JP4974722B2 - Solar cell module manufacturing method and solar cell module - Google Patents

Description

  The present invention relates to a solar battery module including a plurality of solar battery cells connected to each other by connecting finger electrodes formed on the surfaces of adjacent solar battery cells with tabs.

  Solar cells are expected as a new energy source because they can directly convert light from the sun, a clean and inexhaustible energy source, into electricity.

  When such a solar cell is used as a power source for a house or a building, since the output per solar cell is as small as several watts, usually a plurality of solar cells are electrically connected in series or in parallel. Therefore, it is used as a solar cell module whose output is increased to several hundred watts. 7 and 8 show a part of a conventional solar cell module. FIG. 8 is an enlarged cross-sectional view showing a part of the cross section taken along line E-E ′ of FIG.

  The plurality of solar cells 101 are electrically connected by soldering to a collector electrode (bus bar electrode 121) printed and formed approximately equal to or larger than the tab width by tabs 141 made of a conductive material such as copper foil. Is done. Here, the tab 141 is a thin plate made of a metal such as copper. Further, solder 142 is coated around the tab 141. Further, the solar battery cell 101 includes an EVA or the like between a translucent surface member such as glass or translucent plastic and a back member made of a resin film such as a polyethylene terephthalate film, a steel plate, or a glass plate. It is sealed with a filler having translucency. Then, as shown in FIG. 7, each adjacent solar battery cell has a bus bar electrode 121 in the collector electrode provided on the light receiving surface side of one solar battery cell and a back electrode of the other solar battery by tabs 141. By being connected, they are electrically connected to each other (see, for example, Patent Document 1).

  By the way, in order to reduce the cost and resource of solar cells, it is required to make the solar cells thinner. When the solar cell is thinned, when the tab 141 is connected to the bus bar electrode 121 on the solar cell using solder, a line between the tab 141 made of, for example, copper foil and the solar cell made of a silicon substrate is used. Since the expansion coefficients are greatly different, warping stress may occur due to the expansion and contraction of each material due to heating and cooling applied in the soldering operation, which may cause cell cracking or electrode peeling. For this reason, it was difficult to make the solar battery cell thinner.

  In addition, when the thickness of the tab is increased to reduce the series resistance of the tab and increase the output of the solar cell module, there is a problem that a problem in terms of physical properties is likely to occur.

  Therefore, the present applicant has applied for a method of connecting a tab on a solar cell using a resin adhesive (Japanese Patent Application No. 2006-229209). 9 to 11 show a part of a solar cell module that is tab-connected using this method. FIG. 10 is an enlarged cross-sectional view showing a part of the cross section taken along line F-F ′ of FIG. 9 in the vicinity of 241. FIG. 11 is an enlarged cross-sectional view showing a part of a cross section taken along line G-G ′ of FIG. 9.

  The plurality of solar battery cells 201 have a plurality of finger electrodes 211 that extend along one direction on the main surface and are arranged in parallel to each other. The tab 241 is made of a low resistance material such as copper, and a soft conductor layer 242 such as solder is provided on the surface. As shown in FIGS. 11 and 12, the tab 241 is connected by a resin adhesive 231. Also, as shown in FIG. 12, the tips of the finger electrodes 211 are embedded in the soft conductor layer 242 so that the tabs 241 and the finger electrodes 211 are electrically connected.

  Further, the solar battery cell 201 includes a translucent surface member such as glass or translucent plastic, a resin film such as a PET (polyethylene terephthalate) film, a laminated film of a resin film and a metal film, or a steel plate or stainless steel. Sealed with a light-transmitting filler such as EVA between the back member made of a plate or the like.

In this method, since the resin adhesive is used for the tab connection, the temperature at the time of bonding can be reduced compared to the connection by solder. For this reason, since the influence resulting from the above-mentioned thermal expansion can be reduced, it becomes possible to make the thickness of a photovoltaic cell thin compared with the past.
JP 2002-359388 A

  However, in the method of performing tab connection with a resin adhesive, it is necessary to press the tab 241 in the solar cell direction in order to embed the tip end portion of the finger electrode in the soft conductor layer 242. Part of the pressure at this time is transmitted to the solar battery cell through the finger electrode. In particular, depending on the positional relationship between the finger electrode 211 arranged on the light receiving surface of the solar battery cell and the finger electrode arranged on the back surface side, the following problems may occur.

  FIG. 12 shows a G-G ′ cross section of the solar battery cell 201 in this case. As shown in FIG. 12, in the method of performing tab connection using a resin adhesive, the positional relationship between the finger electrode 211 formed on the light receiving surface of the solar battery cell 201 and the finger electrode 212 formed on the back surface is completely deviated. In the structure, in the step of simultaneously pressing the front and back tabs from both the front and back sides, a shear stress acts on the solar battery cell 201, and the load is accumulated in the cell, so that cracks 221a and 221b are likely to occur.

  Then, an object of this invention is to provide the solar cell module which can suppress generation | occurrence | production of the above cracks and can suppress a yield fall.

  In order to achieve the above-described object, a solar cell module according to claim 1 of the present invention includes a light receiving surface member disposed on the light receiving surface side, a back surface member disposed on the counter light receiving surface side, and the light receiving surface. A plurality of solar cells disposed between the surface member and the back surface member and electrically connected by wiring tabs, and disposed between the light receiving surface member and the back surface member, the plurality of solar cells being A sealing material to be embedded, wherein the solar cell is disposed on a light receiving surface and is connected to the wiring tab, and a plurality of first finger electrodes connected to the wiring tab and connected to the wiring tab. A plurality of second finger electrodes, and the first finger electrode and the second finger electrode are arranged at positions where at least a part of the first finger electrode and the second finger electrode overlap each other on a projection surface parallel to the light receiving surface or the back surface. It is characterized by being.

  The solar cell module according to claim 1, wherein the first finger electrode and the second finger electrode are arranged at positions where at least part of the first finger electrode and the second finger electrode overlap each other on a projection surface parallel to the light receiving surface or the back surface. When pressure is applied in the direction of the solar battery cell and bonded, the pressure applied to the finger electrode forming portion on the solar battery cell can be relaxed. Thereby, even when a photovoltaic cell is made thin, a cell crack can be prevented. In addition, since the mechanical strength of the solar battery cell is improved, it is possible to improve a decrease in yield at the time of manufacturing and improve productivity.

  The solar cell module according to claim 2 of the present invention is the solar cell module according to claim 1, wherein the same number of the first finger electrodes and the second finger electrodes are formed. The electrode width of the electrode is larger than the electrode width of the first finger electrode.

  In the solar cell module according to claim 2, since the electrode width of the second finger electrode is larger than the electrode width of the first finger electrode on the projection surface parallel to the light receiving surface or the back surface, The restriction in the process of forming the finger electrodes on the surface and the back surface is relaxed, so that it is possible to improve the yield reduction and improve the productivity.

  The solar cell module according to claim 3 is the solar cell module according to claim 1, wherein the second finger electrodes are formed in a larger number than the first finger electrodes, and the projection surface is parallel to the light receiving surface or the back surface. Above, the 2nd finger electrode formed in the position which does not overlap with the 1st finger electrode exists, It is characterized by the above-mentioned.

  In the solar cell module according to claim 3, since the second finger electrodes are formed in a larger number than the first finger electrodes on the light receiving surface or the projection surface parallel to the back surface, the light receiving surface of the solar cells. And the restriction in the process of forming the finger electrodes on the back surface is relaxed, so that it is possible to improve the decrease in yield at the time of manufacturing and improve the productivity.

  The solar cell module according to claim 4 is the solar cell module according to claim 1, wherein the second finger electrodes are formed in a larger number than the first finger electrodes, and the projection surface is parallel to the light receiving surface or the back surface. Above, the height from the back surface of the 2nd finger electrode arrange | positioned in the position which at least one part and 1st finger electrode overlap mutually is the height of the 2nd finger electrode which is not in the position which overlaps with the 1st finger electrode. It is characterized by higher than that.

  5. The solar cell module according to claim 4, wherein the height of the second finger electrode that is not at a position at least partially overlapping with the first finger electrode on the projection surface parallel to the light receiving surface or the back surface is the first finger. When the wiring tab is pressed and bonded in the direction of the solar battery cell, it is applied to the finger electrode forming portion on the solar battery cell by being higher than the height of the second finger electrode at least partially overlapping the electrode. Pressure can be relieved. Thereby, even when a photovoltaic cell is made thin, a cell crack can be prevented. In addition, since the mechanical strength of the solar battery cell is improved, it is possible to improve a decrease in yield at the time of manufacturing and improve productivity.

  Furthermore, the solar cell module according to claim 5 is the solar cell module according to claim 4, wherein the wiring tab has a conductive layer on the surface for electrical connection with the plurality of finger electrodes, and the light receiving surface. Alternatively, on the projection plane parallel to the back surface, the height from the back surface of the second finger electrode disposed at a position where at least a portion of the first finger electrode and the first finger electrode overlap with each other, and the first finger electrode not positioned at the position where it overlaps with the first finger electrode. The difference in height between the two finger electrodes is smaller than the thickness of the conductive layer.

  The solar cell module according to claim 5 is not located at a position where the first finger electrode and the first finger electrode overlap with the height from the back surface of the second finger electrode arranged at a position where at least a part of the first finger electrode overlaps each other. Since the difference in height between the second finger electrodes is smaller than the thickness of the conductive layer, the pressure applied to the finger electrode forming part on the solar battery cell is reduced when the wiring tab is pressed and bonded in the direction of the solar battery cell. can do. Thereby, even when a photovoltaic cell is made thin, a cell crack can be prevented. In addition, since the mechanical strength of the solar battery cell is improved, it is possible to improve a decrease in yield at the time of manufacturing and improve productivity.

  ADVANTAGE OF THE INVENTION According to this invention, productivity can be improved and the solar cell module which can reduce the thickness of a photovoltaic cell can be provided.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First Embodiment]
(Solar cell module)
A solar cell module according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of a solar battery cell in a solar battery module, FIG. 2 shows a cross-section AA ′ of FIG. 1, and FIG. 3 is an enlarged view of a main part of the AA ′ cross-section. is there.

  The solar battery cell 1 according to the present embodiment is made of a crystalline semiconductor such as single crystal silicon or polycrystalline silicon having a thickness of about 0.15 mm, and has a substantially square shape with one side being 100 mm. This solar cell 1 has an n-type region and a p-type region, and a semiconductor junction is formed at the interface between the n-type region and the p-type region. In addition, a structure in which a substantially intrinsic amorphous silicon layer is sandwiched between a single crystal silicon substrate and an amorphous silicon layer, defects at the interface are reduced, and characteristics of the heterojunction interface are improved, so-called A solar battery cell having a HIT structure may be used.

  A surface electrode is formed on the light receiving surface side surface (hereinafter referred to as “light receiving surface”) of the solar battery cell 1. The surface electrode includes a plurality of finger electrodes 11 formed in parallel to each other. The finger electrodes 11 have, for example, a finger electrode width of 100 μm, a pitch of 2 mm, and an electrode thickness of 60 μm. Such a surface electrode is formed, for example, by screen printing a silver paste and curing it at a temperature of a few hundred degrees.

  Similarly, a back electrode is provided on the back surface of the solar cell 1 (hereinafter referred to as “back surface”). This back electrode also includes a plurality of finger electrodes 12 formed in parallel to each other. The finger electrodes 12 have, for example, a finger electrode width of 100 μm, a pitch of 2 mm, and an electrode thickness of 60 μm. Such a surface electrode is formed, for example, by screen printing a silver paste and curing it at a temperature of a few hundred degrees.

  And in 1st Embodiment, the finger electrode 11 formed in the shape of a line on the main surface of the photovoltaic cell 1 according to a predetermined arrangement direction, and the finger electrode 12 formed in the shape of a line on the back surface are the photovoltaic cells. On the projection plane parallel to one main surface, at least a part of each finger electrode is formed at a position where they overlap each other. Especially in 1st Embodiment, it formed so that the centerline of the finger electrode 11 and the centerline of the finger electrode 12 may correspond substantially (refer FIG. 3).

  Tabs 41 and 42 are pressure-bonded to the finger electrode 11 or the finger electrode 12 on the light receiving surface side and the back surface side via adhesive layers 31 and 32. The adhesive layers 31 and 32 contain an epoxy resin as a main component and a crosslinking accelerator that rapidly accelerates crosslinking by heating at 180 ° C. and completes curing in about 15 seconds. The adhesive layers 31 and 32 have a thickness of 0.01 to 0.05 mm, and the width is preferably equal to or smaller than the tab 41 in consideration of shielding of incident light. In the present embodiment, a resin adhesive formed on a belt-like film sheet having a width of 1.5 mm and a thickness of 0.02 mm is used.

  The tabs 41 and 42 are made of a copper thin plate, and the surface of the tab 41 has a soft conductor layer 51 formed by plating tin. In the present embodiment, it has been described that tin is used as the soft conductor layer 51 that coats the tabs 41 and 42, but basically, the conductive material is softer than the finger electrodes 11 and 12, and It is desirable to use a material that softens at a temperature at which the adhesive layers 31 and 32 are cured. Soft conductive metals can be used, including eutectic solder with a reduced melting point.

  FIG. 3 is an enlarged view of a main part in the A-A ′ cross section of the solar battery cell. As shown in FIG. 3, in the solar cell module shown as the first embodiment, the finger electrodes 11 and 12 on the front surface or the back surface of the solar cell 1 are on a projection plane parallel to the main surface of the solar cell 1. Since they are formed so as to overlap each other, the pressure applied at the time of pressure bonding is canceled by the front and back, and the shear stress on the cell can be relaxed. Thereby, the malfunction of the solar cell module resulting from the fracture | rupture etc. of the cell at the time of crimping | compression-bonding can be reduced.

  In order to confirm that the malfunction of the solar cell 1 is alleviated, the front and back finger electrodes are formed so that the center deviation of the front and back finger electrodes is substantially 0 μm, and the thickness of the solar cell 1 is changed. Solar cells were fabricated and the yield was evaluated.

  The solar battery cells of the examples were prepared with cell sizes of 104 mm square and cell thicknesses of 200 μm, 160 μm, 120 μm, and 80 μm. In the produced solar cell module, the finger electrodes 11 and 12 both have a finger electrode width of 100 μm, a pitch between the finger electrodes of 2 mm, and a thickness of the finger electrodes of 60 μm. The tab width was 1.5 mm, and a SnAgCu plating layer having a thickness of 40 μm was formed as a soft conductor layer on a copper thin plate having a tab thickness of 200 μm.

  As a comparative example, the finger electrode 11 was formed on the surface of the solar battery cell with a finger electrode width of 100 μm, a pitch between the finger electrodes of 2 mm, and a thickness of the finger electrodes of 60 μm. The same four types of cell thickness (200 μm, 160 μm, 120 μm, and 80 μm) were prepared. Moreover, the photovoltaic cell which prepared the finger electrode 12 with the finger electrode width | variety of 100 micrometers, the pitch between finger electrodes of 2 mm, the thickness of a finger electrode at 30 micrometers on this solar cell back surface was prepared. The solar cell of the comparative example has a relationship in which the centers of the finger electrodes formed on both the front and back surfaces are shifted by 120 μm. Note that the positional relationship between the finger electrode 11 and the finger electrode 12 is substantially the same over the entire length of the finger.

  In addition, in both the examples and the comparative examples, pressure bonding was performed for 15 seconds from both the front and back sides with a pressure of 2 Mpa using a hot plate heated to 180 ° C. The cross-sectional state after the pressure bonding of the first embodiment is shown in FIG.

  For the calculation of the yield, 100 solar cells were produced for each of the solar cell thicknesses of 200 μm, 160 μm, 120 μm, and 80 μm, and evaluated by “EL emission intensity distribution”. When a current of 2 A is passed through the solar battery cell, ultraviolet light emission near 1000 nm is observed. When an EL light emission measuring device composed of an imaging device capable of capturing this invisible light emission and imaging software is used to observe a cell with a crimped tab, the cracks generated during pressure bonding do not emit light. Impossible cracks can be detected. When a crack was found even at one location in one solar battery cell, the yield was calculated as NG. The yield is expressed as a relative value with a thickness of 200 μm of a solar battery cell produced as a comparative example being 1. The results are shown in Table 1. Table 1 shows the results when the center deviation of the front and back finger electrodes is substantially 0 μm.

  From the results shown in Table 1, the solar cell was formed so that the center line of the finger electrode 11 and the center line of the finger electrode 12 substantially coincide on the projection plane parallel to the main surface of the solar cell 1. It was confirmed that a decrease in yield when the thickness of the substrate was reduced could be suppressed.

  In the present embodiment, the adhesive layer 31 is described as having an epoxy resin as a main component. However, the adhesive layer 31 can be bonded at a temperature lower than that of solder bonding, preferably 200 ° C. or less, and does not significantly impair productivity. As long as curing is completed in about 20 seconds. For example, in addition to acrylic resins that have a low curing temperature and can contribute to the reduction of thermal stress, thermosetting resin adhesives such as polyurethane with high flexibility, thermoplastic adhesives such as EVA resins and synthetic rubbers, It is also possible to use a two-component reaction adhesive that is bonded by mixing a curing agent with an epoxy resin, an acrylic resin, or a urethane resin as a main component that enables bonding at a low temperature.

  In this embodiment, a resin adhesive is used as the adhesive layer 31, but the adhesive layer 31 is not limited to a resin, and any material that can be bonded at a lower temperature than solder can be used.

  Further, when the resin adhesive layer is used, if the resin adhesive contains fine particles, the mechanical strength of the solar cell module can be improved. Here, the fine particles have a size of 2 to 30 μm, preferably an average particle size of about 10 μm, and nickel, gold-coated nickel, or a plastic coated with a conductive metal (for example, coated with gold) (Plastic) can be used alone or in combination. By mixing these fine particles, the stress resistance of the cell can be enhanced without impairing the original adhesive force of the resin. The different kind of fine particles mixed in the resin can obtain the same effect that the resistance to compression, expansion and contraction can be increased by adding aggregate and iron to cement, for example. Long-term reliability can be further improved.

(Function and effect)
The solar cell module according to the first embodiment includes a plurality of solar cells in which finger electrodes 11 and finger electrodes 12 are formed at positions where individual finger electrodes overlap each other on a projection plane parallel to the main surface of solar cell 1. The battery cells are connected by tabs 41 and 42 that are electrically connected directly to the finger electrode 11 and the finger electrode 12.

  Therefore, according to the solar cell module which concerns on 1st Embodiment, the finger electrode 11 formed in the main surface (front surface) of the photovoltaic cell 1 and the finger electrode 12 are formed in the back surface position corresponding to this. Thus, the stress applied to the solar battery cell at the time of pressure bonding is relaxed. In addition, this can prevent accumulation of damage to the solar battery cells, and can suppress a decrease in yield during manufacturing.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the drawings. In the following, differences between the first embodiment and the second embodiment described above will be mainly described. In addition, since the planar external appearance of the solar cell module shown as 2nd Embodiment is not different from the solar cell module of 1st Embodiment, it demonstrates using FIG. 1 in order to show the positional relationship of a cross section.

  In the second embodiment, the finger electrode 11 formed on the surface of the solar cell 1 and the finger electrode 12 formed on the back surface are at least partially in a projection plane parallel to the main surface of the solar cell 1. It is embodiment in the case of being formed in the overlapping position.

  In order to confirm that the problem of the solar battery cell 1 is alleviated, a solar battery module was manufactured under the same conditions as in the first embodiment. The deviation x between the finger electrode 11 formed on the main surface (front surface) of the solar battery cell 1 and the center (finger center) of the finger electrode 12 formed on the corresponding back surface position is 0 μm <x <120 μm. The yield was evaluated by changing the range. FIG. 4 shows a cross-sectional state after crimping according to the second embodiment. Table 2 shows the results of yield evaluation. The yield was evaluated by “EL emission intensity distribution” as in the first embodiment.

ずれｘが０μｍのとき、歩留まりは１であり、ずれ２０μｍのとき歩留まりは１であり、ずれ５０μｍのとき歩留まりは０．９９であり、ずれ１００μｍのとき歩留まりは０．９５であり、ずれ１１０μｍのとき歩留まりは０．８０であり、ずれ１２０μｍのとき歩留まりは０．７５である。

When the deviation x is 0 μm, the yield is 1, when the deviation is 20 μm, the yield is 1, when the deviation is 50 μm, the yield is 0.99, when the deviation is 100 μm, the yield is 0.95, and the deviation is 110 μm. When the yield is 0.80, when the deviation is 120 μm, the yield is 0.75.

  According to the results shown in Table 2, when the deviation x exceeds 110 μm, the yield rapidly decreases, and as the deviation x approaches 120 μm, the yield further decreases. That is, the finger electrode 11 formed on the front surface of the solar battery cell 1 and the finger electrode 12 formed on the back surface are in a positional relationship in which at least a part thereof overlaps on the projection plane parallel to the main surface of the solar battery cell 1. It can be seen that the shear stress exerted on the solar battery cell 1 is relaxed.

  In the second embodiment, the finger electrode 11 formed on the surface of the solar cell 1 and the finger electrode 12 formed on the back surface are at least partially on the projection plane parallel to the main surface of the solar cell 1. Is an example for explaining that an effect equivalent to that of the first embodiment is expected, and a numerical range of 0 μm <x <120 μm indicates that the finger electrode width in this embodiment is It is a numerical range resulting from being 100 micrometers, Comprising: It is not limited to this.

(Function and effect)
In the solar cell module according to the second embodiment, the finger electrodes 11 and the finger electrodes 12 are formed at positions where at least a part of the individual finger electrodes overlap each other on a projection plane parallel to the main surface of the solar cell 1. A plurality of solar cells are connected by tabs 41 and 42 that are electrically connected directly to the finger electrode 11 and the finger electrode 12.

  In the solar cell module according to the second embodiment, when the deviation x between the centers of the finger electrode 11 and the finger electrode 12 exceeds 110 μm, the yield decreases rapidly, but the projection plane is parallel to the main surface of the solar cell 1. In this case, if the positional relationship is at least partially overlapped, it can be said that the shear stress exerted on the solar battery cell 1 at the time of pressure bonding can be relaxed, and the yield can be suppressed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to the drawings. In the following, differences between the first embodiment and the third embodiment described above will be mainly described. In addition, since the planar external appearance of the solar cell module shown as 3rd Embodiment is not different from the solar cell module of 1st Embodiment, it demonstrates using FIG. 1 in order to show the positional relationship of a cross section.

  In the third embodiment, the same number of finger electrodes 11 as the finger electrodes 13 formed on the front surface are formed on the back surface of the solar battery cell 1, and the length of the line width of the finger electrodes 13 is the same as that of the finger electrodes 11. It is characterized by being larger than the length of the line width. Such a solar cell module is formed at a position where the finger electrode 11 completely overlaps the finger electrode 13 on the projection plane parallel to the main surface of the solar cell 1.

  In 3rd Embodiment, the width | variety of the finger electrode 13 formed in the back surface was 200 micrometers while the width | variety of the finger electrode 11 formed in the surface of the photovoltaic cell 1 was 100 micrometers. FIG. 5 shows a cross-sectional state after bonding. In addition, in 2nd Embodiment, the shift | offset | difference of the finger center of the finger electrode 11 formed in the surface of the photovoltaic cell 1 and the finger center of the finger electrode 13 formed in the back surface was made to be 10 micrometers or less.

  In 3rd Embodiment, by making the finger electrode width | variety of the finger electrode 13 formed on the back surface of the photovoltaic cell 1 larger than the finger electrode 11 formed on the surface, the surface and back surface of the photovoltaic cell 1 As a result, the conditions for adjusting the finger electrode formation position, that is, the finger center deviation x, become milder. Therefore, it was possible to maintain the same yield under the same conditions as in the first embodiment. Thereby, productivity can be improved.

  Moreover, the effect similar to increasing the number of finger electrodes is acquired by enlarging the electrode width of the finger electrode formed on the back surface of the photovoltaic cell 1, and the resistance loss on the back electrode side is reduced. Can do. Thereby, in 3rd Embodiment, the conversion efficiency in the back surface side of the photovoltaic cell 1 improved, and the fill factor (FF) improved 0.5% among output characteristics.

(Function and effect)
According to the solar cell module shown as the third embodiment, the line width of the finger electrode 13 formed on the back surface of the solar battery cell 1 is larger than the line width of the finger electrode 11 formed on the surface. On the projection plane parallel to the main surface of the solar battery cell 1, at least a part of the individual collector electrodes is naturally formed at a position where they overlap each other, so that finger electrodes are formed on the front and back surfaces of the solar battery cell 1. Limits in the process can be relaxed, and productivity can be improved. Moreover, resistance loss on the back electrode side can be reduced by increasing the electrode width of the finger electrode formed on the back surface of the solar battery cell 1.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to the drawings. Below, the difference between 1st Embodiment mentioned above and 4th Embodiment is demonstrated. In addition, since the planar external appearance of the solar cell module shown as 4th Embodiment is not different from the solar cell module of 1st Embodiment, it demonstrates using FIG. 1 in order to show the positional relationship of a cross section.

  In 1st Embodiment, although the number of the finger electrodes 12 formed on the back surface of the photovoltaic cell 1 was made into the same number as that of the finger electrode 11 formed on the surface, the back surface of the photovoltaic cell 1 is sunlight. In view of the resistance loss at the finger electrodes, it is generally expected that the output on the back surface of the solar cell 1 is increased by increasing the number of finger electrodes. Therefore, the fourth embodiment has a structure in which finger electrodes 15 are added between the finger electrodes 14 formed symmetrically on the front and back surfaces on the back surface of the solar cell 1 of the first embodiment.

  Although the heights of the finger electrodes 14 and 15 formed on the back surface of the solar battery cell 1 may all be the same, in the fourth embodiment, on the projection plane parallel to the main surface of the solar battery cell 1, The height hf2 from the solar cell 1 of the finger electrode 14 formed at a position where at least a part of the finger electrode 11 and the finger electrode 11 overlap each other overlaps the finger electrode 11 on a projection plane parallel to the main surface of the solar cell 1. It is characterized by being higher than the height hf1 of the finger electrode 15 that is not located. A solar cell module shown as the fourth embodiment under the same conditions as the first embodiment was produced. FIG. 6 shows a cross-sectional state after pressure bonding according to the fourth embodiment.

  In the solar cell module shown as the fourth embodiment, in consideration of the shear stress applied to the solar cell 1, when the height hf1 of the finger electrode 15 is set lower than the height hf2 of the finger electrode 14, the solar cell 1 is subjected to pressure bonding. After the finger electrode 11 and the finger electrode 14 that exist symmetrically on the front surface and the back surface of the slab are recessed into the soft conductor layers 51 and 52 coated around the tabs 41 and 42, the soft conductivity of the tab 42 is formed on the back surface. It is considered that the finger electrode 15 having a low height comes into contact with the body layer 52 gently and sinks. Thereby, the stress dispersion | distribution at the time of pressure bonding can be aimed at. As a result of calculating the yield in the same manner as in the first embodiment, it was possible to obtain the same effect as in Table 1.

  The difference in height (hf2−hf1) between the finger electrodes 14 and 15 on the back surface of the solar battery cell 1 is smaller than the thickness hm of the soft conductor layers 51 and 52 coated around the tabs 41 and 42. It is preferable. By adopting this configuration, it is possible to improve the yield reduction accompanying the reduction in the thickness of the solar battery cell 1 and improve the conversion efficiency. In 4th Embodiment, the height difference (hf2-hf1) of two types of finger electrodes formed on the back surface of the photovoltaic cell 1 was made to be substantially unified with 30 micrometers.

(Function and effect)
As described above, in the solar cell module shown as the fourth embodiment, more finger electrodes are formed on the back surface than the light receiving surface of the solar cell 1, and the projection parallel to the light receiving surface or the back surface of the solar cell 1. The height from the solar cell 1 of the finger electrode 14 formed at a position where at least a part of the finger electrode 11 and the finger electrode 11 overlap each other on the surface is on the projection surface parallel to the light receiving surface or the back surface of the solar cell 1, Since it is higher than the height of the finger electrode 15 that does not overlap the finger electrode 11, the stress of the solar battery cell 1 at the time of pressure bonding can be dispersed. The difference in height between the finger electrode 14 and the finger electrode 15 is preferably smaller than the layer thickness of the soft conductor layers 51 and 52 coated around the tab 41. By making it smaller than the layer thickness of the soft conductor layers 51 and 52, the stress applied to the solar battery cell 1 at the time of pressure bonding can be efficiently dispersed.

(Other changes)
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

It is a top view of the solar cell module concerning a 1st embodiment of the present invention. It is sectional drawing which shows the A-A 'cross section of the solar cell module which concerns on 1st Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the A-A 'cross section of the solar cell module which concerns on 1st Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the A-A 'cross section of the solar cell module which concerns on 2nd Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the A-A 'cross section of the solar cell module which concerns on 3rd Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the A-A 'cross section of the solar cell module which concerns on 4th Embodiment of this invention. It is a top view explaining the conventional solar cell module. It is sectional drawing explaining the E-E 'cross section of the photovoltaic cell of the conventional solar cell module. It is a top view which shows the conventional solar cell module. It is sectional drawing which shows the F-F 'cross section of the conventional solar cell module. It is sectional drawing which expands and shows the principal part of the G-G 'cross section of the conventional solar cell module. It is sectional drawing which expands and shows the principal part of a G-G 'cross section explaining the subject of the conventional solar cell module.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Solar cell, 11, 12, 13, 14, 15 ... Finger electrode, 31, 32 ... Adhesive layer, 41, 42 ... Tab, 51, 52 ... Soft conductor layer

Claims (10)

A light receiving surface member disposed on the light receiving surface side;
A back member disposed on the side opposite to the light receiving surface;
A plurality of solar cells disposed between the light receiving surface member and the back surface member and electrically connected by wiring tabs;
A solar cell module manufacturing method comprising: a sealing material that is disposed between the light receiving surface member and the back surface member and embeds the plurality of solar cells,
The solar cell has a plurality of first finger electrodes disposed on the light receiving surface and connected to the wiring tab, and a plurality of second finger electrodes disposed on the back surface and connected to the wiring tab. And
The wiring tab has a conductive layer on the surface,
In the step of electrically connecting the wiring tab to the solar battery cell, a resin adhesive is interposed on the first finger electrode and the second finger, respectively, so that the tip portion is embedded in the conductive layer. comprising the step of crimping the wire tabs,
The method for producing a solar cell module, wherein the first finger electrode and the second finger electrode are disposed at positions where at least a part of the first finger electrode and the second finger electrode overlap each other on a projection plane parallel to the light receiving surface or the back surface. . The first full Inga electrode and the second full Inga electrode is equal formed together, the electrode width of the second full Inga electrode, and greater than the electrode width of the first full Inga electrode The manufacturing method of the solar cell module of Claim 1. The second full Inga electrode, the being the number is more than the first finger electrodes in the light receiving surface or the back surface and parallel projection plane, which is formed at a position which does not overlap the first full Inga electrode method for manufacturing a solar cell module according to claim 1, wherein said second full Inga electrode is present. The second full Inga electrodes, said first and number is a number than the finger electrodes, in the light receiving surface or the back surface and parallel projection plane, at least partially overlap each other positioned between the first full Inga electrode height from the rear surface of the deployed second full Inga electrode, the claim 1, wherein the higher than a height of the first full Inga electrode and overlaps not positioned the second full Inga electrode Manufacturing method for solar cell module. Prior SL-receiving surface or the back surface and parallel projection plane, the height from the back surface of the first full Inga electrode and at least the portion of which is disposed in overlapping positions from each other the second full Inga electrode, the first off difference in height Inga electrode and overlaps not positioned the second full Inga electrode, method of manufacturing a solar cell module according to claim 4, wherein said conductive layer is smaller than the thickness. A solar cell module comprising a plurality of solar cells electrically connected by wiring tabs between the light receiving surface member and the back surface member,
The solar battery cell has a plurality of first finger electrodes disposed on the light receiving surface and a plurality of second finger electrodes disposed on the back surface,
The wiring tab has a conductive layer on the surface,
The wiring tab is connected to the first finger electrode and the second finger electrode by interposing a resin adhesive and crimping so that the tip portion is embedded in the conductive layer ,
The solar cell module, wherein the first finger electrode and the second finger electrode are arranged at positions where at least a part of the first finger electrode and the second finger electrode overlap each other on a projection plane parallel to the light receiving surface or the back surface. The first full Inga electrode and the second full Inga electrode is equal formed together, the electrode width of the second full Inga electrode, and greater than the electrode width of the first full Inga electrode The solar cell module according to claim 6. The second full Inga electrode, the being the number is more than the first finger electrodes in the light receiving surface or the back surface and parallel projection plane, which is formed at a position which does not overlap the first full Inga electrode solar cell module according to claim 6, wherein said second full Inga electrode is present. The second full Inga electrodes, said first and number is a number than the finger electrodes, in the light receiving surface or the back surface and parallel projection plane, at least partially overlap each other positioned between the first full Inga electrode disposed a second full height from the back of Inga electrodes claim 6 or 7, wherein the higher than a height of the first full Inga electrode and overlaps not positioned the second full Inga electrode The solar cell module according to. Prior SL-receiving surface or the back surface and parallel projection plane, the height from the back surface of the first full Inga electrode and at least the portion of which is disposed in overlapping positions from each other the second full Inga electrode, the first off wherein not positioned overlapping the Inga electrodes difference in height of the second full Inga electrodes, a solar cell module according to claim 6, wherein said conductive layer is smaller than the thickness.

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