JP2005191479A - Solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell module that can be universally utilized using a back contact type solar cell and has an optimized interconnector shape. <P>SOLUTION: The electrodes of adjacent solar cells are connected by one tabular interconnector, thus simplifying connection work and also reducing loss in power generation. Additionally, the shape of the tabular interconnector is set to be a shape that does not cover the electrode on the solar cell as much as possible. More specifically, a connection point projects and the part between the electrode connection points of the same type on the same solar cell becomes a cutout, thus mixing a p-type electrode with an n-type one at the cutout and increasing generation efficiency. Additionally, width other than the connection point is allowed to become small, thus reducing the size of the material of the interconnector and consequently reducing costs. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solar cell module in which single crystal silicon solar cells having both P-type and N-type electrodes on the back surface are arranged side by side.

  Silicon solar cells generally have a single crystal silicon type, a polycrystalline silicon type, an amorphous silicon type, and the like, and the power generation efficiency is also in the above order.

  Amorphous silicon solar cells have advantages such as easy handling, shape and size can be changed relatively easily according to the application, and the appearance is good because there is no need to provide electrodes on the surface. However, the power generation efficiency is low, and generally crystalline silicon solar cells are widely used. In particular, single crystal silicon solar cells need to be handled with care, but have high power generation efficiency and are used in various applications.

  In a conventional single crystal solar cell, electrodes having different polarities, that is, a P-type electrode and an N-type electrode are provided on the front surface and the back surface, which are light receiving surfaces. In order to form a solar cell module using these solar cells, a plurality of solar cells must be arranged in parallel and connected in series. At that time, the electrode on the back surface of the cell adjacent to the surface electrode Need to be joined with an interconnector. FIG. 7 is a schematic view of a conventional solar cell, and FIG. 8 is a cross-sectional view showing an outline of the junction. The front surface electrode 23 and the back surface electrode 24 are provided on the entire front surface 21 and the back surface 22, respectively, and an interconnector is soldered to them. Since the electrodes are on the front and back surfaces, in order to attach the interconnector, it is necessary to solder one side at a time, and in the process of reversing the front and back of this soldering process, the cell is damaged and loss occurs. It often occurred. In addition, there are many parts to be soldered to the electrodes, and there has been a problem that the silicon single crystal is thermally expanded and contracted by heat at the time of soldering to cause cracking and warping. In addition, the front surface electrode 23 of the solar battery cell and the back surface electrode 24 of the adjacent solar battery cell are connected via the interconnector 4, and at this time, the interconnector needs to be circulated from the back surface to the front surface. There was a tendency for fatigue and disconnection due to thermal expansion and contraction of the entire solar cell module.

  In recent years, Patent Documents 1 to 4 have devised a method of manufacturing a solar cell in which both a P-type electrode and an N-type electrode are provided on the back surface. This solar cell is called a back contact type, and both the P-type electrode and the N-type electrode are provided on the back surface, and when connecting a plurality of solar cells, the back surface electrodes can be connected to each other. There are features. Therefore, there are no electrodes on the surface, the light receiving efficiency is improved and the appearance is also improved. In addition, since it is not necessary to wrap the interconnector from the electrode on the back surface to the electrode on the front surface, fatigue failure such as thermal expansion and contraction hardly occurs.

  A P-type electrode and an N-type electrode are formed on the back surface of the back contact type, but each electrode is formed in a comb shape, and the P-type electrode and the N-type electrode are alternately arranged between the combs. It is made to enter. As described above, the P-type electrodes and the N-type electrodes are alternately and densely provided, which facilitates the exchange of electrons, which is one factor for realizing high power generation efficiency. Therefore, increasing the area where the P-type electrode and the N-type electrode are mixed as much as possible is an element realizing high efficiency.

US Pat. No. 6,274,402 US Pat. No. 6,337,283 US Pat. No. 6,387,726 US Pat. No. 6,423,568

  However, although the back contact solar cell described above has been used alone or in units of a small number for some special purposes, it is not modularized for general power generation. Moreover, although the literature 1-4 mainly describes the manufacturing method of a photovoltaic cell, it does not mention until preparation of the specific module using it. The configuration of the back contact type solar cell is largely different from the conventional solar cell module in connecting the electrodes between a plurality of solar cells by the interconnector between the back surfaces. Little consideration has been given to electrode connection and interconnector shape in consideration of work efficiency during manufacturing.

  FIG. 9 shows a schematic diagram in which electrodes between conventional back contact solar cells are connected. The solar battery cell is provided with a plurality of connection points 163 between the P-type electrode and the interconnector along the side edge of one side of the back surface, and a plurality of connection points 164 between the N-type electrode and the interconnector on opposite sides. One is provided. The solar cells are arranged so that connection points of different electrodes are adjacent to each other, and the connection points are connected to each other by a ribbon-like interconnector 3 one by one.

  In this way, when the connection points are connected one by one with the ribbon-like interconnector, the labor of manufacturing becomes very large. Therefore, in the present invention, a solar battery module that can be used universally using the high-efficiency back-contact solar cell, and the interconnector can simplify the connection work between the solar cells. We intend to provide a solar cell module with an optimized shape.

  In order to achieve the above object, the present invention is configured as follows. That is, a plurality of solar cells are sealed with a sealing material and a protective member is provided on at least one surface thereof, and the solar cells have a P-type electrode and an N-type electrode on the back surface. A solar cell module in which a P-type electrode and an N-type electrode of adjacent solar cells are connected in series via an interconnector, the P-type electrode extending along a side edge of one side of the solar cell, A plurality of connection points for connecting the interconnector are provided, and a plurality of connection points for connecting the N-type electrode and the interconnector are provided along the side edges of the opposite sides. The cell is arranged so that the P-type electrode connection point and the N-type electrode connection point are adjacent to each other, and the plurality of P-type electrode connection points and N-type electrode connection point connection points of the adjacent solar cells are one sheet. Flat It is characterized in that it has been connected with the interconnector.

  By connecting multiple connection points arranged on the side edges of adjacent solar cells with a single flat interconnector, it is possible to eliminate the trouble of connecting each connection point separately and simplify the connection work. Become. When interconnector connection work is automated, the use of a single flat interconnector saves time and labor for setting the interconnector, as well as providing soldering positioning. It can be significantly shortened and the yield rate is improved.

  Further, by connecting with a single flat interconnector, the conductive area is widened, the electrical resistance is reduced, and the loss of power generation can be reduced. In addition, even if one of the connection points is not energized, it can be energized from another connection point, so that it is possible to prevent a decrease in power generation efficiency.

  The shape of the interconnector is not particularly limited, but naturally, care must be taken so that the P-type electrode and the N-type electrode on the same cell are not electrically joined. However, in order to improve the power generation efficiency, it is necessary to mix the P-type electrode and the N-type electrode in as wide an area as possible. Therefore, a portion other than the electrode junction should be cut out or an insulating material layer should be provided so that a short circuit does not occur on the cell.

  The interconnector has a flat plate shape capable of connecting a plurality of electrode connection points, and at least a part of the portion covering the solar cell electrode by the flat plate interconnector is cut out except for the electrode connection points. It is characterized by this.

  When connecting a plurality of connection points arranged on the sides of adjacent cells with a single flat interconnector, the flat interconnector has a shape that does not cover the electrodes on the solar cell as much as possible. Good. That is, it is good for the connection point part to have the shape which protruded, and to be a notch part between the same type electrode connection points on the same photovoltaic cell.

  Since the connection point portion protrudes as compared with other portions, it is easy to connect the interconnector and the electrode. Further, since the portion other than the connection point is cut out so as not to cover the electrode on the solar cell as much as possible, a P-type electrode and an N-type electrode are also mixed in the cut-out portion. The front surface contributes to power generation, and the power generation efficiency can be increased. Further, by reducing the width of the portion other than the connection point, the material of the interconnector can be reduced, leading to cost reduction.

  According to the present invention, by connecting the electrodes of the adjacent solar battery cells with one flat interconnector, the connection work is simplified, the work time can be greatly shortened, and the yield rate is improved.

  Further, by connecting with a single flat interconnector, the conductive area is widened, so that the electrical resistance is reduced and the loss of power generation can be reduced. In addition, even if one of the connection points is not energized, it can be energized from another connection point, so that a reduction in power generation efficiency can be prevented.

In addition, the shape of the flat interconnector should be such that the electrodes on the solar cells are not covered as much as possible, that is, the connection point portion protrudes and between the same-type electrode connection points on the same solar cell. By being a notch portion, the P-type electrode and the N-type electrode can be mixed in the notch portion, and the power generation efficiency can be increased. Further, by reducing the width of the portion other than the connection point, the material of the interconnector can be reduced, leading to cost reduction.

  Embodiments according to the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an example of a solar battery cell used in the present invention. FIG. 1a is an explanatory view of a solar battery cell, and the A surface shows a cross section. FIG. 1 b is an explanatory plan view showing the state of the electrode on the back surface of the solar battery cell. Similarly, FIG. 7 shows an explanatory view showing an example of a conventional single crystal silicon solar cell. As shown in FIG. 7, the conventional solar cell has electrodes of different polarities formed on the front surface and the back surface, but the solar cell used in the present invention is a solar cell 1 as shown in FIGS. The front surface 11 has no electrode, and the back surface 12 is provided with a P-type electrode 13 and an N-type electrode 14. The P-type electrode and the N-type electrode on the back surface are each formed in a comb shape, and each alternately enter between the combs.

  FIG. 2 is a schematic view showing an example of a method for joining electrodes of adjacent solar battery cells in the solar battery module of the present invention, and shows a cross section of the solar battery module. Similarly, FIG. 8 shows an example of an electrode bonding method when a conventional single crystal silicon solar cell is used.

  When the conventional solar battery cell 2 is connected by the interconnector 4, as shown in FIG. 8, it must be connected so as to wrap around one surface electrode 23 and the back electrode 24 of the other cell. It must wrap around through the cell-to-cell spacing 25. At this time, there was a tendency that the wraparound part f was easily fatigued and disconnected due to thermal expansion and contraction of the entire solar cell module. Moreover, since it is necessary to wrap around, the width | variety of the separation part 25 becomes large inevitably.

  As shown in FIG. 2, the back-contact type solar battery cell only needs to connect the P-type electrode 13 and the N-type electrode 14 on the back surface of the adjacent solar battery cell, so that the interconnector is also short and needs to go around. Since there is no, the separation part 15 can also be made small. Moreover, since the influence of thermal expansion and contraction is reduced, the possibility of breakage is small.

  FIG. 3 is a schematic diagram illustrating an example of a solar cell module using back contact solar cells, and FIG. 4 is an explanatory diagram illustrating a cross section of the example of the implementation.

  A back contact type solar cell 1 having both P-type and N-type electrodes on the back surface is sealed with a sealing material 51, a glass plate of a protective member 52 is attached to the front surface side, and protection is provided on the back side. A resin film is attached as the member 53 to form a laminate. An aluminum frame 54 is attached around the periphery.

  Adhesive synthetic resin is suitably used as the sealing material for sealing the solar cells, and has translucency such as ethylene-vinyl acetate (EVA), transparent modified polyethylene, modified polypropylene, acrylic resin, silicon resin, etc. Can be used, and EVA is preferably used.

  The protective member 52 provided on the surface side is preferably glass in view of light transmittance and thermal expansion coefficient, but is not limited to this, and sunlight is transmitted to protect the solar battery cell from external force. It may be a member that can be used, and may be a synthetic resin plate or a film made of synthetic resin. If a resin plate or film is used, the module can be reduced in weight. As long as it is a synthetic resin plate or film, for example, a polycarbonate resin, an acrylic resin, a vinyl chloride resin, a PET resin, or a PVF resin may be used.

  Further, the protective member 53 provided on the back side is preferably a synthetic resin film in consideration of handleability and lightness, but is not limited to this as long as it can prevent moisture and foreign matter from entering. A glass plate, a synthetic resin plate, a metal plate, a composite plate of resin and metal, or the like can also be used.

  Next, FIG. 5 and FIG. 6 show an example of an interconnector that connects electrodes of adjacent solar cells. On the opposite sides of the adjacent solar cells, a P-type electrode 13 is provided on one cell, and an N-type electrode 14 is provided on the other. The connection point 16 with the interconnector has three points at both ends and the center. It is provided one by one. One flat interconnector 3 is attached so as to cover these connection points. In this interconnector, the vicinity of the connection point 16 with the electrode is wide and the vicinity of the connection point protrudes. The interconnector is notched and narrowed at a point 17 between the connection points of the same-type electrode, and in FIG. 7, the width gradually decreases in a curve as the distance from the connection point increases. In FIG. 6, the V-hour type is cut out and the portion without the connection point is constricted.

  As a result, the connection work between the interconnector and the electrode is easy to perform, and the width gradually decreases as the distance from the connection point increases. Even if this occurs, there is no risk of disconnection from the interconnector. Further, by reducing the width of the portion other than the connection point, the material of the interconnector can be reduced, leading to cost reduction.

  In addition, by making the constriction in this way, the other electrode can enter the constricted portion 17. Thereby, since the P-type electrode and the N-type electrode are evenly distributed in a wide range, the power generation efficiency can be improved, which is preferable.

  Further, the interconnector 3 may have a buffer structure in which a flat plate is bent, and in this way, it can follow an external force such as thermal expansion, thereby improving durability. Can prevent disconnection due to fatigue.

  The material of these interconnectors is not particularly limited as long as it has high conductivity, but Cu, Ag, Au, Pt, Sn, an alloy containing these, or the like can be used. Further, a composite material of a resin material and a metal may be used. As the composite material of the resin material and the metal, for example, a material in which a metal plate is bonded to a resin sheet, a material in which a metal foil is attached on the resin sheet, or a material in which a metal is deposited can be used. Moreover, the interconnector may not be a plate shape but may be a solid shape containing the metal.

  Further, the interconnector may be formed by using a mesh material. By using a mesh material, the material cost can be reduced and the interconnector can be stretched, and the expansion and contraction of the interconnector due to the thermal expansion and contraction of the solar cell module can be absorbed, and fatigue failure can be prevented. it can.

It is the schematic which shows one form of the photovoltaic cell used for the solar cell module of this invention. It is a schematic diagram of the cross section which shows an example of the connection of the photovoltaic cell of this invention. It is the conceptual diagram which showed an example of the whole image of the solar cell module of this invention. It is the conceptual diagram which showed a part of cross section of the solar cell module of this invention. It is the schematic diagram which showed an example of implementation of the interconnector which connects the photovoltaic cells of this invention. It is the schematic diagram which showed an example of implementation of the interconnector which connects the photovoltaic cells of this invention. It is the schematic which shows an example of the conventional photovoltaic cell. It is a schematic diagram which shows an example of the connection of the conventional photovoltaic cell. It is a schematic diagram which shows an example of the connection of the conventional photovoltaic cell.

Explanation of symbols

A Cross section of solar cell f Interconnector wrap
DESCRIPTION OF SYMBOLS 1 Solar cell 11 Surface of solar cell 12 Back surface of solar cell 13 P-type electrode 14 N-type electrode 15 Separation part 16 Connection point of electrode and interconnector 163 Connection point of electrode and interconnector 164 Electrode and interconnector 17 Constriction part 2 Conventional solar cell 21 Surface of solar cell 22 Back surface of solar cell 23 Surface electrode 24 Back surface electrode 25 Spacing part 3 Interconnector 5 Solar cell module 51 Sealing material 52 On the surface side Protective member 53 Back side protective member 54 Aluminum frame

Claims (2)

A plurality of solar cells are sealed with a sealing material, and at least one surface thereof is provided with a protective member, and the solar cells have a P-type electrode and an N-type electrode on the back surface. A solar cell module in which P-type electrodes and N-type electrodes of adjacent solar cells are connected in series via an interconnector, and the P-type electrode and the inter-electrode are connected along the side edge of one side of the solar cells. A plurality of connection points for connecting the connector are provided, and a plurality of connection points for connecting the N-type electrode and the interconnector are provided along the side edges of the side opposite to the side. Is arranged so that the P-type electrode connection point and the N-type electrode connection point are adjacent to each other, and the plurality of P-type electrode connection points and the N-type electrode connection point connection points of the adjacent solar cells are one flat plate. Interchange Solar cell module characterized in that it is connected with the connector. The interconnector has a flat plate shape capable of connecting a plurality of electrode connection points, and at least a part of the portion covering the solar cell electrode by the flat plate interconnector is cut out except for the electrode connection points. The solar cell module according to claim 1.

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