JP2009295940A - Solar battery cell and solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a solar battery cell having excellent bonding strength between the solar battery cell and a lead wire, and high durability and reliability when forming a solar battery module by electrically connecting a plurality of solar battery cells by bonding a lead wire to the solar battery cells with a conductive bonding agent, and the solar battery module configured by connecting a plurality of the solar battery cells. <P>SOLUTION: The solar battery cell has a lead connection electrode for electrically connecting a lead wire by a conductive adhesive to a light-receiving face and its rear face. The lead connection electrode includes a plurality of projections on the face to which the lead wire is connected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solar battery cell and a solar battery module formed by connecting a plurality of the solar battery cells.

  A solar cell is configured by electrically connecting a plurality of solar cells in order to obtain a predetermined voltage and current. As a method of electrically connecting a plurality of solar cells, a copper wire covered with solder is soldered to the front electrode formed on the light receiving surface side of the solar cell and the back electrode formed on the side opposite to the light receiving surface. The method of attaching is common.

  However, since there is a difference in thermal expansion coefficient between the lead wire and the solar battery cell, residual stress is generated in the solar battery cell after joining the lead wire due to heating during soldering. And there exists a problem that it will lead to the deterioration of the productivity in a manufacturing process, a yield, and the reliability of a solar cell because curvature or a micro crack will arise in this photovoltaic cell by this residual stress. This problem becomes more prominent as the solar cell becomes thinner.

  For this reason, a method of using a conductive adhesive instead of soldering has been studied with respect to the above problem when soldering a lead wire to a solar battery cell. For example, in Patent Document 1, in a flexible thin-film solar battery module in which a photoelectric conversion layer made of a thin film such as amorphous silicon is formed on a plastic substrate, an electrode of a solar battery cell and a lead wire are connected by a conductive adhesive, A method is disclosed in which the conductive adhesive is cured in the same heating process as that of sealing with a binder resin, so that the plastic substrate is not deformed, discolored, or changed in characteristics by heating during soldering.

  Further, in Patent Document 2, a plurality of solar cells not having a bus bar electrode and a lead wire are connected using a thermosetting conductive adhesive, thereby omitting a lead wire soldering step. There is disclosed a method aiming to improve productivity, yield and long-term reliability without cell warpage.

JP-A-8-213643 JP 2005-243935 A

  However, the method of using a conductive adhesive for connecting the solar cell and the lead wire as in the above-mentioned conventional technology reduces the residual stress to the solar cell after the lead wire bonding by lowering the heating temperature. However, there is a problem that the adhesive strength between the solar battery cell and the conductive adhesive and the adhesive strength between the lead wire and the conductive adhesive are low, and the lead wire is peeled off.

  This invention is made | formed in view of the above, Comprising: When forming a solar cell module by electrically connecting a plurality of solar cells by bonding a lead wire to the solar cells with a conductive adhesive An object of the present invention is to obtain a solar cell having excellent adhesion strength between the solar cell and the lead wire and having high durability and reliability, and a solar cell module formed by connecting a plurality of the solar cells.

  In order to solve the above-described problems and achieve the object, a solar battery cell according to the present invention has a lead connection electrode for electrically connecting a lead wire with a conductive adhesive on the light receiving surface and the back surface thereof. It is a photovoltaic cell, The lead connection electrode is provided with a some protrusion part in the surface which connects the said lead wire, It is characterized by the above-mentioned.

  According to this invention, the anchoring effect (throwing effect) of the conductive adhesive to the solar battery cell when the lead connecting electrode and the lead wire are electrically connected by the conductive adhesive is provided by the protrusions of the lead connecting electrode. The connection strength between the solar battery cell and the lead wire can be improved by increasing the bonding area. Thereby, it is excellent in the adhesive strength of a photovoltaic cell and a lead wire, and there exists an effect that a durable and reliable photovoltaic cell can be obtained.

  Hereinafter, embodiments of a solar battery cell and a solar battery module according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1 FIG.
1 and 2 are diagrams showing a schematic configuration of the solar battery cell 10 according to the first embodiment of the present invention. FIG. 1 is a plan view of the light receiving surface side of the solar battery cell 10, and FIG. It is sectional drawing in line segment AA. In solar cell 10 according to the first embodiment, for example, an impurity diffusion layer is formed by phosphorus diffusion on the light-receiving surface side of a p-type polycrystalline silicon substrate that is semiconductor substrate 1, and an antireflection film made of a silicon nitride film Is formed. Since the impurity diffusion layer and the antireflection film are not directly related to the present invention, the illustration and detailed description thereof are omitted.

  On the light receiving surface side of the solar cell 10, the cell light receiving surface grid electrode 2, which is a plurality of thin wire electrodes, for collecting current from the entire surface of the solar cell 10 and improving the conversion efficiency while ensuring a wide light receiving area as much as possible. However, as shown in FIG. 1, it is arrange | positioned substantially parallel over the full width of the width direction of the photovoltaic cell 10. As shown in FIG.

  Further, on the light receiving surface side of the solar battery cell 10, two lead connection electrodes 3 that are electrically connected to the cell light receiving surface grid electrode 2 are provided as lead connection electrodes in the in-plane direction of the light receiving surface as shown in FIG. 1. The solar cell 10 is provided over almost the entire length in the length direction so as to be substantially orthogonal to the light receiving surface grid electrode 2. Here, the longitudinal direction of the cell light receiving surface grid electrode 2 is the width direction of the solar battery cell 10, and the longitudinal direction of the lead connection electrode 3 is the longitudinal direction of the solar battery cell 10.

  In the present embodiment, the number of lead connection electrodes 3 is two, but the number of lead connection electrodes 3 may be three or more. The lead wire 5 is electrically connected (joined) to the lead connection electrode 3 by the conductive adhesive 4 in a later step of manufacturing the solar cell described later.

  The surface (upper surface) 3 b on the side connected to the lead wire 5 in the lead connection electrode 3 is a direction (substantially orthogonal to the longitudinal direction of the lead connection electrode 3 in order to improve the adhesive force with the conductive adhesive 4 ( A pattern of a plurality of thin protrusions (projections) 3 a extending in the direction substantially parallel to the longitudinal direction of the cell light receiving surface grid electrode 2 is formed.

  Further, a back electrode (not shown) and a lead connection electrode 13 for connecting the lead wire 5 are formed on the side opposite to the light receiving surface of the solar battery cell 10. Further, the adhesion force with the conductive adhesive 4 is also improved on the surface (upper surface) 13b of the lead connection electrode 13 on the side opposite to the light receiving surface, which is connected to the lead wire 5, similarly to the lead connection electrode 3 on the light receiving surface side. In order to achieve this, a plurality of thin convex portions 13a are formed.

  The dimensions of the protrusion 3a and the protrusion 13a are preferably such that the height from the upper surface 3b of the lead connection electrode 3 or the upper surface 13b of the lead connection electrode 13 is 10 μm to 100 μm and the width is 10 μm to 5 mm. Such protrusions 3 a and protrusions 13 a may be arranged at equal intervals in the longitudinal direction of the lead connection electrode 3 or the lead connection electrode 13, and the residual stress of the solar battery cell 10 after the connection of the lead wire 5 is reduced. In order to relax, the lead connection electrodes 3 or the lead connection electrodes 13 may be arranged at unequal intervals, for example, the pitch is narrowed toward the outside in the longitudinal direction.

  FIG. 3 is a cross-sectional view of a main part of a solar cell module configured by connecting a plurality of the solar cells 10 shown in FIGS. 1 and 2, and lead connection of the solar cells 10 using the conductive adhesive 4. FIG. 4 is a cross-sectional view of a main part showing a state in which a lead wire 5 is connected to an electrode 3 and a lead connection electrode 13. FIG. 3 corresponds to a cross-sectional view taken along line AA in FIG. Further, illustration of a sealing material such as glass or a resin sheet is omitted.

  The conductive adhesive 4 is an adhesive that develops conductivity by mixing a conductive filler with a thermosetting resin adhesive. As the adhesive, an epoxy resin, an acrylic resin, or the like is used, and a curing temperature of 200 ° C. or lower is preferable. As the conductive filler, silver (Ag) particles having good conductivity are often used, but copper (Cu) particles, nickel (Ni) plating resin particles, and the like can also be used. Various shapes of conductive fillers can be used.

  By connecting the lead wire 5 with the conductive adhesive 4 to the lead connection electrode 3 having the convex portion 3a, the convex portion 3a of the lead connection electrode 3 bites into the conductive adhesive 4 as shown in FIG. Therefore, the anchor effect (throwing effect) of the conductive adhesive 4 is enhanced, and the adhesive area between the lead connection electrode 3 and the conductive adhesive 4 is increased due to the presence of the convex portion 3a. The adhesive strength with the lead connection electrode 3 is improved. Thereby, the adhesive strength between the lead connection electrode 3 and the lead wire 5 can be improved. Further, as an effect of increasing the bonding area between the lead connection electrode 3 and the conductive adhesive 4, in addition to improving the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3, the space between the solar battery cell 10 and the lead wire 5 is increased. Resistance can be reduced and characteristics can be improved.

  Similarly, the lead wire 5 is connected to the lead connection electrode 13 having the convex portion 13a by using the conductive adhesive 4, so that the convex portion 13a of the lead connection electrode 13 is connected to the conductive adhesive 4 as shown in FIG. As a result, the anchor effect (throwing effect) of the conductive adhesive 4 is enhanced, and the adhesive area between the lead connection electrode 13 and the conductive adhesive 4 is increased due to the presence of the convex portion 13a. 4 and the lead connection electrode 13 are improved in adhesive strength. Thereby, the adhesive strength between the lead connection electrode 13 and the lead wire 5 can be improved. Further, as an effect of increasing the bonding area between the lead connection electrode 13 and the conductive adhesive 4, in addition to improving the adhesive strength between the conductive adhesive 4 and the lead connection electrode 13, the space between the solar battery cell 10 and the lead wire 5 is increased. Resistance can be reduced and characteristics can be improved.

  Further, as shown in FIG. 4, by forming a protrusion on the surface of the lead wire 5 and providing the uneven shape 5 a, the anchor effect of the conductive adhesive 4 and the adhesion between the lead wire 5 and the conductive adhesive 4 are achieved. By increasing the area, the adhesive strength between the conductive adhesive 4 and the lead wire 5 can be improved on both the light receiving surface side and the non-light receiving surface side. FIG. 4 is a cross-sectional view of a main part of the solar cell module when the uneven shape 5a is provided on the surface of the lead wire 5. As shown in FIG.

  The solar battery cell 10 according to the first embodiment configured as described above is manufactured as follows. First, as the semiconductor substrate 1, for example, a p-type polycrystalline silicon substrate in which an impurity diffusion layer is formed by phosphorous diffusion on the surface on one surface side of the substrate is prepared. A silicon nitride film is formed as an antireflection film on the semiconductor substrate 1 by, for example, a plasma enhanced chemical vapor deposition (PECVD) method.

  Next, after applying silver conductive paste to the shape of the cell connection surface grid electrode 2 and the lead connection electrode 3 without the protrusion 3a by screen printing on the light receiving surface side of the semiconductor substrate 1, the conductive paste is temporarily dried. . Thereafter, the second pattern of screen printing is similarly performed using the mask pattern in which the convex portion 3a is opened, so that the convex shape is formed on the silver conductive paste of the lead connection electrode 3 formed by the first printing. A silver conductive paste is applied to the shape of the portion 3a and temporarily dried. Thereby, the shape of the convex portion 3 a is formed on the substantially flat lead connection electrode 3.

  Next, an aluminum paste is applied in the shape of the back electrode on the side opposite to the light receiving surface of the semiconductor substrate 1, a silver conductive paste is applied in the shape of the lead connection electrode 13, and then temporarily dried. After that, the second pattern of screen printing is similarly performed using the mask pattern in which the portion of the convex portion 13a is opened, so that the convex portion is formed on the silver conductive paste of the lead connection electrode 13 formed by the first printing. By applying a silver conductive paste to the shape of the portion 13a, drying, and baking the paste, the cell light receiving surface grid electrode 2, the lead connection electrode 3, the back electrode, and the lead connection electrode 13 are formed. Thus, the solar battery cell 10 according to the first embodiment is obtained.

  In addition, the paste used for forming the electrode of the solar battery cell 10 may use a gold paste or other conductive paste in addition to the silver paste. Moreover, it is also possible to form the electrode of the solar battery cell 10 by plating, an inkjet printing method, or the like.

  Next, a method for connecting the solar battery cell 10 and the lead wire 5 using the conductive adhesive 4 will be described. As one method, after applying the conductive adhesive 4 on the lead connection electrode 3 of the solar battery cell 10, the lead wire 5 is disposed on the conductive adhesive 4, and the conductive adhesive 4 is heated and cured. There is. The same applies to the lead connection electrode 13. As another method, there is a method in which after the conductive adhesive 4 is applied to the lead wire 5, the lead wire 5 is disposed on the lead connection electrode 3 and the conductive adhesive 4 is heated and cured. The same applies to the lead connection electrode 13. These methods are appropriately selected according to various conditions such as the characteristics of the conductive adhesive 4 and the design of the manufacturing process.

  And a solar cell module can be produced by connecting a plurality of solar cells 10 to which the lead wires 5 are connected by the above method, and sealing with a sealing material such as glass or a resin sheet. Thereby, the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3 is improved by the convex portion 3 a formed on the lead connection electrode 3, and the convex portion 13 a formed on the lead connection electrode 13 is improved. The adhesive strength between the conductive adhesive 4 and the lead connection electrode 13 is improved, and a solar cell module excellent in characteristics and long-term reliability can be obtained.

  As described above, according to the solar cell according to the first embodiment, the conductive adhesive 4 with respect to the solar cell 10 is formed by the convex portion 3a of the lead connection electrode 3 and the convex portion 13a of the lead connection electrode 13. Anchor effect (throwing effect) is increased. Moreover, the conductive adhesive is obtained by increasing the adhesion area between the lead connection electrode 3 and the conductive adhesive 4 and the adhesion area between the lead connection electrode 13 and the conductive adhesive 4 due to the convex portions 3a and the convex portions 13a. 4 and the lead connection electrode 3 and the adhesive strength between the conductive adhesive 4 and the lead connection electrode 13 are improved. Therefore, in the solar cell according to the first embodiment, when the plurality of solar cells 10 are electrically connected by the conductive adhesive 4 and the lead wire 5 to form the solar cell module, the lead connection electrode 3 and the lead wire 5 and the adhesive strength between the lead connection electrode 13 and the lead wire 5 can be improved, and the adhesive strength between the solar battery cell 10 and the lead wire 5 can be improved.

  Further, as an effect of increasing the adhesive area, in addition to improving the adhesive strength, the resistance between the solar battery cell 10 and the lead wire 5 can be reduced to improve the characteristics.

  Moreover, according to the solar cell module concerning this Embodiment, since the photovoltaic cell 10 concerning Embodiment 1 mentioned above is electrically connected by the conductive adhesive 4 and the lead wire 5, it is comprised. Thus, a solar cell module excellent in characteristics and long-term reliability is realized.

  According to the solar cell module according to the present embodiment, since the lead connection electrode 3 and the lead wire 5 are joined not by soldering but by the conductive adhesive 4, the solar cell resulting from heating during soldering. There is no generation of residual stress. As a result, a solar cell module in which the solar cell is not warped or microcracked due to the residual stress and the productivity and yield in the manufacturing process are prevented from deteriorating is realized.

Embodiment 2. FIG.
In the first embodiment, the case where the surface of the lead connection electrode 3 is provided with a pattern of a plurality of thin protrusions 3a extending in a direction substantially parallel to the longitudinal direction of the cell light receiving surface grid electrode 2 has been described. In the second embodiment, another pattern of the convex portion 3a will be described.

  FIG. 5 is a diagram showing a schematic configuration of the solar battery cell according to the second embodiment, and is a plan view on the light receiving surface side. The solar cell according to the second embodiment has the same configuration as that of the solar cell according to the first embodiment except for the pattern of the convex portions 3 a provided on the surface of the lead connection electrode 3.

  In the solar cell according to the second embodiment, as shown in FIG. 5, the surface (upper surface) 3b on the side connected to the lead wire 5 in the lead connection electrode 3 is larger than 0 ° with the cell light receiving surface grid electrode 2, A pattern of convex portions 3 c provided in a “square shape” or a “reverse shape” at a predetermined angle smaller than 90 ° is arranged in the longitudinal direction of the lead connection electrode 3. As for the dimension of the convex part 3c, it is preferable that the height from the upper surface 3b of the lead connection electrode 3 is 10 μm to 100 μm. Such protrusions 3 c may be arranged at equal intervals in the longitudinal direction of the lead connection electrode 3, and in order to relieve the residual stress of the solar battery cell 10 after the connection of the lead wire 5, They may be arranged at unequal intervals, for example, the pitch is narrower toward the outside in the longitudinal direction.

  When the conductive adhesive 4 is cured to join the lead wire 5 to the lead connection electrode 3, the conductive adhesive 4 contracts. Here, by providing an angle to the convex portion 3c, the conductive adhesive 4 bites into the convex portion 3c like a wedge, and the length of the convex portion 3c is increased to increase the surface area of the convex portion 3c. Thus, the adhesion area between the lead connection electrode 3 and the conductive adhesive 4 is increased, and the adhesion strength between the conductive adhesive 4 and the lead connection electrode 3 is improved. Thereby, the adhesive strength between the lead connection electrode 3 and the lead wire 5 can be improved. Further, as an effect of increasing the bonding area between the lead connection electrode 3 and the conductive adhesive 4, in addition to improving the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3, the space between the solar battery cell 10 and the lead wire 5 is increased. Resistance can also be reduced. Furthermore, by releasing the contraction in the longitudinal direction of the conductive adhesive 4 in the short direction, the residual stress can be relaxed and the adhesion reliability can be further increased.

  As another example of the convex portion that can obtain the same effect as the convex portion 3c shown in FIG. 5, for example, the convex portion 3d of the lead connection electrode 3 as shown in FIG. 6, the convex portion of the lead connection electrode as shown in FIG. The pattern of the part 3e can also be used. FIG. 6 is a plan view of the light receiving surface side of the solar battery cell 10 having a convex portion 3d as another example of the convex portion on the surface (upper surface) 3b on the side connected to the lead wire 5 in the lead connection electrode 3. is there. FIG. 7 is a plan view of the light receiving surface side of the solar battery cell 10 having a convex portion 3e as another example of the convex portion on the surface (upper surface) 3b on the side connected to the lead wire 5 in the lead connection electrode 3. is there.

  In the solar battery cell 10 shown in FIG. 6, a “U-shaped” or “reverse U-shaped” formed by combining the pattern of the convex portion 3 a shown in FIG. 1 and the pattern of the convex portion 3 c shown in FIG. 5. A pattern of the convex portion 3 d having a shape is provided on the surface (upper surface) 3 b of the lead connection electrode 3 on the side connected to the lead wire 5. Further, in the solar battery cell 10 shown in FIG. 7, the pattern of the convex portion 3 e having a substantially semicircular ring shape having a curved portion in the longitudinal direction of the lead connection electrode 3 is connected to the lead wire 5 in the lead connection electrode 3. Is provided on the surface (upper surface) 3b.

  Providing such a pattern of the convex portion 3d or the pattern of the convex portion 3e on the surface (upper surface) 3b of the lead connection electrode 3 on the side connected to the lead wire 5 also provides the same effect as the convex portion 3c. . That is, when the conductive adhesive 4 is cured to join the lead wire 5 to the lead connection electrode 3, the conductive adhesive 4 bites into the convex portion 3d or the convex portion 3e like a wedge, and the convex portion 3d. Or the surface area of the convex part 3e becomes large, the adhesion area of the lead connection electrode 3 and the conductive adhesive 4 increases, and the adhesive strength of the conductive adhesive 4 and the lead connection electrode 3 improves. Further, as an effect of increasing the bonding area between the lead connection electrode 3 and the conductive adhesive 4, in addition to improving the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3, the space between the solar battery cell 10 and the lead wire 5 is increased. Resistance can also be reduced. Furthermore, by releasing the contraction in the longitudinal direction of the conductive adhesive 4 in the short direction, the residual stress can be relaxed and the adhesion reliability can be further increased.

  In addition, as shown in FIG. 8, the pattern of the convex portions 3 c provided in the “square shape” or “inverted square shape” may be formed in two rows in the longitudinal direction of the lead connection electrode 3. it can. FIG. 8 shows a solar cell having convex portions 3 c formed in a pattern extending in two rows in the longitudinal direction of the lead connection electrode 3 on the surface (upper surface) 3 b on the side connected to the lead wire 5 in the lead connection electrode 3. 2 is a plan view of a light receiving surface side of a battery cell 10. FIG.

  By providing such a pattern of two rows of convex portions 3c on the surface (upper surface) 3b of the lead connection electrode 3 on the side connected to the lead wire 5, the same as when the convex portions 3c are formed in one row. An effect is obtained. That is, when the conductive adhesive 4 is cured to join the lead wire 5 to the lead connection electrode 3, the conductive adhesive 4 bites into the two rows of convex portions 3c like a wedge, and the convex portions 3c By increasing the surface area, the adhesion area between the lead connection electrode 3 and the conductive adhesive 4 is increased, and the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3 is improved.

  Furthermore, by forming the pattern of the convex portions 3c in two rows, even when the application position of the conductive adhesive 4 or the position of the lead wire 5 is shifted in the short direction of the lead connection electrode 3, it is difficult to cure. When shrinking, the conductive adhesive 4 bites into the pattern of the convex portions 3 c formed in two rows on the lead connection electrode 3 like a wedge, and increases the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3. effective.

  FIG. 8 shows a case where the patterns of the convex portions 3 c provided in the “R” shape or the “R” shape are formed in two rows in the longitudinal direction of the lead connection electrode 3. As shown, the pattern of the protrusions 3 d may be formed in two rows in the longitudinal direction of the lead connection electrode 3. Further, as shown in FIG. 10, the pattern of the protrusions 3 e may be formed in two rows in the longitudinal direction of the lead connection electrode 3. Also in these cases, the same effect as the case where the patterns of the convex portions 3 c are formed in two rows in the longitudinal direction of the lead connection electrode 3 as shown in FIG. 8 can be obtained. Further, the number of rows of patterns such as the convex portions 3c is not limited to two, and may be three or more.

  In addition, as shown in FIG. 11, the convex portion 3 c increases from the center to the end portion in the longitudinal direction of the lead connection electrode 3 on the surface (upper surface) 3 b on the side connected to the lead wire 5 in the lead connection electrode 3. The angle formed with the cell light receiving surface grid electrode 2 may be increased. In other words, the angle of the “shape” becomes steeper as it goes in the end direction in the longitudinal direction of the lead connection electrode 3, and the angle of the “shape” becomes shallower toward the center in the longitudinal direction of the lead connection electrode 3. It is also good.

  When the conductive adhesive 4 is cured in order to join the lead wire 5 to the lead connection electrode 3, the conductive adhesive 4 contracts. However, the distance from the center in the longitudinal direction of the lead connection electrode 3 moves due to the contraction. The amount increases. The central portion in the longitudinal direction does not contract in the longitudinal direction, but only contraction in the short direction occurs. Further, since the end portion in the longitudinal direction has a larger contraction in the longitudinal direction than the contraction in the short direction, the angle of the “shape” is made steep. By adopting such a configuration, when the conductive adhesive 4 contracts, it becomes easy to bite into the pattern of the convex portions 3c provided on the lead connection electrode 3 like a wedge, and the conductive adhesive 4 and the lead connection electrode The adhesive strength with 3 can be increased.

  In the above description, the pattern of the convex portion 3c has been described as an example. However, the pattern of the convex portion 3d and the pattern of the convex portion 3e also have a cell light receiving surface grid electrode 2 as the distance from the center in the longitudinal direction of the lead connection electrode 3 increases. It is good also as a structure with which the angle made between becomes large. Furthermore, as shown in FIGS. 8 to 10, the present invention may be applied when the convex portions 3 c, the convex portions 3 d, and the convex portions 3 e are arranged in a plurality of rows.

Embodiment 3 FIG.
12 and 13 are plan views of relevant parts on the light receiving surface side of the solar battery cell according to the third embodiment, and are diagrams showing still another pattern of the convex part 3a. FIG. 12 shows a state in which fine convex portions 3f having a substantially cylindrical shape are arranged in a predetermined arrangement pattern on the surface (upper surface) 3b on the side connected to the lead wire 5 in the lead connection electrode 3. FIG. 13 shows a state in which fine protrusions 3g having a substantially rectangular parallelepiped shape are arranged in a predetermined arrangement pattern on the surface (upper surface) 3b on the side connected to the lead wire 5 in the lead connection electrode 3.

  By connecting the lead wire 5 using the conductive adhesive 4 to the lead connection electrode 3 having the convex portion 3f or the convex portion 3g, the lead is connected to the conductive adhesive 4 as in the case of the convex portion 3a. Since the protrusion 3f or the protrusion 3g of the connection electrode 3 bites in, the anchor effect (throwing effect) of the conductive adhesive 4 is enhanced, and the presence of the protrusion 3f or the protrusion 3g leads to the lead connection electrode 3 and the conductive adhesive. By increasing the adhesion area with the conductive adhesive 4, the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3 is improved. Thereby, the adhesive strength of the lead connection electrode 3 and the lead wire 5 can be improved similarly to the case of the convex part 3a. Further, as an effect of increasing the bonding area between the lead connection electrode 3 and the conductive adhesive 4, in addition to improving the adhesive strength between the conductive adhesive 4 and the lead connection electrode 3, the space between the solar battery cell 10 and the lead wire 5 is increased. Resistance can be reduced and characteristics can be improved.

  In the above description, the light receiving surface side is described. However, the same effect can be obtained when the light receiving surface side is applied.

  As described above, according to the solar battery cell according to the second embodiment, the anchor effect (throwing effect) of the conductive adhesive 4 on the solar battery cell 10 by the convex portions 3c, 3d, and 3e of the lead connection electrode 3. Will increase. Further, the adhesion area between the conductive adhesive 4 and the lead connection electrode 3 is improved by increasing the adhesion area between the lead connection electrode 3 and the conductive adhesive 4 due to the convex portions 3 c, 3 d, and 3 e.

  Therefore, in the solar cell according to the second embodiment, as in the case of the first embodiment, a plurality of solar cells 10 are electrically connected by the conductive adhesive 4 and the lead wire 5 to form a solar cell. When forming a module, the adhesive strength between the lead connection electrode 3 and the lead wire 5 can be improved, and the adhesive strength between the solar battery cell 10 and the lead wire 5 can be improved.

  Further, as an effect of increasing the adhesive area, in addition to improving the adhesive strength, the resistance between the solar battery cell 10 and the lead wire 5 can be reduced to improve the characteristics. Furthermore, by releasing the contraction in the longitudinal direction of the conductive adhesive 4 in the short direction, the residual stress can be relaxed and the adhesion reliability can be further increased.

  As described above, the solar battery cell according to the present invention is useful when a solar battery module is manufactured by electrically connecting a plurality of solar battery cells with a conductive adhesive and a lead wire.

It is a top view by the side of the light-receiving surface of the photovoltaic cell concerning Embodiment 1 of this invention. It is sectional drawing in line segment AA of FIG. It is principal part sectional drawing of the solar cell module comprised by connecting two or more photovoltaic cells concerning Embodiment 1 of this invention. It is principal part sectional drawing of a solar cell module at the time of providing uneven | corrugated shape in the surface of a lead wire. It is a top view by the side of the light-receiving surface of the photovoltaic cell concerning Embodiment 2 of this invention. It is a top view by the side of the light-receiving surface of the other photovoltaic cell concerning Embodiment 2 of this invention. It is a top view by the side of the light-receiving surface of the other photovoltaic cell concerning Embodiment 2 of this invention. It is a top view by the side of the light-receiving surface of the other photovoltaic cell concerning Embodiment 2 of this invention. It is a top view by the side of the light-receiving surface of the other photovoltaic cell concerning Embodiment 2 of this invention. It is a top view by the side of the light-receiving surface of the other photovoltaic cell concerning Embodiment 2 of this invention. It is a top view by the side of the light-receiving surface of the other photovoltaic cell concerning Embodiment 2 of this invention. It is a principal part top view by the side of the light-receiving surface of the photovoltaic cell concerning Embodiment 3 of this invention. It is a principal part top view by the side of the light-receiving surface of the photovoltaic cell concerning Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Cell light-receiving surface grid electrode 3 Lead connection electrode 3a Convex part 3b The surface (upper surface) of the side connected with the lead wire in the light receiving surface side lead connection electrode
3c Convex part 3d Convex part 3e Convex part 3f Convex part 3g Convex part 4 Conductive adhesive 5 Lead wire 5a Concavity and convexity 10 Solar cell 13 Lead connection electrode 13a Convex part 13b Lead wire in lead connection electrode on the non-light-receiving surface side Connected surface (upper surface)

Claims (9)

A solar cell having a lead connection electrode for electrically connecting a lead wire with a conductive adhesive on the light receiving surface and the back surface thereof,
The lead connection electrode includes a plurality of protrusions on a surface connecting the lead wires;
A solar cell characterized by. The protrusion is provided to extend in a direction substantially parallel to a direction substantially orthogonal to the longitudinal direction of the lead connection electrode;
The solar battery cell according to claim 1. The protrusion has a rectangular shape with a predetermined angle with a direction substantially orthogonal to the longitudinal direction of the lead connection electrode;
The solar battery cell according to claim 1. The protrusion includes a portion extending in a direction substantially parallel to a direction substantially orthogonal to the longitudinal direction of the lead connection electrode, and a portion forming a predetermined angle with a direction substantially orthogonal to the longitudinal direction of the lead connection electrode. Presenting a U-shaped shape with
The solar battery cell according to claim 1. The projecting portion has a shape having a curved portion that forms a predetermined angle with a direction substantially orthogonal to the longitudinal direction of the lead connection electrode in the longitudinal direction of the lead connection electrode;
The solar battery cell according to claim 1. The protrusions are patterned in a plurality of rows extending in the longitudinal direction of the lead connection electrodes;
The solar cell according to any one of claims 3 to 5, wherein: The angle between the protruding portion and the direction substantially perpendicular to the longitudinal direction of the lead connection electrode increases as the protrusion moves away from the center in the longitudinal direction of the lead connection electrode.
The solar cell according to any one of claims 3 to 6, wherein: A plurality of solar cells according to claim 1 are arranged, and the lead wire and the lead connection electrode are electrically connected by the conductive adhesive and adjacent to the sun. Battery cells are electrically connected by the lead wires,
A solar cell module characterized by. The lead wire has a protrusion on a connection surface with the lead connection electrode;
The solar cell module according to claim 8.

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