Solar power generating system

Abstract

To provide a solar power generating system capable of preventing overheat of an ECU.SOLUTION: A solar power generating system 10 includes a solar panel mounted on a roof outer surface of a vehicle, an ECU which is arranged between a roof lining and the solar panel, and controls driving of the solar panel, and a cooling fan for air-cooling the ECU, wherein when the temperature of the solar panel is equal to or higher than a regulated threshold temperature, an exhaust heat wind direction of the cooling fan is switched to the cabin side, and when the temperature of the solar panel is lower than the threshold temperature, the exhaust heat wind direction of the cooling fan is switched to the solar panel side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This specification discloses a solar power generation system that generates power using a solar panel mounted on a vehicle. [Background technology]

[0002] Vehicles equipped with solar panels have been known for some time now. In addition to the solar panels, such vehicles are equipped with a battery that stores generated electricity, an electronic control unit (hereinafter referred to as "ECU") that controls the operation of the solar panels, and the like.

[0003] Here, the battery and the ECU generate heat and reach high temperatures as they are driven. If the battery and the ECU become excessively hot, they may break down. For this reason, air-cooling the battery or the ECU has been proposed.

[0004] For example, Patent Document 1 discloses that a cooling fan is provided to cool the battery, and when the battery temperature is equal to or higher than a threshold, charging of the battery is stopped and the cooling fan is operated. This technology makes it possible to prevent the battery from overheating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-090266 Summary of the Invention [Problem to be solved by the invention]

[0006] However, overheating of the ECU is not fully considered in Patent Document 1. Therefore, this specification discloses a solar power generation system that can prevent overheating of the ECU. [Means for solving the problem]

[0007] The solar power generation system disclosed in this specification comprises a solar panel attached to the outer surface of a vehicle roof, an ECU arranged between the roof lining and the solar panel and controlling the operation of the solar panel, and a cooling fan for air-cooling the ECU, and is characterized in that when the temperature of the solar panel is equal to or higher than a specified threshold temperature, the exhaust air direction of the cooling fan is switched to the passenger compartment side, and when the temperature of the solar panel is below the threshold temperature, the exhaust air direction of the cooling fan is switched to the solar panel side. Effect of the Invention

[0008] According to the solar power generation system disclosed in this specification, overheating of the ECU is effectively prevented. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a solar power generation system. [Diagram 2] 10 is a flowchart showing a flow of a solar panel cooling process. [Diagram 3] FIG. 13 is a schematic diagram showing the configuration of another example of a solar power generation system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The solar power generation system 10 will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of the solar power generation system 10, and is a diagram showing a schematic cross section of the periphery of the roof of a vehicle. In each figure, "Fr", "Up", and "Rh" indicate the front, upper, and right side of the vehicle, respectively.

[0011] The solar power generation system 10 includes a solar panel 12 and an ECU 20. The solar panel 12 is a power generation device that generates power by receiving irradiation of sunlight, and is typically a solar cell module that is an assembly of solar cells. The amount of power generated by the solar panel 12 depends on the solar radiation intensity. The power generated by the solar panel 12 is output to and stored in a battery (not shown) for solar power generation. The vehicle uses the power charged in the battery to drive auxiliary equipment and a driving motor.

[0012] The solar panel 12 is attached to the outer surface of the roof of the vehicle. In the example of Fig. 1, the solar panel 12 is formed by attaching sheet-shaped solar cells to the outer surface of the roof panel of the vehicle. Therefore, in the example of Fig. 1, the solar panel 12 is integrated with the roof panel.

[0013] The temperature of the solar panel 12 rises depending on the solar radiation conditions and power generation conditions. The temperature sensor 18 detects the temperature of the solar panel 12. Hereinafter, the temperature of the solar panel 12 detected by the temperature sensor 18 is referred to as the "panel temperature Tp." The detected panel temperature Tp is sent to the ECU 20. The number and positions of the temperature sensors 18 may be changed as appropriate. For example, a plurality of temperature sensors 18 may be provided. In this case, a statistical value (e.g., an average value or a median value) of a plurality of detected temperatures obtained by the plurality of temperature sensors 18 may be treated as the panel temperature Tp. In addition, although the temperature sensor 18 is disposed on the back surface of the solar panel 12 in FIG. 1, the temperature sensor 18 may be provided in another location, for example, on the front surface of the solar panel 12. In addition, the temperature sensor 18 may be a non-contact temperature sensor that detects the temperature without contact.

[0014] The ECU 20 is disposed below the solar panel 12. More specifically, a roof lining 14 that functions as a ceiling for the vehicle compartment is disposed below the solar panel 12, with a space in between. The ECU 20 is disposed in the space between the roof lining 14 and the solar panel 12 (hereinafter referred to as "disposition space 16").

[0015] The ECU 20 controls the operation of the solar panel 12 and the battery. The ECU 20 is physically a computer having a processor and a memory (neither of which is shown). The processor, memory, and other electronic elements are housed in a housing. The housing is formed with a first ventilation hole 21f and a second ventilation hole 21s for passing air between the inside and outside of the housing. The first ventilation hole 21f faces the solar panel 12, and the second ventilation hole 21s faces the roof lining 14. In the example of FIG. 1, the first ventilation hole 21f is formed at one end of the housing in the longitudinal direction, and the second ventilation hole 21s is formed at the other end of the housing in the longitudinal direction. The ECU 20 is disposed in such a position that its longitudinal axis is inclined with respect to the horizontal plane. However, it is needless to say that the arrangement of the first ventilation hole 21f and the second ventilation hole 21s may be changed as appropriate. For example, the first ventilation hole 21f may be disposed on the top surface of the housing, and the second ventilation hole 21s may be disposed on the bottom surface of the housing.

[0016] A cooling fan 22 is attached near the first ventilation hole 21f. The cooling fan 22 is an electric fan for forcibly cooling the ECU 20. That is, the ECU 20 generates heat as it is driven, and the temperature rises. If the ECU 20 becomes excessively hot, there is a risk of the ECU 20 breaking down. Therefore, the air from the cooling fan 22 is used to exhaust the heat from the ECU 20 and cool the ECU 20.

[0017] The cooling fan 22 can rotate in both forward and reverse directions. When rotating forward, the cooling fan 22 draws in air inside the ECU 20. In this case, air is generated from the second air vent 21s through the inside of the ECU 20 toward the first air vent 21f. This air removes heat from the ECU 20 as it passes through the inside of the ECU 20. Then, the exhaust hot air is discharged from the cooling fan 22 toward the solar panel 12. That is, when the cooling fan 22 rotates forward, the exhaust hot air flows in the direction of arrow A in FIG. 1, toward the solar panel 12.

[0018] In addition, in the case of reverse rotation, the cooling fan 22 sends air into the inside of the ECU 20. In this case, air is generated from the first air vent 21f through the inside of the ECU 20 toward the second air vent 21s. Then, the exhaust hot air is discharged from the second air vent 21s toward the roof lining 14. That is, in the case of reverse rotation of the cooling fan 22, the exhaust hot air flows in the direction of the arrow B in FIG. 1, toward the passenger compartment.

[0019] The cooling fan 22 is driven and controlled by the ECU 20. The ECU 20 switches the rotation direction of the cooling fan 22, and therefore the direction of the exhaust heat air, depending on the panel temperature Tp. Specifically, when the panel temperature Tp is less than a predefined threshold temperature Tth, the ECU 20 rotates the cooling fan 22 forward. When the panel temperature Tp is equal to or higher than the threshold temperature Tth, the ECU 20 rotates the cooling fan 22 in the reverse direction. As a result, when the solar panel 12 is at a low temperature, the exhaust heat air flows toward the solar panel 12, and when the solar panel 12 is at a high temperature, the exhaust heat air flows toward the passenger compartment. The reason for this configuration will be explained.

[0020] Normally, the heat of the ECU 20 is released outside the vehicle. Therefore, normally, the hot air exhausted from the ECU 20 is directed towards the solar panel 12. As a result, the heat exhausted from the ECU 20 is released outside the vehicle via the solar panel 12. However, as described above, the temperature of the solar panel 12 changes significantly depending on the solar radiation conditions, etc. For example, if the vehicle is left under the blazing sun in summer, the panel temperature Tp becomes significantly higher than the temperature of the hot air. In this case, if the hot air exhausted from the ECU 20 is directed towards the solar panel 12, the temperature around the ECU 20 will rise, and the intended cooling effect for the ECU 20 will not be achieved.

[0021] Therefore, in this example, when the panel temperature Tp is equal to or higher than a specified threshold temperature Tth, the cooling fan 22 is rotated in the reverse direction to switch the exhaust air direction to the passenger compartment. Since the heat of the ECU 20 is released to the passenger compartment, which has a low temperature, the ECU 20 can be appropriately cooled even when the solar panel 12 is at a high temperature.

[0022] Here, the threshold temperature Tth may be determined in advance by experiment or simulation based on the amount of heat generated by the ECU 20, the upper limit temperature of the components used in the ECU 20, the space size of the arrangement space 16, etc. The threshold temperature Tth may be a fixed value that does not change, or may be a variable value that changes according to various conditions. For example, a separate temperature sensor (not shown) may be provided inside the ECU 20, and the threshold temperature Tth may be changed so that the higher the detected temperature of the ECU 20, the higher the threshold temperature Tth becomes.

[0023] Fig. 2 is a flowchart showing the flow of control for switching the exhaust heat air direction. As shown in Fig. 2, the ECU 20 compares the panel temperature Tp with the threshold temperature Tth (S10). If the comparison result shows that the panel temperature Tp is less than the threshold temperature Tth (Yes in S10), the ECU 20 rotates the cooling fan 22 in the forward direction and sets the exhaust heat air direction to the solar panel 12 (S12). On the other hand, if the panel temperature Tp is equal to or greater than the threshold temperature Tth, the ECU 20 rotates the cooling fan 22 in the reverse direction and switches the exhaust heat air direction to the passenger compartment side (S14). Thereafter, the same process is repeated.

[0024] As is clear from the above description, in the case of the solar power generation system 10 disclosed in this specification, the direction of the exhaust air from the ECU 20 is switched according to the temperature of the solar panel 12, so that the ECU 20 can be more appropriately cooled. Note that the configuration described so far is merely an example, and other configurations may be changed as long as the configuration described in claim 1 is included.

[0025] For example, in the above description, the direction of the exhaust heat air is changed by changing the rotation direction of the cooling fan 22. However, the direction of the exhaust heat air may be changed by using other members. For example, as shown in FIG. 3, the cooling fan 22 may always rotate in the forward direction, and a movable louver 24 may be provided on the exhaust side of the cooling fan 22. The direction of the exhaust heat air may be changed by changing the direction of the louver 24 according to the panel temperature Tp. FIG. 3 shows a state in which the exhaust heat air direction is set to the passenger compartment side. When the panel temperature Tp becomes equal to or higher than the threshold temperature Tth, the louver 24 rotates 90 degrees from the state shown in FIG. 3. The arrangement of the cooling fan 22 and the vents 21f and 21s may also be changed as appropriate.

[0026] In the above description, the temperature of the solar panel 12 is detected by the temperature sensor 18. However, the temperature of the solar panel 12 may be obtained without using the temperature sensor 18. For example, the temperature of the solar panel 12 may be estimated based on the power generation status of the solar panel 12, the weather, and the like. For example, the temperature of the solar panel 12 changes according to the solar radiation intensity, and the amount of solar power generation changes according to the solar radiation intensity. Therefore, the temperature of the solar panel 12 may be estimated based on the amount of solar power generation. For example, when the amount of solar power generation equal to or greater than a predetermined reference value continues for a predetermined reference time or longer, it may be estimated that the temperature of the solar panel 12 exceeds the threshold temperature Tth. [Explanation of symbols]

[0027] 10 solar power generation system, 12 solar panel, 14 roof lining, 16 arrangement space, 18 temperature sensor, 20 ECU, 22 cooling fan, 24 louver.

Claims

[Claim 1] a solar panel attached to an outer surface of the roof of the vehicle; an ECU disposed between a roof lining and the solar panel for controlling the driving of the solar panel; A cooling fan for cooling the ECU; when the temperature of the solar panel is equal to or higher than a specified threshold temperature, the exhaust air direction of the cooling fan is switched to the vehicle compartment side, and when the temperature of the solar panel is lower than the threshold temperature, the exhaust air direction of the cooling fan is switched to the solar panel side. A solar power generation system comprising:

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