JP5728864B2 - Solar cell module - Google Patents

Description

  The present invention relates to a dye-sensitized solar cell, and more particularly to the structure and arrangement of solar cells.

  In recent years, expectations for solar cells have increased, and among them, dye-sensitized solar cells (DSCs) have attracted attention. The dye-sensitized solar cell has various advantages such as being able to be manufactured by extending printing technology, being easy to mold, and being excellent in design because various colors can be realized. When light is applied to a cell of a dye-sensitized solar cell (hereinafter simply referred to as “cell”), the dye in the cell is excited and the dye emits electrons. The emitted electrons are taken out from a cathode called a working electrode. The electrons return to the anode called the counter electrode via an external load. The function of the battery is exhibited when the dye repeats electron emission and electron absorption.

JP 2004-119902 A JP 2009-238583 A

  In order to increase the power generation efficiency of the cell, it is necessary to increase the area of the portion where the cell receives light (hereinafter referred to as “effective power generation area”). It is also important to be able to efficiently place cells on the outer surfaces of various products that utilize dye-sensitized solar cells. For that purpose, it is desirable to be able to prepare cells of various sizes and shapes.

  The electromotive force of the cell of the dye-sensitized solar cell is usually about 0.3 to 0.7 (V). When the electromotive force of one cell is insufficient, a plurality of cells are connected in series. In order to increase the power generation efficiency of this series circuit, it is necessary to match the electrical characteristics such as the internal resistance and impedance of each cell.

  The present invention has been completed in view of the above-mentioned problems, and its main object is to propose a cell structure and arrangement that can easily achieve both power generation efficiency and design of a dye-sensitized solar cell. .

  A solar cell submodule according to the present invention includes a plurality of cells of a dye-sensitized solar cell that generates electrons from a working electrode provided on a daylighting surface side and takes electrons from a counter electrode provided on a non-lighting surface side. A connection conductor for connecting a plurality of cells in series is provided by connecting a working electrode of the second cell and a counter electrode of a second cell different from the first cell. Each cell is arranged rotationally symmetrically with respect to the first axis, and the plurality of cells form all or part of the radial shape body.

  By arranging a plurality of cells rotationally symmetrically with respect to the first axis, a solar cell sub-module that forms all or part of the radial solar cell centering on the first axis is formed. According to such a structure, the freedom degree of design of a dye-sensitized solar cell can be expanded. In addition, by aligning the central angle of each cell with respect to the first axis, it becomes easy to equalize the cell size, and thus the electrical characteristics.

The shape of each cell may be a sector having the same central angle with respect to the first axis. The term “ identical” here means, for example, the degree of identity that allows a deviation of around 5%. The same applies to the meaning of the term “abbreviated” below.

  The effective power generation area of each cell may be substantially the same. By aligning the effective power generation area, the electromotive force of each cell can be easily made uniform.

  The inner partition that separates the electrolyte contained in each of the plurality of cells may be formed thinner than the outer partition that separates the electrolyte from the outside. By reducing the inner partition wall of the cell, the effective power generation area can be further increased. Further, by increasing the thickness of the external partition, it becomes easier to protect the cell from external stress.

  The solar cell module according to the present invention includes a plurality of the solar cell submodules described above. In this solar cell module, a plurality of solar cell submodules are connected in series by connecting the positive terminal of the first solar cell submodule and the negative terminal of the second solar cell submodule.

  A solar cell module is formed by connecting a plurality of solar cell submodules in series. According to such a configuration, the electromotive force and shape of the solar cell module can be flexibly changed according to the number of solar cell modules used.

  Each solar cell submodule is disposed rotationally symmetrically with respect to a second axis that is the central axis of the solar cell module. All or part of the radial shape body is formed by the plurality of solar cell submodules. According to such a configuration, the range of design of the dye-sensitized solar cell can be expanded.

  The shape of each solar cell sub-module may be a fan shape having substantially the same central angle with respect to the second axis.

  When the width of the outer partition wall is W1 and the width of the inner partition wall is W2, the first axis may be set at a position offset from the second axis by W1- (W2 / 2). .

  By providing such an offset, the effective power generation area of each cell can be easily made uniform in design. Details will be described later.

  In the timepiece according to the present invention, the dial of the analog timepiece is formed on the daylighting surface of the solar cell module. Alternatively, the second axis may be set at the center of the dial, and the center angle of each cell with respect to the first axis may be set to approximately 30 degrees.

  According to the present invention, it becomes easy to achieve both the power generation efficiency and the design of the dye-sensitized solar cell.

It is a schematic sectional drawing of the cell of a dye-sensitized solar cell. It is a schematic perspective view of the submodule of a dye-sensitized solar cell. It is a schematic diagram which shows the connection method of a working electrode electrically conductive film and a counter electrode electrically conductive film. It is a top view of the module of a dye-sensitized solar cell. It is an enlarged plan view of the module in the vicinity of the center point. It is a schematic diagram for demonstrating the drawing method of the cell in a module. FIG. 7 is a design drawing of a module drawn according to the drawing method of FIG. 6. It is an external view of the timepiece which applied the module in this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view of a cell of a dye-sensitized solar cell. In FIG. 1, the structure and principle of one cell 100 will be described. The right direction in the figure is the positive direction of the x-axis, the upward direction is the positive direction of the z-axis, and the direction from the paper surface to the back is the positive direction of the z-axis. The cell 100 in FIG. 1 generates power by the light 200 from the lower direction in the figure. The light 200 is emitted in the positive direction of the z axis.

  The structure of the cell 100 is as follows. In the cell 100, the counter electrode conductive film 110 is provided on the counter electrode side substrate 108 on the non-lighting surface side. The counter electrode side substrate 108 and the counter electrode conductive film 110 are collectively referred to as “counter electrode”. The material of the counter electrode side substrate 108 is glass, plastic or the like. As a material of the counter electrode conductive film 110, a metal, a conductive oxide, or the like can be used. Since the counter electrode side substrate 108 is a non-lighting surface side substrate, it may not be a light-transmitting material. A catalyst layer 126 is provided on the surface of the counter electrode conductive film 110. It is preferable to use platinum (Pt) as the catalyst.

  A working electrode conductive film 104 is disposed on the working electrode side substrate 102 on the light-collecting surface side. The material of the working electrode conductive film 104 is preferably a light-transmitting conductive material such as tin-doped indium oxide (ITO) or fluorine-doped tin oxide (FTO). The working electrode side substrate 102 needs to use a light transmissive material such as glass or plastic.

  A space partitioned by the working electrode conductive film 104, the counter electrode conductive film 110, and the partition 112 is filled with an electrolyte 116, and a metal oxide layer 114 is formed on the surface of the working electrode conductive film 104. The electrolyte 116 is an electrolytic solution in which iodine (I2) is dissolved. As the material of the metal oxide layer 114, titanium oxide (TiO2) and zinc oxide (ZnO) can be used. The metal oxide layer 114 is formed to be porous, and the dye 118 is adsorbed. The material of the partition 112 is resin, glass, or the like. The metal oxide layer 114, the working electrode conductive film 104, and the working electrode side substrate 102 are collectively referred to as a “working electrode”. The distance from the working electrode conductive film 104 to the counter electrode conductive film 110, that is, the thickness of the space is about 1 to 300 μm.

  The operating principle of the cell 100 is as follows. The light 200 transmitted through the working electrode side substrate 102 and the working electrode conductive film 104 excites the dye 118 of the metal oxide layer 114, and the dye 118 emits electrons. Electrons are emitted to the working electrode conductive film 104. Although details will be described later, the electrons emitted to the working electrode conductive film 104 are supplied to the counter electrode conductive film 110 of the adjacent cell 100. Electrons supplied from the adjacent cell 100 reach the electrolyte 116 from the counter electrode conductive film 110. The electrons oxidize iodine ions in the electrolyte 116, and the iodine ions are reduced by the dye 118. Hereinafter, in the present embodiment, description will be made assuming that the electromotive force of one cell 100 is 0.5 (V).

  FIG. 2 is a schematic perspective view of the submodule 130. The sub-module 130 (hereinafter simply referred to as “sub-module 130”) of the dye-sensitized solar cell in the present embodiment includes three cells 100a, 100b, and 100c. Each cell 100 has a fan shape with a central angle of 30 degrees, and the submodule 130 has a fan shape with a central angle of 90 degrees. That is, all the cells 100 are arranged in rotational symmetry with respect to the virtual first axis 132. The position of the first axis 132 in the xy plane is called an aggregation point P. From the left side of the figure, cells 100a, 100b, and 100c are connected in this order.

  A negative electrode terminal 134 is drawn from the working electrode conductive film 104 on the upper side of the cell 100a, that is, on the daylighting surface side. The counter electrode conductive film 110 of the cell 100a is connected to the working electrode conductive film 104 of the cell 100b via a connecting conductor (not shown). The counter electrode conductive film 110 of the cell 100b is connected to the working electrode conductive film 104 of the cell 100c. A positive electrode terminal 136 is drawn from the counter electrode conductive film 110 of the cell 100c.

  As a result, the three cells 100 are connected in series between the negative terminal 134 and the positive terminal 136. When the electromotive force of one cell 100 is 0.5 (V), the electromotive force of the submodule 130 as a whole is 0.5 × 3 = 1.5 (V). Note that the effective power generation areas of the cells 100 are substantially the same. This is to suppress variation in electrical characteristics such as impedance and increase the power generation efficiency of the submodule 130 as a whole. Details will be described later with reference to FIG.

  FIG. 3 is a schematic diagram showing a method of connecting the working electrode conductive film 104 and the counter electrode conductive film 110. Both the working electrode conductive film 104 and the counter electrode conductive film 110 have a sector shape. A protrusion 122a is provided at one end of the outer peripheral portion of the counter electrode conductive film 110a, and a section 124a is provided at the other end. Similarly, a protrusion 140a is provided at one end of the outer peripheral portion of the working electrode conductive film 104a, and a section 142a is provided at the other end. The protrusion 140a of the working electrode conductive film 104b of the adjacent cell 100b enters the segment 142a of the working electrode conductive film 104a of the cell 100a. Further, the protrusion 122a of the counter electrode conductive film 110a of the cell 100a faces the protrusion 140b of the working electrode conductive film 104b of the adjacent cell 100b. Here, by connecting the protrusion 122a of the counter electrode conductive film 110a and the protrusion 140b of the working electrode conductive film 104b with a conductor (connecting conductor), free electrons flowing into the working electrode conductive film 104b from the metal oxide layer 114 can be obtained. , Can be supplied to the counter electrode conductive film 110a of the adjacent cell 100a. By such a connection method, a “battery” in which a plurality of cells 100 are connected in series can be formed.

  FIG. 4 is a plan view of the module 150. The dye-sensitized solar cell module 150 (hereinafter simply referred to as “module 150”) in the present embodiment includes four sub modules 130a to 130d. Since the submodule 130 is a fan-shaped object having a central angle of 90 degrees, the shape of the module 150 is a perfect circle. The positive terminal 136 of the submodule 130a is connected to the negative terminal 134 of the adjacent submodule 130b. Similarly, the positive terminal 136 of the submodule 130b is connected to the negative terminal 134 of the submodule 130c, and the positive terminal 136 of the submodule 130c is connected to the negative terminal 134 of the submodule 130d. The negative terminal 134 and the positive terminal 136 of the module 150 as a whole are drawn from the sub modules 130a and 130d, respectively.

  Since three cells 100 are connected in series in the submodule 130, 3 × 4 = 12 cells 100 are connected in series in the entire module 150. When the electromotive force of one cell 100 is 0.5 (V), the electromotive force of the entire module 150 is 0.5 × 12 = 6.0 (V).

  In order to ensure the operational stability of the submodule 130, it is necessary to prevent entry of moisture and oxygen from the outside into the cell 100 and leakage of the electrolyte 116 inside the cell 100. Each cell 100 is separated by a partition 112. In the present embodiment, the partition 112 (external partition) located on the outer wall portion of the cell 100 is thick, and the partition 112 (internal partition) located on the connection portion between the cell 100 and the cell 100 is thinner. This is because the external partition wall is easily subjected to external stress, and the internal partition wall is not easily subjected to such stress. Therefore, even if the inner partition wall is made thinner than the outer partition wall, the robustness of the cell 100 is not so much impaired. Further, if the inner partition wall is made thinner, the area of the metal oxide layer 114, in other words, the effective power generation area can be easily increased. When the thickness of the external partition wall is W1 and the thickness of the internal partition wall is W2, it is desirable that W1> W2.

  The center point of the module 150 is O. Needless to say, the submodules 130 are arranged so as to be rotationally symmetric with respect to the second axis passing through the center point O. However, a slight deviation (offset) is provided between the center point O of the module 150 and the aggregation point P of each submodule 130. Details will be described later with reference to FIG.

  FIG. 5 is an enlarged plan view of the module 150 in the vicinity of the center point O. FIG. FIG. 5 particularly shows the vicinity of the aggregation point Pa of the submodule 130a. If the coordinates of the center point O are the origin (0, 0), the coordinates of the aggregation point Pa of the submodule 130a are set to (W1-W2 / 2, W1-W2 / 2). The coordinates of the aggregation point Pb of the submodule 130b are (W1-W2 / 2, -W1 + W2 / 2), the coordinates of the aggregation point Pc of the submodule 130c are (-W1 + W2 / 2, -W1 + W2 / 2), and the aggregation of the submodule 130d. The coordinates of the point Pd are (−W1 + W2 / 2, W1−W2 / 2).

  In the present embodiment, the outer partition wall thickness W1 = 2.5 (mm), the inner partition wall thickness W2 = 1.5 (mm), the outer diameter of the module 150 itself = 87.5 (mm), the inner diameter = 16. Suppose that it is 5 (mm). When the aggregation point Pa is set at the above position, the effective power generation areas of the cell 100a and the cell 100c are both 326.6 (square mm) and the effective power generation area of the cell 100b is 323.1 (square mm). became.

  On the other hand, when the aggregation point Pa and the center point O are matched, the effective power generation areas of the cells 100a and 100c are both 314.8 (square mm), and the effective power generation area of the cell 100b is 364.2 (square mm). )

  That is, it is easier to make the effective power generation areas of the cells 100a to 100c uniform by shifting the aggregation point Pa from the center point O by (W1-W2 / 2, W1-W2 / 2). Although the total effective power generation area of the submodule 130a as a whole is slightly reduced due to the offset, the power generation efficiency of the submodule 130a as a whole is increased by making the effective power generation area uniform. In terms of design, it is preferable that the shape and area of each cell 100 can be unified.

  FIG. 6 is a schematic diagram for explaining a method of drawing the cell 100 in the module 150. The outer radius of the module 150 is R1, and the inner radius is R4. The distance from the center point O to the outer periphery of the effective power generation region of the cell 100 is R2, and the distance from the center point O to the inner periphery of the effective power generation region of the cell 100 is R3. Since the thickness of the external partition is W1, R1 = R2 + W1 and R4 = R3-W1. Here, a drawing method related to the sub-module 130a in the first quadrant will be described.

1. The aggregation point Pa is set at a position shifted from the center point O by d = W1-W2 / 2.
2. A first arc 160 having a radius R1-s (2) × d and a central angle of 90 degrees is drawn with the aggregation point Pa as the center. Here, s (2) represents the square root of 2 and is about 1.414. Since the distance between the aggregation point Pa and the center point 0 is s (2) × d, the radius of the first arc 160 drawn around the aggregation point Pa is R1−s (2) × d. Strictly speaking, the first arc 160 does not coincide with the outer edge of the module 150.
3. A second arc 162 of R1−s (2) × d−W1 is drawn around the aggregation point Pa.
4). A fourth circular arc 166 having a radius R4-s (2) × d and a central angle of 90 degrees is drawn around the aggregation point Pa.
5. A third arc 164 having a radius R4-s (2) × d + W1 is drawn around the aggregation point Pa.
6). A trisection straight line 168 is drawn that divides each arc having a central angle of 90 degrees into three equal parts.
7.3 By setting the width of the equally dividing line 168 to W2, the inner partition wall region is determined.
8). By setting the x-axis and y-axis widths to 2 × W1, the external partition wall region is set.

  The same applies to the second to fourth quadrants. Since the center point O and each aggregation point Pa do not coincide with each other, the through hole in the center portion does not need to be a perfect circle. FIG. 7 is a design diagram of the module 150 drawn by the above drawing method.

  FIG. 8 is an external view of a timepiece 170 to which the module 150 according to this embodiment is applied. The surface of the watch 170 is a daylighting surface. For this reason, it is possible to capture light from almost the entire surface of the watch face. The central angles of the cells 100 are all unified at 30 degrees. Since the position of the internal partition wall corresponds to the time interval, there is also an advantage that it does not cause a sense of incongruity in design. In addition, it is preferable from the viewpoint of aesthetics to arrange the inner partition walls symmetrically.

  In general, the cells of a dye-sensitized solar cell are often formed in a rectangular shape (see Patent Document 1). Patent Document 2 proposes a circular cell, but it is difficult to secure a sufficient electromotive force because it is a single cell. On the other hand, the dye-sensitized solar cell module 150 in this embodiment forms a circular module 150 by combining a large number of fan-shaped cells. Thereby, the variation of a design can be expanded, ensuring sufficient electromotive force. The module 150 in this embodiment is circular, but may have other radial shapes such as a polygon. In this case, the shape of the cell 100 may be a trapezoid or a triangle. According to the module 150 in the present embodiment, the dye-sensitized solar cell can be adapted to various radiation shapes as well as the conventional rectangular type.

  The module 150 includes a plurality of submodules 130, and the submodule 130 includes a plurality of cells 100. Since the module 150 is formed by the combination of the submodules 130, it has a feature of excellent portability. The number of submodules 130 included in one module 150 is arbitrary. When forming the catalyst layer 126, a vacuum film forming apparatus is used. When the submodule 130 is large, it is necessary to use a large-scale vacuum film forming apparatus. Therefore, from the viewpoint of the manufacturing process of the submodule 130, it is preferable that the submodule 130 is small. On the other hand, from the viewpoint of the assembly process of the submodule 130, the submodule 130 is preferably larger. Therefore, the optimum values for the number and size of the submodules 130 may be determined based on manufacturing conditions and work conditions.

  The present invention has been described based on the embodiments. It will be understood by those skilled in the art that the embodiments are illustrative, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. By the way. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive.

  100 cells, 102 working electrode side substrate, 104 working electrode conductive film, 108 counter electrode side substrate, 110 counter electrode conductive film, 112 partition, 114 metal oxide layer, 116 electrolyte, 118 dye, 122 protrusion, 124 slice, 126 catalyst Layer, 130 sub-module, 132 first axis, 134 negative terminal, 136 positive terminal, 140 protrusion, 142 section, 150 module, 160 first arc, 162 second arc, 164 third arc, 166 fourth arc, 168 Trisection straight line, 170 clock, 200 light.

Claims (8)

A plurality of solar cell submodules having a plurality of cells of a dye-sensitized solar cell that generates electrons from a working electrode that is an electrode provided on the daylighting side and takes in electrons from a counter electrode that is an electrode provided on the non-lighting side A solar cell module comprising:
The solar cell submodule includes a connection conductor that connects the plurality of cells in series by connecting a working electrode of the first cell and a counter electrode of a second cell different from the first cell, and each The cell is rotationally symmetric with respect to a first axis perpendicular to the working electrode;
The solar cell submodule passes through the center point of the solar cell module and is arranged rotationally symmetrically with respect to a second axis perpendicular to the working electrode.
The solar cell module, wherein the first axis corresponding to each solar cell submodule is offset from the second axis.   2. The solar cell module according to claim 1, wherein the shape of each cell is a sector having the same central angle with respect to the first axis.   The solar cell module according to claim 1 or 2, wherein the effective power generation area of each cell is the same.   4. The solar cell module according to claim 1, wherein the shape of the solar cell submodule is a fan shape having the same central angle with respect to the second axis. 5. The solar cell module, the solar cell module according to any of claims 1 4, characterized in that said circular around the central point of the solar cell submodule.   6. The solar cell module according to claim 1, wherein an inner partition that separates an electrolyte contained in each of the plurality of cells is formed thinner than an outer partition that separates the electrolyte and the outside. 6.   A plurality of solar cell submodules are connected in series by connecting a positive electrode terminal of the first solar cell submodule and a negative electrode terminal of a second solar cell submodule different from the first solar cell submodule. The solar cell module according to claim 1, wherein: When the width of the outer partition is W1, and the width of the inner partition is W2,
The solar cell module according to claim 6, wherein the first axis is set at a position offset by W1- (W2 / 2) with respect to the second axis.

Images