric equipment E and the LIB 21 and the energization between the MC 23 and the LIB 21 are switched. And a latching type relay B for switching the state.

  The MC 23 is designed so that the LIB 21 having the above specifications can monitor the LIB 21 for a sufficient period of time, for example, the average current consumption is about 0.1 mA. Further, the driving of the MC 23 is guaranteed up to a voltage (for example, 5 V) lower than the starting limit voltage (for example, 8.5 V) of the hybrid vehicle (see FIG. 3).

  The MC 23 is configured to operate with a predetermined logic. Although the detailed operation will be described later, the MC 23 is connected to the relay B so that its power supply can be obtained from the LIB 21 when the voltage of the auxiliary power circuit C decreases to near the above drive guarantee voltage, that is, when the power of the lead battery 5 is insufficient. Is switched from the OFF state shown in the drawing to the ON state to switch to the first state in which the MC 23 and the LIB 21 are energized. Further, in this first state, the MC 23 responds to the simultaneous operation of the depression operation of the brake pedal BP and the ON operation of the start switch 12 which is a specific operation by the user regarding the start, and each of the stop lamp switch 11 and the start switch 12. When the output signal is input, the relay A is switched from the OFF state shown to the ON state to switch to the second state in which the electric device E and the LIB 21 are energized.

  Details of the operation of the MC 23 are as shown in the flowchart of FIG. Note that the relay A and the relay B are both assumed to be OFF at the start of the flowchart of FIG. As shown in FIG. 2, in step S <b> 1, the MC 23 compares the voltage of the auxiliary power circuit C (auxiliary voltage) with the charging voltage due to the operation of the DCDC converter 3 to determine whether or not the DCDC converter 3 is stopped. Determine. If the DCDC converter 3 is stopped, the process proceeds to step S2, and if not, the process proceeds to step S8. When the DCDC converter 3 is stopped, the situation is almost the same as that when the vehicle is parked.

  In step S2, the MC 23 determines whether or not the auxiliary machine voltage Va is less than the drive guarantee voltage Vc of the MC 23, and continues the process of step S2 to continue monitoring the auxiliary machine voltage. If the auxiliary voltage is less than the drive guarantee voltage, the process proceeds to step S3. The case where the auxiliary machine voltage is less than the drive guarantee voltage corresponds to the case where the power of the lead battery 5 is insufficient.

  In step S3, the MC 23 supplies power to the relay B of the switching circuit 22 and controls the relay A to be in an OFF state and the relay B to be in an ON state. As a result, the state in which the energization between the MC 23 and the LIB 21 is cut off is switched to the first state in which the MC 23 and the LIB 21 are energized.

  In step S4, the MC 23 determines whether or not the brake pedal BP is depressed and the start switch 12 is turned on as the user's specific operation related to the start. Is detected, and this process is continued to monitor the presence or absence of the specific operation. If there is a specific operation by the user, the process proceeds to step S5.

  In step S5, the MC 23 supplies power to the relay A of the switching circuit 22 and controls both the relay A and the relay B to be in an ON state. As a result, the relay A and the relay B are both in the ON state, and the LIB 21 and the auxiliary power supply circuit C are switched to the second state in which power is supplied. By switching to the second state, power is supplied to the electric equipment E used for starting the vehicle drive system, and the normal start operation of the vehicle drive system is performed by the HVECU 6 or the like.

  In step S6, the MC 23 compares the auxiliary machine voltage and the charging voltage as in step S1, and determines whether or not the DCDC converter 3 is in operation. If the DCDC converter 3 is in operation, it can be determined that the vehicle drive system has been successfully started, and the routine is terminated. On the other hand, when the DCDC converter 3 is stopped, it can be determined that the start of the vehicle drive system has failed because the electric power E cannot be sufficiently supplied, and the process proceeds to step S7.

  In step S7, the MC 23 once controls the relay A of the switching circuit 22 from the ON state to the OFF state, and returns the process to step S4. In step S6, the MC 23 confirms the successful start of the vehicle drive system. The process of step S6 is repeatedly executed.

  In step S8, the MC 23 determines whether or not the auxiliary machine voltage Va is lower than the voltage Vb of the LIB 21. If the auxiliary machine voltage Va is lower than the voltage Vb of the LIB 21, the process proceeds to step S9, where the relay of the switching circuit 22 is relayed. Both A and relay B are controlled to be in an OFF state, and the process returns to step S1. On the other hand, if the auxiliary machine voltage Va is equal to or higher than the voltage Vb of the LIB 21, both the relay A and the relay B of the switching circuit 22 are controlled to be turned on, the LIB 21 is charged, and the process returns to step S1.

  Next, an example of operation when the hybrid vehicle of this embodiment is left unattended will be described with reference to FIG. Actually, the voltage drop is not proportional to the time depending on the discharge amount, but in order to help understanding of the operation, the voltage is expressed by a linear change in FIG. As shown in FIG. 3, when the vehicle is left unattended, when the voltage of the lead battery 5 decreases due to self-discharge, dark current, deterioration, etc. of the lead battery 5 and reaches the drive guarantee voltage Vc of the MC 23 at time t1, MC23 And the first state in which the LIB 21 is energized, and the power source of the MC 23 is switched to the LIB 21. As a result, the voltage of the LIB 21 gradually decreases due to the self-discharge and the decrease in the power storage rate due to the driving of the MC 23, but the driving of the MC 23 and the electric device E until the time t2 when the hybrid vehicle starting limit voltage Vp is reached. Can be kept in a possible state. The self-discharge of LIB 21 is about a 1% decrease in voltage per year. On the other hand, assuming a vehicle with only the lead battery 5 and no LIB 21, in that case, the operation of the electric device E is ensured at the time t0 when the voltage of the lead battery 5 reaches the start limit voltage Vp. Otherwise, the vehicle drive system cannot be started. Therefore, in the case of the hybrid vehicle of this embodiment, the time for which the vehicle drive system can be started is greatly increased as compared with a vehicle equipped with only the lead battery 5.

  According to the present embodiment, when the auxiliary machine voltage is less than the drive guarantee voltage and the power of the lead battery 5 is insufficient, the MC 23 and the LIB 21 are switched to the first state in which power is supplied, thereby securing the power source of the MC 23. . Then, in the first state, the electric device E and the LIB 21 are switched to a second state in which the electric device E and the LIB 21 are energized in response to the simultaneous depression of the brake pedal BP for starting and the ON operation of the start switch 12. Power source. Therefore, when the electric power of the lead battery 5 is insufficient, the operation of the electric device E is ensured without waiting for the LIB 21 to charge the lead battery 5, so that the vehicle drive system can be started.

  This invention is not limited to the said form, It can implement with a various form within the range of the summary of this invention. In the above embodiment, a lead battery is provided as an auxiliary battery and a lithium ion battery is provided as an auxiliary battery. However, the present invention can also be applied to a vehicle employing other types of batteries. Moreover, the said form is provided with the starting battery unit 20 which LIB21, the switching circuit 22, and MC23 were combined as a vehicle power supply device, and the attachment etc. to an existing vehicle etc. are easy to replace | exchange. However, the present invention does not necessarily have to be implemented in units. For example, the present invention can be implemented in a form in which these configurations are distributed and arranged in a vehicle.

  In the above embodiment, the present invention is applied to a hybrid vehicle. In addition to the internal combustion engine, various vehicles such as a conventional vehicle having no traveling drive source, an electric vehicle, a plug-in hybrid vehicle, and a fuel cell vehicle are driven. The present invention can also be implemented in a form applied to the vehicle drive system for

5 Lead battery (auxiliary battery)
20 Start-up battery unit (vehicle power supply)
21 Lithium ion battery (auxiliary battery)
22 Switching circuit (switching means)
23 Microcontroller (control means)
E Electrical equipment

Claims (1)

In a vehicle power supply device applied to a vehicle including an auxiliary battery electrically connected to an electric device used at the start of a vehicle drive system,
An auxiliary battery;
Control means operable with the auxiliary battery or the auxiliary battery as a power source;
Switching means capable of switching between the energized state of the electrical device and the auxiliary battery and the energized state of the control means and the auxiliary battery, and
With
The control means controls the switching means so as to switch to a first state in which the auxiliary battery and the control means are energized when the power of the auxiliary battery is insufficient, and a user related to starting in the first state. A vehicle power supply device that controls the switching means so as to switch to a second state in which the electric device and the auxiliary battery are energized in response to the specific operation.

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