CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0141712 filed on Oct. 22, 2021, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a reflector for a bifacial solar module and a bifacial photovoltaic system and, more particularly, to a reflector for a bifacial solar module configured to produce electricity using light energy from the sun and a bifacial photovoltaic system including the same.

2. Discussion of Related Art

A bifacial light-receiving solar module generates power by not only absorbing direct light at a front surface but also absorbing light at a back surface due to light reflection of a reflecting panel installed on a bottom surface or a side surface.

To this end, in a cell unit, instead of existing back surface field (BSF) back electrodes, a grid type back surface electrode configured to transmit light is required. Also, while manufacturing a module, a transparent back sheet or a glass back cover is applied instead of an oblique back sheet.

An amount of light coming into a back surface is greatly influenced by albedo determined according to a type and properties of the reflecting panel. When a bifacial module is used, it is possible to expect an additional generation quantity according to the albedo of the reflecting panel. Generally, in an existing constructed bifacial light-receiving solar module, a reflecting panel utilizing a rolled aluminum plate is installed on an entirety of a lower end of the solar module or a small reflector is fixed to a lower end while a structure is constructed so that reflection efficiency increases.

Related thereto, Korean Patent Registration No. 2149746 (hereinafter, referred to as Related Art Document) discloses a generation device using an outdoor bifacial solar module. The generation device using the outdoor bifacial solar module in the related art document includes a photovoltaic device and a solar reflector.

Such photovoltaic devices are installed to be tilted in a direction toward sunlight and fixed at certain intervals. The photovoltaic device includes a bifacial module. The bifacial module is installed to adjust a tilt angle using an angle adjustment fixing device according to an elevation angle of the sun for each season.

The solar reflector is installed between adjacent photovoltaic devices. The solar reflector is configured to reflect sunlight toward a back surface of a bifacial module at an angle of reflection through a reflective mirror formed of a convex mirror so as to allow the bifacial module to generate power.

However, the generation device using the bifacial solar module in the Related Art Document has a disadvantage that adjustment of an angle of the reflective mirror according to variations in the elevation angle of the sun for each season depends on manipulation of an administrator. Accordingly, since the elevation angle of the sun varies everyday, a method of responding to the variations in the elevation angle of the sun actively is required.

The sunlight includes not only direct light transferred to an object directly without reflection or scattering but also scattered light in a direction changed by scattering due to clouds, fine dust, other objects, and the like. An amount and an incident angle of scattered light may vary according to environmental factors such as clouds, fine dust, other objects, and the like.

However, the reflective mirror of the generation device using the bifacial solar module in the related art document has a limitation in that the reflective surface forms a uniform reflective surface such that only direct light is reflected toward the back surface of the bifacial module but reflection efficiency of scattered light is insignificant.

Accordingly, the generation device using the bifacial solar module in the related art document has a limitation in improvement of power generation performance through bifacial light reception due to an excessive difference of reflexibility toward the back surface of the bifacial module which is caused by environmental factors. Accordingly, a method of significantly improving reflection efficiency toward the back surface of the bifacial module is required.

RELATED ART DOCUMENT

[Patent Document]

Korean Patent Registration No. 2149746 (registered on Aug. 25, 2020)

SUMMARY OF THE INVENTION

The present invention is directed to providing a reflector for a bifacial solar module configured so that a position and an angle of a reflective surface are automatically adjusted according to variations of an elevation angle of the sun and not only direct light but also scattered light are reflected toward back surfaces of the bifacial solar module so as to maximize power generation performance of the bifacial solar module, and the photovoltaic system including the same.

According to an aspect of the present invention, there is provided a reflector for a bifacial solar module. The reflector includes a reflecting panel configured to reflect sunrays toward back surfaces of a first bifacial solar module and a second bifacial solar module which are located higher than the ground, a mobile cart configured to support the reflecting panel and be movable below and between the first bifacial solar module and the second bifacial solar module, and a control portion configured to control a position of the mobile cart to maximize power generation amounts of the first bifacial solar module and the second bifacial solar module.

A position value of the mobile cart according to an elevation angle of the sun may be set in the control portion, and the control portion may control a position of the mobile cart according to the elevation angle of the sun.

The control portion may receive real-time power generation amounts of the first bifacial solar module and the second bifacial solar module. Also, the control portion may control a position of the mobile cart to be a position where the power generation amounts of the first bifacial solar module and the second bifacial solar module are maximized.

Rails, along which wheels of the mobile cart roll, may be provided lengthwise in a direction in which the first bifacial solar module and the second bifacial solar module are spaced apart from each other.

Rails, along which wheels of the mobile cart roll, may be provided lengthwise in a direction perpendicular to a direction in which the first bifacial solar module and the second bifacial solar module are spaced apart from each other.

The mobile cart may include a controller configured to receive a signal from the control portion and a driving portion configured to rotate the wheels according to a signal of the controller.

The driving portion may include a motor rotatable bidirectionally according to the signal of the controller. Torque of the motor may be transmitted to a rotating shaft of the wheels through gear drive, chain drive, or belt transmission.

The mobile cart may include a controller configured to receive a signal from the control portion and a driving portion configured to rotate the wheels according to a signal of the controller.

The driving portion may include a motor rotatable bidirectionally according to the signal of the controller. Torque of the motor may be transmitted to a rotating shaft of the wheels through gear drive, chain drive, or belt transmission.

The reflecting panel may include a first reflection portion configured to reflect sunrays toward the first bifacial solar module and a second reflection portion configured to reflect sunrays toward the second bifacial solar module. Also, a reflective surface of the first reflection portion and a reflective surface of the second reflection portion may be plane-symmetrical to each other.

The reflective surface of the first reflection portion and the reflective surface of the second reflection portion may form a curved surface.

The first reflection portion may include a 1-1 reflection portion configured to form a reflective surface facing the sky and a 1-2 reflection portion configured to form a reflective surface forming an obtuse angle with the reflective surface of the 1-1 reflection portion.

The second reflection portion may include a 2-1 reflection portion configured to form a reflective surface facing the sky and configured to be plane-symmetrical to the 1-1 reflection portion and a 2-2 reflection portion configured to form a reflective surface forming an obtuse angle with the reflective surface of the 2-1 reflection portion and configured to be plane-symmetrical to the 1-2 reflection portion. Also, the reflective surface of the 1-2 reflection portion and the reflective surface of the 2-2 reflection portion may form a reflex angle.

The reflecting panel may be rotatably coupled to the mobile cart. Also, the mobile cart includes a controller configured to receive a signal from the control portion and an angle adjustment module configured to rotate the reflecting panel according to a signal of the control portion.

The angle adjustment module may include a motor rotatable bidirectionally according to the signal of the controller. Torque of the motor may be transmitted to a rotating shaft of the reflecting panel through gear drive, chain drive, or belt transmission.

According to another aspect of the present invention, there is provided a bifacial photovoltaic system including a first bifacial solar module spaced apart from the ground and having a front surface facing the sky, a second bifacial solar module spaced apart from the ground and having a front surface facing the sky, a reflecting panel configured to reflect sunrays toward back surfaces of the first bifacial solar module and the second bifacial solar module, a mobile cart configured to support the reflecting panel and be movable below and between the first bifacial solar module and the second bifacial solar module, and a control portion configured to control a position of the mobile cart to maximize power generation amounts of the first bifacial solar module and the second bifacial solar module.

