JP2008227262A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the thickness of a solar battery and improve the productivity thereof. <P>SOLUTION: In a connection region ST where a conductor 41 is connected to finger electrodes 11, 12 formed on the solar battery cell 1, a pressure dispersion material 21 whose size is equal to or narrower than the width of the tab 41 is coated and formed between the finger electrodes by screen printing or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

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. 8 and 9 show a part of a conventional solar cell module. FIG. 9 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. 8, 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 the heating 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). 10 to 12 show a part of a solar cell module that is tab-connected using this method. FIG. 11 is an enlarged cross-sectional view showing a part of the cross section taken along line F-F ′ of FIG. 10 in the vicinity of 241. FIG. 12 is an enlarged cross-sectional view showing a part of a cross section taken along line G-G ′ of FIG. 10.

  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 as compared with 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 toward the solar battery cell 201 in order to embed the tip of the finger electrode 211 in the soft conductor layer 242 on the surface of the tab 241. At this time, if the pressure of the pressurization is too strong, the tip of the finger electrode 211 penetrates the soft conductor layer 242 and comes into contact with the surface of the tab 241. As a result, the pressure of the pressurization is directly transmitted to the cell surface through the finger electrode 211. There is a possibility that the solar battery cell 201 may be cracked or chipped. For this reason, conventionally, the optimum range of pressure during pressurization is narrowed, and productivity cannot be greatly improved.

  Then, an object of this invention is to provide the solar cell module which can improve productivity and can reduce the thickness of a photovoltaic cell.

  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 to each other by a wiring tab; and the plurality of solar cells disposed between the light receiving surface member and the back surface member. And the solar battery cell has a plurality of finger electrodes disposed on one main surface connected by the wiring tab, and the wiring tab includes the plurality of finger electrodes. A bonding layer for bonding the wiring tab and the one main surface between the conductive layer and the one main surface of the solar battery cell; And a pressure dispersion material.

  The solar cell module according to claim 1 has an adhesive layer and a pressure dispersion material for adhering the wiring tab and the one main surface between one main surface of the solar cell and the conductive layer. When bonding the wiring tab and one main surface of the solar battery cell by thermocompression bonding, 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, a decrease in yield during manufacturing is improved, and productivity is improved.

  The solar cell module according to claim 2 of the present invention is the solar cell module according to claim 1, wherein the contact area between the pressure dispersion material and the conductive layer is larger than the contact area between the finger electrode and the conductive layer. Features.

  According to the solar cell module of claim 2, when the wiring tab is bonded to one main surface of the solar battery cell, the finger electrode is slightly embedded in the surface of the conductive layer formed on the surface of the wiring tab. On the other hand, since the pressure dispersion material is configured to support the conductive layer, the pressure applied to the finger electrode formation 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 the solar cell module according to claim 3, the contact area between the pressure dispersion material and the conductive layer is substantially equal to the contact area between the finger electrode and the conductive layer, and both the pressure dispersion material and the finger electrode are in contact with each other. The surface is partially embedded in the conductive layer.

  According to the solar cell module according to claim 3, when the wiring tab is bonded to one main surface of the solar battery cell, the pressure dispersion material is slightly added to the surface of the conductive layer formed on the surface of the wiring tab together with the finger electrodes. Since it is embedded, the pressure concerning the finger electrode formation part on a photovoltaic cell can be relieved. Thereby, even when a photovoltaic cell is made thin, a cell crack can be prevented.

  The solar cell module according to the present invention is the solar cell module according to claim 1, wherein the pressure dispersion material is a conductive material. At this time, the pressure dispersion material may electrically connect the finger electrodes.

  According to such a solar cell module, when the wiring tab is bonded to one main surface of the solar cell, the pressure applied to the finger electrode forming portion on the solar cell can be reduced. Thereby, even when a photovoltaic cell is made thin, a cell crack can be prevented. Further, since the pressure dispersion material is a conductive material and is electrically connected to the finger electrode, the contact resistance between the wiring tab and the finger electrode is reduced, so that the current collecting effect can be improved.

  Moreover, the solar cell module according to the present invention is the solar cell module according to claim 1, wherein the adhesive layer is a resin material containing fine particles.

  According to this solar cell module, by making the adhesive layer a resin material containing fine particles, it is possible to increase the resistance to the compression and expansion / contraction of the solar cells without impairing the original adhesive force of the resin.

  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)
The solar cell module according to the first embodiment of the present invention will be described with reference to FIGS. The solar cell module according to the embodiment of the present invention is a solar cell module including solar cells having a so-called bus bar-less structure that does not use a bus bar electrode. FIG. 1 is a plan view of a solar battery cell in a solar battery module, FIG. 2 shows a cross section taken along the line AA ′ of FIG. 1, and FIG. 3 shows a main part on the light receiving surface side of the cross section AA ′. It is an enlarged one.

  The solar 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 n-type region of the solar battery cell 1. As shown in FIG. 3, 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, and about 50 are formed in a line on the surface of the solar battery cell 1. 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 is also composed of a plurality of finger electrodes formed in parallel to each other. On the back surface (not shown), the finger electrodes have, for example, a finger electrode width of 100 μm, a pitch of 2 mm, and an electrode thickness of 60 μm, and about 50 finger electrodes are formed in a line shape on the back surface of the solar battery cell 1. 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.

  In addition, since the back surface side of the photovoltaic cell 1 does not need to consider the reduction | decrease of a light-receiving area, it can also form more finger electrodes than the surface side. By increasing the number of finger electrodes, resistance loss on the back surface side can be reduced.

  And the solar cell module shown as 1st Embodiment is a connection area | region (it mentions later) to which the tabs 41 and 42 are connected with respect to the finger electrode (finger electrode 11 in the light-receiving side) formed on the photovoltaic cell 1. The pressure dispersion material 21 is provided between the finger electrodes. Hereinafter, when simply referred to as “finger electrode”, it includes the finger electrode 11 in the enlarged view on the light receiving surface side shown in FIG. 3 and the finger electrode formed on the back surface.

  The pressure dispersion member 21 has a function of dispersing the pressure applied to the finger electrodes when the tabs 41 and 42 are bonded. The material of the pressure dispersion material 21 may be conductive or insulating. In the case of conductivity, the pressure dispersion member 21 is electrically connected to the finger electrode, thereby reducing the resistance between the tabs 41 and 42 and the solar battery cell 1.

  Further, the thickness of the pressure dispersion material 21 may be the same as or different from the thickness of the finger electrode. The thickness of the pressure dispersion material 21 is appropriately set according to the area and shape so that the pressure applied to the finger electrodes when the tabs 41 and 42 are bonded can be dispersed.

  In the solar cell module according to the present embodiment, as shown in FIG. 3, the thickness of the pressure dispersion material 21 is smaller than the thickness of the finger electrode 11. Specifically, when the upper surface of the pressure dispersion material 21 is in contact with the surface of the soft conductor layer 51 coated on the surface of the tab 41, the tip of the finger electrode 11 is embedded in (embedded in) the soft conductor layer 51. The thickness of the pressure dispersion material 21 is set so as not to contact the surface of the tab 41. The area of the pressure dispersion material 21 is set larger than the area of the finger electrode 11. Specifically, the shape and size of the pressure dispersion material 21 in the planar direction are set to such a size and shape that it is difficult to sink into the soft conductor layer 51 due to the pressure when the tab 41 is bonded.

As the pressure dispersion material 21, an insulating SiO ₂ paste or the like can be used. The SiO ₂ paste as the pressure dispersion material 21 is applied and formed by screen printing or the like with a size equal to or smaller than the width of the tab 41 (see FIG. 3). Further, in the pressure dispersion material 21 used in the first embodiment, the contact area with the soft conductor layer 51 which is a conductive layer is larger than the contact area between the finger electrode 11 and the soft conductor layer 51.

  Although not shown, the pressure dispersion material 21 is similarly formed between the electrodes of the finger electrodes on the back surface.

  Tabs 41 and 42 are pressure-bonded to the connection region (dotted region ST shown in FIG. 4) via the adhesive layer 31 on the finger electrodes on the light receiving surface side and the back surface side. The adhesive layer 31 contains 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 thickness of the resin adhesive 31 is 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 copper thin plates, 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. However, basically, it is a conductive material that is softer than the finger electrode, and the adhesive layer 31. It is desirable to use a material that softens at a temperature at which the resin cures. Soft conductive metals can be used, including eutectic solder with a reduced melting point.

  FIG. 3 shows a cross section of the finger electrode, the pressure dispersion member, and the tab after the pressure bonding, and FIG. 4 shows a projection view seen from the light receiving surface side. As shown in FIG. 4, when viewed from the light-receiving surface direction, the solar cell module shown as the first embodiment is adjacent to the solar cell 1 in the region where the tab 41 is formed (connection region ST). A pressure dispersion material 21 is provided between the electrodes of the finger electrode 11. In the first embodiment, the pressure dispersion member 21 has a contact surface with the tab 41 that is formed on a gentle curved surface that is flatter or closer to flat than the finger electrode. Absent. As described above, in the solar cell module shown as the first embodiment, it is considered that the stress exerted on the solar cell 1 by the finger electrode at the time of crimping is dispersed by the pressure dispersion material 21, and the stress applied to the solar cell 1 is relieved. be able to. 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 eliminated. In addition, the limitation of the pressure bonding conditions becomes gentler than before, and the productivity is improved. Moreover, the thickness of the photovoltaic cell 1 can be made thin.

  In order to confirm that the problem of the solar battery cell 1 is alleviated, solar battery cells were manufactured by changing the thickness of the solar battery cell 1 of the first embodiment, and the yield was evaluated.

The solar battery cells of the examples were manufactured 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 had 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 was formed to a thickness of 40 μm on a copper thin plate having a tab thickness of 200 μm. In addition, as the pressure dispersion material 21, an insulating SiO ₂ paste was used. This SiO ₂ paste was applied and formed by screen printing with a size of 1.5 mm × 1.5 mm × thickness 30 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 finger electrode 12 was formed on the back 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 30 μm.

  In addition, in both the examples and the comparative examples, pressure bonding was performed by pressure bonding at a pressure of 2 Mpa for 15 seconds using a hot plate heated to 180 ° C.

  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.

  From the results shown in Table 1, in the solar cell module of the example, when the thickness of the solar cell is as thin as 200 μm, 160 μm, 120 μm, and 80 μ, the change in yield is 1,1,0.98,0.90. Yes, it was confirmed that the yield reduction can be suppressed as compared with the conventional example, that is, the solar cell module having no pressure dispersion material.

  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)
As described above, the solar cell module according to the first embodiment includes the pressure dispersion material 21 between at least one finger electrode in the connection region ST on the light receiving surface side or the back surface of the solar cell 1, thereby thermocompression bonding. When connecting the finger electrode and the tab 41 by the pressure, the pressure does not concentrate only on the part where the finger electrode 11 is formed on the solar cell 1, the cell crack can be prevented, and the thickness of the solar cell can be reduced. . Moreover, since the yield fall at the time of manufacture can be suppressed by this, productivity can be improved. Furthermore, the presence of the pressure dispersion material 21 between the finger electrodes alleviates the direct influence on the finger electrodes caused by the pulling, compression, twisting, and the like of the tab 41 due to a severe cold environment cycle under the usage environment of the solar cell module. be able to.

[Second Embodiment]
Hereinafter, 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 contact area between the pressure dispersion material formed on the surface of the solar battery cell 1 and the conductive layer coating the tab is substantially equal to the contact area between the finger electrode and the conductive layer, and the pressure dispersion In this embodiment, both the material and the finger electrode are formed so as to be buried in the conductive layer partially coating the tab on the contact surface.

  In order to confirm that the malfunction of the solar battery cell 1 was alleviated by the second embodiment, a solar battery module was manufactured under the same conditions as in the first embodiment, and the yield was evaluated. The yield was evaluated by “EL emission intensity distribution” as in the first embodiment.

In this embodiment, the pressure dispersion material was formed by applying screen-printing three SiO ₂ pastes having insulating properties at a size of 1.5 mm × 100 μm × thickness 40 μm at substantially equal intervals between the collecting electrodes. FIG. 5 shows an enlarged view of the AA ′ cross section of the solar cell module shown in the second embodiment after crimping, and FIG. 6 shows an enlarged view of the main part of the projected view seen from the light receiving surface side.

  As shown in FIG. 6, the solar cell module shown as the second embodiment is adjacent to the solar cell 1 in the region (connection region ST) on the solar cell 1 when viewed from the light receiving surface direction. Pressure dispersion materials 22 a, 22 b and 22 c are formed between the electrodes of the finger electrode 11.

  As shown in FIG. 5, in the second embodiment, the pressure dispersion materials 22 a, 22 b, 22 c and the finger electrode 11 are partially embedded in the soft conductor layer 51 at the contact surface with the soft conductor layer 51. . According to the solar cell module shown as the second embodiment, after pressure bonding, the pressure dispersion material 22 is slightly sunk into the surface of the soft conductor layer 51 together with the finger electrode 11, so that only the finger electrode is sunk into the soft conductor layer 51. In comparison, it is considered that the pressure applied to the solar battery cell 1 can be effectively dispersed.

  In the solar cell module shown as the second embodiment, the same results as shown in Table 1 were confirmed.

  Moreover, the temperature cycle test based on JIS specification was done using the solar cell module shown as 2nd Embodiment, and the solar cell module shown as a comparative example, and the change of the current collection characteristic was compared in both. The solar cell thickness was 200 μm. The solar cell module of the comparative example has a current collection characteristic reduction rate of 4% after the temperature cycle test (200 cycles), whereas the solar cell module of the second embodiment has a reduction rate of 2.5%. It was found that the temperature resistance was improved.

(Function and effect)

  According to the solar cell module shown as the second embodiment, in the crimping step, the pressure dispersion material is embedded in the surface of the conductive layer (soft conductor layer 51) coated on the tab 41 together with the finger electrodes. It is possible to prevent pressure from concentrating only on the part where the finger electrode 11 is formed on the solar battery cell 1 at the time of pressure bonding, and it is possible to prevent cell cracking. As a result, the mechanical strength when the thickness of the solar battery cell is reduced is increased. Moreover, since the yield fall at the time of manufacture can be suppressed by this, productivity can be improved. Furthermore, the presence of the pressure dispersion materials 22a, 22b, and 22c between the finger electrodes directly causes the finger electrodes to be pulled, compressed, twisted, etc., by the severe thermal environment cycle under the usage environment of the solar cell module. Can alleviate that.

[Third Embodiment]
Hereinafter, 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 second embodiment described above will be mainly described.

  The third embodiment is a case where the pressure dispersion material is a conductive material and the finger electrodes are electrically connected. In the present embodiment, the pressure dispersion material is applied and formed by screen printing using the same conductive material as that of the finger electrodes. FIG. 7 shows a projection view seen from the light receiving surface side after the pressure bonding of the third embodiment. As shown in FIG. 7, when viewed from the light receiving surface direction, the solar cell module shown as the third embodiment is adjacent to the solar cell 1 in the region where the tab 41 is formed (connection region ST). A pressure dispersion material for electrically connecting the electrodes of the finger electrode 11 is formed. Each of the pressure dispersion members 23a to 23h has a line width of 100 μm, and eight lines are formed at intervals of 100 μm within a width of 1.5 mm of the connection region ST. Moreover, the thickness of the pressure dispersion materials 23 a to 23 h is approximately the same as the thickness of the finger electrode 11.

  In order to confirm that the problem of the solar battery cell 1 is alleviated by the second embodiment, a solar battery module is manufactured under the same conditions as in the first embodiment, and “EL emission intensity distribution” as in the first embodiment. When the yield was evaluated by the solar cell module shown as the third embodiment, the same results as shown in Table 1 could be confirmed.

  Moreover, the current collection efficiency was compared using the solar cell module shown as the third embodiment and the solar cell module shown as an example of the first embodiment. The solar cell thickness was 200 μm. As a result, it was confirmed that the current collection efficiency (FF) was improved by 0.5% in the solar cell module of the third embodiment.

(Function and effect)
According to the solar cell module shown as the third embodiment, by having the pressure dispersion members 23a to 23h, it is possible to prevent the pressure from being concentrated only on the finger electrode forming portion on the solar cell 1 at the time of pressure bonding. , Cell cracking can be prevented. As a result, the mechanical strength when the thickness of the solar battery cell is reduced is increased. Moreover, since the yield fall at the time of manufacture can be suppressed by this, productivity can be improved. Furthermore, since the pressure dispersion material is made of a conductive material and electrically connected to the finger electrodes, the contact resistance between the tabs 41 and 42 and the finger electrodes is reduced, so that the current collecting effect can be improved.

(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.

  For example, the planar shape (or cross-sectional shape) of the pressure dispersion material is not limited to the shape of the first to third embodiments. For example, the present invention includes a structure that is recognized to have a pressure dispersion effect such as a dot shape, a rectangular shape, and a contact surface with a tab having a mountain shape or a wave shape.

  Moreover, although each embodiment mentioned above demonstrated the case where a finger electrode digs into the electrically conductive layer (soft conductor layer 51) which coats the tab 41 and takes an electrical connection, it does not restrict to this but it contacts only. This also includes cases where conductive connection is achieved. Further, on the connection surface with the finger electrode, a protrusion formed on the surface of the tab 41 or a protrusion formed on the surface of the soft conductor layer 51 may be recessed into the finger electrode.

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 the projection figure seen from the light-receiving surface side 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 the projection figure seen from the light-receiving surface side of the solar cell module which concerns on 2nd Embodiment of this invention. It is the projection figure seen from the light-receiving surface side of the solar cell module which concerns on 3rd Embodiment of this invention. It is a top view explaining the conventional solar cell module. It is sectional drawing which expands and shows a part of E-E 'cross section of the photovoltaic cell of the conventional solar cell module 100. FIG. It is a top view which shows the solar cell module 200 of the conventional bus barless structure. It is sectional drawing which expands and shows a part of F-F 'cross section of the conventional solar cell module 200. FIG. It is sectional drawing which expands and shows a part of G-G 'cross section of the conventional solar cell module 200. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Solar cell, 11, 12 ... Finger electrode, 21, 22, 23 ... Pressure dispersion material, 31 ... Adhesive layer, 41 ... Copper thin plate, 51 ... Soft conductor layer

Claims (6)

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 to each other by wiring tabs;
A sealing material disposed between the light receiving surface member and the back surface member, and embedded with the plurality of solar cells,
The solar battery cell has a plurality of finger electrodes arranged on one main surface connected by the wiring tab,
The wiring tab has a conductive layer on the surface for electrical connection with the plurality of finger electrodes, and the wiring tab and the one main surface are disposed between the conductive layer and the one main surface of the solar battery cell. The solar cell module which has the contact bonding layer and pressure dispersion material for adhere | attaching a surface.   2. The solar cell module according to claim 1, wherein a contact area between the pressure dispersion material and the conductive layer is larger than a contact area between the finger electrode and the conductive layer. The contact area between the pressure dispersion material and the conductive layer is substantially equal to the contact area between the finger electrode and the conductive layer,
2. The solar cell module according to claim 1, wherein both of the pressure dispersion material and the finger electrode are partially embedded in the conductive layer at a contact surface.   The solar cell module according to claim 1, wherein the pressure dispersion material is a conductive material.   The solar cell module according to claim 4, wherein the pressure dispersion material electrically connects the finger electrodes.   The solar cell module according to claim 1, wherein the adhesive layer is a resin material containing fine particles.

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