Solar charging system

Abstract

To provide a solar charging system that can suppress deterioration of a component life by improving energy efficiency in a vehicle.SOLUTION: A solar charging system mounted on a vehicle, comprises: a power generation module using a solar panel; an auxiliary-machine battery for storing generated power of the power generation module; a driving battery used for driving the vehicle; and a control unit provided between the driving battery and the auxiliary-machine battery and controlling power transmission between the two batteries. The control unit changes an amount of power from the auxiliary-machine battery to be transmitted to the driving battery on the basis of a vehicle state when performing processing to transmit power to the driving battery from the auxiliary-machine battery.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a solar charging system that controls the supply of electric power generated by a solar panel mounted on a vehicle.

Background Art

[0002] Patent Document 1 discloses a solar charging system in which, when a solar panel is in a power generation state, first, power is supplied from the solar panel to an auxiliary machine system to derive the actual generated power of the solar panel. If the derived generated power is equal to or greater than a specified value that can efficiently charge the auxiliary machine system, the drive battery is charged with the generated power of the solar panel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a vehicle, in order to efficiently use the electric power generated by a solar panel or the electric power stored in an auxiliary battery, power may be transferred from the auxiliary battery to the drive battery. On the other hand, in a situation where solar power generation is not expected, such as when stored for a long time at night or in the absence of sunlight, power is transferred from the drive battery to the auxiliary battery in order to prevent the auxiliary battery from rising due to dark current.

[0005] However, such an act of power transfer between the auxiliary battery and the drive battery causes deterioration of energy efficiency due to power loss associated with the step-up / step-down operation of the DCDC converter, and deterioration of the lifespan of components such as relays and electronic control units (ECUs) related to power transfer. Therefore, there is room for further consideration regarding the method of power transfer between the auxiliary battery and the drive battery.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a solar charging system that can improve energy efficiency in a vehicle and suppress deterioration of component life.

Means for Solving the Problems

[0007] In order to solve the above problems, one aspect of the disclosed technology is a solar charging system mounted on a vehicle, including a power generation module using a solar panel, an auxiliary battery that stores the generated power of the power generation module, a driving battery used for driving the vehicle, and a control unit provided between the driving battery and the auxiliary battery to control power transfer between the two batteries. When performing a process of transferring power from the auxiliary battery to the driving battery, the control unit changes the amount of power of the auxiliary battery transferred to the driving battery based on the state of the vehicle.

Effects of the Invention

[0008] According to the solar charging system of the present disclosure, when transferring power from the auxiliary battery to the driving battery, the remaining power amount of the auxiliary battery is changed based on the state of the vehicle. Therefore, if the remaining power amount of the auxiliary battery is increased, the amount of power transferred to the driving battery is decreased, so the power transferred back to the auxiliary battery is suppressed. Therefore, energy efficiency is improved and deterioration of component life is suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiment for Carrying out the Invention

[0010] When the solar charging system according to the present disclosure transfers power from the auxiliary battery to the driving battery, when the vehicle is in a state where solar radiation cannot be expected, such as at night or in a garage, the remaining power of the auxiliary battery is increased, and the power transferred from the auxiliary battery to the driving battery is decreased. Thereby, the power pumped out from the driving battery to the auxiliary battery can be suppressed to prevent the auxiliary battery from rising. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] <Embodiment> [Configuration] FIG. 1 is a block diagram showing a schematic configuration of a solar charging system 1 according to an embodiment of the present disclosure. The solar charging system 1 illustrated in FIG. 1 includes a solar power generation module 10, a driving battery 20, an auxiliary battery 30, a bidirectional DCDC converter 40, and a dedicated DCDC converter 50. This solar charging system 1 is mounted on a vehicle such as a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), and an electric vehicle (BEV), for example.

[0012] The solar power generation module 10 is a power generation device that generates power by receiving sunlight, and outputs the generated power to an auxiliary battery 30, an auxiliary load 100, etc. connected to the solar power generation module 10. This solar power generation module 10 includes a solar panel that is an aggregate of solar cells, a solar DCDC converter that outputs the power generated by the solar panel at a predetermined voltage, a solar control unit that executes maximum power point tracking (MPPT) control, etc. (not shown). The generated power of the solar panel is calculated from the measured values of sensors and measuring instruments (not shown).

[0013] The driving battery 20 is a rechargeable secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. This driving battery 20 is connected to a main device (not shown) for driving the vehicle and can supply the electric power necessary for the operation of this main device. Examples of the main device include a starter motor and a driving electric motor. Further, the driving battery 20 is connected to the solar power generation module 10 via a bidirectional DCDC converter 40 so that it can be charged by the electric power generated by the solar panel. Furthermore, the driving battery 20 is connected to the auxiliary battery 30 via a dedicated DCDC converter 50 so that it can charge the auxiliary battery 30 with the electric power it stores when the vehicle is parked or the like. The driving battery 20 is a high-voltage battery with a rated voltage higher than that of the auxiliary battery 30.

[0014] The auxiliary battery 30 is a rechargeable secondary battery such as a lithium-ion battery or a lead-acid battery. This auxiliary battery 30 can supply the electric power necessary for the operation of the auxiliary load 100 to the auxiliary load 100. The auxiliary battery 30 is connected to the solar power generation module 10 so that it can be charged by the electric power generated by the solar panel. Also, the auxiliary battery 30 is connected to the bidirectional DCDC converter 40 so that it can be charged by the electric power stored in the driving battery 20. Furthermore, the auxiliary battery 30 is connected to the driving battery 20 via a dedicated DCDC converter 50 so that electric power can be supplied from the driving battery 20 in order to avoid battery overcharge when a leakage current is flowing through the auxiliary load 100 during parking of the vehicle or the like. Note that the charge amount (storage amount) of the auxiliary battery 30 is monitored by a sensor or a measuring instrument (not shown).

[0015] The bidirectional DC-DC converter 40 is a bidirectional power converter (first DC-DC converter) that can convert the input power into power of a predetermined voltage and output it. One end of this bidirectional DC-DC converter 40 (referred to as the primary side) is connected to the solar power generation module 10, the auxiliary battery 30, and the auxiliary load 100, and the other end (referred to as the secondary side) is connected to the driving battery 20. The bidirectional DC-DC converter 40 can supply (pumping charge) the power of the auxiliary battery 30 connected to the primary side to the driving battery 20 connected to the secondary side. FIG. 4 shows an example of the power transfer path when supplying power from the auxiliary battery 30 to the driving battery 20. Also, the bidirectional DC-DC converter 40 can supply the power of the driving battery 20 connected to the secondary side to the auxiliary battery 30 and the auxiliary load 100 connected to the primary side. During this power supply, the bidirectional DC-DC converter 40 boosts the output voltage of the auxiliary battery 30, which is the input voltage on the primary side, to the output voltage on the secondary side (during boost operation), and also steps down the voltage of the driving battery 20, which is the input voltage on the secondary side, to the output voltage on the primary side (during buck operation). Note that instead of the bidirectional DC-DC converter 40, two unidirectional DC-DC converters may be provided with the power transfer direction reversed.

[0016] The dedicated DC-DC converter 50 is a power converter (second DC-DC converter) that can convert the input power into power of a predetermined voltage and output it. The input side end of this dedicated DC-DC converter 50 is connected to the driving battery 20, and the output side end is connected to the solar power generation module 10, the auxiliary battery 30, and the auxiliary load 100. The dedicated DC-DC converter 50 can step down the power input from the driving battery 20 and supply it to the auxiliary battery 30 (buck operation). FIG. 5 shows an example of the power transfer path when supplying power from the driving battery 20 to the auxiliary battery 30 when the vehicle is parked. Note that the role of this dedicated DC-DC converter 50 may be assigned to the bidirectional DC-DC converter 40.

[0017] The above-described bidirectional DCDC converter 40 and dedicated DCDC converter 50, together with an electronic control unit (not shown) that controls the operation of these DCDC converters, etc., constitute a control unit that controls power transfer between the driving battery 20 and the auxiliary battery 30. The control executed by this control unit will be described later.

[0018] The auxiliary load 100 is various auxiliary devices mounted on the vehicle. The auxiliary load 100 operates by receiving the power generated by the solar power generation module 10 or the power stored in the auxiliary battery 30. Examples of such auxiliary devices include lighting devices such as headlamps and interior lights, air conditioning devices such as heaters and air conditioners, and systems for autonomous driving and advanced driver assistance.

[0019] [Control] Next, with further reference to FIGS. 2 and 3, the control performed in the solar charging system 1 according to the present embodiment will be described. FIG. 2 is a flowchart for explaining the processing procedure of the charging control during power transfer executed by the solar charging system 1. FIG. 3 is a diagram for explaining an example of the change in the remaining power amount of the auxiliary battery 30.

[0020] The charging control during power transfer illustrated in FIG. 2 is started when the state of the vehicle becomes a state in which power is transferred from the auxiliary battery 30 to the driving battery 20 (the charging state of the driving battery 20).

[0021] (Step S201) The solar charging system 1 determines whether there is a request to save the charge amount of the auxiliary battery 30. This request to save the charge amount of the auxiliary battery 30 is a request to limit the charge amount (electric power amount) transferred from the auxiliary battery 30 to the driving battery 20 in order to charge the driving battery 20, and to make the remaining electric power amount in the auxiliary battery 30 more than usual after the power transfer process is performed.

[0022] Situations where a request to save the charge level of the auxiliary battery 30 is made can include cases where the solar power generation module 10 cannot generate a predetermined amount of power. The predetermined amount of power is, for example, power such that even when the process of charging the auxiliary battery 30 with the generated power of the solar panel is performed, the power consumption of components such as the ECU required for the charging process does not exceed the generated power, and the energy efficiency does not deteriorate. Vehicle states where the solar power generation module 10 cannot generate a predetermined amount of power or where power generation cannot be expected include cases where the time is in the night time zone (such as between sunset and sunrise), cases where the weather is cloudy or rainy, states where the solar radiation amount is less than a predetermined amount (such as when parked in a garage with a roof), cases where the vehicle is stored (parked, transported, etc.) for a predetermined period or more, and cases where components related to the charging process in the vehicle are malfunctioning. Alternatively, even when there is a predetermined instruction (such as an instruction not to use solar power generation) from the vehicle user or the like, it may be a vehicle state where the solar power generation module 10 cannot generate a predetermined amount of power.

[0023] When the solar charging system 1 determines that there is a request to save the charge level of the auxiliary battery 30 (step S201, yes), the process proceeds to step S202. On the other hand, when the solar charging system 1 determines that there is no request to save the charge level of the auxiliary battery 30 (step S201, no), the process proceeds to step S203.

[0024] (Step S202) The solar charging system 1 sets (adjusts) the threshold value for controlling the charge amount (electric energy amount) transferred from the auxiliary battery 30 to the drive battery 20 to the first threshold value. As shown in FIG. 3, this first threshold value is a threshold value for limiting and reducing the charge amount transferred from the auxiliary battery 30 to the drive battery 20 compared to normal times. When the charge amount transferred from the auxiliary battery 30 to the drive battery 20 by the solar charging system 1 is set to the first threshold value, the process proceeds to step S204.

[0025] (Step S203) The solar charging system 1 sets (adjusts) the threshold value for controlling the amount of charge (electric energy) transferred from the auxiliary battery 30 to the driving battery 20 to a second threshold value. As shown in FIG. 3, this second threshold value is a threshold value for transferring the amount of charge from the auxiliary battery 30 to the driving battery 20 without limitation. Therefore, the second threshold value is set to a value smaller than the above-described first threshold value. When the amount of charge transferred from the auxiliary battery 30 to the driving battery 20 by the solar charging system 1 is set to the second threshold value, the process proceeds to step S204.

[0026] (Step S204) The solar charging system 1 executes power transfer from the auxiliary battery 30 to the driving battery 20. As a result, the driving battery 20 is charged with the amount of electric energy of the auxiliary battery 30 determined by the first threshold value or the second threshold value. When the power transfer from the auxiliary battery 30 to the driving battery 20 is executed by the solar charging system 1, the charge control at the time of this power transfer ends.

[0027] <Function and Effect> As described above, according to the solar charging system 1 according to an embodiment of the present disclosure, when power is transferred from the auxiliary battery 30 to the driving battery 20, when the time is in the night time zone, when it is stored for a long time in a state where the solar radiation amount cannot be ensured, when a component related to the charging process fails, or when there is an instruction from the user to stop solar power generation, the amount of charge transferred from the auxiliary battery 30 to the driving battery 20 is controlled (adjusted) to be less than normal to increase the amount of electric energy remaining in the auxiliary battery 30.

[0028] By this control, for example, when power generation by the solar charging system 1 is not expected, the opportunity to transfer power from the driving battery 20 to the auxiliary battery 30 again to prevent the increase of the auxiliary battery 30 can be reduced. Therefore, the energy efficiency is improved, and the deterioration of the life (number of ON / OFF times, etc.) of components such as relays and electronic control units (ECUs) can be suppressed.

[0029] The above describes an embodiment of the disclosed technology. The present disclosure can be regarded not only as a solar charging system, but also as a charging control method during power transfer, a control program for the method, a computer-readable non-transitory storage medium storing the control program, a vehicle equipped with the solar charging system, and the like.

Industrial Applicability

[0030] The solar charging system of the present disclosure can be used in vehicles equipped with solar panels and the like.

Explanation of Signs

[0031] 1 Solar charging system 10 Solar power generation module 20 Driving battery 30 Auxiliary battery 40 Bidirectional DCDC converter 50 Dedicated DCDC converter 100 Auxiliary load

Claims

1. A solar charging system mounted on a vehicle, comprising: a power generation module using a solar panel; an auxiliary battery for storing the generated power of the power generation module; a driving battery used for driving the vehicle; a control unit provided between the driving battery and the auxiliary battery for controlling power transfer between the two batteries; The control unit: includes a first DC-DC converter capable of supplying the power of the auxiliary battery to the driving battery and capable of supplying the power of the driving battery to the auxiliary battery; includes a second DC-DC converter for supplying the power of the driving battery to the auxiliary battery while the vehicle is parked; when performing a process of transferring power from the auxiliary battery to the driving battery, changes the amount of power of the auxiliary battery transferred to the driving battery based on the state of the vehicle. A solar charging system.

2. When the power generation module cannot generate a predetermined amount of power as the state of the vehicle, the control unit reduces the amount of power of the auxiliary battery transferred to the driving battery compared to when the power generation module can generate the predetermined amount of power. The solar charging system according to Claim 1.

3. When the state of the vehicle is a time period or weather in which power generation cannot be expected, when the vehicle has been stored for a predetermined period or more in a state where the solar radiation amount is less than a predetermined amount, when a component related to the charging process in the vehicle is malfunctioning, and when there is a predetermined instruction for the vehicle, if it is at least one of these cases, the control unit reduces the amount of power of the auxiliary battery transferred to the driving battery compared to cases other than the at least one case. The solar charging system according to Claim 2.

4. A solar charging system mounted on a vehicle, comprising: a power generation module using a solar panel; an auxiliary battery for storing the generated power of the power generation module; a driving battery used for driving the vehicle; a control unit provided between the driving battery and the auxiliary battery for controlling power transfer between the two batteries; The control unit: includes a DC-DC converter capable of bidirectionally transferring power between the auxiliary battery and the driving battery. When performing a process of transferring electric power from the auxiliary battery to the drive battery, the amount of electric power of the auxiliary battery transferred to the drive battery is changed based on the state of the vehicle. When the power generation module cannot generate a predetermined amount of electric power as the state of the vehicle, the amount of electric power of the auxiliary battery transferred to the drive battery is made less than that when the power generation module can generate the predetermined amount of electric power. Solar charging system.

5. When the state of the vehicle is a time zone or weather in which power generation cannot be expected, when the vehicle has been stored for a predetermined period or more in a state where the solar radiation amount is less than a predetermined amount, when a component related to the charging process in the vehicle has failed, and when there is a predetermined instruction for the vehicle, if it is at least one of these cases, the amount of electric power of the auxiliary battery transferred to the drive battery is made less than that in cases other than the at least one of these cases. The solar charging system according to claim 4.

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